Renderer: the ExternalPipeline hook, with the shadow request and its culling in gfx/external.rs

Step a of #14035 (layer plan M6). An external shader pipeline implements ExternalPipeline; the renderer calls begin_frame and shadow_request on world frames, resize and reset_history, and draws vanilla's way where it doesn't answer. Nothing sets one yet: each point is one Option test. ShadowView moves from pack_post (re-exported there) and ShadowCull, shadow_box, shadow_runs and shadow_casters from gfx.rs, unchanged: the engine's side of the shadow frame point. Co-Authored-By: Claude Opus 5.5 <[email protected]>
Merge pull request #13606 from martipops/controller/dial-4-editor
2026-11-10 10:31:29 -10:00 · 2026-11-10 05:17:39 +01:00 · 2026-11-10 00:05:14 +01:00 · 2026-11-10 00:05:08 +01:00 · 2026-11-09 23:57:55 +01:00 · 2026-11-09 23:57:51 +01:00
478 changed files with 27185 additions and 13945 deletions
@@ -13,4 +13,3 @@
 87152661 rdbtCVS         # added by Ludovic, 2026-10-27
 84875247 Online5277      # added by Ludovic, 2026-10-27 (his top three by merged pull requests)
 86072227 levzzz5154      # added by Ludovic, 2026-10-28 (Horizon Team; author of horizon-mixins)
-169198624 itarqos5        # added by Ludovic, 2026-11-08 (Discord Literal; Horizon Team)
@@ -186,7 +186,7 @@ state stays separate from the library tests. This compiles gameplay twice for ex
 | Resource packs | L: `packs.rs` + `packs/`, `pack_screen.rs`, `atlas_sources.rs`, `sprites.rs`, `mipmap.rs`, `model_library.rs`, `font.rs`, `mobs/cem.rs` + `mobs/cem_anim.rs` (OptiFine/EMF entity models and their animations); `horizon-client-core/src/lang.rs`; crates `horizon-assets`, `horizon-optifine`; G: `packs.rs` |
 | Agent control | L: `control.rs` (socket), `bin/horizon-ctl/`; G: `control.rs`, `agent.rs`, `events.rs`, `ui_control.rs` ([docs/agent-control.md](docs/agent-control.md)) |
 | Mods | crate `horizon-mods`; G: `mods.rs`; L: `mod_content.rs`, `mod_list.rs` |
-| Horizon extras, settings | L: `extras.rs`, `graphics.rs`, `settings.rs`, `minimap.rs`; G: `extras.rs` + `extras/` (each extra's glue: `mouse_tweaks.rs`, `sorting.rs`, `pvp.rs`, `reconnect.rs`), `options.rs` |
+| Horizon extras, settings | L: `extras.rs`, `graphics.rs`, `settings.rs`, `minimap.rs`; G: `extras.rs`, `tweaks.rs`, `options.rs` |

 ## How `Game` is organised

@@ -13,6 +13,14 @@ else (videos, Discord and other community material) lives elsewhere.
 suggest something. A pull request for a roadmap item carries its `roadmap:<id>` label; ideas go to the suggestion
 queue (the hub, or `/suggest` on Discord) rather than to issues, which are for bugs.

+**Mod-related pull requests go to [arismoko/horizon](https://github.com/arismoko/horizon)**, the fork that carries the
+mod API and reviews and merges that work. That covers the mod API, native hooks and events for mods, native mods,
+content mods (`.hmod`), mixins, wasm mods, `cargo horizon-mod`, `horizon-mods`, mod builds and the registry, and
+their docs ([mods](docs/mods.md), [native mods](docs/native-mods.md)). Open the pull request there from your usual
+branch. Mod-related pull requests opened here are closed with a pointer to it. Engine extension points that Horizon's
+own crates register (the [layer split](docs/layers.md)), resource and shader pack formats, and gameplay fixes stay
+here.
+
 ## Build it

 - **Prerequisites:** Rust (stable), Python 3.10+, JDK 25, and on Linux the ALSA and udev headers
@@ -190,3 +198,5 @@ new pushes, we add it again.

 [Discord](https://discord.gg/playhorizon) for questions and ideas, [issues](https://github.com/horizon-rust/horizon/issues)
 for bugs. To take something on, `/claim` its issue ([above](#claim-before-you-start)).
+
+How Horizon is run, and how people join the Team or lead a group: [GOVERNANCE.md](GOVERNANCE.md).
@@ -1418,6 +1418,7 @@ dependencies = [
 name = "horizon-chat-filter"
 version = "0.1.0"
 dependencies = [
+ "horizon-server-files",
 "serde",
 "serde_json",
 "toml",
@@ -1528,7 +1529,6 @@ dependencies = [
 "horizon-client-render",
 "horizon-command",
 "horizon-core",
- "horizon-friends",
 "horizon-hdr",
 "horizon-hooks",
 "horizon-items",
@@ -1592,7 +1592,6 @@ dependencies = [
 "horizon-optifine",
 "horizon-polytone",
 "horizon-protocol",
- "horizon-render-pipeline",
 "horizon-shader-api",
 "horizon-shaders",
 "horizon-system",
@@ -1651,6 +1650,15 @@ dependencies = [
 "ureq",
 ]

+[[package]]
+name = "horizon-discord"
+version = "0.1.0"
+dependencies = [
+ "horizon-platform",
+ "log",
+ "serde_json",
+]
+
 [[package]]
 name = "horizon-dualsense"
 version = "0.1.0"
@@ -1668,6 +1676,7 @@ dependencies = [
 "getrandom 0.3.4",
 "hkdf",
 "horizon-addresses",
+ "horizon-platform",
 "if-addrs",
 "serde",
 "serde_json",
@@ -1793,13 +1802,25 @@ dependencies = [
 name = "horizon-official"
 version = "0.1.0"
 dependencies = [
+ "horizon-discord",
+ "horizon-friends",
 "horizon-game",
 "horizon-heartbeat",
+ "horizon-official-servers",
 "horizon-platform",
 "log",
 "winresource",
 ]

+[[package]]
+name = "horizon-official-servers"
+version = "0.1.0"
+dependencies = [
+ "horizon-addresses",
+ "horizon-platform",
+ "log",
+]
+
 [[package]]
 name = "horizon-optifine"
 version = "0.1.0"
@@ -1891,10 +1912,6 @@ dependencies = [
 "ring",
 ]

-[[package]]
-name = "horizon-render-pipeline"
-version = "0.1.0"
-
 [[package]]
 name = "horizon-server"
 version = "0.1.0"
@@ -1957,7 +1974,6 @@ version = "0.1.0"
 dependencies = [
 "half",
 "horizon-core",
- "horizon-render-pipeline",
 "naga",
 "png",
 "zip",
@@ -34,6 +34,8 @@ members = [
    "crates/horizon-game",
    "crates/horizon-official",
    "crates/horizon-heartbeat",
+    "crates/horizon-discord",
+    "crates/horizon-official-servers",
    "crates/horizon-bench",
    "crates/horizon-friends",
    "crates/horizon-relay",
@@ -43,7 +45,6 @@ members = [
    "crates/cargo-horizon-mod",
    "crates/horizon-port-pack",
    "crates/horizon-shaders",
-    "crates/horizon-render-pipeline",
    "crates/horizon-optifine",
    "crates/horizon-polytone",
    "crates/horizon-shader-api",
@@ -0,0 +1,483 @@
+# Horizon governance
+
+> Adopted 2026-11-09 by the founder as his last decision as head of the project. It takes effect when he
+> announces that he is stepping down. From then on only the council changes it, by a 2/3 poll (section 15).
+
+Horizon has no boss. A **council of equals** decides by polls. **Theme groups** do the work in their areas, each
+with a **lead**. The **Horizon Team** reviews and merges code. **Moderators** keep the Discord server and the
+official server safe. Every role of trust is earned with work the project can measure, and it ends when that work
+stops.
+
+## Contents
+
+1. [Principles](#1-principles)
+2. [The levels at a glance](#2-the-levels-at-a-glance)
+3. [Each level in detail](#3-each-level-in-detail)
+4. [The council and its polls](#4-the-council-and-its-polls)
+5. [The selection filter](#5-the-selection-filter)
+6. [Theme groups](#6-theme-groups)
+7. [Moderation and appeals](#7-moderation-and-appeals)
+8. [Conflicts and hard cases](#8-conflicts-and-hard-cases)
+9. [The age rule (18+)](#9-the-age-rule-18)
+10. [The agents](#10-the-agents)
+11. [Accounts and the handover path](#11-accounts-and-the-handover-path)
+12. [Money](#12-money)
+13. [Transparency](#13-transparency)
+14. [Rules that are never voted on](#14-rules-that-are-never-voted-on)
+15. [Changing this document](#15-changing-this-document)
+
+## 1. Principles
+
+- **Equals.** Every council member has one vote. Nobody, the founder included, stands above the others.
+- **The founder.** Ludovic keeps the title of **Founder**: his role stays at the top of the member list and he is
+  credited as Horizon's founder everywhere. The title is symbolic. It carries no extra vote or power: on the council
+  he counts exactly like every other member.
+- **Evidence, not popularity.** You get a role by doing the work first. Kira measures that work: merged pull
+  requests, reviews, triage, support answers and days active. A vote then confirms it.
+- **Small, clear powers.** Each role can do a short, written list of things. Anything else goes to the council.
+- **Roles are on loan.** Every role has a 30-day probation and an inactivity rule. Stepping down for inactivity is
+  not a sanction, and you can come back.
+- **Public by default.** Polls, results and rules are public. Only matters about a person stay private, and even then
+  the result is published.
+- **18+ for roles of trust** (section 9).
+- **Mojang's and Microsoft's rules come first.** They are never put to a vote (section 14).
+
+## 2. The levels at a glance
+
+From the most open level to the most trusted. A person can hold several levels at once: a group lead can also be on
+the Horizon Team, for example.
+
+| Level | What it can do | How you get in | How you leave | 18+ |
+| --- | --- | --- | --- | --- |
+| **Member** | Play, chat, report bugs, suggest ideas, open issues and pull requests, pick group roles | Join the Discord server or the GitHub repo | Leave, or get banned | No |
+| **Contributor** (⛏️ Iron, 🥇 Gold, 💎 Diamond, 🟪 Netherite ranks) | Write in #contributors; `/claim` issues; nominate people for group lead (if active in that group) | One merged pull request in a public horizon-rust repo, linked with `/link-github` and `/verify-github`. Ranks come from merged pull requests: 10, 40, 100 and 200 | Contributor status and ranks stay | No |
+| **Group member** | Read and write in the group's channel; get the group's pings; take part in the group's advisory poll on its lead | Pick the group's role in Channels & Roles, or with `/groups` | Remove the role | No |
+| **🤝 Support** | Answer and close posts in #horizon-support | `/apply`; vote of the mods and the Team (as today) | Resign, 30 days inactive, or removed by the Chief of Mods or the council | No |
+| **🛡️ Moderator** | Time out, delete messages, manage threads, quarantine. No bans | `/apply`, then the selection filter; mods' vote; the council may object within 24 h | Resign, 30 days inactive, suspended by the Chief of Mods, removed by a council poll (simple majority) | **Yes** |
+| **🛡️ Chief of Mods** | A moderator's powers, plus bans; leads the mods; suspends a mod at once pending the council | Council poll (simple majority), from the mods with at least 30 days | Resign, 30 days inactive, council poll (simple majority) | **Yes** |
+| **🧭 Group lead** | Decides inside the group's topic (section 6); manages the group's channel; triage on the group's GitHub issues | Nomination, the filter, a 24 h public discussion with an advisory group poll, then a council poll (simple majority); 30 days probation | Resign, 30 days inactive (automatic), council poll (simple majority); confirmed again every 6 months | **Yes** |
+| **🌌 Horizon Team** | Review and merge pull requests (GitHub `horizon-team`, write access); `/nightly` and triage commands (trusted reviewers); #horizon-team | Nomination, the filter, a 24 h public discussion, then a council poll (2/3); 30 days probation | Resign, 60 days without a merge or review (automatic), council poll (2/3, without the person) | **Yes** |
+| **🏛️ Council** | Decides everything else by poll (section 4); bans; emergency actions by any 2 members | Nominated by a council member, the filter, a 24 h public discussion, then a council poll (2/3); 30 days probation | Resign, inactivity (section 5.5), council poll (2/3, without the person) | **Yes** |
+
+**The account holder** isn't a level. The founder (Ludovic) still holds the project's accounts (GitHub organisation
+owner, Discord server owner, the Microsoft app approved by Mojang, the domains, Railway, money). He carries out the
+council's decisions on them and hands them over step by step (section 11). As a council member he has one vote,
+like everyone else.
+
+## 3. Each level in detail
+
+### Member
+
+Anyone in the Discord server or on GitHub. Members follow the server rules and Horizon's
+[contributing guide](CONTRIBUTING.md). They can propose anything: an idea in #horizon-ideas, a bug in #horizon-bugs,
+an issue or a pull request on GitHub, or a request for a council poll (any council member can pick it up).
+
+### Contributor
+
+- **Discord:** the 🛠️ Contributor role writes in #contributors and in the threads of #polls-and-decisions. A rank
+  role (⛏️ Iron at 10 merged pull requests, 🥇 Gold at 40, 💎 Diamond at 100, 🟪 Netherite at 200, counted over every
+  public horizon-rust repo) shows how much has been merged. Ranks only go up.
+- **GitHub:** no repository role. Anyone can `/claim` and `/unclaim` their own issues.
+- **Alone:** their own work.
+
+### Group member
+
+Each theme group (section 6) has a role that anyone can pick and drop. It opens the group's channel and receives the
+group's pings. Picking a role grants no power. A group member counts as **active in the group** when Kira has seen at
+least one counted action in the group's area (section 5.1) in the last 60 days. Only active group members can
+nominate a lead or vote in the group's advisory poll.
+
+### 🤝 Support
+
+Unchanged: Support members help players in #horizon-support. They answer every post there and mark posts solved.
+The role carries no permission, so it has no age rule. They join through `/apply`, and the mods and the Team vote.
+
+### 🛡️ Moderators and the Chief of Mods
+
+- **Discord:** time out members, delete messages, manage threads and nicknames, read the audit log, quarantine
+  through Kira, and see the staff channels. **Moderators don't ban.** Bans are done by council members and the Chief of
+  Mods. Kira's automatic actions (the honeypot, clear scams, illegal images) stay as they are.
+- **Official server:** server operators (ops) are moderators in game. They need the 18+ rule and are confirmed the
+  same way (section 6, Server and SMP).
+- **Alone:** a timeout, a deleted message, a quarantine, with a reason in the mod case.
+- **The Chief of Mods** is the first contact for moderation questions. They organise the mods, can ban, and can take a
+  moderator's role away at once when there is a problem. The council confirms or reverses that within 72 hours.
+
+### 🧭 Group leads
+
+Section 6 says what a lead decides alone and what goes to the council.
+
+- **Discord:** in their group's channel only, delete messages, manage and pin threads, and ping the group role. The
+  🧭 lead role carries no server-wide permission.
+- **GitHub:** triage on the issues and pull requests that carry their group's label (`/label`, `/unlabel`, `/close`,
+  `/reopen`, `/unclaim`), from a list of group leads that grants no repository role. Leads merge only if they are on
+  the Horizon Team too.
+
+### 🌌 Horizon Team
+
+The Horizon Team **merges pull requests**. Its rules are in [the release flow](docs/release-flow.md): read the whole
+diff, never merge your own pull request, and use `needs-proof` for anything risky.
+
+- **GitHub:** member of the `horizon-team` team (write access to the Horizon repos), on the trusted reviewers list
+  (`/nightly` and triage commands).
+- **Discord:** the 🌌 Horizon Team role, #horizon-team, and writing in #contributors and the read-only channels.
+  Moderation permissions belong to the moderators and the council: a Team member moderates only if they also hold
+  one of those roles.
+- **During the 30-day probation:** they merge only ordinary pull requests. They don't merge `needs-proof` pull
+  requests, don't approve files that CODEOWNERS guards, and don't use `/nightly`.
+
+### 🏛️ Council
+
+- **Discord:** the 🏛️ Council role: the moderators' permissions plus ban and mention @everyone; #council (private);
+  starting polls in #polls-and-decisions.
+- **GitHub:** the `council` team. Over time it takes over the founder's CODEOWNERS review and his owner powers in the
+  release tools (section 11).
+- **Alone (any one member):** start a poll; pick up a member's request for a poll; do anything their other roles
+  allow.
+- **Any two members together:** an emergency action (section 4.6).
+- **Everything else** is decided by poll.
+
+## 4. The council and its polls
+
+### 4.1 Founding council
+
+kacpherek, levzzz5154, rdbtCVS, Online5277, dezer-x and Ludovic: six members, one vote each. The founding members
+don't go through the filter or a probation. They do make the 18+ declaration (section 9). The council has at most
+**9** members. It adds a seat only when a 2/3 poll says it needs one.
+
+### 4.2 How a poll works
+
+| Rule | Value |
+| --- | --- |
+| Who starts one | Any council member, with `/poll` (Kira). Anyone else asks a council member to start it |
+| Where | #polls-and-decisions, in public. Polls about a person (removal, appeals, the age rule) run in #council, and only their result is public |
+| How long | 24 hours. It closes early only if every council member has voted |
+| Ballot | Yes, No or Abstain. You can change it until the poll closes |
+| Quorum | At least half of the council votes (Abstain counts). With 6 members, 3 votes |
+| Simple majority | More Yes than No |
+| Two-thirds | Yes is at least 2/3 of the Yes and No votes, **and at least 3 Yes votes** |
+| Tie | Nothing changes |
+| No quorum | Nothing changes. Kira reminds the members who haven't voted 12 hours and 2 hours before the end |
+| About yourself | You don't vote, and you don't count in the council's size for that poll |
+| Asking again | A poll that failed can't be asked again for 7 days, unless two members agree that new facts justify it |
+
+### 4.3 Which threshold applies
+
+| Simple majority | Two-thirds |
+| --- | --- |
+| Day-to-day project decisions: direction, priorities, settling disputes between groups, a public statement | Adding council members and Horizon Team members |
+| Group leads and co-leads: appointing, removing, confirming every 6 months | Removing a council member or a Team member (without the person concerned) |
+| Moderators, the Chief of Mods, Support: confirming, removing | Rules: this document, the server rules, the contributing policy, the licence |
+| Ending a probation early | Money (section 12) |
+| Confirming an emergency action | Account handover steps (section 11) |
+| Second-level moderation appeals | Waiving part of the selection filter (section 5.4) |
+| Bringing back someone who stepped down for inactivity, within 6 months | Changing the council's size |
+
+**When in doubt, two-thirds.** Any council member can say a poll needs 2/3, and Kira then counts it at 2/3.
+
+### 4.4 Discussion
+
+Polls that add someone to the council, the Team or a lead post start with a **24-hour public discussion** (section
+5.3). Other polls are discussed in their own thread while they run. A member who wants more time votes No and says
+why. A failed poll can come back after 7 days.
+
+### 4.5 Conflicts of interest
+
+A member doesn't vote on a poll about themselves: their own role, their own removal, an appeal of their own
+moderation action, or money paid to them. They say so in the poll's thread and Kira leaves them out of the count.
+
+### 4.6 Emergencies
+
+For **security** (a leaked secret, a malicious pull request or mod, a hijacked account), **Mojang or Microsoft** (a
+request from them, a risk to the approved sign-in) or **legal** matters (a takedown, the law), **any two council
+members act at once**. They may:
+
+- pause releases and the Nightly;
+- take a mod down from the registry;
+- remove someone's roles or access for now;
+- lock or hide channels and content;
+- ask the account holder to rotate a secret or a key.
+
+They record it with `/emergency` in Kira, and both of them confirm it there. Kira opens a council poll at once
+(simple majority) to confirm it. If the poll doesn't pass, the action is undone where it can be. An emergency never
+adds members, changes rules or spends money.
+
+### 4.7 Removing a council member
+
+A 2/3 poll of the other members, in #council. The person concerned doesn't vote and doesn't count in the quorum.
+Only the result is published, never the reasons. Other ways to leave: resigning, inactivity (section 5.5), or a
+false age declaration (section 9).
+
+### 4.8 When the council drops below a quorum
+
+- **Fewer than 5 members:** Kira opens nominations for the council at once. The council fills seats within 30 days.
+- **Fewer than 3 members, or fewer than 3 who voted in the last 30 days:** an **interim council** forms. It counts the
+  remaining council members, the Horizon Team and the group leads past probation. Its only task is adding council
+  members, by its own 2/3 poll with a quorum of half. Any two of its members can take emergency actions. All other
+  decisions wait. The Team keeps merging and the leads keep leading.
+- **Nobody left:** the Team and the group leads form the interim council in the same way.
+
+## 5. The selection filter
+
+Nobody becomes a lead, a Team member or a council member just because they are well liked or talk a lot. Kira
+measures the work, and only people above a floor can be nominated. The council then decides among them.
+
+### 5.1 What Kira measures
+
+| Signal | What counts | Source |
+| --- | --- | --- |
+| **Merged pull requests** | Pull requests merged in a public horizon-rust repo. For Modding, also in the mod API's fork (arismoko/horizon). Counted overall, and per group by label or by files touched | GitHub search, as the ranks are counted today |
+| **Reviews** | Others' pull requests you reviewed: approved, asked for changes, or left a review with comments. One per pull request | GitHub search `reviewed-by:` and Kira's GitHub webhook |
+| **Triage** | Triage commands run (`/label`, `/close`, duplicates), issues labelled or closed, bug posts routed on Discord | The triage workflow's comments and Kira's webhook |
+| **Support answers** | #horizon-support posts you answered that ended solved | Kira's support feature |
+| **Active days** | Distinct days with any of the above, or with messages in #contributors or a group's channel. Chat elsewhere doesn't count | Kira |
+| **Tenure** | Days since your first counted contribution (since you joined the server, for moderators) | GitHub, Discord |
+| **Clean record** | No timeout, quarantine or ban in the last 90 days | Kira's mod cases |
+| **Verified GitHub** | `/verify-github` done | Kira |
+| **18+ declaration** | Made (section 9) | Kira |
+
+Kira turns these into an **evidence card**: the person's numbers, overall and in the group's area, for the last 60
+days and in total. Anyone can see their own card with `/evidence`. A nomination shows the card publicly.
+
+### 5.2 The floors
+
+A nomination is refused below these floors.
+
+| Role | Floor |
+| --- | --- |
+| **Group lead** | Verified GitHub; tenure of 30 days or more; **in the group's area: 8 or more merged pull requests, or 20 or more reviews** (Translations: 5 or more merged translation pull requests; Server and SMP: 8 pull requests, or 30 days as an official server operator with activity); 15 or more active days in the last 60; clean record; 18+ |
+| **Moderator** | In the server for 30 days or more; Kira level 10 or more; 15 or more active days in the last 60; clean record; 18+ |
+| **Chief of Mods** | Moderator for 30 days or more, past probation; 18+ |
+| **Horizon Team** | 🥇 Gold rank (40 merged pull requests); 20 or more reviews of others' pull requests; tenure of 30 days or more; 20 or more active days in the last 60; clean record; verified GitHub; 18+ |
+| **Council** | Horizon Team member, group lead or Chief of Mods for 60 days or more, past probation; 20 or more active days in the last 60; clean record; 18+ |
+
+The numbers are checked again once a year (section 15). They should stay reachable for people who really work on
+Horizon and out of reach for people who don't.
+
+### 5.3 The path to a role
+
+1. **Nomination.** Run `/nominate member: role: [group:]` in Kira.
+   - A **group lead** can be nominated by an active member of that group or by a council member. A self-nomination
+     needs a second from another active group member or a council member.
+   - A **Team member** can be nominated by a council or Team member. Someone can also nominate themselves with
+     `/apply`, if a council or Team member sponsors them.
+   - A **council member** can only be nominated by a council member.
+   - **Moderators** apply with `/apply`.
+2. **The filter.** Kira checks the floor and the 18+ declaration. Below the floor, Kira refuses and says which line
+   is short.
+3. **Public discussion, 24 hours.** Kira posts the nomination and the evidence card in a thread of
+   #polls-and-decisions. Contributors and the council can comment. For a lead, Kira also runs an **advisory poll** in
+   the group's channel for the same 24 hours. Only active group members vote in it, and the council sees the result.
+4. **Council poll, 24 hours.** Simple majority for a lead, 2/3 for the Team and the council. For moderators, the mods'
+   vote replaces this step, and any two council members can object within 24 hours; the council then decides by poll.
+5. **Probation, 30 days.** The role is held in full, except for the Team limits in section 3. At day 25, Kira asks the
+   council in #council whether anything is wrong. Probation ends by itself at day 30, unless a council poll (simple
+   majority) ended it earlier.
+
+### 5.4 Exceptions
+
+Some valuable people don't show up in the numbers, such as a designer for the website. The council can **waive the
+tenure or the area floors** by a 2/3 poll that says why. The age rule and the clean record are never waived.
+
+### 5.5 Inactivity
+
+Kira checks every day. It warns the person in a DM and in #council, then posts the step-down in
+#polls-and-decisions with neutral wording ("stepped down: inactive"), and removes the Discord role. The account
+holder or an org owner removes GitHub access when the Team role ends.
+
+| Role | What counts as activity | Warning | Steps down |
+| --- | --- | --- | --- |
+| Group lead | A counted action in the group's area, or messages in the group's channel | Day 21 | Day 30 |
+| Horizon Team | A merge or a review | Day 45 | Day 60 |
+| Moderator, Chief of Mods | A moderation action, or messages in the staff channels | Day 21 | Day 30 |
+| Support | An answer in #horizon-support | Day 21 | Day 30 |
+| Council | A vote in a poll. At 30 days with no vote, while at least 2 polls were held | Day 23 | Day 30, or 45 days with no counted activity at all |
+
+- **Away.** Anyone can announce an absence with `/away` for up to 45 days, once every 6 months. Away days don't
+  count. A lead names someone from the group to cover for them.
+- **Coming back.** Within 6 months: a simple-majority poll, with no new probation. After 6 months: the normal path.
+
+### 5.6 Terms
+
+- **Group leads** are confirmed every 6 months by a simple-majority poll. If someone else in the group passes the
+  floor and is nominated, both go on the same poll.
+- **Council and Team** have no fixed term. They stay as long as they are active and keep the council's trust. Removal
+  is always possible (section 4.7).
+
+## 6. Theme groups
+
+### 6.1 The groups
+
+| Group | Covers | GitHub | Discord |
+| --- | --- | --- | --- |
+| **Modding** | The mod API, native and content mods, mixins, the mod registry, `cargo horizon-mod` | The mod API lives in Ari's fork **arismoko/horizon**. Its owner runs that repo by their own rules; the council governs only what is Horizon's: horizon-rust/horizon-mods, horizon-mixins, horizon-native-mod-template, the registry. Label `mods` | The 🧩 MODDING category (#modding, #horizon-modding-team); roles 🧩 Modder (picked) and 🧩 Horizon Modding Team (the lead gives it) |
+| **Shaders and rendering** | The renderer, shaders, shader packs, OptiFine and Polytone pack formats | Label `rendering`; `crates/horizon-client-render` (gfx), `*.wgsl`, `horizon-shaders`, `horizon-shader-api`, `horizon-optifine`, `horizon-polytone` | #shaders-rendering |
+| **Performance** | Frame rate, memory, server tick, benchmarks | Label `perf`; `horizon-bench`, the benchmark tools | #performance |
+| **Launcher** | The launcher: installs, updates, instances, its pages | Label `launcher`; `launcher/` | #launcher |
+| **Server and SMP** | Dedicated server, hosting, the anticheat, multiplayer, and the official SMP | Labels `server`, `multiplayer`; `horizon-server*`, `horizon-anticheat`, `lan/`, `dedicated*`; horizon-rust/horizon-server | #server-smp (plus #join-server, #server-chat) |
+| **Translations** | The game's and the launcher's languages | Label `roadmap:languages`; `launcher/lang/`, `crates/horizon-client/assets/horizon/lang/` | #translations and the 🌍 language channels |
+| **Website** | playhorizon.dev | horizon-rust/horizon-site; label `website`. The site's design stays as it is unless the council decides otherwise | #website |
+| **Vanilla accuracy** | Parity with vanilla 26.3: harnesses, oracles, the port ledger | Labels `parity`, `parity-regression`, `full-parity`; `tools/test_*_parity.py`, the Java oracles | #vanilla-accuracy |
+| **UI** | The game's menus, HUD, settings, controller navigation, the design system | Labels `ui`, `accessibility`; `title/`, `settings_shell.rs`, `hud*`, `ui.rs`, `docs/design-system.md`, `horizon-theme`. The launcher's look is shared with Launcher | #ui |
+
+A pull request can belong to two groups. Both leads can comment, and the Team merges as usual. If the leads disagree,
+the council decides.
+
+### 6.2 Leads per group
+
+- **One lead per group.** A group with 8 or more active members may also have **one co-lead**, chosen the same way.
+- A person leads **at most two groups**. Council members may lead a group, though a lead from outside the council is
+  preferred: it spreads the work.
+
+### 6.3 What a lead decides alone
+
+Inside their group's topic, and within this document, the contributing guide, the vanilla-first rule, the layers and
+the design system:
+
+- the group's priorities and the order of its roadmap items;
+- which issues are `good first issue`, and triage of the group's issues;
+- technical and design direction inside the area, when vanilla behaviour and the default look don't change;
+- accepting or declining an idea or a proposal in the area. Any two active group members or one council member can
+  take that decision to the council;
+- how the group organises itself (threads, meetings, the channel's rules on top of the server's);
+- asking the Team for reviews, adding `needs-proof`, and nominating people.
+
+### 6.4 What goes to the council
+
+- the rules, money, accounts and secrets;
+- who is on the council, the Team or the mods;
+- anything that changes vanilla behaviour or turns a Horizon-only feature on by default;
+- breaking a public promise: the mod API, server compatibility, save and file formats;
+- disputes between groups;
+- anything involving Mojang, Microsoft or the law;
+- speaking for the whole project outside the group's topic.
+
+### 6.5 A group without a lead
+
+The work goes on. The Team reviews and merges, and Kira still routes the group's issues and questions to its
+channel. Until a lead is chosen, any council member may take a lead's decision for that group and says so in the
+channel. Kira pins a "lead wanted" note with the floor. **No lead is better than a lead who doesn't do the work:**
+nobody is appointed just to fill the seat.
+
+## 7. Moderation and appeals
+
+- **The server rules** are in #rules. Moderators enforce them, the Chief of Mods leads the mods, and the council can
+  change the rules (2/3).
+- **Every action has a mod case**: who acted, what they did, and why. Kira keeps the cases.
+- **First appeal:** within 14 days, through #appeal (for a quarantine) or mod mail. A moderator who wasn't involved,
+  or the Chief of Mods, answers within 72 hours.
+- **Second appeal:** for bans, timeouts over 24 hours and quarantines, a council poll in #council (simple majority).
+  Members who were involved don't vote. The answer is final for 90 days.
+- **Not appealable here:** actions that Discord's rules or the law require. Those are reported where the law says.
+- **Removing a moderator:** the Chief of Mods can suspend a moderator at once, and the council decides within 72 hours
+  (simple majority). The council removes the Chief of Mods the same way.
+- **Staff are moderated like everyone.** When a council member is involved, the council decides without them.
+
+## 8. Conflicts and hard cases
+
+| Case | What happens |
+| --- | --- |
+| Two groups disagree | The leads talk first. If they still disagree, the council decides (simple majority) |
+| A lead's decision is contested | Any two active group members or one council member can bring it to the council |
+| A Team member merges against the rules | Any council member can revert the merge. The council can remove the member (2/3) |
+| A council member breaks the rules | The council decides without them. Removal takes 2/3 (section 4.7) |
+| Someone holds a role and is under 18 | Section 9 |
+| The council can't reach quorum | Section 4.8 |
+| The founder and the council disagree about one of his own accounts | Until a step of section 11 hands it over, the account stays his. He carries out the council's decisions on project matters, or he says publicly that he won't |
+
+## 9. The age rule (18+)
+
+**Who must be 18 or older:** members of the council and the Horizon Team, trusted reviewers, group leads and
+co-leads, the Chief of Mods and the moderators, official server operators, and anyone with admin rights anywhere in
+the project: Discord (Administrator, Manage Roles, Manage Channels, ban), GitHub (write, admin, organisation),
+server panels, Railway, or Kira's admin side. The same goes for anyone who holds a project secret.
+
+**Who doesn't have to be:** members, contributors (with any rank), group members and 🤝 Support. Contributors under
+18 are welcome and valued. They just can't hold the roles above.
+
+**How it's checked, without collecting ID:**
+
+- **A declaration.** Before taking such a role, and once at the start for everyone who holds one, the person presses
+  a button in Kira: "I confirm that I am 18 or older. I understand that a false declaration removes all my roles of
+  trust." Kira keeps only the Discord account, the date and the wording's version. It never stores a birth date, an
+  ID, a photo, or any outside age-checking service's result.
+- **No declaration, no role.** At the start, current role holders have 7 days to make it. Until they do, their role is
+  paused.
+- **When there's doubt** (the person says they are younger, or there is a credible private report), one council
+  member asks the person privately. If the doubt remains, any council member pauses the role, and the council decides
+  within 72 hours in #council.
+- **A false declaration** removes every role of trust at once, and the person can't hold one for 12 months.
+- **Privacy.** Age is never discussed in public. A role that ends for this reason ends with the same neutral line as
+  any other step-down.
+
+## 10. The agents
+
+Horizon uses AI agents: the founder's orchestrator, which runs coding agents, and Kira, the Discord bot.
+
+- **They obey council decisions only:** a passed poll recorded by Kira, a recorded emergency action of two council
+  members, and the standing rules in this document and the project's docs.
+- **The only exception is the founder's own things:** his spending, his machines (they run CI and the vanilla tests),
+  his personal accounts and his time. On those, his word decides. This list should get shorter over time (section 11).
+- **Role work isn't a decision.** A lead asking Kira to route issues, or a Team member asking an agent to prove a pull
+  request, is that person using their role. The agents help, within the role's powers.
+- **They check the source.** An agent acts on a decision only when it finds it in Kira's decisions log
+  (section 13). A message saying "the council decided", or a screenshot, is not enough.
+- **They post as agents.** Everything an agent posts says it comes from an agent, and states decisions as the
+  project's.
+
+## 11. Accounts and the handover path
+
+Today the founder holds every account. The aim is for him to hold fewer, in an order that never leaves the project
+unable to act, and never puts an account that is tied to a person into anyone else's hands.
+
+| Account | Today | Can it be shared? | Plan |
+| --- | --- | --- | --- |
+| **GitHub organisation** (horizon-rust) | One owner (the founder) | Yes: an organisation can have several owners | **Step 1:** a second owner from the council, chosen by a 2/3 poll in the council's first week, with two-factor authentication on. **Step 2:** a `council` team; CODEOWNERS reviews and the release tools' owner powers (`paused`, `/nightly remove`) move from the founder to that team |
+| **Discord server** | Owned by the founder | Partly: a server has exactly one owner; powers can be given through roles | **Step 1:** the 🏛️ Council role gets moderation and ban permissions; Kira applies the outcomes of passed polls, so nobody needs Manage Roles; two-factor authentication becomes required for moderation. Ownership itself stays with the founder until a legal entity exists |
+| **Kira** (bot application, Railway service) | The founder's Discord developer account and Railway | The bot: yes (a Discord developer team). Railway: adding members may need a paid plan | **Step 1:** a Discord developer team with two council members. Railway members once the council decides on money |
+| **Official server** (hosting panel) | The founder's account | Yes: panel sub-users | **Step 1:** sub-users for the Server and SMP lead and for one council member |
+| **Domains** (playhorizon.dev and the others) | The founder's registrar account | Not without moving it | Auto-renewal on, registered for several years ahead. They move only to a legal entity, if one is created |
+| **The Microsoft app approved by Mojang** (sign-in) | The founder's Azure app registration; Mojang approved it after his application | **No.** The approval was given on his application. Moving the app or adding owners would change who Mojang deals with, and we have found no documented way to transfer an approval | **Never moves** without Mojang's written agreement. The only change considered: a legal entity, if one is created, and only if Mojang agrees |
+| **Signing** (Apple developer certificate, release signing keys) | The founder's | The Apple certificate is in his legal name: no | The Apple certificate never moves. Release keys stay in GitHub's protected environments, and the council team approves their use from step 2 |
+| **Money** (sponsorship, donations) | Personal accounts of the founder | Through a fiscal host | Section 12 |
+| **The founder's machines, AI accounts and password vault** | His | No | His own things: they never move. The project should depend on them less over time |
+
+**Order:** first the safety nets that remove a single point of failure (a second organisation owner, the bot's
+developer team, panel sub-users). Then the day-to-day powers (CODEOWNERS and release tools to the council team). Last,
+whatever needs a legal entity: domains, money, and with Mojang's agreement the sign-in app. Each step is a 2/3 poll,
+and the founder carries it out.
+
+## 12. Money
+
+*Placeholder: the options (Open Collective and others) are being researched.*
+
+- The council approves every expense by a **2/3 poll**.
+- **Every income and every expense is public.**
+- Nobody votes on money paid to themselves.
+
+## 13. Transparency
+
+- **#polls-and-decisions:** every poll and every result, posted by Kira, and the 24-hour discussions of nominations.
+  For polls that aren't about a person, each member's vote is shown once the poll closes.
+- **The decisions log:** Kira keeps an append-only record of every poll, emergency action, appointment and
+  step-down, with its date and result. It is public and machine-readable, so the agents can check a decision there.
+- **This document** lives in horizon-rust/horizon as `GOVERNANCE.md`. A short summary is pinned in #rules and in
+  #polls-and-decisions.
+- **Who holds which role:** the people page of playhorizon.dev's hub shows the council, the Team, the group leads,
+  the Chief of Mods, the moderators and Support.
+- **#council** is private for discussion and for polls about people. Everything the council decides is published.
+
+## 14. Rules that are never voted on
+
+These are Horizon's conditions for existing, not choices. No poll can change them:
+
+- Playing needs a **Microsoft account that owns Minecraft: Java Edition**. There is no play without one.
+- **No Mojang files** in Horizon's repos or downloads. Players' own copies stay on their own machines.
+- **No gambling**, in any form, including with in-game currency.
+- **Mojang's and Microsoft's terms and Usage Guidelines** apply to everything Horizon does.
+- **The law**, and the terms of service of Discord and GitHub.
+
+## 15. Changing this document
+
+A 2/3 council poll, then a pull request that a Team member merges. The council reviews the floors' numbers
+(section 5.2) once a year, or sooner if they turn out wrong.
@@ -135,6 +135,8 @@ python3 tools/pr_ready.py

 It runs rustfmt, clippy, the touched crates' tests, the Python tests, the public-tree check and the vanilla harnesses your change affects. Never commit game files, decompiled source or prepared resources.

+How Horizon is run (the council, theme groups and their leads, the Horizon Team, moderation): [GOVERNANCE.md](GOVERNANCE.md).
+
 ## Project status

 **Player-visible gaps: 0 open** of the 833 the [port ledger](tools/port_ledger.py) found, reading every vanilla 26.3 method against Horizon's code: vanilla behaviour a player would notice that Horizon doesn't have yet. By area: Animals [0](https://github.com/horizon-rust/horizon/issues/3512); Monsters and bosses [0](https://github.com/horizon-rust/horizon/issues/3513); Entities, projectiles, vehicles and decorations [0](https://github.com/horizon-rust/horizon/issues/3514); Items, enchantments and inventories [0](https://github.com/horizon-rust/horizon/issues/3515); Blocks, redstone and fluids [0](https://github.com/horizon-rust/horizon/issues/3516); World, world generation and saves [0](https://github.com/horizon-rust/horizon/issues/3517); Screens, HUD and client packets [0](https://github.com/horizon-rust/horizon/issues/3518); Entity and block rendering, models [0](https://github.com/horizon-rust/horizon/issues/3519); Server and players on the server [0](https://github.com/horizon-rust/horizon/issues/3520); Mob AI, villagers and raids [0](https://github.com/horizon-rust/horizon/issues/3521). This number goes down as gaps close (`tools/parity_gaps.py`); the table below says what the harnesses compare.
@@ -15,6 +15,10 @@ pub const OFFICIAL_SERVER: &str = "play.playhorizon.dev";
 /// `official_server_previous` in `launcher/links.json`).
 pub const OFFICIAL_SERVER_PREVIOUS: &[&str] = &["horizon.bunchy7s.dev"];

+/// Afri-Network, a partner server the game added once below the official server (#9299) until
+/// the partnership ended: kept so the game can take back out the entry it added.
+pub const WITHDRAWN_PARTNER_SERVER: &str = "afri-network.co.za";
+
 /// [`OFFICIAL_SERVER`] with the port its SRV record gives, for askers that don't look SRV up
 /// (the telemetry server's status checks).
 pub const OFFICIAL_SERVER_STATUS: &str = "play.playhorizon.dev:24454";
@@ -7,6 +7,8 @@ rust-version.workspace = true
 description = "The dedicated server's chat filter: its [chat_filter] settings, the slur list's matcher and the mutes, with no game state (docs/chat-filter.md)"

 [dependencies]
+# The moderation durations, shared with `/tempban`.
+horizon-server-files = { path = "../horizon-server-files" }
 serde = { version = "1", features = ["derive"] }
 serde_json = "1"
 toml = "1.1"
@@ -10,6 +10,9 @@ use std::path::{Path, PathBuf};

 mod normalise;

+pub use horizon_server_files::duration::{
+    DurationUnit, duration_parts, duration_text, now_millis, parse_duration,
+};
 pub use normalise::{Run, Text};

 /// The list built into the game, used when `words_file` is empty.
@@ -474,61 +477,6 @@ pub fn append_log(path: &Path, line: &str) -> std::io::Result<()> {
    writeln!(f, "{line}")
 }

-/// `/tempmute`'s duration in milliseconds: a positive whole number and a unit, `s`, `m`, `h`, `d` or
-/// `w` (`10m`, `2h`, `1d`).
-pub fn parse_duration(text: &str) -> Option<i64> {
-    let unit = match text.chars().last()? {
-        's' => 1_000,
-        'm' => MINUTE,
-        'h' => 60 * MINUTE,
-        'd' => 24 * 60 * MINUTE,
-        'w' => 7 * 24 * 60 * MINUTE,
-        _ => return None,
-    };
-    let count: i64 = text[..text.len() - 1].parse().ok()?;
-    (count > 0).then(|| count.checked_mul(unit)).flatten()
-}
-
-/// The unit used when presenting a moderation duration to a player.
-#[derive(Clone, Copy, Debug, PartialEq, Eq)]
-pub enum DurationUnit {
-    Minute,
-    Hour,
-    Day,
-}
-
-/// A duration's rounded count and unit, shared by logs and translated replies.
-pub fn duration_parts(millis: i64) -> (i64, DurationUnit) {
-    let (unit, kind) = if millis <= 60 * MINUTE {
-        (MINUTE, DurationUnit::Minute)
-    } else if millis <= 48 * 60 * MINUTE {
-        (60 * MINUTE, DurationUnit::Hour)
-    } else {
-        (24 * 60 * MINUTE, DurationUnit::Day)
-    };
-    (
-        millis.div_euclid(unit) + i64::from(millis.rem_euclid(unit) > 0),
-        kind,
-    )
-}
-
-/// `millis` for logs, rounded up: minutes up to an hour, hours up to two days, then days.
-pub fn duration_text(millis: i64) -> String {
-    let (count, unit) = duration_parts(millis);
-    let unit = match unit {
-        DurationUnit::Minute => "minute",
-        DurationUnit::Hour => "hour",
-        DurationUnit::Day => "day",
-    };
-    format!("{count} {unit}{}", if count == 1 { "" } else { "s" })
-}
-
-pub fn now_millis() -> i64 {
-    std::time::SystemTime::now()
-        .duration_since(std::time::UNIX_EPOCH)
-        .map_or(0, |d| d.as_millis() as i64)
-}
-
 /// `YYYY-MM-DDTHH:MM:SSZ` for epoch milliseconds.
 pub fn utc(millis: i64) -> String {
    let secs = millis.div_euclid(1000);
@@ -9,11 +9,13 @@ description = "The client's input layer: key bindings and their names, mouse, co
 [dependencies]
 horizon-client-core = { path = "../horizon-client-core" }
 winit = "0.30.13"
-# The window icon.
-horizon-theme = { path = "../horizon-theme" }
 png = "0.18"
 arboard = { version = "3.6.1", default-features = false, features = ["wayland-data-control"] }

+[dev-dependencies]
+# The window icon test decodes Horizon's icon.
+horizon-theme = { path = "../horizon-theme" }
+
 [features]
 controllers = []

@@ -98,6 +98,7 @@ actions! {
    Emote, "key.emote", Some(KeyCode::KeyB);
    HotbarPrevious, "pad.hotbarPrevious", None;
    HotbarNext, "pad.hotbarNext", None;
+    Radial, "pad.radial", None;
 }

 impl Action {
@@ -253,6 +253,17 @@ impl Activity {
 /// Horizon's pad-only actions (no vanilla key mapping).
 pub const HOTBAR_PREVIOUS: &str = "pad.hotbarPrevious";
 pub const HOTBAR_NEXT: &str = "pad.hotbarNext";
+/// Held, opens the radial menu (`radial.rs`).
+pub const RADIAL: &str = "pad.radial";
+
+mod radial_file;
+pub use radial_file::{RadialMode, RadialStick, opener_refused};
+
+/// The `bindLayout` the settings file is written in. 1: the defaults of the binds list as they
+/// are; 2: the radial menu's opener resolved against the player's own buttons.
+const BIND_LAYOUT: u32 = 2;
+/// The layout from which the file, not the default, says where the opener is.
+const OPENER_LAYOUT: u32 = 2;

 /// Bindable actions and their default buttons: vanilla key mappings (the
 /// game acts as their default key) and Horizon's pad-only actions. Start is
@@ -271,6 +282,7 @@ pub const ACTIONS: &[(&str, Option<Button>)] = &[
    ("key.togglePerspective", Some(Button::Select)),
    ("key.pickItem", Some(Button::DPadLeft)),
    ("key.chat", Some(Button::DPadUp)),
+    (RADIAL, Some(Button::DPadRight)),
    ("key.advancements", None),
    ("key.playerlist", None),
    ("key.command", None),
@@ -303,11 +315,14 @@ pub enum Route {
    HotbarStep {
        next: bool,
    },
+    Radial,
    /// Held, or flipped when the pad's toggle sneak is on.
    Sneak,
    Screenshot,
    SmoothCamera,
    Fullscreen,
+    /// F3's debug screen, shown or hidden as F3 alone does.
+    DebugOverlay,
    /// Does nothing by itself: what reads it asks whether the button is held
    /// (`Minecraft.handleKeybinds`' toolbar keys, held with a hotbar key).
    Held,
@@ -320,10 +335,12 @@ pub fn route(action: &str) -> Option<Route> {
    match action {
        HOTBAR_PREVIOUS => Some(Route::HotbarStep { next: false }),
        HOTBAR_NEXT => Some(Route::HotbarStep { next: true }),
+        RADIAL => Some(Route::Radial),
        "key.sneak" => Some(Route::Sneak),
        "key.screenshot" => Some(Route::Screenshot),
        "key.smoothCamera" => Some(Route::SmoothCamera),
        "key.fullscreen" => Some(Route::Fullscreen),
+        "key.debug.overlay" => Some(Route::DebugOverlay),
        "key.saveToolbarActivator" | "key.loadToolbarActivator" => Some(Route::Held),
        _ => {
            let default = crate::keybinds::KeyBinds::default_of(action);
@@ -334,12 +351,16 @@ pub fn route(action: &str) -> Option<Route> {
    }
 }

+/// The radial menu's opener, as the binds list and the gameplay guide name it.
+pub const RADIAL_CAPTION: &str = "horizon.pad.action.radial";
+
 /// An action's name in the binds list: vanilla's translation key, or
 /// Horizon's own English for the pad-only actions.
 pub fn action_caption(action: &str) -> &str {
    match action {
        HOTBAR_PREVIOUS => "Hotbar: Previous Slot",
        HOTBAR_NEXT => "Hotbar: Next Slot",
+        RADIAL => RADIAL_CAPTION,
        other => other,
    }
 }
@@ -654,6 +675,21 @@ pub struct PadSettings {
    pub repeat_interval: f32,
    /// Action name -> button, `None` for unbound; missing means the default.
    bindings: BTreeMap<&'static str, Option<Button>>,
+    /// The radial menu's pages.
+    pub radial: crate::radial::Pages,
+    /// Whether the radial menu's opener is held or pressed once.
+    pub radial_mode: RadialMode,
+    /// The stick that selects in it.
+    pub radial_stick: RadialStick,
+    /// Lines this game doesn't read (a newer Horizon's settings, an action it doesn't have, a
+    /// button it doesn't know), kept as they were so a save here loses nothing.
+    extra: Vec<(String, String)>,
+    /// The newest `bindLayout` the file has been written in: this game's, or a newer Horizon's,
+    /// kept so that one doesn't resolve its file again as older than it is.
+    bind_layout: u32,
+    /// The opener last used with each stick (`RadialStick::ALL` order), so stepping the Selects
+    /// With row and back gives each stick's own opener again.
+    openers: radial_file::StickOpeners,
 }
 impl Default for PadSettings {
    fn default() -> Self {
@@ -680,6 +716,12 @@ impl Default for PadSettings {
            repeat_delay: 0.35,
            repeat_interval: 0.09,
            bindings: BTreeMap::new(),
+            radial: Default::default(),
+            radial_mode: RadialMode::Hold,
+            radial_stick: RadialStick::Right,
+            extra: Vec::new(),
+            bind_layout: BIND_LAYOUT,
+            openers: radial_file::StickOpeners::default(),
        }
    }
 }
@@ -706,6 +748,7 @@ impl PadSettings {
    }
    pub fn parse(text: &str) -> Self {
        let mut s = Self::default();
+        let mut saved_opener = None;
        for line in text.lines() {
            let Some((key, value)) = line.split_once(':') else {
                continue;
@@ -754,22 +797,85 @@ impl PadSettings {
                "scrollSpeed" => s.scroll_speed = bounded(s.scroll_speed, 1.0, 36.0),
                "repeatDelay" => s.repeat_delay = bounded(s.repeat_delay, 0.1, 1.0),
                "repeatInterval" => s.repeat_interval = bounded(s.repeat_interval, 0.03, 0.3),
+                "radialMode" => s.radial_mode = RadialMode::parse(value),
+                "radialStick" => s.radial_stick = RadialStick::parse(value),
+                // Read after the loop, from the whole text.
+                "bindLayout" => {}
+                // The radial menu's pages (`radial::Pages::parse`).
+                other if other.starts_with("radial_") || other == crate::radial::LAYOUT_KEY => {}
                other => {
-                    if let Some(action) = other.strip_prefix("bind_") {
-                        let button = if value == "none" {
-                            Some(None)
-                        } else {
-                            Button::parse(value).map(Some)
-                        };
-                        if let Some(button) = button {
-                            s.bind(action, button);
-                        }
+                    let known = other
+                        .strip_prefix("bind_")
+                        .filter(|action| ACTIONS.iter().any(|a| a.0 == *action));
+                    let button = if value == "none" {
+                        Some(None)
+                    } else {
+                        Button::parse(value).map(Some)
+                    };
+                    match (known, button) {
+                        // The opener once the selecting stick is known.
+                        (Some(RADIAL), Some(button)) => saved_opener = Some(button),
+                        (Some(action), Some(button)) => s.bind(action, button),
+                        _ => s.extra.push((other.to_owned(), value.to_owned())),
                    }
                }
            }
        }
-        // A file from before these defaults: its player's buttons stay where they were.
-        if !text.is_empty() && !text.lines().any(|line| line.starts_with("bindLayout:")) {
+        // An opener on a button it can't be with this stick reads as never saved.
+        let refused_opener = match saved_opener {
+            Some(Some(b)) if opener_refused(s.radial_stick, b) => true,
+            Some(button) => {
+                s.bind(RADIAL, button);
+                false
+            }
+            None => false,
+        };
+        if let Some(pages) = crate::radial::Pages::parse(
+            text.lines()
+                .filter_map(|line| line.split_once(':'))
+                .map(|(key, value)| (key.trim(), value.trim())),
+        ) {
+            s.radial = pages;
+        }
+        let lines = || text.lines().map(str::trim);
+        let saved = |action: &str| {
+            let prefix = format!("bind_{action}:");
+            lines().any(|line| line.starts_with(&prefix))
+        };
+        // The layout the file was written in; none in a file from before these defaults.
+        let layout = lines()
+            .find_map(|line| line.strip_prefix("bindLayout:"))
+            .map(|value| value.trim().parse::<u32>().unwrap_or(0));
+        s.bind_layout = layout.map_or(BIND_LAYOUT, |layout| layout.max(BIND_LAYOUT));
+        // Once, for a file from before the radial menu's opener, or one with the opener on a
+        // button it can no longer be: a button the player bound by hand stays theirs, and the
+        // opener's default doesn't take it. From then on the file says where the opener is, and
+        // a conflict made since stays shown in the binds list.
+        let before_opener = layout.is_none_or(|layout| layout < OPENER_LAYOUT);
+        if !text.is_empty() && (refused_opener || (before_opener && !saved(RADIAL))) {
+            let default_opener = ACTIONS
+                .iter()
+                .find(|(action, _)| *action == RADIAL)
+                .and_then(|(_, button)| *button);
+            let taken = s.bindings.iter().any(|(action, button)| {
+                *action != RADIAL && button.is_some() && *button == default_opener
+            });
+            if taken {
+                s.bindings.insert(RADIAL, None);
+            }
+        }
+        // The default too can be under the selecting thumb (D-pad Right, the left stick
+        // selecting): no button opens the menu until the player picks one.
+        if s.binding(RADIAL)
+            .is_some_and(|b| opener_refused(s.radial_stick, b))
+        {
+            s.bindings.insert(RADIAL, None);
+        }
+        // A file from before these defaults: its player's buttons stay where they were, and
+        // nothing they saved shares a button with the radial menu's opener. They can bind one
+        // in the binds list.
+        if !text.is_empty() && layout.is_none() {
+            s.bindings.entry(RADIAL).or_insert(None);
            for (action, button) in [
                ("key.drop", Button::East),
                ("key.togglePerspective", Button::DPadUp),
@@ -778,10 +884,7 @@ impl PadSettings {
                ("key.advancements", Button::DPadDown),
            ] {
                // A button saved by hand stays, even one that's now this action's default.
-                if !text
-                    .lines()
-                    .any(|line| line.starts_with(&format!("bind_{action}:")))
-                {
+                if !saved(action) {
                    s.bindings.entry(action).or_insert(Some(button));
                }
            }
@@ -822,7 +925,25 @@ impl PadSettings {
            "playInBackground:{}\n",
            bool_text(self.play_in_background)
        ));
-        text.push_str("bindLayout:1\n");
+        text.push_str(&format!(
+            "radialMode:{}\nradialStick:{}\n",
+            self.radial_mode.name(),
+            self.radial_stick.name()
+        ));
+        text.push_str(&format!("bindLayout:{}\n", self.bind_layout));
+        for (key, value) in &self.extra {
+            // A button this game didn't know, for an action the player has bound here since.
+            let rebound = key
+                .strip_prefix("bind_")
+                .is_some_and(|action| self.bindings.contains_key(action));
+            if !rebound {
+                text.push_str(&format!("{key}:{value}\n"));
+            }
+        }
+        // The default pages aren't written: they can improve for a player who never changed them.
+        if self.radial != crate::radial::Pages::default() {
+            text.push_str(&self.radial.serialize());
+        }
        text
    }
    pub fn default_of(action: &str) -> Option<Button> {
@@ -835,11 +956,15 @@ impl PadSettings {
            None => Self::default_of(action),
        }
    }
-    /// Bind an action (`None` unbinds); unknown actions are ignored.
+    /// Put `action` on `button`, or unbind it. An unknown action, or a button it can't take
+    /// (`can_bind`), changes nothing.
    pub fn bind(&mut self, action: &str, button: Option<Button>) {
        let Some((name, default)) = ACTIONS.iter().find(|a| a.0 == action) else {
            return;
        };
+        if button.is_some_and(|b| !self.can_bind(action, b)) {
+            return;
+        }
        if button == *default {
            self.bindings.remove(name);
        } else {
@@ -1440,6 +1565,24 @@ pub enum Rumble {
        radius: f32,
    },
    Totem,
+    /// The radial menu's stick reached a slot that would run: a tick.
+    RadialSlot,
+    /// The radial menu's page turned: a shorter tick.
+    RadialPage,
+    /// The page turn went round an end: a second tick after the first.
+    RadialWrap,
+    /// A release ran nothing after something had been selected: a soft buzz.
+    RadialNothing,
+}
+impl From<crate::input_source::Feedback> for Rumble {
+    fn from(event: crate::input_source::Feedback) -> Self {
+        use crate::input_source::Feedback;
+        match event {
+            Feedback::BlockBroken => Rumble::BlockBroken,
+            Feedback::Explosion { distance, radius } => Rumble::Explosion { distance, radius },
+            Feedback::Totem => Rumble::Totem,
+        }
+    }
 }
 /// A vibration: the heavy (low-frequency) and light motors, 0..1, and how
 /// long it lasts.
@@ -1449,6 +1592,7 @@ pub struct Pulse {
    pub weak: f32,
    pub millis: u32,
 }
+use crate::radial::{RADIAL_NOTHING, RADIAL_PAGE_TICK, RADIAL_TICK};
 impl Rumble {
    pub fn name(self) -> &'static str {
        match self {
@@ -1456,6 +1600,10 @@ impl Rumble {
            Rumble::BlockBroken => "block",
            Rumble::Explosion { .. } => "explosion",
            Rumble::Totem => "totem",
+            Rumble::RadialSlot => "radial",
+            Rumble::RadialPage => "radial_page",
+            Rumble::RadialWrap => "radial_wrap",
+            Rumble::RadialNothing => "radial_nothing",
        }
    }
    /// The pulse, or `None` when it is too faint to feel.
@@ -1482,6 +1630,9 @@ impl Rumble {
                    millis: 350,
                })
            }
+            Rumble::RadialSlot => Some(RADIAL_TICK),
+            Rumble::RadialPage | Rumble::RadialWrap => Some(RADIAL_PAGE_TICK),
+            Rumble::RadialNothing => Some(RADIAL_NOTHING),
            Rumble::Totem => Some(Pulse {
                strong: 0.7,
                weak: 0.7,
@@ -1503,6 +1654,10 @@ impl Rumble {
        };
        match self {
            Rumble::BlockBroken => vec![Pulse { millis: 35, ..p }],
+            Rumble::RadialSlot
+            | Rumble::RadialPage
+            | Rumble::RadialWrap
+            | Rumble::RadialNothing => vec![p],
            Rumble::Hurt(_) => {
                let tail = p.millis.saturating_sub(50) / 2;
                vec![step(1.0, 50), step(0.55, tail), step(0.25, tail)]
@@ -1863,7 +2018,55 @@ bind_key.hotbar.2:north
        let odd = PadSettings::parse(
            "lookSensitivity:NaN\nbind_key.nope:south\nbind_key.jump:x9\nbindLayout:1\n",
        );
-        assert_eq!(odd, PadSettings::default());
+        assert_eq!(
+            odd.look_sensitivity,
+            PadSettings::default().look_sensitivity
+        );
+        assert_eq!(odd.binding("key.jump"), Some(Button::South));
+        assert_eq!(odd.actions_of(Button::South), ["key.jump"]);
+    }
+
+    #[test]
+    fn lines_this_game_doesnt_read_survive_a_save() {
+        // A newer Horizon's setting, an action this game doesn't have, a button it doesn't know.
+        let text =
+            "bindLayout:2\nhapticStrength:0.4\nbind_horizon:dash:south\nbind_key.jump:paddle1\n";
+        let s = PadSettings::parse(text);
+        assert_eq!(
+            s.binding("key.jump"),
+            Some(Button::South),
+            "the default meanwhile"
+        );
+        let saved = s.serialize();
+        for line in [
+            "hapticStrength:0.4\n",
+            "bind_horizon:dash:south\n",
+            "bind_key.jump:paddle1\n",
+        ] {
+            assert!(saved.contains(line), "{line} lost from\n{saved}");
+        }
+        assert_eq!(PadSettings::parse(&saved), s);
+        // Bound here since, the action's own line is the one written.
+        let mut s = s;
+        s.bind("key.jump", Some(Button::West));
+        let saved = s.serialize();
+        assert!(!saved.contains("paddle1"), "{saved}");
+        assert_eq!(
+            PadSettings::parse(&saved).binding("key.jump"),
+            Some(Button::West)
+        );
+    }
+
+    #[test]
+    fn a_newer_bind_layout_is_kept() {
+        let newer = BIND_LAYOUT + 1;
+        let s = PadSettings::parse(&format!("bindLayout:{newer}\nvibration:false\n"));
+        assert!(s.serialize().contains(&format!("bindLayout:{newer}\n")));
+        let s = PadSettings::parse("bindLayout:1\nvibration:false\n");
+        assert!(
+            s.serialize()
+                .contains(&format!("bindLayout:{BIND_LAYOUT}\n"))
+        );
    }

    #[test]
@@ -0,0 +1,354 @@
+//! The radial menu's settings in the controller file (`horizon-controller.txt`): how its opener
+//! holds it open, the stick that selects, which buttons the opener may be with that stick, and the
+//! opener each stick had this session. `PadSettings::parse` and `serialize` read and write their
+//! lines (`radialMode`, `radialStick`, `bind_pad.radial`).
+use super::{Button, PadSettings, RADIAL};
+
+/// The buttons under the right thumb, which steers the right stick.
+const RIGHT_THUMB: [Button; 4] = [
+    Button::South,
+    Button::West,
+    Button::North,
+    Button::RightStick,
+];
+/// The buttons under the left thumb, which steers the left stick.
+const LEFT_THUMB: [Button; 5] = [
+    Button::DPadUp,
+    Button::DPadDown,
+    Button::DPadLeft,
+    Button::DPadRight,
+    Button::LeftStick,
+];
+
+/// Whether the radial menu's opener can't be `button` while `stick` selects. One rule: the opener
+/// is never under a thumb that selects (holding it and steering are two jobs for one thumb), nor
+/// B, which cancels the open menu. So with the right stick the face buttons and R3 go, with the
+/// left the D-pad and L3, with either both; a bumper, a trigger and View are always free, and
+/// with a bumper for the opener the other bumper turns the pages.
+pub fn opener_refused(stick: RadialStick, button: Button) -> bool {
+    button == Button::East
+        || (stick != RadialStick::Left && RIGHT_THUMB.contains(&button))
+        || (stick != RadialStick::Right && LEFT_THUMB.contains(&button))
+}
+
+/// How the radial menu's opener holds it open.
+#[derive(Clone, Copy, Debug, PartialEq, Eq, Default)]
+pub enum RadialMode {
+    /// Held: letting go runs what is selected.
+    #[default]
+    Hold,
+    /// A press opens it; A or the opener again runs what is selected, B closes it.
+    Toggle,
+}
+impl RadialMode {
+    pub const ALL: [Self; 2] = [Self::Hold, Self::Toggle];
+    pub fn name(self) -> &'static str {
+        match self {
+            Self::Hold => "hold",
+            Self::Toggle => "toggle",
+        }
+    }
+    pub fn parse(value: &str) -> Self {
+        Self::ALL
+            .into_iter()
+            .find(|mode| mode.name() == value)
+            .unwrap_or_default()
+    }
+}
+
+/// The stick that selects in the radial menu.
+#[derive(Clone, Copy, Debug, PartialEq, Eq, Default)]
+pub enum RadialStick {
+    #[default]
+    Right,
+    Left,
+    /// The last stick to lean past the select tilt.
+    Either,
+}
+impl RadialStick {
+    pub const ALL: [Self; 3] = [Self::Right, Self::Left, Self::Either];
+    pub fn name(self) -> &'static str {
+        match self {
+            Self::Right => "right",
+            Self::Left => "left",
+            Self::Either => "either",
+        }
+    }
+    pub fn parse(value: &str) -> Self {
+        Self::ALL
+            .into_iter()
+            .find(|stick| stick.name() == value)
+            .unwrap_or_default()
+    }
+}
+
+/// The opener each stick had, for this session: what the player stepped through, not a setting,
+/// so it is neither saved nor compared.
+#[derive(Clone, Copy, Debug, Default)]
+pub(super) struct StickOpeners([Option<Button>; 3]);
+impl PartialEq for StickOpeners {
+    fn eq(&self, _: &Self) -> bool {
+        true
+    }
+}
+impl StickOpeners {
+    fn slot(&mut self, stick: RadialStick) -> &mut Option<Button> {
+        let at = RadialStick::ALL
+            .iter()
+            .position(|s| *s == stick)
+            .unwrap_or(0);
+        &mut self.0[at]
+    }
+}
+
+impl PadSettings {
+    /// Whether `button` can be bound to `action`: anything but the radial menu's opener under
+    /// a thumb that selects, or on B (`opener_refused`).
+    pub fn can_bind(&self, action: &str, button: Button) -> bool {
+        action != RADIAL || !opener_refused(self.radial_stick, button)
+    }
+    /// The stick the radial menu selects with. An opener under the thumb that now selects is
+    /// unbound, and its row in the radial page says so. An unbound opener then takes the one this
+    /// stick had before in this session, or else its default where nothing else has it (D-pad
+    /// Right, back on the right stick).
+    pub fn set_radial_stick(&mut self, stick: RadialStick) {
+        let was = self.radial_stick;
+        *self.openers.slot(was) = self.binding(RADIAL);
+        self.radial_stick = stick;
+        if self
+            .binding(RADIAL)
+            .is_some_and(|b| opener_refused(stick, b))
+        {
+            self.bindings.insert(RADIAL, None);
+        }
+        if self.binding(RADIAL).is_some() {
+            return;
+        }
+        // The player's own, shared or not: they put it there.
+        if let Some(own) = self
+            .openers
+            .slot(stick)
+            .filter(|b| !opener_refused(stick, *b))
+        {
+            self.bind(RADIAL, Some(own));
+            return;
+        }
+        let default = Self::default_of(RADIAL);
+        let free =
+            default.is_some_and(|d| !opener_refused(stick, d) && self.actions_of(d).is_empty());
+        if free {
+            self.bindings.remove(RADIAL);
+        }
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use super::super::Rumble;
+    use super::*;
+
+    #[test]
+    fn a_new_player_holds_d_pad_right_for_the_radial_menu() {
+        for s in [PadSettings::default(), PadSettings::parse("")] {
+            assert_eq!(s.binding(RADIAL), Some(Button::DPadRight));
+            assert!(!s.conflicts(RADIAL));
+        }
+        let s = PadSettings::parse(&PadSettings::default().serialize());
+        assert_eq!(s, PadSettings::default());
+    }
+
+    #[test]
+    fn a_button_bound_by_hand_stays_with_it_over_the_openers_default() {
+        let s = PadSettings::parse("bindLayout:1\nbind_key.playerlist:right\n");
+        assert_eq!(s.binding("key.playerlist"), Some(Button::DPadRight));
+        assert_eq!(s.binding(RADIAL), None);
+        assert!(!s.conflicts("key.playerlist"));
+        assert_eq!(PadSettings::parse(&s.serialize()), s);
+    }
+
+    #[test]
+    fn a_saved_opener_stays_where_it_was_saved() {
+        let s =
+            PadSettings::parse("bindLayout:1\nbind_pad.radial:right\nbind_key.playerlist:right\n");
+        assert_eq!(s.binding(RADIAL), Some(Button::DPadRight));
+    }
+
+    #[test]
+    fn a_conflict_made_since_the_migration_stays_after_a_restart() {
+        // Bound in the binds list onto the opener's button: both stay, and the list marks it.
+        let mut s = PadSettings::default();
+        s.bind("key.playerlist", Some(Button::DPadRight));
+        let text = s.serialize();
+        assert!(text.contains("bindLayout:2"));
+        let read = PadSettings::parse(&text);
+        assert_eq!(read.binding(RADIAL), Some(Button::DPadRight));
+        assert!(read.conflicts(RADIAL));
+        assert_eq!(read, s);
+        // The same, hand-written with spaces around the lines.
+        let read = PadSettings::parse("  bindLayout:2\n  bind_key.playerlist:right\n");
+        assert_eq!(read.binding(RADIAL), Some(Button::DPadRight));
+    }
+
+    #[test]
+    fn a_layout_one_file_resolves_the_opener_once() {
+        let s = PadSettings::parse("bind_key.chat:up\n bindLayout:1\nbind_key.playerlist:right\n");
+        assert_eq!(s.binding(RADIAL), None, "the player's own button wins");
+        assert_eq!(s.binding("key.playerlist"), Some(Button::DPadRight));
+        assert_eq!(s.binding("key.chat"), Some(Button::DPadUp));
+        let text = s.serialize();
+        assert!(text.contains("bindLayout:2\n") && text.contains("bind_pad.radial:none\n"));
+        assert_eq!(PadSettings::parse(&text), s);
+        // Without a conflict the opener keeps its default.
+        let s = PadSettings::parse("bindLayout:1\nvibration:false\n");
+        assert_eq!(s.binding(RADIAL), Some(Button::DPadRight));
+        // A line with leading spaces is still a saved opener.
+        let s =
+            PadSettings::parse("bindLayout:1\n bind_pad.radial:right\nbind_key.playerlist:right\n");
+        assert_eq!(s.binding(RADIAL), Some(Button::DPadRight));
+    }
+
+    #[test]
+    fn the_opener_never_goes_under_the_selecting_thumb_nor_on_b() {
+        use Button as B;
+        let face = [B::South, B::West, B::North, B::RightStick];
+        let dpad = [
+            B::DPadUp,
+            B::DPadDown,
+            B::DPadLeft,
+            B::DPadRight,
+            B::LeftStick,
+        ];
+        for stick in RadialStick::ALL {
+            let mut s = PadSettings::default();
+            s.set_radial_stick(stick);
+            for button in Button::ALL {
+                let refused = button == B::East
+                    || (stick != RadialStick::Left && face.contains(&button))
+                    || (stick != RadialStick::Right && dpad.contains(&button));
+                assert_eq!(!s.can_bind(RADIAL, button), refused, "{stick:?} {button:?}");
+                // Other actions still take any of them.
+                assert!(s.can_bind("key.chat", button));
+            }
+            // A bumper is always free, and stays one through the file.
+            s.bind(RADIAL, Some(B::LeftBumper));
+            assert_eq!(s.binding(RADIAL), Some(B::LeftBumper), "{stick:?}");
+            assert_eq!(PadSettings::parse(&s.serialize()), s, "{stick:?}");
+        }
+        // A file with a refused opener reads as never saved: the default, unless taken.
+        for button in [B::South, B::East, B::West, B::North, B::RightStick] {
+            let text = format!("bindLayout:2\nbind_pad.radial:{}\n", button.name());
+            let read = PadSettings::parse(&text);
+            assert_eq!(read.binding(RADIAL), Some(B::DPadRight), "{button:?}");
+            let taken = format!("{text}bind_key.playerlist:right\n");
+            assert_eq!(
+                PadSettings::parse(&taken).binding(RADIAL),
+                None,
+                "{button:?}"
+            );
+        }
+        // Read with the stick it was saved for, wherever the stick's line is.
+        let left = PadSettings::parse("bind_pad.radial:north\nbindLayout:2\nradialStick:left\n");
+        assert_eq!(left.binding(RADIAL), Some(B::North));
+    }
+
+    #[test]
+    fn a_stick_that_takes_the_openers_thumb_unbinds_it_and_the_right_gives_it_back() {
+        let mut s = PadSettings::default();
+        s.set_radial_stick(RadialStick::Left);
+        assert_eq!(
+            s.binding(RADIAL),
+            None,
+            "D-pad Right is under the left thumb"
+        );
+        assert_eq!(PadSettings::parse(&s.serialize()).binding(RADIAL), None);
+        s.set_radial_stick(RadialStick::Right);
+        assert_eq!(s.binding(RADIAL), Some(Button::DPadRight));
+        // An opener the player picked that both sticks allow stays.
+        s.bind(RADIAL, Some(Button::RightBumper));
+        s.set_radial_stick(RadialStick::Either);
+        assert_eq!(s.binding(RADIAL), Some(Button::RightBumper));
+    }
+
+    #[test]
+    fn stepping_the_stick_and_back_gives_each_stick_its_own_opener() {
+        // Left with Y, back to the right stick: Y is under the right thumb, D-pad Right opens.
+        let mut s = PadSettings::default();
+        s.set_radial_stick(RadialStick::Left);
+        s.bind(RADIAL, Some(Button::North));
+        s.set_radial_stick(RadialStick::Right);
+        assert_eq!(s.binding(RADIAL), Some(Button::DPadRight));
+        // And Left again has its Y back, shared with Inventory as the player left it.
+        s.set_radial_stick(RadialStick::Left);
+        assert_eq!(s.binding(RADIAL), Some(Button::North));
+        // Right with D-pad Left: the left stick refuses it, and the right gets it back.
+        let mut s = PadSettings::default();
+        s.bind(RADIAL, Some(Button::DPadLeft));
+        s.set_radial_stick(RadialStick::Left);
+        assert_eq!(s.binding(RADIAL), None);
+        s.set_radial_stick(RadialStick::Either);
+        assert_eq!(s.binding(RADIAL), None);
+        s.set_radial_stick(RadialStick::Right);
+        assert_eq!(s.binding(RADIAL), Some(Button::DPadLeft));
+    }
+
+    #[test]
+    fn a_file_from_before_the_radial_menu_binds_no_opener() {
+        let s = PadSettings::parse("vibration:false\nbind_key.chat:up\n");
+        assert_eq!(s.binding(RADIAL), None);
+        assert_eq!(PadSettings::parse(&s.serialize()), s);
+    }
+
+    #[test]
+    fn the_radial_menus_ticks_are_felt_and_tell_apart() {
+        let tick = Rumble::RadialSlot.pulse().unwrap();
+        assert!((40..=50).contains(&tick.millis), "{tick:?}");
+        assert!((0.25..=0.35).contains(&tick.weak), "{tick:?}");
+        let page = Rumble::RadialPage.pulse().unwrap();
+        assert!(page.millis < tick.millis, "a page turn is the shorter tick");
+        assert_eq!(Rumble::RadialWrap.pulse(), Some(page));
+        let nothing = Rumble::RadialNothing.pulse().unwrap();
+        assert!(
+            nothing.strong > 0.0 && nothing.millis > tick.millis,
+            "{nothing:?}"
+        );
+        assert!(
+            nothing.strong.max(nothing.weak) < 0.3,
+            "a soft buzz: {nothing:?}"
+        );
+    }
+
+    #[test]
+    fn the_radial_menus_mode_and_stick_survive_the_settings_file() {
+        let s = PadSettings::default();
+        assert_eq!(
+            (s.radial_mode, s.radial_stick),
+            (RadialMode::Hold, RadialStick::Right)
+        );
+        for mode in RadialMode::ALL {
+            for stick in RadialStick::ALL {
+                let mut s = PadSettings {
+                    radial_mode: mode,
+                    ..PadSettings::default()
+                };
+                s.set_radial_stick(stick);
+                assert_eq!(PadSettings::parse(&s.serialize()), s);
+            }
+        }
+        let read = PadSettings::parse("radialMode:sideways\nradialStick:up\n");
+        assert_eq!(
+            (read.radial_mode, read.radial_stick),
+            (RadialMode::Hold, RadialStick::Right)
+        );
+    }
+
+    #[test]
+    fn radial_pages_survive_the_settings_file() {
+        let mut s = PadSettings::default();
+        let pages = "radial_0_label:Mine\nradial_0_slots:key.chat,,,,,,,\n";
+        s.radial =
+            crate::radial::Pages::parse(pages.lines().filter_map(|l| l.split_once(':'))).unwrap();
+        let read = PadSettings::parse(&s.serialize());
+        assert_eq!(read.radial, s.radial);
+        assert_ne!(read.radial, crate::radial::Pages::default());
+    }
+}
@@ -141,8 +141,13 @@ impl Guide {
    pub fn at_detail(self, detail: GuideDetail) -> Self {
        match detail {
            GuideDetail::Full => self,
+            // Nothing else in play names the radial menu.
            GuideDetail::Basic => Guide {
-                left: Vec::new(),
+                left: self
+                    .left
+                    .into_iter()
+                    .filter(|row| row.caption == crate::gamepad::RADIAL_CAPTION)
+                    .collect(),
                right: self.right,
            },
            GuideDetail::Off => Guide {
@@ -178,6 +183,8 @@ pub fn resolve(facts: &Facts, settings: &PadSettings) -> Guide {
                "key.swapOffhand",
                (player && any_item).then_some("horizon.controller.guide.swap"),
            ),
+            // Nothing else in play says the menu is there; it opens for a spectator too.
+            row(crate::gamepad::RADIAL, Some(crate::gamepad::RADIAL_CAPTION)),
        ]
        .into_iter()
        .flatten()
@@ -566,6 +573,7 @@ mod tests {
                (Button::North, "key.inventory"),
                (Button::DPadDown, "horizon.controller.guide.drop"),
                (Button::West, "horizon.controller.guide.swap"),
+                (Button::DPadRight, crate::gamepad::RADIAL_CAPTION),
            ]
        );
    }
@@ -736,12 +744,12 @@ mod tests {
                gliding: true,
                ..Facts::default()
            }),
-            ["key.inventory"]
+            ["key.inventory", crate::gamepad::RADIAL_CAPTION]
        );
    }

    #[test]
-    fn a_spectator_only_flies_opens_spectates_and_has_its_menu() {
+    fn a_spectator_only_flies_opens_spectates_and_has_its_menus() {
        let facts = Facts {
            spectator: true,
            flying: true,
@@ -765,7 +773,8 @@ mod tests {
            captions(&guide.left),
            [
                "horizon.controller.guide.fly_up",
-                "horizon.controller.guide.fly_down"
+                "horizon.controller.guide.fly_down",
+                crate::gamepad::RADIAL_CAPTION
            ]
        );
    }
@@ -0,0 +1,15 @@
+//! The engine's side of the input source (docs/layers.md, "Controllers, splitscreen, replays and
+//! UI pages"): what gameplay tells a device beyond the keyboard and mouse. Gameplay names these
+//! types, never a controller's; the controller code answers.
+
+/// Something that happened to the player that a device may let them feel (a controller's
+/// vibration). The device decides how, or whether.
+#[derive(Clone, Copy, Debug, PartialEq)]
+pub enum Feedback {
+    /// The player broke a block.
+    BlockBroken,
+    /// An explosion this far away (blocks) with this power.
+    Explosion { distance: f64, radius: f32 },
+    /// A totem of undying saved the player.
+    Totem,
+}
@@ -9,11 +9,13 @@ pub mod gamepad;
 pub mod gameplay_guide;
 pub mod held;
 pub mod input;
+pub mod input_source;
 pub mod interaction_input;
 pub mod key_names;
 pub mod keybinds;
 pub mod keymapping;
 pub mod modifiers;
 pub mod mouse;
+pub mod radial;
 pub mod snap;
 pub mod window;
@@ -638,10 +638,30 @@ pub fn fullscreen_request(
    }
 }

-/// Horizon's icon for the window's title bar and the task bar (X11 and Windows; Wayland takes
-/// it from the `horizon.desktop` entry, macOS from the app bundle). `None` if it can't be read.
+/// The PNG the windows show as their icon, given once at startup by the layer that brands the
+/// game (the engine has none of its own).
+static ICON_PNG: std::sync::OnceLock<&'static [u8]> = std::sync::OnceLock::new();
+
+/// Give the windows their icon, a PNG: call it before the first window opens. A second call
+/// keeps the first icon.
+pub fn set_icon_png(png: &'static [u8]) {
+    let _ = ICON_PNG.set(png);
+}
+
+/// The icon given to [`set_icon_png`], if any.
+pub fn icon_png() -> Option<&'static [u8]> {
+    ICON_PNG.get().copied()
+}
+
+/// The icon for the window's title bar and the task bar (X11 and Windows; Wayland takes it from
+/// the `.desktop` entry, macOS from the app bundle). `None` with no icon given, or one that
+/// can't be read.
 pub fn icon() -> Option<winit::window::Icon> {
-    let mut decoder = png::Decoder::new(std::io::Cursor::new(horizon_theme::ICON_PNG));
+    decode_icon(icon_png()?)
+}
+
+fn decode_icon(png: &[u8]) -> Option<winit::window::Icon> {
+    let mut decoder = png::Decoder::new(std::io::Cursor::new(png));
    decoder.ignore_checksums(true);
    decoder.set_transformations(png::Transformations::EXPAND | png::Transformations::STRIP_16);
    let mut reader = decoder.read_info().ok()?;
@@ -654,14 +674,15 @@ pub fn icon() -> Option<winit::window::Icon> {
    winit::window::Icon::from_rgba(bytes, info.width, info.height).ok()
 }

-/// Apply Horizon's icon to every window. Windows has a separate taskbar icon slot from the small
-/// window icon; requiring the decoded icon there prevents a generic taskbar icon from appearing.
-pub fn with_horizon_icon(
-    attributes: winit::window::WindowAttributes,
-) -> winit::window::WindowAttributes {
+/// Apply the icon given to [`set_icon_png`] to a window. Windows has a separate taskbar icon slot
+/// from the small window icon; requiring a given icon to decode there prevents a generic taskbar
+/// icon from appearing.
+pub fn with_icon(attributes: winit::window::WindowAttributes) -> winit::window::WindowAttributes {
+    #[cfg(not(target_os = "windows"))]
    let icon = icon();
    #[cfg(target_os = "windows")]
-    let icon = Some(icon.expect("Horizon's icon must be available on Windows"));
+    let icon =
+        icon_png().map(|png| decode_icon(png).expect("the window icon must decode on Windows"));

    let attributes = attributes.with_window_icon(icon.clone());
    #[cfg(target_os = "windows")]
@@ -670,6 +691,39 @@ pub fn with_horizon_icon(
    attributes
 }

+/// The screen a window is on: its size in physical pixels, its refresh rate where the OS gives
+/// it, and its scale. For `horizon-ctl status` and the performance statistics' `system.display`.
+#[derive(Clone, Copy, Debug, PartialEq)]
+pub struct Display {
+    pub width: u32,
+    pub height: u32,
+    pub refresh_hz: Option<u32>,
+    pub scale: f64,
+}
+
+/// The screen `window` is on, else the primary one, else the only one: right after the window
+/// is made, Wayland doesn't say yet which screen it is on.
+pub fn monitor(window: &winit::window::Window) -> Option<winit::monitor::MonitorHandle> {
+    let only = || {
+        let mut all = window.available_monitors();
+        all.next().filter(|_| all.next().is_none())
+    };
+    window
+        .current_monitor()
+        .or_else(|| window.primary_monitor())
+        .or_else(only)
+}
+
+/// [`monitor`]'s size, refresh rate and scale.
+pub fn display(window: &winit::window::Window) -> Option<Display> {
+    monitor(window).map(|m| Display {
+        width: m.size().width,
+        height: m.size().height,
+        refresh_hz: m.refresh_rate_millihertz().map(|r| r.div_ceil(1000)),
+        scale: m.scale_factor(),
+    })
+}
+
 #[cfg(test)]
 mod tests {
    use super::*;
@@ -706,7 +760,8 @@ mod tests {
    }
    #[test]
    fn the_window_icon_decodes() {
-        assert!(icon().is_some());
+        assert!(decode_icon(horizon_theme::ICON_PNG).is_some());
+        assert!(decode_icon(b"not a png").is_none());
    }

    #[test]
@@ -42,8 +42,6 @@ horizon-chat-filter = { path = "../horizon-chat-filter" }
 horizon-shaders = { path = "../horizon-shaders" }
 # Horizon's own shader packs: the format, the stages and the check (docs/shaders.md).
 horizon-shader-api = { path = "../horizon-shader-api" }
-# Play with Friends: invite codes and their tunnel; the `friends` feature.
-horizon-friends = { path = "../horizon-friends", optional = true }
 # The narrator (GameNarrator): text-to-speech of chat, system messages and screens.
 horizon-narrator = { path = "../horizon-narrator" }
 # Horizon mods: sandboxed WebAssembly components, off unless installed and turned on (docs/mods.md).
@@ -72,7 +70,6 @@ flate2 = { version = "1.1.10", default-features = false, features = ["zlib-rs",
 mio = { version = "1.2.4", features = ["os-poll", "net"] }
 # Shared chunk frames are found by one keyed 128-bit hash of their body (lan/conn.rs SharedFrames).
 xxhash-rust = { version = "0.8.19", features = ["xxh3"] }
-horizon-theme = { path = "../horizon-theme" }
 # Opt-in data collection: the game keeps, the launcher sends (docs/telemetry.md).
 horizon-telemetry = { path = "../horizon-telemetry", default-features = false }
 horizon-bench = { path = "../horizon-bench" }
@@ -111,16 +108,12 @@ objc2-foundation = { version = "0.3", default-features = false, features = ["std
 wgpu = { version = "30.0.1", default-features = false, features = ["gles"] }

 [features]
-default = ["audio", "controllers", "discord", "friends"]
+default = ["audio", "controllers"]
 # Sound output. Without it (and `controllers`) the program links neither libasound nor libudev on
 # Linux: the server build (`--no-default-features`, released as horizon-engine; docs/server.md).
 audio = ["horizon-client-render/audio"]
 # Controllers: gilrs, and the DualSense's own output. Without it only `horizon-ctl pad`'s virtual pad.
 controllers = ["dep:gilrs", "horizon-client-input/controllers"]
-# "Playing Horizon" on the player's Discord profile (`discord_presence`).
-discord = []
-# Play with Friends, joining side (`net.rs`): without it no invite code joins.
-friends = ["dep:horizon-friends"]
 # Records the call sites of mob random draws (`mob_ai_probe` traces).
 rng-trace = ["horizon-core/rng-trace"]
 # Compatibility with earlier experiment commands: main already uses mimalloc.
@@ -132,6 +125,8 @@ windows-segment-heap = []
 workspace = true

 [dev-dependencies]
+# ui_theme's unit tests draw text in the design system's fonts.
+horizon-theme = { path = "../horizon-theme" }
 horizon-client-render = { path = "../horizon-client-render", features = ["test-support"] }
 horizon-items = { path = "../horizon-items", features = ["test-support"] }
 # Every WGSL shader translated as wgpu's DirectX 12 backend does (gfx.rs tests).
@@ -26,11 +26,9 @@ horizon-narrator = { path = "../horizon-narrator" }
 horizon-optifine = { path = "../horizon-optifine" }
 horizon-polytone = { path = "../horizon-polytone" }
 horizon-protocol = { path = "../horizon-protocol" }
-horizon-render-pipeline = { path = "../horizon-render-pipeline" }
 horizon-shader-api = { path = "../horizon-shader-api" }
 horizon-shaders = { path = "../horizon-shaders" }
 horizon-system = { path = "../horizon-system" }
-horizon-theme = { path = "../horizon-theme" }
 horizon-threads = { path = "../horizon-threads" }
 horizon-world = { path = "../horizon-world" }
 ab_glyph = "0.2.32"
@@ -77,10 +75,16 @@ wgpu = { version = "30.0.1", default-features = false, features = ["gles"] }
 audio = ["dep:cpal"]
 # Helpers horizon-client's tests build their fixtures with.
 test-support = []
+# horizon-client's `horizon-extras`: asking the device for hardware ray tracing on request
+# (`gfx/ray_query.rs`, `HORIZON_RAY_TRACING=1`). Without it the device is requested as without
+# the variable.
+horizon-extras = []

 [lints]
 workspace = true

 [dev-dependencies]
+# Tests: a TrueType font to load, and the design system the menus' motion curves match.
+horizon-theme = { path = "../horizon-theme" }
 horizon-items = { path = "../horizon-items", features = ["test-support"] }
 naga = { version = "30.0.1", features = ["wgsl-in", "hlsl-out", "glsl-out", "msl-out", "spv-out"] }
@@ -0,0 +1,158 @@
+//! Audio occlusion, attenuation and mixing benchmark.
+//! Run with: `cargo run --profile fast -p horizon-client-render --example audio_bench`
+use horizon_client_render::{
+    audio::Audio,
+    sound_engine::{MobSound, SoundInstance, Sounds, TickContext},
+};
+use std::{path::Path, time::Instant};
+
+fn main() {
+    println!("=== Horizon Audio Attenuation & Mixing Benchmark ===");
+
+    let mut audio = Audio::silent(Path::new("/nonexistent"));
+    audio.engine.loaded = true;
+    audio.backend_live_for_bench();
+    audio.record_heard = false;
+
+    // Register a sound event with attenuation distance 16
+    audio.engine.registry.add_file(
+        "minecraft",
+        br#"{"bench.loop":{"attenuation_distance":16,"sounds":[{"name":"bench/loop","stream":false}]}}"#,
+        &|_, _| true,
+    );
+    // Insert 1 second of audio into cache (48000 mono samples)
+    let samples: Vec<f32> = (0..48_000)
+        .map(|i| ((i as f32) * 440.0 * 2.0 * std::f32::consts::PI / 48000.0).sin() * 0.5)
+        .collect();
+    audio.insert_cached_sound("minecraft:bench/loop", samples, 48_000, 1);
+
+    // 1. Benchmark set_listener (called every client render frame)
+    let listener_iterations = 200_000;
+    let start = Instant::now();
+    for i in 0..listener_iterations {
+        let angle = (i as f32) * 0.01;
+        audio.set_listener(
+            [
+                100.0 + (angle.cos() as f64) * 5.0,
+                64.0,
+                200.0 + (angle.sin() as f64) * 5.0,
+            ],
+            angle,
+            0.0,
+        );
+    }
+    let listener_elapsed = start.elapsed();
+    println!(
+        "1. set_listener moving (render frame): {:?} for {} calls ({:.2} ns/call)",
+        listener_elapsed,
+        listener_iterations,
+        (listener_elapsed.as_nanos() as f64) / (listener_iterations as f64)
+    );
+
+    // 1b. Benchmark set_listener stationary (lock elimination early-out)
+    let stationary_iterations = 200_000;
+    let start = Instant::now();
+    for _ in 0..stationary_iterations {
+        audio.set_listener([100.0, 64.0, 200.0], 0.0, 0.0);
+    }
+    let stationary_elapsed = start.elapsed();
+    println!(
+        "1b. set_listener stationary (lock early-out): {:?} for {} calls ({:.2} ns/call)",
+        stationary_elapsed,
+        stationary_iterations,
+        (stationary_elapsed.as_nanos() as f64) / (stationary_iterations as f64)
+    );
+
+    // 2. Play 128 sounds in the world at various distances from listener at [100.0, 64.0, 200.0]
+    // 64 sounds within attenuation distance (<16 blocks)
+    // 64 sounds outside attenuation distance (>16 blocks)
+    for i in 0..128 {
+        let dist = if i < 64 {
+            (i as f64) * 0.24 // 0 to 15.1 blocks (audible)
+        } else {
+            17.0 + ((i - 64) as f64) * 1.5 // 17 to 111.5 blocks (out of attenuation range)
+        };
+        let pos = [100.0 + dist, 64.0, 200.0];
+        let instance = SoundInstance::new(
+            "minecraft:bench.loop",
+            crate_sound_source(i),
+            1.0,
+            1.0,
+            horizon_core::random::LegacyRandom::new(i as i64),
+            true, // looping
+            0,
+            horizon_client_render::sound_engine::Attenuation::Linear,
+            pos,
+            false,
+        );
+        audio.play_instance(instance, false);
+    }
+
+    // 3. Benchmark mix_buffer (5000 buffers of 1024 stereo frames @ 48kHz = ~106 seconds of audio mixing)
+    let mut buffer = vec![0.0f32; 1024 * 2];
+    let mix_iterations = 5_000;
+    let start = Instant::now();
+    for _ in 0..mix_iterations {
+        audio.mix_buffer(&mut buffer, 2, 48_000);
+    }
+    let mix_elapsed = start.elapsed();
+    println!(
+        "2. mix_buffer (128 active channels, 1024 stereo frames): {:?} for {} buffers ({:.2} µs/buffer)",
+        mix_elapsed,
+        mix_iterations,
+        (mix_elapsed.as_micros() as f64) / (mix_iterations as f64)
+    );
+
+    // 4. Benchmark SoundEngine::tick with ticking mob sounds
+    let mut mobs = Vec::new();
+    for i in 0..64 {
+        mobs.push(MobSound {
+            id: 2000 + i,
+            position: [100.0 + (i as f64) * 0.5, 64.0, 200.0 + (i as f64) * 0.5],
+            speed: 0.25,
+            baby: false,
+            angry: i % 2 == 0,
+            silent: false,
+            attack_scale: 0.5,
+            sniffer_digging: false,
+        });
+    }
+
+    let tick_ctx = TickContext {
+        player_underwater: false,
+        player_removed: false,
+        vehicle: None,
+        carts: Vec::new(),
+        mobs: mobs.clone(),
+        frozen: false,
+        player_position: [100.0, 64.0, 200.0],
+        player_speed_sqr: 0.1,
+        player_fall_flying: false,
+        ridden: None,
+        camera_position: [100.0, 64.0, 200.0],
+    };
+
+    let tick_iterations = 10_000;
+    let start = Instant::now();
+    for _ in 0..tick_iterations {
+        audio.tick(false, &tick_ctx);
+    }
+    let tick_elapsed = start.elapsed();
+    println!(
+        "3. SoundEngine::tick (64 channels + ticking): {:?} for {} ticks ({:.2} µs/tick)",
+        tick_elapsed,
+        tick_iterations,
+        (tick_elapsed.as_micros() as f64) / (tick_iterations as f64)
+    );
+}
+
+fn crate_sound_source(i: u32) -> usize {
+    match i % 6 {
+        0 => 0, // master
+        1 => 1, // music
+        2 => 2, // records
+        3 => 3, // weather
+        4 => 4, // blocks
+        _ => 5, // hostile
+    }
+}
@@ -386,6 +386,7 @@ fn replay(window: Arc<Window>) -> Result<(), Box<dyn std::error::Error>> {
                path: path.clone(),
                size: None,
                scaled: false,
+                background: false,
            });
            for _ in 0..32 {
                draw(&mut renderer)?;
@@ -207,6 +207,7 @@ fn fixture(window: Arc<Window>) -> Result<(), Box<dyn std::error::Error>> {
        path: out.join("cpu.png"),
        size: None,
        scaled: false,
+        background: false,
    });
    renderer.render(&frame)?;
    let expected = read(&out.join("cpu.png"));
@@ -251,6 +252,7 @@ fn fixture(window: Arc<Window>) -> Result<(), Box<dyn std::error::Error>> {
        path: out.join("gpu.png"),
        size: None,
        scaled: false,
+        background: false,
    });
    renderer.render(&frame)?;
    assert_eq!(
@@ -362,7 +364,7 @@ fn fixture_frame(hud: &HudBatch) -> Frame<'_> {
        outline: Vec::new(),
        outline_after_terrain: false,
        outline_high_contrast: false,
-        look: Default::default(),
+        pvp: Default::default(),
        debug_lines: &[],
        debug_lines_on_top: &[],
        debug_crosshair: &[],
@@ -167,6 +167,7 @@ fn fixture(window: Arc<Window>) -> Result<(), Box<dyn std::error::Error>> {
            path: path.clone(),
            size: None,
            scaled: false,
+            background: false,
        });
        // twice: the first frame of a new warp builds it
        renderer.render(&frame).unwrap();
@@ -336,6 +337,7 @@ fn bench(renderer: &mut Renderer, out: &Path) -> Result<(), Box<dyn std::error::
            path: out.join("bench.png"),
            size: None,
            scaled: false,
+            background: false,
        });
        renderer.render(&frame).unwrap();
        renderer.render(&frame).unwrap();
@@ -430,7 +432,7 @@ fn fixture_frame(hud: &HudBatch) -> Frame<'_> {
        outline: Vec::new(),
        outline_after_terrain: false,
        outline_high_contrast: false,
-        look: Default::default(),
+        pvp: Default::default(),
        debug_lines: &[],
        debug_lines_on_top: &[],
        debug_crosshair: &[],
@@ -382,8 +382,8 @@ impl RenderAssets {
        };
        // After the connected tiles: a tile identical to a block shares its layer, and the
        // overlays skip shared layers.
-        if draws {
-            emissive = crate::native_emissive::load_optifine(root, &mut sprites);
+        if draws && let Some(suffix) = crate::pack_hooks::formats().emissive_suffix(root) {
+            emissive = crate::native_emissive::load_overlays(root, &suffix, &mut sprites);
        }
        sprites.save_disk_cache();
        if draws {
@@ -233,11 +233,11 @@ pub fn texture_path(root: &Path, texture: &str, directory: &str) -> PathBuf {
    }
    let (namespace, path) = texture.split_once(':').unwrap_or(("minecraft", texture));
    let rel = format!("assets/{namespace}/{directory}/{path}.png");
-    root.join(if horizon_optifine::paths::valid(&rel) {
-        &rel
-    } else {
-        NOWHERE
-    })
+    // No `.`, `..` or empty segment, and no `\` (a separator on Windows, where `..\..` climbs).
+    let stays = rel
+        .split('/')
+        .all(|segment| !matches!(segment, "" | "." | "..") && !segment.contains('\\'));
+    root.join(if stays { &rel } else { NOWHERE })
 }

 /// `SpriteSourceList.list`: every sprite id of the atlas and its origin.
@@ -478,6 +478,7 @@ pub struct Audio {
    pub record_heard: bool,
    pub listener: [f64; 3],
    pub listener_yaw: f32,
+    pub listener_pitch: f32,
    pub master: f32,
    /// Seeds of positional plays (the client level random's `nextLong`).
    random: LegacyRandom,
@@ -722,6 +723,29 @@ impl Backend for MixerBackend {
    fn set_unmuffled(&mut self, channel: ChannelId, unmuffled: bool) {
        self.with(channel, |c| c.unmuffled = unmuffled);
    }
+    fn update_channel(&mut self, channel: ChannelId, volume: f32, pitch: f32, position: [f64; 3]) {
+        if let Ok(mut m) = self.mixer.lock()
+            && let Some(c) = m.channels.get_mut(&channel)
+        {
+            c.gain = volume;
+            c.pitch = pitch;
+            c.at = [position[0] as f32, position[1] as f32, position[2] as f32];
+        }
+    }
+    fn filter_stopped(&mut self, live: &[(u64, ChannelId)], stopped: &mut Vec<u64>) {
+        if let Ok(m) = self.mixer.lock() {
+            for &(h, c) in live {
+                if m.channels
+                    .get(&c)
+                    .is_none_or(|ch| ch.state == State::Stopped)
+                {
+                    stopped.push(h);
+                }
+            }
+        } else {
+            stopped.extend(live.iter().map(|&(h, _)| h));
+        }
+    }
    /// `getCompleteBuffer` (cached, else decoded on the decoder thread) or
    /// `getStream` (decoded on a thread of its own), then attach and
    /// `alSourcePlay`. A sound that cannot load leaves its source initial,
@@ -822,18 +846,24 @@ impl Backend for MixerBackend {
 /// pinned client's) rendered through `ALC_SOFT_loopback` within 1e-5.
 fn stereo_gains(right: f32, up: f32, forward: f32) -> [f32; 2] {
    let length = (right * right + up * up + forward * forward).sqrt();
+    stereo_gains_with_length(right, up, forward, length)
+}
+#[inline]
+fn stereo_gains_with_length(right: f32, up: f32, forward: f32, length: f32) -> [f32; 2] {
    if length <= f32::EPSILON {
-        return stereo_gains(0.0, 0.0, 1.0);
+        return stereo_gains_with_length(0.0, 0.0, 1.0, 1.0);
    }
-    let elevation = (up / length).clamp(-1.0, 1.0).asin();
+    let u = (up / length).clamp(-1.0, 1.0);
+    let cos_elev = (1.0 - u * u).max(0.0).sqrt();
    let mut azimuth = right.atan2(forward);
    if azimuth.abs() < std::f32::consts::FRAC_PI_2 {
        azimuth = (azimuth.abs() * 1.5)
            .min(std::f32::consts::FRAC_PI_2)
            .copysign(azimuth);
    }
-    let side = azimuth.sin() * elevation.cos();
-    let front = azimuth.cos() * elevation.cos() * 0.095_660_8;
+    let (sin_az, cos_az) = azimuth.sin_cos();
+    let side = sin_az * cos_elev;
+    let front = cos_az * cos_elev * 0.095_660_8;
    [0.5 - 0.5 * side + front, 0.5 + 0.5 * side + front]
 }
 /// The gain OpenAL applies for distance (`AL_LINEAR_DISTANCE` with reference
@@ -853,16 +883,10 @@ fn mix(mixer: &mut Mixer, data: &mut [f32], channels: usize, rate: u32) {
    // and OpenAL's right = forward x up.
    let basis = |yaw: f32, pitch: f32| {
        let (yaw, pitch) = (f64::from(yaw.to_radians()), f64::from(pitch.to_radians()));
-        let forward = [
-            -yaw.sin() * pitch.cos(),
-            -pitch.sin(),
-            yaw.cos() * pitch.cos(),
-        ];
-        let up = [
-            -yaw.sin() * pitch.sin(),
-            pitch.cos(),
-            yaw.cos() * pitch.sin(),
-        ];
+        let (yaw_sin, yaw_cos) = yaw.sin_cos();
+        let (pitch_sin, pitch_cos) = pitch.sin_cos();
+        let forward = [-yaw_sin * pitch_cos, -pitch_sin, yaw_cos * pitch_cos];
+        let up = [-yaw_sin * pitch_sin, pitch_cos, yaw_cos * pitch_sin];
        let right = [
            forward[1] * up[2] - forward[2] * up[1],
            forward[2] * up[0] - forward[0] * up[2],
@@ -896,7 +920,7 @@ fn mix(mixer: &mut Mixer, data: &mut [f32], channels: usize, rate: u32) {
    // Gains and pans per source for this buffer.
    let mut voices = std::mem::take(&mut mixer.voices);
    voices.clear();
-    for (id, c) in &mixer.channels {
+    for (id, c) in &mut mixer.channels {
        let Some((_, source_rate, source_channels)) = &c.samples else {
            continue;
        };
@@ -907,6 +931,7 @@ fn mix(mixer: &mut Mixer, data: &mut [f32], channels: usize, rate: u32) {
        if c.state != State::Playing {
            continue;
        }
+
        let at = [f64::from(c.at[0]), f64::from(c.at[1]), f64::from(c.at[2])];
        let away = |listener: [f64; 3]| {
            [
@@ -915,45 +940,56 @@ fn mix(mixer: &mut Mixer, data: &mut [f32], channels: usize, rate: u32) {
                at[2] - listener[2],
            ]
        };
-        let length = |d: [f64; 3]| d[0] * d[0] + d[1] * d[1] + d[2] * d[2];
-        // The nearest camera hears it (one camera but in splitscreen).
-        let camera = mixer
-            .cameras
-            .iter()
-            .filter(|camera| c.relative || camera.2 == c.world)
-            .min_by(|a, b| length(away(a.0)).total_cmp(&length(away(b.0))))
-            .map(|camera| (camera.0, camera.1));
-        // Unheard sources still advance: returning to a world must not resume stale sounds.
+        let length_sq = |d: [f64; 3]| d[0] * d[0] + d[1] * d[1] + d[2] * d[2];
+        let camera = if !shared {
+            let cam = &mixer.cameras[0];
+            if c.relative || cam.2 == c.world {
+                Some((cam.0, cam.1))
+            } else {
+                None
+            }
+        } else {
+            mixer
+                .cameras
+                .iter()
+                .filter(|camera| c.relative || camera.2 == c.world)
+                .min_by(|a, b| length_sq(away(a.0)).total_cmp(&length_sq(away(b.0))))
+                .map(|camera| (camera.0, camera.1))
+        };
        let (listener, (forward, up, right)) = camera.unwrap_or(([0.0; 3], basis(0.0, 0.0)));
        let d = if c.relative { at } else { away(listener) };
-        let distance = (d[0] * d[0] + d[1] * d[1] + d[2] * d[2]).sqrt() as f32;
-        let gain = if camera.is_some() {
-            c.gain.clamp(0.0, 1.0)
-                * if direct {
-                    1.0
-                } else {
-                    distance_gain(c.linear, distance)
+        let d_sqr = length_sq(d);
+
+        let (gain, [left, right]) = if camera.is_none() {
+            (0.0, [0.0, 0.0])
+        } else if direct {
+            let gain = c.gain.clamp(0.0, 1.0);
+            (gain, [gain, gain])
+        } else {
+            let mut zero = false;
+            if let Some(max) = c.linear {
+                let max_d = max as f64;
+                if max <= 0.0 || (!c.relative && d_sqr >= max_d * max_d) {
+                    zero = true;
                }
-        } else {
-            0.0
-        };
-        let [left, right] = if direct {
-            [gain, gain]
-        } else {
-            // Relative sources are already in OpenAL's listener space (-Z ahead).
-            let [mut left, mut right] = if c.relative {
-                stereo_gains(d[0] as f32, d[1] as f32, -d[2] as f32)
-            } else {
-                stereo_gains(dot(d, right), dot(d, up), dot(d, forward))
-            };
-            if shared {
-                // Several players on the speakers: half the stereo width, as left and right are
-                // nobody's in particular.
-                let middle = (left + right) / 2.0;
-                left = middle + (left - middle) / 2.0;
-                right = middle + (right - middle) / 2.0;
            }
-            [left * gain, right * gain]
+            if zero {
+                (0.0, [0.0, 0.0])
+            } else {
+                let distance = d_sqr.sqrt() as f32;
+                let gain = c.gain.clamp(0.0, 1.0) * distance_gain(c.linear, distance);
+                let [mut left, mut right] = if c.relative {
+                    stereo_gains_with_length(d[0] as f32, d[1] as f32, -d[2] as f32, distance)
+                } else {
+                    stereo_gains_with_length(dot(d, right), dot(d, up), dot(d, forward), distance)
+                };
+                if shared {
+                    let middle = (left + right) * 0.5;
+                    left = middle + (left - middle) * 0.5;
+                    right = middle + (right - middle) * 0.5;
+                }
+                (gain, [left * gain, right * gain])
+            }
        };
        let step = f64::from(*source_rate) / f64::from(rate) * f64::from(c.pitch.max(0.0));
        voices.push((*id, [left, right, gain], step));
@@ -974,6 +1010,40 @@ fn mix(mixer: &mut Mixer, data: &mut [f32], channels: usize, rate: u32) {
        };
        let source_channels = source_channels as usize;
        let frames = samples.len() / source_channels;
+        let inaudible = if channels >= 2 {
+            left == 0.0 && right == 0.0
+        } else {
+            gain == 0.0
+        };
+        if inaudible {
+            let buffer_frames = data.len() / channels;
+            // As the loop below: a sound of one frame or none stops, looping or not.
+            if !c.looping || frames <= 1 {
+                // `frames` may be 0: no `frames - 1` in usize. A step of 0 never
+                // reaches the end, as in the loop below.
+                let needed = frames as f64 - 1.0 - c.position;
+                if needed <= 0.0 {
+                    c.state = State::Stopped;
+                } else if step > 0.0 {
+                    let steps_to_stop = needed / step;
+                    if (buffer_frames as f64) >= steps_to_stop {
+                        c.state = State::Stopped;
+                    } else {
+                        c.position += step * (buffer_frames as f64);
+                    }
+                }
+            } else {
+                for _ in 0..buffer_frames {
+                    let i = c.position as usize;
+                    if i + 1 >= frames {
+                        c.position = 0.0;
+                    }
+                    c.position += step;
+                }
+            }
+            continue;
+        }
+
        let out: &mut [f32] = if muffling && !c.unmuffled {
            &mut bus
        } else {
@@ -992,8 +1062,8 @@ fn mix(mixer: &mut Mixer, data: &mut [f32], channels: usize, rate: u32) {
            }
            let t = (c.position - i as f64) as f32;
            if source_channels > 1 {
-                let l = samples[i * 2] * (1.0 - t) + samples[(i + 1) * 2] * t;
-                let r = samples[i * 2 + 1] * (1.0 - t) + samples[(i + 1) * 2 + 1] * t;
+                let l = samples[i * 2] + (samples[(i + 1) * 2] - samples[i * 2]) * t;
+                let r = samples[i * 2 + 1] + (samples[(i + 1) * 2 + 1] - samples[i * 2 + 1]) * t;
                if channels >= 2 {
                    frame[0] += l * left;
                    frame[1] += r * right;
@@ -1001,7 +1071,7 @@ fn mix(mixer: &mut Mixer, data: &mut [f32], channels: usize, rate: u32) {
                    frame[0] += (l + r) * 0.5 * gain;
                }
            } else {
-                let s = samples[i] * (1.0 - t) + samples[i + 1] * t;
+                let s = samples[i] + (samples[i + 1] - samples[i]) * t;
                if channels >= 2 {
                    frame[0] += s * left;
                    frame[1] += s * right;
@@ -1412,6 +1482,7 @@ impl Audio {
            record_heard: false,
            listener: [0.0; 3],
            listener_yaw: 0.0,
+            listener_pitch: 0.0,
            master: 1.0,
            random: crate::random_source::create(),
            source_override: None,
@@ -1535,8 +1606,12 @@ impl Audio {
    /// `SoundManager.updateSource`: the camera position and rotation
    /// (`Listener.setTransform` takes its forward and up vectors).
    pub fn set_listener(&mut self, position: [f64; 3], yaw: f32, pitch: f32) {
+        if self.listener == position && self.listener_yaw == yaw && self.listener_pitch == pitch {
+            return;
+        }
        self.listener = position;
        self.listener_yaw = yaw;
+        self.listener_pitch = pitch;
        if let Ok(mut m) = self.backend.mixer.lock() {
            if self.backend.owner == 0 {
                m.listener = position;
@@ -1576,6 +1651,7 @@ impl Audio {
            record_heard: false,
            listener: [0.0; 3],
            listener_yaw: 0.0,
+            listener_pitch: 0.0,
            master: self.master,
            random: crate::random_source::create(),
            source_override: None,
@@ -2109,6 +2185,25 @@ impl Audio {
            })
            .collect()
    }
+    /// Mixes one buffer of audio into `data` (channels: 1 or 2, rate in Hz).
+    pub fn mix_buffer(&mut self, data: &mut [f32], channels: usize, rate: u32) {
+        if let Ok(mut m) = self.backend.mixer.lock() {
+            mix(&mut m, data, channels, rate);
+        }
+    }
+    #[doc(hidden)]
+    pub fn insert_cached_sound(&mut self, key: &str, samples: Vec<f32>, rate: u32, channels: u16) {
+        if let Ok(mut c) = self.backend.cache.lock() {
+            c.insert(
+                key.to_owned(),
+                Some((std::sync::Arc::new(samples), rate, channels)),
+            );
+        }
+    }
+    #[doc(hidden)]
+    pub fn backend_live_for_bench(&mut self) {
+        self.backend.live = true;
+    }
 }
 impl Sounds for Audio {
    fn engine(&mut self) -> &mut SoundEngine {
@@ -2613,6 +2708,25 @@ mod tests {
        assert_eq!(data, [0.0; 4], "returning must not resume the old one-shot");
    }

+    /// A sound of one frame or none, heard or not, looping or not, stops at its first
+    /// buffer as the mixing loop stops it: none stays playing (and holds its channel).
+    #[test]
+    fn sounds_too_short_to_mix_stop_even_unheard() {
+        for (samples, looping) in [(vec![], false), (vec![1.0], false), (vec![1.0], true)] {
+            let mut mixer = Mixer::default();
+            let mut source = channel(samples.clone(), None, [0.0; 3], looping);
+            source.gain = 0.0;
+            mixer.channels.insert(1, source);
+            let mut data = [0.0; 4];
+            mix(&mut mixer, &mut data, 2, 48_000);
+            assert_eq!(
+                mixer.channels[&1].state,
+                State::Stopped,
+                "{samples:?} {looping}"
+            );
+        }
+    }
+
    #[test]
    fn variants_of_one_sound_are_the_same_sound() {
        assert_eq!(
@@ -121,8 +121,8 @@ impl CommandBlock {
            condition_met: flag("conditionMet", false),
        }
    }
-    /// `CommandBlockEntity.saveAdditional`. The last output is written as a
-    /// plain string component.
+    /// `CommandBlockEntity.saveAdditional`. The last output is the component
+    /// itself (`ComponentSerialization.CODEC`), styles and click events kept.
    pub fn save(&self) -> Vec<(&'static str, Tag)> {
        let mut out = vec![
            ("Command", Tag::String(self.command.as_str().into())),
@@ -135,7 +135,7 @@ impl CommandBlock {
        if self.track_output
            && let Some(last) = &self.last_output
        {
-            out.push(("LastOutput", Tag::String(last.plain().as_str().into())));
+            out.push(("LastOutput", scoreboard::component_tag(&last.component())));
        }
        out.push((
            "UpdateLastExecution",
@@ -57,6 +57,8 @@ pub enum Item {
    /// Wait for a button to bind to this action.
    Bind(&'static str),
    ResetBinds,
+    /// Opens the radial menu's pages (`radial_editor`).
+    Radial,
    Info(Info),
 }

@@ -106,6 +108,15 @@ fn choice_description(opt: Opt, pad: &PadSettings) -> Option<&'static str> {
            }
            gamepad::Lightbar::Off => "A DualSense keeps its own light.",
        },
+        Opt::PadRadialMode => match pad.radial_mode {
+            gamepad::RadialMode::Hold => "horizon.options.radial_mode.hold.about",
+            gamepad::RadialMode::Toggle => "horizon.options.radial_mode.toggle.about",
+        },
+        Opt::PadRadialStick => match pad.radial_stick {
+            gamepad::RadialStick::Right => "horizon.options.radial_stick.right.about",
+            gamepad::RadialStick::Left => "horizon.options.radial_stick.left.about",
+            gamepad::RadialStick::Either => "horizon.options.radial_stick.either.about",
+        },
        _ => return None,
    })
 }
@@ -123,6 +134,11 @@ fn info(info: Info, text: &'static str) -> Setting {
    }
 }

+/// The radial menu's group, on General (how it opens and selects) and Bindings (its pages).
+const RADIAL_GROUP: &str = "Radial Menu";
+/// The row that opens the radial menu's pages.
+const RADIAL_PAGES: &str = "horizon.pages.open.controller_radial";
+
 /// Shown on a binding's row until it is focused, and in the search.
 const BIND_TEXT: &str = "Press this row, then the button that should do it.";

@@ -201,6 +217,13 @@ pub fn rows() -> Vec<(Page, Vec<(&'static str, Vec<Setting>)>)> {
                        ),
                    ],
                ),
+                (
+                    RADIAL_GROUP,
+                    vec![
+                        option(Opt::PadRadialMode, "horizon.options.radial_mode.about"),
+                        option(Opt::PadRadialStick, "horizon.options.radial_stick.about"),
+                    ],
+                ),
                (
                    "Menus",
                    vec![
@@ -231,6 +254,13 @@ pub fn rows() -> Vec<(Page, Vec<(&'static str, Vec<Setting>)>)> {
        (
            Page::Bindings,
            vec![
+                (
+                    RADIAL_GROUP,
+                    vec![Setting {
+                        item: Item::Radial,
+                        text: "Named pages of eight actions, held open with a button.",
+                    }],
+                ),
                ("Actions", binds),
                (
                    "Reset",
@@ -437,6 +467,7 @@ fn row(setting: Setting, s: &Settings, context: &Context) -> Row<Item> {
            Row::new(item, name, value).about(about)
        }
        Item::ResetBinds => Row::new(item, lang::get(RESET_ALL), Value::Press).about(about),
+        Item::Radial => Row::new(item, lang::get(RADIAL_PAGES), Value::Press).about(about),
        Item::Info(which) => {
            let (name, value) = context.read(which);
            Row::new(item, lang::get(name), Value::Read(value)).about(about)
@@ -496,6 +527,7 @@ impl Screen for ControllerScreen {
                s.controller.reset_bindings();
                vec![Output::Event(Event::Changed)]
            }
+            Item::Radial => vec![Output::Push(crate::options_ui::Page::ControllerRadial)],
            Item::Bind(_) | Item::Info(_) => Vec::new(),
        }
    }
@@ -533,15 +565,21 @@ impl Screen for ControllerScreen {
    fn undoes(&self) -> bool {
        true
    }
-    /// This player's controller settings, bindings included, as the screen found them.
+    /// This player's controller settings, bindings included, as the screen found them. The
+    /// radial menu's pages stay as they are: their own screen has its own Undo.
    fn undo(&mut self, s: &mut Settings, before: &Settings) -> Vec<Output> {
+        let radial = std::mem::take(&mut s.controller.radial);
        s.controller = before.controller.clone();
+        s.controller.radial = radial;
        Vec::new()
    }
    /// Undo is there exactly while the controller settings differ from what the screen opened
-    /// with: a binding the game made while the row waited counts, a value stepped back doesn't.
+    /// with: a binding the game made while the row waited counts, a value stepped back doesn't,
+    /// and nor do the radial menu's pages, which this Undo keeps.
    fn differs(&self, s: &Settings, before: &Settings) -> Option<bool> {
-        Some(s.controller != before.controller)
+        let mut now = s.controller.clone();
+        now.radial = before.controller.radial.clone();
+        Some(now != before.controller)
    }
 }

@@ -793,6 +831,48 @@ mod tests {
        assert_eq!(arts(&batch, row), 0);
    }

+    /// The radial menu's pages have their own screen and Undo: editing them shows no Undo here,
+    /// and another change's Undo keeps them as edited.
+    #[test]
+    fn radial_pages_edited_on_their_own_screen_leave_undo_alone() {
+        let mut s = Settings::default();
+        let mut ui = ui(Page::General);
+        draw(&mut ui, &s, None);
+        s.controller.radial.remove(1);
+        draw(&mut ui, &s, None);
+        assert!(
+            !ui.changed(),
+            "Undo here keeps the pages: it has nothing to do"
+        );
+        s.controller.invert_y = !s.controller.invert_y;
+        draw(&mut ui, &s, None);
+        assert!(ui.changed());
+        let reached = (0..100).any(|_| {
+            key(&mut ui, &mut s, K::Tab);
+            ui.focused() == Some(Target::Undo)
+        });
+        assert!(reached);
+        key(&mut ui, &mut s, K::Enter);
+        assert_eq!(s.controller.radial.len(), 1);
+        assert_eq!(s.controller.invert_y, PadSettings::default().invert_y);
+    }
+
+    /// The Bindings page's radial row opens the radial menu's pages.
+    #[test]
+    fn the_radial_row_opens_the_radial_pages() {
+        let mut s = Settings::default();
+        let mut ui = ui(Page::Bindings);
+        let at = ui.point_at(&s, SIZE, Item::Radial);
+        let outputs = ui.click(&mut s, at, SIZE, false, false, false);
+        assert_eq!(
+            outputs,
+            [
+                CLICK,
+                Output::Push(crate::options_ui::Page::ControllerRadial)
+            ]
+        );
+    }
+
    #[test]
    fn the_search_finds_rows_across_pages_and_drops_empty_pages() {
        let s = Settings::default();
@@ -816,8 +896,8 @@ mod tests {
        let mut s = Settings::default();
        s.controller.bind(JUMP, Some(Button::North));
        let mut ui = ui(Page::Bindings);
-        // Search, the three pages, then the first action.
-        for _ in 0..Page::ALL.len() + 2 {
+        // Search, the three pages, the radial menu's row, then the first action.
+        for _ in 0..Page::ALL.len() + 3 {
            key(&mut ui, &mut s, K::Tab);
        }
        assert_eq!(ui.focused(), Some(Target::Row(Item::Bind(JUMP))));
@@ -939,6 +1019,8 @@ mod tests {
            (Opt::PadNintendoButtons, 2),
            (Opt::PadKeyboard, 3),
            (Opt::PadLightbar, 3),
+            (Opt::PadRadialMode, 2),
+            (Opt::PadRadialStick, 3),
        ] {
            let setting = option(opt, "the fixed sentence");
            let mut seen = Vec::new();
@@ -972,6 +1054,8 @@ mod tests {
                Opt::PadNintendoButtons,
                Opt::PadKeyboard,
                Opt::PadLightbar,
+                Opt::PadRadialMode,
+                Opt::PadRadialStick,
            ] {
                for _ in 0..4 {
                    lang::get(choice_description(opt, &settings.controller).unwrap());
@@ -990,6 +1074,7 @@ mod tests {
            }
            ControllerScreen::default().side();
            lang::get(TITLE);
+            lang::get(RADIAL_PAGES);
            for text in [
                "Press the button for this. %s cancels.",
                "This button also does: %s",
@@ -1,27 +1,34 @@
-//! OptiFine custom skies (`horizon_optifine::sky`) as the game draws them: a pack's layers with
-//! their decoded textures, read once with the pack, and each frame's choice of layers, their
-//! brightness and rotation ([`CustomSky::draws`]), which `gfx::custom_sky` draws over the
-//! vanilla sky. A pack without `optifine/sky` gives an empty [`CustomSky`] and the sky stays
-//! vanilla.
+//! Custom sky layers: skyboxes a pack draws over the vanilla sky, in a format vanilla doesn't read
+//! (OptiFine's), which the platform's pack formats fill ([`crate::pack_hooks`]). The layers'
+//! textures are read once with the pack; each frame the game asks for the layers to draw, their
+//! brightness and rotation ([`SkyLayers::draws`]), and `gfx::custom_sky` draws them over the
+//! vanilla sky. A pack without layers keeps the vanilla sky.

 use std::path::Path;
+use std::sync::Arc;

-use glam::{Mat4, Vec3};
-use horizon_optifine::sky::{Blend, Conditions, Skies, SkyLayer, Transition};
+use glam::Mat4;

-/// A layer's texture, RGBA8.
+/// A layer's texture, RGBA8: the skybox's six faces in a 3x2 grid, bottom, top and south in the
+/// top row, west, north and east below (`gfx::custom_sky`'s faces).
 pub struct Image {
    pub width: u32,
    pub height: u32,
    pub rgba: Vec<u8>,
 }

-/// The pack's layers, by world, with one texture per layer (`images[i]` for the `i`th layer
-/// over all worlds, in `worlds` order).
-#[derive(Default)]
-pub struct CustomSky {
-    worlds: Vec<(i32, Vec<SkyLayer>)>,
-    pub images: Vec<Image>,
+/// How a layer mixes with what is drawn below it.
+#[derive(Clone, Copy, Debug, PartialEq, Eq)]
+pub enum Blend {
+    Add,
+    Subtract,
+    Multiply,
+    Dodge,
+    Burn,
+    Screen,
+    Replace,
+    Overlay,
+    Alpha,
 }

 /// One layer of a frame: which texture, with which blend, how bright and turned how.
@@ -34,62 +41,44 @@ pub struct Draw {
    pub rotation: Mat4,
 }

+/// The weather of a frame: thunder is a storm's rain, so it is only `Thunder`.
+#[derive(Clone, Copy, Debug, PartialEq, Eq)]
+pub enum Weather {
+    Clear,
+    Rain,
+    Thunder,
+}
+
+/// What a frame's layers may depend on.
+#[derive(Clone, Copy, Debug)]
+pub struct Conditions<'a> {
+    /// Ticks of the day, counting the days.
+    pub day_time: i64,
+    pub weather: Weather,
+    /// The biome at the camera, namespaced.
+    pub biome: &'a str,
+    /// The camera's block height.
+    pub y: i32,
+}
+
 /// The eased brightness of each layer, kept by the game between frames.
 #[derive(Default)]
 pub struct State {
-    world: Option<i32>,
-    eased: Vec<Transition>,
+    /// The world the layers were last drawn for.
+    pub world: Option<i32>,
+    /// Each layer's eased visibility, 0 to 1.
+    pub eased: Vec<f32>,
 }

-/// Textures past this many texels in all are left out (a skybox is a few megapixels at most).
-const TEXEL_BUDGET: u64 = 64 << 20;
-
-impl CustomSky {
-    /// The custom skies of the overlay at `root`. A layer whose texture does not decode is
-    /// dropped with a warning.
-    pub fn load(root: &Path) -> Self {
-        let skies = Skies::scan(root);
-        let mut out = Self::default();
-        let mut texels = 0u64;
-        for (world, sky) in skies.worlds {
-            let mut layers = Vec::new();
-            for layer in sky.layers {
-                match crate::hud::decode(&root.join(&layer.source)) {
-                    Ok((width, height, rgba))
-                        if texels + u64::from(width) * u64::from(height) <= TEXEL_BUDGET =>
-                    {
-                        texels += u64::from(width) * u64::from(height);
-                        out.images.push(Image {
-                            width,
-                            height,
-                            rgba,
-                        });
-                        layers.push(layer);
-                    }
-                    Ok(_) => log::warn!("{}: past the custom sky's texture budget", layer.source),
-                    Err(e) => log::warn!("{}: {e:#}", layer.source),
-                }
-            }
-            if !layers.is_empty() {
-                out.worlds.push((world, layers));
-            }
-        }
-        out
-    }
-
-    pub fn is_empty(&self) -> bool {
-        self.worlds.is_empty()
-    }
-
-    /// Whether `world` has layers (`0` the Overworld, `1` the End).
-    pub fn has(&self, world: i32) -> bool {
-        self.worlds.iter().any(|(w, _)| *w == world)
-    }
-
-    /// This frame's layers of `world` into `out` (cleared first), in drawing order: those whose
-    /// conditions hold, eased over their `transition` by `seconds` since the last frame, at the
-    /// brightness of their fade times. `sun_turns` is the sun's angle over 360° (`0` at noon).
-    pub fn draws(
+/// A pack's custom sky layers, by world (`0` the Overworld, `1` the End).
+pub trait SkyLayers: Send + Sync {
+    /// Every layer's texture: [`Draw::image`] indexes it.
+    fn images(&self) -> &[Image];
+    /// Whether `world` has layers.
+    fn has(&self, world: i32) -> bool;
+    /// This frame's layers of `world` into `out` (cleared first), in drawing order, eased by
+    /// `seconds` since the last frame. `sun_turns` is the sun's angle over 360° (`0` at noon).
+    fn draws(
        &self,
        world: i32,
        conditions: &Conditions,
@@ -97,147 +86,30 @@ impl CustomSky {
        seconds: f32,
        state: &mut State,
        out: &mut Vec<Draw>,
-    ) {
+    );
+}
+
+/// No layers: the vanilla sky.
+struct NoLayers;
+
+impl SkyLayers for NoLayers {
+    fn images(&self) -> &[Image] {
+        &[]
+    }
+
+    fn has(&self, _: i32) -> bool {
+        false
+    }
+
+    fn draws(&self, _: i32, _: &Conditions, _: f32, _: f32, s: &mut State, out: &mut Vec<Draw>) {
        out.clear();
-        let mut first = 0;
-        let mut found = None;
-        for (w, layers) in &self.worlds {
-            if *w == world {
-                found = Some(layers);
-                break;
-            }
-            first += layers.len();
-        }
-        let Some(layers) = found else {
-            state.world = None;
-            return;
-        };
-        // A new world (or pack) starts each layer where its conditions put it: no fade in.
-        let snap = state.world != Some(world) || state.eased.len() != layers.len();
-        if snap {
-            state.world = Some(world);
-            state.eased.clear();
-            state.eased.resize(layers.len(), Transition::default());
-        }
-        for (i, (layer, eased)) in layers.iter().zip(&mut state.eased).enumerate() {
-            let target = if layer.shows(conditions) { 1.0 } else { 0.0 };
-            let shown = if snap {
-                eased.value = target;
-                target
-            } else {
-                eased.step(target, seconds, layer.transition)
-            };
-            let brightness = shown * layer.brightness(conditions.day_time);
-            if brightness <= 0.0 {
-                continue;
-            }
-            let turns = layer.turns(conditions.day_time, sun_turns);
-            let rotation = if turns == 0.0 {
-                Mat4::IDENTITY
-            } else {
-                Mat4::from_axis_angle(Vec3::from_array(layer.axis), turns * std::f32::consts::TAU)
-            };
-            out.push(Draw {
-                image: (first + i) as u16,
-                blend: layer.blend,
-                brightness,
-                rotation,
-            });
-        }
+        s.world = None;
    }
 }

-#[cfg(test)]
-mod tests {
-    use super::*;
-    use horizon_optifine::sky::Now;
-
-    fn pack(files: &[(&str, &str)]) -> (std::path::PathBuf, CustomSky) {
-        let root = std::env::temp_dir().join(format!(
-            "horizon-custom-sky-{}-{}",
-            std::process::id(),
-            files.len()
-        ));
-        let _ = std::fs::remove_dir_all(&root);
-        let dir = root.join("assets/minecraft/optifine/sky/world0");
-        std::fs::create_dir_all(&dir).unwrap();
-        let png = {
-            let mut bytes = Vec::new();
-            let mut encoder = png::Encoder::new(&mut bytes, 6, 4);
-            encoder.set_color(png::ColorType::Rgba);
-            encoder.set_depth(png::BitDepth::Eight);
-            let mut writer = encoder.write_header().unwrap();
-            writer
-                .write_image_data(&[255, 0, 0, 255].repeat(24))
-                .unwrap();
-            writer.finish().unwrap();
-            bytes
-        };
-        for (name, text) in files {
-            std::fs::write(dir.join(format!("{name}.properties")), text).unwrap();
-            std::fs::write(dir.join(format!("{name}.png")), &png).unwrap();
-        }
-        let sky = CustomSky::load(&root);
-        (root, sky)
-    }
-
-    fn noon(biome: &str) -> Conditions<'_> {
-        Conditions {
-            day_time: 6000,
-            weather: Now::Clear,
-            biome,
-            y: 64,
-        }
-    }
-
-    #[test]
-    fn layers_ease_in_at_a_biome_border_but_not_on_arrival() {
-        let (root, sky) = pack(&[
-            ("sky1", "biomes=desert\ntransition=2"),
-            ("sky2", "blend=alpha\nrotate=false"),
-        ]);
-        let _ = std::fs::remove_dir_all(root);
-        assert!(sky.has(0) && !sky.has(1));
-        assert_eq!(sky.images[0].width, 6);
-        let (mut state, mut out) = (State::default(), Vec::new());
-        sky.draws(
-            0,
-            &noon("minecraft:desert"),
-            0.0,
-            0.05,
-            &mut state,
-            &mut out,
-        );
-        assert_eq!(
-            out.iter().map(|d| d.brightness).collect::<Vec<_>>(),
-            [1.0, 1.0]
-        );
-        // Out of the desert: the first layer fades over its two seconds.
-        sky.draws(0, &noon("minecraft:plains"), 0.0, 0.5, &mut state, &mut out);
-        assert_eq!(out[0].brightness, 0.75);
-        assert_eq!(out[1].blend, Blend::Alpha);
-        sky.draws(0, &noon("minecraft:plains"), 0.0, 2.0, &mut state, &mut out);
-        assert_eq!(out.len(), 1, "a dark layer is not drawn");
-        assert_eq!(out[0].image, 1);
-        // Into the End, which has no layers, and back: no fade.
-        sky.draws(1, &noon("minecraft:desert"), 0.0, 0.0, &mut state, &mut out);
-        assert!(out.is_empty());
-        sky.draws(0, &noon("minecraft:desert"), 0.0, 0.0, &mut state, &mut out);
-        assert_eq!(out.len(), 2);
-    }
-
-    #[test]
-    fn a_layer_turns_west_like_the_sun() {
-        let (root, sky) = pack(&[("sky1", "")]);
-        let _ = std::fs::remove_dir_all(root);
-        let (mut state, mut out) = (State::default(), Vec::new());
-        // A quarter turn after noon (sunset): the skybox's zenith has gone down to the west.
-        let c = Conditions {
-            day_time: 12000,
-            ..noon("minecraft:plains")
-        };
-        sky.draws(0, &c, 0.25, 0.0, &mut state, &mut out);
-        let up = out[0].rotation.transform_vector3(Vec3::Y);
-        assert!((up - Vec3::NEG_X).length() < 1e-5, "{up}");
-    }
+/// The custom sky layers of the overlay at `root`, from the installed pack formats.
+pub fn load(root: &Path) -> Arc<dyn SkyLayers> {
+    crate::pack_hooks::formats()
+        .custom_sky(root)
+        .unwrap_or_else(|| Arc::new(NoLayers))
 }
@@ -569,6 +569,25 @@ pub(crate) fn polytone_noise() -> &'static horizon_core::noise::SimplexNoise {
 }

 impl horizon_polytone::expr::Host for BlockHost<'_> {
+    fn field(
+        &mut self,
+        root: horizon_polytone::expr::Root,
+        field: horizon_polytone::expr::Field,
+    ) -> Option<horizon_polytone::expr::Value> {
+        use horizon_polytone::expr::Field as F;
+        if root != horizon_polytone::expr::Root::Object {
+            return None;
+        }
+        Some(horizon_polytone::expr::Value::Num(match field {
+            F::X => f64::from(self.at[0]),
+            F::Y => f64::from(self.at[1]),
+            F::Z => f64::from(self.at[2]),
+            F::Temperature => f64::from(self.biome.temperature),
+            F::Downfall => f64::from(self.biome.downfall),
+            _ => return None,
+        }))
+    }
+
    fn root(&mut self, root: horizon_polytone::expr::Root) -> horizon_polytone::expr::Value {
        use horizon_polytone::expr::Root;
        horizon_polytone::expr::Value::Object(match root {
@@ -2,7 +2,7 @@
 //! settings, kept in `horizon-extras.txt` next to `options.txt` so that file
 //! stays exactly vanilla's, and the logic behind them. Every extra is off by
 //! default; see `docs/extras.md`. Horizon's own switches outside the Extras page
-//! (No AI, Agent Control, Discord Rich Presence) are kept here too.
+//! (No AI, Agent Control) are kept here too.
 use std::{collections::VecDeque, fs, path::Path};

 pub const FILE: &str = "horizon-extras.txt";
@@ -145,8 +145,6 @@ pub struct Extras {
    /// F3+R and F3+E start/stop a repro recording and write its bundle (off by
    /// default: a recording copies the world).
    pub repro_keys: bool,
-    /// "Playing Horizon" on the player's Discord profile (`discord_presence`; on by default).
-    pub discord_presence: bool,
    /// Another controller can join P1's world (`splitscreen`, off by default).
    pub splitscreen: bool,
    /// Two players in one window: 0 auto (side by side when wider than tall), 1 side by side,
@@ -233,7 +231,6 @@ impl Default for Extras {
            no_ai: false,
            agent_control: false,
            repro_keys: false,
-            discord_presence: true,
            splitscreen: false,
            splitscreen_two: 0,
            splitscreen_three: 0,
@@ -338,7 +335,6 @@ impl Extras {
                horizon_core::no_ai::KEY => e.no_ai = flag(e.no_ai),
                "agentControl" => e.agent_control = flag(e.agent_control),
                "reproKeys" => e.repro_keys = flag(e.repro_keys),
-                "discordPresence" => e.discord_presence = flag(e.discord_presence),
                "splitscreen" => e.splitscreen = flag(e.splitscreen),
                "splitscreenTwo" => e.splitscreen_two = value.parse().unwrap_or(0).min(2),
                "splitscreenThree" => e.splitscreen_three = value.parse().unwrap_or(0).min(2),
@@ -376,7 +372,7 @@ impl Extras {
    }
    pub fn serialize(&self) -> String {
        let mut text = format!(
-            "packBrowser:{}\npregen:{}\nfullbright:{}\ndynamicLights:{}\nzoom:{}\nzoomKey:{}\nzoomLevel:{}\nzoomSmooth:{}\nzoomSensitivity:{}\nlodZoomDetail:{}\nfps:{}\nfpsCorner:{}\nfpsLows:{}\nkeystrokes:{}\nkeystrokesCorner:{}\nkeystrokesCps:{}\nmovedToMods:{}\nminimap:{}\nminimapCorner:{}\nminimapSize:{}\nminimapShape:{}\nminimapZoom:{}\nminimapRotate:{}\nautoReconnect:{}\nuiSoundReserve:{}\nownNameTag:{}\nhideBlockParticles:{}\nmouseTweaks:{}\nmouseTweaksWheel:{}\nsort:{}\nsortKey:{}\nchatAnimation:{}\nchatIndicator:{}\n{}:{}\nagentControl:{}\nreproKeys:{}\ndiscordPresence:{}\nsplitscreen:{}\nsplitscreenTwo:{}\nsplitscreenThree:{}\nsplitscreenNames:{}\nwheelCyclesListSettings:{}\nmusicOff:{}\nmusicPage:{}\ncosmeticsMine:{}\n{}cosmeticsHideFx:{}\ncosmeticsSolo:{}\n{}:{}\n{}:{}\n{}:{}\n",
+            "packBrowser:{}\npregen:{}\nfullbright:{}\ndynamicLights:{}\nzoom:{}\nzoomKey:{}\nzoomLevel:{}\nzoomSmooth:{}\nzoomSensitivity:{}\nlodZoomDetail:{}\nfps:{}\nfpsCorner:{}\nfpsLows:{}\nkeystrokes:{}\nkeystrokesCorner:{}\nkeystrokesCps:{}\nmovedToMods:{}\nminimap:{}\nminimapCorner:{}\nminimapSize:{}\nminimapShape:{}\nminimapZoom:{}\nminimapRotate:{}\nautoReconnect:{}\nuiSoundReserve:{}\nownNameTag:{}\nhideBlockParticles:{}\nmouseTweaks:{}\nmouseTweaksWheel:{}\nsort:{}\nsortKey:{}\nchatAnimation:{}\nchatIndicator:{}\n{}:{}\nagentControl:{}\nreproKeys:{}\nsplitscreen:{}\nsplitscreenTwo:{}\nsplitscreenThree:{}\nsplitscreenNames:{}\nwheelCyclesListSettings:{}\nmusicOff:{}\nmusicPage:{}\ncosmeticsMine:{}\n{}cosmeticsHideFx:{}\ncosmeticsSolo:{}\n{}:{}\n{}:{}\n{}:{}\n",
            bool_text(self.pack_browser),
            bool_text(self.pregen),
            bool_text(self.fullbright),
@@ -418,7 +414,6 @@ impl Extras {
            bool_text(self.no_ai),
            bool_text(self.agent_control),
            bool_text(self.repro_keys),
-            bool_text(self.discord_presence),
            bool_text(self.splitscreen),
            self.splitscreen_two,
            self.splitscreen_three,
@@ -613,8 +608,6 @@ pub enum Item {
    /// Not on the Extras page: Horizon Settings shows No AI, its AI Agent page Agent Control.
    NoAi,
    AgentControl,
-    /// On the Horizon Settings page.
-    DiscordPresence,
    /// On the AI Agent page, next to Agent Control: the F3 recording shortcuts.
    ReproKeys,
    /// On the Splitscreen settings page.
@@ -691,7 +684,6 @@ impl Item {
            Item::NoAi => "horizon.extras.no_ai",
            Item::AgentControl => "horizon.extras.agent_control",
            Item::ReproKeys => "horizon.extras.repro_keys",
-            Item::DiscordPresence => "horizon.extras.discord_presence",
            Item::Splitscreen => "horizon.extras.splitscreen",
            Item::ChatAnimation => "horizon.extras.chat_animation",
            Item::ChatIndicator => "horizon.extras.chat_indicator",
@@ -724,7 +716,6 @@ impl Item {
            Item::NoAi => "horizon.extras.no_ai.tooltip",
            Item::AgentControl => "horizon.extras.agent_control.tooltip",
            Item::ReproKeys => "horizon.extras.repro_keys.tooltip",
-            Item::DiscordPresence => "horizon.extras.discord_presence.tooltip",
            Item::Splitscreen => "horizon.extras.splitscreen.tooltip",
            Item::ChatAnimation => "horizon.extras.chat_animation.tooltip",
            Item::ChatIndicator => "horizon.extras.chat_indicator.tooltip",
@@ -768,7 +759,6 @@ impl Item {
            Item::NoAi => "No AI",
            Item::AgentControl => "Agent Control",
            Item::ReproKeys => "Recording shortcuts",
-            Item::DiscordPresence => "Discord Rich Presence",
            Item::Splitscreen => "Splitscreen",
            Item::WheelCyclesSettings => "Scroll wheel changes settings",
            Item::PackBrowser => "Resource pack browser",
@@ -792,10 +782,9 @@ impl Item {
            ChatIndicator => ChatAnimation,
            Pvp(o) => return o.parent().map(Pvp),
            Fullbright | DynamicLights | OwnNameTag | HideBlockParticles | MouseTweaks | Sort
-            | AutoReconnect | NoAi | AgentControl | ReproKeys | DiscordPresence | Splitscreen
-            | ChatAnimation | WheelCyclesSettings | MusicPage | PackBrowser | CosmeticsMine
-            | CosmeticsOthers | CosmeticsHideFx | CosmeticsSolo | HorizonMarks | HorizonMe
-            | Pregen => {
+            | AutoReconnect | NoAi | AgentControl | ReproKeys | Splitscreen | ChatAnimation
+            | WheelCyclesSettings | MusicPage | PackBrowser | CosmeticsMine | CosmeticsOthers
+            | CosmeticsHideFx | CosmeticsSolo | HorizonMarks | HorizonMe | Pregen => {
                return None;
            }
        })
@@ -844,9 +833,6 @@ impl Item {
            Item::NoAi => {
                "Hides and turns off every AI feature: agent control, horizon-ctl and the MCP servers. The launcher's switch too."
            }
-            Item::DiscordPresence => {
-                "Shows Playing Horizon on your Discord profile while Discord runs: menus, single player or multiplayer, the dimension and the time played. Never a world's name or a server's address."
-            }
            Item::Splitscreen => {
                "In a world, another controller can join as a new player: press A when it asks, then pick a profile and where to play."
            }
@@ -927,7 +913,6 @@ impl Item {
            Item::NoAi => e.no_ai,
            Item::AgentControl => e.agent_control,
            Item::ReproKeys => e.repro_keys,
-            Item::DiscordPresence => e.discord_presence,
            Item::Splitscreen => e.splitscreen,
            Item::WheelCyclesSettings => e.wheel_cycles_settings,
            Item::PackBrowser => e.pack_browser,
@@ -986,7 +971,6 @@ impl Item {
            Item::NoAi => e.no_ai = !e.no_ai,
            Item::AgentControl => e.agent_control = !e.agent_control,
            Item::ReproKeys => e.repro_keys = !e.repro_keys,
-            Item::DiscordPresence => e.discord_presence = !e.discord_presence,
            Item::Splitscreen => e.splitscreen = !e.splitscreen,
            Item::WheelCyclesSettings => e.wheel_cycles_settings = !e.wheel_cycles_settings,
            Item::PackBrowser => e.pack_browser = !e.pack_browser,
@@ -1104,7 +1088,7 @@ mod tests {
        assert!(!d.mouse_tweaks && !d.sort && !d.own_name_tag && !d.ui_sound_reserve);
        assert!(!d.hide_block_particles && !d.pregen);
        assert!(!d.music_page && d.music_off.is_empty());
-        assert!(d.discord_presence && !d.wheel_cycles_settings);
+        assert!(!d.wheel_cycles_settings);
        assert_eq!(Extras::parse(""), d);
        assert_eq!(Extras::parse(&d.serialize()), d);
        let mut e = d.clone();
@@ -1143,7 +1127,6 @@ mod tests {
        e.sort_key = "key.keyboard.r".into();
        e.chat_animation = true;
        e.chat_indicator = false;
-        e.discord_presence = false;
        assert!(!e.splitscreen);
        Item::Splitscreen.cycle(&mut e, false);
        assert_eq!(Item::Splitscreen.switch(&e), Some(true));
@@ -1,5 +1,6 @@
 //! The Horizon Extras page, on the settings shell (`settings_shell`): which rows it has and what
-//! pressing them does. Each one's value and what it does stay in `extras::Item`.
+//! pressing them does. Each one's value and what it does stay in `extras::Item`; the sections crates
+//! add (`horizon_hooks::pages::Place::Extras`) keep theirs.
 use crate::{
    extras::{self, Item},
    lang,
@@ -7,6 +8,7 @@ use crate::{
    settings::Settings,
    settings_shell::{self as shell, Binding, Group, Output, Row, Screen, Sheet, Value},
 };
+use horizon_hooks::pages::{self as added, Act, Label};

 const TITLE: &str = "horizon.pages.extras";
 const ABOUT: &str = "horizon.pages.extras.tooltip";
@@ -31,6 +33,125 @@ pub(crate) enum ExtraRow {
    /// It isn't installed: where to get it. A note, not a button: Options > Mods already has the
    /// one way into the Mods page (`every_setting_and_page_is_reached_from_one_place`).
    ZoomInstall,
+    /// Row `.1` of the section registered page `.0` adds (`Place::Extras`).
+    Added(usize, usize),
+}
+
+#[cfg(test)]
+thread_local! {
+    /// A test's own pages, instead of the game's registered ones: each test runs on its thread.
+    static TEST_PAGES: std::cell::Cell<Option<&'static [&'static dyn added::Page]>> =
+        const { std::cell::Cell::new(None) };
+}
+
+/// The pages crates registered, all places.
+fn pages() -> &'static [&'static dyn added::Page] {
+    #[cfg(test)]
+    if let Some(pages) = TEST_PAGES.get() {
+        return pages;
+    }
+    added::engine::all()
+}
+
+/// The sections of this page, by their index among the registered pages.
+fn sections() -> impl Iterator<Item = (usize, &'static dyn added::Page)> {
+    let pages = pages().iter().copied().enumerate();
+    pages.filter(|(_, page)| page.place() == added::Place::Extras)
+}
+
+fn label_text(label: Label) -> String {
+    match label {
+        Label::Key(key) => lang::get(key),
+        Label::Value(text) => text,
+    }
+}
+
+/// The page's group named `name`, made at the end if it has none.
+fn group_named<'a>(
+    groups: &'a mut Vec<Group<ExtraRow>>,
+    name: &'static str,
+) -> &'a mut Group<ExtraRow> {
+    let at = groups.iter().position(|group| group.name == name);
+    let at = at.unwrap_or_else(|| {
+        groups.push(Group {
+            name,
+            rows: Vec::new(),
+        });
+        groups.len() - 1
+    });
+    &mut groups[at]
+}
+
+/// The sections' rows, in the groups their titles and headings name.
+fn add_sections(groups: &mut Vec<Group<ExtraRow>>) {
+    for (page, section) in sections() {
+        let mut rows = Vec::new();
+        section.rows(&mut rows);
+        let mut name = section.title();
+        for (r, row) in rows.into_iter().enumerate() {
+            let id = ExtraRow::Added(page, r);
+            let row = match row {
+                added::Row::Heading(key) => {
+                    name = key;
+                    continue;
+                }
+                added::Row::Note(text) => Row::new(id, text, Value::Note).live(false),
+                added::Row::Toggle { label, on } => {
+                    Row::new(id, lang::get(label), Value::Switch(on))
+                }
+                added::Row::Cycle { label, value } => {
+                    Row::new(id, lang::get(label), Value::Choice(label_text(value)))
+                }
+                added::Row::Slider { label, value, text } => {
+                    let position = value.clamp(0.0, 1.0);
+                    let text = label_text(text);
+                    let value = Value::Slider {
+                        position,
+                        steps: None,
+                        text,
+                    };
+                    Row::new(id, lang::get(label), value)
+                }
+                added::Row::Button {
+                    label,
+                    active: true,
+                    ..
+                } => Row::new(id, lang::get(label), Value::Press),
+                added::Row::Key { label, key } => {
+                    let key = crate::keybinds::display_name(&key).plain();
+                    Row::new(id, lang::get(label), Value::Read(key))
+                }
+                // A row kind newer than this engine.
+                _ => continue,
+            };
+            let row = match section.tooltip(r) {
+                Some(about) => row.about(label_text(about)),
+                None => row,
+            };
+            group_named(groups, name).rows.push(row);
+        }
+    }
+}
+
+/// Row `r` of registered page `page` was acted on: the options screen saves when it closes.
+fn act(page: usize, r: usize, act: Act) -> Vec<Output> {
+    let Some(section) = pages().get(page) else {
+        return Vec::new();
+    };
+    section.act(r, act);
+    vec![Output::Event(Event::Changed)]
+}
+
+/// Whether row `r` of registered page `page` steps (a switch or a cycle).
+fn steps(page: usize, r: usize) -> bool {
+    let mut rows = Vec::new();
+    if let Some(section) = pages().get(page) {
+        section.rows(&mut rows);
+    }
+    matches!(
+        rows.get(r),
+        Some(added::Row::Toggle { .. } | added::Row::Cycle { .. })
+    )
 }

 fn item_row(item: Item, s: &Settings) -> Row<ExtraRow> {
@@ -85,9 +206,14 @@ impl Screen for ExtrasScreen {
    fn note_lines(&self) -> usize {
        NOTE_LINES
    }
-    /// The rows read the extras, the mods and whether cosmetics are offered.
+    /// The rows read the extras, the mods, whether cosmetics are offered and the sections' rows.
    fn stamp(&self, s: &Settings) -> u64 {
-        shell::stamp_of(&(&s.extras, &s.mods, horizon_cosmetics::enabled()))
+        let mut added = Vec::new();
+        for (_, section) in sections() {
+            section.rows(&mut added);
+        }
+        let cosmetics = horizon_cosmetics::enabled();
+        shell::stamp_of(&(&s.extras, &s.mods, cosmetics, added))
    }
    fn sheets(&self, s: &Settings) -> Vec<Sheet<(), ExtraRow>> {
        let mut groups = vec![Group {
@@ -107,6 +233,7 @@ impl Screen for ExtrasScreen {
                }
            }
        }
+        add_sections(&mut groups);
        vec![Sheet::new((), lang::get(TITLE), lang::get(ABOUT), groups)]
    }
    fn press(&mut self, s: &mut Settings, row: ExtraRow, back: bool) -> Vec<Output> {
@@ -125,16 +252,29 @@ impl Screen for ExtrasScreen {
                Output::Event(Event::NativeSettings(i)),
            ],
            ExtraRow::ZoomInstall => Vec::new(),
+            ExtraRow::Added(page, r) => {
+                act(page, r, if back { Act::PressBack } else { Act::Press })
+            }
+        }
+    }
+    fn slide(&mut self, _s: &mut Settings, row: ExtraRow, position: f32) {
+        if let ExtraRow::Added(page, r) = row {
+            act(page, r, Act::Slide(position));
        }
    }
    /// With the wheel extra on, the wheel over an item changes it, without a click; the mod's rows
    /// let the list scroll.
    fn wheel_step(&mut self, s: &mut Settings, row: ExtraRow, back: bool) -> Option<Vec<Output>> {
-        let ExtraRow::Item(item) = row else {
-            return None;
-        };
-        item.cycle(&mut s.extras, back);
-        Some(vec![Output::Event(Event::Changed)])
+        match row {
+            ExtraRow::Item(item) => {
+                item.cycle(&mut s.extras, back);
+                Some(vec![Output::Event(Event::Changed)])
+            }
+            ExtraRow::Added(page, r) if steps(page, r) => {
+                Some(act(page, r, if back { Act::PressBack } else { Act::Press }))
+            }
+            _ => None,
+        }
    }
 }

@@ -292,4 +432,146 @@ mod tests {
        shell.key(&mut s, K::ArrowDown, None, false, size);
        assert_eq!(shell.focused_row(), Some(first));
    }
+
+    /// A section with a switch in the page's Multiplayer group, then a heading of its own with a
+    /// number that steps either way, a note and a volume.
+    struct Section {
+        on: std::sync::Mutex<bool>,
+        step: std::sync::Mutex<i32>,
+        volume: std::sync::Mutex<f32>,
+    }
+    impl added::Page for Section {
+        fn id(&self) -> &'static str {
+            "test.section"
+        }
+        fn title(&self) -> &'static str {
+            "horizon.extras.header.multiplayer"
+        }
+        fn place(&self) -> added::Place {
+            added::Place::Extras
+        }
+        fn rows(&self, rows: &mut Vec<added::Row>) {
+            rows.push(added::Row::Toggle {
+                label: "test.section.switch",
+                on: *self.on.lock().unwrap(),
+            });
+            rows.push(added::Row::Heading("test.section.heading"));
+            rows.push(added::Row::Cycle {
+                label: "test.section.step",
+                value: Label::Value(self.step.lock().unwrap().to_string()),
+            });
+            rows.push(added::Row::Note("a note".into()));
+            rows.push(added::Row::Slider {
+                label: "test.section.volume",
+                value: *self.volume.lock().unwrap(),
+                text: Label::Value(String::new()),
+            });
+        }
+        fn act(&self, row: usize, act: Act) {
+            match (row, act) {
+                (0, Act::Press | Act::PressBack) => {
+                    let mut on = self.on.lock().unwrap();
+                    *on = !*on;
+                }
+                (2, Act::Press) => *self.step.lock().unwrap() += 1,
+                (2, Act::PressBack) => *self.step.lock().unwrap() -= 1,
+                (4, Act::Slide(v)) => *self.volume.lock().unwrap() = v,
+                _ => {}
+            }
+        }
+    }
+
+    /// A page for Horizon Settings: never on Extras.
+    struct Elsewhere;
+    impl added::Page for Elsewhere {
+        fn id(&self) -> &'static str {
+            "test.elsewhere"
+        }
+        fn title(&self) -> &'static str {
+            "test.elsewhere"
+        }
+        fn place(&self) -> added::Place {
+            added::Place::HorizonSettings
+        }
+        fn rows(&self, rows: &mut Vec<added::Row>) {
+            rows.push(added::Row::button("test.elsewhere.button"));
+        }
+        fn act(&self, _: usize, _: Act) {}
+    }
+
+    fn with_section() -> &'static Section {
+        let section: &'static Section = Box::leak(Box::new(Section {
+            on: false.into(),
+            step: 0.into(),
+            volume: 0.5.into(),
+        }));
+        let pages: &'static [&'static dyn added::Page] = Box::leak(Box::new([
+            &Elsewhere as &dyn added::Page,
+            section as &dyn added::Page,
+        ]));
+        TEST_PAGES.set(Some(pages));
+        section
+    }
+
+    /// The section's first row joins the page's own Multiplayer group, after its rows; its heading
+    /// starts a group after the page's; a page for elsewhere adds nothing.
+    #[test]
+    fn a_section_joins_the_group_its_title_names_and_heads_its_own() {
+        with_section();
+        let s = Settings::default();
+        let sheets = ExtrasScreen.sheets(&s);
+        let groups = &sheets[0].groups;
+        let ids = |name: &str| -> Vec<ExtraRow> {
+            let group = groups.iter().find(|g| g.name == name).unwrap();
+            group.rows.iter().map(|r| r.id).collect()
+        };
+        let multiplayer = ids("horizon.extras.header.multiplayer");
+        assert_eq!(multiplayer.last(), Some(&ExtraRow::Added(1, 0)));
+        assert_eq!(groups.last().unwrap().name, "test.section.heading");
+        let own = [
+            ExtraRow::Added(1, 2),
+            ExtraRow::Added(1, 3),
+            ExtraRow::Added(1, 4),
+        ];
+        assert_eq!(ids("test.section.heading"), own);
+        let all = rows_of(&s);
+        assert!(!all.iter().any(|r| matches!(r.id, ExtraRow::Added(0, _))));
+    }
+
+    /// A click flips the switch, a Shift click steps the number back, the wheel steps it, and the
+    /// note takes no click; the rows show what the section holds after each.
+    #[test]
+    fn a_sections_rows_act_on_it() {
+        let section = with_section();
+        let mut s = Settings::default();
+        let mut shell = Shell::<ExtrasScreen>::default();
+        let switch = ExtraRow::Added(1, 0);
+        let at = shell.point_at(&s, SIZE, switch);
+        assert!(
+            !shell
+                .click(&mut s, at, SIZE, false, false, false)
+                .is_empty()
+        );
+        assert!(*section.on.lock().unwrap());
+        let value = |s: &Settings, id| rows_of(s).into_iter().find(|r| r.id == id).unwrap().value;
+        assert_eq!(value(&s, switch), Value::Switch(true));
+        let step = ExtraRow::Added(1, 2);
+        let mut screen = ExtrasScreen;
+        screen.press(&mut s, step, true);
+        assert_eq!(value(&s, step), Value::Choice("-1".into()));
+        assert!(screen.wheel_step(&mut s, step, false).is_some());
+        assert_eq!(*section.step.lock().unwrap(), 0);
+        assert_eq!(
+            screen.wheel_step(&mut s, ExtraRow::Added(1, 3), false),
+            None
+        );
+        let note = shell.point_at(&s, SIZE, ExtraRow::Added(1, 3));
+        assert!(
+            shell
+                .click(&mut s, note, SIZE, false, false, false)
+                .is_empty()
+        );
+        screen.slide(&mut s, ExtraRow::Added(1, 4), 0.25);
+        assert_eq!(*section.volume.lock().unwrap(), 0.25);
+    }
 }
@@ -231,8 +231,10 @@ pub struct FogInputs<'a> {
    /// `GameRenderer.nightVisionScale` while Night Vision is on without
    /// Darkness, else 0 (`FogRenderer.computeFogColor`'s brightenFactor).
    pub night_vision: f32,
-    /// The packs' Polytone `environment` fog settings.
-    pub environment: horizon_polytone::colors::Environment,
+    /// The packs' `environment` fog settings (Polytone's).
+    pub environment: crate::pack_palette::Environment,
+    /// The packs' fluid modifiers' fog.
+    pub fluid_fog: crate::pack_palette::FluidFogs,
 }

 /// `FogRenderer.setupFog` + `computeFogColor`.
@@ -397,6 +399,24 @@ pub fn setup_fog(tables: &FogTables, state: &FogState, input: &FogInputs) -> Fog
            }
        }
    }
+    // A pack's fluid modifier over its fluid's fog, after everything else (wiki "Custom Colors").
+    let fluid = match input.fog_type {
+        FogType::Lava => input.fluid_fog.lava,
+        FogType::Water if input.blindness.is_none() && input.darkness.is_none() => {
+            input.fluid_fog.water
+        }
+        _ => None,
+    };
+    if let Some(f) = fluid {
+        if let Some(rgb) = f.color {
+            let [r, g, b] = self::rgb(rgb);
+            fog.color = [r, g, b, 1.0];
+        }
+        let end = fog.environmental_end * f.radius;
+        let start = end - (end - fog.environmental_start * f.radius) * f.fade;
+        (fog.environmental_start, fog.environmental_end) = (start, end);
+        (fog.sky_end, fog.cloud_end) = (end, end);
+    }
    let span = (rd / 10.0).clamp(4.0, 64.0);
    fog.render_distance_start = rd - span;
    fog.render_distance_end = rd;
@@ -495,6 +515,7 @@ mod tests {
            full_water_vision: false,
            night_vision: 0.0,
            environment: Default::default(),
+            fluid_fog: Default::default(),
        }
    }
    #[test]
@@ -581,7 +602,7 @@ mod tests {
        let tables = FogTables {
            water_fog_end: vec![1.0],
        };
-        let environment = horizon_polytone::colors::Environment {
+        let environment = crate::pack_palette::Environment {
            powder_snow_fog: Some(0xFF0000),
            blindness_fog_distance: 40.0,
            water_fog_brightening: 0.0,
@@ -611,9 +632,41 @@ mod tests {
        let kept = setup_fog(&tables, &state, &input).color;
        assert_eq!(&kept[..3], &[0.1, 0.2, 0.4]);
    }
+    #[test]
+    fn a_fluid_modifier_scales_and_colours_its_fog_last() {
+        let sky = Sky {
+            fog_start: 10.0,
+            fog_end: 96.0,
+            ..Sky::default()
+        };
+        let tables = FogTables {
+            water_fog_end: vec![1.0],
+        };
+        let mut input = inputs(&sky);
+        input.fog_type = FogType::Lava;
+        input.fire_resistance = true;
+        let vanilla = setup_fog(&tables, &FogState::default(), &input);
+        assert_eq!(
+            (vanilla.environmental_start, vanilla.environmental_end),
+            (0.0, 5.0)
+        );
+        input.fluid_fog.lava = Some(crate::pack_palette::FluidFog {
+            color: Some(0x00FF00),
+            radius: 2.0,
+            fade: 0.5,
+        });
+        let fog = setup_fog(&tables, &FogState::default(), &input);
+        assert_eq!(fog.color, [0.0, 1.0, 0.0, 1.0]);
+        // The end doubles; half the fade from 0 to 10 starts it at 5.
+        assert_eq!(
+            (fog.environmental_start, fog.environmental_end),
+            (5.0, 10.0)
+        );
+        assert_eq!((fog.sky_end, fog.cloud_end), (10.0, 10.0));
+    }
    fn inputs_with<'a>(
        input: &FogInputs<'a>,
-        environment: horizon_polytone::colors::Environment,
+        environment: crate::pack_palette::Environment,
    ) -> FogInputs<'a> {
        FogInputs {
            environment,
@@ -74,6 +74,7 @@ pub use entity_batch::{
    WATER_MASK_OVERLAY, WORLD_TEXT_OVERLAY, WORLD_TEXT_POLYGON_OFFSET_OVERLAY, is_native_terrain,
    mark_oit,
 };
+use external::{ShadowCull, shadow_box, shadow_casters, shadow_runs};
 pub use view::{View, ViewSet};

 /// Window.getAppropriateLineWidth, in framebuffer pixels.
@@ -189,6 +190,7 @@ mod cull;
 mod dx12_compiler;
 mod end_sky;
 pub mod entity_skin;
+pub mod external;
 mod flat;
 mod frame_gen;
 mod gpu_culling;
@@ -201,6 +203,7 @@ pub use hdr::{Calibration as HdrCalibration, Output as HdrOutput};
 mod hold;
 pub use hold::WorldHold;
 pub use output::{DisplayReading, EffectiveOutput, FrameConfiguration, FrameRequest};
+pub use screenshot_save::Saved as SavedScreenshot;
 pub mod block_light;
 mod custom_sky;
 mod displace;
@@ -236,9 +239,11 @@ pub mod panorama;
 mod readback;
 mod resident;
 mod reuse;
+mod screenshot_save;
 mod stars;
 mod surface_setup;
 use surface_setup::{AdapterChoice, AdapterFailure, open_adapter, pick_adapter, set_up_surface};
+mod off_page;
 pub mod submit;
 mod sunrise_fan;
 mod timing;
@@ -250,6 +255,7 @@ mod wgsl_prefix;
 mod world_post;
 pub mod world_primitives;
 mod world_warp;
+use off_page::move_off_page;

 /// A section's instance: its camera-relative origin and, in `w`, the step of
 /// its fixed-point UVs (`terrain.wgsl`'s `terrain_uv`).
@@ -726,62 +732,6 @@ impl Part {
        }
    }
 }
-/// `Renderer::compact_arena`'s and `shrink_translucent`'s moves: what the meshes
-/// hold on `page` of `arena` (`part`) goes to its other pages in video memory,
-/// until the next range would pass `budget` bytes (it keeps what is left; the
-/// first range moves whatever its size, so none keeps the page closed), the
-/// copies into `encoder`, the ranges' flat draw ids (`flat`) and, in the
-/// section arena, GPU culling's records (`records`) along. False when the other
-/// pages have no room left.
-fn move_off_page<'a>(
-    arena: &mut arena::Arena,
-    encoder: &mut wgpu::CommandEncoder,
-    mut flat: Option<(&mut flat::Flat, &wgpu::Device, &mut upload::Uploads)>,
-    mut records: Option<&mut gpu_culling::Records>,
-    meshes: impl Iterator<Item = &'a mut SectionGpu>,
-    page: u32,
-    part: Part,
-    budget: &mut u64,
-) -> bool {
-    debug_assert!(
-        records.is_none() || matches!(part, Part::Section { .. }),
-        "records follow the section arena's ranges"
-    );
-    let mut moved = false;
-    for s in meshes {
-        // Nothing of a mesh here: split, one without solid quads (its (0, 0) is no
-        // range of page 0); in the other arenas, one without translucent quads.
-        let Some((_, start, vertices)) = part.of(s).filter(|r| r.0 == page) else {
-            continue;
-        };
-        let bytes = vertices * arena.stride();
-        if moved && bytes > *budget {
-            break;
-        }
-        let Some(to) = arena.alloc_moved(vertices) else {
-            return false;
-        };
-        arena.copy(encoder, (page, start), to, vertices);
-        arena.release(page, start, vertices);
-        if let (Some((flat, device, uploads)), Some(id)) = (&mut flat, s.flat_id) {
-            let key = match part {
-                Part::Translucent => to.0 + flat::TRANSLUCENT_KEYS,
-                _ => to.0,
-            };
-            flat.place(device, encoder, uploads, id, key, to.1, vertices);
-        }
-        part.set(s, to);
-        // Its solid quads start the range in either layout.
-        if let (Part::Section { .. }, Some(records), Some(id)) =
-            (part, records.as_deref_mut(), s.gpu_id)
-        {
-            records.relocate(id, to.0, u64::from(s.solid_base()));
-        }
-        *budget = budget.saturating_sub(bytes);
-        moved = true;
-    }
-    true
-}
 /// Starts moving a page of a large arena far larger than its ranges in use
 /// (`Arena::oversized`) into a new page of the size they get (`Arena::open_page`),
 /// for `Renderer::shrink_translucent`: the page closes and `move_off_page` empties
@@ -1001,8 +951,8 @@ pub struct Frame<'a> {
    pub outline_after_terrain: bool,
    /// `BlockOutlineRenderState.highContrast`: a thick black outline under a bright one.
    pub outline_high_contrast: bool,
-    /// The outline, hurt overlay and glint colours a crate above set (`horizon_hooks::look`).
-    pub look: horizon_hooks::look::Frame,
+    /// The PvP & HUD page's outline and hit colour (`pvp::Frame`; default: vanilla's).
+    pub pvp: crate::pvp::Frame,
    /// `lines` with a colour and pixel width (`gizmos::camera_relative`):
    /// the fishing line and debug gizmos, depth tested, then gizmos drawn
    /// over everything.
@@ -1138,6 +1088,9 @@ pub struct ScreenshotRequest {
    /// F2's: drawn at the game's resolution (Resolution Scale above 100%) times
    /// `Renderer::screenshot_quality`, not the window's.
    pub scaled: bool,
+    /// Written on a thread of its own (F2's, the world icon's): its outcome comes back a
+    /// frame or a few later in `Renderer::saved_screenshots`, not `screenshot_result`.
+    pub background: bool,
 }
 /// A solid terrain pipeline without HDR output's lighting (terrain.wgsl's `HDR_LIGHTING`),
 /// for the frames HDR is off, and with it where the display offers HDR output: the
@@ -1329,7 +1282,7 @@ pub struct Renderer {
    celestial_buffer: wgpu::Buffer,
    end_sky: end_sky::EndSky,
    stars: stars::Stars,
-    /// OptiFine custom sky layers (`crate::custom_sky`), and the frame's from the game.
+    /// Custom sky layers (`crate::custom_sky`), and the frame's from the game.
    custom_sky: custom_sky::CustomSky,
    custom_sky_draws: Vec<crate::custom_sky::Draw>,
    /// The glowing entities' outline (`LevelRenderer.entityOutlineTarget`).
@@ -1467,8 +1420,10 @@ pub struct Renderer {
    /// Per-frame scratch, kept to avoid allocating every frame.
    visible: Vec<resident::Visible>,
    visible_lods: Vec<lod::Visible>,
-    /// The sections a shader pack's shadow camera sees (`pack_post::ShadowView`).
+    /// The sections a shader pack's shadow camera sees (`external::ShadowView`).
    shadow_visible: Vec<resident::Visible>,
+    /// The external shader pipeline world frames call (`external`); `None` draws vanilla's way.
+    external: Option<Box<dyn external::ExternalPipeline>>,
    translucent_draws: Vec<(u64, usize, [u32; 5], (u32, Option<u32>))>,
    origins: Vec<[f32; 4]>,
    /// `DrawIndexedIndirectArgs` words: index count, instance count, first
@@ -1632,6 +1587,9 @@ pub struct Renderer {
    pub screenshot_result: Option<std::result::Result<[u32; 2], String>>,
    /// The HDR copy the last screenshot wrote beside it, if it wrote one.
    pub screenshot_hdr: Option<std::path::PathBuf>,
+    /// `background` screenshots written since the caller last took them.
+    pub saved_screenshots: Vec<SavedScreenshot>,
+    screenshot_saves: screenshot_save::Saves,
    /// Screenshot Quality (Horizon setting): a `scaled` screenshot's frame is this many
    /// times the game's resolution (1, 2, 4 or 8).
    pub screenshot_quality: u32,
@@ -5131,6 +5089,7 @@ impl Renderer {
            ));
        }
        let world_primitives = world_primitives::WorldPrimitives::new(&device, frame_format);
+        let screenshot_saves = screenshot_save::Saves::new(&device);
        Ok(Self {
            display: None,
            reading: display,
@@ -5335,6 +5294,7 @@ impl Renderer {
            solid_runs: page_runs::PageRuns::default(),
            phase2_runs: page_runs::PageRuns::default(),
            shadow_runs: page_runs::PageRuns::default(),
+            external: None,
            block_entities: Default::default(),
            block_entity_section_revisions: Default::default(),
            block_entity_membership_revisions: Default::default(),
@@ -5402,6 +5362,8 @@ impl Renderer {
            screenshot: None,
            screenshot_result: None,
            screenshot_hdr: None,
+            saved_screenshots: Vec::new(),
+            screenshot_saves,
            screenshot_quality: 1,
            screenshot_halvings: 0,
            gamma: 0.5,
@@ -5517,11 +5479,11 @@ impl Renderer {
            ))
        });
    }
-    /// The pack's OptiFine custom sky layer textures (`crate::custom_sky::CustomSky::load`).
-    pub fn set_custom_sky(&mut self, pack: &crate::custom_sky::CustomSky) {
+    /// The pack's custom sky layer textures (`crate::custom_sky::load`).
+    pub fn set_custom_sky(&mut self, pack: &dyn crate::custom_sky::SkyLayers) {
        self.custom_sky.set_pack(&self.device, &self.queue, pack);
    }
-    /// The custom sky layers the next frame draws (`CustomSky::draws`): the game refills it each
+    /// The custom sky layers the next frame draws (`SkyLayers::draws`): the game refills it each
    /// frame, empty when the world's sky has none.
    pub fn custom_sky_draws(&mut self) -> &mut Vec<crate::custom_sky::Draw> {
        &mut self.custom_sky_draws
@@ -5716,6 +5678,9 @@ impl Renderer {
            self.offscreen = Some(Self::offscreen_target(&self.device, &self.config));
        }
        self.depth = Self::depth(&self.device, &self.config);
+        if let Some(pipeline) = &mut self.external {
+            pipeline.resize([width, height]);
+        }
    }
    /// Whether sections are drawn as one index list per frame (`flat`).
    pub fn flat_draws(&self) -> bool {
@@ -7095,8 +7060,10 @@ impl Renderer {
        }
    }
    /// This renderer's output as applied, with what its destination offers and reports.
-    pub fn output(&self) -> &output::EffectiveOutput {
-        &self.output
+    pub fn output(&self) -> output::EffectiveOutput {
+        let native = self.native.as_ref().map(|n| n.frame.api);
+        self.output
+            .with_pack(self.shader_pack_kind() == Some("iris"), native)
    }
    /// What this renderer's display last reported: a renderer made again for the window
    /// starts from it (`Renderer::new`'s `display`).
@@ -7330,12 +7297,19 @@ impl Renderer {
        }
        Ok(report)
    }
+    /// Sets the external shader pipeline world frames call (`external`), or none.
+    pub fn set_external_pipeline(&mut self, pipeline: Option<Box<dyn external::ExternalPipeline>>) {
+        self.external = pipeline;
+    }
    /// Makes the running shader pack, of either kind, forget what it kept from earlier frames:
    /// the next frame draws as a freshly loaded pack's first. Nothing to do without a pack.
    pub fn reset_shader_pack_history(&mut self) {
        // A frame still on the submit thread uses the targets and readbacks replaced
        // here.
        self.land_frame();
+        if let Some(pipeline) = &mut self.external {
+            pipeline.reset_history();
+        }
        if let Some((_, Some(post))) = &mut self.pack_post {
            post.reset_history(&self.device);
        }
@@ -8029,6 +8003,8 @@ impl Renderer {
        if self.device_lost() {
            return Err("the graphics device was lost".into());
        }
+        let saved = self.screenshot_saves.finished();
+        self.saved_screenshots.extend(saved);
        if let Some(request) = self.capture.take() {
            let result = self.write_capture(&request, frame);
            self.capture_result = Some(result.map_err(|e| e.to_string()));
@@ -8373,9 +8349,7 @@ impl Renderer {
        let taa = !frame.title
            && self.pack_post.as_ref().is_none_or(|p| p.1.is_none())
            && self.native.as_ref().is_none_or(|n| n.post.is_none());
-        let hdr_lighting = self.native.is_none()
-            && self.pack_post.as_ref().is_none_or(|p| p.1.is_none())
-            && std::env::var_os("HORIZON_HDR_LIGHTING").is_none_or(|v| v != "0");
+        let hdr_lighting = self.shader_pack_kind().is_none();
        if let Some(hdr) = &mut self.hdr {
            hdr.lighting = hdr_lighting && hdr.look;
        }
@@ -8506,9 +8480,9 @@ impl Renderer {
            colored_count: [
                frame.colored_lights.len().min(crate::dynamic_light::MAX) as u32,
                // PvP & HUD's hit colour: entity.wgsl's hurt texel, 0 for vanilla's.
-                frame.look.hurt_texel,
+                frame.pvp.hurt_texel,
                // PvP & HUD's glint colour: entity.wgsl's `tinted_glint`, 0 for vanilla's.
-                frame.look.glint,
+                frame.pvp.glint,
                0,
            ],
            emissive_layers: {
@@ -8670,6 +8644,13 @@ impl Renderer {
        // A shader pack's shadow pass draws the sections in its camera's box, all of them (the
        // occlusion graph follows the eye, not the light), within shadowDistanceRenderMul; for
        // an Iris-format pack, only those whose shadow can fall into the camera's view.
+        let state = external::FrameState {
+            frame,
+            output: &output,
+        };
+        if let Some(pipeline) = self.external.as_mut().filter(|_| !frame.title) {
+            pipeline.begin_frame(&state);
+        }
        let shadow_view = self
            .pack_post
            .as_ref()
@@ -8681,6 +8662,12 @@ impl Renderer {
                let native = self.native.as_ref().filter(|_| !frame.title)?;
                native.shadow.as_ref()?;
                native.frame.shadow_view(frame)
+            })
+            .or_else(|| {
+                self.external
+                    .as_ref()
+                    .filter(|_| !frame.title)?
+                    .shadow_request(&state)
            });
        // `LevelRenderer.extractSectionDrawGroups`' fade-in time, for the instances.
        let fade_ms = fade_millis(frame.chunk_fade);
@@ -9495,7 +9482,7 @@ impl Renderer {
                }
            };
            // A custom outline (PvP & HUD) takes the bright stroke's colour, scales both widths.
-            let (custom, scale) = frame.look.outline.map_or((None, 1.0), |o| (Some(o.0), o.1));
+            let (custom, scale) = frame.pvp.outline.map_or((None, 1.0), |(c, s)| (Some(c), s));
            if frame.outline_high_contrast {
                stroke(0xff00_0000, 7.0 * scale, lines);
                stroke(custom.unwrap_or(0xff57_ffe1), width * scale, lines);
@@ -10116,7 +10103,11 @@ impl Renderer {
        let pack_reads_world = pack_post || native_post;
        laps.lap("r_uploads");
        // Phase 2 of occlusion culling draws over the depth, and a shader pack or TAA reads it.
+        // Post effects (a resource pack's chains, `use_depth_buffer`) read the world's depth
+        // after the world pass, as `GameRenderer.render` hands them the main target's.
+        let post_reads_depth = !frame.title && !frame.post_effects.effects.is_empty();
        let keep_depth = pack_reads_world
+            || post_reads_depth
            || (taa && self.world_post.taa)
            || oit_on
            || native_render::render_needs().world_depth
@@ -12094,24 +12085,18 @@ impl Renderer {
                self.screenshot = Some(request);
            } else {
                self.screenshot_halvings = 0;
-                self.screenshot_hdr = None;
-                if let Some(hdr_buffer) = hdr_readback {
-                    let hdr_path = hdr_screenshot_path(&request.path);
-                    match self.write_hdr_screenshot(&hdr_path, &hdr_buffer) {
-                        Ok(()) => {
-                            log::info!("Saved HDR screenshot to {}", hdr_path.display());
-                            self.screenshot_hdr = Some(hdr_path);
-                        }
-                        Err(e) => log::warn!(
-                            "Horizon renderer: HDR screenshot {}: {e}",
-                            hdr_path.display()
-                        ),
-                    }
+                let size = [self.config.width, self.config.height];
+                let hdr = hdr_readback
+                    .filter(|_| self.hdr.is_some())
+                    .map(|b| (hdr_screenshot_path(&request.path), b));
+                let shot = screenshot_save::Shot::new(&request, size, self.config.format, hdr);
+                if request.background {
+                    self.screenshot_saves.start(shot, buffer);
+                } else {
+                    let saved = screenshot_save::save_now(&self.device, shot, &buffer);
+                    self.screenshot_hdr = saved.hdr;
+                    self.screenshot_result = Some(saved.result);
                }
-                self.screenshot_result = Some(
-                    self.write_screenshot(&request, &buffer)
-                        .map_err(|e| e.to_string()),
-                );
            }
        }
        // The frame's own waits for the submit thread (its queue writes and passes).
@@ -12714,96 +12699,22 @@ impl Renderer {
            let texture = copy.as_ref().unwrap_or(texture);
            Some((request, copy_frame(&self.device, encoder, texture, size)))
        } else {
-            self.screenshot_result = Some(Err(format!(
+            let error = format!(
                "screenshots need a 32-bit surface format, not {:?}",
                self.config.format
-            )));
+            );
+            if request.background {
+                self.saved_screenshots.push(screenshot_save::Saved {
+                    path: request.path,
+                    result: Err(error),
+                    hdr: None,
+                });
+            } else {
+                self.screenshot_result = Some(Err(error));
+            }
            None
        }
    }
-    /// The pixels `copy_frame` read back into `buffer`, 4 bytes each, row after row.
-    fn read_frame(&self, buffer: &wgpu::Buffer) -> Result<Vec<[u8; 4]>> {
-        let (sender, receiver) = std::sync::mpsc::channel();
-        buffer.map_async(wgpu::MapMode::Read, .., move |r| {
-            let _ = sender.send(r);
-        });
-        self.device
-            .poll(wgpu::PollType::wait_indefinitely())
-            .map_err(|e| e.to_string())?;
-        receiver
-            .recv()
-            .map_err(|e| e.to_string())?
-            .map_err(|e| e.to_string())?;
-        let (width, height, row) = (
-            self.config.width as usize,
-            self.config.height as usize,
-            padded_row(self.config.width) as usize,
-        );
-        let mut pixels = Vec::with_capacity(width * height);
-        {
-            let data = buffer.get_mapped_range(..).map_err(|e| e.to_string())?;
-            for y in 0..height {
-                pixels.extend_from_slice(data[y * row..y * row + width * 4].as_chunks::<4>().0);
-            }
-        }
-        buffer.unmap();
-        Ok(pixels)
-    }
-    fn write_screenshot(
-        &self,
-        request: &ScreenshotRequest,
-        buffer: &wgpu::Buffer,
-    ) -> Result<[u32; 2]> {
-        let bgra = matches!(
-            self.config.format.remove_srgb_suffix(),
-            wgpu::TextureFormat::Bgra8Unorm
-        );
-        let mut pixels = Vec::with_capacity((self.config.width * self.config.height * 4) as usize);
-        for px in self.read_frame(buffer)? {
-            let (r, b) = if bgra { (px[2], px[0]) } else { (px[0], px[2]) };
-            pixels.extend_from_slice(&[r, px[1], b, 255]);
-        }
-        // NativeImage.resizeSubRectTo on takeAutoScreenshot's grab: the icon
-        // is the frame's centre square averaged down to its size.
-        let (width, height, pixels) = match request.size {
-            Some(size) => (
-                size[0],
-                size[1],
-                square_downscale(&pixels, self.config.width, self.config.height, size),
-            ),
-            None => (self.config.width, self.config.height, pixels),
-        };
-        let mut encoder = png::Encoder::new(
-            std::io::BufWriter::new(std::fs::File::create(&request.path)?),
-            width,
-            height,
-        );
-        encoder.set_color(png::ColorType::Rgba);
-        encoder.set_depth(png::BitDepth::Eight);
-        encoder.write_header()?.write_image_data(&pixels)?;
-        Ok([width, height])
-    }
-    /// The HDR10 copy (`Hdr::capture`) as a 16-bit PNG tagged BT.2020 with PQ (cICP, PNG's
-    /// third edition), with the content light levels its pixels hold (cLLI), and
-    /// an ICC profile for the programs that don't read cICP (`hdr_icc`).
-    fn write_hdr_screenshot(&self, path: &std::path::Path, buffer: &wgpu::Buffer) -> Result<()> {
-        if self.hdr.is_none() {
-            return Ok(());
-        }
-        let pixels = hdr10_to_rgb16(&self.read_frame(buffer)?);
-        let mut info = png::Info::with_size(self.config.width, self.config.height);
-        info.color_type = png::ColorType::Rgb;
-        info.bit_depth = png::BitDepth::Sixteen;
-        info.icc_profile = Some(hdr_icc::profile().into());
-        let encoder =
-            png::Encoder::with_info(std::io::BufWriter::new(std::fs::File::create(path)?), info)?;
-        let mut writer = encoder.write_header()?;
-        // BT.2020 primaries, PQ, RGB, full range.
-        writer.write_chunk(png::chunk::cICP, &[9, 16, 0, 1])?;
-        writer.write_chunk(png::chunk::cLLI, &hdr_icc::content_light_levels(&pixels))?;
-        writer.write_image_data(&pixels)?;
-        Ok(())
-    }
 }
 /// `screenshots/2026-10-28_12.00.00.png` -> `screenshots/2026-10-28_12.00.00-hdr.png`.
 fn hdr_screenshot_path(path: &std::path::Path) -> PathBuf {
@@ -12888,61 +12799,6 @@ impl Cull for Frusta {
        self.0.contains(min, max) || self.1.is_some_and(|f| f.contains(min, max))
    }
 }
-/// A shader pack's shadow camera's box, and with `casters` only what can shade the camera's view
-/// (`shadow_casters`): a box must meet all of them.
-#[derive(Clone, Copy, Debug)]
-pub struct ShadowCull {
-    pub light: Frustum,
-    pub casters: Option<[Frustum; 2]>,
-    /// `shadowDistance × shadowDistanceRenderMul`: only what lies within this many blocks of the
-    /// camera along each axis, a cube around it. Our probe's Iris 1.11.7 maps keep the sections
-    /// whose box, grown by `SHADOW_CASTER_MARGIN` as for the casters, meets that cube (#8464):
-    /// out to its corners, and a section 1 block past its side but not one 1.5 blocks past.
-    pub reach: Option<f32>,
-}
-impl ShadowCull {
-    /// Whether the camera-relative box `min..max`, grown by the margin, meets (`whole`: lies
-    /// within) `reach`'s cube.
-    fn within_reach(&self, min: Vec3, max: Vec3, whole: bool) -> bool {
-        let (min, max) = (min - SHADOW_CASTER_MARGIN, max + SHADOW_CASTER_MARGIN);
-        self.reach.is_none_or(|d| {
-            if whole {
-                min.cmpge(Vec3::splat(-d)).all() && max.cmple(Vec3::splat(d)).all()
-            } else {
-                max.cmpge(Vec3::splat(-d)).all() && min.cmple(Vec3::splat(d)).all()
-            }
-        })
-    }
-}
-/// How far past a section's 16 blocks the shadow pass looks for what can shade the view: our
-/// probes' Iris 1.11.7 maps keep the sections whose box, grown by this much on every side, meets
-/// `shadow_casters`' shape. Over 76 scenes at fields of view 30 to 110, Iris keeps every section
-/// that needs up to 1.1224 blocks and drops every one that needs 1.1252 or more (#8464): one
-/// growth, whatever the field of view, of 9/8 (a fit, not Iris's code). Without it the edges of
-/// the wedge lose a column of terrain.
-const SHADOW_CASTER_MARGIN: f32 = 1.125;
-impl Cull for ShadowCull {
-    fn intersects(&self, min: Vec3, max: Vec3) -> bool {
-        let (grown_min, grown_max) = (min - SHADOW_CASTER_MARGIN, max + SHADOW_CASTER_MARGIN);
-        self.within_reach(min, max, false)
-            && self.light.intersects(min, max)
-            && self
-                .casters
-                .is_none_or(|c| c.iter().all(|f| f.intersects(grown_min, grown_max)))
-    }
-    fn contains(&self, min: Vec3, max: Vec3) -> bool {
-        let (grown_min, grown_max) = (min - SHADOW_CASTER_MARGIN, max + SHADOW_CASTER_MARGIN);
-        self.within_reach(min, max, true)
-            && self.light.contains(min, max)
-            && self
-                .casters
-                .is_none_or(|c| c.iter().all(|f| f.contains(grown_min, grown_max)))
-    }
-    /// Our probe's Iris 1.11.7 maps fit testing the casters' whole sections (a guess that matched).
-    fn tight(&self) -> bool {
-        self.casters.is_none()
-    }
-}
 /// The block entities of `sections` whose box, a block wider on every side, comes within the
 /// 64 blocks block entities are drawn to (`Renderer::visible_block_entities_in_frustum`).
 fn block_entities_within_reach<'a>(
@@ -12965,17 +12821,6 @@ fn block_entities_within_reach<'a>(
        })
        .flatten()
 }
-/// The shadow camera's box that the shadow pass draws terrain in: the sides of `view.cull`, and
-/// its near and far planes only with `depth_planes`.
-fn shadow_box(view: &pack_post::ShadowView) -> Frustum {
-    let mut planes = frustum(view.cull);
-    if !view.depth_planes {
-        // `frustum`'s faces at depth 0 and 1 take in everything.
-        planes[4] = Vec4::W;
-        planes[5] = Vec4::W;
-    }
-    Frustum { planes }
-}
 /// Camera-relative clip planes (`Frustum`).
 #[derive(Clone, Copy, Debug)]
 pub struct Frustum {
@@ -13099,21 +12944,6 @@ fn projection_center(view_proj: Mat4) -> Option<Vec3> {
    let b = DVec3::new(rows[0].w, rows[1].w, rows[2].w);
    Some((a.inverse() * -b).as_vec3())
 }
-/// The runs of a section's solid quads the shadow pass draws: every face within the unculled
-/// distance, or everywhere for `every_face`; else the quads that can face the light.
-fn shadow_runs(
-    sides: &Sides,
-    view: &pack_post::ShadowView,
-    origin: [f32; 3],
-    draw: impl FnMut(u32, u32),
-) {
-    let unculled = view.unculled.is_some_and(|d| {
-        let o = Vec3::from(origin) + 8.0;
-        o.x.abs().max(o.z.abs()) <= d + 8.0
-    });
-    let toward = (!unculled && !view.every_face).then_some(view.light * 1.0e5);
-    facing_runs(sides, toward, origin, draw);
-}

 /// Calls `draw(first, quads)` for each run of a mesh's solid quads that can
 /// face `eye` (`projection_center`), the mesh at the camera-relative
@@ -13140,68 +12970,6 @@ fn facing_runs_from(
        None => sides.every(part, draw),
    }
 }
-/// The camera's view `view_proj` (wgpu depth, reversed or not) stretched without end toward
-/// `light` (a direction): the boxes whose shadow, cast away from the light, can fall into the
-/// view. Its planes are the view's faces turned toward the light, and through each edge between
-/// such a face and one turned away, the plane along the light; unused ones take in everything.
-fn shadow_casters(view_proj: Mat4, light: Vec3) -> [Frustum; 2] {
-    let faces = frustum(view_proj);
-    let toward = faces.map(|p| p.truncate().dot(light) >= 0.0);
-    let inverse = view_proj.inverse();
-    // Corner (x, y, z) of clip space's box; `frustum`'s faces at x -1 and 1 are 0 and 1, at
-    // y -1 and 1 are 2 and 3, at depth 0 and 1 are 4 and 5.
-    let corner = |c: [usize; 3]| {
-        inverse.project_point3(Vec3::new(
-            c[0] as f32 * 2.0 - 1.0,
-            c[1] as f32 * 2.0 - 1.0,
-            c[2] as f32,
-        ))
-    };
-    let corners: Vec<[usize; 3]> = (0..8).map(|i| [i & 1, (i >> 1) & 1, i >> 2]).collect();
-    let centre = corners.iter().map(|&c| corner(c)).sum::<Vec3>() / 8.0;
-    let mut planes = [Vec4::W; 12];
-    let mut n = 0;
-    for (k, &face) in faces.iter().enumerate() {
-        if toward[k] {
-            planes[n] = face;
-            n += 1;
-        }
-    }
-    for a in &corners {
-        for axis in 0..3 {
-            if a[axis] == 1 {
-                continue;
-            }
-            let mut b = *a;
-            b[axis] = 1;
-            // The edge from a to b lies on the faces of the two other axes.
-            let [f, g] = [(axis + 1) % 3, (axis + 2) % 3].map(|o| o * 2 + a[o]);
-            if toward[f] == toward[g] {
-                continue;
-            }
-            let (p, q) = (corner(*a), corner(b));
-            let normal = (q - p).cross(light);
-            if normal.length_squared() < 1e-12 {
-                continue;
-            }
-            let normal = normal.normalize();
-            let side = if normal.dot(centre - p) < 0.0 {
-                -1.0
-            } else {
-                1.0
-            };
-            // At most six such edges with at most four faces toward the light: 12 planes.
-            if let Some(plane) = planes.get_mut(n) {
-                *plane = (normal * side).extend(-normal.dot(p) * side);
-                n += 1;
-            }
-        }
-    }
-    let [a, b] = [0, 6].map(|i| Frustum {
-        planes: planes[i..i + 6].try_into().expect("six planes"),
-    });
-    [a, b]
-}
 fn taa_frustum(view_proj: Mat4, rendered_size: [u32; 2]) -> Frustum {
    // TAA shifts clip x/y by at most half a rendered pixel times clip w.
    // Widen x/y before extracting the planes: this includes every such shifted
@@ -13714,6 +13482,7 @@ mod tests {
            Some(Reported {
                paper_white: 240,
                peak: 998,
+                peak_guessed: true,
            })
        );
        assert_eq!(
@@ -13721,6 +13490,7 @@ mod tests {
            Some(Reported {
                paper_white: 480,
                peak: 480,
+                peak_guessed: true,
            })
        );
        // White above the calibrated peak (a Samsung QD-OLED's 380, the slider at 456).
@@ -13729,6 +13499,7 @@ mod tests {
            Some(Reported {
                paper_white: 456,
                peak: 456,
+                peak_guessed: true,
            })
        );
        assert_eq!(os_reported(&info(Some(1000.0), None)), None);
@@ -15419,11 +15190,9 @@ fn log_os_reported(reported: Option<crate::graphics::Reported>) {
        None => "Horizon renderer: the system doesn't report the display's luminance".into(),
    });
 }
-/// What the OS reports in absolute nits (Windows: DXGI's `MaxLuminance` and the SDR
-/// white level the brightness slider sets), which is HDR output's scale there: SDR
-/// white is Paper White, the display's peak is Peak Brightness. Both are kept within
-/// the settings' ranges. The OS's figures often come from the display's EDID and may
-/// run optimistic; the player's own value always wins.
+/// What the OS reports in absolute nits, HDR output's scale (Windows: DXGI's SDR white level,
+/// the brightness slider's, as Paper White, and its `MaxLuminance`, mostly the display's EDID
+/// guess, as Peak Brightness), kept within the settings' ranges. The player's values win.
 fn os_reported(info: &wgpu::DisplayHdrInfo) -> Option<crate::graphics::Reported> {
    let luminance = info.luminance?;
    let usable = |n: f32| n.is_finite() && n > 0.0;
@@ -15435,6 +15204,7 @@ fn os_reported(info: &wgpu::DisplayHdrInfo) -> Option<crate::graphics::Reported>
        // Windows' SDR brightness slider can set white above the reported peak (480 against
        // a calibrated 380): the highlights then stay at white instead of dropping below it.
        peak: (peak.round() as u32).clamp(200, 10_000).max(paper_white),
+        peak_guessed: true,
    })
 }

@@ -15470,6 +15240,7 @@ fn reported(l: horizon_hdr::wayland::Luminances) -> crate::graphics::Reported {
    crate::graphics::Reported {
        paper_white: 203,
        peak: peak.clamp(200, 10_000),
+        peak_guessed: false,
    }
 }

@@ -15497,7 +15268,7 @@ mod shadow_face_tests {
    }

    /// The layers (faces) of the quads the shadow pass draws of `solid`.
-    fn drawn(view: &pack_post::ShadowView, origin: [f32; 3]) -> Vec<u16> {
+    fn drawn(view: &external::ShadowView, origin: [f32; 3]) -> Vec<u16> {
        let mut solid = block([7.0, 7.0, 7.0]);
        let sides = crate::mesher::sort_tinted(&mut solid, &mut Vec::new());
        let mut layers = Vec::new();
@@ -15510,8 +15281,8 @@ mod shadow_face_tests {
        layers
    }

-    fn view(every_face: bool) -> pack_post::ShadowView {
-        pack_post::ShadowView {
+    fn view(every_face: bool) -> external::ShadowView {
+        external::ShadowView {
            cull: Mat4::IDENTITY,
            light: Vec3::Y,
            distance: None,
@@ -15718,14 +15489,14 @@ mod shadow_caster_tests {
    #[test]
    fn the_shadow_pass_draws_terrain_outside_the_pack_s_planes() {
        let kept = |near: Option<f32>, far: Option<f32>, y: f64, min: [f32; 3], depth: bool| {
-            let shadow = horizon_render_pipeline::Shadow {
+            let shadow = horizon_shaders::Shadow {
                distance: 128.0,
                near,
                far,
-                ..horizon_render_pipeline::Shadow::default()
+                ..horizon_shaders::Shadow::default()
            };
            let camera = DVec3::new(13.5, y + 1.62, -13.5);
-            let view = pack_post::ShadowView {
+            let view = external::ShadowView {
                cull: pack_uniforms::shadow_culling_at(Vec3::Y, camera, &shadow),
                light: Vec3::Y,
                distance: None,
@@ -524,7 +524,7 @@ impl Scene {
            outline: Vec::new(),
            outline_after_terrain: false,
            outline_high_contrast: false,
-            look: Default::default(),
+            pvp: Default::default(),
            debug_lines: &[],
            debug_lines_on_top: &[],
            debug_crosshair: &[],
@@ -1,12 +1,11 @@
-//! OptiFine custom sky layers on the GPU: one texture per layer, kept with the renderer (its pack),
+//! Custom sky layers (`crate::custom_sky`) on the GPU: one texture per layer, kept with the renderer (its pack),
 //! a static skybox mesh of the 3x2 grid's six faces, and one pipeline per blend mode. A frame
 //! uploads one small uniform per drawn layer ([`crate::custom_sky::Draw`]) and draws 36 vertices
 //! each, after the vanilla sky's disc and sunrise and before the sun, moon and stars.
 use glam::Mat4;
-use horizon_optifine::sky::{Blend, Face};
 use wgpu::util::DeviceExt;

-use crate::custom_sky::{CustomSky as Pack, Draw};
+use crate::custom_sky::{Blend, Draw, SkyLayers};

 /// The blend modes in the shader's `mode` order (custom_sky.wgsl).
 const MODES: [Blend; 9] = [
@@ -85,6 +84,76 @@ fn blend(mode: Blend) -> wgpu::BlendComponent {
    }
 }

+/// A face of the skybox, as the 3x2 grid of its texture holds them: `Bottom`, `Top`, `South` in
+/// the top row, `West`, `North`, `East` below.
+#[derive(Clone, Copy, Debug, PartialEq, Eq)]
+enum Face {
+    Bottom,
+    Top,
+    South,
+    West,
+    North,
+    East,
+}
+
+impl Face {
+    const ALL: [Self; 6] = [
+        Self::Bottom,
+        Self::Top,
+        Self::South,
+        Self::West,
+        Self::North,
+        Self::East,
+    ];
+
+    /// The face's cell of the texture, `[u0, v0, u1, v1]` in 0..1.
+    fn cell(self) -> [f32; 4] {
+        let (col, row) = match self {
+            Self::Bottom => (0, 0),
+            Self::Top => (1, 0),
+            Self::South => (2, 0),
+            Self::West => (0, 1),
+            Self::North => (1, 1),
+            Self::East => (2, 1),
+        };
+        let (u, v) = (col as f32 / 3.0, row as f32 / 2.0);
+        [u, v, u + 1.0 / 3.0, v + 0.5]
+    }
+
+    /// The face's corners (on the unit cube around the camera; x east, y up, z south) in the
+    /// order of its cell's `(u0, v0)`, `(u1, v0)`, `(u1, v1)`, `(u0, v1)`. The side faces are
+    /// seen from inside with up at the top of their cell; the top face has north at the bottom of
+    /// its cell, the bottom face north at the top (the template's `N` marks).
+    fn corners(self) -> [[f32; 3]; 4] {
+        match self {
+            // Seen looking north: west on the left.
+            Self::North => [
+                [-1., 1., -1.],
+                [1., 1., -1.],
+                [1., -1., -1.],
+                [-1., -1., -1.],
+            ],
+            Self::South => [[1., 1., 1.], [-1., 1., 1.], [-1., -1., 1.], [1., -1., 1.]],
+            Self::East => [[1., 1., -1.], [1., 1., 1.], [1., -1., 1.], [1., -1., -1.]],
+            Self::West => [
+                [-1., 1., 1.],
+                [-1., 1., -1.],
+                [-1., -1., -1.],
+                [-1., -1., 1.],
+            ],
+            // Looking up with north toward the cell's bottom edge: east on the right.
+            Self::Top => [[-1., 1., 1.], [1., 1., 1.], [1., 1., -1.], [-1., 1., -1.]],
+            // Looking down with north toward the cell's top edge: east on the right.
+            Self::Bottom => [
+                [-1., -1., -1.],
+                [1., -1., -1.],
+                [1., -1., 1.],
+                [-1., -1., 1.],
+            ],
+        }
+    }
+}
+
 /// The skybox's 36 vertices: two triangles per face, each corner with its cell's UV.
 fn mesh() -> Vec<Vertex> {
    let mut out = Vec::with_capacity(36);
@@ -256,10 +325,15 @@ impl CustomSky {
    }

    /// The pack's layer textures, replacing any before.
-    pub(super) fn set_pack(&mut self, device: &wgpu::Device, queue: &wgpu::Queue, pack: &Pack) {
+    pub(super) fn set_pack(
+        &mut self,
+        device: &wgpu::Device,
+        queue: &wgpu::Queue,
+        pack: &dyn SkyLayers,
+    ) {
        let limit = device.limits().max_texture_dimension_2d;
        self.groups = pack
-            .images
+            .images()
            .iter()
            .map(|image| {
                // Too large for this GPU: a 1x1 transparent texel, so the layer draws nothing.
@@ -413,6 +487,38 @@ impl CustomSky {
 mod tests {
    use super::*;

+    #[test]
+    fn the_grid_holds_each_face_once_and_faces_point_out() {
+        let mut cells: Vec<_> = Face::ALL
+            .iter()
+            .map(|f| f.cell().map(|x| (x * 6.0) as i32))
+            .collect();
+        cells.dedup();
+        assert_eq!(cells.len(), 6);
+        assert_eq!(Face::East.cell(), [2.0 / 3.0, 0.5, 1.0, 1.0]);
+        for face in Face::ALL {
+            let c = face.corners();
+            let sub = |a: [f32; 3], b: [f32; 3]| [a[0] - b[0], a[1] - b[1], a[2] - b[2]];
+            let (a, b) = (sub(c[1], c[0]), sub(c[3], c[0]));
+            let n = [
+                a[1] * b[2] - a[2] * b[1],
+                a[2] * b[0] - a[0] * b[2],
+                a[0] * b[1] - a[1] * b[0],
+            ];
+            let centre: [f32; 3] =
+                std::array::from_fn(|i| c.iter().map(|p| p[i]).sum::<f32>() / 4.0);
+            // Seen from inside, u runs right and v down, so u x v points away from the camera.
+            let dot: f32 = (0..3).map(|i| n[i] * centre[i]).sum();
+            assert!(dot > 0.0, "{face:?} is mirrored");
+        }
+        // The top cell's bottom edge (v1) is north: its corners 2 and 3 have z = -1.
+        assert_eq!(Face::Top.corners()[2][2], -1.0);
+        assert_eq!(Face::Top.corners()[3][2], -1.0);
+        // The bottom cell's top edge (v0) is north.
+        assert_eq!(Face::Bottom.corners()[0][2], -1.0);
+        assert_eq!(Face::Bottom.corners()[1][2], -1.0);
+    }
+
    /// What a blend leaves a sky texel of `dst` with when the shader outputs `src`
    /// (custom_sky.wgsl) for a layer texel `t` at brightness `b`, per channel.
    fn mix(mode: Blend, dst: f32, t: f32, a: f32, b: f32) -> f32 {
@@ -6,7 +6,7 @@ struct Layer {
    // Projection * view (camera-relative) * the layer's rotation.
    clip_from_sky: mat4x4<f32>,
    brightness: f32,
-    // horizon_optifine::sky::Blend, in gfx/custom_sky.rs's MODES order.
+    // crate::custom_sky::Blend, in gfx/custom_sky.rs's MODES order.
    mode: u32,
    pad: vec2<u32>,
    hdr_settings: vec4<f32>,
@@ -0,0 +1,214 @@
+//! The hook an external shader pipeline fills (#14035, layer plan M6). A shader pack's runtime
+//! (a platform crate, later) implements [`ExternalPipeline`]; the renderer calls it at fixed
+//! points of a world frame and draws vanilla's way wherever it doesn't answer. With none set
+//! (`Renderer::set_external_pipeline`), each point is one `Option` test.
+//!
+//! Workspace-internal: the trait names the engine's frame, its mesh format and its pass order,
+//! has one implementer in this workspace, carries no stability promise and is never exposed to
+//! mods. A mesher or pass change updates its implementer in the same PR. HDR output
+//! (`output.rs`, `frame_policy`) is not an implementer: it stays the one output stage after the
+//! frame, and a pipeline draws into the frame it gives.
+//!
+//! Shadows are an engine frame point, on request: a pipeline that wants a shadow pass answers
+//! [`ShadowView`], the engine culls the sections from it ([`ShadowCull`]) and hands back the
+//! terrain seen from the light. Vanilla's path never asks, so it never computes shadow
+//! visibility.
+
+use glam::{Mat4, Vec3, Vec4};
+
+use super::{Cull, EffectiveOutput, Frame, Frustum, Sides, facing_runs, frustum};
+
+/// What a world frame gives an external pipeline at its points: the frame's own values, and
+/// the display's from the renderer's one output snapshot (`EffectiveOutput`: whether HDR is on,
+/// paper white, peak), never worked out again, so each split-screen window keeps its own.
+pub struct FrameState<'a> {
+    pub frame: &'a Frame<'a>,
+    pub output: &'a EffectiveOutput,
+}
+
+/// An external shader pipeline, called by the renderer at fixed points of a world frame (not
+/// title frames). Every method has a default that leaves vanilla's way in place.
+pub trait ExternalPipeline: Send {
+    /// A world frame starts, before culling.
+    fn begin_frame(&mut self, _state: &FrameState<'_>) {}
+    /// The shadow pass this frame wants; `None` draws none.
+    fn shadow_request(&self, _state: &FrameState<'_>) -> Option<ShadowView> {
+        None
+    }
+    /// The window's drawable size changed.
+    fn resize(&mut self, _size: [u32; 2]) {}
+    /// Forget what was kept from earlier frames: the next is drawn as a fresh pipeline's first.
+    fn reset_history(&mut self) {}
+}
+
+/// What the shadow camera sees of the terrain, for the game's draw lists: its view and
+/// projection in wgpu's clip space, the direction toward the light, and how far from the camera
+/// terrain is drawn (`shadowDistanceRenderMul`).
+pub struct ShadowView {
+    pub cull: glam::Mat4,
+    pub light: glam::Vec3,
+    pub distance: Option<f32>,
+    /// Draw everything, every face, within this many blocks (`shadow.culling=false|reversed`):
+    /// packs that voxelize the world in their shadow pass need all of it.
+    pub unculled: Option<f32>,
+    /// Every face of the drawn sections, not only those that can face the light. Iris 1.11.7's
+    /// shadow map holds the faces turned away from the light too (#9033): under a hill at low sun
+    /// a cave's ceiling, which faces away, is often all that shadows the cave.
+    pub every_face: bool,
+    /// Only the sections whose shadow can fall into the camera's view: those the camera's
+    /// frustum, stretched toward the light, takes in (`shadow_casters`). Our probes' Iris 1.11.7
+    /// maps fit keeping only those with `shadow.culling` unset (#8464): under a noon sun, only
+    /// the terrain above the ground the camera sees; with a low sun ahead, none behind the camera.
+    pub view_casters: bool,
+    /// Whether the projection's near and far planes in `cull` drop sections too. Our probes'
+    /// Iris 1.11.7 maps hold the terrain at every depth we put it along the light (from 535 blocks
+    /// beyond the shadow camera to about 120 before it), whatever `shadowNearPlane` and
+    /// `shadowFarPlane` the pack sets, or none (#10403): only its sides cull.
+    pub depth_planes: bool,
+}
+
+/// A shader pack's shadow camera's box, and with `casters` only what can shade the camera's view
+/// (`shadow_casters`): a box must meet all of them.
+#[derive(Clone, Copy, Debug)]
+pub struct ShadowCull {
+    pub light: Frustum,
+    pub casters: Option<[Frustum; 2]>,
+    /// `shadowDistance × shadowDistanceRenderMul`: only what lies within this many blocks of the
+    /// camera along each axis, a cube around it. Our probe's Iris 1.11.7 maps keep the sections
+    /// whose box, grown by `SHADOW_CASTER_MARGIN` as for the casters, meets that cube (#8464):
+    /// out to its corners, and a section 1 block past its side but not one 1.5 blocks past.
+    pub reach: Option<f32>,
+}
+impl ShadowCull {
+    /// Whether the camera-relative box `min..max`, grown by the margin, meets (`whole`: lies
+    /// within) `reach`'s cube.
+    fn within_reach(&self, min: Vec3, max: Vec3, whole: bool) -> bool {
+        let (min, max) = (min - SHADOW_CASTER_MARGIN, max + SHADOW_CASTER_MARGIN);
+        self.reach.is_none_or(|d| {
+            if whole {
+                min.cmpge(Vec3::splat(-d)).all() && max.cmple(Vec3::splat(d)).all()
+            } else {
+                max.cmpge(Vec3::splat(-d)).all() && min.cmple(Vec3::splat(d)).all()
+            }
+        })
+    }
+}
+/// How far past a section's 16 blocks the shadow pass looks for what can shade the view: our
+/// probes' Iris 1.11.7 maps keep the sections whose box, grown by this much on every side, meets
+/// `shadow_casters`' shape. Over 76 scenes at fields of view 30 to 110, Iris keeps every section
+/// that needs up to 1.1224 blocks and drops every one that needs 1.1252 or more (#8464): one
+/// growth, whatever the field of view, of 9/8 (a fit, not Iris's code). Without it the edges of
+/// the wedge lose a column of terrain.
+const SHADOW_CASTER_MARGIN: f32 = 1.125;
+impl Cull for ShadowCull {
+    fn intersects(&self, min: Vec3, max: Vec3) -> bool {
+        let (grown_min, grown_max) = (min - SHADOW_CASTER_MARGIN, max + SHADOW_CASTER_MARGIN);
+        self.within_reach(min, max, false)
+            && self.light.intersects(min, max)
+            && self
+                .casters
+                .is_none_or(|c| c.iter().all(|f| f.intersects(grown_min, grown_max)))
+    }
+    fn contains(&self, min: Vec3, max: Vec3) -> bool {
+        let (grown_min, grown_max) = (min - SHADOW_CASTER_MARGIN, max + SHADOW_CASTER_MARGIN);
+        self.within_reach(min, max, true)
+            && self.light.contains(min, max)
+            && self
+                .casters
+                .is_none_or(|c| c.iter().all(|f| f.contains(grown_min, grown_max)))
+    }
+    /// Our probe's Iris 1.11.7 maps fit testing the casters' whole sections (a guess that matched).
+    fn tight(&self) -> bool {
+        self.casters.is_none()
+    }
+}
+/// The shadow camera's box that the shadow pass draws terrain in: the sides of `view.cull`, and
+/// its near and far planes only with `depth_planes`.
+pub(super) fn shadow_box(view: &ShadowView) -> Frustum {
+    let mut planes = frustum(view.cull);
+    if !view.depth_planes {
+        // `frustum`'s faces at depth 0 and 1 take in everything.
+        planes[4] = Vec4::W;
+        planes[5] = Vec4::W;
+    }
+    Frustum { planes }
+}
+
+/// The runs of a section's solid quads the shadow pass draws: every face within the unculled
+/// distance, or everywhere for `every_face`; else the quads that can face the light.
+pub(super) fn shadow_runs(
+    sides: &Sides,
+    view: &ShadowView,
+    origin: [f32; 3],
+    draw: impl FnMut(u32, u32),
+) {
+    let unculled = view.unculled.is_some_and(|d| {
+        let o = Vec3::from(origin) + 8.0;
+        o.x.abs().max(o.z.abs()) <= d + 8.0
+    });
+    let toward = (!unculled && !view.every_face).then_some(view.light * 1.0e5);
+    facing_runs(sides, toward, origin, draw);
+}
+
+/// The camera's view `view_proj` (wgpu depth, reversed or not) stretched without end toward
+/// `light` (a direction): the boxes whose shadow, cast away from the light, can fall into the
+/// view. Its planes are the view's faces turned toward the light, and through each edge between
+/// such a face and one turned away, the plane along the light; unused ones take in everything.
+pub(super) fn shadow_casters(view_proj: Mat4, light: Vec3) -> [Frustum; 2] {
+    let faces = frustum(view_proj);
+    let toward = faces.map(|p| p.truncate().dot(light) >= 0.0);
+    let inverse = view_proj.inverse();
+    // Corner (x, y, z) of clip space's box; `frustum`'s faces at x -1 and 1 are 0 and 1, at
+    // y -1 and 1 are 2 and 3, at depth 0 and 1 are 4 and 5.
+    let corner = |c: [usize; 3]| {
+        inverse.project_point3(Vec3::new(
+            c[0] as f32 * 2.0 - 1.0,
+            c[1] as f32 * 2.0 - 1.0,
+            c[2] as f32,
+        ))
+    };
+    let corners: Vec<[usize; 3]> = (0..8).map(|i| [i & 1, (i >> 1) & 1, i >> 2]).collect();
+    let centre = corners.iter().map(|&c| corner(c)).sum::<Vec3>() / 8.0;
+    let mut planes = [Vec4::W; 12];
+    let mut n = 0;
+    for (k, &face) in faces.iter().enumerate() {
+        if toward[k] {
+            planes[n] = face;
+            n += 1;
+        }
+    }
+    for a in &corners {
+        for axis in 0..3 {
+            if a[axis] == 1 {
+                continue;
+            }
+            let mut b = *a;
+            b[axis] = 1;
+            // The edge from a to b lies on the faces of the two other axes.
+            let [f, g] = [(axis + 1) % 3, (axis + 2) % 3].map(|o| o * 2 + a[o]);
+            if toward[f] == toward[g] {
+                continue;
+            }
+            let (p, q) = (corner(*a), corner(b));
+            let normal = (q - p).cross(light);
+            if normal.length_squared() < 1e-12 {
+                continue;
+            }
+            let normal = normal.normalize();
+            let side = if normal.dot(centre - p) < 0.0 {
+                -1.0
+            } else {
+                1.0
+            };
+            // At most six such edges with at most four faces toward the light: 12 planes.
+            if let Some(plane) = planes.get_mut(n) {
+                *plane = (normal * side).extend(-normal.dot(p) * side);
+                n += 1;
+            }
+        }
+    }
+    let [a, b] = [0, 6].map(|i| Frustum {
+        planes: planes[i..i + 6].try_into().expect("six planes"),
+    });
+    [a, b]
+}
@@ -191,7 +191,7 @@ pub struct Hdr {
    pub masks: Masks,
    /// HDR lighting, whether Horizon lifts this frame's world: off under a Horizon shader pack
    /// that draws, while a `shaders/` pack's post or material stage runs (the pack's own),
-    /// with HDR Lighting (`look`) off, and with `HORIZON_HDR_LIGHTING=0`, to compare.
+    /// and with HDR Lighting (`look`) off.
    pub lighting: bool,
    /// The HDR Lighting setting: off, nothing in the world is lifted, light sources and the
    /// sun included, so the picture is SDR's on the HDR canvas.
@@ -1001,12 +1001,14 @@ impl Hdr {
    }
 }

-/// Horizon's icon (horizon-theme) as a 1-bit mask: its white strokes, one colour with hard
-/// edges, are the logo; everything else is not.
+/// The windows' icon (`window::set_icon_png`: Horizon's in the official game) as a 1-bit mask:
+/// its white strokes, one colour with hard edges, are the logo; everything else is not. No icon
+/// given: an empty mask.
 fn logo_mask(device: &wgpu::Device, queue: &wgpu::Queue) -> wgpu::TextureView {
    use wgpu::util::DeviceExt;
-    let (w, h, rgba) =
-        crate::hud::decode_bytes(horizon_theme::ICON_PNG).unwrap_or((1, 1, vec![0; 4]));
+    let (w, h, rgba) = horizon_client_input::window::icon_png()
+        .and_then(|png| crate::hud::decode_bytes(png).ok())
+        .unwrap_or((1, 1, vec![0; 4]));
    let mask: Vec<u8> = rgba
        .as_chunks::<4>()
        .0
@@ -338,7 +338,7 @@ pub struct NativeFrame {
    reflection_sampler: wgpu::Sampler,
    /// The shadow map the stages read, and the camera that draws it when the pack asks for one.
    pub shadow_map: super::native_shadow::ShadowMap,
-    shadow_camera: Option<horizon_render_pipeline::Shadow>,
+    shadow_camera: Option<horizon_shaders::Shadow>,
    /// Whether the pack's material reads `reflection` (`NativePack::new`): else no mirror
    /// is drawn and `has_reflection` stays 0.
    pub reflects: bool,
@@ -1497,7 +1497,7 @@ pub fn frame_inputs(
    size: [u32; 2],
    seconds: f32,
    index: u32,
-    shadow: Option<&horizon_render_pipeline::Shadow>,
+    shadow: Option<&horizon_shaders::Shadow>,
 ) -> FrameInputs {
    let aspect = size[0] as f32 / size[1].max(1) as f32;
    let view = crate::camera::view_matrix(frame.yaw, frame.pitch);
@@ -6,8 +6,8 @@
 //! draw lists (`ShadowView`) serve both; the map's texels are distorted toward the camera as the
 //! prelude's `shadow_position` undoes.

-use horizon_render_pipeline::Shadow;
 use horizon_shader_api::{Api, Frame as FrameInputs, manifest::Shadow as Settings, stages::GROUP};
+use horizon_shaders::Shadow;

 use super::native_material::TerrainShape;
 use super::wgsl_prefix::{TERRAIN, prefixed, section};
@@ -0,0 +1,59 @@
+//! `move_off_page`, moved out of `gfx.rs` unchanged.
+use super::*;
+
+/// `Renderer::compact_arena`'s and `shrink_translucent`'s moves: what the meshes
+/// hold on `page` of `arena` (`part`) goes to its other pages in video memory,
+/// until the next range would pass `budget` bytes (it keeps what is left; the
+/// first range moves whatever its size, so none keeps the page closed), the
+/// copies into `encoder`, the ranges' flat draw ids (`flat`) and, in the
+/// section arena, GPU culling's records (`records`) along. False when the other
+/// pages have no room left.
+pub(super) fn move_off_page<'a>(
+    arena: &mut arena::Arena,
+    encoder: &mut wgpu::CommandEncoder,
+    mut flat: Option<(&mut flat::Flat, &wgpu::Device, &mut upload::Uploads)>,
+    mut records: Option<&mut gpu_culling::Records>,
+    meshes: impl Iterator<Item = &'a mut SectionGpu>,
+    page: u32,
+    part: Part,
+    budget: &mut u64,
+) -> bool {
+    debug_assert!(
+        records.is_none() || matches!(part, Part::Section { .. }),
+        "records follow the section arena's ranges"
+    );
+    let mut moved = false;
+    for s in meshes {
+        // Nothing of a mesh here: split, one without solid quads (its (0, 0) is no
+        // range of page 0); in the other arenas, one without translucent quads.
+        let Some((_, start, vertices)) = part.of(s).filter(|r| r.0 == page) else {
+            continue;
+        };
+        let bytes = vertices * arena.stride();
+        if moved && bytes > *budget {
+            break;
+        }
+        let Some(to) = arena.alloc_moved(vertices) else {
+            return false;
+        };
+        arena.copy(encoder, (page, start), to, vertices);
+        arena.release(page, start, vertices);
+        if let (Some((flat, device, uploads)), Some(id)) = (&mut flat, s.flat_id) {
+            let key = match part {
+                Part::Translucent => to.0 + flat::TRANSLUCENT_KEYS,
+                _ => to.0,
+            };
+            flat.place(device, encoder, uploads, id, key, to.1, vertices);
+        }
+        part.set(s, to);
+        // Its solid quads start the range in either layout.
+        if let (Part::Section { .. }, Some(records), Some(id)) =
+            (part, records.as_deref_mut(), s.gpu_id)
+        {
+            records.relocate(id, to.0, u64::from(s.solid_base()));
+        }
+        *budget = budget.saturating_sub(bytes);
+        moved = true;
+    }
+    true
+}
@@ -144,6 +144,9 @@ pub struct EffectiveOutput {
    pub(crate) nits: [f32; 3],
    /// The HUD and menus' brightness, as a share of paper white: their nits over its.
    pub(crate) ui_brightness: f32,
+    /// The running shader pack lights the world itself: Horizon lifts none of it, so HDR
+    /// Lighting has nothing to switch (`with_pack`).
+    pub(crate) pack_lights: bool,
 }
 impl Default for EffectiveOutput {
    fn default() -> Self {
@@ -166,7 +169,22 @@ impl EffectiveOutput {
        },
        nits: [203.0, 1000.0, 0.0],
        ui_brightness: 1.0,
+        pack_lights: false,
    };
+    /// This output under the running shader pack: a `shaders/` one (`shaders`), or one of
+    /// Horizon's own of API `native`. Under a 0.1 pack on the 8- or 16-bit frame the last pass
+    /// still lifts the light sources and the sun its marks hold (`lifts_world` in
+    /// `Renderer::render`); under the rest Horizon lifts nothing.
+    pub(crate) fn with_pack(self, shaders: bool, native: Option<horizon_shader_api::Api>) -> Self {
+        let pack_lights = shaders
+            || native.is_some_and(|api| {
+                api != horizon_shader_api::Api::V0_1 || self.frame.format == super::LINEAR_FRAME
+            });
+        Self {
+            pack_lights,
+            ..self
+        }
+    }
    /// Whether the destination offers HDR output.
    pub fn hdr_offered(&self) -> bool {
        self.offered.is_some()
@@ -273,6 +291,7 @@ pub(crate) fn resolve_output(
        ],
        ui_brightness: settings.ui_nits(reading.luminance) as f32
            / settings.paper_white_nits(reading.luminance) as f32,
+        pack_lights: false,
    }
 }

@@ -300,6 +319,7 @@ pub(crate) mod tests {
                luminance: Some(Reported {
                    paper_white: 400,
                    peak: 1000,
+                    peak_guessed: false,
                }),
                hdr: system,
            },
@@ -650,6 +670,7 @@ pub(crate) mod tests {
        window_reading.luminance = Some(Reported {
            paper_white: 300,
            peak: 800,
+            peak_guessed: false,
        });
        assert_eq!(window_output(window_reading).nits[..2], [300.0, 800.0]);
        assert_eq!(
@@ -549,6 +549,7 @@ mod tests {
        reading.luminance = Some(Reported {
            paper_white: 250,
            peak: 600,
+            peak_guessed: false,
        });
        // 150 nits under the reported paper white of 250: 0.6 of it.
        settings.hdr_ui_nits = 150;
@@ -584,6 +585,7 @@ mod tests {
            reading.luminance = Some(Reported {
                paper_white,
                peak: 1000,
+                peak_guessed: false,
            });
            let next = candidate(&settings, caps, reading, &published);
            let again = commit(&mut swapchain, &published, next, caps, &mut rejected);
@@ -729,6 +731,7 @@ mod tests {
                luminance: (hdr == Some(true)).then_some(Reported {
                    paper_white: 300,
                    peak: 800,
+                    peak_guessed: false,
                }),
                hdr,
            };
@@ -4,8 +4,7 @@

 use std::collections::BTreeMap;

-use horizon_render_pipeline::{Format, Kind};
-use horizon_shaders::{BufferObject, CustomImage};
+use horizon_shaders::{BufferObject, CustomImage, Format, Kind};

 pub(super) struct PackImage {
    pub(super) def: CustomImage,
@@ -18,8 +18,7 @@
 use std::collections::HashMap;

 use glam::{DMat4, DVec3};
-use horizon_render_pipeline::{BUFFERS, Format, Kind, SHADOW_COLORS};
-use horizon_shaders::{Group, Post};
+use horizon_shaders::{BUFFERS, Format, Group, Kind, Post, SHADOW_COLORS};
 use smallvec::SmallVec;

 use super::pack_draw::DrawUniforms;
@@ -893,7 +892,7 @@ fn depth_linear(interface: &horizon_shaders::Interface, linear: u8) -> [f32; 4]
 }

 fn source(name: &str, shadow_space: bool, shadow_pass: bool, watershadow: bool) -> Source {
-    let shadow_color = horizon_render_pipeline::shadow_color(name);
+    let shadow_color = horizon_shaders::shadow_color(name);
    let shadow_depth = match name {
        "shadowtex0" | "watershadow" | "shadowtex0HW" => Some(0),
        "shadowtex1" | "shadowtex1HW" => Some(1),
@@ -912,7 +911,7 @@ fn source(name: &str, shadow_space: bool, shadow_pass: bool, watershadow: bool)
            };
        }
    }
-    if shadow_space && horizon_render_pipeline::buffer_index(name).is_some() {
+    if shadow_space && horizon_shaders::buffer_index(name).is_some() {
        // colortex buffers are not this pass's.
        return Source::Dummy;
    }
@@ -926,7 +925,7 @@ fn source(name: &str, shadow_space: bool, shadow_pass: bool, watershadow: bool)
        "normals" => Source::Normals,
        "specular" => Source::Specular,
        horizon_shaders::WATER_MASK => Source::WaterMask,
-        n => horizon_render_pipeline::buffer_index(n).map_or(Source::Dummy, Source::Color),
+        n => horizon_shaders::buffer_index(n).map_or(Source::Dummy, Source::Color),
    }
 }

@@ -1202,31 +1201,7 @@ pub(super) type TerrainDraw<'a> = dyn FnMut(
        Option<(u32, &wgpu::BindGroupLayout)>,
    ) + 'a;

-/// What the shadow camera sees of the terrain, for the game's draw lists: its view and
-/// projection in wgpu's clip space, the direction toward the light, and how far from the camera
-/// terrain is drawn (`shadowDistanceRenderMul`).
-pub(super) struct ShadowView {
-    pub cull: glam::Mat4,
-    pub light: glam::Vec3,
-    pub distance: Option<f32>,
-    /// Draw everything, every face, within this many blocks (`shadow.culling=false|reversed`):
-    /// packs that voxelize the world in their shadow pass need all of it.
-    pub unculled: Option<f32>,
-    /// Every face of the drawn sections, not only those that can face the light. Iris 1.11.7's
-    /// shadow map holds the faces turned away from the light too (#9033): under a hill at low sun
-    /// a cave's ceiling, which faces away, is often all that shadows the cave.
-    pub every_face: bool,
-    /// Only the sections whose shadow can fall into the camera's view: those the camera's
-    /// frustum, stretched toward the light, takes in (`shadow_casters`). Our probes' Iris 1.11.7
-    /// maps fit keeping only those with `shadow.culling` unset (#8464): under a noon sun, only
-    /// the terrain above the ground the camera sees; with a low sun ahead, none behind the camera.
-    pub view_casters: bool,
-    /// Whether the projection's near and far planes in `cull` drop sections too. Our probes'
-    /// Iris 1.11.7 maps hold the terrain at every depth we put it along the light (from 535 blocks
-    /// beyond the shadow camera to about 120 before it), whatever `shadowNearPlane` and
-    /// `shadowFarPlane` the pack sets, or none (#10403): only its sides cull.
-    pub depth_planes: bool,
-}
+pub(super) use super::external::ShadowView;

 /// An arena page's key, native vertices and optional per-quad source records.
 pub(super) type TerrainPage = (u32, wgpu::Buffer, Option<wgpu::Buffer>);
@@ -1583,7 +1558,7 @@ fn bindings(
            !unbound
                && (t.stage != pack_textures::stage(group)
                    || released.0 != t.stage
-                    || horizon_render_pipeline::buffer_index(&t.name)
+                    || horizon_shaders::buffer_index(&t.name)
                        .is_none_or(|b| released.1 & 1 << b == 0))
        });
        let image = pack
@@ -2433,7 +2408,7 @@ impl PackPost {
        let shadow_config = post.config.shadow.clone();
        let noise_size = post.config.noise_resolution.unwrap_or(256);
        let half_lives = post.config.half_lives;
-        for (name, ticks) in horizon_render_pipeline::HALF_LIVES.iter().zip(half_lives) {
+        for (name, ticks) in horizon_shaders::HALF_LIVES.iter().zip(half_lives) {
            if let Some(t) = ticks {
                notes.push(format!("`{name}` is {t} ticks"));
            }
@@ -602,7 +602,7 @@ pub(super) fn fixture_frame(hud: &HudBatch) -> Frame<'_> {
        outline: Vec::new(),
        outline_after_terrain: false,
        outline_high_contrast: false,
-        look: Default::default(),
+        pvp: Default::default(),
        debug_lines: &[],
        debug_lines_on_top: &[],
        debug_crosshair: &[],
@@ -440,7 +440,7 @@ fn fixture_frame(hud: &HudBatch) -> Frame<'_> {
        outline: Vec::new(),
        outline_after_terrain: false,
        outline_high_contrast: false,
-        look: Default::default(),
+        pvp: Default::default(),
        debug_lines: &[],
        debug_lines_on_top: &[],
        debug_crosshair: &[],
@@ -10,7 +10,7 @@
 //! a fit to one driver's values, not a rule Iris states. `RGBA4` and `RGBA2` read back the `RGBA8`
 //! bytes in the same probe, as Horizon's 8-bit buffers already do.

-use horizon_render_pipeline::{Format, Kind};
+use horizon_shaders::{Format, Kind};
 use naga::{BinaryOperator, Expression, Literal, MathFunction, Statement, VectorSize};

 /// The bits each channel keeps in a buffer of format `f`, for the formats that keep fewer than
@@ -409,7 +409,7 @@ fn frame(hud: &HudBatch) -> Frame<'_> {
        outline: Vec::new(),
        outline_after_terrain: false,
        outline_high_contrast: false,
-        look: Default::default(),
+        pvp: Default::default(),
        debug_lines: &[],
        debug_lines_on_top: &[],
        debug_crosshair: &[],
@@ -3,7 +3,7 @@
 //! with two sides that `shadowcomp` programs flip as composite programs flip colortex (6.1.6).
 //! Square, `shadowMapResolution` pixels.

-use horizon_render_pipeline::SHADOW_COLORS;
+use horizon_shaders::SHADOW_COLORS;

 type Ops<T> = wgpu::Operations<T>;
 type Color = wgpu::Color;
@@ -97,11 +97,7 @@ pub(super) fn stand_in(device: &wgpu::Device) -> wgpu::TextureView {
 }

 impl ShadowTargets {
-    pub fn reset_history(
-        &mut self,
-        device: &wgpu::Device,
-        shadow: &horizon_render_pipeline::Shadow,
-    ) {
+    pub fn reset_history(&mut self, device: &wgpu::Device, shadow: &horizon_shaders::Shadow) {
        let mut colors = 0;
        let mut doubled = 0;
        let formats = std::array::from_fn(|n| match &self.color[n] {
@@ -129,7 +125,7 @@ impl ShadowTargets {
    /// resolution is kept within the device's limit.
    pub fn new(
        device: &wgpu::Device,
-        shadow: &horizon_render_pipeline::Shadow,
+        shadow: &horizon_shaders::Shadow,
        formats: [wgpu::TextureFormat; SHADOW_COLORS],
        colors: u16,
        doubled: u16,
@@ -1,8 +1,7 @@
 //! A shader pack's custom textures (`texture.<stage>.<name>`, `texture.noise`) on the GPU, and
 //! which of them a program's sampler reads.

-use horizon_render_pipeline::Kind;
-use horizon_shaders::{CustomTexture, Group, Texels, Texture, TextureDim, TextureSource};
+use horizon_shaders::{CustomTexture, Group, Kind, Texels, Texture, TextureDim, TextureSource};

 /// What a custom texture is once uploaded: an image of ours, or one the game already has.
 pub(super) enum Image {
@@ -119,12 +118,12 @@ pub(super) fn find(textures: &[PackTexture], group: Group, ty: &str, name: &str)
    } else {
        wgpu::TextureViewDimension::D2
    };
-    let buffer = horizon_render_pipeline::buffer_index(name);
+    let buffer = horizon_shaders::buffer_index(name);
    let staged = textures.iter().position(|t| {
        t.stage == stage(group)
            && t.dimension == dimension
            && (t.name == name
-                || buffer.is_some() && horizon_render_pipeline::buffer_index(&t.name) == buffer)
+                || buffer.is_some() && horizon_shaders::buffer_index(&t.name) == buffer)
    });
    staged.or_else(|| {
        textures.iter().position(|t| {
@@ -28,7 +28,7 @@
 //! [-w, w], and the depth buffers packs read hold GL window depth.

 use glam::{DMat4, DVec3, Mat4, Vec3, Vec4};
-use horizon_render_pipeline::Shadow;
+use horizon_shaders::Shadow;

 use super::Frame;

@@ -440,7 +440,7 @@ pub struct FrameUniforms {
    center_depth: Option<f32>,
    /// The pack's shadow settings (7.1).
    pub shadow: Shadow,
-    /// The pack's smoothing half-lives in ticks (`horizon_render_pipeline::HALF_LIVES`).
+    /// The pack's smoothing half-lives in ticks (`horizon_shaders::HALF_LIVES`).
    pub half_lives: [Option<f32>; 4],
 }

@@ -2664,7 +2664,7 @@ pub(super) mod initial_history_tests {
            outline: Vec::new(),
            outline_after_terrain: false,
            outline_high_contrast: false,
-            look: Default::default(),
+            pvp: Default::default(),
            debug_lines: &[],
            debug_lines_on_top: &[],
            debug_crosshair: &[],
@@ -0,0 +1,79 @@
+//! Hardware ray queries, only on request (#13780, after the #1180 spike): `HORIZON_RAY_TRACING=1`
+//! at startup asks the device for wgpu's `EXPERIMENTAL_RAY_QUERY` when the GPU has it. Nothing
+//! draws with it yet. Without the variable, and in a build without `horizon-extras` (a Horizon
+//! extra, docs/layers.md), the device is opened exactly as before.
+
+/// The ray query feature.
+const RAY_QUERY: wgpu::Features = wgpu::Features::EXPERIMENTAL_RAY_QUERY;
+
+/// Whether the player asked for ray tracing (the device needs the feature from its creation).
+fn requested() -> bool {
+    asked(std::env::var("HORIZON_RAY_TRACING").ok().as_deref())
+}
+
+/// Whether `HORIZON_RAY_TRACING` set to `var` asks for ray tracing: only in a `horizon-extras`
+/// build.
+fn asked(var: Option<&str>) -> bool {
+    cfg!(feature = "horizon-extras") && var == Some("1")
+}
+
+/// The features to request on `adapter`: ray queries, when asked for and offered.
+pub(super) fn features(adapter: &wgpu::Adapter) -> wgpu::Features {
+    let features = pick(requested(), adapter.features());
+    if requested() {
+        let info = adapter.get_info();
+        if features.is_empty() {
+            log::warn!(
+                "Horizon renderer: ray tracing asked for, but {} on {:?} has no hardware ray \
+                 queries; it stays off",
+                info.name,
+                info.backend
+            );
+        } else {
+            log::info!(
+                "Horizon renderer: ray queries on ({} on {:?})",
+                info.name,
+                info.backend
+            );
+        }
+    }
+    features
+}
+
+fn pick(requested: bool, offered: wgpu::Features) -> wgpu::Features {
+    if requested {
+        offered & RAY_QUERY
+    } else {
+        wgpu::Features::empty()
+    }
+}
+
+/// The device's opt-in to `features`' experimental ones.
+pub(super) fn experimental(features: wgpu::Features) -> wgpu::ExperimentalFeatures {
+    if features.contains(RAY_QUERY) {
+        horizon_hdr::experimental_features()
+    } else {
+        wgpu::ExperimentalFeatures::disabled()
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    #[test]
+    fn only_an_extras_build_asks_for_ray_tracing() {
+        assert_eq!(asked(Some("1")), cfg!(feature = "horizon-extras"));
+        assert!(!asked(None));
+        assert!(!asked(Some("0")));
+    }
+
+    #[test]
+    fn ray_queries_only_when_asked_and_offered() {
+        let all = wgpu::Features::all();
+        assert_eq!(pick(true, all), RAY_QUERY);
+        assert!(pick(false, all).is_empty());
+        assert!(pick(true, all - RAY_QUERY).is_empty());
+        assert!(!experimental(wgpu::Features::empty()).is_enabled());
+    }
+}
@@ -0,0 +1,321 @@
+//! Writing a screenshot's PNG once its frame is read back: on the render thread for the
+//! requests that want the result with the frame (an agent's, a `screenshot-sequence`'s),
+//! on a thread of its own for F2's and the world icon's (`ScreenshotRequest::background`).
+//! The render thread then neither waits for the GPU to finish the frame nor encodes the
+//! PNG, which at 4K or a Screenshot Quality above 1x froze the game for a second or more.
+use super::{ScreenshotRequest, hdr_icc, hdr10_to_rgb16, padded_row, square_downscale};
+use std::path::PathBuf;
+use std::sync::mpsc::{Receiver, Sender, channel};
+use std::time::Duration;
+
+/// What a frame's readback holds and where its PNG goes.
+pub(super) struct Shot {
+    pub path: PathBuf,
+    /// `ScreenshotRequest::size`: the world icon's square.
+    pub size: Option<[u32; 2]>,
+    /// The frame's size, which the readback's rows hold (padded to `padded_row`).
+    pub frame: [u32; 2],
+    /// Blue first (`Bgra8Unorm`), swapped to PNG's red first.
+    pub bgra: bool,
+    /// The HDR10 copy's readback and its PNG's path, beside the SDR one.
+    pub hdr: Option<(PathBuf, wgpu::Buffer)>,
+}
+impl Shot {
+    pub fn new(
+        request: &ScreenshotRequest,
+        frame: [u32; 2],
+        format: wgpu::TextureFormat,
+        hdr: Option<(PathBuf, wgpu::Buffer)>,
+    ) -> Self {
+        Self {
+            path: request.path.clone(),
+            size: request.size,
+            frame,
+            bgra: format.remove_srgb_suffix() == wgpu::TextureFormat::Bgra8Unorm,
+            hdr,
+        }
+    }
+}
+/// A written screenshot: its path, its size or the error, and the HDR copy written beside it.
+pub struct Saved {
+    pub path: PathBuf,
+    pub result: Result<[u32; 2], String>,
+    pub hdr: Option<PathBuf>,
+}
+/// Waits for `buffer`'s mapping on the render thread and writes the PNG there.
+pub(super) fn save_now(device: &wgpu::Device, shot: Shot, buffer: &wgpu::Buffer) -> Saved {
+    let (sender, receiver) = channel();
+    map(buffer, &sender);
+    if let Some((_, hdr)) = &shot.hdr {
+        map(hdr, &sender);
+    }
+    let waited = device
+        .poll(wgpu::PollType::wait_indefinitely())
+        .map_err(|e| e.to_string());
+    let count = 1 + usize::from(shot.hdr.is_some());
+    let mapped = waited.and_then(|_| wait_mapped(&receiver, count));
+    write(shot, buffer, mapped)
+}
+/// Screenshots being written on their thread.
+pub(super) struct Saves {
+    device: wgpu::Device,
+    sender: Sender<Saved>,
+    receiver: Receiver<Saved>,
+    in_flight: usize,
+}
+impl Saves {
+    pub fn new(device: &wgpu::Device) -> Self {
+        let (sender, receiver) = channel();
+        Self {
+            device: device.clone(),
+            sender,
+            receiver,
+            in_flight: 0,
+        }
+    }
+    /// Maps `buffer` (and the HDR copy's), whose copy was just submitted, and writes the
+    /// PNG on a thread of its own once the GPU has finished the frame.
+    pub fn start(&mut self, shot: Shot, buffer: wgpu::Buffer) {
+        let (mapped, on_mapped) = channel();
+        map(&buffer, &mapped);
+        if let Some((_, hdr)) = &shot.hdr {
+            map(hdr, &mapped);
+        }
+        let done = self.sender.clone();
+        let path = shot.path.clone();
+        let spawned = std::thread::Builder::new()
+            .name("Screenshot writer".into())
+            .spawn(move || {
+                let count = 1 + usize::from(shot.hdr.is_some());
+                let ready = wait_mapped(&on_mapped, count);
+                let _ = done.send(write(shot, &buffer, ready));
+            });
+        match spawned {
+            Ok(_) => {}
+            Err(e) => {
+                let _ = self.sender.send(Saved {
+                    path,
+                    result: Err(format!("no thread to write it: {e}")),
+                    hdr: None,
+                });
+            }
+        }
+        self.in_flight += 1;
+    }
+    /// The screenshots written since the last call. Polls the device so a finished frame's
+    /// mapping reaches its writer: the render thread never waits for it.
+    pub fn finished(&mut self) -> Vec<Saved> {
+        if self.in_flight == 0 {
+            return Vec::new();
+        }
+        let _ = self.device.poll(wgpu::PollType::Poll);
+        let saved: Vec<Saved> = self.receiver.try_iter().collect();
+        self.in_flight -= saved.len();
+        saved
+    }
+}
+impl Drop for Saves {
+    /// A screenshot taken right before quitting is still written whole.
+    fn drop(&mut self) {
+        let deadline = std::time::Instant::now() + Duration::from_secs(10);
+        while self.in_flight > 0 && std::time::Instant::now() < deadline {
+            let _ = self.device.poll(wgpu::PollType::Poll);
+            if let Ok(saved) = self.receiver.recv_timeout(Duration::from_millis(20)) {
+                log_saved(&saved);
+                self.in_flight -= 1;
+            }
+        }
+    }
+}
+fn log_saved(saved: &Saved) {
+    match &saved.result {
+        Ok(_) => log::info!("Saved screenshot to {}", saved.path.display()),
+        Err(e) => log::warn!("Horizon renderer: screenshot {}: {e}", saved.path.display()),
+    }
+}
+fn map(buffer: &wgpu::Buffer, mapped: &Sender<Result<(), String>>) {
+    let mapped = mapped.clone();
+    buffer.map_async(wgpu::MapMode::Read, .., move |r| {
+        let _ = mapped.send(r.map_err(|e| e.to_string()));
+    });
+}
+/// `count` mappings done, or the first one that failed. A frame the GPU never finishes
+/// (a lost device) gives up after a while instead of keeping its thread.
+fn wait_mapped(mapped: &Receiver<Result<(), String>>, count: usize) -> Result<(), String> {
+    for _ in 0..count {
+        mapped
+            .recv_timeout(Duration::from_secs(30))
+            .map_err(|_| "the frame never came back from the GPU".to_string())??;
+    }
+    Ok(())
+}
+/// The PNG (and the HDR copy's beside it) from the mapped readbacks.
+fn write(shot: Shot, buffer: &wgpu::Buffer, mapped: Result<(), String>) -> Saved {
+    let mut hdr_written = None;
+    let result = mapped.and_then(|()| {
+        if let Some((hdr_path, hdr_buffer)) = &shot.hdr {
+            let pixels = read_rows(hdr_buffer, shot.frame);
+            match pixels.and_then(|p| write_hdr_png(hdr_path, shot.frame, &p)) {
+                Ok(()) => {
+                    log::info!("Saved HDR screenshot to {}", hdr_path.display());
+                    hdr_written = Some(hdr_path.clone());
+                }
+                Err(e) => log::warn!(
+                    "Horizon renderer: HDR screenshot {}: {e}",
+                    hdr_path.display()
+                ),
+            }
+        }
+        let pixels = read_rows(buffer, shot.frame)?;
+        write_png(&shot, &pixels)
+    });
+    Saved {
+        path: shot.path,
+        result,
+        hdr: hdr_written,
+    }
+}
+/// The pixels `copy_frame` read back into the mapped `buffer`, 4 bytes each, row after
+/// row; unmaps it.
+fn read_rows(buffer: &wgpu::Buffer, [width, height]: [u32; 2]) -> Result<Vec<[u8; 4]>, String> {
+    let (width, height, row) = (width as usize, height as usize, padded_row(width) as usize);
+    let mut pixels = Vec::with_capacity(width * height);
+    {
+        let data = buffer.get_mapped_range(..).map_err(|e| e.to_string())?;
+        for y in 0..height {
+            pixels.extend_from_slice(data[y * row..y * row + width * 4].as_chunks::<4>().0);
+        }
+    }
+    buffer.unmap();
+    Ok(pixels)
+}
+fn write_png(shot: &Shot, frame: &[[u8; 4]]) -> Result<[u32; 2], String> {
+    let [frame_w, frame_h] = shot.frame;
+    let mut pixels = Vec::with_capacity(frame.len() * 4);
+    for px in frame {
+        let (r, b) = if shot.bgra {
+            (px[2], px[0])
+        } else {
+            (px[0], px[2])
+        };
+        pixels.extend_from_slice(&[r, px[1], b, 255]);
+    }
+    // NativeImage.resizeSubRectTo on takeAutoScreenshot's grab: the icon
+    // is the frame's centre square averaged down to its size.
+    let (width, height, pixels) = match shot.size {
+        Some(size) => (
+            size[0],
+            size[1],
+            square_downscale(&pixels, frame_w, frame_h, size),
+        ),
+        None => (frame_w, frame_h, pixels),
+    };
+    let file = std::fs::File::create(&shot.path).map_err(|e| e.to_string())?;
+    let mut encoder = png::Encoder::new(std::io::BufWriter::new(file), width, height);
+    encoder.set_color(png::ColorType::Rgba);
+    encoder.set_depth(png::BitDepth::Eight);
+    encoder
+        .write_header()
+        .and_then(|mut w| w.write_image_data(&pixels))
+        .map_err(|e| e.to_string())?;
+    Ok([width, height])
+}
+/// The HDR10 copy (`Hdr::capture`) as a 16-bit PNG tagged BT.2020 with PQ (cICP, PNG's
+/// third edition), with the content light levels its pixels hold (cLLI), and
+/// an ICC profile for the programs that don't read cICP (`hdr_icc`).
+fn write_hdr_png(
+    path: &std::path::Path,
+    [width, height]: [u32; 2],
+    frame: &[[u8; 4]],
+) -> Result<(), String> {
+    let pixels = hdr10_to_rgb16(frame);
+    let mut info = png::Info::with_size(width, height);
+    info.color_type = png::ColorType::Rgb;
+    info.bit_depth = png::BitDepth::Sixteen;
+    info.icc_profile = Some(hdr_icc::profile().into());
+    let file = std::fs::File::create(path).map_err(|e| e.to_string())?;
+    let written = png::Encoder::with_info(std::io::BufWriter::new(file), info)
+        .and_then(|encoder| encoder.write_header())
+        .and_then(|mut writer| {
+            // BT.2020 primaries, PQ, RGB, full range.
+            writer.write_chunk(png::chunk::cICP, &[9, 16, 0, 1])?;
+            writer.write_chunk(png::chunk::cLLI, &hdr_icc::content_light_levels(&pixels))?;
+            writer.write_image_data(&pixels)
+        });
+    written.map_err(|e| e.to_string())
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    #[test]
+    fn a_background_save_writes_the_png_off_the_render_thread() {
+        let instance = crate::gfx::test_gpu::instance();
+        let Ok(adapter) = pollster::block_on(instance.request_adapter(&Default::default())) else {
+            return;
+        };
+        let Ok((device, queue)) = pollster::block_on(adapter.request_device(&Default::default()))
+        else {
+            return;
+        };
+        let dir = std::env::temp_dir().join(format!("horizon-shot-{}", std::process::id()));
+        std::fs::create_dir_all(&dir).unwrap();
+        let path = dir.join("shot.png");
+        let [w, h] = [3u32, 2];
+        // A frame of blue-first pixels, each row padded as `copy_frame` reads them back.
+        let row = padded_row(w) as usize;
+        let mut bytes = vec![0u8; row * h as usize];
+        for y in 0..h as usize {
+            for x in 0..w as usize {
+                bytes[y * row + x * 4..][..4].copy_from_slice(&[10 * x as u8, 20, 200, 0]);
+            }
+        }
+        let source = wgpu::util::DeviceExt::create_buffer_init(
+            &device,
+            &wgpu::util::BufferInitDescriptor {
+                label: None,
+                contents: &bytes,
+                usage: wgpu::BufferUsages::COPY_SRC,
+            },
+        );
+        let buffer = device.create_buffer(&wgpu::BufferDescriptor {
+            label: None,
+            size: bytes.len() as u64,
+            usage: wgpu::BufferUsages::COPY_DST | wgpu::BufferUsages::MAP_READ,
+            mapped_at_creation: false,
+        });
+        let mut encoder = device.create_command_encoder(&Default::default());
+        encoder.copy_buffer_to_buffer(&source, 0, &buffer, 0, bytes.len() as u64);
+        queue.submit([encoder.finish()]);
+        let request = ScreenshotRequest {
+            path: path.clone(),
+            size: None,
+            scaled: false,
+            background: true,
+        };
+        let mut saves = Saves::new(&device);
+        saves.start(
+            Shot::new(&request, [w, h], wgpu::TextureFormat::Bgra8Unorm, None),
+            buffer,
+        );
+        let deadline = std::time::Instant::now() + Duration::from_secs(10);
+        let saved = loop {
+            if let Some(saved) = saves.finished().pop() {
+                break saved;
+            }
+            assert!(std::time::Instant::now() < deadline, "never written");
+            std::thread::sleep(Duration::from_millis(5));
+        };
+        assert_eq!(saved.path, path);
+        assert_eq!(saved.result, Ok([w, h]));
+        let decoder =
+            png::Decoder::new(std::io::BufReader::new(std::fs::File::open(&path).unwrap()));
+        let mut reader = decoder.read_info().unwrap();
+        let mut out = vec![0; reader.output_buffer_size().unwrap()];
+        reader.next_frame(&mut out).unwrap();
+        // Red first, opaque: the last pixel of the first row was [20, 20, 200] blue-first.
+        assert_eq!(&out[8..12], &[200, 20, 20, 255]);
+        std::fs::remove_dir_all(&dir).unwrap();
+    }
+}
@@ -5,6 +5,9 @@ use super::{
    Renderer, check_layers, cull, describe_adapter, is_software, oit, startup_step, surface_format,
    timing,
 };
+// Ray tracing on request, which the device needs from its creation (gfx.rs may not grow).
+#[path = "ray_query.rs"]
+mod ray_query;
 use std::sync::Arc;
 use winit::window::Window;

@@ -134,6 +137,7 @@ pub(super) async fn open_adapter(
    let features = timing::GpuTimer::features(adapter)
        | cull::Cull::features(adapter)
        | oit::features(adapter)
+        | ray_query::features(adapter)
        | (adapter.features()
            & (wgpu::Features::INDIRECT_FIRST_INSTANCE
                | wgpu::Features::MULTI_DRAW_INDIRECT_COUNT
@@ -166,6 +170,7 @@ pub(super) async fn open_adapter(
        // with the larger blocks a few small buffers kept whole blocks the arena's pages had
        // left, and over half the video memory reserved was unused (1,344 MiB for 500).
        memory_hints: wgpu::MemoryHints::MemoryUsage,
+        experimental_features: ray_query::experimental(features),
        ..Default::default()
    };
    #[cfg(not(target_os = "macos"))]
@@ -30,6 +30,22 @@ fn marker_driver(text: &str) -> &str {
 pub struct Reported {
    pub paper_white: u32,
    pub peak: u32,
+    /// The peak is the display's own claim (DXGI's `MaxLuminance`, mostly its EDID figure),
+    /// which often runs high: Auto still uses it, but the HDR page asks to calibrate.
+    pub peak_guessed: bool,
+}
+
+/// Whether HDR is set up for the display, and whether the player kept the system's setup.
+#[derive(Clone, Copy, Debug, PartialEq, Eq)]
+pub enum HdrSetup {
+    /// The system says nothing: the player calibrates.
+    Unknown,
+    /// The system says, but only guesses the peak: the player calibrates.
+    Guessed,
+    /// Peak Brightness and Paper White follow the system.
+    Automatic,
+    /// The system said, and the player changed them anyway.
+    Changed,
 }

 /// The top of Peak Brightness's scale: `peak_nits_at(PEAK_STEPS)` is PQ's 10 000 nits.
@@ -1207,6 +1223,15 @@ impl Graphics {
            n => n,
        }
    }
+    /// How HDR is set up for the display the system `reported`.
+    pub fn hdr_setup(&self, reported: Option<Reported>) -> HdrSetup {
+        match reported {
+            None => HdrSetup::Unknown,
+            Some(_) if self.hdr_peak != 0 || self.hdr_paper_white != 0 => HdrSetup::Changed,
+            Some(r) if r.peak_guessed => HdrSetup::Guessed,
+            Some(_) => HdrSetup::Automatic,
+        }
+    }
    /// The black level, in nits. Not the system's: files from before saved 0 for that
    /// (Auto), and a reported black would lift every display's shadows by default.
    pub fn black_level_nits(&self) -> f32 {
@@ -1320,6 +1345,7 @@ mod tests {
        let reported = Some(Reported {
            paper_white: 300,
            peak: 1000,
+            peak_guessed: false,
        });
        assert_eq!(g.ui_nits(reported), 300);
        g.hdr_paper_white = 120;
@@ -1328,6 +1354,33 @@ mod tests {
        assert_eq!((g.ui_nits(None), g.ui_nits(reported)), (400, 400));
    }

+    #[test]
+    fn hdr_setup_asks_to_calibrate_where_the_peak_is_guessed() {
+        let wayland = Reported {
+            paper_white: 203,
+            peak: 1015,
+            peak_guessed: false,
+        };
+        let windows = Reported {
+            paper_white: 400,
+            peak: 1000,
+            peak_guessed: true,
+        };
+        let mut g = Graphics::default();
+        assert_eq!(g.hdr_setup(None), HdrSetup::Unknown);
+        assert_eq!(g.hdr_setup(Some(wayland)), HdrSetup::Automatic);
+        assert_eq!(g.hdr_setup(Some(windows)), HdrSetup::Guessed);
+        // Auto still takes the guess, over the 1000-nit default.
+        assert_eq!(g.peak_nits(Some(windows)), 1000);
+        assert_eq!(g.paper_white_nits(Some(windows)), 400);
+        for (peak, paper_white) in [(800, 0), (0, 240)] {
+            (g.hdr_peak, g.hdr_paper_white) = (peak, paper_white);
+            assert_eq!(g.hdr_setup(Some(windows)), HdrSetup::Changed);
+            assert_eq!(g.hdr_setup(Some(wayland)), HdrSetup::Changed);
+            assert_eq!(g.hdr_setup(None), HdrSetup::Unknown);
+        }
+    }
+
    #[test]
    fn hdr_modes_keep_boolean_files_and_round_trip_auto() {
        assert_eq!(Graphics::parse("").hdr, HdrMode::Off);
@@ -2,16 +2,21 @@
 //! colours and the controls it draws with. The screen (`graphics_ui`) only
 //! lays out rows and handles input; a menu theme replaces this module.
 //!
-//! It takes the design system's Blocks palette (`horizon_theme::BLOCKS_DARK`,
-//! `docs/design-system.md`) in a lighter form: square panels of dark glass
-//! with a thin edge, so the world shows through, flat controls, and the violet
-//! face on the one main button, in vanilla's font.
+//! Its colours come from `menu_style`, given at startup (in the official game the design
+//! system's Blocks palette, `docs/design-system.md`), in a lighter form: square panels of
+//! dark glass with a thin edge, so the world shows through, flat controls, and the face on
+//! the one main button, in vanilla's font.
+use crate::menu_style::{self, SettingsColours};
 use crate::{
    hud::{HudAtlas, HudBatch},
    text::Text,
    ui,
 };
-use horizon_theme::BLOCKS_DARK as B;
+
+/// The settings pages' colours (`menu_style`, given at startup).
+fn b() -> &'static SettingsColours {
+    &menu_style::get().settings
+}

 /// What a setting costs in frame time, shown with its description.
 #[derive(Clone, Copy, Debug, PartialEq, Eq)]
@@ -36,54 +41,91 @@ impl Cost {
    /// `0xRRGGBB`: the palette's success, warn and danger.
    pub fn rgb(self) -> u32 {
        match self {
-            Cost::None => B.ink_soft,
-            Cost::Low | Cost::Saves => B.success,
-            Cost::Medium => B.warn,
-            Cost::High => B.danger,
+            Cost::None => b().ink_soft,
+            Cost::Low | Cost::Saves => b().success,
+            Cost::Medium => b().warn,
+            Cost::High => b().danger,
        }
    }
 }

-/// `0xRRGGBB` and an alpha in the HUD's colour encoding.
-const fn hex(c: u32, a: u8) -> u32 {
-    (a as u32) << 24 | (c & 0xff) << 16 | (c >> 8 & 0xff) << 8 | (c >> 16 & 0xff)
-}
+use menu_style::hud_colour as hex;
 /// The plate and the strip: the page's dark, see-through, so the world shows behind them.
-const GLASS: u32 = hex(B.page, 118);
+fn glass() -> u32 {
+    hex(b().page, 118)
+}
 /// Their 1 px edge.
-const EDGE: u32 = hex(B.ink, 26);
+pub fn edge() -> u32 {
+    hex(b().ink, 26)
+}
 /// A group's panel, a little lighter than the plate it sits on.
-const GROUP: u32 = hex(B.ink, 11);
+fn group_fill() -> u32 {
+    hex(b().ink, 11)
+}
 /// A hovered or focused row, lit on its group's panel.
-pub const HOVER: u32 = hex(B.ink, 18);
+pub fn hover() -> u32 {
+    hex(b().ink, 18)
+}
 /// The open page in the page list.
-pub const OPEN: u32 = hex(B.ink, 26);
+pub fn open() -> u32 {
+    hex(b().ink, 26)
+}
 /// The rule under the plate's heading, and between two rows of a group.
-pub const HEAD_RULE: u32 = hex(B.ink, 31);
-pub const ROW_RULE: u32 = hex(B.ink, 15);
+pub fn head_rule() -> u32 {
+    hex(b().ink, 31)
+}
+pub fn row_rule() -> u32 {
+    hex(b().ink, 15)
+}
 /// Fields, boxes and the value stepper: sunk, see-through.
-const WELL: u32 = hex(B.outline, 102);
+fn well_fill() -> u32 {
+    hex(b().outline, 102)
+}
 /// A button, a slider's track, the scroller's thumb.
-const BUTTON: u32 = hex(B.ink, 20);
-const BUTTON_HOVER: u32 = hex(B.ink, 41);
-const TRACK: u32 = hex(B.ink, 64);
-const HANDLE: u32 = hex(B.ink, 255);
+fn button_fill() -> u32 {
+    hex(b().ink, 20)
+}
+fn button_hover() -> u32 {
+    hex(b().ink, 41)
+}
+fn track_fill() -> u32 {
+    hex(b().ink, 64)
+}
+fn handle_fill() -> u32 {
+    hex(b().ink, 255)
+}
 /// The one main button.
-const FACE: u32 = hex(B.face, 255);
-const FACE_HOVER: u32 = hex(0x6a50e6, 255);
+pub fn face() -> u32 {
+    hex(b().face, 255)
+}
+fn face_hover() -> u32 {
+    hex(b().face_hover, 255)
+}
 /// A tick box's edge when off.
-const BOX_EDGE: u32 = hex(B.ink_soft, 89);
-const OUTLINE: u32 = hex(B.outline, 255);
-pub const ACCENT: u32 = hex(B.accent, 255);
+fn box_edge() -> u32 {
+    hex(b().ink_soft, 89)
+}
+fn outline() -> u32 {
+    hex(b().outline, 255)
+}
+pub fn accent() -> u32 {
+    hex(b().accent, 255)
+}
 /// Vanilla's white text, and its grey for what can't be used now.
 pub const WHITE: u32 = u32::MAX;
-pub const MUTED: u32 = hex(B.muted, 255);
+pub fn muted() -> u32 {
+    hex(b().muted, 255)
+}
 /// A page that isn't open, a value at rest.
-pub const SOFT: u32 = hex(B.ink_soft, 255);
+pub fn soft() -> u32 {
+    hex(b().ink_soft, 255)
+}
 /// Vanilla's grey for a tooltip's lines under its first (`ChatFormatting.GRAY`).
 pub const GREY: u32 = hex(0xaaaaaa, 255);
 /// A light veil over the backdrop, under the panels.
-pub const VEIL: u32 = hex(B.page, 77);
+pub fn veil() -> u32 {
+    hex(b().page, 77)
+}

 /// Sizes in GUI pixels.
 /// Shorter screens than this (a 720p window at scale 3) keep a narrower margin on top.
@@ -120,21 +162,21 @@ pub fn ring(batch: &mut HudBatch, atlas: &HudAtlas, [x, y, w, h]: [f32; 4], colo
 }
 /// The screen's plate, and the strip under it: dark glass with a thin edge.
 pub fn panel(batch: &mut HudBatch, atlas: &HudAtlas, rect: [f32; 4]) {
-    fill(batch, atlas, rect, GLASS);
-    ring(batch, atlas, rect, EDGE);
+    fill(batch, atlas, rect, glass());
+    ring(batch, atlas, rect, edge());
 }
 /// A group's panel on the plate, its rows on it.
 pub fn group(batch: &mut HudBatch, atlas: &HudAtlas, rect: [f32; 4]) {
-    fill(batch, atlas, rect, GROUP);
+    fill(batch, atlas, rect, group_fill());
 }
 /// A sunk well: the search field, the value stepper.
 pub fn well(batch: &mut HudBatch, atlas: &HudAtlas, rect: [f32; 4]) {
-    fill(batch, atlas, rect, WELL);
+    fill(batch, atlas, rect, well_fill());
 }
 /// The scroller: a faint track and its thumb.
 pub fn scroller(batch: &mut HudBatch, atlas: &HudAtlas, track: [f32; 4], thumb: [f32; 4]) {
-    fill(batch, atlas, track, ROW_RULE);
-    fill(batch, atlas, thumb, TRACK);
+    fill(batch, atlas, track, row_rule());
+    fill(batch, atlas, thumb, track_fill());
 }
 /// `text` cut to `width` with an ellipsis, as a long name gives way to its control: the HUD
 /// kit's `fit::ellipsize`.
@@ -142,11 +184,11 @@ pub use crate::hud_kit::fit::ellipsize as fit;
 /// A 12 px tick box ending at `right`, centred in the row at `y`: its edge in the accent when on.
 pub fn checkbox(batch: &mut HudBatch, atlas: &HudAtlas, right: f32, y: f32, on: bool, live: bool) {
    let rect = [right - 12.0, y + 4.0, 12.0, 12.0];
-    fill(batch, atlas, rect, WELL);
+    fill(batch, atlas, rect, well_fill());
    let edge = match (on, live) {
-        (true, true) => ACCENT,
-        (true, false) => MUTED,
-        (false, _) => BOX_EDGE,
+        (true, true) => accent(),
+        (true, false) => muted(),
+        (false, _) => box_edge(),
    };
    ring(batch, atlas, rect, edge);
    if on {
@@ -169,7 +211,7 @@ fn tick(batch: &mut HudBatch, atlas: &HudAtlas, x: f32, y: f32, color: u32) {
        for (i, c) in row.chars().enumerate() {
            if c == '#' {
                let (px, py) = (x + i as f32, y + j as f32);
-                fill(batch, atlas, [px + 1.0, py + 1.0, 1.0, 1.0], OUTLINE);
+                fill(batch, atlas, [px + 1.0, py + 1.0, 1.0, 1.0], outline());
                fill(batch, atlas, [px, py, 1.0, 1.0], color);
            }
        }
@@ -198,17 +240,17 @@ pub fn button_with_room(
 ) {
    let [x, y, w, h] = rect;
    let face = match (live, primary, hover) {
-        (false, _, _) => WELL,
-        (true, true, false) => FACE,
-        (true, true, true) => FACE_HOVER,
-        (true, false, false) => BUTTON,
-        (true, false, true) => BUTTON_HOVER,
+        (false, _, _) => well_fill(),
+        (true, true, false) => face(),
+        (true, true, true) => face_hover(),
+        (true, false, false) => button_fill(),
+        (true, false, true) => button_hover(),
    };
    fill(batch, atlas, rect, face);
    if hover && live {
        ring(batch, atlas, rect, WHITE);
    }
-    let color = if live { WHITE } else { MUTED };
+    let color = if live { WHITE } else { muted() };
    let ty = y + ((h - 8.0) / 2.0).floor();
    let left = x + 2.0 + room;
    scrolling_label(
@@ -252,7 +294,7 @@ pub fn slider(
    (hover, live): (bool, bool),
 ) {
    let [x, y, w, h] = rect;
-    let color = if live { WHITE } else { MUTED };
+    let color = if live { WHITE } else { muted() };
    scrolling_label(
        batch,
        atlas,
@@ -263,17 +305,22 @@ pub fn slider(
    );
    let line = y + h - 3.0;
    let at = x + (position.clamp(0.0, 1.0) * (w - 4.0)).round();
-    fill(batch, atlas, [x, line, w, 2.0], TRACK);
+    fill(batch, atlas, [x, line, w, 2.0], track_fill());
    fill(
        batch,
        atlas,
        [x, line, at - x, 2.0],
-        if live { ACCENT } else { MUTED },
+        if live { accent() } else { muted() },
    );
    let handle = [at, line - 3.0, 4.0, 8.0];
-    fill(batch, atlas, handle, if live { HANDLE } else { MUTED });
+    fill(
+        batch,
+        atlas,
+        handle,
+        if live { handle_fill() } else { muted() },
+    );
    if hover && live {
-        ring(batch, atlas, [at - 1.0, line - 4.0, 6.0, 10.0], ACCENT);
+        ring(batch, atlas, [at - 1.0, line - 4.0, 6.0, 10.0], accent());
    }
 }
 /// A value that a press steps through: in a well, between the arrows that say so.
@@ -290,13 +337,13 @@ pub fn cycler(
        ring(batch, atlas, rect, WHITE);
    }
    let ty = y + ((h - 8.0) / 2.0).floor();
-    let arrows = if hover && live { WHITE } else { MUTED };
+    let arrows = if hover && live { WHITE } else { muted() };
    batch.text_styled(atlas, &Text::literal("<"), x + 3.0, ty, arrows, true);
    batch.text_styled(atlas, &Text::literal(">"), x + w - 8.0, ty, arrows, true);
    let color = match (live, hover) {
-        (false, _) => MUTED,
+        (false, _) => muted(),
        (true, true) => WHITE,
-        (true, false) => SOFT,
+        (true, false) => soft(),
    };
    scrolling_label(batch, atlas, value, [x + 9.0, ty, w - 18.0], (y, h), color);
 }
@@ -8,7 +8,8 @@ use crate::{
    gfx::EffectiveOutput,
    graphics::{
        EntityCullingMode, FarDetail, FrameGeneration, GpuCullingMode, GraphicsApi, HdrMode,
-        LeafCullingMode, Overlay, Pacing, ParticleCullingMode, PresentMode, Preset, Upscaling,
+        HdrSetup as Setup, LeafCullingMode, Overlay, Pacing, ParticleCullingMode, PresentMode,
+        Preset, Upscaling,
    },
    graphics_style::Cost,
    lang,
@@ -675,28 +676,9 @@ const LOD_STEPS: [u32; 24] = [
    crate::lod::MAX_CHUNKS,
 ];

-/// Whether the system set HDR up for the display, and whether the player kept it.
-#[derive(Clone, Copy, Debug, PartialEq, Eq)]
-enum Setup {
-    /// The system says nothing: the player calibrates.
-    Unknown,
-    /// Peak Brightness and Paper White follow the system.
-    Automatic,
-    /// The system said, and the player changed them anyway.
-    Changed,
-}
 /// `out`: the output of the renderer the settings are shown for, with what its display reports.
 fn setup(s: &Settings, out: &EffectiveOutput) -> Setup {
-    setup_of(&s.horizon, out.reported.is_some())
-}
-fn setup_of(g: &crate::graphics::Graphics, reported: bool) -> Setup {
-    if !reported {
-        Setup::Unknown
-    } else if g.hdr_peak == 0 && g.hdr_paper_white == 0 {
-        Setup::Automatic
-    } else {
-        Setup::Changed
-    }
+    s.horizon.hdr_setup(out.reported)
 }
 /// What the HDR page says while HDR output is held back on this window's graphics driver
 /// (`EffectiveOutput::held`): picking a mode tries again (`H::cycle`).
@@ -714,13 +696,19 @@ fn description(
        (Item::Horizon(H::HdrCalibrate), Setup::Unknown) => {
            "Your display didn't say how bright it gets: calibrate to set it up."
        }
+        (Item::Horizon(H::HdrCalibrate), Setup::Guessed) => {
+            "Your display's reported peak is often too high: calibrate to set it up."
+        }
        (Item::Horizon(H::HdrCalibrate), Setup::Automatic) => {
            "Already set up for your display. Only calibrate if HDR looks wrong."
        }
        (Item::Horizon(H::HdrCalibrate), Setup::Changed) => {
            "Puts Peak Brightness and Paper White back to your display's setup."
        }
-        (Item::Horizon(H::HdrPeak | H::HdrPaperWhite), Setup::Automatic | Setup::Changed) => {
+        // A guessed peak's Auto is what calibration replaced; paper white is the player's own.
+        (Item::Horizon(h @ (H::HdrPeak | H::HdrPaperWhite)), Setup::Automatic | Setup::Changed)
+            if h == H::HdrPaperWhite || out.reported.is_some_and(|r| !r.peak_guessed) =>
+        {
            "Set up for your display. Leave on Auto unless it looks wrong."
        }
        (Item::Horizon(H::GpuCulling), _) if s.horizon.gpu_culling == GpuCullingMode::Auto => {
@@ -944,7 +932,7 @@ impl H {
            H::FrameGeneration => labelled("Frame Generation", g.frame_generation.label()),
            H::Hdr => labelled("HDR", g.hdr.label()),
            H::HdrCalibrate => Text::literal(lang::get(match setup(s, out) {
-                Setup::Unknown => "Calibrate...",
+                Setup::Unknown | Setup::Guessed => "Calibrate...",
                Setup::Automatic => "Calibrate Anyway...",
                Setup::Changed => "Use Automatic Setup",
            })),
@@ -1122,7 +1110,8 @@ impl Item {
    /// active; saved values wait for it. Translucent Batching switches where the device can batch
    /// (`graphics::translucent_batching_offered`), its saved value waiting for one that can,
    /// Smooth Gradients only where it can draw the 16-bit frame, the same way, and GPU Culling
-    /// only where it is offered (`graphics::gpu_culling_offer`), with the reason it isn't.
+    /// only where it is offered (`graphics::gpu_culling_offer`), with the reason it isn't. HDR
+    /// Lighting has nothing to switch where the running shader pack lights the world itself.
    fn blocked(self, s: &Settings, out: &EffectiveOutput) -> Option<&'static str> {
        if !self.available() {
            return Some("This feature is not yet available in Horizon.");
@@ -1153,6 +1142,9 @@ impl Item {
            } else {
                "Turn HDR on to use it."
            }),
+            Item::Horizon(H::HdrLighting) if out.pack_lights => {
+                Some("The shader pack lights the world itself.")
+            }
            Item::Horizon(H::TranslucentBatching)
                if !crate::graphics::translucent_batching_offered() =>
            {
@@ -31,6 +31,49 @@ fn smooth_gradients_wait_for_a_device_that_draws_the_16_bit_frame() {
    assert_eq!(item.blocked(&s, &out), Some("Turn HDR on to use it."));
 }

+#[test]
+fn hdr_lighting_is_greyed_only_where_the_running_pack_lights_the_world() {
+    use horizon_shader_api::Api;
+    let mut s = Settings::default();
+    s.horizon.hdr = HdrMode::On;
+    let item = Item::Horizon(H::HdrLighting);
+    let lights = Some("The shader pack lights the world itself.");
+    let out = offering(true, None);
+    // No pack running, as with one picked but refused, missing or its mod off: live.
+    assert_eq!(item.blocked(&s, &out.with_pack(false, None)), None);
+    // A 0.1 pack on the 16-bit frame: the light sources and the sun still shine.
+    assert_eq!(
+        item.blocked(&s, &out.with_pack(false, Some(Api::V0_1))),
+        None
+    );
+    assert_eq!(
+        item.blocked(&s, &out.with_pack(false, Some(Api::V0_2))),
+        lights
+    );
+    assert_eq!(item.blocked(&s, &out.with_pack(true, None)), lights);
+    let float = EffectiveOutput {
+        frame: crate::gfx::FrameConfiguration {
+            format: wgpu::TextureFormat::Rgba16Float,
+            ..out.frame
+        },
+        ..out
+    };
+    assert_eq!(
+        item.blocked(&s, &float.with_pack(false, Some(Api::V0_1))),
+        lights
+    );
+    // HDR's own reasons come first.
+    assert_eq!(
+        item.blocked(&s, &NONE.with_pack(true, None)),
+        Some("Your display or system doesn't offer HDR output.")
+    );
+    s.horizon.hdr = HdrMode::Off;
+    assert_eq!(
+        item.blocked(&s, &out.with_pack(true, None)),
+        Some("Turn HDR on to use it.")
+    );
+}
+
 #[test]
 fn hdr_auto_can_be_selected_before_querying_and_brightness_waits_for_output() {
    let mut s = Settings::default();
@@ -120,14 +163,86 @@ fn auto_levels_and_setup_read_their_own_renderers_report() {
    assert_eq!(label(H::HdrCalibrate, &silent), "Calibrate...");
 }

+/// The setup rows' label and description for each kind of report: none, a compositor's
+/// (Wayland), and Windows', whose peak is the display's own guess.
 #[test]
-fn hdr_setup_follows_what_the_system_reported() {
-    let mut g = crate::graphics::Graphics::default();
-    assert_eq!(setup_of(&g, false), Setup::Unknown);
-    assert_eq!(setup_of(&g, true), Setup::Automatic);
-    g.hdr_paper_white = 80;
-    assert_eq!(setup_of(&g, true), Setup::Changed);
-    assert_eq!(setup_of(&g, false), Setup::Unknown);
+fn the_setup_rows_ask_to_calibrate_unless_the_system_set_the_display_up() {
+    let trusted = offering(true, Some(true));
+    let mut guessed = trusted;
+    guessed.reported = guessed.reported.map(|r| crate::graphics::Reported {
+        peak_guessed: true,
+        ..r
+    });
+    let rows = |s: &Settings, out: &EffectiveOutput| {
+        [H::HdrCalibrate, H::HdrPeak, H::HdrPaperWhite].map(|h| {
+            let item = Item::Horizon(h);
+            (item.label(s, out).plain(), description(item, s, out, "-"))
+        })
+    };
+    let calibrate = "Calibrate...";
+    let set_up = "Set up for your display. Leave on Auto unless it looks wrong.";
+    let mut s = Settings::default();
+    s.horizon.hdr = HdrMode::On;
+    let none = (
+        calibrate.into(),
+        "Your display didn't say how bright it gets: calibrate to set it up.",
+    );
+    assert_eq!(
+        rows(&s, &NONE),
+        [
+            none.clone(),
+            ("Peak Brightness: Auto (1000)".into(), "-"),
+            ("Paper White: Auto (203)".into(), "-"),
+        ]
+    );
+    assert_eq!(
+        rows(&s, &guessed),
+        [
+            (
+                calibrate.into(),
+                "Your display's reported peak is often too high: calibrate to set it up."
+            ),
+            ("Peak Brightness: Auto (1000)".into(), "-"),
+            ("Paper White: Auto (400)".into(), "-"),
+        ]
+    );
+    assert_eq!(
+        rows(&s, &trusted),
+        [
+            (
+                "Calibrate Anyway...".into(),
+                "Already set up for your display. Only calibrate if HDR looks wrong."
+            ),
+            ("Peak Brightness: Auto (1000)".into(), set_up),
+            ("Paper White: Auto (400)".into(), set_up),
+        ]
+    );
+    // Calibrated or set by hand, either report offers its automatic setup back.
+    s.horizon.hdr_peak = 800;
+    // Peak's Auto stays a guess on Windows: only Paper White is said to be set up there.
+    let changed = |peak| {
+        [
+            (
+                "Use Automatic Setup".into(),
+                "Puts Peak Brightness and Paper White back to your display's setup.",
+            ),
+            ("Peak Brightness: 800".into(), peak),
+            ("Paper White: Auto (400)".into(), set_up),
+        ]
+    };
+    assert_eq!(rows(&s, &guessed), changed("-"));
+    assert_eq!(rows(&s, &trusted), changed(set_up));
+    assert_eq!(rows(&s, &NONE)[0], none);
+    let mut ui = ui();
+    ui.screen.output = guessed;
+    let at = |[x, y, ..]: [f32; 4]| (x + 8.0, y + 4.0);
+    let calibrate = row(&mut ui, &s, Item::Horizon(H::HdrCalibrate));
+    assert_eq!(press(&mut ui, &mut s, at(calibrate)), [CLICK, CHANGED]);
+    assert_eq!((s.horizon.hdr_peak, s.horizon.hdr_paper_white), (0, 0));
+    assert_eq!(
+        press(&mut ui, &mut s, at(calibrate)),
+        [CLICK, Output::Push(OptionsPage::HdrCalibration)]
+    );
 }

 /// UI Brightness reads as Paper White does, in nits apart from it: Auto shows the paper white
@@ -3,8 +3,9 @@
 //! where a tween is at the frame's [`Clock`]; nothing here holds state or runs on its own, and
 //! no motion ever decides what input does.
 //!
-//! The curves are the design system's (`horizon_theme::QUICK`, `MOVE`): a [`Tween`] takes one
-//! of them, at the theme's duration or a shorter one of its own.
+//! A [`Tween`] takes a duration and a CSS `cubic-bezier` curve: Horizon's overlays use the design
+//! system's (`horizon_theme::QUICK`, `MOVE`), at the theme's duration or a shorter one of their
+//! own.
 //!
 //! The game builds the clock once a frame (`Clock::new(now, still)`). A still clock (the game is
 //! paused, frame-stepped by `HORIZON_STILL` or a screenshot sequence, or a repro recording or
@@ -16,7 +17,7 @@
 //! use std::time::{Duration, Instant};
 //!
 //! let opened = Instant::now();
-//! let open = Tween::new(Duration::from_millis(90), horizon_theme::QUICK);
+//! let open = Tween::new(Duration::from_millis(90), [0.4, 0.0, 0.2, 1.0]);
 //! // Half way through: partly faded in, partly grown from 94%.
 //! let clock = Clock::new(opened + Duration::from_millis(45), false);
 //! let alpha = motion::fade(open, clock, opened);
@@ -26,7 +27,6 @@
 //! let still = Clock::new(opened, true);
 //! assert_eq!(motion::fade(open, still, opened), 1.0);
 //! ```
-use horizon_theme::Motion;
 use std::time::{Duration, Instant};

 /// The time a frame shows, built once a frame by the game.
@@ -50,28 +50,20 @@ impl Clock {
    }
 }

-/// A duration and one of the design system's easing curves.
+/// A duration and an easing curve.
 #[derive(Clone, Copy, Debug, PartialEq)]
 pub struct Tween {
    /// How long it runs.
    pub duration: Duration,
-    /// The CSS `cubic-bezier` control points of its curve (a `horizon_theme::Motion`'s).
+    /// The CSS `cubic-bezier` control points of its curve.
    pub curve: [f32; 4],
 }

 impl Tween {
-    /// `motion`'s curve over `duration`: the dial's motions are shorter than the launcher's, on
-    /// the same curves.
-    pub const fn new(duration: Duration, motion: Motion) -> Self {
-        Self {
-            duration,
-            curve: motion.curve,
-        }
-    }
-
-    /// A theme motion as it is: its own duration and curve.
-    pub const fn of(motion: Motion) -> Self {
-        Self::new(motion.duration(), motion)
+    /// `curve` over `duration`: the dial's motions are shorter than the launcher's, on the same
+    /// curves.
+    pub const fn new(duration: Duration, curve: [f32; 4]) -> Self {
+        Self { duration, curve }
    }

    /// The linear progress, 0 to 1, `since` a start at this clock; 1 on a still clock.
@@ -84,7 +76,7 @@ impl Tween {

    /// The eased progress, 0 to 1, on the tween's curve.
    pub fn progress(self, clock: Clock, since: Instant) -> f32 {
-        horizon_theme::bezier(self.curve, self.linear(clock, since))
+        bezier(self.curve, self.linear(clock, since))
    }

    /// Whether it has finished (always, on a still clock).
@@ -98,6 +90,29 @@ impl Tween {
    }
 }

+/// A CSS `cubic-bezier(x1, y1, x2, y2)` at `t` in 0..1: solves x for the curve parameter,
+/// returns y.
+pub fn bezier([x1, y1, x2, y2]: [f32; 4], t: f32) -> f32 {
+    let t = t.clamp(0.0, 1.0);
+    if t == 0.0 || t == 1.0 {
+        return t;
+    }
+    let at = |a: f32, b: f32, s: f32| {
+        let u = 1.0 - s;
+        3.0 * u * u * s * a + 3.0 * u * s * s * b + s * s * s
+    };
+    let (mut lo, mut hi) = (0f32, 1f32);
+    for _ in 0..24 {
+        let mid = (lo + hi) / 2.0;
+        if at(x1, x2, mid) < t {
+            lo = mid;
+        } else {
+            hi = mid;
+        }
+    }
+    at(y1, y2, (lo + hi) / 2.0)
+}
+
 /// An alpha from 0 to 1 as something fades in.
 pub fn fade(tween: Tween, clock: Clock, since: Instant) -> f32 {
    tween.progress(clock, since)
@@ -145,7 +160,7 @@ mod tests {
    #[test]
    fn a_tween_runs_from_its_start_to_its_end_and_holds() {
        let t0 = Instant::now();
-        let tween = Tween::new(MS(80), horizon_theme::MOVE);
+        let tween = Tween::new(MS(80), horizon_theme::MOVE.curve);
        assert_eq!(tween.progress(at(t0, 0), t0), 0.0);
        assert_eq!(tween.progress(at(t0, 80), t0), 1.0);
        assert_eq!(tween.progress(at(t0, 500), t0), 1.0);
@@ -160,8 +175,7 @@ mod tests {
    fn a_still_clock_shows_every_motion_settled() {
        let t0 = Instant::now();
        let still = Clock::new(t0, true);
-        let tween = Tween::of(horizon_theme::QUICK);
-        assert_eq!(tween.duration, horizon_theme::QUICK.duration());
+        let tween = Tween::new(horizon_theme::QUICK.duration(), horizon_theme::QUICK.curve);
        assert_eq!(fade(tween, still, t0), 1.0);
        assert_eq!(fade_out(tween, still, t0), 0.0);
        assert_eq!(scale_in(tween, still, t0, 0.94), 1.0);
@@ -173,7 +187,7 @@ mod tests {
    #[test]
    fn the_helpers_start_where_they_say() {
        let t0 = Instant::now();
-        let tween = Tween::new(MS(100), horizon_theme::QUICK);
+        let tween = Tween::new(MS(100), horizon_theme::QUICK.curve);
        let c = at(t0, 0);
        assert_eq!(fade(tween, c, t0), 0.0);
        assert_eq!(fade_out(tween, c, t0), 1.0);
@@ -184,10 +198,25 @@ mod tests {
        assert!((flash(tween, at(t0, 25), t0) - 0.75).abs() < 1e-6);
    }

+    #[test]
+    fn the_curve_is_the_design_systems() {
+        for motion in horizon_theme::MOTION {
+            for i in 0..=20 {
+                let t = i as f32 / 20.0;
+                assert_eq!(
+                    bezier(motion.curve, t),
+                    motion.ease(t),
+                    "{} at {t}",
+                    motion.name
+                );
+            }
+        }
+    }
+
    #[test]
    fn a_turn_takes_the_short_way_round() {
        let t0 = Instant::now();
-        let tween = Tween::new(MS(80), horizon_theme::MOVE);
+        let tween = Tween::new(MS(80), horizon_theme::MOVE.curve);
        // From up-left (7/8 of a turn) to up-right: through up, not round the bottom.
        let from = 7.0 * FRAC_PI_4;
        let half = turn(tween, at(t0, 1), t0, from, FRAC_PI_4);
@@ -1,6 +1,7 @@
 //! Room: what of a view Horizon's own HUD overlays may use. Vanilla's HUD elements are
 //! keep-outs; an overlay asks the room where it fits instead of assuming a fixed spot, so it
-//! doesn't cover them. Today the only keep-out is the boss bars at the top centre.
+//! doesn't cover them. The keep-outs: the boss bars at the top centre, and the status rows above
+//! the hotbar at the bottom centre.
 //!
 //! The room is built once a frame from what the HUD shows (`Game::hud_room` in gameplay). With
 //! nothing showing it is empty, and every overlay stays exactly where it always was.
@@ -34,6 +35,16 @@ pub const GAP: f32 = 2.0;
 pub enum Keep {
    /// The boss bars and their names at the top centre (`hud_overlays::boss_bars_bottom`).
    BossBars,
+    /// The survival rows above the hotbar at the bottom centre: health with its absorption rows,
+    /// armour, food or the mount's hearts, and air; from the highest row's top to the view's
+    /// bottom.
+    StatusRows,
+}
+impl Keep {
+    /// It sits at the top of the view, not the bottom.
+    fn at_top(self) -> bool {
+        matches!(self, Self::BossBars)
+    }
 }

 /// A view and the keep-outs its HUD shows this frame.
@@ -90,10 +101,20 @@ impl Room {
    /// bars' bottom, or 0 with none.
    pub fn top(&self) -> f32 {
        self.keeps()
-            .map(|(Keep::BossBars, [_, y, _, h])| y + h)
+            .filter(|(keep, _)| keep.at_top())
+            .map(|(_, [_, y, _, h])| y + h)
            .fold(0.0, f32::max)
    }

+    /// How far, in GUI px from the view's top, the keep-outs at the bottom reach up: the status
+    /// rows' top, or the view's height with none.
+    pub fn bottom(&self) -> f32 {
+        self.keeps()
+            .filter(|(keep, _)| !keep.at_top())
+            .map(|(_, [_, y, _, _])| y)
+            .fold(self.height, f32::min)
+    }
+
    /// Where a centred overlay that wants its top at `wanted` (GUI px) goes: at `wanted` unless
    /// a keep-out reaches past it (`top() > wanted`, a real overlap; touching isn't one), else
    /// `GAP` below that keep-out.
@@ -134,4 +155,15 @@ mod tests {
        assert_eq!(bars(36.0).below_top(18.0), 38.0);
        assert_eq!(bars(36.0).usable(), [0.0, 38.0, 500.0, 262.0]);
    }
+
+    #[test]
+    fn the_status_rows_are_kept_at_the_bottom_and_leave_the_top_alone() {
+        let room = Room::new(427.0, 240.0);
+        assert_eq!(room.bottom(), 240.0);
+        // Hearts and armour from y 191 down.
+        let rows = room.with(Keep::StatusRows, [122.0, 191.0, 182.0, 49.0]);
+        assert_eq!(rows.bottom(), 191.0);
+        assert_eq!(rows.top(), 0.0);
+        assert_eq!(rows.below_top(18.0), 18.0);
+    }
 }
@@ -38,6 +38,12 @@
 //! ```
 use crate::hud::{HudAtlas, HudBatch};
 use crate::hud_kit::{colour, fit};
+use crate::menu_style::{self, OverlayColours};
+
+/// The overlays' colours (`menu_style`, given at startup).
+fn overlay() -> &'static OverlayColours {
+    &menu_style::get().overlay
+}

 /// A pip under the strip: its size and the step from one to the next, in GUI px.
 pub const PIP: [f32; 2] = [3.0, 2.0];
@@ -45,8 +51,12 @@ pub const PIP_STEP: f32 = 5.0;
 /// How far, in GUI px, the arrows sit from the name.
 pub const ARROW_GAP: f32 = 4.0;
 /// An arrow with a page that way, and one at an end, with none.
-pub const ARROW: u32 = colour(horizon_theme::BACKDROP_MUTED, 255);
-pub const ARROW_OFF: u32 = colour(horizon_theme::BACKDROP_MUTED, 77);
+pub fn arrow_colour() -> u32 {
+    colour(overlay().backdrop_muted, 255)
+}
+pub fn arrow_off_colour() -> u32 {
+    colour(overlay().backdrop_muted, 77)
+}
 /// The pips (the selected one is white).
 pub const PIP_OFF: u32 = colour(0xFFFFFF, 89);
 pub const PIP_ON: u32 = colour(0xFFFFFF, 255);
@@ -65,9 +75,15 @@ pub const EDGE_FADE: f32 = 12.0;
 pub const FADE: [f32; 5] = [1.0, 0.7, 0.35, 0.15, 0.1];
 /// The selected tab's fill and text, and the others'.
 pub const SELECTED_FILL: u32 = colour(0xFFFFFF, 242);
-pub const SELECTED_TEXT: u32 = colour(horizon_theme::DARK.page, 255);
-pub const TAB_FILL: u32 = colour(horizon_theme::DARK.page, 191);
-pub const TAB_TEXT: u32 = colour(horizon_theme::BACKDROP_MUTED, 255);
+pub fn selected_text() -> u32 {
+    colour(overlay().page, 255)
+}
+pub fn tab_fill() -> u32 {
+    colour(overlay().page, 191)
+}
+pub fn tab_text() -> u32 {
+    colour(overlay().backdrop_muted, 255)
+}
 /// The line of text's height in GUI px (vanilla's font, without its shadow).
 const LINE: f32 = 8.0;

@@ -144,7 +160,11 @@ pub fn draw(batch: &mut HudBatch, atlas: &HudAtlas, strip: &Strip) {
            arrow,
            ax,
            ay,
-            if on { ARROW } else { ARROW_OFF },
+            if on {
+                arrow_colour()
+            } else {
+                arrow_off_colour()
+            },
            true,
        );
    }
@@ -282,9 +302,9 @@ pub fn draw_tabs(batch: &mut HudBatch, atlas: &HudAtlas, strip: &TabStrip, alpha
    for tab in &row.tabs {
        let [tx, ty, tw, th] = tab.area;
        let (fill, text) = if tab.selected {
-            (SELECTED_FILL, SELECTED_TEXT)
+            (SELECTED_FILL, selected_text())
        } else {
-            (TAB_FILL, TAB_TEXT)
+            (tab_fill(), tab_text())
        };
        let tab_start = batch.vertices.len();
        // Cut where the edges' fades start, so each fade runs over its own piece.
@@ -380,15 +400,16 @@ mod tests {
            let [ax, _] = strip.arrows[i];
            (batch.vertices.iter())
                .filter(|v| {
-                    (v.pos[0] - ax).abs() < 4.0 && v.color & 0x00FF_FFFF == ARROW & 0x00FF_FFFF
+                    (v.pos[0] - ax).abs() < 4.0
+                        && v.color & 0x00FF_FFFF == arrow_colour() & 0x00FF_FFFF
                })
                .map(|v| v.color >> 24)
                .max()
                .unwrap_or(0)
        };
        let first = collapsed(&atlas, &pages, 0, AREA);
-        assert_eq!(alpha(&first, 0), ARROW_OFF >> 24);
-        assert_eq!(alpha(&first, 1), ARROW >> 24);
+        assert_eq!(alpha(&first, 0), arrow_off_colour() >> 24);
+        assert_eq!(alpha(&first, 1), arrow_colour() >> 24);
    }

    #[test]
@@ -131,6 +131,23 @@ pub enum GuiDraw {

 pub const WHITE: u32 = 0xFFFF_FFFF;

+/// The highest top, in GUI px, of the draws that sit on the view (`None` for none): where a row
+/// of the HUD begins.
+pub fn draws_top(draws: &[GuiDraw]) -> Option<i32> {
+    draws
+        .iter()
+        .filter_map(|d| match *d {
+            GuiDraw::Sprite { y, .. }
+            | GuiDraw::AtlasSprite { y, .. }
+            | GuiDraw::Blit { y, .. }
+            | GuiDraw::Text { y, .. }
+            | GuiDraw::Item { y, .. } => Some(y),
+            GuiDraw::Fill { y0, .. } => Some(y0),
+            GuiDraw::Push(_) | GuiDraw::Pop => None,
+        })
+        .min()
+}
+
 fn sprite(sprite: &'static str, x: i32, y: i32, w: i32, h: i32) -> GuiDraw {
    GuiDraw::Sprite {
        sprite: Cow::Borrowed(sprite),
@@ -583,6 +583,9 @@ pub const BOSS_BAR_STEP: i32 = 10 + 9;
 pub const BOSS_BAR_HEIGHT: i32 = 5;
 /// A boss bar's sprite width, in GUI px; it is centred on the view.
 pub const BOSS_BAR_WIDTH: i32 = 182;
+/// Half the hotbar's width, in GUI px (`Hud`'s `screenWidth / 2 - 91`): the status rows above it
+/// span the same.
+pub const HOTBAR_HALF_WIDTH: i32 = 91;

 /// How many of `n` boss bars `BossHealthOverlay.extractRenderState` draws on a view `h` GUI px
 /// tall: it stops once the next bar's top reaches a third of the height (integer division,
@@ -67,7 +67,6 @@ mod jei_sprites;
 pub mod jigsaw_block;
 pub mod keypad;
 pub mod terrain_model;
-pub use horizon_polytone::colors as polytone_colors;
 pub use horizon_polytone::creative_tabs as polytone_creative_tabs;
 pub use horizon_world::json_folder;
 pub mod level_loading;
@@ -75,6 +74,7 @@ pub mod light;
 pub mod lod;
 pub mod logging;
 pub mod menu_blur;
+pub mod menu_style;
 pub mod mesher;
 pub mod minimap;
 pub mod mipmap;
@@ -89,6 +89,8 @@ pub mod options_fixes;
 pub mod options_ui;
 pub mod overlay;
 pub mod pack_browser;
+pub mod pack_formats;
+pub mod pack_hooks;
 pub mod pack_options_ui;
 pub mod pack_palette;
 pub mod pack_screen;
@@ -108,6 +110,8 @@ pub mod preedit;
 pub mod providers;
 pub mod pvp;
 pub mod pvp_hud;
+pub mod radial_editor;
+pub mod radial_overlay;
 pub mod random_source;
 pub mod screen_draw;
 pub mod screen_effects;
@@ -168,6 +172,7 @@ pub use horizon_client_input::key_names;
 pub use horizon_client_input::keybinds;
 pub use horizon_client_input::keymapping;
 pub use horizon_client_input::mouse;
+pub use horizon_client_input::radial;
 pub use horizon_client_input::window;
 pub use horizon_command as command;
 pub use horizon_items::blocks;
@@ -2593,8 +2593,7 @@ impl Lod {
        self.returned_at = std::time::Instant::now();
        let nodes = &self.plan.nodes;
        self.mesh_samples.retain(|key| nodes.contains(key));
-        // Queued tiles the view left are not sampled (a running one is
-        // dropped when it finishes, `finish_sample`).
+        // Queued tiles the view left are not sampled; a running one is dropped (`finish_sample`).
        drop_queued_samples(&self.shared, &mut self.pending, |key| {
            self.plan.nodes.contains(key)
        });
@@ -2680,6 +2679,7 @@ impl Lod {
            }
            if let Some((columns, mask)) = self.kept.take(&key) {
                self.ready.insert(key, columns);
+                self.sync_sample(key);
                if let Some(mask) = mask {
                    self.detail_masks.insert(key, mask);
                }
@@ -0,0 +1,150 @@
+//! The look of the screens vanilla doesn't have that the engine still draws: the settings pages
+//! (`graphics_style`), the HUD kit's tab strip, and the overlays drawn with `ui_theme` (the
+//! on-screen keyboard, the boot screen, the missing-resources window). Vanilla's screens never
+//! read it.
+//!
+//! The layer above gives it once at startup ([`install`]), before the first frame; the
+//! official game gives Horizon's design system (`docs/design-system.md`). With none given, the
+//! screens draw in [`NEUTRAL`]: vanilla's greys and chat colours, and no text where they would
+//! use their own fonts. A read is one atomic load, and only those screens make it.
+use std::sync::OnceLock;
+
+/// Colours as `0xRRGGBB`, sizes in dp (the launcher's logical pixels).
+#[derive(Clone, Copy, Debug, PartialEq)]
+pub struct MenuStyle {
+    pub settings: SettingsColours,
+    pub overlay: OverlayColours,
+    pub sizes: Sizes,
+    /// The overlays' TrueType faces; none: they draw no text.
+    pub fonts: Option<Fonts>,
+}
+
+/// The settings pages: square panels of dark glass over the world, flat controls, one face.
+#[derive(Clone, Copy, Debug, PartialEq, Eq)]
+pub struct SettingsColours {
+    /// The plate behind everything, drawn see-through.
+    pub page: u32,
+    /// Text, and the light the panels, rules, hovers and controls are drawn in.
+    pub ink: u32,
+    /// Secondary text and values.
+    pub ink_soft: u32,
+    /// Labels, descriptions, what can't be used.
+    pub muted: u32,
+    /// Wells and the dark edge of small marks.
+    pub outline: u32,
+    /// Focus, a checked box, a slider's fill.
+    pub accent: u32,
+    /// The one main button, and while hovered.
+    pub face: u32,
+    pub face_hover: u32,
+    pub success: u32,
+    pub warn: u32,
+    pub danger: u32,
+}
+
+/// Overlays drawn over the game (the HUD kit's tab strip, `ui_theme`'s overlays).
+#[derive(Clone, Copy, Debug, PartialEq, Eq)]
+pub struct OverlayColours {
+    /// The dark page under text and tabs.
+    pub page: u32,
+    /// Muted text over a veiled backdrop.
+    pub backdrop_muted: u32,
+    /// Text and the light hover and pressed plates are drawn in.
+    pub ink: u32,
+    /// Secondary text and values.
+    pub ink_soft: u32,
+    /// One-pixel rules between rows.
+    pub rule: u32,
+    /// The main action, and its text.
+    pub accent: u32,
+    pub on_accent: u32,
+    /// A lit choice and its bright edge (the controller dial's sector).
+    pub lit: u32,
+    pub lit_edge: u32,
+}
+
+/// `ui_theme`'s type scale and shapes, in dp.
+#[derive(Clone, Copy, Debug, PartialEq)]
+pub struct Sizes {
+    pub caption: f32,
+    pub label: f32,
+    pub ui: f32,
+    pub body: f32,
+    pub title: f32,
+    /// The boot screen's wordmark at its smallest, and its console lines.
+    pub display: f32,
+    pub micro: f32,
+    /// Fields; plates (hover rows, selection); a large control's height.
+    pub radius: f32,
+    pub radius_plate: f32,
+    pub control_large: f32,
+}
+
+/// TrueType faces (`ui_theme::Face`).
+#[derive(Clone, Copy, Debug, PartialEq, Eq)]
+pub struct Fonts {
+    pub regular: &'static [u8],
+    pub medium: &'static [u8],
+    pub semibold: &'static [u8],
+    pub mono: &'static [u8],
+}
+
+/// The look with nothing given: vanilla's greys and chat colours.
+pub const NEUTRAL: MenuStyle = MenuStyle {
+    settings: SettingsColours {
+        page: 0x101010,
+        ink: 0xffffff,
+        ink_soft: 0xe0e0e0,
+        muted: 0xa0a0a0,
+        outline: 0x000000,
+        accent: 0xffffff,
+        face: 0x555555,
+        face_hover: 0x6f6f6f,
+        success: 0x55ff55,
+        warn: 0xffff55,
+        danger: 0xff5555,
+    },
+    overlay: OverlayColours {
+        page: 0x101010,
+        backdrop_muted: 0xa0a0a0,
+        ink: 0xffffff,
+        ink_soft: 0xe0e0e0,
+        rule: 0x303030,
+        accent: 0xffffff,
+        on_accent: 0x000000,
+        lit: 0xffffff,
+        lit_edge: 0xffffff,
+    },
+    sizes: Sizes {
+        caption: 12.0,
+        label: 13.0,
+        ui: 14.0,
+        body: 15.0,
+        title: 28.0,
+        display: 44.0,
+        micro: 11.0,
+        radius: 0.0,
+        radius_plate: 0.0,
+        control_large: 40.0,
+    },
+    fonts: None,
+};
+
+static STYLE: OnceLock<MenuStyle> = OnceLock::new();
+
+/// Give the menus their look: call it once at startup. A second call keeps the first look and
+/// returns false.
+pub fn install(style: MenuStyle) -> bool {
+    STYLE.set(style).is_ok()
+}
+
+/// The look given to [`install`], or [`NEUTRAL`].
+#[inline]
+pub fn get() -> &'static MenuStyle {
+    STYLE.get().unwrap_or(&NEUTRAL)
+}
+
+/// `0xRRGGBB` and an alpha in the HUD's colour encoding (`0xAABBGGRR`).
+pub const fn hud_colour(rgb: u32, alpha: u8) -> u32 {
+    (alpha as u32) << 24 | (rgb & 0xff) << 16 | (rgb >> 8 & 0xff) << 8 | (rgb >> 16 & 0xff)
+}
@@ -1,6 +1,7 @@
 //! Optional, texture-matched overlays drawn full bright over their base texture in the same
-//! terrain fragment: native mods' (`<ns>:emissive/...`) and OptiFine's emissive block textures
-//! (`block/stone_e.png` beside `block/stone.png`). No extra draw calls or world light changes.
+//! terrain fragment: native mods' (`<ns>:emissive/...`) and a pack's emissive block textures
+//! (OptiFine's `block/stone_e.png` beside `block/stone.png`, the suffix from the pack formats,
+//! [`crate::pack_hooks`]). No extra draw calls or world light changes.
 use crate::sprites::Sprites;
 use std::{collections::BTreeMap, path::Path};

@@ -35,14 +36,12 @@ fn tile_file(name: &str) -> Option<&str> {
    name.strip_suffix(".png")
 }

-/// OptiFine's emissive overlays of the block sprites already loaded (what the terrain draws;
-/// items draw from the HUD atlas): for each
-/// `<ns>:block/<name>`, or connected-texture tile `assets/<ns>/.../<name>.png`, whose
-/// `<name><suffix>.png` sits beside it, the overlay is loaded too and paired with it, blocks
-/// first, then tiles, each by name, at most [`MAX`] - [`NATIVE`] (native mods keep their share of
-/// the table). A pack without such files adds nothing.
-pub fn load_optifine(root: &Path, sprites: &mut Sprites) -> Vec<(String, String)> {
-    let suffix = horizon_optifine::emissive::suffix(root);
+/// A pack's emissive overlays of the block sprites already loaded (what the terrain draws;
+/// items draw from the HUD atlas): for each `<ns>:block/<name>`, or connected-texture tile
+/// `assets/<ns>/.../<name>.png`, whose `<name><suffix>.png` sits beside it, the overlay is loaded
+/// too and paired with it, blocks first, then tiles, each by name, at most [`MAX`] - [`NATIVE`]
+/// (native mods keep their share of the table). A pack without such files adds nothing.
+pub fn load_overlays(root: &Path, suffix: &str, sprites: &mut Sprites) -> Vec<(String, String)> {
    // Blocks with identical pixels share a layer (and the shader pairs by layer): a shared
    // base would glow on every block that shares it, so it gets no overlay.
    let mut sharing: BTreeMap<u32, usize> = BTreeMap::new();
@@ -56,8 +55,8 @@ pub fn load_optifine(root: &Path, sprites: &mut Sprites) -> Vec<(String, String)
            sharing[layer] == 1
                && (name
                    .split_once(':')
-                    .is_some_and(|(_, p)| p.starts_with("block/") && !p.ends_with(&suffix))
-                    || tile_file(name).is_some_and(|stem| !stem.ends_with(&suffix)))
+                    .is_some_and(|(_, p)| p.starts_with("block/") && !p.ends_with(suffix))
+                    || tile_file(name).is_some_and(|stem| !stem.ends_with(suffix)))
        })
        .map(|(name, _)| name.clone())
        .collect();
@@ -110,7 +109,7 @@ pub fn load_optifine(root: &Path, sprites: &mut Sprites) -> Vec<(String, String)
 pub const CUTOUT: u32 = 1 << 31;

 /// The frame's overlay table: native mods' pairs (at most [`NATIVE`] requested), then the packs'
-/// OptiFine pairs flagged [`CUTOUT`] (at most [`MAX`] - [`NATIVE`], as [`load_optifine`] loads),
+/// OptiFine pairs flagged [`CUTOUT`] (at most [`MAX`] - [`NATIVE`], as [`load_overlays`] loads),
 /// one per base layer with native mods' first, sorted by base layer for the shader's early exit.
 pub fn table<'a>(
    layers: &BTreeMap<String, u32>,
@@ -204,7 +203,7 @@ mod tests {
        // Items draw from the HUD atlas, not the terrain: no pair.
        sprites.insert(&root, "minecraft:item/stick").unwrap();
        // glowstone isn't loaded: its overlay pairs with nothing.
-        let pairs = load_optifine(&root, &mut sprites);
+        let pairs = load_overlays(&root, "_e", &mut sprites);
        assert_eq!(
            pairs,
            [(
@@ -215,9 +214,6 @@ mod tests {
        assert!(sprites.layers.contains_key("minecraft:block/stone_e"));
        assert!(!sprites.layers.contains_key("minecraft:block/granite_e"));
        // The pack's own suffix.
-        let props = root.join("assets/minecraft/optifine/emissive.properties");
-        std::fs::create_dir_all(props.parent().unwrap()).unwrap();
-        std::fs::write(&props, "suffix.emissive=_glow").unwrap();
        // Connected-texture tiles pair with the overlay beside them.
        let tiles = root.join("assets/minecraft/optifine/ctm/lamp");
        png(&tiles.join("0.png"), 230);
@@ -234,7 +230,7 @@ mod tests {
                .insert_file(&root, &format!("assets/minecraft/optifine/{tile}.png"))
                .unwrap();
        }
-        let pairs = load_optifine(&root, &mut sprites);
+        let pairs = load_overlays(&root, "_glow", &mut sprites);
        assert_eq!(
            pairs,
            // Blocks first, then tiles.
@@ -18,6 +18,8 @@ use crate::{
    ui,
 };

+mod shell_pages;
+
 fn tr(key: &str) -> Text {
    Text::translate(key, &[])
 }
@@ -322,6 +324,8 @@ impl Opt {
            Opt::PadNintendoButtons => "horizon.options.nintendo_buttons",
            Opt::PadKeyboard => "horizon.options.on_screen_keyboard",
            Opt::PadGameplayGuide => "horizon.options.gameplay_guide",
+            Opt::PadRadialMode => "horizon.options.radial_mode",
+            Opt::PadRadialStick => "horizon.options.radial_stick",
            Opt::ModelPart(i) => [
                "options.modelPart.cape",
                "options.modelPart.jacket",
@@ -339,6 +343,7 @@ impl Opt {
            Opt::SharePresence => "options.sharePresence",
            Opt::DirectionalAudio => "options.directionalAudio",
            Opt::MusicToast => "options.musicToast",
+            Opt::Page(page, row) => pages::slider_caption(page, row),
        }
    }
    pub(crate) fn kind(self, s: &Settings) -> Kind {
@@ -402,6 +407,7 @@ impl Opt {
            Opt::PadLookDeadzone => unit(s.controller.look_deadzone, 0.0, 0.5),
            Opt::PadTriggerThreshold => unit(s.controller.trigger_threshold, 0.1, 0.9),
            Opt::SprintWindow => unit(s.sprint_window as f32, 0.0, 10.0),
+            Opt::Page(page, row) => pages::slider_kind(page, row),
            _ => Kind::Cycle,
        }
    }
@@ -878,6 +884,8 @@ impl Opt {
                gamepad::TextKeyboard::Horizon => "horizon.options.keyboard.horizon",
                gamepad::TextKeyboard::Steam => "horizon.options.keyboard.steam",
            }),
+            Opt::PadRadialMode | Opt::PadRadialStick => self.radial_text(s),
+            Opt::Page(page, row) => pages::slider_text(page, row),
            _ => Text::empty(),
        }
    }
@@ -952,6 +960,7 @@ impl Opt {
            Opt::PadLookDeadzone => s.controller.look_deadzone = step(0.0, 50.0) / 100.0,
            Opt::PadTriggerThreshold => s.controller.trigger_threshold = step(10.0, 90.0) / 100.0,
            Opt::SprintWindow => s.sprint_window = step(0.0, 10.0) as i32,
+            Opt::Page(page, row) => pages::slide(page, row, v),
            _ => {}
        }
        if self.affects_preset() {
@@ -1197,6 +1206,7 @@ impl Opt {
                    .unwrap_or(0) as u8;
                s.controller.keyboard = all[usize::from(next(i, 3))];
            }
+            Opt::PadRadialMode | Opt::PadRadialStick => self.radial_step(s, back),
            _ => {}
        }
        if self.affects_preset() {
@@ -1348,6 +1358,11 @@ pub enum Page {
    /// Horizon's controller settings and button binds.
    Controller,
    PadBinds,
+    /// The radial menu's pages (`radial_editor`), on the settings shell, and a page's name.
+    ControllerRadial,
+    ControllerRadialName,
+    /// The list of every action for one of its slots.
+    ControllerRadialPick,
    Extras,
    /// PvP & HUD (`pvp`): the extras a PvP player sets, on their own page.
    Pvp,
@@ -1624,8 +1639,6 @@ pub struct OptionsUi {
    /// The native mod's key waiting: (mod, key) in `mods.installed`, or a registered page's
    /// (page, row) ([`pages::PAGE_KEY`]).
    selected_native_key: Option<(usize, usize)>,
-    /// The pages crates registered (`horizon_hooks::pages`).
-    pages: &'static [&'static dyn horizon_hooks::pages::Page],
    /// Bindings: the action waiting for a pad button.
    pub selected_pad_action: Option<&'static str>,
    /// The glyphs menus show (`Glyphs::of`: the setting, else the pad's family, and a Nintendo
@@ -1681,6 +1694,10 @@ pub struct OptionsUi {
    controller: shell::Shell<crate::controller_ui::ControllerScreen>,
    /// Horizon Extras, on the settings shell.
    extras: shell::Shell<crate::extras_ui::ExtrasScreen>,
+    /// The radial menu's pages, on the settings shell.
+    radial: shell::Shell<crate::radial_editor::RadialScreen>,
+    /// The list of actions for one of the radial menu's slots.
+    radial_pick: shell::Shell<crate::radial_editor::PickScreen>,
    /// Shaders: the shader packs and the picked one's options, on the settings shell.
    shader: shell::Shell<crate::shader_ui::ShaderScreen>,
    /// The Pack Options page, and the packs' Polytone config entries by pack id (the game
@@ -1737,7 +1754,6 @@ impl Default for OptionsUi {
            scrollbar_drag_y: None,
            selected_key: None,
            selected_native_key: None,
-            pages: horizon_hooks::pages::engine::all(),
            selected_pad_action: None,
            pad_glyphs: crate::pad_glyph::Glyphs::default(),
            pad_driving: false,
@@ -1766,6 +1782,8 @@ impl Default for OptionsUi {
            graphics: Default::default(),
            controller: Default::default(),
            extras: Default::default(),
+            radial: Default::default(),
+            radial_pick: Default::default(),
            shader: Default::default(),
            pack_options: Default::default(),
            pack_configs: Default::default(),
@@ -1869,25 +1887,6 @@ fn wide_extras(s: &Settings, width: impl Fn(&str) -> f32) -> Vec<crate::extras::
        })
        .collect()
 }
-/// What a button opening one of Horizon's pages says on hover.
-fn horizon_page_tooltip(page: Page) -> Option<&'static str> {
-    Some(match page {
-        Page::Horizon => "horizon.pages.settings.tooltip",
-        Page::Studio => "horizon.pages.studio.tooltip",
-        Page::Graphics => "horizon.pages.graphics.tooltip",
-        Page::GraphicsAdvanced => "horizon.pages.graphics_advanced.tooltip",
-        Page::Controller => "horizon.pages.controller.tooltip",
-        Page::Extras => "horizon.pages.extras.tooltip",
-        Page::Pvp => "horizon.pages.pvp.tooltip",
-        Page::Agent => "horizon.pages.agent.tooltip",
-        Page::SplitProfiles => "horizon.pages.split_profiles.tooltip",
-        Page::ShaderPacks => "horizon.pages.shader_packs.tooltip",
-        Page::Mods => "horizon.pages.mods.tooltip",
-        Page::SplitSetup => "horizon.pages.split_setup.tooltip",
-        Page::Music => "horizon.pages.music.tooltip",
-        _ => return None,
-    })
-}
 /// Rows of an OptionsList: (big?, options) or a header.
 enum Row {
    Big(Opt),
@@ -1907,14 +1906,17 @@ fn tooltip_text(s: &Settings, wd: &Widget) -> Option<Text> {
            return None;
        };
        let key = opt.tooltip_key(s);
-        return lang::has(&key).then(|| tr(&key));
+        let Opt::Page(page, row) = opt else {
+            return lang::has(&key).then(|| tr(&key));
+        };
+        return pages::tooltip(*page, *row);
    };
    let mut tip = None;
    if let Act::Extra(item) = act {
        tip = Some(Text::literal(item.description_text()));
    }
    if let Act::Push(page) = act
-        && let Some(text) = horizon_page_tooltip(*page)
+        && let Some(text) = pages::horizon_page_tooltip(*page)
    {
        tip = Some(tr(text));
    }
@@ -1934,6 +1936,7 @@ fn tooltip_text(s: &Settings, wd: &Widget) -> Option<Text> {
    }
    match act {
        Act::Cycle(opt) if !opt.available() => Some(tr("horizon.options.unavailable")),
+        Act::PageRow(page, row) => pages::tooltip(*page, *row),
        Act::ToggleMod(i) => match s.mods.installed.get(*i) {
            Some(installed) => {
                let description = installed
@@ -2126,6 +2129,7 @@ impl OptionsUi {
                    .pack_screen
                    .as_ref()
                    .is_some_and(|p| p.search_focused()),
+                Page::ControllerRadialName => self.radial_name_typing(),
                _ => match self.shell() {
                    Some(shell) => shell.typing(),
                    None => self.settings_search_active(),
@@ -2258,95 +2262,16 @@ impl OptionsUi {
            self.studio.refresh();
        }
    }
-    /// The open page's screen on the settings shell. This, with `shell_mut`, is all a screen
-    /// needs here: drawing, clicks, the wheel, a stick's scrolling, keys and typing all go
-    /// through them, so no input path can miss one.
-    fn shell(&self) -> Option<&dyn shell::Hosted> {
-        match self.page() {
-            Page::Extras => Some(&self.extras),
-            page if Self::graphics_page(page).is_some() => Some(&self.graphics),
-            page if Self::controller_page(page).is_some() => Some(&self.controller),
-            page if Self::shader_page(page).is_some() => Some(&self.shader),
-            _ => None,
-        }
-    }
-    fn shell_mut(&mut self) -> Option<&mut dyn shell::Hosted> {
-        self.graphics.screen.output = self.output;
-        match self.page() {
-            Page::Extras => Some(&mut self.extras),
-            page if Self::graphics_page(page).is_some() => Some(&mut self.graphics),
-            page if Self::controller_page(page).is_some() => Some(&mut self.controller),
-            page if Self::shader_page(page).is_some() => Some(&mut self.shader),
-            _ => None,
-        }
-    }
    /// A controller's or the keyboard's focus landed on `rect`: a row of a shell screen's list
    /// that is partly hidden scrolls all into view. How far it moved down, when it moved.
    pub fn reveal(&mut self, s: &Settings, size: (f32, f32), rect: [f32; 4]) -> Option<f32> {
        self.shell_mut()?.reveal(s, size, rect)
    }
-    /// The window's size, for the graphics and controller screens' rows that step an option
-    /// (`Opt::cycle`, which a fullscreen resolution needs): before each input that can press one.
-    fn shell_framebuffers(&mut self) {
-        self.graphics.screen.framebuffer = self.framebuffer;
-        self.controller.screen.framebuffer = self.framebuffer;
-    }
-    /// Who and what Controller Settings is about: the game sets it before each draw.
-    pub fn set_controller_context(&mut self, context: crate::controller_ui::Context) {
-        self.controller.screen.context = context;
-    }
-    /// The binding the screen waits on: a controller button's, else a key's.
-    fn waiting(&self) -> Option<shell::Capture> {
-        let pad = self.selected_pad_action.map(shell::Capture::Pad);
-        pad.or(self.selected_key.map(shell::Capture::Key))
-    }
-    /// What a shell screen's outputs do to these options.
-    fn shell_events(&mut self, s: &mut Settings, outputs: Vec<shell::Output>) -> Vec<Event> {
-        let mut events = Vec::new();
-        for output in outputs {
-            match output {
-                shell::Output::Event(event) => events.push(event),
-                shell::Output::Bind(shell::Capture::Key(name)) => self.selected_key = Some(name),
-                shell::Output::Bind(shell::Capture::Pad(action)) => {
-                    self.selected_pad_action = Some(action)
-                }
-                shell::Output::Push(page) => {
-                    if page == Page::HdrCalibration {
-                        self.calibration =
-                            Some(crate::hdr_calibration::Calibration::new(s, &self.output));
-                    }
-                    self.push(page);
-                }
-                shell::Output::Done => events.extend(self.back(s)),
-            }
-        }
-        events
-    }
-    /// Where the shader screen opens for `page`, if it is one of its pages.
-    fn shader_page(page: Page) -> Option<crate::shader_ui::Tab> {
-        match page {
-            Page::ShaderPacks => Some(crate::shader_ui::Tab::Packs),
-            Page::ShaderOptions => Some(crate::shader_ui::Tab::Screen(0)),
-            _ => None,
-        }
-    }
-    /// Where the controller screen opens for `page`, if it is one of its pages.
-    fn controller_page(page: Page) -> Option<crate::controller_ui::Page> {
-        match page {
-            Page::Controller => Some(crate::controller_ui::Page::General),
-            Page::PadBinds => Some(crate::controller_ui::Page::Bindings),
-            _ => None,
-        }
-    }
    /// Whether a video settings screen is open, Horizon's or vanilla's: the fullscreen mode
    /// waits for it to close, and Ctrl with the wheel steps the GUI scale.
    pub fn video_open(&self) -> bool {
        self.page() == Page::Video || Self::graphics_page(self.page()).is_some()
    }
-    /// Whether the controller screen is open: a controller button pressed now may bind.
-    pub fn controller_open(&self) -> bool {
-        Self::controller_page(self.page()).is_some()
-    }
    /// Where the graphics screen opens for `page`, if it is one of its pages.
    fn graphics_page(page: Page) -> Option<crate::graphics_ui::Page> {
        match page {
@@ -2383,6 +2308,9 @@ impl OptionsUi {
                "options.videoTitle"
            }
            Page::Controller | Page::PadBinds => "horizon.pages.controller",
+            Page::ControllerRadial => "horizon.pages.controller_radial",
+            Page::ControllerRadialName => "horizon.radial.name_title",
+            Page::ControllerRadialPick => "horizon.radial.pick_title",
            Page::Extras => "horizon.pages.extras",
            Page::Pvp => "horizon.pages.pvp",
            Page::Credits => "credits_and_attribution.screen.title",
@@ -3616,6 +3544,9 @@ impl OptionsUi {
        }
        let waiting = self.waiting();
        let in_world = self.in_world;
+        if self.draw_radial_name(batch, atlas, cursor, in_world) {
+            return;
+        }
        if let Some(shell) = self.shell_mut() {
            shell.draw(s, batch, atlas, cursor, in_world, waiting);
            // The keys lay the screen out at the size it was drawn at.
@@ -3967,6 +3898,9 @@ impl OptionsUi {
            let outcome = c.click(&atlas.font, (x, y), size, drag);
            return self.calibration_outcome(s, outcome);
        }
+        if self.page() == Page::ControllerRadialName {
+            return self.click_radial_name(s, atlas, (x, y), size, drag || right);
+        }
        if self.shell().is_some() {
            // Waiting on a controller button: a click cancels the wait.
            if !drag && self.selected_pad_action.take().is_some() {
@@ -4662,6 +4596,8 @@ impl OptionsUi {
            self.scroll = 0.0;
        } else if self.page() == Page::SplitProfiles {
            self.split_profiles.type_text(text);
+        } else if self.page() == Page::ControllerRadialName {
+            self.type_radial_name(text);
        } else if let Some(shell) = self.shell_mut() {
            if shell.typing() {
                shell.type_text(text);
@@ -4697,6 +4633,9 @@ impl OptionsUi {
        if self.page() == Page::SplitProfiles {
            return self.split_profiles.shortcut(shortcut, clipboard);
        }
+        if self.page() == Page::ControllerRadialName {
+            return self.radial_name_shortcut(shortcut, clipboard);
+        }
        if let Some(shell) = self.shell_mut() {
            return shell.shortcut(shortcut, clipboard);
        }
@@ -4800,6 +4739,9 @@ impl OptionsUi {
        if self.page() == Page::SplitProfiles && self.split_profiles.key(key, text) {
            return Vec::new();
        }
+        if self.page() == Page::ControllerRadialName {
+            return self.radial_name_key(s, key, text);
+        }

        // The size it was drawn at; before the first draw, one its keys can lay out at.
        let gui = if self.size.0 > 0.0 && self.size.1 > 0.0 {
@@ -0,0 +1,302 @@
+//! The pages Options shows on the settings shell (`settings_shell`): which shell each page
+//! opens, what a shell's outputs do here, and the radial menu's pages (`radial_editor`), whose
+//! name entry is drawn here in place of a shell, and whose rows of Controller Settings step here.
+use super::{Event, OptionsUi, Page, tr};
+use crate::{
+    gamepad,
+    hud::{HudAtlas, HudBatch},
+    radial_editor::Named,
+    settings::{Opt, Settings},
+    settings_shell as shell,
+    text::Text,
+};
+
+impl OptionsUi {
+    /// The open page's screen on the settings shell. This, with `shell_mut`, is all a screen
+    /// needs here: drawing, clicks, the wheel, a stick's scrolling, keys and typing all go
+    /// through them, so no input path can miss one.
+    pub(super) fn shell(&self) -> Option<&dyn shell::Hosted> {
+        match self.page() {
+            Page::Extras => Some(&self.extras),
+            page if Self::graphics_page(page).is_some() => Some(&self.graphics),
+            Page::ControllerRadial => Some(&self.radial),
+            Page::ControllerRadialPick => Some(&self.radial_pick),
+            page if Self::controller_page(page).is_some() => Some(&self.controller),
+            page if Self::shader_page(page).is_some() => Some(&self.shader),
+            _ => None,
+        }
+    }
+    pub(super) fn shell_mut(&mut self) -> Option<&mut dyn shell::Hosted> {
+        self.graphics.screen.output = self.output;
+        match self.page() {
+            Page::Extras => Some(&mut self.extras),
+            page if Self::graphics_page(page).is_some() => Some(&mut self.graphics),
+            Page::ControllerRadial => Some(&mut self.radial),
+            Page::ControllerRadialPick => Some(&mut self.radial_pick),
+            page if Self::controller_page(page).is_some() => Some(&mut self.controller),
+            page if Self::shader_page(page).is_some() => Some(&mut self.shader),
+            _ => None,
+        }
+    }
+    /// Where the open shell screen asked the focus to open (a radial slot's list, on the slot's
+    /// action), for a controller's focus to land there.
+    pub fn shell_opened_focus(&self) -> Option<[f32; 4]> {
+        self.shell()?.opened_focus()
+    }
+    /// The clicks until it is set back are a controller's Left or Right on a row: a choice of a
+    /// settings shell steps, rather than opens.
+    pub fn pad_clicks_step(&mut self, on: bool) {
+        if on {
+            if let Some(shell) = self.shell_mut() {
+                shell.clicks_step(true);
+            }
+            return;
+        }
+        // Every shell: the click may have changed the page.
+        let shells: [&mut dyn shell::Hosted; 6] = [
+            &mut self.extras,
+            &mut self.graphics,
+            &mut self.controller,
+            &mut self.radial,
+            &mut self.radial_pick,
+            &mut self.shader,
+        ];
+        for shell in shells {
+            shell.clicks_step(false);
+        }
+    }
+    /// The controller's focus landed there.
+    pub fn clear_shell_opened_focus(&mut self) {
+        if let Some(shell) = self.shell_mut() {
+            shell.clear_opened_focus();
+        }
+    }
+    /// The window's size, for the graphics and controller screens' rows that step an option
+    /// (`Opt::cycle`, which a fullscreen resolution needs): before each input that can press one.
+    pub(super) fn shell_framebuffers(&mut self) {
+        self.graphics.screen.framebuffer = self.framebuffer;
+        self.controller.screen.framebuffer = self.framebuffer;
+    }
+    /// Who and what Controller Settings is about: the game sets it before each draw.
+    pub fn set_controller_context(&mut self, context: crate::controller_ui::Context) {
+        self.controller.screen.context = context;
+    }
+    /// The binding the screen waits on: a controller button's, else a key's.
+    pub(super) fn waiting(&self) -> Option<shell::Capture> {
+        let pad = self.selected_pad_action.map(shell::Capture::Pad);
+        pad.or(self.selected_key.map(shell::Capture::Key))
+    }
+    /// What a shell screen's outputs do to these options.
+    pub(super) fn shell_events(
+        &mut self,
+        s: &mut Settings,
+        outputs: Vec<shell::Output>,
+    ) -> Vec<Event> {
+        let mut events = Vec::new();
+        for output in outputs {
+            match output {
+                shell::Output::Event(event) => events.push(event),
+                shell::Output::Bind(shell::Capture::Key(name)) => self.selected_key = Some(name),
+                shell::Output::Bind(shell::Capture::Pad(action)) => {
+                    self.selected_pad_action = Some(action)
+                }
+                shell::Output::Push(page) => {
+                    if page == Page::HdrCalibration {
+                        self.calibration =
+                            Some(crate::hdr_calibration::Calibration::new(s, &self.output));
+                    }
+                    self.push(page);
+                    // A slot's list, for the slot, opening on what it holds.
+                    if page == Page::ControllerRadialPick
+                        && let Some(at) = self.radial.screen.picking.take()
+                    {
+                        let row = self.radial_pick.screen.open_on(at, &s.controller.radial);
+                        self.radial_pick.focus_soon(row);
+                    }
+                }
+                shell::Output::Done => {
+                    // Back from a slot's list, the focus is on the slot.
+                    let slot = (self.page() == Page::ControllerRadialPick)
+                        .then(|| self.radial_pick.screen.at());
+                    events.extend(self.back(s));
+                    if let Some((page, slot)) = slot {
+                        self.radial
+                            .focus_soon(crate::radial_editor::RadialRow::Slot(page, slot));
+                    }
+                }
+            }
+        }
+        // A pick on a slot's list is a change of the radial page's, which its Undo takes back.
+        if self.radial_pick.screen.take_picked() {
+            self.radial.changed_elsewhere();
+        }
+        // A radial page added or deleted: the one to show now.
+        if let Some(page) = self.radial.screen.take_shown() {
+            self.radial.show(page);
+        }
+        events
+    }
+    /// What a press on a radial page's name does here.
+    pub(super) fn name_events(
+        &mut self,
+        named: crate::radial_editor::Named,
+        s: &mut Settings,
+    ) -> Vec<Event> {
+        use crate::radial_editor::Named;
+        let mut events = vec![Event::ButtonClick];
+        match named {
+            Named::Nothing => return Vec::new(),
+            Named::Done => {
+                let entry = self.radial.screen.naming.take();
+                if entry.is_some_and(|entry| entry.apply(&mut s.controller.radial)) {
+                    self.radial.changed_elsewhere();
+                }
+                events.push(Event::Changed);
+                events.extend(self.back(s));
+            }
+            Named::Back => events.extend(self.back(s)),
+        }
+        events
+    }
+    /// Where the shader screen opens for `page`, if it is one of its pages.
+    pub(super) fn shader_page(page: Page) -> Option<crate::shader_ui::Tab> {
+        match page {
+            Page::ShaderPacks => Some(crate::shader_ui::Tab::Packs),
+            Page::ShaderOptions => Some(crate::shader_ui::Tab::Screen(0)),
+            _ => None,
+        }
+    }
+    /// Where the controller screen opens for `page`, if it is one of its pages.
+    pub(super) fn controller_page(page: Page) -> Option<crate::controller_ui::Page> {
+        match page {
+            Page::Controller => Some(crate::controller_ui::Page::General),
+            Page::PadBinds => Some(crate::controller_ui::Page::Bindings),
+            _ => None,
+        }
+    }
+    /// Whether the controller screen is open: a controller button pressed now may bind.
+    pub fn controller_open(&self) -> bool {
+        Self::controller_page(self.page()).is_some()
+    }
+    /// The radial screens' glyphs this frame, and the name of a radial page being typed, drawn
+    /// in place of a shell: whether it was.
+    pub(super) fn draw_radial_name(
+        &mut self,
+        batch: &mut HudBatch,
+        atlas: &HudAtlas,
+        cursor: (f32, f32),
+        in_world: bool,
+    ) -> bool {
+        self.radial.screen.glyphs = self.pad_glyphs;
+        if self.page() == Page::ControllerRadialName
+            && let Some(entry) = &mut self.radial.screen.naming
+        {
+            entry.draw(batch, atlas, cursor, in_world);
+            return true;
+        }
+        false
+    }
+    /// A click on a radial page's name entry (`ignored`: a drag or a right click).
+    pub(super) fn click_radial_name(
+        &mut self,
+        s: &mut Settings,
+        atlas: &HudAtlas,
+        at: (f32, f32),
+        size: (f32, f32),
+        ignored: bool,
+    ) -> Vec<Event> {
+        let entry = self.radial.screen.naming.as_mut();
+        let named = match entry.filter(|_| !ignored) {
+            Some(entry) => entry.click(atlas, at, size),
+            None => Named::Nothing,
+        };
+        self.name_events(named, s)
+    }
+    /// Whether a radial page's name is being typed.
+    pub(super) fn radial_name_typing(&self) -> bool {
+        self.radial
+            .screen
+            .naming
+            .as_ref()
+            .is_some_and(|n| n.typing())
+    }
+    /// Text typed into a radial page's name.
+    pub(super) fn type_radial_name(&mut self, text: &str) {
+        if let Some(entry) = &mut self.radial.screen.naming {
+            entry.type_text(text);
+        }
+    }
+    /// An edit shortcut in a radial page's name: whether it did something.
+    pub(super) fn radial_name_shortcut(
+        &mut self,
+        shortcut: crate::clipboard::EditShortcut,
+        clipboard: &mut dyn crate::clipboard::Clipboard,
+    ) -> bool {
+        let entry = self.radial.screen.naming.as_mut();
+        entry.is_some_and(|entry| entry.shortcut(shortcut, clipboard))
+    }
+    /// A key on a radial page's name entry.
+    pub(super) fn radial_name_key(
+        &mut self,
+        s: &mut Settings,
+        key: winit::keyboard::KeyCode,
+        text: Option<&str>,
+    ) -> Vec<Event> {
+        let named = match &mut self.radial.screen.naming {
+            Some(entry) => entry.key(key, text),
+            // Nothing to name: Escape still leaves.
+            None if key == winit::keyboard::KeyCode::Escape => Named::Back,
+            None => Named::Nothing,
+        };
+        self.name_events(named, s)
+    }
+}
+
+impl Opt {
+    /// The radial menu's rows of Controller Settings: their value.
+    pub(super) fn radial_text(self, s: &Settings) -> Text {
+        match self {
+            Opt::PadRadialMode => tr(match s.controller.radial_mode {
+                gamepad::RadialMode::Hold => "options.key.hold",
+                gamepad::RadialMode::Toggle => "options.key.toggle",
+            }),
+            Opt::PadRadialStick => tr(match s.controller.radial_stick {
+                gamepad::RadialStick::Right => "horizon.options.radial_stick.right",
+                gamepad::RadialStick::Left => "horizon.options.radial_stick.left",
+                gamepad::RadialStick::Either => "horizon.options.radial_stick.either",
+            }),
+            _ => Text::empty(),
+        }
+    }
+    /// The radial menu's rows of Controller Settings: a step, back or on.
+    pub(super) fn radial_step(self, s: &mut Settings, back: bool) {
+        let next = |n: u8, count: u8| {
+            if back {
+                (n + count - 1) % count
+            } else {
+                (n + 1) % count
+            }
+        };
+        match self {
+            Opt::PadRadialMode => {
+                let all = gamepad::RadialMode::ALL;
+                let i = all
+                    .iter()
+                    .position(|m| *m == s.controller.radial_mode)
+                    .unwrap_or(0) as u8;
+                s.controller.radial_mode = all[usize::from(next(i, all.len() as u8))];
+            }
+            Opt::PadRadialStick => {
+                let all = gamepad::RadialStick::ALL;
+                let i = all
+                    .iter()
+                    .position(|k| *k == s.controller.radial_stick)
+                    .unwrap_or(0) as u8;
+                // An opener under the thumb that now selects goes unbound.
+                s.controller
+                    .set_radial_stick(all[usize::from(next(i, all.len() as u8))]);
+            }
+            _ => {}
+        }
+    }
+}
@@ -8,9 +8,88 @@ use horizon_hooks::pages as added;
 /// `selected_key` while a registered page's key waits (`selected_native_key`: page, row).
 pub(super) const PAGE_KEY: &str = "horizon.pageKey";

+#[cfg(test)]
+thread_local! {
+    /// A test's own pages, instead of the game's registered ones: each test runs on its thread.
+    static TEST_PAGES: std::cell::Cell<Option<&'static [&'static dyn added::Page]>> =
+        const { std::cell::Cell::new(None) };
+}
+
+/// The pages crates registered.
+fn registered() -> &'static [&'static dyn added::Page] {
+    #[cfg(test)]
+    if let Some(pages) = TEST_PAGES.get() {
+        return pages;
+    }
+    added::engine::all()
+}
+
 /// A registered page's title (a translation key).
 pub(super) fn title(page: usize) -> &'static str {
-    added::engine::all().get(page).map_or("", |p| p.title())
+    registered().get(page).map_or("", |p| p.title())
+}
+
+/// Row `r` of a registered page, as it is now.
+fn row(page: usize, r: usize) -> Option<added::Row> {
+    let mut rows = Vec::new();
+    registered().get(page)?.rows(&mut rows);
+    rows.into_iter().nth(r)
+}
+
+/// A registered page's slider ([`Opt::Page`]): its caption (a translation key).
+pub(super) fn slider_caption(page: usize, r: usize) -> &'static str {
+    match row(page, r) {
+        Some(added::Row::Slider { label, .. }) => label,
+        _ => "",
+    }
+}
+
+/// A registered page's slider: its position.
+pub(super) fn slider_kind(page: usize, r: usize) -> Kind {
+    match row(page, r) {
+        Some(added::Row::Slider { value, .. }) => Kind::Slider(value.clamp(0.0, 1.0)),
+        _ => Kind::Cycle,
+    }
+}
+
+/// A registered page's slider: the value its message shows after the caption.
+pub(super) fn slider_text(page: usize, r: usize) -> Text {
+    match row(page, r) {
+        Some(added::Row::Slider { text, .. }) => label_text(text),
+        _ => Text::empty(),
+    }
+}
+
+/// A registered page's slider moved.
+pub(super) fn slide(page: usize, r: usize, value: f32) {
+    if let Some(registered) = registered().get(page) {
+        registered.act(r, added::Act::Slide(value));
+    }
+}
+
+/// What a registered page's row says on hover.
+pub(super) fn tooltip(page: usize, r: usize) -> Option<Text> {
+    registered().get(page)?.tooltip(r).map(label_text)
+}
+
+/// What a button opening one of Horizon's pages says on hover.
+pub(super) fn horizon_page_tooltip(page: Page) -> Option<&'static str> {
+    Some(match page {
+        Page::Horizon => "horizon.pages.settings.tooltip",
+        Page::Studio => "horizon.pages.studio.tooltip",
+        Page::Graphics => "horizon.pages.graphics.tooltip",
+        Page::GraphicsAdvanced => "horizon.pages.graphics_advanced.tooltip",
+        Page::Controller => "horizon.pages.controller.tooltip",
+        Page::Extras => "horizon.pages.extras.tooltip",
+        Page::Pvp => "horizon.pages.pvp.tooltip",
+        Page::Agent => "horizon.pages.agent.tooltip",
+        Page::SplitProfiles => "horizon.pages.split_profiles.tooltip",
+        Page::ShaderPacks => "horizon.pages.shader_packs.tooltip",
+        Page::Mods => "horizon.pages.mods.tooltip",
+        Page::SplitSetup => "horizon.pages.split_setup.tooltip",
+        Page::Music => "horizon.pages.music.tooltip",
+        _ => return None,
+    })
 }

 fn label_text(label: added::Label) -> Text {
@@ -45,29 +124,22 @@ impl OptionsUi {
                Some(open("horizon.pages.open.studio", Page::Studio)),
            ),
            // No AI hides the AI Agent page and everything AI.
-            Row::Buttons(
-                self.extra_button(s, crate::extras::Item::DiscordPresence),
-                Some(if s.extras.no_ai {
-                    self.extra_button(s, crate::extras::Item::NoAi)
-                } else {
-                    open("horizon.pages.open.agent", Page::Agent)
-                }),
-            ),
-        ]
-        .into_iter()
-        .chain(
-            (!s.extras.no_ai)
-                .then(|| Row::Buttons(self.extra_button(s, crate::extras::Item::NoAi), None)),
-        )
-        .collect();
+            if s.extras.no_ai {
+                Row::Buttons(self.extra_button(s, crate::extras::Item::NoAi), None)
+            } else {
+                Row::Buttons(
+                    open("horizon.pages.open.agent", Page::Agent),
+                    Some(self.extra_button(s, crate::extras::Item::NoAi)),
+                )
+            },
+        ];
        self.added_entries(&mut rows);
        rows
    }

    /// The entries of the pages registered for Horizon Settings, two to a row like the engine's.
    fn added_entries(&self, rows: &mut Vec<Row>) {
-        let mut entries = self
-            .pages
+        let mut entries = registered()
            .iter()
            .enumerate()
            .filter(|(_, page)| page.place() == added::Place::HorizonSettings)
@@ -79,15 +151,43 @@ impl OptionsUi {

    /// A registered page's rows, asked of it each time the page is drawn.
    pub(super) fn added_rows(&self, page: usize) -> Vec<Row> {
-        let Some(registered) = self.pages.get(page) else {
+        let Some(registered) = registered().get(page) else {
            return Vec::new();
        };
        let mut rows = Vec::new();
        registered.rows(&mut rows);
-        rows.into_iter()
-            .enumerate()
-            .map(|(r, row)| self.added_row(page, r, row))
-            .collect()
+        let mut out = Vec::new();
+        // The row a half-width button started, waiting for the next to sit beside it.
+        let mut half_open = false;
+        for (r, row) in rows.into_iter().enumerate() {
+            match row {
+                // Wrapped as the engine's own notes; space is for pages drawn as a screen.
+                added::Row::Text { text, .. } => {
+                    out.extend(wrap(&text, 64).into_iter().map(Row::Note))
+                }
+                added::Row::Space(_) => continue,
+                added::Row::Button {
+                    label,
+                    active,
+                    half: true,
+                    ..
+                } => {
+                    let mut half = button(0.0, 0.0, 150.0, tr(label), Act::PageRow(page, r));
+                    if !active {
+                        half = inactive(half);
+                    }
+                    match out.last_mut() {
+                        Some(Row::Buttons(_, second @ None)) if half_open => *second = Some(half),
+                        _ => out.push(Row::Buttons(half, None)),
+                    }
+                    half_open = !half_open;
+                    continue;
+                }
+                row => out.push(self.added_row(page, r, row)),
+            }
+            half_open = false;
+        }
+        out
    }

    fn added_row(&self, page: usize, r: usize, row: added::Row) -> Row {
@@ -98,7 +198,11 @@ impl OptionsUi {
            added::Row::Note(text) => Row::Note(text),
            added::Row::Toggle { label, on } => wide(generic(label, on_off(on))),
            added::Row::Cycle { label, value } => wide(generic(label, label_text(value))),
-            added::Row::Button { label } => wide(tr(label)),
+            added::Row::Slider { .. } => Row::Big(Opt::Page(page, r)),
+            added::Row::Button { label, active, .. } => {
+                let wide = button(0.0, 0.0, 310.0, tr(label), act);
+                Row::Buttons(if active { wide } else { inactive(wide) }, None)
+            }
            added::Row::Key { label, key } => {
                let mut message = keybinds::display_name(&key);
                if self.selected_key == Some(PAGE_KEY)
@@ -120,7 +224,7 @@ impl OptionsUi {

    /// A registered page's row was pressed: a key row waits for a key, any other row hears it.
    pub(super) fn page_act(&mut self, page: usize, r: usize, shift: bool) -> Vec<Event> {
-        let Some(registered) = self.pages.get(page) else {
+        let Some(registered) = registered().get(page) else {
            return Vec::new();
        };
        let mut rows = Vec::new();
@@ -199,7 +303,7 @@ impl OptionsUi {
    ) -> Vec<Event> {
        let (i, k) = self.selected_native_key.take().unwrap_or_default();
        if name == PAGE_KEY {
-            if let Some(page) = self.pages.get(i) {
+            if let Some(page) = registered().get(i) {
                page.act(k, added::Act::Bind(value));
            }
            return vec![Event::Changed];
@@ -221,11 +325,12 @@ mod tests {
    use super::*;
    use std::sync::Mutex;

-    /// A page with a heading, a switch, a number that steps either way and a key.
+    /// A page with a heading, a switch, a number that steps either way, a key and a volume.
    struct Sample {
        on: Mutex<bool>,
        step: Mutex<i32>,
        key: Mutex<String>,
+        volume: Mutex<f32>,
    }

    impl added::Page for Sample {
@@ -252,6 +357,12 @@ mod tests {
                label: "test.sample.key",
                key: self.key.lock().unwrap().clone(),
            });
+            let volume = *self.volume.lock().unwrap();
+            rows.push(added::Row::Slider {
+                label: "test.sample.volume",
+                value: volume,
+                text: added::Label::Value(format!("{}%", (volume * 100.0).round())),
+            });
        }
        fn act(&self, row: usize, act: added::Act) {
            match (row, act) {
@@ -262,15 +373,20 @@ mod tests {
                (2, added::Act::Press) => *self.step.lock().unwrap() += 1,
                (2, added::Act::PressBack) => *self.step.lock().unwrap() -= 1,
                (3, added::Act::Bind(key)) => *self.key.lock().unwrap() = key,
+                (4, added::Act::Slide(v)) => *self.volume.lock().unwrap() = v,
                other => panic!("row and act the page doesn't expect: {other:?}"),
            }
        }
+        fn tooltip(&self, row: usize) -> Option<added::Label> {
+            (row == 1).then_some(added::Label::Key("test.sample.switch.tooltip"))
+        }
    }

    static SAMPLE: Sample = Sample {
        on: Mutex::new(false),
        step: Mutex::new(0),
        key: Mutex::new(String::new()),
+        volume: Mutex::new(0.0),
    };
    static PAGES: [&dyn added::Page; 1] = [&SAMPLE];

@@ -297,10 +413,8 @@ mod tests {
    #[test]
    fn a_registered_page_opens_from_horizon_settings_and_hears_its_rows() {
        let mut s = Settings::default();
-        let mut ui = OptionsUi {
-            pages: &PAGES,
-            ..OptionsUi::default()
-        };
+        TEST_PAGES.set(Some(&PAGES));
+        let mut ui = OptionsUi::default();
        ui.show(Page::Horizon);
        press(&mut ui, &mut s, Act::Push(Page::Added(0)), false);
        assert_eq!(ui.page(), Page::Added(0));
@@ -323,5 +437,133 @@ mod tests {
        assert_eq!(events, [Event::Changed]);
        assert_eq!(*SAMPLE.key.lock().unwrap(), "key.keyboard.z");
        assert_eq!(ui.selected_key, None);
+        // The volume is one of the screen's own sliders: dragged to its middle, then let go.
+        let size = (480.0, 240.0);
+        let (widgets, ..) = ui.layout(&s, size.0, size.1);
+        let slider = widgets
+            .iter()
+            .find(|w| {
+                matches!(
+                    w.kind,
+                    WKind::Slider {
+                        opt: Opt::Page(0, 4),
+                        ..
+                    }
+                )
+            })
+            .expect("the volume's slider");
+        let (x, y) = (slider.x + slider.w / 2.0, slider.y + 1.0);
+        ui.click(&mut s, &atlas, x, y, size, [480, 240], false, false);
+        let volume = *SAMPLE.volume.lock().unwrap();
+        assert!((0.45..0.55).contains(&volume), "{volume}");
+        assert!(ui.release().contains(&Event::Changed));
+        // The slider shows the page's value once let go.
+        let (widgets, ..) = ui.layout(&s, size.0, size.1);
+        let shown = widgets.iter().find_map(|w| match w.kind {
+            WKind::Slider {
+                opt: Opt::Page(0, 4),
+                value,
+                ..
+            } => Some(value),
+            _ => None,
+        });
+        assert_eq!(shown, Some(volume));
+        // The page's tooltip for its switch.
+        let switch = widgets
+            .iter()
+            .find(|w| {
+                matches!(
+                    &w.kind,
+                    WKind::Button {
+                        act: Act::PageRow(0, 1),
+                        ..
+                    }
+                )
+            })
+            .expect("the switch");
+        assert_eq!(
+            tooltip_text(&s, switch).map(|t| t.plain()),
+            Some(tr("test.sample.switch.tooltip").plain())
+        );
+    }
+
+    /// Text, a grey note, space, two half buttons (the second inactive) and a footer button.
+    struct Shaped(Mutex<Vec<usize>>);
+
+    impl added::Page for Shaped {
+        fn id(&self) -> &'static str {
+            "test.shaped"
+        }
+        fn title(&self) -> &'static str {
+            "test.shaped.title"
+        }
+        fn place(&self) -> added::Place {
+            added::Place::HorizonSettings
+        }
+        fn rows(&self, rows: &mut Vec<added::Row>) {
+            rows.push(added::Row::text("ABCDE-FGHIJ").groups());
+            rows.push(added::Row::text("grey").quiet());
+            rows.push(added::Row::Space(6));
+            rows.push(added::Row::button("test.shaped.copy").half());
+            rows.push(added::Row::button("test.shaped.stop").half().active(false));
+            rows.push(added::Row::button("test.shaped.help").footer());
+        }
+        fn act(&self, row: usize, _: added::Act) {
+            self.0.lock().unwrap().push(row);
+        }
+    }
+
+    static SHAPED: Shaped = Shaped(Mutex::new(Vec::new()));
+    static SHAPED_PAGES: [&dyn added::Page; 1] = [&SHAPED];
+
+    #[test]
+    fn half_buttons_share_a_row_and_an_inactive_one_is_never_pressed() {
+        let mut s = Settings::default();
+        TEST_PAGES.set(Some(&SHAPED_PAGES));
+        let ui = OptionsUi::default();
+        let rows = ui.added_rows(0);
+        // The two texts as notes (space shows nothing here), the halves on one row, the
+        // footer button below them (the settings shell has no footer of its own).
+        assert!(matches!(&rows[0], Row::Note(t) if t == "ABCDE-FGHIJ"));
+        assert!(matches!(&rows[1], Row::Note(t) if t == "grey"));
+        let Row::Buttons(copy, Some(stop)) = &rows[2] else {
+            panic!("the halves sit side by side: {:?}", rows.len());
+        };
+        assert_eq!((copy.w, stop.w), (150.0, 150.0));
+        assert!(matches!(&rows[3], Row::Buttons(help, None) if help.w == 310.0));
+        assert_eq!(rows.len(), 4);
+        let mut ui = ui;
+        ui.show(Page::Added(0));
+        press(&mut ui, &mut s, Act::PageRow(0, 3), false);
+        press(&mut ui, &mut s, Act::PageRow(0, 5), false);
+        let (widgets, ..) = ui.layout(&s, 480.0, 240.0);
+        let stop = widgets
+            .iter()
+            .find(|w| {
+                matches!(
+                    &w.kind,
+                    WKind::Button {
+                        act: Act::PageRow(0, 4),
+                        ..
+                    }
+                )
+            })
+            .expect("Stop is drawn");
+        let atlas = super::super::tests::atlas();
+        ui.click(
+            &mut s,
+            &atlas,
+            stop.x + 1.0,
+            stop.y + 1.0,
+            (480.0, 240.0),
+            [480, 240],
+            false,
+            false,
+        );
+        assert_eq!(
+            *SHAPED.0.lock().unwrap(),
+            [3, 5],
+            "the inactive half heard nothing"
+        );
    }
 }
@@ -0,0 +1,79 @@
+//! Polytone's custom colours (`horizon_polytone::colors`, `colors.json` or `color.properties`)
+//! as the engine's pack colours ([`crate::pack_palette::PackColors`]).
+use std::path::Path;
+
+use horizon_polytone::colors::PackColors;
+
+use crate::block_entity_render::DYES;
+use crate::pack_palette::{self, Environment};
+
+fn fluid(fog: horizon_polytone::colors::FluidFog) -> pack_palette::FluidFog {
+    pack_palette::FluidFog {
+        color: fog.color,
+        radius: fog.radius,
+        fade: fog.fade,
+    }
+}
+
+/// The colours of every namespace's file under the pack overlay at `root`.
+pub fn read(root: &Path) -> pack_palette::PackColors {
+    let colors = PackColors::read(root);
+    let by_dye = |f: &dyn Fn(&str) -> Option<u32>| std::array::from_fn(|i| f(DYES[i].0));
+    let env = colors.env;
+    pack_palette::PackColors {
+        dye_diffuse: by_dye(&|name| colors.dye(name, "diffuse")),
+        dye_text: by_dye(&|name| colors.dye(name, "text")),
+        sheep: by_dye(&|name| colors.sheep(name)),
+        redstone: std::array::from_fn(|i| colors.redstone(i as u8)),
+        effects: colors.effects(),
+        entity_shadows: colors.entity_shadows(),
+        xp_bar: colors.xp_bar(),
+        env: Environment {
+            powder_snow_fog: env.powder_snow_fog,
+            blindness_fog_distance: env.blindness_fog_distance,
+            darkness_fog_distance: env.darkness_fog_distance,
+            boss_fog_distance: env.boss_fog_distance,
+            water_fog_brightening: env.water_fog_brightening,
+            water_fog_brightening_time: env.water_fog_brightening_time,
+            horizon_height: env.horizon_height,
+        },
+        fluid_fog: pack_palette::FluidFogs {
+            water: colors.fluid_fog.water.map(fluid),
+            lava: colors.fluid_fog.lava.map(fluid),
+        },
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+    use crate::pack_palette::{diffuse, redstone, sheep_wool, text};
+
+    #[test]
+    fn a_pack_recolours_only_what_it_names() {
+        // Dyes no other test draws: the table is process-wide.
+        let dir = std::env::temp_dir().join(format!("pack-dyes-{}", std::process::id()));
+        let polytone = dir.join("assets/obs/polytone");
+        std::fs::create_dir_all(&polytone).unwrap();
+        std::fs::write(
+            polytone.join("colors.json"),
+            r#"{"dye": {"cyan": {"diffuse": "00ff00", "text": "0000ff"}}, "sheep": {"pink": "2040ff"}, "redstone": {"7": "0x123456"}}"#,
+        )
+        .unwrap();
+        crate::pack_palette::set(&read(&dir));
+        let (cyan, pink, purple) = (9, 6, 10);
+        assert_eq!(diffuse(cyan), 0x00ff00);
+        assert_eq!(text(cyan), 0x0000ff);
+        assert_eq!(sheep_wool(pink as u8), 0x2040ff);
+        // Wool reads vanilla's dye, not the pack's diffuse: 75% of 0x169C9C.
+        assert_eq!(sheep_wool(cyan as u8), 0x107575);
+        assert_eq!(diffuse(purple), 0x8932B8);
+        assert_eq!(text(purple), 0xA020F0);
+        assert_eq!((redstone(7), redstone(15)), (Some(0x123456), None));
+        crate::pack_palette::set(&Default::default());
+        assert_eq!(redstone(7), None);
+        assert_eq!(diffuse(cyan), 0x169C9C);
+        assert_eq!(sheep_wool(pink as u8), 0xB6687F);
+        std::fs::remove_dir_all(&dir).ok();
+    }
+}
@@ -0,0 +1,252 @@
+//! OptiFine custom skies (`horizon_optifine::sky`) on the engine's sky layers
+//! ([`crate::custom_sky`]): a pack's layers with their decoded textures, read once with the pack,
+//! and each frame's choice of layers, their brightness and rotation. A pack without
+//! `optifine/sky` has none, and the sky stays vanilla.
+
+use std::path::Path;
+
+use glam::{Mat4, Vec3};
+use horizon_optifine::sky::{Blend, Conditions, Now, Skies, SkyLayer, Transition};
+
+use crate::custom_sky::{self as engine, Draw, Image, SkyLayers, State};
+
+/// The pack's layers, by world, with one texture per layer (`images[i]` for the `i`th layer
+/// over all worlds, in `worlds` order).
+#[derive(Default)]
+pub struct CustomSky {
+    worlds: Vec<(i32, Vec<SkyLayer>)>,
+    pub images: Vec<Image>,
+}
+
+/// Textures past this many texels in all are left out (a skybox is a few megapixels at most).
+const TEXEL_BUDGET: u64 = 64 << 20;
+
+impl CustomSky {
+    /// The custom skies of the overlay at `root`. A layer whose texture does not decode is
+    /// dropped with a warning.
+    pub fn load(root: &Path) -> Self {
+        let skies = Skies::scan(root);
+        let mut out = Self::default();
+        let mut texels = 0u64;
+        for (world, sky) in skies.worlds {
+            let mut layers = Vec::new();
+            for layer in sky.layers {
+                match crate::hud::decode(&root.join(&layer.source)) {
+                    Ok((width, height, rgba))
+                        if texels + u64::from(width) * u64::from(height) <= TEXEL_BUDGET =>
+                    {
+                        texels += u64::from(width) * u64::from(height);
+                        out.images.push(Image {
+                            width,
+                            height,
+                            rgba,
+                        });
+                        layers.push(layer);
+                    }
+                    Ok(_) => log::warn!("{}: past the custom sky's texture budget", layer.source),
+                    Err(e) => log::warn!("{}: {e:#}", layer.source),
+                }
+            }
+            if !layers.is_empty() {
+                out.worlds.push((world, layers));
+            }
+        }
+        out
+    }
+
+    pub fn is_empty(&self) -> bool {
+        self.worlds.is_empty()
+    }
+}
+
+/// The engine's sky blend for OptiFine's.
+fn blend(blend: Blend) -> engine::Blend {
+    match blend {
+        Blend::Add => engine::Blend::Add,
+        Blend::Subtract => engine::Blend::Subtract,
+        Blend::Multiply => engine::Blend::Multiply,
+        Blend::Dodge => engine::Blend::Dodge,
+        Blend::Burn => engine::Blend::Burn,
+        Blend::Screen => engine::Blend::Screen,
+        Blend::Replace => engine::Blend::Replace,
+        Blend::Overlay => engine::Blend::Overlay,
+        Blend::Alpha => engine::Blend::Alpha,
+    }
+}
+
+impl SkyLayers for CustomSky {
+    fn images(&self) -> &[Image] {
+        &self.images
+    }
+
+    /// Whether `world` has layers (`0` the Overworld, `1` the End).
+    fn has(&self, world: i32) -> bool {
+        self.worlds.iter().any(|(w, _)| *w == world)
+    }
+
+    /// The layers whose conditions hold, eased over their `transition`, at the brightness of
+    /// their fade times.
+    fn draws(
+        &self,
+        world: i32,
+        conditions: &engine::Conditions,
+        sun_turns: f32,
+        seconds: f32,
+        state: &mut State,
+        out: &mut Vec<Draw>,
+    ) {
+        let conditions = &Conditions {
+            day_time: conditions.day_time,
+            weather: match conditions.weather {
+                engine::Weather::Clear => Now::Clear,
+                engine::Weather::Rain => Now::Rain,
+                engine::Weather::Thunder => Now::Thunder,
+            },
+            biome: conditions.biome,
+            y: conditions.y,
+        };
+        out.clear();
+        let mut first = 0;
+        let mut found = None;
+        for (w, layers) in &self.worlds {
+            if *w == world {
+                found = Some(layers);
+                break;
+            }
+            first += layers.len();
+        }
+        let Some(layers) = found else {
+            state.world = None;
+            return;
+        };
+        // A new world (or pack) starts each layer where its conditions put it: no fade in.
+        let snap = state.world != Some(world) || state.eased.len() != layers.len();
+        if snap {
+            state.world = Some(world);
+            state.eased.clear();
+            state.eased.resize(layers.len(), 0.0);
+        }
+        for (i, (layer, eased)) in layers.iter().zip(&mut state.eased).enumerate() {
+            let target = if layer.shows(conditions) { 1.0 } else { 0.0 };
+            let shown = if snap {
+                *eased = target;
+                target
+            } else {
+                let mut t = Transition { value: *eased };
+                *eased = t.step(target, seconds, layer.transition);
+                *eased
+            };
+            let brightness = shown * layer.brightness(conditions.day_time);
+            if brightness <= 0.0 {
+                continue;
+            }
+            let turns = layer.turns(conditions.day_time, sun_turns);
+            let rotation = if turns == 0.0 {
+                Mat4::IDENTITY
+            } else {
+                Mat4::from_axis_angle(Vec3::from_array(layer.axis), turns * std::f32::consts::TAU)
+            };
+            out.push(Draw {
+                image: (first + i) as u16,
+                blend: blend(layer.blend),
+                brightness,
+                rotation,
+            });
+        }
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+    use crate::custom_sky::{Conditions, Weather};
+
+    fn pack(files: &[(&str, &str)]) -> (std::path::PathBuf, CustomSky) {
+        let root = std::env::temp_dir().join(format!(
+            "horizon-custom-sky-{}-{}",
+            std::process::id(),
+            files.len()
+        ));
+        let _ = std::fs::remove_dir_all(&root);
+        let dir = root.join("assets/minecraft/optifine/sky/world0");
+        std::fs::create_dir_all(&dir).unwrap();
+        let png = {
+            let mut bytes = Vec::new();
+            let mut encoder = png::Encoder::new(&mut bytes, 6, 4);
+            encoder.set_color(png::ColorType::Rgba);
+            encoder.set_depth(png::BitDepth::Eight);
+            let mut writer = encoder.write_header().unwrap();
+            writer
+                .write_image_data(&[255, 0, 0, 255].repeat(24))
+                .unwrap();
+            writer.finish().unwrap();
+            bytes
+        };
+        for (name, text) in files {
+            std::fs::write(dir.join(format!("{name}.properties")), text).unwrap();
+            std::fs::write(dir.join(format!("{name}.png")), &png).unwrap();
+        }
+        let sky = CustomSky::load(&root);
+        (root, sky)
+    }
+
+    fn noon(biome: &str) -> Conditions<'_> {
+        Conditions {
+            day_time: 6000,
+            weather: Weather::Clear,
+            biome,
+            y: 64,
+        }
+    }
+
+    #[test]
+    fn layers_ease_in_at_a_biome_border_but_not_on_arrival() {
+        let (root, sky) = pack(&[
+            ("sky1", "biomes=desert\ntransition=2"),
+            ("sky2", "blend=alpha\nrotate=false"),
+        ]);
+        let _ = std::fs::remove_dir_all(root);
+        assert!(sky.has(0) && !sky.has(1));
+        assert_eq!(sky.images[0].width, 6);
+        let (mut state, mut out) = (State::default(), Vec::new());
+        sky.draws(
+            0,
+            &noon("minecraft:desert"),
+            0.0,
+            0.05,
+            &mut state,
+            &mut out,
+        );
+        assert_eq!(
+            out.iter().map(|d| d.brightness).collect::<Vec<_>>(),
+            [1.0, 1.0]
+        );
+        // Out of the desert: the first layer fades over its two seconds.
+        sky.draws(0, &noon("minecraft:plains"), 0.0, 0.5, &mut state, &mut out);
+        assert_eq!(out[0].brightness, 0.75);
+        assert_eq!(out[1].blend, engine::Blend::Alpha);
+        sky.draws(0, &noon("minecraft:plains"), 0.0, 2.0, &mut state, &mut out);
+        assert_eq!(out.len(), 1, "a dark layer is not drawn");
+        assert_eq!(out[0].image, 1);
+        // Into the End, which has no layers, and back: no fade.
+        sky.draws(1, &noon("minecraft:desert"), 0.0, 0.0, &mut state, &mut out);
+        assert!(out.is_empty());
+        sky.draws(0, &noon("minecraft:desert"), 0.0, 0.0, &mut state, &mut out);
+        assert_eq!(out.len(), 2);
+    }
+
+    #[test]
+    fn a_layer_turns_west_like_the_sun() {
+        let (root, sky) = pack(&[("sky1", "")]);
+        let _ = std::fs::remove_dir_all(root);
+        let (mut state, mut out) = (State::default(), Vec::new());
+        // A quarter turn after noon (sunset): the skybox's zenith has gone down to the west.
+        let c = Conditions {
+            day_time: 12000,
+            ..noon("minecraft:plains")
+        };
+        sky.draws(0, &c, 0.25, 0.0, &mut state, &mut out);
+        let up = out[0].rotation.transform_vector3(Vec3::Y);
+        assert!((up - Vec3::NEG_X).length() < 1e-5, "{up}");
+    }
+}
@@ -0,0 +1,146 @@
+//! Polytone's item modifiers' durability bar colours, on the engine's
+//! [`crate::pack_palette::ItemBars`].
+use std::path::Path;
+use std::sync::Arc;
+
+/// An item modifier's `bar_color` of the `damage` type: a row of colours picked by the stack's
+/// damage, the first pixel undamaged, the last at full damage (measured on the real mod).
+struct DamageBar {
+    targets: horizon_polytone::Targets,
+    row: Vec<u32>,
+}
+
+/// The packs' damage bars, the last read first.
+struct Bars(Vec<DamageBar>);
+
+impl crate::pack_palette::ItemBars for Bars {
+    fn color(&self, item: &str, damage: f32) -> Option<u32> {
+        let bar = self
+            .0
+            .iter()
+            .rev()
+            .find(|b| b.targets.matches(item, |_| false))?;
+        let last = (bar.row.len() - 1) as f32;
+        Some(bar.row[(damage.clamp(0.0, 1.0) * last).round() as usize])
+    }
+}
+
+/// Reads the packs' item modifiers' durability bar colours under a pack overlay root: an
+/// `<item>_bar.png` alone, or a json whose `bar_color` is `damage` with its `<name>_bar.png` (or
+/// `<name>.png`) beside it. Colormap ids and inline colormaps aren't read. `None` without any.
+pub fn read(root: &Path) -> Option<Arc<dyn crate::pack_palette::ItemBars>> {
+    let mut bars = Vec::new();
+    for namespace in std::fs::read_dir(root.join("assets"))
+        .into_iter()
+        .flatten()
+        .flatten()
+    {
+        let base = namespace.path().join("polytone/item_modifiers");
+        let mut stack = vec![base.clone()];
+        while let Some(dir) = stack.pop() {
+            for entry in std::fs::read_dir(&dir).into_iter().flatten().flatten() {
+                let path = entry.path();
+                if path.is_dir() {
+                    stack.push(path);
+                } else if let Some(bar) = item_bar(root, &base, &path) {
+                    bars.push(bar);
+                }
+            }
+        }
+    }
+    (!bars.is_empty()).then(|| Arc::new(Bars(bars)) as _)
+}
+
+fn item_bar(root: &Path, base: &Path, path: &Path) -> Option<DamageBar> {
+    let name = path.file_name()?.to_str()?;
+    let row = |png: &Path| {
+        let (width, _, rgba) = crate::sprites::read_rgba(png).ok()?;
+        let row: Vec<u32> = rgba[..width as usize * 4]
+            .as_chunks::<4>()
+            .0
+            .iter()
+            .map(|p| u32::from(p[0]) << 16 | u32::from(p[1]) << 8 | u32::from(p[2]))
+            .collect();
+        (!row.is_empty()).then_some(row)
+    };
+    if let Some(stem) = name.strip_suffix("_bar.png") {
+        // A json of the same name owns its png.
+        if path.with_file_name(format!("{stem}.json")).exists() {
+            return None;
+        }
+        let relative = path.parent()?.strip_prefix(base).ok()?.join(stem);
+        let namespace = base.parent()?.parent()?.file_name()?.to_str()?;
+        let id = format!("{namespace}:{}", relative.to_str()?.replace('\\', "/"));
+        let targets = horizon_polytone::Targets::parse(None, Some(&id)).ok()?;
+        return Some(DamageBar {
+            targets,
+            row: row(path)?,
+        });
+    }
+    let stem = name.strip_suffix(".json")?;
+    let json: serde_json::Value = horizon_world::json_file::read(path).ok()?;
+    if json.get("bar_color")?.as_str()? != "damage" {
+        return None;
+    }
+    let png = [format!("{stem}_bar.png"), format!("{stem}.png")]
+        .into_iter()
+        .map(|png| path.with_file_name(png))
+        .find(|png| png.exists())?;
+    let relative = path.strip_prefix(root).unwrap_or(path).to_string_lossy();
+    let implicit = horizon_polytone::implicit_id(&relative, "item_modifiers");
+    let targets =
+        horizon_polytone::Targets::parse(json.get("targets"), implicit.as_deref()).ok()?;
+    Some(DamageBar {
+        targets,
+        row: row(&png)?,
+    })
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    fn png_row(path: &Path, pixels: &[[u8; 3]]) {
+        std::fs::create_dir_all(path.parent().unwrap()).unwrap();
+        let file = std::fs::File::create(path).unwrap();
+        let mut encoder = png::Encoder::new(file, pixels.len() as u32, 1);
+        encoder.set_color(png::ColorType::Rgba);
+        let data: Vec<u8> = pixels
+            .iter()
+            .flat_map(|p| [p[0], p[1], p[2], 255])
+            .collect();
+        encoder
+            .write_header()
+            .unwrap()
+            .write_image_data(&data)
+            .unwrap();
+    }
+
+    #[test]
+    fn a_damage_bar_picks_its_pixel_by_the_stacks_damage() {
+        let dir = std::env::temp_dir().join(format!("pack-bars-{}", std::process::id()));
+        let modifiers = dir.join("assets/minecraft/polytone/item_modifiers");
+        let rgby = [[255, 0, 0], [0, 255, 0], [0, 0, 255], [255, 255, 0]];
+        png_row(&modifiers.join("diamond_pickaxe_bar.png"), &rgby);
+        std::fs::write(
+            modifiers.join("tools.json"),
+            r#"{"targets": ["minecraft:iron_axe"], "bar_color": "damage"}"#,
+        )
+        .unwrap();
+        png_row(&modifiers.join("tools_bar.png"), &[[1, 2, 3], [4, 5, 6]]);
+        let bars = read(&dir).unwrap();
+        // The real mod: damage 200 of 1561 shows the first pixel, 1400 the last.
+        assert_eq!(
+            bars.color("minecraft:diamond_pickaxe", 200.0 / 1561.0),
+            Some(0xFF0000)
+        );
+        assert_eq!(
+            bars.color("minecraft:diamond_pickaxe", 1400.0 / 1561.0),
+            Some(0xFFFF00)
+        );
+        assert_eq!(bars.color("minecraft:iron_axe", 0.9), Some(0x040506));
+        assert_eq!(bars.color("minecraft:diamond_shovel", 0.5), None);
+        assert!(read(&dir.join("none")).is_none());
+        std::fs::remove_dir_all(&dir).ok();
+    }
+}
@@ -0,0 +1,40 @@
+//! The resource pack formats vanilla doesn't read (OptiFine's, Polytone's) on the engine's
+//! extension points ([`crate::pack_hooks`]). This is platform code (docs/layers.md) kept in this
+//! crate until the platform's executable installs it: it uses only the crate's public API, so it
+//! moves to a platform crate unchanged, and nothing else in the crate names it.
+
+mod colors;
+mod custom_sky;
+mod item_bars;
+
+use std::path::Path;
+use std::sync::Arc;
+
+use crate::pack_hooks::PackFormats;
+
+/// OptiFine's and Polytone's formats.
+pub struct Formats;
+
+impl PackFormats for Formats {
+    fn colors(&self, root: &Path) -> Option<crate::pack_palette::PackColors> {
+        Some(colors::read(root))
+    }
+
+    fn emissive_suffix(&self, root: &Path) -> Option<String> {
+        Some(horizon_optifine::emissive::suffix(root))
+    }
+
+    fn custom_sky(&self, root: &Path) -> Option<Arc<dyn crate::custom_sky::SkyLayers>> {
+        let sky = custom_sky::CustomSky::load(root);
+        (!sky.is_empty()).then(|| Arc::new(sky) as _)
+    }
+
+    fn item_bars(&self, root: &Path) -> Option<Arc<dyn crate::pack_palette::ItemBars>> {
+        item_bars::read(root)
+    }
+}
+
+/// Installs these formats ([`crate::pack_hooks::install`]); the game does at startup.
+pub fn install() {
+    crate::pack_hooks::install(&Formats);
+}
@@ -0,0 +1,51 @@
+//! The engine's extension points for resource pack formats vanilla doesn't read (OptiFine's,
+//! Polytone's: platform code, docs/layers.md). The engine asks [`formats`] once per pack load and
+//! gets engine types back (tables, or an object it calls at most once a frame), never a format's
+//! own types. The platform installs its formats at startup ([`install`]); with none installed,
+//! packs load as vanilla reads them.
+
+use std::path::Path;
+use std::sync::{Arc, OnceLock};
+
+/// What the pack formats beyond vanilla's add to a pack. Each method reads one overlay of a pack
+/// (its folder at `root`); the default is "nothing in this format".
+pub trait PackFormats: Send + Sync {
+    /// The colours the overlay replaces where vanilla hardcodes them.
+    fn colors(&self, _root: &Path) -> Option<crate::pack_palette::PackColors> {
+        None
+    }
+
+    /// The name ending of the overlay's emissive textures (`stone_e.png` beside `stone.png`),
+    /// if its format has them.
+    fn emissive_suffix(&self, _root: &Path) -> Option<String> {
+        None
+    }
+
+    /// The sky layers the overlay draws over the vanilla sky, if it has any.
+    fn custom_sky(&self, _root: &Path) -> Option<Arc<dyn crate::custom_sky::SkyLayers>> {
+        None
+    }
+
+    /// The durability bar colours the overlay sets by item, if any.
+    fn item_bars(&self, _root: &Path) -> Option<Arc<dyn crate::pack_palette::ItemBars>> {
+        None
+    }
+}
+
+/// No format beyond vanilla's.
+struct Vanilla;
+
+impl PackFormats for Vanilla {}
+
+static FORMATS: OnceLock<&'static dyn PackFormats> = OnceLock::new();
+
+/// Installs the pack formats, before the first pack loads. The first call wins: later ones are
+/// ignored, so each test or probe that needs the formats may install them.
+pub fn install(formats: &'static dyn PackFormats) {
+    let _ = FORMATS.set(formats);
+}
+
+/// The installed pack formats, or vanilla's alone.
+pub fn formats() -> &'static dyn PackFormats {
+    FORMATS.get().copied().unwrap_or(&Vanilla)
+}
@@ -1,14 +1,106 @@
-//! Polytone's dye, sheep and redstone colours (`dye.<name>.diffuse|text`, `sheep.<name>`,
-//! `redstone.<power>`), for drawing only: the pack recolours collars, tropical fish, banners, wool,
-//! sign text and redstone wire and dust, while gameplay (crafting, item data, the beacon) keeps
-//! vanilla's `DyeColor`. Lock-free: the draw paths and the mesher's workers read it per face.
+//! The colours a pack replaces where vanilla hardcodes them (Polytone's `colors.json`, read by the
+//! platform's pack formats, [`crate::pack_hooks`]): dye, sheep and redstone colours, for drawing
+//! only (the pack recolours collars, tropical fish, banners, wool, sign text and redstone wire and
+//! dust, while gameplay keeps vanilla's `DyeColor`), mob effect colours, the experience number's,
+//! entity shadows, the effect fogs' settings and durability bar colours. Lock-free: the draw paths
+//! and the mesher's workers read the dye, sheep and redstone tables per face.
 use std::path::Path;
-use std::sync::RwLock;
 use std::sync::atomic::{AtomicU64, Ordering::Relaxed};
+use std::sync::{Arc, RwLock};

 use crate::block_entity_render::DYES;
 use crate::signs::DYE_TEXT;
-use horizon_polytone::colors::PackColors;
+
+/// The fog settings vanilla hardcodes, as the packs set them (vanilla's by default).
+#[derive(Clone, Copy, Debug, PartialEq)]
+pub struct Environment {
+    /// The fog colour inside powder snow (RGB).
+    pub powder_snow_fog: Option<u32>,
+    /// The fog ends of Blindness (5), Darkness (15) and bosses that add world fog (96).
+    pub blindness_fog_distance: f32,
+    pub darkness_fog_distance: f32,
+    pub boss_fog_distance: f32,
+    /// How much the underwater fog colour washes out (1 vanilla, 0 none).
+    pub water_fog_brightening: f32,
+    /// The ticks under water it takes (vanilla's 600).
+    pub water_fog_brightening_time: f32,
+    /// Below it the sky draws its dark disc (vanilla's 63; flat worlds keep their floor).
+    pub horizon_height: f32,
+}
+
+impl Default for Environment {
+    fn default() -> Self {
+        Self {
+            powder_snow_fog: None,
+            blindness_fog_distance: 5.0,
+            darkness_fog_distance: 15.0,
+            boss_fog_distance: 96.0,
+            water_fog_brightening: 1.0,
+            water_fog_brightening_time: 600.0,
+            horizon_height: 63.0,
+        }
+    }
+}
+
+/// The packs' colours; `None` (and the defaults) where they keep vanilla's.
+#[derive(Clone, Debug, PartialEq)]
+pub struct PackColors {
+    /// By dye id (`DyeColor` order): `getTextureDiffuseColor`, `getTextColor`, the sheep's wool.
+    pub dye_diffuse: [Option<u32>; 16],
+    pub dye_text: [Option<u32>; 16],
+    pub sheep: [Option<u32>; 16],
+    /// `RedStoneWireBlock.COLORS` by power.
+    pub redstone: [Option<u32>; 16],
+    /// Mob effects' colours, by effect id without vanilla's namespace.
+    pub effects: Vec<(String, u32)>,
+    /// False hides every entity's round shadow, whatever the video option says.
+    pub entity_shadows: bool,
+    /// The experience level number's colour and outline.
+    pub xp_bar: [Option<u32>; 2],
+    /// The effect fogs' settings: the fog reads them every frame.
+    pub env: Environment,
+    /// The fog the packs' fluid modifiers give water and lava.
+    pub fluid_fog: FluidFogs,
+}
+
+/// A fluid modifier's fog: a flat colour (RGB), and the fog's radius and fade multipliers (1 is
+/// vanilla's).
+#[derive(Clone, Copy, Debug, PartialEq)]
+pub struct FluidFog {
+    pub color: Option<u32>,
+    pub radius: f32,
+    pub fade: f32,
+}
+
+/// The fog the packs' fluid modifiers give water and lava.
+#[derive(Clone, Copy, Debug, Default, PartialEq)]
+pub struct FluidFogs {
+    pub water: Option<FluidFog>,
+    pub lava: Option<FluidFog>,
+}
+
+impl Default for PackColors {
+    fn default() -> Self {
+        Self {
+            dye_diffuse: [None; 16],
+            dye_text: [None; 16],
+            sheep: [None; 16],
+            redstone: [None; 16],
+            effects: Vec::new(),
+            entity_shadows: true,
+            xp_bar: [None; 2],
+            env: Environment::default(),
+            fluid_fog: FluidFogs::default(),
+        }
+    }
+}
+
+impl PackColors {
+    /// Whether entities draw their round shadow, as far as the packs say.
+    pub fn entity_shadows(&self) -> bool {
+        self.entity_shadows
+    }
+}

 /// 0 is unset, else `1 << 32 | rgb`.
 static DIFFUSE: [AtomicU64; 16] = [const { AtomicU64::new(0) }; 16];
@@ -16,6 +108,30 @@ static TEXT: [AtomicU64; 16] = [const { AtomicU64::new(0) }; 16];
 static SHEEP: [AtomicU64; 16] = [const { AtomicU64::new(0) }; 16];
 static REDSTONE: [AtomicU64; 16] = [const { AtomicU64::new(0) }; 16];

+/// The colours of the pack overlay at `root`, from the installed pack formats; their dye, sheep
+/// and redstone colours go to the draw paths' tables ([`set`]).
+pub fn read(root: &Path) -> PackColors {
+    let formats = crate::pack_hooks::formats();
+    let colors = formats.colors(root).unwrap_or_default();
+    set(&colors);
+    *ITEM_BARS.write().unwrap_or_else(|e| e.into_inner()) = formats.item_bars(root);
+    colors
+}
+
+/// The packs' durability bar colours by item (Polytone's item modifiers' `bar_color`).
+pub trait ItemBars: Send + Sync {
+    /// The bar colour (RGB) of `item` at this damage (0 to 1), when a pack sets one.
+    fn color(&self, item: &str, damage: f32) -> Option<u32>;
+}
+
+static ITEM_BARS: RwLock<Option<Arc<dyn ItemBars>>> = RwLock::new(None);
+
+/// A pack's durability bar colour (RGB) for an item at this damage (0 to 1).
+pub fn item_bar_color(item: &str, damage: f32) -> Option<u32> {
+    let bars = ITEM_BARS.read().unwrap_or_else(|e| e.into_inner());
+    bars.as_ref()?.color(item, damage)
+}
+
 /// Takes the colours of the packs just loaded (vanilla's where they set none).
 pub fn set(colors: &PackColors) {
    let store = |table: &[AtomicU64; 16], i: usize, color: Option<u32>| {
@@ -24,129 +140,39 @@ pub fn set(colors: &PackColors) {
            Relaxed,
        );
    };
-    for (i, (name, _)) in DYES.iter().enumerate() {
-        store(&DIFFUSE, i, colors.dye(name, "diffuse"));
-        store(&TEXT, i, colors.dye(name, "text"));
-        store(&SHEEP, i, colors.sheep(name));
-        store(&REDSTONE, i, colors.redstone(i as u8));
+    for i in 0..16 {
+        store(&DIFFUSE, i, colors.dye_diffuse[i]);
+        store(&TEXT, i, colors.dye_text[i]);
+        store(&SHEEP, i, colors.sheep[i]);
+        store(&REDSTONE, i, colors.redstone[i]);
    }
 }

-/// An item modifier's `bar_color` of the `damage` type: a row of colours picked by the stack's
-/// damage, the first pixel undamaged, the last at full damage (measured on the real mod).
-struct DamageBar {
-    targets: horizon_polytone::Targets,
-    row: Vec<u32>,
-}
-static ITEM_BARS: RwLock<Vec<DamageBar>> = RwLock::new(Vec::new());
-
-/// Reads the packs' item modifiers' durability bar colours under a pack overlay root: an
-/// `<item>_bar.png` alone, or a json whose `bar_color` is `damage` with its `<name>_bar.png` (or
-/// `<name>.png`) beside it. Colormap ids and inline colormaps aren't read.
-pub fn set_item_bars(root: &Path) {
-    let mut bars = Vec::new();
-    for namespace in std::fs::read_dir(root.join("assets"))
-        .into_iter()
-        .flatten()
-        .flatten()
-    {
-        let base = namespace.path().join("polytone/item_modifiers");
-        let mut stack = vec![base.clone()];
-        while let Some(dir) = stack.pop() {
-            for entry in std::fs::read_dir(&dir).into_iter().flatten().flatten() {
-                let path = entry.path();
-                if path.is_dir() {
-                    stack.push(path);
-                } else if let Some(bar) = item_bar(root, &base, &path) {
-                    bars.push(bar);
-                }
-            }
-        }
-    }
-    *ITEM_BARS.write().unwrap_or_else(|e| e.into_inner()) = bars;
-}
-
-fn item_bar(root: &Path, base: &Path, path: &Path) -> Option<DamageBar> {
-    let name = path.file_name()?.to_str()?;
-    let row = |png: &Path| {
-        let (width, _, rgba) = crate::sprites::read_rgba(png).ok()?;
-        let row: Vec<u32> = rgba[..width as usize * 4]
-            .as_chunks::<4>()
-            .0
-            .iter()
-            .map(|p| u32::from(p[0]) << 16 | u32::from(p[1]) << 8 | u32::from(p[2]))
-            .collect();
-        (!row.is_empty()).then_some(row)
-    };
-    if let Some(stem) = name.strip_suffix("_bar.png") {
-        // A json of the same name owns its png.
-        if path.with_file_name(format!("{stem}.json")).exists() {
-            return None;
-        }
-        let relative = path.parent()?.strip_prefix(base).ok()?.join(stem);
-        let namespace = base.parent()?.parent()?.file_name()?.to_str()?;
-        let id = format!("{namespace}:{}", relative.to_str()?.replace('\\', "/"));
-        let targets = horizon_polytone::Targets::parse(None, Some(&id)).ok()?;
-        return Some(DamageBar {
-            targets,
-            row: row(path)?,
-        });
-    }
-    let stem = name.strip_suffix(".json")?;
-    let json: serde_json::Value = horizon_world::json_file::read(path).ok()?;
-    if json.get("bar_color")?.as_str()? != "damage" {
-        return None;
-    }
-    let png = [format!("{stem}_bar.png"), format!("{stem}.png")]
-        .into_iter()
-        .map(|png| path.with_file_name(png))
-        .find(|png| png.exists())?;
-    let relative = path.strip_prefix(root).unwrap_or(path).to_string_lossy();
-    let implicit = horizon_polytone::implicit_id(&relative, "item_modifiers");
-    let targets =
-        horizon_polytone::Targets::parse(json.get("targets"), implicit.as_deref()).ok()?;
-    Some(DamageBar {
-        targets,
-        row: row(&png)?,
-    })
-}
-
-/// A pack's durability bar colour (RGB) for an item at this damage (0 to 1).
-pub fn item_bar_color(item: &str, damage: f32) -> Option<u32> {
-    let bars = ITEM_BARS.read().unwrap_or_else(|e| e.into_inner());
-    let bar = bars
-        .iter()
-        .rev()
-        .find(|b| b.targets.matches(item, |_| false))?;
-    let last = (bar.row.len() - 1) as f32;
-    Some(bar.row[(damage.clamp(0.0, 1.0) * last).round() as usize])
-}
-
-fn read(table: &[AtomicU64; 16], i: usize) -> Option<u32> {
+fn get(table: &[AtomicU64; 16], i: usize) -> Option<u32> {
    let v = table[i & 15].load(Relaxed);
    (v != 0).then_some(v as u32)
 }

 /// `DyeColor.getTextureDiffuseColor` (RGB) as the packs draw it.
 pub fn diffuse(dye: usize) -> u32 {
-    read(&DIFFUSE, dye).unwrap_or(DYES[dye & 15].1)
+    get(&DIFFUSE, dye).unwrap_or(DYES[dye & 15].1)
 }

 /// `DyeColor.getTextColor` (RGB) as the packs draw it.
 pub fn text(dye: usize) -> u32 {
-    read(&TEXT, dye).unwrap_or(DYE_TEXT[dye & 15].1)
+    get(&TEXT, dye).unwrap_or(DYE_TEXT[dye & 15].1)
 }

 /// A pack's `RedStoneWireBlock.COLORS` entry for this power (RGB), when it sets one.
 pub fn redstone(power: u8) -> Option<u32> {
-    read(&REDSTONE, usize::from(power))
+    get(&REDSTONE, usize::from(power))
 }

 /// `ColorLerper.Type.SHEEP` wool colour: a pack's `sheep.<name>`, else white 0xE6E6E6 and the
 /// others 75% of vanilla's dye (a pack's `dye.*.diffuse` doesn't reach wool).
 pub fn sheep_wool(dye: u8) -> u32 {
    let i = usize::from(dye & 15);
-    if let Some(color) = read(&SHEEP, i) {
+    if let Some(color) = get(&SHEEP, i) {
        return color;
    }
    if i == 0 {
@@ -156,81 +182,3 @@ pub fn sheep_wool(dye: u8) -> u32 {
    let f = |c: u32| ((c as f32 * 0.75).floor() as u32).min(255);
    f(src >> 16 & 255) << 16 | f(src >> 8 & 255) << 8 | f(src & 255)
 }
-
-#[cfg(test)]
-mod tests {
-    use super::*;
-
-    #[test]
-    fn a_pack_recolours_only_what_it_names() {
-        // Dyes no other test draws: the table is process-wide.
-        let dir = std::env::temp_dir().join(format!("pack-dyes-{}", std::process::id()));
-        let polytone = dir.join("assets/obs/polytone");
-        std::fs::create_dir_all(&polytone).unwrap();
-        std::fs::write(
-            polytone.join("colors.json"),
-            r#"{"dye": {"cyan": {"diffuse": "00ff00", "text": "0000ff"}}, "sheep": {"pink": "2040ff"}, "redstone": {"7": "0x123456"}}"#,
-        )
-        .unwrap();
-        set(&PackColors::read(&dir));
-        let (cyan, pink, purple) = (9, 6, 10);
-        assert_eq!(diffuse(cyan), 0x00ff00);
-        assert_eq!(text(cyan), 0x0000ff);
-        assert_eq!(sheep_wool(pink as u8), 0x2040ff);
-        // Wool reads vanilla's dye, not the pack's diffuse: 75% of 0x169C9C.
-        assert_eq!(sheep_wool(cyan as u8), 0x107575);
-        assert_eq!(diffuse(purple), 0x8932B8);
-        assert_eq!(text(purple), 0xA020F0);
-        assert_eq!((redstone(7), redstone(15)), (Some(0x123456), None));
-        set(&PackColors::default());
-        assert_eq!(redstone(7), None);
-        assert_eq!(diffuse(cyan), 0x169C9C);
-        assert_eq!(sheep_wool(pink as u8), 0xB6687F);
-        std::fs::remove_dir_all(&dir).ok();
-    }
-
-    fn png_row(path: &Path, pixels: &[[u8; 3]]) {
-        std::fs::create_dir_all(path.parent().unwrap()).unwrap();
-        let file = std::fs::File::create(path).unwrap();
-        let mut encoder = png::Encoder::new(file, pixels.len() as u32, 1);
-        encoder.set_color(png::ColorType::Rgba);
-        let data: Vec<u8> = pixels
-            .iter()
-            .flat_map(|p| [p[0], p[1], p[2], 255])
-            .collect();
-        encoder
-            .write_header()
-            .unwrap()
-            .write_image_data(&data)
-            .unwrap();
-    }
-
-    #[test]
-    fn a_damage_bar_picks_its_pixel_by_the_stacks_damage() {
-        let dir = std::env::temp_dir().join(format!("pack-bars-{}", std::process::id()));
-        let modifiers = dir.join("assets/minecraft/polytone/item_modifiers");
-        let rgby = [[255, 0, 0], [0, 255, 0], [0, 0, 255], [255, 255, 0]];
-        png_row(&modifiers.join("diamond_pickaxe_bar.png"), &rgby);
-        std::fs::write(
-            modifiers.join("tools.json"),
-            r#"{"targets": ["minecraft:iron_axe"], "bar_color": "damage"}"#,
-        )
-        .unwrap();
-        png_row(&modifiers.join("tools_bar.png"), &[[1, 2, 3], [4, 5, 6]]);
-        set_item_bars(&dir);
-        // The real mod: damage 200 of 1561 shows the first pixel, 1400 the last.
-        assert_eq!(
-            item_bar_color("minecraft:diamond_pickaxe", 200.0 / 1561.0),
-            Some(0xFF0000)
-        );
-        assert_eq!(
-            item_bar_color("minecraft:diamond_pickaxe", 1400.0 / 1561.0),
-            Some(0xFFFF00)
-        );
-        assert_eq!(item_bar_color("minecraft:iron_axe", 0.9), Some(0x040506));
-        assert_eq!(item_bar_color("minecraft:diamond_shovel", 0.5), None);
-        set_item_bars(&dir.join("none"));
-        assert_eq!(item_bar_color("minecraft:diamond_pickaxe", 0.5), None);
-        std::fs::remove_dir_all(&dir).ok();
-    }
-}
@@ -31,6 +31,7 @@ mod native;
 pub mod polytone;
 mod polytone_gpu;
 mod polytone_model;
+mod spawn;
 pub use native::{ParticleController, ParticleUpdate};

 /// `ParticleOptions` with the parameters of the option classes used here.
@@ -1222,8 +1223,9 @@ pub struct ParticleLevel<'a> {
    pub collision: &'a BlockCollisionRegistry<'a>,
    /// Local player feet position and vertical velocity (`PlayerCloudParticle`).
    pub player: Option<([f64; 3], f64)>,
+    pub cached_chunk: std::cell::Cell<Option<((i32, i32), Option<&'a crate::chunk::Chunk>)>>,
 }
-impl ParticleLevel<'_> {
+impl<'a> ParticleLevel<'a> {
    fn collide(&self, bb: Aabb, d: [f64; 3]) -> [f64; 3] {
        let mut scene = SceneCollisions {
            world: self.world,
@@ -1231,9 +1233,6 @@ impl ParticleLevel<'_> {
            subject: None,
        };
        let movement = Vec3::new(d[0], d[1], d[2]);
-        // `Entity.collideBoundingBox(null, ...)`: no entity shapes, no border. Where no
-        // block of the swept box's cells can collide, it finds no shape and the
-        // movement stands, as the resolution below would return it.
        if scene.cells_without_collision(bb.expand_towards(movement)) {
            return d;
        }
@@ -1249,38 +1248,46 @@ impl ParticleLevel<'_> {
            p[2].floor() as i32,
        ]
    }
+    #[inline]
+    pub fn block(&self, x: i32, y: i32, z: i32) -> horizon_world::registry::BlockStateId {
+        let (cx, cz) = (x >> 4, z >> 4);
+        let chunk = match self.cached_chunk.get() {
+            Some(((ccx, ccz), c)) if ccx == cx && ccz == cz => c,
+            _ => {
+                let c = self.world.chunks.get(&(cx, cz)).map(|c| c.as_ref());
+                self.cached_chunk.set(Some(((cx, cz), c)));
+                c
+            }
+        };
+        chunk.map_or(self.world.air, |c| c.block(x & 15, y, z & 15))
+    }
    /// The fluid at a block and `FluidState.getHeight`.
    fn fluid(&self, b: [i32; 3]) -> (Fluid, f64) {
-        let s = self.facts.get(self.world.block(b[0], b[1], b[2]));
+        let s = self.facts.get(self.block(b[0], b[1], b[2]));
        if s.fluid == Fluid::None {
            return (Fluid::None, 0.0);
        }
-        let above = self.facts.get(self.world.block(b[0], b[1] + 1, b[2]));
-        let height = if above.fluid == s.fluid {
+        let above = self.facts.get(self.block(b[0], b[1] + 1, b[2]));
+        let h = if above.fluid == s.fluid {
            1.0
        } else {
            f64::from(s.fluid_level) / 9.0
        };
-        (s.fluid, height)
+        (s.fluid, h)
    }
    /// The fluid at a block and whether it is a source (`FluidState.isSource`).
    pub(crate) fn fluid_source(&self, b: [i32; 3]) -> (Fluid, bool) {
-        let s = self.facts.get(self.world.block(b[0], b[1], b[2]));
+        let s = self.facts.get(self.block(b[0], b[1], b[2]));
        (s.fluid, s.fluid_level == 8 && !s.fluid_falling)
    }
    /// `getCollisionShape(...).max(Y, x, z)` for cached shapes.
    fn collision_top(&self, b: [i32; 3], fx: f64, fz: f64) -> f64 {
-        let state = self.world.block(b[0], b[1], b[2]);
+        let state = self.block(b[0], b[1], b[2]);
        match self.collision.cached_shapes().cached_shape(state) {
            Ok(Some(shape)) if !shape.is_empty() => shape.max_at(Axis::Y, fx, fz),
            Ok(Some(_)) => 0.0,
-            _ => {
-                if self.facts.get(state).full_collision {
-                    1.0
-                } else {
-                    0.0
-                }
-            }
+            _ if self.facts.get(state).full_collision => 1.0,
+            _ => 0.0,
        }
    }
 }
@@ -2020,73 +2027,6 @@ impl ParticleEngine {
            (eye[0] - pos[0]).powi(2) + (eye[1] - pos[1]).powi(2) + (eye[2] - pos[2]).powi(2) <= 9.0
        })
    }
-    /// `ClientPacketListener.handleParticleEvent` for `ServerLevel.sendParticles`.
-    pub fn send_particles(
-        &mut self,
-        options: &ParticleOptions,
-        at: [f64; 3],
-        spread: [f64; 3],
-        speed: f64,
-        count: u32,
-    ) {
-        if count == 0 {
-            let v = [speed * spread[0], speed * spread[1], speed * spread[2]];
-            self.add(options, at, v);
-            return;
-        }
-        for _ in 0..count {
-            let r = &mut self.random;
-            let p = [
-                at[0] + r.next_gaussian() * spread[0],
-                at[1] + r.next_gaussian() * spread[1],
-                at[2] + r.next_gaussian() * spread[2],
-            ];
-            let v = [
-                r.next_gaussian() * speed,
-                r.next_gaussian() * speed,
-                r.next_gaussian() * speed,
-            ];
-            self.add(options, p, v);
-        }
-    }
-    /// `ParticleEngine.createParticle`: always spawned, but `ParticleEngine.add`
-    /// drops a spore blossom air particle once `ParticleLimit.SPORE_BLOSSOM` is full.
-    pub fn create(&mut self, options: &ParticleOptions, p: [f64; 3], v: [f64; 3]) {
-        if let Some(requests) = &mut self.created_requests {
-            requests.push((options.clone(), p, v));
-            return;
-        }
-        let seed = self.seeds.next_long();
-        if let Some(mut particle) = self.make(options, p, v, seed) {
-            *self.made.entry(options.ty.name()).or_default() += 1;
-            // Resource packs' Polytone particle modifiers (#11486), once as it spawns.
-            if let Some(registry) = &self.polytone
-                && registry.modifies_particles()
-            {
-                let id = match &options.mod_particle {
-                    Some(name) => name.clone(),
-                    None => format!("minecraft:{}", options.ty.name()),
-                };
-                polytone::modify(registry, &id, options.source.as_deref(), &mut particle);
-            }
-            // The provider has drawn, so rejecting here keeps vanilla's RNG order.
-            // shortcut: counts live plus queued particles by scanning instead of
-            // vanilla's counted map; use a counter if spore spawning shows in profiles.
-            if particle.ty == ParticleType::SporeBlossomAir
-                && self.particles.len() + self.pending.len() >= SPORE_BLOSSOM_LIMIT
-                && self
-                    .particles
-                    .iter()
-                    .chain(self.pending.iter())
-                    .filter(|q| q.ty == ParticleType::SporeBlossomAir)
-                    .count()
-                    >= SPORE_BLOSSOM_LIMIT
-            {
-                return;
-            }
-            self.pending.push(particle);
-        }
-    }
    /// How many particles of each type were made so far.
    pub fn made(&self) -> &std::collections::BTreeMap<&'static str, u64> {
        &self.made
@@ -4052,15 +3992,12 @@ impl ParticleEngine {
            }
            Behaviour::Lava => {
                p.base_tick(level);
-                if !p.removed {
-                    let odds = p.age as f32 / p.lifetime as f32;
-                    if p.random.next_float() > odds {
-                        self.add(
-                            &ParticleOptions::simple(ParticleType::Smoke),
-                            p.position,
-                            p.velocity,
-                        );
-                    }
+                if !p.removed && p.random.next_float() > p.age as f32 / p.lifetime as f32 {
+                    self.add(
+                        &ParticleOptions::simple(ParticleType::Smoke),
+                        p.position,
+                        p.velocity,
+                    );
                }
            }
            Behaviour::Crit => {
@@ -4144,9 +4081,7 @@ impl ParticleEngine {
                    *c *= f64::from(0.98f32);
                }
                if p.on_ground {
-                    if p.random.next_float() < 0.5 {
-                        p.removed = true;
-                    }
+                    p.removed |= p.random.next_float() < 0.5;
                    p.velocity[0] *= f64::from(0.7f32);
                    p.velocity[2] *= f64::from(0.7f32);
                }
@@ -4186,13 +4121,10 @@ impl ParticleEngine {
            } => {
                p.base_tick(level);
                let (fluid, source) = level.fluid_source(ParticleLevel::block_at(p.position));
-                if !(p.removed || (fluid == Fluid::Water && source)) {
-                    p.removed = true;
-                }
-                if !p.removed && p.position[1] >= y_end {
-                    p.removed = true;
-                }
-                if !p.removed && p.position[1] <= y_prev {
+                if !(fluid == Fluid::Water && source)
+                    || p.position[1] >= y_end
+                    || p.position[1] <= y_prev
+                {
                    p.removed = true;
                }
                // randomHorizontalWiggling, then a second, horizontal move.
@@ -4216,9 +4148,8 @@ impl ParticleEngine {
                p.base_tick(level);
                self.sprite_from_age(p);
                if p.age as f32 > fade_start {
-                    let frames_since_fade_out_start = p.age as f32 - fade_start;
                    p.rgba[3] =
-                        (p.lifetime as f32 - frames_since_fade_out_start) / p.lifetime as f32;
+                        (p.lifetime as f32 - (p.age as f32 - fade_start)) / p.lifetime as f32;
                }
            }
            Behaviour::NoxiousGasCloud => {
@@ -4682,7 +4613,7 @@ impl ParticleEngine {
                    self.sprite_from_age(p);
                    half(p);
                    let b = ParticleLevel::block_at(p.position);
-                    if level.facts.is_air(level.world.block(b[0], b[1], b[2])) {
+                    if level.facts.is_air(level.block(b[0], b[1], b[2])) {
                        p.velocity[1] -= f64::from(0.0074f32);
                    }
                }
@@ -4690,7 +4621,7 @@ impl ParticleEngine {
            Behaviour::Firefly => {
                p.base_tick(level);
                let b = ParticleLevel::block_at(p.position);
-                if !level.facts.is_air(level.world.block(b[0], b[1], b[2])) {
+                if !level.facts.is_air(level.block(b[0], b[1], b[2])) {
                    p.removed = true;
                } else {
                    p.rgba[3] = fade_amount(p.lifetime_progress(p.age as f32), 0.3, 0.5);
@@ -5154,11 +5085,12 @@ fn hdr_tier(ty: ParticleType) -> u8 {
 }
 /// `Particle.LifetimeAlpha.currentAlphaForAge`.
 fn lifetime_alpha(a: [f32; 4], age: i32, lifetime: i32, partial: f32) -> f32 {
-    if (a[0] - a[1]).abs() < 1.0e-5 {
-        return a[0];
-    }
    let t = ((age as f32 + partial) / lifetime as f32 - a[2]) / (a[3] - a[2]);
-    a[0] + (a[1] - a[0]) * t.clamp(0.0, 1.0)
+    if (a[0] - a[1]).abs() < 1.0e-5 {
+        a[0]
+    } else {
+        a[0] + (a[1] - a[0]) * t.clamp(0.0, 1.0)
+    }
 }

 struct Starter {
@@ -5589,6 +5521,7 @@ mod tests {
            facts: &facts,
            collision: &collision,
            player: None,
+            cached_chunk: std::cell::Cell::new(None),
        };
        let mut engine = ParticleEngine::new(Path::new(""), &HashMap::new(), &HashSet::new());
        engine.set_sprites.push(vec![10, 11, 12]);
@@ -5680,6 +5613,7 @@ mod tests {
            facts: &facts,
            collision: &collision,
            player: None,
+            cached_chunk: std::cell::Cell::new(None),
        };
        let mut engine = ParticleEngine::new(Path::new(""), &HashMap::new(), &HashSet::new());
        let mut particle = Particle::blank(ParticleType::Smoke, [0.0; 3]);
@@ -124,6 +124,7 @@ mod tests {
            facts: &facts,
            collision: &collision,
            player: None,
+            cached_chunk: std::cell::Cell::new(None),
        };
        let mut e = engine();
        let mut p = e
@@ -490,14 +490,14 @@ enum Subject<'a> {
 }

 /// What one expression runs against: its subject, the frame and the level.
-struct Ctx<'a> {
+struct Ctx<'a, 'l> {
    subject: Subject<'a>,
    random: &'a mut LegacyRandom,
    custom: &'a mut f64,
    customs: &'a mut BTreeMap<String, f64>,
    frame: &'a Frame,
    registry: &'a Registry,
-    level: Option<&'a ParticleLevel<'a>>,
+    level: Option<&'a ParticleLevel<'l>>,
    blocks: Vec<[i32; 3]>,
 }

@@ -515,7 +515,7 @@ fn axis(name: &str) -> usize {
    usize::from(name.as_bytes()[0] - b'x')
 }

-impl Ctx<'_> {
+impl Ctx<'_, '_> {
    fn position(&self) -> [f64; 3] {
        match &self.subject {
            Subject::Particle(p) => p.position,
@@ -683,7 +683,7 @@ impl Ctx<'_> {
    }
 }

-impl Host for Ctx<'_> {
+impl Host for Ctx<'_, '_> {
    fn root(&mut self, root: Root) -> V {
        match root {
            Root::Object => V::Object(SELF),
@@ -801,6 +801,26 @@ impl Host for Ctx<'_> {
            _ => Err(format!("{name} is not available here")),
        }
    }
+
+    /// A particle's own fields, as `particle_method` answers them.
+    fn field(&mut self, root: Root, field: horizon_polytone::expr::Field) -> Option<V> {
+        use horizon_polytone::expr::Field as F;
+        let Subject::Particle(p) = &self.subject else {
+            return None;
+        };
+        if root != Root::Object {
+            return None;
+        }
+        Some(V::Num(match field {
+            F::Age => f64::from(p.age),
+            F::Life => f64::from(p.lifetime),
+            F::Custom => *self.custom,
+            F::X => p.position[0],
+            F::Y => p.position[1],
+            F::Z => p.position[2],
+            F::Temperature | F::Downfall => return None,
+        }))
+    }
 }

 fn eval(program: &Program, ctx: &mut Ctx) -> Option<f64> {
@@ -1662,6 +1682,7 @@ mod tests {
            facts: &scene.facts,
            collision: &scene.collision,
            player: None,
+            cached_chunk: std::cell::Cell::new(None),
        };
        let mut engine = engine(Registry::read(&root, Default::default(), blocks));
        // Air has no emitters; the torch fires its first emitter only.
@@ -1701,6 +1722,7 @@ mod tests {
            facts: &scene.facts,
            collision: &scene.collision,
            player: None,
+            cached_chunk: std::cell::Cell::new(None),
        };
        let mut engine = engine(Registry::read(&root, Default::default(), blocks));
        engine.polytone_animate(&level, [1, 64, 1]);
@@ -1722,6 +1744,7 @@ mod tests {
            facts: &scene.facts,
            collision: &scene.collision,
            player: None,
+            cached_chunk: std::cell::Cell::new(None),
        };
        let mut engine = engine(Registry::read(&root, Default::default(), blocks));
        engine.polytone_animate(&level, [1, 64, 1]);
@@ -1767,6 +1790,7 @@ mod tests {
            facts: &scene.facts,
            collision: &scene.collision,
            player: None,
+            cached_chunk: std::cell::Cell::new(None),
        };
        let registry = Registry::read(&root, Default::default(), blocks);
        let frame = registry.frame.clone();
@@ -1820,6 +1844,7 @@ mod tests {
            facts: &scene.facts,
            collision: &scene.collision,
            player: None,
+            cached_chunk: std::cell::Cell::new(None),
        };
        let registry = Registry::read(&root, Default::default(), blocks);
        let mut engine = engine(registry);
@@ -1853,6 +1878,7 @@ mod tests {
            facts: &scene.facts,
            collision: &scene.collision,
            player: None,
+            cached_chunk: std::cell::Cell::new(None),
        };
        let mut engine = engine(Registry::read(&root, Default::default(), blocks));
        let rect = crate::hud::Rect {
@@ -1905,6 +1931,7 @@ mod tests {
            facts: &scene.facts,
            collision: &scene.collision,
            player: None,
+            cached_chunk: std::cell::Cell::new(None),
        };
        let mut engine = engine(Registry::read(&root, Default::default(), blocks));
        let rect = crate::hud::Rect {
@@ -1966,6 +1993,7 @@ mod tests {
            facts: &scene.facts,
            collision: &scene.collision,
            player: None,
+            cached_chunk: std::cell::Cell::new(None),
        };
        let mut engine = engine(Registry::read(&root, Default::default(), blocks));
        engine.polytone_entity(&level, "minecraft:player", [1.0, 70.0, 1.0]);
@@ -2014,6 +2042,7 @@ mod tests {
            facts: &scene.facts,
            collision: &scene.collision,
            player: None,
+            cached_chunk: std::cell::Cell::new(None),
        };
        let mut engine = engine(Registry::read(&root, Default::default(), blocks));
        let rect = crate::hud::Rect {
@@ -2080,6 +2109,7 @@ mod tests {
            facts: &scene.facts,
            collision: &scene.collision,
            player: None,
+            cached_chunk: std::cell::Cell::new(None),
        };
        let registry = Arc::new(Registry::read(&root, Default::default(), blocks));
        // The chunk's biome is id 0: plains, whose foliage is #336699.
@@ -2198,6 +2228,7 @@ mod tests {
            facts: &scene.facts,
            collision: &scene.collision,
            player: None,
+            cached_chunk: std::cell::Cell::new(None),
        };
        let mut engine = engine(Registry::read(&root, Default::default(), blocks));
        engine.polytone_entity(&level, "minecraft:player", [1.5, 70.0, 1.5]);
@@ -2276,6 +2307,7 @@ mod tests {
            facts: &scene.facts,
            collision: &scene.collision,
            player: None,
+            cached_chunk: std::cell::Cell::new(None),
        };
        let mut engine = engine(Registry::read(&root, Default::default(), blocks));
        // The test chunk's biome is the table's first: a cold one first, then a warm one.
@@ -0,0 +1,73 @@
+//! Where particles come into the engine: a server's particle packet and a single particle made
+//! where the game asks for one.
+use super::*;
+
+impl ParticleEngine {
+    /// `ClientPacketListener.handleParticleEvent` for `ServerLevel.sendParticles`.
+    pub fn send_particles(
+        &mut self,
+        options: &ParticleOptions,
+        at: [f64; 3],
+        spread: [f64; 3],
+        speed: f64,
+        count: u32,
+    ) {
+        if count == 0 {
+            let v = [speed * spread[0], speed * spread[1], speed * spread[2]];
+            self.add(options, at, v);
+            return;
+        }
+        for _ in 0..count {
+            let r = &mut self.random;
+            let p = [
+                at[0] + r.next_gaussian() * spread[0],
+                at[1] + r.next_gaussian() * spread[1],
+                at[2] + r.next_gaussian() * spread[2],
+            ];
+            let v = [
+                r.next_gaussian() * speed,
+                r.next_gaussian() * speed,
+                r.next_gaussian() * speed,
+            ];
+            self.add(options, p, v);
+        }
+    }
+    /// `ParticleEngine.createParticle`: always spawned, but `ParticleEngine.add`
+    /// drops a spore blossom air particle once `ParticleLimit.SPORE_BLOSSOM` is full.
+    pub fn create(&mut self, options: &ParticleOptions, p: [f64; 3], v: [f64; 3]) {
+        if let Some(requests) = &mut self.created_requests {
+            requests.push((options.clone(), p, v));
+            return;
+        }
+        let seed = self.seeds.next_long();
+        if let Some(mut particle) = self.make(options, p, v, seed) {
+            *self.made.entry(options.ty.name()).or_default() += 1;
+            // Resource packs' Polytone particle modifiers (#11486), once as it spawns.
+            if let Some(registry) = &self.polytone
+                && registry.modifies_particles()
+            {
+                let id = match &options.mod_particle {
+                    Some(name) => name.clone(),
+                    None => format!("minecraft:{}", options.ty.name()),
+                };
+                polytone::modify(registry, &id, options.source.as_deref(), &mut particle);
+            }
+            // The provider has drawn, so rejecting here keeps vanilla's RNG order.
+            // shortcut: counts live plus queued particles by scanning instead of
+            // vanilla's counted map; use a counter if spore spawning shows in profiles.
+            if particle.ty == ParticleType::SporeBlossomAir
+                && self.particles.len() + self.pending.len() >= SPORE_BLOSSOM_LIMIT
+                && self
+                    .particles
+                    .iter()
+                    .chain(self.pending.iter())
+                    .filter(|q| q.ty == ParticleType::SporeBlossomAir)
+                    .count()
+                    >= SPORE_BLOSSOM_LIMIT
+            {
+                return;
+            }
+            self.pending.push(particle);
+        }
+    }
+}
@@ -93,6 +93,7 @@ fn particle_tick_cost() {
        facts: &facts,
        collision: &collision,
        player: None,
+        cached_chunk: std::cell::Cell::new(None),
    };
    let ty = |name: &str| ParticleType::from_name(name).unwrap();
    let (fx, fy, fz) = (0.5, f64::from(FLOOR_Y + 5), 20.5);
@@ -7,7 +7,10 @@
 //! sections are immutable behind `Arc` and edited through `Arc::make_mut`, so
 //! a weak reference tells an edited or replaced section from the one the list
 //! was built from (see `random_tick_sections`), without keeping its blocks.
-use crate::{chunk::Section, fast_hash::FxHashMap};
+use crate::{
+    chunk::{Chunk, Section},
+    fast_hash::FxHashMap,
+};
 use std::sync::{Arc, Mutex, Weak};

 /// A section's POIs: the block index in the section (`y << 8 | z << 4 | x`)
@@ -18,13 +21,16 @@ struct Cached<T> {
    section: Weak<Section>,
    pois: SectionPois<T>,
 }
-/// Cached POI lists by section, `(chunk x, section index, chunk z)`.
+/// Cached POI lists by chunk column `(chunk x, chunk z)`, each by section
+/// index: a search through a column looks it up once.
 pub struct PoiSections<T> {
    sections: Mutex<Lists<T>>,
 }
 struct Lists<T> {
-    by_section: FxHashMap<(i32, i32, i32), Cached<T>>,
-    /// Size above which lists of sections no longer resident are dropped.
+    by_column: FxHashMap<(i32, i32), Vec<Option<Cached<T>>>>,
+    /// How many section lists are kept, and the count above which the lists
+    /// of sections no longer resident are dropped.
+    len: usize,
    prune_at: usize,
 }
 const MIN_PRUNE: usize = 4096;
@@ -32,27 +38,61 @@ impl<T> Default for PoiSections<T> {
    fn default() -> Self {
        Self {
            sections: Mutex::new(Lists {
-                by_section: FxHashMap::default(),
+                by_column: FxHashMap::default(),
+                len: 0,
                prune_at: MIN_PRUNE,
            }),
        }
    }
 }
-impl<T: Copy> PoiSections<T> {
-    /// The POIs of `section`, whose block states `kind` classifies. `kind`
-    /// must give the same answer for a state on every call.
-    pub fn get(
-        &self,
-        key: (i32, i32, i32),
-        section: &Arc<Section>,
-        mut kind: impl FnMut(u32) -> Option<T>,
-    ) -> SectionPois<T> {
-        let mut lists = self.sections.lock().unwrap_or_else(|e| e.into_inner());
-        if let Some(cached) = lists.by_section.get(&key)
-            && cached.section.as_ptr() == Arc::as_ptr(section)
-        {
-            return cached.pois.clone();
+impl<T: Copy> Lists<T> {
+    /// The column's lists, for sections up to `last`, after dropping the
+    /// lists of sections no longer resident if there are too many.
+    fn column(
+        &mut self,
+        column: (i32, i32),
+        last: usize,
+    ) -> (&mut [Option<Cached<T>>], &mut usize) {
+        if self.len >= self.prune_at {
+            self.prune();
        }
+        let lists = self.by_column.entry(column).or_default();
+        if lists.len() <= last {
+            lists.resize_with(last + 1, || None);
+        }
+        (lists, &mut self.len)
+    }
+
+    /// Drops the lists of sections no longer resident.
+    fn prune(&mut self) {
+        let mut len = 0;
+        self.by_column.retain(|_, lists| {
+            for c in lists.iter_mut() {
+                if c.as_ref().is_some_and(|c| c.section.strong_count() == 0) {
+                    *c = None;
+                }
+            }
+            let kept = lists.iter().filter(|c| c.is_some()).count();
+            len += kept;
+            kept > 0
+        });
+        self.len = len;
+        self.prune_at = (len * 2).max(MIN_PRUNE);
+    }
+}
+
+/// The POIs of `section` from `slot`, listed again (and kept there) unless
+/// `slot` was listed from this very section; `len` counts the slots filled.
+fn list<'a, T: Copy>(
+    slot: &'a mut Option<Cached<T>>,
+    len: &mut usize,
+    section: &Arc<Section>,
+    kind: &mut impl FnMut(u32) -> Option<T>,
+) -> &'a SectionPois<T> {
+    let fresh = slot
+        .as_ref()
+        .is_some_and(|c| c.section.as_ptr() == Arc::as_ptr(section));
+    if !fresh {
        let pois: SectionPois<T> = if section.blocks.maybe_has(|v| kind(v).is_some()) {
            let mut states = [0u32; 4096];
            section.unpack(&mut states);
@@ -64,18 +104,56 @@ impl<T: Copy> PoiSections<T> {
        } else {
            Arc::from([])
        };
-        if lists.by_section.len() >= lists.prune_at {
-            lists.by_section.retain(|_, c| c.section.strong_count() > 0);
-            lists.prune_at = (lists.by_section.len() * 2).max(MIN_PRUNE);
+        *len += usize::from(slot.is_none());
+        *slot = Some(Cached {
+            section: Arc::downgrade(section),
+            pois,
+        });
+    }
+    &slot.as_ref().expect("just listed").pois
+}
+
+impl<T: Copy> PoiSections<T> {
+    /// The POIs of `section`, the `key.1`-th section of the column
+    /// `(key.0, key.2)`, whose block states `kind` classifies. `kind` must give
+    /// the same answer for a state on every call.
+    pub fn get(
+        &self,
+        key: (i32, i32, i32),
+        section: &Arc<Section>,
+        mut kind: impl FnMut(u32) -> Option<T>,
+    ) -> SectionPois<T> {
+        let mut lists = self.sections.lock().unwrap_or_else(|e| e.into_inner());
+        let s = usize::try_from(key.1).expect("a section index");
+        let (column, len) = lists.column((key.0, key.2), s);
+        list(&mut column[s], len, section, &mut kind).clone()
+    }
+
+    /// The POIs of `chunk` from block Y `y0` to `y1`, its first section at
+    /// `min_y`, as [`Self::get`] gives them: each section that has any, with
+    /// the Y of its lowest blocks, in order, put in `out`. One lookup of the
+    /// column.
+    pub fn column(
+        &self,
+        chunk: &Chunk,
+        min_y: i32,
+        (y0, y1): (i32, i32),
+        mut kind: impl FnMut(u32) -> Option<T>,
+        out: &mut Vec<(i32, SectionPois<T>)>,
+    ) {
+        out.clear();
+        let (first, last) = ((y0 - min_y) >> 4, (y1 - min_y) >> 4);
+        if first > last {
+            return;
+        }
+        let mut lists = self.sections.lock().unwrap_or_else(|e| e.into_inner());
+        let (slots, len) = lists.column((chunk.x, chunk.z), last as usize);
+        for s in first as usize..=last as usize {
+            let pois = list(&mut slots[s], len, &chunk.sections[s], &mut kind);
+            if !pois.is_empty() {
+                out.push((min_y + s as i32 * 16, pois.clone()));
+            }
        }
-        lists.by_section.insert(
-            key,
-            Cached {
-                section: Arc::downgrade(section),
-                pois: pois.clone(),
-            },
-        );
-        pois
    }
 }

@@ -143,6 +221,48 @@ mod tests {
        assert!(index.get((0, 0, 0), &chunk.sections[0], kind).is_empty());
    }

+    /// A column gives each section's list as `get` does, the sections
+    /// without any left out, and keeps them until a section changes.
+    #[test]
+    fn a_column_gives_what_each_section_gives() {
+        let index = PoiSections::<u8>::default();
+        let kind = |v: u32| (v == 5).then_some(5);
+        let mut chunk = Arc::new(Chunk::empty(2, -3));
+        for (x, y, z) in [(1, MIN_Y + 2, 3), (4, MIN_Y + 40, 0), (0, MIN_Y + 41, 15)] {
+            Arc::make_mut(&mut chunk).set(x, y, z, 5);
+        }
+        let mut out = Vec::new();
+        index.column(&chunk, MIN_Y, (MIN_Y, MIN_Y + 63), kind, &mut out);
+        let bases: Vec<i32> = out.iter().map(|(base, _)| *base).collect();
+        assert_eq!(bases, [MIN_Y, MIN_Y + 32]);
+        for (base, pois) in &out {
+            let s = (base - MIN_Y) / 16;
+            let one = index.get((2, s, -3), &chunk.sections[s as usize], kind);
+            assert!(Arc::ptr_eq(pois, &one));
+        }
+        // Kept: no rescan.
+        index.column(
+            &chunk,
+            MIN_Y,
+            (MIN_Y, MIN_Y + 63),
+            |_| panic!("rescanned"),
+            &mut out,
+        );
+        assert_eq!(out.len(), 2);
+        // An edit lists that section again.
+        Arc::make_mut(&mut chunk).set(4, MIN_Y + 40, 0, 1);
+        let mut rescans = 0;
+        let counted = |v: u32| {
+            rescans += 1;
+            kind(v)
+        };
+        index.column(&chunk, MIN_Y, (MIN_Y + 20, MIN_Y + 63), counted, &mut out);
+        assert!(rescans > 0);
+        assert_eq!(out.len(), 1);
+        assert_eq!(out[0].0, MIN_Y + 32);
+        assert_eq!(&*out[0].1, &[(9 << 8 | 15 << 4, 5)]);
+    }
+
    #[test]
    fn unloaded_sections_are_dropped() {
        let index = PoiSections::<u8>::default();
@@ -153,7 +273,7 @@ mod tests {
            index.get((1, i, 0), &Arc::new(Section::default()), kind);
        }
        let lists = index.sections.lock().unwrap();
-        assert!(lists.by_section.len() <= 2);
-        assert!(lists.by_section.contains_key(&(0, 0, 0)));
+        assert!(lists.len <= 2);
+        assert!(lists.by_column[&(0, 0)][0].is_some());
    }
 }
@@ -4,7 +4,6 @@
 //! Horizon Settings > PvP & HUD. Every option is off by default, so the game looks like
 //! vanilla until the player changes one, and none of them shows anything vanilla doesn't
 //! already tell the player.
-use horizon_hooks::look::Look;

 /// Colours the PvP options pick from. `Inverted` is vanilla's crosshair blend: the colour
 /// under it, inverted.
@@ -264,6 +263,15 @@ impl ViewWeather {
        Self::ALL.into_iter().find(|c| c.name() == s)
    }
 }
+/// The day time this player sees with `fixed` set: the same day (the moon's phase follows the
+/// world's), at that time.
+pub fn view_day_time(world: i64, fixed: Option<ViewTime>) -> i64 {
+    match fixed {
+        Some(t) => world.div_euclid(24000) * 24000 + t.day_time(),
+        None => world,
+    }
+}
+
 /// The crosshair's look. Its defaults draw vanilla's: a 15-pixel cross, one pixel thick,
 /// inverting what is under it.
 #[derive(Clone, Copy, Debug, PartialEq, Eq)]
@@ -520,36 +528,24 @@ impl Hit {
    }
 }

+/// What the renderer reads of these options each frame (`FrameInputs::pvp`); the default is
+/// vanilla's look.
+#[derive(Clone, Copy, Debug, Default, PartialEq)]
+pub struct Frame {
+    /// The block outline's stroke ([`Outline::stroke`]).
+    pub outline: Option<(u32, f32)>,
+    /// The hurt overlay texel ([`Hit::texel`]), 0 for vanilla's.
+    pub hurt_texel: u32,
+    /// The glint's colour ([`Tweaks::glint_texel`]), 0 for vanilla's.
+    pub glint: u32,
+}
 impl Pvp {
-    /// What the engine reads of these options (`horizon_hooks::look`): all it draws differently.
-    /// Sets PvP & HUD's fields of `look`, the others' stay.
-    pub fn apply(&self, look: &mut Look) {
-        let (c, t) = (self.combat, self.tweaks);
-        look.legacy_pose = c.legacy;
-        look.hide_attack_indicator = c.legacy && !c.indicator;
-        look.mute_attack_sounds = c.legacy && c.sounds;
-        look.hide_attack_particles = c.legacy;
-        look.frame.outline = self.outline.stroke();
-        look.frame.hurt_texel = self.hit.texel();
-        look.frame.glint = t.glint_texel();
-        look.shield_size = t.shield_size;
-        look.totem_scale = f32::from(t.totem_size) / 100.0;
-        look.fire_lower = f32::from(t.fire_lower) / 100.0;
-        look.clear_lava = t.clear_lava;
-        look.clear_water = t.clear_water;
-        look.chat.timestamps = self.chat.timestamps;
-        look.chat.compact = self.chat.compact;
-        look.chat.copy = self.chat.copy;
-        look.chat.search = self.chat.search;
-        look.hide_effect_icons = self.hud.effects;
-        look.time_of_day = t.time.map(ViewTime::day_time);
-        look.weather = t.weather.map(ViewWeather::levels);
-    }
-    /// [`Pvp::apply`] on vanilla's look.
-    pub fn look(&self) -> Look {
-        let mut look = Look::default();
-        self.apply(&mut look);
-        look
+    pub fn frame(&self) -> Frame {
+        Frame {
+            outline: self.outline.stroke(),
+            hurt_texel: self.hit.texel(),
+            glint: self.tweaks.glint_texel(),
+        }
    }
 }

@@ -745,6 +741,15 @@ pub struct ChatOptions {
    /// Ctrl+F in the chat searches the chat's messages.
    pub search: bool,
 }
+impl ChatOptions {
+    /// What `chat::Chat` lays its lines out with.
+    pub fn qol(&self) -> crate::chat::ChatQol {
+        crate::chat::ChatQol {
+            timestamps: self.timestamps,
+            compact: self.compact,
+        }
+    }
+}

 /// Combat feel (`docs/pvp.md`): how fights look. Legacy draws them as 1.8.9 did; what the
 /// game sends to a server never changes, so a vanilla server and its anticheat see 26.3.
@@ -761,6 +766,21 @@ pub struct Combat {
    /// (`horizon_client::legacy_combat`). Never used as a client of a server.
    pub rules: bool,
 }
+impl Combat {
+    /// Whether this client leaves out sound `name` a server sent: under Legacy with its
+    /// sounds, the `entity.player.attack.*` family (strong, weak, crit, sweep, knockback,
+    /// nodamage), which 1.9 brought with the attack cooldown.
+    pub fn mutes_sound(&self, name: &str) -> bool {
+        let name = name.strip_prefix("minecraft:").unwrap_or(name);
+        self.legacy && self.sounds && name.starts_with("entity.player.attack.")
+    }
+    /// Whether this client leaves out particles of `ty` a server sent: under Legacy, the
+    /// sweep and the damage hearts, which 1.9 brought (1.8.9's hits show crits only).
+    pub fn hides_particle(&self, ty: crate::particles::ParticleType) -> bool {
+        use crate::particles::ParticleType as T;
+        self.legacy && matches!(ty, T::SweepAttack | T::DamageIndicator)
+    }
+}

 #[derive(Clone, Debug, PartialEq)]
 pub struct Pvp {
@@ -1687,6 +1707,18 @@ mod tests {
        assert_eq!(fresh.extras.pvp.tweaks.fire_lower, PRESET_FIRE_LOWER);
    }

+    #[test]
+    fn a_fixed_time_keeps_the_worlds_day() {
+        // Day 9 at 5000: the moon's phase (the day number) stays, the time of day is the chosen.
+        let world = 9 * 24000 + 5000;
+        assert_eq!(view_day_time(world, None), world);
+        assert_eq!(
+            view_day_time(world, Some(ViewTime::Midnight)),
+            9 * 24000 + 18000
+        );
+        assert_eq!(view_day_time(-100, Some(ViewTime::Noon)), -24000 + 6000);
+    }
+
    #[test]
    fn the_glint_colour_reaches_the_shaders_as_rgb_bytes() {
        let mut t = Tweaks::default();
@@ -1773,33 +1805,31 @@ mod tests {
        }
    }

-    /// Legacy leaves out what 1.9 added to a hit: its sounds only with the sounds option, the
-    /// sweep and hearts always; the indicator stays when kept. Modern changes nothing.
    #[test]
-    fn combat_feel_reaches_the_look() {
-        let mut pvp = Pvp::default();
-        assert_eq!(pvp.look(), Look::default(), "vanilla's look");
-        let strong = "minecraft:entity.player.attack.strong";
-        pvp.combat.legacy = true;
-        let look = pvp.look();
-        assert!(look.legacy_pose && look.hide_attack_particles && look.hide_attack_indicator);
-        assert!(!look.mutes_sound(strong), "only with the sounds option");
-        pvp.combat.sounds = true;
-        pvp.combat.indicator = true;
-        let look = pvp.look();
-        assert!(look.mutes_sound(strong) && !look.hide_attack_indicator);
-    }
-
-    #[test]
-    fn view_time_weather_and_sizes_reach_the_look() {
-        let mut pvp = Pvp::default();
-        pvp.tweaks.time = Some(ViewTime::Midnight);
-        pvp.tweaks.weather = Some(ViewWeather::Thunder);
-        pvp.tweaks.totem_size = 50;
-        pvp.tweaks.fire_lower = 40;
-        let look = pvp.look();
-        assert_eq!(look.day_time(9 * 24000 + 5000), 9 * 24000 + 18000);
-        assert_eq!(look.weather, Some((1.0, 1.0)));
-        assert_eq!((look.totem_scale, look.fire_lower), (0.5, 0.4));
+    fn legacy_leaves_out_what_1_9_added_to_a_hit() {
+        use crate::particles::ParticleType as T;
+        let modern = Combat::default();
+        let legacy = Combat {
+            legacy: true,
+            ..Combat::default()
+        };
+        let sounds = Combat {
+            sounds: true,
+            ..legacy
+        };
+        for name in [
+            "minecraft:entity.player.attack.strong",
+            "entity.player.attack.sweep",
+            "minecraft:entity.player.attack.nodamage",
+        ] {
+            assert!(sounds.mutes_sound(name), "{name}");
+            assert!(!legacy.mutes_sound(name), "only with the sounds option");
+            assert!(!modern.mutes_sound(name));
+        }
+        // 1.8.9 had the hurt sound: it stays.
+        assert!(!sounds.mutes_sound("minecraft:entity.player.hurt"));
+        assert!(legacy.hides_particle(T::SweepAttack) && legacy.hides_particle(T::DamageIndicator));
+        assert!(!legacy.hides_particle(T::Crit) && !legacy.hides_particle(T::EnchantedHit));
+        assert!(!modern.hides_particle(T::SweepAttack));
    }
 }
@@ -0,0 +1,844 @@
+//! The radial menu's pages in the controller settings (Horizon's own; `radial.rs` has their
+//! rules, `radial_overlay.rs` draws them in play), on the settings shell (`settings_shell`): a
+//! sheet per page with its eight slots, what changes the page, and what changes them all. A
+//! page's own name is typed on a small page of its own, [`NameEntry`].
+use crate::{
+    gamepad::{self, GlyphOf, MenuJob},
+    graphics_style::{self as style, BUTTON_H},
+    hud::{HudAtlas, HudBatch},
+    lang,
+    options_ui::{Event, Page},
+    pad_glyph::{Glyph, Glyphs},
+    radial::{self, Pages, RadialAction, SLOTS, Slot},
+    radial_overlay::{page_label, slot_caption},
+    settings::Settings,
+    settings_shell::{
+        self as shell, Binding, Capture, Group, Output, Reset, Row, Screen, Sheet, Shown, Value,
+    },
+    text::Text,
+    ui,
+};
+
+const TITLE: &str = "horizon.pages.controller_radial";
+const SLOTS_GROUP: &str = "horizon.radial.group.slots";
+const PAGE_GROUP: &str = "horizon.radial.group.page";
+const ALL_GROUP: &str = "horizon.radial.group.all";
+/// The opener's row binds the menu's own pad action, in place.
+const OPENER: &str = gamepad::RADIAL;
+
+/// A row of a page; `usize`s are the page and the slot.
+#[derive(Clone, Copy, Debug, PartialEq, Eq)]
+pub(crate) enum RadialRow {
+    Slot(usize, usize),
+    Rename(usize),
+    NewPage,
+    Delete(usize),
+    Reset,
+    Opener,
+}
+
+/// A slot's action, that it holds none, or that its action is missing.
+fn slot_label(slot: &Slot) -> String {
+    slot_caption(slot).unwrap_or_else(|| lang::get("horizon.radial.empty"))
+}
+
+/// What the slot after `slot` (before, `back`) holds: Empty between the last action and the first.
+/// A missing action steps as Empty does.
+fn step(slot: &Slot, back: bool) -> Slot {
+    let order: Vec<_> = std::iter::once(None)
+        .chain(RadialAction::ALL.map(Some))
+        .collect();
+    let at = order
+        .iter()
+        .position(|entry| *entry == slot.action())
+        .unwrap_or(0);
+    let next = if back { at + order.len() - 1 } else { at + 1 };
+    order[next % order.len()].into()
+}
+
+fn page_of(page: usize, pages: usize) -> String {
+    lang::tr("horizon.radial.page_of", &[&(page + 1), &pages])
+}
+
+/// The opener's row: a binding of the menu's own pad action, in place, on its button's art. Its
+/// strip says what stands in the way (no button, or one another action shares); while it waits,
+/// the shell says how to bind it.
+fn opener_row(s: &Settings, glyphs: Glyphs) -> Row<RadialRow> {
+    let pad = &s.controller;
+    // Through the player's glyphs, so a Nintendo pad going by its letters names its own button.
+    let glyph = Glyph::of(GlyphOf::Bound(OPENER), pad, glyphs);
+    let warning = match pad.binding(OPENER) {
+        None => Some(lang::get("horizon.radial.unbound")),
+        Some(_) => pad
+            .conflicts(OPENER)
+            .then(|| lang::get("horizon.radial.conflict")),
+    };
+    let binding = Binding {
+        capture: Capture::Pad(OPENER),
+        shown: Shown::Pad {
+            glyph,
+            cancel: Glyph::menu(MenuJob::Start, glyphs),
+        },
+        shared: Vec::new(),
+        // The default (D-pad Right) is refused with some sticks: no reset, only a new button.
+        reset: Reset::None,
+    };
+    let name = lang::get("horizon.radial.opener");
+    Row {
+        chosen: warning,
+        ..Row::new(RadialRow::Opener, name, Value::Binding(binding))
+            .about(lang::get(opener_about(pad.radial_stick)))
+    }
+}
+
+/// What the opener's row says it can be, with the stick that selects: never under that thumb.
+fn opener_about(stick: gamepad::RadialStick) -> &'static str {
+    match stick {
+        gamepad::RadialStick::Right => "horizon.radial.opener.about",
+        gamepad::RadialStick::Left => "horizon.radial.opener.about.left",
+        gamepad::RadialStick::Either => "horizon.radial.opener.about.either",
+    }
+}
+
+/// The page's rows: its slots, then what changes it.
+fn page_groups(pages: &Pages, page: usize) -> [Group<RadialRow>; 2] {
+    let slots = (0..SLOTS).map(|slot| {
+        let name = lang::get(&format!("horizon.radial.slot.{slot}"));
+        let cell = pages.page(page).slot(slot);
+        let value = Value::Choice(slot_label(cell));
+        let missing = match cell {
+            Slot::Missing(id) => Some(lang::tr("horizon.radial.missing.about", &[id])),
+            _ => None,
+        };
+        Row {
+            chosen: missing,
+            ..Row::new(RadialRow::Slot(page, slot), name, value)
+                .about(lang::get("horizon.radial.slot.about"))
+        }
+    });
+    let full = (pages.len() >= radial::MAX_PAGES)
+        .then(|| lang::tr("horizon.radial.new_page.full", &[&radial::MAX_PAGES]));
+    let last = (pages.len() <= 1).then(|| lang::get("horizon.radial.delete_page.last"));
+    let changes = vec![
+        Row::new(
+            RadialRow::Rename(page),
+            lang::get("horizon.radial.rename"),
+            Value::Press,
+        )
+        .about(lang::get("horizon.radial.rename.about")),
+        Row::new(
+            RadialRow::NewPage,
+            lang::get(radial::NEW_PAGE_NAME),
+            Value::Press,
+        )
+        .about(lang::get("horizon.radial.new_page.about"))
+        .blocked(full),
+        Row::new(
+            RadialRow::Delete(page),
+            lang::get("horizon.radial.delete_page"),
+            Value::Press,
+        )
+        .about(lang::get("horizon.radial.delete_page.about"))
+        .blocked(last),
+    ];
+    [
+        Group {
+            name: SLOTS_GROUP,
+            rows: slots.collect(),
+        },
+        Group {
+            name: PAGE_GROUP,
+            rows: changes,
+        },
+    ]
+}
+
+/// The screen's own state; the pages are the player's settings.
+#[derive(Default)]
+pub(crate) struct RadialScreen {
+    /// The buttons' names follow the controller in use: the options screen says which.
+    pub(crate) glyphs: Glyphs,
+    /// The page to show next: one just added, or where a deleted one was.
+    show: Option<usize>,
+    /// The page whose name is being typed, on its own page (`Page::ControllerRadialName`).
+    pub(crate) naming: Option<NameEntry>,
+    /// The slot (page, slot) whose list of actions opens next (`Page::ControllerRadialPick`).
+    pub(crate) picking: Option<(usize, usize)>,
+}
+
+impl RadialScreen {
+    /// The page the shell should show now, once.
+    pub(crate) fn take_shown(&mut self) -> Option<usize> {
+        self.show.take()
+    }
+}
+
+impl Screen for RadialScreen {
+    type Page = usize;
+    type Row = RadialRow;
+    fn title(&self) -> &'static str {
+        TITLE
+    }
+    /// The rows read the pages, the opener's button, the stick that selects and the glyphs it is
+    /// named with.
+    fn stamp(&self, s: &Settings) -> u64 {
+        let pad = &s.controller;
+        let opener = (pad.binding(OPENER), pad.conflicts(OPENER));
+        shell::stamp_of(&(&pad.radial, opener, pad.radial_stick, self.glyphs))
+    }
+    fn sheets(&self, s: &Settings) -> Vec<Sheet<usize, RadialRow>> {
+        let pages = &s.controller.radial;
+        let default = *pages == Pages::default();
+        let all = Group {
+            name: ALL_GROUP,
+            rows: vec![
+                Row::new(
+                    RadialRow::Reset,
+                    lang::get("horizon.radial.reset"),
+                    Value::Press,
+                )
+                .about(lang::get("horizon.radial.reset.about"))
+                .blocked(default.then(|| lang::get("horizon.radial.reset.default"))),
+                opener_row(s, self.glyphs),
+            ],
+        };
+        (0..pages.len())
+            .map(|page| {
+                let [slots, changes] = page_groups(pages, page);
+                let all = Group {
+                    name: all.name,
+                    rows: all.rows.clone(),
+                };
+                Sheet::new(
+                    page,
+                    page_label(pages.page(page)),
+                    page_of(page, pages.len()),
+                    vec![slots, changes, all],
+                )
+            })
+            .collect()
+    }
+    fn press(&mut self, s: &mut Settings, row: RadialRow, back: bool) -> Vec<Output> {
+        let pages = &mut s.controller.radial;
+        match row {
+            RadialRow::Slot(page, slot) => {
+                let next = step(pages.page(page).slot(slot), back);
+                pages.set_slot(page, slot, next);
+            }
+            RadialRow::Rename(page) => {
+                self.naming = Some(NameEntry::new(page, &page_label(pages.page(page))));
+                return vec![Output::Push(Page::ControllerRadialName)];
+            }
+            RadialRow::NewPage => self.show = pages.add(),
+            RadialRow::Delete(page) => {
+                pages.remove(page);
+                self.show = Some(pages.clamp(page));
+            }
+            RadialRow::Reset => {
+                *pages = Pages::default();
+                self.show = Some(0);
+            }
+            // The shell starts its wait (`gamepad::opener_refused` refused, Start cancels).
+            RadialRow::Opener => return Vec::new(),
+        }
+        vec![Output::Event(Event::Changed)]
+    }
+    /// A press on a slot opens the list of every action for it; Left and Right still step it.
+    fn choose(&mut self, _s: &mut Settings, row: RadialRow) -> Option<Vec<Output>> {
+        let RadialRow::Slot(page, slot) = row else {
+            return None;
+        };
+        self.picking = Some((page, slot));
+        Some(vec![Output::Push(Page::ControllerRadialPick)])
+    }
+    /// The wheel over a slot steps it, as a press does.
+    fn wheel_step(&mut self, s: &mut Settings, row: RadialRow, back: bool) -> Option<Vec<Output>> {
+        matches!(row, RadialRow::Slot(..)).then(|| self.press(s, row, back))
+    }
+    /// Undo is how a delete or a reset is taken back: they act at once.
+    fn undoes(&self) -> bool {
+        true
+    }
+    /// The pages, and the opener's button, which its row binds.
+    fn undo(&mut self, s: &mut Settings, before: &Settings) -> Vec<Output> {
+        s.controller.radial = before.controller.radial.clone();
+        s.controller.bind(OPENER, before.controller.binding(OPENER));
+        Vec::new()
+    }
+}
+
+const PICK_TITLE: &str = "horizon.radial.pick_title";
+const PICK_GROUP: &str = "horizon.radial.group.actions";
+
+/// A row of a slot's list: the line naming the slot, then Empty and every action.
+#[derive(Clone, Copy, Debug, PartialEq, Eq)]
+pub(crate) enum PickRow {
+    Slot,
+    Pick(Option<RadialAction>),
+}
+
+/// One slot's list of every action and Empty, on the settings shell: it names the slot, marks
+/// what the slot holds and opens on it; a press puts that in the slot and goes back.
+#[derive(Default)]
+pub(crate) struct PickScreen {
+    /// The page and the slot.
+    at: (usize, usize),
+    picked: bool,
+}
+
+impl PickScreen {
+    /// For `at`; the row the focus opens on, what the slot holds.
+    pub(crate) fn open_on(&mut self, at: (usize, usize), pages: &Pages) -> PickRow {
+        *self = Self { at, picked: false };
+        self.current(pages).unwrap_or(PickRow::Pick(None))
+    }
+    /// The page and the slot it is for.
+    pub(crate) fn at(&self) -> (usize, usize) {
+        self.at
+    }
+    /// A pick changed the pages since the last call, which the editor's Undo takes back.
+    pub(crate) fn take_picked(&mut self) -> bool {
+        std::mem::take(&mut self.picked)
+    }
+    /// The row of what the slot holds; none for an action this game doesn't know.
+    fn current(&self, pages: &Pages) -> Option<PickRow> {
+        match pages.page(self.at.0).slot(self.at.1) {
+            Slot::Empty => Some(PickRow::Pick(None)),
+            Slot::Action(action) => Some(PickRow::Pick(Some(*action))),
+            Slot::Missing(_) => None,
+        }
+    }
+}
+
+impl Screen for PickScreen {
+    type Page = ();
+    type Row = PickRow;
+    fn title(&self) -> &'static str {
+        PICK_TITLE
+    }
+    fn stamp(&self, s: &Settings) -> u64 {
+        let (page, slot) = self.at;
+        shell::stamp_of(&(self.at, s.controller.radial.page(page).slot(slot)))
+    }
+    fn sheets(&self, s: &Settings) -> Vec<Sheet<(), PickRow>> {
+        let pages = &s.controller.radial;
+        let (page, slot) = self.at;
+        let direction = lang::get(&format!("horizon.radial.slot.{slot}"));
+        let named = lang::tr(
+            "horizon.radial.pick.slot",
+            &[&direction, &page_label(pages.page(page))],
+        );
+        let current = self.current(pages);
+        let about = lang::get("horizon.radial.pick.about");
+        let mut rows =
+            vec![Row::new(PickRow::Slot, named.clone(), Value::Note).about(about.clone())];
+        for action in std::iter::once(None).chain(RadialAction::ALL.map(Some)) {
+            let id = PickRow::Pick(action);
+            let value = if current == Some(id) {
+                Value::Choice(lang::get("horizon.radial.pick.current"))
+            } else {
+                Value::Press
+            };
+            let name = slot_label(&action.into());
+            rows.push(Row::new(id, name, value).about(about.clone()));
+        }
+        vec![Sheet::new(
+            (),
+            named,
+            about,
+            vec![Group {
+                name: PICK_GROUP,
+                rows,
+            }],
+        )]
+    }
+    fn press(&mut self, s: &mut Settings, row: PickRow, _back: bool) -> Vec<Output> {
+        let PickRow::Pick(action) = row else {
+            return Vec::new();
+        };
+        let (page, slot) = self.at;
+        s.controller.radial.set_slot(page, slot, action.into());
+        self.picked = true;
+        vec![Output::Event(Event::Changed), Output::Done]
+    }
+}
+
+/// The name field and its buttons, centred in the screen but under the title, one row apart.
+const NAME_W: f32 = 200.0;
+const NAME_BLOCK_H: f32 = 100.0;
+const NAME_TOP_MIN: f32 = 30.0;
+const NAME_STEP: f32 = 25.0;
+
+/// What a press on the name's page did.
+#[derive(Clone, Copy, Debug, PartialEq, Eq)]
+pub(crate) enum Named {
+    Nothing,
+    /// Done: the page takes the name.
+    Done,
+    /// Cancel, keeping the old name.
+    Back,
+}
+
+/// A page's name being typed.
+pub(crate) struct NameEntry {
+    page: usize,
+    field: ui::EditBox,
+}
+
+impl NameEntry {
+    fn new(page: usize, name: &str) -> Self {
+        let mut field = ui::EditBox::new(0.0, 0.0, NAME_W, BUTTON_H);
+        field.max_length = radial::NAME_MAX;
+        field.set_value(name);
+        field.focused = true;
+        Self { page, field }
+    }
+
+    /// Done and Cancel, under the field.
+    fn buttons(w: f32, h: f32) -> [([f32; 4], Named); 2] {
+        let (x, top) = ((w / 2.0).floor() - NAME_W / 2.0, name_top(h));
+        let at = |row: f32| [x, top + row * NAME_STEP, NAME_W, BUTTON_H];
+        [(at(1.0), Named::Done), (at(2.0), Named::Back)]
+    }
+
+    pub(crate) fn draw(
+        &mut self,
+        batch: &mut HudBatch,
+        atlas: &HudAtlas,
+        cursor: (f32, f32),
+        in_world: bool,
+    ) {
+        let (w, h) = (batch.width.ceil(), batch.height.ceil());
+        ui::menu_background(batch, atlas, 0.0, 0.0, w, h, in_world);
+        let title = Text::literal(lang::get("horizon.radial.name_title"));
+        style::title(batch, atlas, &title);
+        let field = &mut self.field;
+        let (x, top) = ((w / 2.0).floor() - NAME_W / 2.0, name_top(h));
+        (field.x, field.y, field.width, field.height) = (x, top, NAME_W, BUTTON_H);
+        field.draw(batch, atlas, None);
+        for ([x, y, bw, bh], named) in Self::buttons(w, h) {
+            let (label, action) = match named {
+                Named::Done => ("gui.done", crate::widgets::Action::Done),
+                _ => ("gui.cancel", crate::widgets::Action::Cancel),
+            };
+            let hover = ui::hovered(cursor, x, y, bw, bh);
+            let text = Text::literal(lang::get(label));
+            ui::action_button(batch, atlas, action, x, y, bw, bh, &text, true, hover);
+        }
+    }
+
+    /// A press at `(x, y)` on a screen `w` x `h`.
+    pub(crate) fn click(
+        &mut self,
+        atlas: &HudAtlas,
+        (x, y): (f32, f32),
+        (w, h): (f32, f32),
+    ) -> Named {
+        let hit = Self::buttons(w, h)
+            .into_iter()
+            .find(|([bx, by, bw, bh], _)| ui::hovered((x, y), *bx, *by, *bw, *bh));
+        if let Some((_, named)) = hit {
+            return named;
+        }
+        let field = &mut self.field;
+        field.focused = ui::hovered((x, y), field.x, field.y, field.width, field.height);
+        if field.focused {
+            field.click(atlas, x, false, false);
+        }
+        Named::Nothing
+    }
+
+    /// The name field takes the keys.
+    pub(crate) fn typing(&self) -> bool {
+        self.field.focused
+    }
+
+    pub(crate) fn type_text(&mut self, text: &str) {
+        if self.field.focused {
+            self.field.insert_text(text);
+        }
+    }
+
+    /// A key: Enter is Done, Escape is Cancel, the rest the field's.
+    pub(crate) fn key(&mut self, key: winit::keyboard::KeyCode, text: Option<&str>) -> Named {
+        use winit::keyboard::KeyCode as K;
+        match key {
+            K::Escape => return Named::Back,
+            K::Enter | K::NumpadEnter => return Named::Done,
+            _ if self.field.focused => {
+                if !self.field.key(key, false, false)
+                    && let Some(t) = text
+                {
+                    let typed: String = t.chars().filter(|c| !c.is_control()).collect();
+                    self.field.insert_text(&typed);
+                }
+            }
+            _ => {}
+        }
+        Named::Nothing
+    }
+
+    /// Ctrl+A/C/V/X in the name field; false when it hasn't the focus.
+    pub(crate) fn shortcut(
+        &mut self,
+        shortcut: crate::clipboard::EditShortcut,
+        clipboard: &mut dyn crate::clipboard::Clipboard,
+    ) -> bool {
+        if self.field.focused {
+            self.field.shortcut(shortcut, clipboard);
+        }
+        self.field.focused
+    }
+
+    /// The name into the pages. Left as it was, a default page keeps following the language.
+    pub(crate) fn apply(&self, pages: &mut Pages) -> bool {
+        let changed = self.field.value != page_label(pages.page(self.page));
+        if changed {
+            pages.rename(self.page, &self.field.value);
+        }
+        changed
+    }
+}
+
+/// The name field's top.
+fn name_top(h: f32) -> f32 {
+    ((h - NAME_BLOCK_H) / 2.0).floor().max(NAME_TOP_MIN)
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+    use crate::gamepad::Button as PadButton;
+    use crate::radial::PageName;
+    use crate::settings_shell::{Hosted, Shell};
+    use winit::keyboard::KeyCode as K;
+
+    const SIZE: (f32, f32) = (854.0, 480.0);
+
+    fn rows_of(s: &Settings, page: usize) -> Vec<Row<RadialRow>> {
+        let sheets = RadialScreen::default().sheets(s);
+        let groups = sheets.into_iter().nth(page).unwrap().groups;
+        groups.into_iter().flat_map(|group| group.rows).collect()
+    }
+    fn row(s: &Settings, id: RadialRow) -> Row<RadialRow> {
+        let page = match id {
+            RadialRow::Slot(page, _) | RadialRow::Rename(page) | RadialRow::Delete(page) => page,
+            _ => 0,
+        };
+        rows_of(s, page).into_iter().find(|r| r.id == id).unwrap()
+    }
+    /// A click on `id` through the shell, as the mouse or a controller's A gives it.
+    fn click(shell: &mut Shell<RadialScreen>, s: &mut Settings, id: RadialRow) -> Vec<Output> {
+        let at = shell.point_at(s, SIZE, id);
+        shell.click(s, at, SIZE, false, false, false)
+    }
+
+    /// Undo, at the foot over Done.
+    fn undo(shell: &mut Shell<RadialScreen>, s: &mut Settings) {
+        let [x, y, ..] = shell::Columns::of(SIZE.0, SIZE.1).button(1);
+        shell.click(s, (x + 2.0, y + 2.0), SIZE, false, false, false);
+    }
+
+    #[test]
+    fn a_slot_steps_through_empty_and_every_action_both_ways() {
+        let mut seen = vec![Slot::Empty];
+        let mut slot = Slot::Empty;
+        for _ in RadialAction::ALL {
+            slot = step(&slot, false);
+            seen.push(slot.clone());
+        }
+        assert_eq!(step(&slot, false), Slot::Empty, "the last wraps to Empty");
+        let actions: Vec<_> = seen.iter().filter_map(Slot::action).collect();
+        assert_eq!(actions, RadialAction::ALL.to_vec());
+        assert_eq!(
+            step(&Slot::Empty, true).action(),
+            RadialAction::ALL.last().copied()
+        );
+        let chat = Slot::Action(RadialAction::Chat);
+        assert_eq!(step(&step(&chat, true), false), chat);
+        // A missing action steps on as Empty would.
+        let missing = Slot::Missing("mymod:dash".to_owned());
+        assert_eq!(step(&missing, false), step(&Slot::Empty, false));
+    }
+
+    #[test]
+    fn a_press_on_a_slot_opens_its_list_and_left_and_right_still_step_it() {
+        let mut s = Settings::default();
+        let mut shell = Shell::<RadialScreen>::default();
+        let before = s.controller.radial.clone();
+        let outputs = click(&mut shell, &mut s, RadialRow::Slot(0, 2));
+        assert!(outputs.contains(&Output::Push(Page::ControllerRadialPick)));
+        assert_eq!(shell.screen.picking, Some((0, 2)));
+        assert_eq!(
+            s.controller.radial, before,
+            "the press itself changes nothing"
+        );
+        // Right on the focused row steps it.
+        shell.set_focus(Some(shell::Target::Row(RadialRow::Slot(0, 2))));
+        shell.key(&mut s, K::ArrowRight, None, false, SIZE);
+        let stepped = step(before.page(0).slot(2), false);
+        assert_eq!(*s.controller.radial.page(0).slot(2), stepped);
+    }
+
+    #[test]
+    fn the_list_names_the_slot_marks_its_action_and_a_pick_fills_it() {
+        let mut s = Settings::default();
+        let mut picker = PickScreen::default();
+        // General's right slot holds Commands.
+        let opens_on = picker.open_on((0, 2), &s.controller.radial);
+        assert_eq!(opens_on, PickRow::Pick(Some(RadialAction::Command)));
+        let rows: Vec<_> = picker
+            .sheets(&s)
+            .into_iter()
+            .flat_map(|sheet| sheet.groups)
+            .flat_map(|group| group.rows)
+            .collect();
+        assert_eq!(rows[0].id, PickRow::Slot);
+        assert_eq!(rows[0].value, Value::Note);
+        // Empty, then every action, each once; only the slot's own marked.
+        let picks: Vec<_> = rows[1..].iter().map(|row| row.id).collect();
+        let every: Vec<_> = std::iter::once(None)
+            .chain(RadialAction::ALL.map(Some))
+            .map(PickRow::Pick)
+            .collect();
+        assert_eq!(picks, every);
+        let marked: Vec<_> = rows
+            .iter()
+            .filter(|row| matches!(row.value, Value::Choice(_)))
+            .map(|row| row.id)
+            .collect();
+        assert_eq!(marked, [opens_on]);
+        let outputs = picker.press(&mut s, PickRow::Pick(Some(RadialAction::Chat)), false);
+        assert_eq!(outputs, [Output::Event(Event::Changed), Output::Done]);
+        assert_eq!(
+            *s.controller.radial.page(0).slot(2),
+            Slot::Action(RadialAction::Chat)
+        );
+        assert!(picker.take_picked() && !picker.take_picked());
+        // Empty empties it.
+        picker.press(&mut s, PickRow::Pick(None), false);
+        assert!(s.controller.radial.page(0).slot(2).is_empty());
+    }
+
+    #[test]
+    fn a_missing_action_says_which_it_is() {
+        let mut s = Settings::default();
+        s.controller
+            .radial
+            .set_slot(0, 1, Slot::Missing("mymod:dash".to_owned()));
+        let english = lang::Language::load(&[], "en_us");
+        let (chosen, _) = lang::scoped(english, || row(&s, RadialRow::Slot(0, 1)).chosen);
+        assert!(chosen.is_some_and(|text| text.contains("mymod:dash")));
+    }
+
+    #[test]
+    fn a_slot_changes_alone_and_undo_puts_back_what_the_screen_found() {
+        let mut s = Settings::default();
+        let mut shell = Shell::<RadialScreen>::default();
+        let before = s.controller.radial.page(0).clone();
+        shell.set_focus(Some(shell::Target::Row(RadialRow::Slot(0, 0))));
+        let outputs = shell.key(&mut s, K::ArrowRight, None, false, SIZE);
+        assert!(outputs.contains(&Output::Event(Event::Changed)));
+        let after = s.controller.radial.page(0);
+        assert_eq!(*after.slot(0), step(before.slot(0), false));
+        assert_eq!(after.slots()[1..], before.slots()[1..]);
+        assert!(shell.changed());
+        undo(&mut shell, &mut s);
+        assert_eq!(s.controller.radial, Pages::default());
+        assert!(!shell.changed());
+    }
+
+    #[test]
+    fn delete_and_reset_act_at_once_and_undo_takes_them_back() {
+        let mut s = Settings::default();
+        s.controller.radial.rename(1, "Mine");
+        let found = s.controller.radial.clone();
+        let mut shell = Shell::<RadialScreen>::default();
+        click(&mut shell, &mut s, RadialRow::Delete(0));
+        assert_eq!(s.controller.radial.len(), 1);
+        assert_eq!(page_label(s.controller.radial.page(0)), "Mine");
+        // One page left: it can't go, and the strip says why.
+        let delete = row(&s, RadialRow::Delete(0));
+        assert!(!delete.live && delete.why.is_some());
+        let reset = row(&s, RadialRow::Reset);
+        assert!(reset.live);
+        shell.screen.take_shown();
+        click(&mut shell, &mut s, RadialRow::Reset);
+        assert_eq!(s.controller.radial, Pages::default());
+        assert!(!row(&s, RadialRow::Reset).live, "already the defaults");
+        assert_eq!(shell.screen.take_shown(), Some(0));
+        undo(&mut shell, &mut s);
+        assert_eq!(s.controller.radial, found);
+    }
+
+    #[test]
+    fn new_pages_stop_at_the_most_and_the_new_one_shows() {
+        let mut s = Settings::default();
+        let mut screen = RadialScreen::default();
+        while row(&s, RadialRow::NewPage).live {
+            screen.press(&mut s, RadialRow::NewPage, false);
+            assert_eq!(screen.take_shown(), Some(s.controller.radial.len() - 1));
+        }
+        assert_eq!(s.controller.radial.len(), radial::MAX_PAGES);
+        assert!(row(&s, RadialRow::NewPage).why.is_some());
+        // Every page is a sheet, named as the overlay names it.
+        let sheets = screen.sheets(&s);
+        assert_eq!(sheets.len(), radial::MAX_PAGES);
+        assert_eq!(sheets[0].name, page_label(s.controller.radial.page(0)));
+    }
+
+    #[test]
+    fn a_deleted_last_page_leaves_the_one_before_it_showing() {
+        let mut s = Settings::default();
+        let mut screen = RadialScreen::default();
+        screen.press(&mut s, RadialRow::Delete(1), false);
+        assert_eq!(screen.take_shown(), Some(0));
+    }
+
+    #[test]
+    fn rename_opens_the_name_page_and_only_done_with_a_new_name_renames() {
+        let general = Pages::default().page(0).name.clone();
+        let mut s = Settings::default();
+        let mut screen = RadialScreen::default();
+        let outputs = screen.press(&mut s, RadialRow::Rename(0), false);
+        assert_eq!(outputs, vec![Output::Push(Page::ControllerRadialName)]);
+        let entry = screen.naming.as_mut().unwrap();
+        // Done with the name as it was: a default page keeps following the language.
+        assert_eq!(entry.key(K::Enter, None), Named::Done);
+        assert!(!entry.apply(&mut s.controller.radial));
+        assert_eq!(s.controller.radial.page(0).name, general);
+        entry.type_text("!");
+        assert_eq!(entry.key(K::Escape, None), Named::Back);
+        entry.field.set_value("Mine");
+        entry.type_text("!");
+        assert!(entry.apply(&mut s.controller.radial));
+        assert_eq!(
+            s.controller.radial.page(0).name,
+            PageName::Custom("Mine!".to_owned())
+        );
+    }
+
+    #[test]
+    fn undo_puts_back_a_name_given_on_the_name_page() {
+        let mut s = Settings::default();
+        s.controller.radial.rename(1, "Mine");
+        let mut shell = Shell::<RadialScreen>::default();
+        shell.show(1);
+        click(&mut shell, &mut s, RadialRow::Rename(1));
+        let entry = shell.screen.naming.as_mut().unwrap();
+        entry.field.set_value("Building");
+        // As the options screen does on Done: the name page changed what Undo puts back.
+        let entry = shell.screen.naming.take().unwrap();
+        assert!(entry.apply(&mut s.controller.radial));
+        shell.changed_elsewhere();
+        assert_eq!(page_label(s.controller.radial.page(1)), "Building");
+        assert!(shell.changed());
+        undo(&mut shell, &mut s);
+        assert_eq!(page_label(s.controller.radial.page(1)), "Mine");
+        assert!(!shell.changed());
+    }
+
+    #[test]
+    fn a_nintendo_pad_going_by_its_letters_names_its_own_opener() {
+        let mut s = Settings::default();
+        // Selecting with the left stick, the top face button (North) can open it.
+        s.controller.radial_stick = gamepad::RadialStick::Left;
+        s.controller.bind(OPENER, Some(gamepad::Button::North));
+        s.controller.glyphs = gamepad::GlyphStyle::Nintendo;
+        let label = |s: &Settings| {
+            let glyphs = Glyphs::of(&s.controller, gamepad::GlyphStyle::Nintendo);
+            match opener_row(s, glyphs).value {
+                Value::Binding(Binding {
+                    shown: Shown::Pad { glyph, .. },
+                    ..
+                }) => glyph.expect("bound").label().to_owned(),
+                other => panic!("{other:?}"),
+            }
+        };
+        // By places, the top button: printed X on a Nintendo pad.
+        s.controller.nintendo_letters = false;
+        assert_eq!(label(&s), "X");
+        // By letters, the part is played by the button printed Y (on the left).
+        s.controller.nintendo_letters = true;
+        assert_eq!(label(&s), "Y");
+    }
+
+    #[test]
+    fn the_opener_row_names_its_button_and_says_what_gets_in_the_way() {
+        let mut s = Settings::default();
+        let glyphs = Glyphs::of(&s.controller, gamepad::GlyphStyle::Xbox);
+        let shown = |s: &Settings| match opener_row(s, glyphs).value {
+            Value::Binding(Binding {
+                capture,
+                shown: Shown::Pad { glyph, .. },
+                ..
+            }) => {
+                assert_eq!(capture, Capture::Pad(OPENER));
+                glyph
+            }
+            other => panic!("{other:?}"),
+        };
+        let bound = s.controller.binding(OPENER).unwrap();
+        // The button on its glyph.
+        let glyph = shown(&s).expect("the opener's glyph");
+        assert_eq!(glyph.part(), bound);
+        assert_eq!(glyph.label(), "→");
+        assert_eq!(opener_row(&s, glyphs).chosen, None);
+        s.controller.bind("key.chat", Some(bound));
+        let shared = opener_row(&s, glyphs).chosen;
+        assert!(shared.is_some(), "a shared button");
+        s.controller.bind(OPENER, None);
+        let unbound = opener_row(&s, glyphs).chosen;
+        assert!(unbound.is_some() && unbound != shared && shown(&s).is_none());
+        // A press waits for a button on the row, and Undo takes a new one back.
+        let mut shell = Shell::<RadialScreen>::default();
+        s.controller.bind(OPENER, Some(bound));
+        let outputs = click(&mut shell, &mut s, RadialRow::Opener);
+        assert!(outputs.contains(&Output::Bind(Capture::Pad(OPENER))));
+        assert!(shell.changed());
+        s.controller.bind(OPENER, Some(PadButton::North));
+        undo(&mut shell, &mut s);
+        assert_eq!(s.controller.binding(OPENER), Some(bound));
+    }
+
+    #[test]
+    fn every_string_has_a_horizon_key() {
+        let atlas =
+            HudAtlas::build(std::path::Path::new("/nonexistent/horizon-test-assets")).unwrap();
+        let english = lang::Language::load(&[], "en_us");
+        let ((), missed) = lang::scoped(english, || {
+            let mut s = Settings::default();
+            s.controller.bind("key.chat", Some(PadButton::DPadRight));
+            let mut shell = Shell::<RadialScreen>::default();
+            let draw = |shell: &mut Shell<RadialScreen>, s: &Settings| {
+                let mut batch = HudBatch::new([854, 480]);
+                shell.draw(s, &mut batch, &atlas, (0.0, 0.0), false, None);
+            };
+            // Every page's rows are built, with what the strip says of each.
+            draw(&mut shell, &s);
+            s.controller.bind(OPENER, None);
+            s.controller.radial.remove(1);
+            while s.controller.radial.add().is_some() {}
+            draw(&mut shell, &s);
+            s.controller.radial = Pages::default();
+            s.controller.radial.remove(1);
+            draw(&mut shell, &s);
+            let mut batch = HudBatch::new([854, 480]);
+            let waiting = Some(Capture::Pad(OPENER));
+            shell.draw(&s, &mut batch, &atlas, (0.0, 0.0), false, waiting);
+            let mut entry = NameEntry::new(0, "Mine");
+            let mut batch = HudBatch::new([854, 480]);
+            entry.draw(&mut batch, &atlas, (0.0, 0.0), false);
+            let mut picker = Shell::<PickScreen>::default();
+            picker.screen.open_on((0, 1), &s.controller.radial);
+            let mut batch = HudBatch::new([854, 480]);
+            picker.draw(&s, &mut batch, &atlas, (0.0, 0.0), false, None);
+        });
+        // Vanilla's own (gui.done...) come from the game's resources, not bundled ones.
+        let missed: Vec<_> = missed
+            .iter()
+            .filter(|key| key.starts_with("horizon.") || !key.contains('.'))
+            .collect();
+        assert!(missed.is_empty(), "no text for {missed:?}");
+    }
+}
@@ -869,8 +869,14 @@ pub enum Opt {
    PadNintendoButtons,
    PadKeyboard,
    PadGameplayGuide,
+    /// The radial menu's opener held or pressed once (`PadSettings::radial_mode`).
+    PadRadialMode,
+    /// The stick the radial menu selects with (`PadSettings::radial_stick`).
+    PadRadialStick,
    /// `options.modelPart.*`: one skin layer (index into `options_file::MODEL_PARTS`).
    ModelPart(usize),
+    /// A slider of a page a crate registered (`horizon_hooks::pages`): (page, row).
+    Page(usize, usize),
    /// 3D skin layers: the player's outer layer as extruded slabs.
    SkinLayers3d,
    MainHand,
@@ -0,0 +1,815 @@
+use super::*;
+use crate::options_ui::Event;
+use winit::keyboard::KeyCode as K;
+
+const SIZE: (f32, f32) = (854.0, 480.0);
+const SHORT: (f32, f32) = (480.0, 240.0);
+const CHANGED: Output = Output::Event(Event::Changed);
+
+/// A screen with what Extras doesn't have: two pages, a slider, a value with descriptions of
+/// its own, and a row a wheel steps.
+#[derive(Default)]
+struct Probe {
+    slider: f32,
+    choice: usize,
+    pressed: Vec<(u32, bool)>,
+    /// How many times its rows were built.
+    built: std::cell::Cell<usize>,
+}
+const CHOICES: [(&str, &str); 2] = [("Red", "Paints it red."), ("Blue", "Paints it blue.")];
+const SLIDER: u32 = 0;
+const CHOICE: u32 = 1;
+const FIRST_FILLER: u32 = 10;
+const FILLERS: u32 = 40;
+const GREY: u32 = 100;
+const WHY: &str = "Not here.";
+impl Screen for Probe {
+    type Page = u8;
+    type Row = u32;
+    fn title(&self) -> &'static str {
+        "Probe"
+    }
+    /// Its rows read the field of view, besides its own state.
+    fn stamp(&self, s: &Settings) -> u64 {
+        stamp_of(&s.fov)
+    }
+    fn sheets(&self, s: &Settings) -> Vec<Sheet<u8, u32>> {
+        self.built.set(self.built.get() + 1);
+        let (value, chosen) = CHOICES[self.choice];
+        let mut rows = vec![
+            Row::new(
+                SLIDER,
+                "Level".to_owned(),
+                Value::Slider {
+                    position: self.slider,
+                    steps: Some(10),
+                    text: s.fov.to_string(),
+                },
+            ),
+            Row {
+                chosen: Some(chosen.to_owned()),
+                ..Row::new(CHOICE, "Paint".to_owned(), Value::Choice(value.to_owned()))
+                    .about("Picks a colour.".to_owned())
+            },
+            Row::new(GREY, "Greyed".to_owned(), Value::Press)
+                .about("Does a thing.".to_owned())
+                .blocked(Some(WHY.to_owned())),
+        ];
+        rows.extend((0..FILLERS).map(|i| {
+            Row::new(FIRST_FILLER + i, format!("Filler {i}"), Value::Press)
+                .about("Does nothing.".to_owned())
+        }));
+        let elsewhere = vec![Row::new(99, "Elsewhere".to_owned(), Value::Press)];
+        vec![
+            Sheet::new(
+                0,
+                "One".to_owned(),
+                "The first.".to_owned(),
+                vec![Group { name: "G", rows }],
+            ),
+            Sheet::new(
+                1,
+                "Two".to_owned(),
+                "The second.".to_owned(),
+                vec![Group {
+                    name: "H",
+                    rows: elsewhere,
+                }],
+            ),
+        ]
+    }
+    fn press(&mut self, s: &mut Settings, row: u32, back: bool) -> Vec<Output> {
+        self.pressed.push((row, back));
+        match row {
+            CHOICE => self.choice = (self.choice + 1) % CHOICES.len(),
+            FIRST_FILLER => s.fov += 1.0,
+            _ => {}
+        }
+        vec![CHANGED]
+    }
+    fn undoes(&self) -> bool {
+        true
+    }
+    fn undo(&mut self, s: &mut Settings, before: &Settings) -> Vec<Output> {
+        s.fov = before.fov;
+        Vec::new()
+    }
+    fn slide(&mut self, _: &mut Settings, _: u32, position: f32) {
+        self.slider = position;
+    }
+    fn wheel_step(&mut self, _: &mut Settings, row: u32, _: bool) -> Option<Vec<Output>> {
+        (row == CHOICE).then(|| {
+            self.choice = (self.choice + 1) % CHOICES.len();
+            vec![CHANGED]
+        })
+    }
+}
+
+fn middle_of(shell: &mut Shell<Probe>, row: u32, size: (f32, f32)) -> (f32, f32) {
+    shell.point_at(&Settings::default(), size, row)
+}
+
+fn atlas() -> HudAtlas {
+    HudAtlas::build(std::path::Path::new("/nonexistent/horizon-test-assets")).unwrap()
+}
+
+/// What one frame asks of a screen: a draw, then the stick's scroll, an arrow key and the wheel
+/// away from any row, at the size it was drawn at.
+fn frame(shell: &mut Shell<Probe>, s: &mut Settings, atlas: &HudAtlas) -> (f32, f32) {
+    let mut batch = HudBatch::new([1708, 960]);
+    shell.draw(s, &mut batch, atlas, (0.0, 0.0), false, None);
+    let size = (batch.width, batch.height);
+    shell.scroll(s, size, -1.0);
+    shell.key(s, K::ArrowDown, None, false, size);
+    shell.wheel(s, size, (0.0, 0.0), 1.0);
+    size
+}
+
+#[test]
+fn rows_are_built_once_and_again_only_when_what_they_read_changes() {
+    let atlas = atlas();
+    let mut s = Settings::default();
+    let mut shell = Shell::<Probe>::default();
+    let built = |shell: &Shell<Probe>| shell.screen.built.get();
+    let reads = |shell: &mut Shell<Probe>, s: &Settings, size, end: &str| {
+        let view = shell.view(s, size);
+        let mut labels = view.rows.iter().map(|r| r.label(r.value_text().as_deref()));
+        labels.any(|label| label.ends_with(end))
+    };
+    // Each of the four built them before: now the first frame builds them once, the next none.
+    let size = frame(&mut shell, &mut s, &atlas);
+    assert_eq!(built(&shell), 1);
+    frame(&mut shell, &mut s, &atlas);
+    assert_eq!(built(&shell), 1);
+    // A press changes the screen's own state: its row reads the new value.
+    let at = middle_of(&mut shell, CHOICE, size);
+    shell.click(&mut s, at, size, false, false, false);
+    assert!(reads(&mut shell, &s, size, "Blue"));
+    // A setting changed elsewhere (a key bound, a command) shows on the next frame.
+    s.fov = 90.0;
+    frame(&mut shell, &mut s, &atlas);
+    assert!(reads(&mut shell, &s, size, "90"));
+    let before = built(&shell);
+    frame(&mut shell, &mut s, &atlas);
+    assert_eq!(built(&shell), before);
+    // Searching, and another size, build them again.
+    shell.type_text("filler");
+    shell.view(&s, size);
+    assert_eq!(built(&shell), before + 1);
+    shell.view(&s, SHORT);
+    assert_eq!(built(&shell), before + 2);
+    // So does another language, and coming back from it.
+    lang::scoped(lang::Language::load(&[], "de_de"), || shell.view(&s, SHORT));
+    assert_eq!(built(&shell), before + 3);
+    shell.view(&s, SHORT);
+    assert_eq!(built(&shell), before + 4);
+}
+
+#[test]
+fn a_row_the_list_hides_part_of_scrolls_into_view_when_focused_and_then_takes_a_press() {
+    let mut s = Settings::default();
+    let mut shell = Shell::<Probe>::default();
+    let cols = Columns::of(SHORT.0, SHORT.1);
+    // A filler far down, scrolled to just over the bottom: its middle is under the list's edge.
+    let cut = FIRST_FILLER + 20;
+    let view = shell.view(&s, SHORT);
+    let (_, y) = shell.placed(&view).find(|(r, _)| r.id == cut).unwrap();
+    shell.scroll.amount = y - cols.bottom + style::ROW / 2.0 - 1.0;
+    let rect = cols.row(y - shell.scroll.amount);
+    assert!(
+        rect[1] + rect[3] / 2.0 >= cols.bottom,
+        "the row's middle is hidden"
+    );
+    let moved = Hosted::reveal(&mut shell, &s, SHORT, rect).unwrap();
+    let shown = [rect[0], rect[1] + moved, rect[2], rect[3]];
+    assert!(moved < 0.0 && shown[1] + shown[3] <= cols.bottom);
+    // All in view, it stays put.
+    assert_eq!(Hosted::reveal(&mut shell, &s, SHORT, shown), None);
+    let middle = (shown[0] + 4.0, shown[1] + shown[3] / 2.0);
+    assert_eq!(
+        shell.click(&mut s, middle, SHORT, false, false, false),
+        vec![CLICK, CHANGED]
+    );
+    assert_eq!(shell.screen.pressed, [(cut, false)]);
+}
+
+#[test]
+fn undo_appears_after_a_change_and_puts_back_what_the_screen_opened_with() {
+    let mut s = Settings::default();
+    let mut shell = Shell::<Probe>::default();
+    let undo = Columns::of(SIZE.0, SIZE.1).button(1);
+    let on_undo = (undo[0] + 2.0, undo[1] + 2.0);
+    // Nothing changed: there is no Undo to press.
+    assert!(
+        shell
+            .click(&mut s, on_undo, SIZE, false, false, false)
+            .is_empty()
+    );
+    let at = middle_of(&mut shell, FIRST_FILLER, SIZE);
+    shell.click(&mut s, at, SIZE, false, false, false);
+    assert_eq!(s.fov, 71.0);
+    // Another option changed meanwhile isn't the screen's to put back.
+    s.chat_opacity = 0.25;
+    assert_eq!(
+        shell.click(&mut s, on_undo, SIZE, false, false, false),
+        vec![CLICK, CHANGED]
+    );
+    assert_eq!((s.fov, s.chat_opacity), (70.0, 0.25));
+    assert!(
+        shell
+            .click(&mut s, on_undo, SIZE, false, false, false)
+            .is_empty()
+    );
+    // From the keyboard: Tab reaches it, Enter undoes and leaves the focus on Done.
+    shell.click(&mut s, at, SIZE, false, false, false);
+    let reached = (0..100).any(|_| {
+        shell.key(&mut s, K::Tab, None, false, SIZE);
+        shell.focus == Some(Target::Undo)
+    });
+    assert!(reached);
+    assert_eq!(
+        shell.key(&mut s, K::Enter, None, false, SIZE),
+        vec![CLICK, CHANGED]
+    );
+    assert_eq!(s.fov, 70.0);
+    assert_eq!(shell.focus, Some(Target::Done));
+}
+
+#[test]
+fn the_strip_says_why_a_greyed_row_cant_be_used() {
+    let atlas = atlas();
+    let s = Settings::default();
+    let mut shell = Shell::<Probe>::default();
+    let mut batch = HudBatch::new([1708, 960]);
+    let size = (batch.width, batch.height);
+    let strip = |batch: &mut HudBatch, shell: &mut Shell<Probe>, at| {
+        shell.draw(&s, batch, &atlas, at, false, None);
+        crate::widgets::end_frame(crate::widgets::generation() + 1);
+        let dock = Columns::of(size.0, size.1).dock;
+        let labelled = crate::widgets::last_labelled();
+        let found = labelled.iter().find(|w| [w.x, w.y, w.w, w.h] == dock);
+        found.map(|w| w.label.clone())
+    };
+    let grey = middle_of(&mut shell, GREY, size);
+    assert_eq!(strip(&mut batch, &mut shell, grey).as_deref(), Some(WHY));
+    let choice = middle_of(&mut shell, CHOICE, size);
+    assert_eq!(
+        strip(&mut batch, &mut shell, choice).as_deref(),
+        Some(CHOICES[0].1)
+    );
+}
+
+#[test]
+fn growing_the_window_keeps_the_scroll_within_the_list() {
+    let s = Settings::default();
+    let mut shell = Shell::<Probe>::default();
+    shell.scroll(&s, SIZE, -1000.0);
+    assert!(shell.scroll.amount > 0.0);
+    let tall = (SIZE.0, 4000.0);
+    let view = shell.view(&s, tall);
+    assert_eq!(shell.scroll.amount, 0.0);
+    let first = shell.placed(&view).next().map(|(_, y)| y).unwrap();
+    assert!(first >= view.cols.top);
+}
+
+#[test]
+fn one_scroll_path_moves_the_list_for_wheel_and_stick_alike() {
+    let mut s = Settings::default();
+    let mut shell = Shell::<Probe>::default();
+    let rate = SCROLL_RATE;
+    // The wheel away from any row, and `scroll`, which a stick and a D-pad use.
+    shell.wheel(&mut s, SIZE, (0.0, 0.0), -1.0);
+    assert_eq!(shell.scroll.amount, rate);
+    shell.scroll(&s, SIZE, -2.0);
+    assert_eq!(shell.scroll.amount, 3.0 * rate);
+    shell.scroll(&s, SIZE, 100.0);
+    assert_eq!(shell.scroll.amount, 0.0);
+}
+
+#[test]
+fn the_wheel_steps_a_row_only_with_the_extra_on_and_only_where_the_screen_says() {
+    let mut s = Settings::default();
+    let mut shell = Shell::<Probe>::default();
+    let over_choice = middle_of(&mut shell, CHOICE, SIZE);
+    shell.wheel(&mut s, SIZE, over_choice, -1.0);
+    assert_eq!(shell.screen.choice, 0);
+    assert_eq!(shell.scroll.amount, SCROLL_RATE);
+    s.extras.wheel_cycles_settings = true;
+    shell.scroll.amount = 0.0;
+    let outputs = shell.wheel(&mut s, SIZE, over_choice, -1.0);
+    assert_eq!(outputs, vec![CHANGED]);
+    assert_eq!(shell.screen.choice, 1);
+    assert_eq!(shell.scroll.amount, 0.0);
+    // A row the screen doesn't step scrolls, the greyed one too.
+    let over_grey = middle_of(&mut shell, GREY, SIZE);
+    assert!(shell.wheel(&mut s, SIZE, over_grey, -1.0).is_empty());
+    assert_eq!(shell.scroll.amount, SCROLL_RATE);
+}
+
+#[test]
+fn a_row_says_what_its_chosen_value_does_and_is_found_by_what_it_does() {
+    let mut s = Settings::default();
+    let mut shell = Shell::<Probe>::default();
+    let about = |shell: &mut Shell<Probe>, s: &Settings| {
+        let view = shell.view(s, SIZE);
+        let row = view.rows.iter().find(|r| r.id == CHOICE).unwrap();
+        row.described().to_owned()
+    };
+    assert_eq!(about(&mut shell, &s), "Paints it red.");
+    let at = middle_of(&mut shell, CHOICE, SIZE);
+    shell.click(&mut s, at, SIZE, false, false, false);
+    assert_eq!(about(&mut shell, &s), "Paints it blue.");
+    // The search reads the row's own description, on every page.
+    shell.type_text("colour");
+    let view = shell.view(&s, SIZE);
+    let found: Vec<u32> = view.rows.iter().map(|r| r.id).collect();
+    assert!(found.contains(&CHOICE) && !found.contains(&99));
+    shell.search.set_value("elsewhere");
+    shell.focus = None;
+    let view = shell.view(&s, SIZE);
+    assert_eq!(view.rows.iter().map(|r| r.id).collect::<Vec<_>>(), [99]);
+}
+
+#[test]
+fn a_press_on_the_track_slides_and_on_the_name_only_focuses() {
+    let mut s = Settings::default();
+    let mut shell = Shell::<Probe>::default();
+    let at = middle_of(&mut shell, SLIDER, SIZE);
+    assert!(
+        shell
+            .click(&mut s, at, SIZE, false, false, false)
+            .is_empty()
+    );
+    assert_eq!(shell.screen.slider, 0.0);
+    let (track, width) = Columns::of(SIZE.0, SIZE.1).track();
+    let mid = (track + width / 2.0, at.1);
+    assert_eq!(
+        shell.click(&mut s, mid, SIZE, false, false, false),
+        vec![DRAGGED]
+    );
+    assert_eq!(shell.screen.slider, 0.5);
+    let end = (track + width, at.1);
+    assert_eq!(
+        shell.click(&mut s, end, SIZE, true, false, false),
+        vec![DRAGGED]
+    );
+    assert_eq!(shell.screen.slider, 1.0);
+    assert!(shell.release().is_some());
+    assert!(shell.release().is_none());
+}
+
+#[test]
+fn the_keyboard_walks_the_live_rows_past_the_view_and_presses_them() {
+    let mut s = Settings::default();
+    let mut shell = Shell::<Probe>::default();
+    let mut key = |shell: &mut Shell<Probe>, k| shell.key(&mut s, k, None, false, SHORT);
+    // Tab: the search, the two pages, then the first row.
+    for _ in 0..4 {
+        key(&mut shell, K::Tab);
+    }
+    assert_eq!(shell.focus, Some(Target::Row(SLIDER)));
+    // A slider Tab reaches changes with the arrows, in its steps.
+    key(&mut shell, K::ArrowRight);
+    assert!((shell.screen.slider - 0.1).abs() < f32::EPSILON);
+    // The arrows go on past the greyed row and rows out of view, which scroll in.
+    key(&mut shell, K::ArrowDown);
+    assert_eq!(shell.focus, Some(Target::Row(CHOICE)));
+    key(&mut shell, K::ArrowDown);
+    assert_eq!(shell.focus, Some(Target::Row(FIRST_FILLER)));
+    for _ in 0..30 {
+        key(&mut shell, K::ArrowDown);
+    }
+    assert_eq!(shell.focus, Some(Target::Row(FIRST_FILLER + 30)));
+    assert!(shell.scroll.amount > 0.0);
+    assert_eq!(key(&mut shell, K::Enter), vec![CLICK, CHANGED]);
+    assert_eq!(shell.screen.pressed, [(FIRST_FILLER + 30, false)]);
+    assert_eq!(key(&mut shell, K::Escape), vec![Output::Done]);
+}
+
+#[test]
+fn left_and_right_step_a_focused_choice_and_leave_other_rows() {
+    let mut s = Settings::default();
+    let mut shell = Shell::<Probe>::default();
+    let mut key = |shell: &mut Shell<Probe>, k| shell.key(&mut s, k, None, false, SIZE);
+    shell.set_focus(Some(Target::Row(CHOICE)));
+    // Right is a press, Left a Shift press: the screen's own way back, and the focus stays.
+    assert_eq!(key(&mut shell, K::ArrowRight), vec![CLICK, CHANGED]);
+    assert_eq!(key(&mut shell, K::ArrowLeft), vec![CLICK, CHANGED]);
+    assert_eq!(shell.screen.pressed, [(CHOICE, false), (CHOICE, true)]);
+    assert_eq!(shell.focus, Some(Target::Row(CHOICE)));
+    assert!(shell.changed);
+    // A row that isn't a choice: Left goes to the page list, as before.
+    shell.set_focus(Some(Target::Row(FIRST_FILLER)));
+    assert!(key(&mut shell, K::ArrowLeft).is_empty());
+    assert!(matches!(shell.focus, Some(Target::Page(_))));
+    assert_eq!(shell.screen.pressed.len(), 2);
+}
+
+#[test]
+fn a_drawn_choice_tells_the_pad_its_arrows_step_it() {
+    let atlas = atlas();
+    let s = Settings::default();
+    let mut shell = Shell::<Probe>::default();
+    let mut batch = HudBatch::new([1708, 960]);
+    shell.draw(&s, &mut batch, &atlas, (0.0, 0.0), false, None);
+    crate::widgets::end_frame(u64::MAX);
+    let view = shell.view(&s, (batch.width, batch.height));
+    let rect_of = |id| {
+        let mut placed = shell.placed(&view);
+        view.cols.row(placed.find(|(r, _)| r.id == id).unwrap().1)
+    };
+    assert!(crate::widgets::last_steps_value(rect_of(CHOICE)));
+    assert!(!crate::widgets::last_steps_value(rect_of(SLIDER)));
+    assert!(!crate::widgets::last_steps_value(rect_of(FIRST_FILLER)));
+}
+
+/// A controller presses with a click, then moves its own focus: only keys show this one.
+#[test]
+fn leaving_the_search_field_gives_the_keys_back() {
+    let mut s = Settings::default();
+    let mut shell = Shell::<Probe>::default();
+    let view = shell.view(&s, SIZE);
+    let [x, y, w, h] = view.cols.search();
+    shell.click(
+        &mut s,
+        (x + w / 2.0, y + h / 2.0),
+        SIZE,
+        false,
+        false,
+        false,
+    );
+    assert!(shell.typing());
+    Hosted::blur_search(&mut shell);
+    assert!(!shell.typing());
+    // Another focus isn't dropped.
+    let at = middle_of(&mut shell, FIRST_FILLER, SIZE);
+    shell.click(&mut s, at, SIZE, false, false, false);
+    Hosted::blur_search(&mut shell);
+    shell.key(&mut s, K::ArrowDown, None, false, SIZE);
+    assert!(shell.shows_focus(Target::Row(FIRST_FILLER + 1)));
+}
+
+#[test]
+fn a_key_that_moves_nothing_shows_no_focus() {
+    let mut s = Settings::default();
+    let mut shell = Shell::<Probe>::default();
+    let at = middle_of(&mut shell, FIRST_FILLER, SIZE);
+    shell.click(&mut s, at, SIZE, false, false, false);
+    shell.key(&mut s, K::ShiftLeft, None, false, SIZE);
+    assert!(!shell.shows_focus(Target::Row(FIRST_FILLER)));
+}
+
+#[test]
+fn a_cut_description_says_so() {
+    assert_eq!(cut_off("off, it never "), "off, it never…");
+}
+
+#[test]
+fn a_click_leaves_no_focus_showing_until_a_key_moves_it() {
+    let mut s = Settings::default();
+    let mut shell = Shell::<Probe>::default();
+    let at = middle_of(&mut shell, FIRST_FILLER, SIZE);
+    shell.click(&mut s, at, SIZE, false, false, false);
+    assert!(!shell.shows_focus(Target::Row(FIRST_FILLER)));
+    // The next key goes on from the row clicked, and shows where it went.
+    shell.key(&mut s, K::ArrowDown, None, false, SIZE);
+    assert!(shell.shows_focus(Target::Row(FIRST_FILLER + 1)));
+}
+
+#[test]
+fn a_taller_strip_takes_from_the_list_as_far_as_the_list_keeps_its_height() {
+    let (wide, base) = (
+        Columns::of(480.0, 270.0).with_note_lines(4),
+        Columns::of(480.0, 270.0),
+    );
+    assert_eq!(wide.note_lines, 4);
+    assert_eq!(wide.bottom, base.bottom - 2.0 * NOTE_LINE_H);
+    assert_eq!(wide.dock[1] + wide.dock[3], base.dock[1] + base.dock[3]);
+    assert_eq!(wide.button(0), base.button(0));
+    // A 720p window at scale 4 has room for one more line, not two.
+    let short = Columns::of(320.0, 180.0).with_note_lines(4);
+    assert_eq!(short.note_lines, 3);
+    assert!(short.bottom - short.top >= MIN_LIST_H);
+}
+
+#[test]
+fn shift_presses_a_row_backwards() {
+    let mut s = Settings::default();
+    let mut shell = Shell::<Probe>::default();
+    let at = middle_of(&mut shell, FIRST_FILLER, SIZE);
+    shell.click(&mut s, at, SIZE, false, false, true);
+    // The right button is not a press.
+    shell.click(&mut s, at, SIZE, false, true, false);
+    assert_eq!(shell.screen.pressed, [(FIRST_FILLER, true)]);
+}
+
+#[test]
+fn a_click_on_a_greyed_row_does_nothing_and_done_leaves() {
+    let mut s = Settings::default();
+    let mut shell = Shell::<Probe>::default();
+    let at = middle_of(&mut shell, GREY, SIZE);
+    assert!(
+        shell
+            .click(&mut s, at, SIZE, false, false, false)
+            .is_empty()
+    );
+    assert!(shell.screen.pressed.is_empty());
+    let [x, y, w, h] = Columns::of(SIZE.0, SIZE.1).button(0);
+    let at = (x + w / 2.0, y + h / 2.0);
+    assert_eq!(
+        shell.click(&mut s, at, SIZE, false, false, false),
+        vec![CLICK, Output::Done]
+    );
+}
+
+#[test]
+fn a_page_picked_shows_alone() {
+    let mut s = Settings::default();
+    let mut shell = Shell::<Probe>::default();
+    let [x, y, w, h] = Columns::of(SIZE.0, SIZE.1).page(1);
+    let at = (x + w / 2.0, y + h / 2.0);
+    assert_eq!(
+        shell.click(&mut s, at, SIZE, false, false, false),
+        vec![CLICK]
+    );
+    let view = shell.view(&s, SIZE);
+    assert_eq!(view.rows.iter().map(|r| r.id).collect::<Vec<_>>(), [99]);
+}
+
+/// A screen with more pages than a short view's page list has room for: a page of its own,
+/// then a section of `PAGES` under a line, one more page out of the list that the section's
+/// first page links to, and a change that waits for Apply.
+#[derive(Default)]
+struct Pages {
+    pending: bool,
+    applied: usize,
+}
+const PAGES: u8 = 12;
+const HOME: u8 = 0;
+const DEEP: u8 = 100;
+const LINK: u32 = 1000;
+const WAITS: u32 = 1001;
+const SECTION: &str = "Section";
+impl Screen for Pages {
+    type Page = u8;
+    type Row = u32;
+    fn title(&self) -> &'static str {
+        "Pages"
+    }
+    fn stamp(&self, _: &Settings) -> u64 {
+        stamp_of(&self.pending)
+    }
+    fn sheets(&self, _: &Settings) -> Vec<Sheet<u8, u32>> {
+        let page = |id: u8, name: String, rows| {
+            Sheet::new(id, name, String::new(), vec![Group { name: "G", rows }])
+        };
+        let change = Row::new(WAITS, "Change".to_owned(), Value::Press);
+        let mut sheets = vec![page(HOME, "Home".to_owned(), vec![change])];
+        for i in 1..=PAGES {
+            let mut rows = vec![Row::new(u32::from(i), format!("Row {i}"), Value::Press)];
+            if i == 1 {
+                rows.push(Row::new(LINK, "Deeper...".to_owned(), Value::Press));
+            }
+            let mut sheet = page(i, format!("Page {i}"), rows);
+            sheet.heading = (i == 1).then(|| SECTION.to_owned());
+            sheets.push(sheet);
+        }
+        let deep = Row::new(u32::from(DEEP), "Deep".to_owned(), Value::Press);
+        let mut deeper = page(DEEP, "Deeper".to_owned(), vec![deep]);
+        deeper.listed = false;
+        sheets.push(deeper);
+        sheets
+    }
+    fn press(&mut self, _: &mut Settings, row: u32, _: bool) -> Vec<Output> {
+        self.pending |= row == WAITS;
+        vec![CHANGED]
+    }
+    fn link(&self, row: u32) -> Option<u8> {
+        (row == LINK).then_some(DEEP)
+    }
+    fn undoes(&self) -> bool {
+        true
+    }
+    fn pending(&self, _: &Settings) -> bool {
+        self.pending
+    }
+    fn apply(&mut self, _: &mut Settings) -> Vec<Output> {
+        self.pending = false;
+        self.applied += 1;
+        vec![CHANGED]
+    }
+}
+
+/// A window of 854x960 (427x480 GUI px at its automatic scale) and one of 854x480 (427x240:
+/// the page list has room for six places).
+const TALL: [u32; 2] = [854, 960];
+const SHORT_WINDOW: [u32; 2] = [854, 480];
+
+/// One frame of `shell` in a window of `window`; the GUI size it was drawn at.
+fn drawn<S: Screen + Default>(shell: &mut Shell<S>, s: &Settings, window: [u32; 2]) -> (f32, f32) {
+    let mut batch = HudBatch::new(window);
+    shell.draw(s, &mut batch, &atlas(), (0.0, 0.0), false, None);
+    crate::widgets::end_frame(crate::widgets::generation() + 1);
+    (batch.width, batch.height)
+}
+
+fn middle([x, y, w, h]: [f32; 4]) -> (f32, f32) {
+    (x + w / 2.0, y + h / 2.0)
+}
+
+#[test]
+fn pages_that_fit_are_listed_and_more_collapse_into_one_row_leaving_none_out() {
+    let s = Settings::default();
+    let mut shell = Shell::<Pages>::default();
+    // Tall enough: each page under the last, the deeper page left out as it is in no list.
+    drawn(&mut shell, &s, TALL);
+    let tall = shell.page_places();
+    let pages: Vec<u8> = tall.iter().map(|p| p.0).collect();
+    assert_eq!(pages, (HOME..=PAGES).collect::<Vec<_>>());
+    assert!(tall.iter().all(|p| p.2 == Part::Tab));
+    assert!(tall.windows(2).all(|p| p[1].1[1] > p[0].1[1]));
+    assert_eq!(shell.strip_ends(), None);
+    // Short: the first page, then the section in one row, its first page between nothing and
+    // its next. Every place is inside the column, the row's on one line under the section's.
+    let size = drawn(&mut shell, &s, SHORT_WINDOW);
+    let short = shell.page_places();
+    let parts: Vec<(u8, Part)> = short.iter().map(|p| (p.0, p.2)).collect();
+    assert_eq!(
+        parts,
+        [(HOME, Part::Tab), (1, Part::Shown), (2, Part::Next)]
+    );
+    assert_eq!(shell.strip_ends(), Some((false, true)));
+    let cols = Columns::of(size.0, size.1);
+    for (_, [x, _, w, _], _) in &short {
+        assert!(*x >= cols.side_x && x + w <= cols.side_x + style::CONTROL_W);
+    }
+    assert_eq!(short[1].1[1], short[2].1[1]);
+    assert_eq!(short[1].1[1], cols.page(2)[1]);
+    // The line naming the section stays over it.
+    let labelled = crate::widgets::last_labelled();
+    let line = labelled.iter().find(|w| w.label == SECTION).unwrap();
+    assert!(line.y > cols.page(1)[1] && line.y < cols.page(2)[1]);
+}
+
+#[test]
+fn the_collapsed_rows_arrows_walk_every_page_and_its_ends_go_no_further() {
+    let mut s = Settings::default();
+    let mut shell = Shell::<Pages>::default();
+    shell.show(1);
+    let mut seen = vec![1];
+    let size = loop {
+        let size = drawn(&mut shell, &s, SHORT_WINDOW);
+        let places = shell.page_places();
+        let Some(&(next, rect, _)) = places.iter().find(|p| p.2 == Part::Next) else {
+            break size;
+        };
+        assert_eq!(
+            shell.click(&mut s, middle(rect), size, false, false, false),
+            [CLICK]
+        );
+        assert_eq!(shell.open_page(), Some(next));
+        seen.push(next);
+    };
+    assert_eq!(seen, (1..=PAGES).collect::<Vec<_>>());
+    assert_eq!(shell.strip_ends(), Some((true, false)));
+    // At the last page, the right of the row picks nothing: its arrow is dimmed.
+    let cols = Columns::of(size.0, size.1);
+    let [x, y, w, h] = cols.page(2);
+    assert!(
+        shell
+            .click(
+                &mut s,
+                (x + w - 2.0, y + h / 2.0),
+                size,
+                false,
+                false,
+                false
+            )
+            .is_empty()
+    );
+    assert_eq!(shell.open_page(), Some(PAGES));
+    // The page before it from the keyboard: Enter on its arrow opens it, and the focus follows
+    // it to the middle of the row.
+    let before = shell
+        .page_places()
+        .iter()
+        .find(|p| p.0 == PAGES - 1)
+        .unwrap()
+        .2;
+    assert_eq!(before, Part::Prev);
+    shell.set_focus(Some(Target::Page(PAGES - 1)));
+    assert_eq!(shell.key(&mut s, K::Enter, None, false, size), [CLICK]);
+    drawn(&mut shell, &s, SHORT_WINDOW);
+    let now = shell
+        .page_places()
+        .iter()
+        .find(|p| p.0 == PAGES - 1)
+        .unwrap()
+        .2;
+    assert_eq!(now, Part::Shown);
+}
+
+#[test]
+fn while_searching_the_collapsed_rows_arrows_skip_pages_without_matches() {
+    let mut s = Settings::default();
+    let mut shell = Shell::<Pages>::default();
+    // Rows 1, 10, 11 and 12: none before the first. The first page stays, as it has no match.
+    shell.set_search("row 1");
+    let size = drawn(&mut shell, &s, SHORT_WINDOW);
+    let pages = |shell: &Shell<Pages>| shell.page_places().iter().map(|p| p.0).collect::<Vec<_>>();
+    assert_eq!(pages(&shell), [HOME, 1, 10]);
+    assert_eq!(shell.strip_ends(), Some((false, true)));
+    // Its arrow goes to the next match, which has the first one before it and the last after.
+    let next = shell.page_places()[2].1;
+    shell.click(&mut s, middle(next), size, false, false, false);
+    drawn(&mut shell, &s, SHORT_WINDOW);
+    assert_eq!(pages(&shell), [HOME, 1, 10, 11]);
+    assert_eq!(shell.strip_ends(), Some((true, true)));
+}
+
+#[test]
+fn a_controllers_bumpers_find_the_collapsed_rows_parts_as_tabs() {
+    let s = Settings::default();
+    let mut shell = Shell::<Pages>::default();
+    shell.show(5);
+    drawn(&mut shell, &s, SHORT_WINDOW);
+    let tabs: Vec<(f32, bool)> = crate::widgets::last_targets()
+        .into_iter()
+        .filter_map(|t| match t.kind {
+            crate::widgets::Kind::Tab(open) => Some((t.rect[0], open)),
+            _ => None,
+        })
+        .collect();
+    // The first page, the page before, the open one (lit) and the one after.
+    assert_eq!(tabs.len(), 4, "{tabs:?}");
+    assert_eq!(tabs.iter().filter(|t| t.1).count(), 1);
+    let (before, open, after) = (tabs[1].0, tabs[2], tabs[3].0);
+    assert!(open.1 && before < open.0 && open.0 < after);
+    // The arrows are vanilla's Previous Page and Next Page to the narrator.
+    let labels = crate::widgets::last_labelled();
+    let named = |key| {
+        labels
+            .iter()
+            .any(|w| w.label == lang::get(key) && w.enabled)
+    };
+    assert!(named(PREVIOUS_PAGE) && named(NEXT_PAGE));
+}
+
+#[test]
+fn a_link_opens_a_page_out_of_the_list_and_escape_comes_back_to_the_links_page() {
+    let mut s = Settings::default();
+    let mut shell = Shell::<Pages>::default();
+    // Found by the search from another page: back is the page the link is on.
+    shell.show(HOME);
+    shell.set_search("deeper");
+    let at = shell.point_at(&s, SIZE, LINK);
+    assert_eq!(shell.click(&mut s, at, SIZE, false, false, false), [CLICK]);
+    // The page opens alone, the search cleared; the list lights the page the link was on.
+    assert_eq!(shell.open_page(), Some(DEEP));
+    assert_eq!(shell.listed(&s, SIZE), [(DEEP, u32::from(DEEP))]);
+    drawn(&mut shell, &s, TALL);
+    assert_eq!(shell.lit_page(), Some(1));
+    assert!(shell.key(&mut s, K::Escape, None, false, SIZE).is_empty());
+    assert_eq!(shell.open_page(), Some(1));
+    assert_eq!(
+        shell.key(&mut s, K::Escape, None, false, SIZE),
+        [Output::Done]
+    );
+}
+
+#[test]
+fn apply_shows_beside_undo_while_changes_wait_and_goes_with_them() {
+    let mut s = Settings::default();
+    let mut shell = Shell::<Pages>::default();
+    let done = Columns::of(SIZE.0, SIZE.1).button(0);
+    assert_eq!(shell.foot_at(&s, SIZE), [(Target::Done, done)]);
+    let at = shell.point_at(&s, SIZE, WAITS);
+    shell.click(&mut s, at, SIZE, false, false, false);
+    let foot = shell.foot_at(&s, SIZE);
+    let targets: Vec<_> = foot.iter().map(|f| f.0).collect();
+    assert_eq!(targets, [Target::Undo, Target::Apply, Target::Done]);
+    // Side by side over Done, as wide as it together.
+    let ([ux, uy, uw, _], [ax, ay, aw, _]) = (foot[0].1, foot[1].1);
+    assert_eq!((uy, ay), (foot[2].1[1] - FOOT_GAP - style::BUTTON_H, uy));
+    assert!(ux + uw < ax && ax + aw == done[0] + done[2] && ux == done[0]);
+    assert_eq!(
+        shell.click(&mut s, middle(foot[1].1), SIZE, false, false, false),
+        [CLICK, CHANGED]
+    );
+    assert_eq!(shell.screen.applied, 1);
+    let targets: Vec<_> = shell.foot_at(&s, SIZE).iter().map(|f| f.0).collect();
+    assert_eq!(targets, [Target::Undo, Target::Done]);
+}
+
+#[test]
+fn the_right_button_steps_no_choice_as_vanillas_cycle_button() {
+    let mut s = Settings::default();
+    let mut shell = Shell::<Probe>::default();
+    let choice = middle_of(&mut shell, CHOICE, SIZE);
+    assert!(
+        shell
+            .click(&mut s, choice, SIZE, false, true, false)
+            .is_empty()
+    );
+    assert!(shell.screen.pressed.is_empty());
+}
@@ -192,7 +192,12 @@ impl SignData {
        let side = |t: Option<&Tag>| -> SignText {
            let mut out = SignText::default();
            let Some(t) = t else { return out };
-            if let Some(Tag::List(messages)) = t.get("messages") {
+            if let Some(messages) = t.get("messages") {
+                // `SignText.CODEC` reads a side all or nothing: a messages
+                // field that is not a list leaves the side empty.
+                let Tag::List(messages) = messages else {
+                    return SignText::default();
+                };
                for (i, m) in messages.iter().take(4).enumerate() {
                    out.lines[i] = component_text(m);
                    out.click[i] = click_event(m);
@@ -307,6 +312,27 @@ pub fn editor_sprite(folder: &str, wood: &str) -> String {
 #[cfg(test)]
 mod tests {
    use super::*;
+    /// `SignText.CODEC` reads messages as a list: a string field fails the
+    /// whole side, taking its colour and glow with it.
+    #[test]
+    fn messages_that_are_not_a_list_load_an_empty_side() {
+        let tag = Tag::compound([(
+            "front_text",
+            Tag::compound([
+                ("messages", Tag::String("not a list".into())),
+                ("color", Tag::String("red".into())),
+                ("has_glowing_text", Tag::Byte(1)),
+            ]),
+        )]);
+        let mut decoded = SignData::default();
+        decoded.decode(&tag);
+        assert_eq!(
+            decoded.front,
+            SignText::default(),
+            "a failed message list takes the side's colour and glow with it"
+        );
+    }
+
    #[test]
    fn waxed_and_glowing_text_take_any_number() {
        let tag = Tag::compound([
@@ -913,6 +913,20 @@ pub trait Backend {
    fn unpause(&mut self, channel: ChannelId);
    /// `Channel.stopped`.
    fn stopped(&mut self, channel: ChannelId) -> bool;
+    /// Update volume, pitch, and position in a single backend call.
+    fn update_channel(&mut self, channel: ChannelId, volume: f32, pitch: f32, position: [f64; 3]) {
+        self.set_volume(channel, volume);
+        self.set_pitch(channel, pitch);
+        self.set_position(channel, position);
+    }
+    /// Filter which handles have stopped playing in a single pass.
+    fn filter_stopped(&mut self, live: &[(u64, ChannelId)], stopped: &mut Vec<u64>) {
+        for &(h, c) in live {
+            if self.stopped(c) {
+                stopped.push(h);
+            }
+        }
+    }
    /// Whether the channel plays clearly through a mod's muffle (`Audio::muffle`): its sound
    /// event is one the mod exempted. A backend without a muffle ignores it.
    fn set_unmuffled(&mut self, _channel: ChannelId, _unmuffled: bool) {}
@@ -1494,13 +1508,14 @@ impl SoundEngine {
                .iter()
                .filter_map(|(h, handle)| handle.channel.map(|c| (*h, c))),
        );
-        for (h, c) in live.drain(..) {
-            if backend.stopped(c) {
-                self.release_handle(h, backend);
-            }
+        let mut stopped = std::mem::take(&mut self.mapped_scratch);
+        stopped.clear();
+        backend.filter_stopped(&live, &mut stopped);
+        for h in stopped.drain(..) {
+            self.release_handle(h, backend);
        }
        // Released handles nobody maps any more.
-        let mut mapped = std::mem::take(&mut self.mapped_scratch);
+        let mut mapped = stopped;
        mapped.clear();
        mapped.extend(self.instance_to_channel.iter().map(|(_, h)| *h));
        self.handles
@@ -1550,9 +1565,7 @@ impl SoundEngine {
                h.pitch_edited = pitch_edited;
            }
            if let Some(c) = self.handles.get(&handle).and_then(handle_channel) {
-                backend.set_volume(c, volume);
-                backend.set_pitch(c, pitch);
-                backend.set_position(c, position);
+                backend.update_channel(c, volume, pitch, position);
            }
            let instance = self.instances.get_mut(&id).expect("present");
            if instance.looping
@@ -304,19 +304,19 @@ impl StudioUi {

                // Card background & highlight
                if is_selected {
-                    style::fill(batch, atlas, rect, style::OPEN);
+                    style::fill(batch, atlas, rect, style::open());
                } else if is_hovered {
-                    style::fill(batch, atlas, rect, style::HOVER);
+                    style::fill(batch, atlas, rect, style::hover());
                } else {
                    style::well(batch, atlas, rect);
                }

                let border_color = if is_selected {
-                    style::ACCENT
+                    style::accent()
                } else if is_hovered {
                    style::WHITE
                } else {
-                    style::ROW_RULE
+                    style::row_rule()
                };
                style::ring(batch, atlas, rect, border_color);

@@ -1238,6 +1238,9 @@ pub struct EditBox {
    /// Grey completion shown after the text (EditBox.setSuggestion).
    pub suggestion: Option<String>,
    pub text_color: u32,
+    /// `EditBox.setCentered`: the text starts in the middle of the box's
+    /// width, not at its left edge (`BookSignScreen`'s title).
+    pub centered: bool,
    /// `EditBox.textColorUneditable`: the colour of a box `setEditable(false)`
    /// made read-only, which still shows its value and caret.
    pub text_color_uneditable: u32,
@@ -1248,6 +1251,9 @@ pub struct EditBox {
    /// `getMessage`: what the narrator calls the box ("<message> edit box:
    /// <value>").
    pub message: String,
+    /// `EditBox.setInvertHighlightedTextColor`: a selection draws its text
+    /// inverted (the default) or in the box's own colour (`AnvilScreen`).
+    pub invert_highlighted_text_color: bool,
    /// Where a borderless box drawn in a frame of its own focuses: a controller's outline goes
    /// round the frame, not over the text.
    pub frame: Option<[f32; 4]>,
@@ -1536,9 +1542,11 @@ impl EditBox {
            focused_at: Instant::now(),
            suggestion: None,
            text_color: rgba(224, 224, 224, 255),
+            centered: false,
            text_color_uneditable: rgba(112, 112, 112, 255),
            editable: true,
            message: String::new(),
+            invert_highlighted_text_color: true,
            frame: None,
        }
    }
@@ -1559,6 +1567,16 @@ impl EditBox {
            self.y
        }
    }
+    /// `EditBox.updateTextPosition`: where the text starts, `(width - text
+    /// width) / 2` in for a centred box (vanilla's `textX`), else at
+    /// `text_x` (4 in from a border).
+    pub fn text_start_x(&self, text_width: f32) -> f32 {
+        if self.centered {
+            self.x + ((self.width - text_width) / 2.0).floor()
+        } else {
+            self.text_x()
+        }
+    }
    pub fn reset_blink(&mut self) {
        self.focused_at = Instant::now();
    }
@@ -1641,8 +1659,13 @@ impl EditBox {
    /// EditBox.findClickedPositionInText: the character boundary under GUI `x`.
    pub fn position_at(&mut self, atlas: &HudAtlas, x: f32) -> usize {
        self.layout(atlas);
-        let room = (x.floor() - self.text_x()).min(self.inner_width());
        let rest: String = self.value.chars().skip(self.display).collect();
+        let shown: String = rest
+            .chars()
+            .take(atlas.font.fit(&rest, self.inner_width()))
+            .collect();
+        let start = self.text_start_x(atlas.font.width_text(&Text::literal(shown.as_str())));
+        let room = (x.floor() - start).min(self.inner_width());
        self.display + atlas.font.fit(&rest, room)
    }
    /// EditBox.onClick: the cursor to the pointer, extending the selection
@@ -1849,7 +1872,12 @@ impl EditBox {
                ),
            }
        };
-        let (tx, ty) = (self.text_x(), self.text_y());
+        let start = if self.centered {
+            self.text_start_x(atlas.font.width_text(&Text::literal(displayed.as_str())))
+        } else {
+            self.text_x()
+        };
+        let (tx, ty) = (start, self.text_y());
        let mut draw_x = tx;
        if !displayed.is_empty() {
            let half = if on_screen {
@@ -1894,7 +1922,11 @@ impl EditBox {
            let right = self.x + self.width;
            let (x0, x1) = (cursor_x.min(right), (hx - 1.0).min(right));
            let (a, b) = (x0.min(x1), x0.max(x1));
-            batch.text_highlight(atlas, (a, ty - 1.0, b - a, 11.0), true);
+            batch.text_highlight(
+                atlas,
+                (a, ty - 1.0, b - a, 11.0),
+                self.invert_highlighted_text_color,
+            );
        }
        if show_cursor {
            if insert {
@@ -2604,6 +2636,20 @@ mod tests {
        );
    }

+    /// `EditBox.setInvertHighlightedTextColor`: a selection inverts its text
+    /// unless the box asks it not to (the anvil's rename box).
+    #[test]
+    fn a_selection_inverts_its_text_unless_the_box_says_not_to() {
+        let mut edit = EditBox::new(0.0, 0.0, 100.0, 20.0);
+        assert!(edit.invert_highlighted_text_color);
+        edit.invert_highlighted_text_color = false;
+        edit.set_value("name");
+        edit.set_cursor(0, false);
+        edit.set_cursor(4, true);
+        assert_eq!(edit.selected_text(), "name");
+        assert!(!edit.invert_highlighted_text_color);
+    }
+
    /// `EditBox.setEditable(false)`: the box keeps the focus, the caret keys
    /// and copy, but `charTyped`/paste/Backspace/Delete do nothing, and Cut
    /// copies without taking the text out. A value and the caret still show,
@@ -2650,4 +2696,19 @@ mod tests {
        assert!(edit.key(winit::keyboard::KeyCode::Backspace, false, false));
        assert_eq!(edit.value, "name");
    }
+
+    /// `EditBox.setCentered` (`BookSignScreen`'s title box): with the flag the
+    /// text starts `(width - text width) / 2` in, which is also where a click
+    /// maps; without it the text starts at the box's left edge.
+    #[test]
+    fn a_centred_box_starts_its_text_in_the_middle() {
+        let mut edit = EditBox::new(10.0, 0.0, 114.0, 9.0);
+        edit.bordered = false;
+        assert_eq!(edit.text_start_x(0.0), 10.0);
+        edit.centered = true;
+        assert_eq!(edit.text_start_x(0.0), 67.0);
+        assert_eq!(edit.text_start_x(18.0), 58.0);
+        // (114 - 5) / 2 = 54.5, rounded down.
+        assert_eq!(edit.text_start_x(5.0), 64.0);
+    }
 }
@@ -119,15 +119,14 @@ audio = ["horizon-client-render/audio", "horizon-client-lib/audio"]
 controllers = ["horizon-client-lib/controllers", "dep:gilrs", "dep:horizon-dualsense", "horizon-client-input/controllers"]
 # Horizon's own extras over the vanilla game, for a fork that wants them out (docs/forking.md):
 # cosmetics and emotes, the "Horizon player" presence, the official server added to
-# the server list, the Horizon Settings and Mods pages, Discord and Play with Friends. Players always get them; there is no switch. `grep -rn horizon-extras crates/` lists
+# the server list, the Horizon Settings and Mods pages and Play with Friends, and ray tracing on
+# request (`HORIZON_RAY_TRACING=1`). Players always get them; there is no switch. `grep -rn horizon-extras crates/` lists
 # every place it gates. Without it (`--no-default-features --features audio,controllers`) the
 # client is best effort: CI builds only the default.
-horizon-extras = ["discord", "friends"]
-# Online extras a server or a port can leave out; the server build has none of them. "Playing Horizon"
-# on Discord (game/discord.rs).
-discord = ["horizon-client-lib/discord"]
-# Play with Friends: sharing a world behind an invite code (game/friends.rs) and joining one.
-friends = ["horizon-client-lib/friends", "dep:horizon-friends"]
+horizon-extras = ["horizon-client-render/horizon-extras", "friends"]
+# Play with Friends: sharing a world behind an invite code (game/friends.rs). Joining one is
+# horizon-friends' `game` side, which horizon-official registers (`horizon_hooks::tunnel`).
+friends = ["dep:horizon-friends"]
 # Records the call sites of mob random draws (`mob_ai_probe` traces).
 rng-trace = ["horizon-core/rng-trace", "horizon-client-lib/rng-trace"]
 # Rust's allocations go to the system heap instead of mimalloc, where heap profilers that replace
@@ -11,6 +11,18 @@
  "horizon.options.gameplay_guide.basic": "Basic",
  "horizon.options.gameplay_guide.full": "Full",
  "horizon.options.gameplay_guide.off": "Off",
+  "horizon.options.radial_mode": "Radial Menu",
+  "horizon.options.radial_mode.about": "Hold the opener for the radial menu, or press it once to open it and again to close it.",
+  "horizon.options.radial_mode.hold.about": "Hold the opener and let go to run what the stick points at.",
+  "horizon.options.radial_mode.toggle.about": "Press the opener to open it; A or the opener again runs what the stick points at, B closes it.",
+  "horizon.options.radial_stick": "Radial Menu Selects With",
+  "horizon.options.radial_stick.about": "The stick that points at the radial menu's slots.",
+  "horizon.options.radial_stick.right": "Right Stick",
+  "horizon.options.radial_stick.left": "Left Stick",
+  "horizon.options.radial_stick.either": "Either",
+  "horizon.options.radial_stick.right.about": "The right stick points at the slots; the left still walks.",
+  "horizon.options.radial_stick.left.about": "The left stick points and you stand still. D-pad Right is under that thumb: pick an opener on the Radial Menu page.",
+  "horizon.options.radial_stick.either.about": "The last stick pushed points; neither walks nor turns the view. Only a bumper, a trigger or View can open the menu.",
  "horizon.controller.guide.use": "Use",
  "horizon.controller.guide.open": "Open",
  "horizon.controller.guide.ride": "Ride",
@@ -129,6 +141,82 @@
  "horizon.pages.shader_options": "Shader Options",
  "horizon.pages.controller": "Controller Settings",
  "horizon.pages.controller_binds": "Controller Binds",
+  "horizon.pages.controller_radial": "Radial Menu",
+  "horizon.radial.page.general": "General",
+  "horizon.radial.page.camera": "Camera",
+  "horizon.radial.release_stick": "Let go of the stick",
+  "horizon.radial.action.key_inventory": "Inventory",
+  "horizon.radial.action.key_chat": "Chat",
+  "horizon.radial.action.key_command": "Commands",
+  "horizon.radial.action.key_advancements": "Advancements",
+  "horizon.radial.action.key_togglePerspective": "Perspective",
+  "horizon.radial.action.key_swapOffhand": "Swap Hands",
+  "horizon.radial.action.key_drop": "Drop",
+  "horizon.radial.action.key_pickItem": "Pick Block",
+  "horizon.radial.action.key_screenshot": "Screenshot",
+  "horizon.radial.action.key_toggleGui": "Hide HUD",
+  "horizon.radial.action.key_smoothCamera": "Cinematic Camera",
+  "horizon.radial.action.key_socialInteractions": "Social",
+  "horizon.radial.action.key_emote": "Emote",
+  "horizon.radial.action.pad_hotbarPrevious": "Previous Slot",
+  "horizon.radial.action.pad_hotbarNext": "Next Slot",
+  "horizon.radial.action.key_fullscreen": "Fullscreen",
+  "horizon.radial.action.key_quickActions": "Quick Actions",
+  "horizon.radial.action.key_debug_overlay": "Debug Screen",
+  "horizon.radial.missing": "Missing",
+  "horizon.radial.why.missing": "Unknown action",
+  "horizon.radial.why.cosmetics": "Needs cosmetics on",
+  "horizon.radial.why.quick_actions": "This server has no Quick Actions",
+  "horizon.radial.why.social": "Only on a server",
+  "horizon.radial.next": "→ %s",
+  "horizon.radial.state.first_person": "First Person",
+  "horizon.radial.state.third_person_back": "Third Person",
+  "horizon.radial.state.third_person_front": "Front View",
+  "horizon.radial.state.shown": "Shown",
+  "horizon.radial.state.hidden": "Hidden",
+  "horizon.radial.state.on": "On",
+  "horizon.radial.state.off": "Off",
+  "horizon.radial.pick_title": "Choose an Action",
+  "horizon.radial.group.actions": "Actions",
+  "horizon.radial.pick.slot": "%s slot of %s",
+  "horizon.radial.pick.about": "Puts this action in the slot and goes back. The slot's own is marked.",
+  "horizon.radial.pick.current": "Current",
+  "horizon.radial.missing.about": "This game doesn't know the action %s: the slot keeps it and runs nothing. Press or Right to put another here.",
+  "horizon.radial.page.new": "New Page",
+  "horizon.pages.open.controller_radial": "Radial Menu...",
+  "horizon.radial.group.slots": "Slots",
+  "horizon.radial.group.page": "Page",
+  "horizon.radial.group.all": "All Pages",
+  "horizon.radial.empty": "Empty",
+  "horizon.radial.page_of": "Page %s of %s. Each slot is a direction of the selecting stick while the opener is held.",
+  "horizon.radial.slot.0": "Up",
+  "horizon.radial.slot.1": "Up-Right",
+  "horizon.radial.slot.2": "Right",
+  "horizon.radial.slot.3": "Down-Right",
+  "horizon.radial.slot.4": "Down",
+  "horizon.radial.slot.5": "Down-Left",
+  "horizon.radial.slot.6": "Left",
+  "horizon.radial.slot.7": "Up-Left",
+  "horizon.radial.slot.about": "The action this direction runs. Press it for the list of actions, Right for the next one, Left or Shift-click for the one before.",
+  "horizon.radial.rename": "Rename Page",
+  "horizon.radial.rename.about": "Give this page a name of your own.",
+  "horizon.radial.name_title": "Name This Page",
+  "horizon.radial.new_page.about": "Adds an empty page after the last one, and shows it.",
+  "horizon.radial.new_page.full": "The menu holds at most %s pages.",
+  "horizon.radial.delete_page": "Delete Page",
+  "horizon.radial.delete_page.about": "Removes this page and its slots at once. Undo brings it back.",
+  "horizon.radial.delete_page.last": "The menu keeps at least one page.",
+  "horizon.radial.reset": "Reset All Pages",
+  "horizon.radial.reset.about": "Puts back the General and Camera pages and removes the rest, at once. Undo brings them back.",
+  "horizon.radial.reset.default": "The pages are the defaults already.",
+  "horizon.radial.opener": "Opener",
+  "horizon.radial.opener.about": "The button held to open the menu. Press, then press the controller button to use: a bumper or the D-pad, not A, B, X, Y or the right stick, which steer and cancel.",
+  "horizon.radial.opener.about.left": "The button held to open the menu. Press, then press the controller button to use: a bumper, A, X or Y, not the D-pad or the left stick, which steer, nor B, which cancels.",
+  "horizon.radial.opener.about.either": "The button held to open the menu. Press, then press the controller button to use: a bumper, a trigger or View; both thumbs steer, and B cancels.",
+  "horizon.radial.unbound": "No button opens the menu (one under the thumb that selects is let go): press, then press a controller button.",
+  "horizon.radial.conflict": "Shared with another action: in play the menu takes that button. Press to pick another.",
+  "Radial Menu": "Radial Menu",
+  "Named pages of eight actions, held open with a button.": "Named pages of eight actions, held open with a button.",
  "horizon.pages.extras": "Horizon Extras",
  "horizon.pages.settings": "Horizon Settings",
  "horizon.pages.studio": "Replay Studio",
@@ -287,6 +375,7 @@
  "This feature is not yet available in Horizon.": "This feature is not yet available in Horizon.",
  "Your display or system doesn't offer HDR output.": "Your display or system doesn't offer HDR output.",
  "Turn HDR on to use it.": "Turn HDR on to use it.",
+  "The shader pack lights the world itself.": "The shader pack lights the world itself.",
  "Your GPU or graphics API doesn't support it.": "Your GPU or graphics API doesn't support it.",
  "Not with software rendering, which runs it on the CPU.": "Not with software rendering, which runs it on the CPU.",
  "Out of video memory: off until the next start.": "Out of video memory: off until the next start.",
@@ -441,6 +530,7 @@
  "HDR Calibration %s/%s: %s": "HDR Calibration %s/%s: %s",
  "Sets the three below full screen, one test picture at a time.": "Sets the three below full screen, one test picture at a time.",
  "Your display didn't say how bright it gets: calibrate to set it up.": "Your display didn't say how bright it gets: calibrate to set it up.",
+  "Your display's reported peak is often too high: calibrate to set it up.": "Your display's reported peak is often too high: calibrate to set it up.",
  "Already set up for your display. Only calibrate if HDR looks wrong.": "Already set up for your display. Only calibrate if HDR looks wrong.",
  "Puts Peak Brightness and Paper White back to your display's setup.": "Puts Peak Brightness and Paper White back to your display's setup.",
  "Set up for your display. Leave on Auto unless it looks wrong.": "Set up for your display. Leave on Auto unless it looks wrong.",
@@ -1018,6 +1108,7 @@
  "Press the button for this. %s cancels.": "Press the button for this. %s cancels.",
  "This button also does: %s": "This button also does: %s",
  "Not bound: press this row, then the button that should do it.": "Not bound: press this row, then the button that should do it.",
+  "horizon.pad.action.radial": "Radial Menu",
  "horizon.pad.notice.connected.press": "Press to use it",
  "horizon.recipe_transfer.missing": "Missing Items",
  "horizon.recipe_transfer.no_room": "Inventory full",
@@ -97,6 +97,7 @@ pub fn main() -> Result<()> {
        facts: &facts,
        collision: &collision,
        player: None,
+        cached_chunk: std::cell::Cell::new(None),
    };
    let mut engine = ParticleEngine::new(&root, &Default::default(), &Default::default());
    let mut out = BufWriter::new(File::create(&args[2])?);
@@ -194,6 +194,7 @@ pub fn main() -> Result<()> {
            facts: &facts,
            collision: &collision,
            player: None,
+            cached_chunk: std::cell::Cell::new(None),
        };
        let v = |key: &str| -> [f64; 3] {
            std::array::from_fn(|i| case[key][i].as_f64().unwrap_or(0.0))