rustfmt

Co-Authored-By: Claude Opus 5.5 <[email protected]>

Cargo.lock

@@ -1650,6 +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"
@@ -1793,14 +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"

Cargo.toml

@@ -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",

crates/horizon-addresses/src/lib.rs

@@ -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";

crates/horizon-client-lib/Cargo.toml

@@ -109,17 +109,12 @@ objc2-foundation = { version = "0.3", default-features = false, features = ["std
 wgpu = { version = "30.0.1", default-features = false, features = ["gles"] }
 
 [features]
-default = ["audio", "controllers", "horizon-extras"]
+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"]
-# Horizon's own parts (docs/forking.md, docs/layers.md): the features below, and the official
-# server in the list (`official_servers`).
-horizon-extras = ["discord"]
-# "Playing Horizon" on the player's Discord profile (`discord_presence`).
-discord = []
 # 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.

crates/horizon-client-render/src/extras.rs

@@ -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));

crates/horizon-client-render/src/gfx.rs

@@ -239,6 +239,7 @@ mod reuse;
 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 +251,7 @@ 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 +728,6 @@ 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
@@ -10116,7 +10062,11 @@ 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

crates/horizon-client-render/src/gfx/off_page.rs

@@ -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
+}

crates/horizon-client-render/src/options_ui_pages.rs

@@ -124,21 +124,15 @@ 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
     }

crates/horizon-client/Cargo.toml

@@ -119,13 +119,10 @@ 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. 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 = ["horizon-client-lib/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"]
+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"]

crates/horizon-client/src/client_lib.rs

@@ -58,8 +58,6 @@ pub mod debug_overlay;
 pub mod debugworld;
 pub mod dialog;
 pub mod dialog_screen;
-#[cfg(feature = "discord")]
-pub mod discord_presence;
 pub mod end_crystal;
 pub mod end_gateway;
 pub mod entities;
@@ -102,8 +100,6 @@ pub mod native_data;
 pub mod net;
 pub mod nether_portal;
 pub mod no_resources;
-#[cfg(feature = "horizon-extras")]
-pub mod official_servers;
 pub mod offline_name;
 pub mod old_world;
 pub mod osk;

crates/horizon-client/src/game.rs

@@ -49,6 +49,7 @@ fn pack_files(world_tables: &Option<WorldTables>) -> horizon_world::loot::PackOv
     }
 }
 
+mod activity;
 mod advancements;
 mod advancements_screen;
 mod agent;
@@ -128,8 +129,6 @@ mod decorated_pot;
 mod dedicated;
 mod deflect;
 mod dialogs;
-#[cfg(feature = "discord")]
-mod discord;
 mod dispense_fixture;
 mod dispenser;
 mod dragon;
@@ -6475,18 +6474,6 @@ impl Game<'_> {
             self.draw_tooltip_lines(batch, &lines, self.cursor.0, self.cursor.1);
         }
     }
-    /// `AbstractContainerScreen` keeps `isQuickCrafting` and the drag it
-    /// belongs to on the screen. Horizon keeps both on `Game` (`inv_clicks`,
-    /// `inv_drag`, `last_inv_click`), so they are dropped when the pointer
-    /// changes hands: a screen that opens or closes starts with its own
-    /// state, and a press whose release never reached the screen -- the
-    /// pointer left the window, or the screen closed first -- would
-    /// otherwise leave every later press on every later screen swallowed.
-    pub(super) fn reset_inventory_clicks(&mut self) {
-        self.inv_clicks.cancel_drag();
-        self.inv_drag = None;
-        self.last_inv_click = None;
-    }
     pub(super) fn close_container(&mut self) {
         // `Gui.setScreen` clears the old screen's focus before it goes: the
         // key that closed the container (Tab bound to the inventory) has
@@ -6530,20 +6517,6 @@ impl Game<'_> {
         }
         self.close_ender_chest();
     }
-    /// A sound a menu click made the player play (a bundle's insert or
-    /// remove): `Entity.playSound` at the player.
-    pub(super) fn player_menu_sound(&mut self, sound: &str) {
-        let Some(p) = self.player.as_ref() else {
-            return;
-        };
-        let at = [p.position.x, p.position.y, p.position.z];
-        let (volume, pitch) = if sound == horizon_client::bundle::INSERT_FAIL {
-            (1.0, 1.0)
-        } else {
-            (0.8, 0.8 + self.world.random.next_float() * 0.4)
-        };
-        self.audio.play(sound, Some(at), volume, pitch);
-    }
     /// `Camera.setRotation`: the camera's orientation, turned round in
     /// third-person front view.
     pub(super) fn camera_orientation(&self) -> glam::Quat {
@@ -11430,8 +11403,7 @@ impl Game<'_> {
                     self.heal_hold_latches();
                     // For the hooks above the engine (the "I'm playing" ping): said when it changes.
                     horizon_hooks::engine::published(self.is_published());
-                    #[cfg(feature = "discord")]
-                    self.update_discord_presence();
+                    self.report_activity();
                     let steps = self.clock.advance(elapsed);
                     for _ in 0..steps {
                         let started = Instant::now();
@@ -12691,10 +12663,8 @@ pub fn run_with() -> Result<()> {
     // horizon-ctl drives: those start in a source checkout and wrote the list there.
     if !options.offscreen && !synchronous_startup(&options) {
         let version = horizon_client::telemetry::version();
-        horizon_hooks::engine::started(&horizon_hooks::Started::new(&version));
-        // horizon-extras: the official server is Horizon's (docs/forking.md).
-        #[cfg(feature = "horizon-extras")]
-        horizon_client::official_servers::update(&horizon_client::logging::player_dir());
+        let game_dir = horizon_client::logging::player_dir();
+        horizon_hooks::engine::started(&horizon_hooks::Started::new(&version, &game_dir));
     }
     mods::register_components(&vanilla_root)?;
     mods::register_standalone_models();
@@ -12722,15 +12692,8 @@ pub fn run_with() -> Result<()> {
     if options.execution_role.is_client() {
         narrator::start(&early_settings);
     }
-    // "Playing Horizon" on Discord: never for a server; an automated run only talks to a test's fake Discord.
-    #[cfg(feature = "discord")]
-    if options.dedicated.is_none() {
-        let automated = options.benchmark.is_some()
-            || options.offscreen
-            || options.frames.is_some()
-            || options.world_frames.is_some();
-        horizon_client::discord_presence::start(early_settings.extras.discord_presence, automated);
-    }
+    // A game window's hooks (Discord's presence): never for a server.
+    activity::client_started(&options);
     // Snapshots of derived tables live in the game folder, never beside the
     // shared resources.
     Behaviours::set_cache_dir(std::env::current_dir()?.join(".horizon-cache"));

crates/horizon-client/src/game/activity.rs

@@ -0,0 +1,68 @@
+//! What the player is doing, for the hooks above the engine (`Hooks::activity`: the Horizon
+//! layer's Discord presence shows it).
+use super::*;
+use horizon_client::command::args::GameMode;
+use horizon_hooks::{Activity, Client, Dimension, Play};
+
+/// At startup, for a game window (never a dedicated server's): the player's first activity, then
+/// `Hooks::client_started`.
+pub(super) fn client_started(options: &Options) {
+    if options.dedicated.is_some() {
+        return;
+    }
+    let automated = options.benchmark.is_some()
+        || options.offscreen
+        || options.frames.is_some()
+        || options.world_frames.is_some();
+    horizon_hooks::engine::activity(Activity::Menus);
+    horizon_hooks::engine::client_started(&Client::new(automated));
+}
+
+impl Game<'_> {
+    /// Each frame: only a change reaches the hooks.
+    pub(super) fn report_activity(&self) {
+        // One status per computer: P1's, not a splitscreen player's.
+        if self.options.split_guest {
+            return;
+        }
+        horizon_hooks::engine::activity(self.activity());
+    }
+    fn activity(&self) -> Activity {
+        if self.title.is_some() {
+            return Activity::Menus;
+        }
+        let max = horizon_client::lan::MAX_PLAYERS;
+        let play = if let Some(host) = &self.lan {
+            Play::Hosting {
+                players: 1 + host.hub.guests.len(),
+                max,
+            }
+        } else if let Some(server) = &self.integrated {
+            match (server.published(), &self.remote) {
+                (Some(_), Some(remote)) => Play::Hosting {
+                    players: remote.player_count(),
+                    max,
+                },
+                _ => Play::Singleplayer,
+            }
+        } else if self.remote.is_some() {
+            Play::Multiplayer
+        } else {
+            Play::Singleplayer
+        };
+        Activity::World {
+            play,
+            dimension: match self.dim {
+                Dim::Overworld => Dimension::Overworld,
+                Dim::Nether => Dimension::Nether,
+                Dim::End => Dimension::End,
+            },
+            mode: match self.mode {
+                GameMode::Survival => horizon_hooks::GameMode::Survival,
+                GameMode::Creative => horizon_hooks::GameMode::Creative,
+                GameMode::Adventure => horizon_hooks::GameMode::Adventure,
+                GameMode::Spectator => horizon_hooks::GameMode::Spectator,
+            },
+        }
+    }
+}

crates/horizon-client/src/game/discord.rs

@@ -1,49 +0,0 @@
-//! What the player is doing, for Discord Rich Presence (`horizon_client::discord_presence`).
-use super::*;
-use horizon_client::discord_presence::{self as presence, Dimension, Play, Status};
-
-impl Game<'_> {
-    /// Each frame: only a change reaches the presence thread.
-    pub(super) fn update_discord_presence(&self) {
-        // One Discord status per computer: P1's, not a splitscreen player's.
-        if self.options.split_guest {
-            return;
-        }
-        presence::set(self.discord_status());
-    }
-    fn discord_status(&self) -> Status {
-        if !self.settings.extras.discord_presence {
-            return Status::Off;
-        }
-        if self.title.is_some() {
-            return Status::Menus;
-        }
-        let play = if let Some(host) = &self.lan {
-            Play::Hosting {
-                players: 1 + host.hub.guests.len(),
-                max: horizon_client::lan::MAX_PLAYERS,
-            }
-        } else if let Some(server) = &self.integrated {
-            match (server.published(), &self.remote) {
-                (Some(_), Some(remote)) => Play::Hosting {
-                    players: remote.player_count(),
-                    max: horizon_client::lan::MAX_PLAYERS,
-                },
-                _ => Play::Singleplayer,
-            }
-        } else if self.remote.is_some() {
-            Play::Multiplayer
-        } else {
-            Play::Singleplayer
-        };
-        Status::World {
-            play,
-            dimension: match self.dim {
-                Dim::Overworld => Dimension::Overworld,
-                Dim::Nether => Dimension::Nether,
-                Dim::End => Dimension::End,
-            },
-            mode: self.mode,
-        }
-    }
-}

crates/horizon-client/src/game/loading_screen.rs

@@ -34,8 +34,6 @@ pub(super) fn run_event_loop(mut game: Game<'_>) -> Result<()> {
     narrator::stop();
     leave_fullscreen_after(&result, &mut game.settings);
     result?;
-    #[cfg(feature = "discord")]
-    horizon_client::discord_presence::stop();
     write_report(&game)?;
     if let Some(e) = game.error.take() {
         return Err(e);

crates/horizon-client/src/game/menu_clicks.rs

@@ -899,4 +899,32 @@ impl Game<'_> {
             f.input_clicked(world_recipes!(self), before);
         }
     }
+
+    /// `AbstractContainerScreen` keeps `isQuickCrafting` and the drag it
+    /// belongs to on the screen. Horizon keeps both on `Game` (`inv_clicks`,
+    /// `inv_drag`, `last_inv_click`), so they are dropped when the pointer
+    /// changes hands: a screen that opens or closes starts with its own
+    /// state, and a press whose release never reached the screen -- the
+    /// pointer left the window, or the screen closed first -- would
+    /// otherwise leave every later press on every later screen swallowed.
+    pub(super) fn reset_inventory_clicks(&mut self) {
+        self.inv_clicks.cancel_drag();
+        self.inv_drag = None;
+        self.last_inv_click = None;
+    }
+
+    /// A sound a menu click made the player play (a bundle's insert or
+    /// remove): `Entity.playSound` at the player.
+    pub(super) fn player_menu_sound(&mut self, sound: &str) {
+        let Some(p) = self.player.as_ref() else {
+            return;
+        };
+        let at = [p.position.x, p.position.y, p.position.z];
+        let (volume, pitch) = if sound == horizon_client::bundle::INSERT_FAIL {
+            (1.0, 1.0)
+        } else {
+            (0.8, 0.8 + self.world.random.next_float() * 0.4)
+        };
+        self.audio.play(sound, Some(at), volume, pitch);
+    }
 }

crates/horizon-client/src/game/minecarts.rs

@@ -28,6 +28,10 @@ use horizon_core::{
 };
 use horizon_world::registry::BlockStateId;
 use std::{collections::HashMap, sync::Arc};
+mod index;
+mod nbt;
+pub(super) use index::CartIndex;
+use index::cart_at;
 
 #[derive(Clone, Copy, Debug, PartialEq, Eq, Hash)]
 pub(super) enum CartKind {
@@ -187,102 +191,6 @@ pub(super) const TNT_PRIME_EVENT: i8 = 70;
 mod display;
 use display::{cart_render_bounds, display_offset, shown_unless_air};
 pub(super) use display::{default_display_offset, forget_unreadable_display};
-/// The carts' and mobs' boxes for one tick's cart pushes (`push_from_cart`,
-/// `pickup_from_cart`), so a cart reads its neighbours instead of every cart and
-/// every mob of the level. Both answer in slot order, as the scans did.
-///
-/// The cart grid follows each ticked cart ([`CartIndex::moved`]); it is
-/// rebuilt once the list's length changed (a cart gone or added), and dropped
-/// after a command, which can move or replace any cart
-/// ([`CartIndex::forget_carts`]). The mob grid holds until the mob
-/// list's next write ([`ListStamp`]). A native mod's hook can move either kind
-/// unseen, so with mods loaded both scans stay.
-#[derive(Default)]
-pub(super) struct CartIndex {
-    carts: Option<(SeenGrid, Vec<u32>)>,
-    /// The grid, and the carts a mob rides.
-    mobs: Option<(ListStamp, SeenGrid, FxHashSet<u32>)>,
-    near: Vec<u32>,
-}
-impl CartIndex {
-    fn usable() -> bool {
-        horizon_client::mod_api::mods().is_empty()
-    }
-    /// The cart in slot `i` has these bounds now.
-    fn moved(&mut self, i: usize, bounds: Aabb) {
-        if let Some((grid, ids)) = &mut self.carts
-            && i < ids.len()
-        {
-            grid.update(i, bounds);
-        }
-    }
-    fn forget_carts(&mut self) {
-        self.carts = None;
-    }
-    /// The slots of the carts whose box may meet `area`, for the cart in slot
-    /// `i` (just moved); false: scan them all.
-    fn carts_near(&mut self, carts: &[Minecart], i: usize, area: Aabb, out: &mut Vec<u32>) -> bool {
-        if !Self::usable() {
-            return false;
-        }
-        let fresh = |ids: &[u32]| ids.len() == carts.len() && ids[i] == carts[i].id;
-        if !self.carts.as_ref().is_some_and(|(_, ids)| fresh(ids)) {
-            self.carts = Some((
-                SeenGrid::new(carts.iter().map(Minecart::bounds)),
-                carts.iter().map(|c| c.id).collect(),
-            ));
-        }
-        let Some((grid, ids)) = &mut self.carts else {
-            return false;
-        };
-        grid.update(i, carts[i].bounds());
-        if !grid.candidates(area, out) {
-            return false;
-        }
-        if out.iter().any(|&j| ids[j as usize] != carts[j as usize].id) {
-            // A cart was replaced in place: start over next time.
-            self.carts = None;
-            return false;
-        }
-        true
-    }
-    /// The slots of the mobs whose box may meet `area` into `out`, and
-    /// whether a mob rides cart `cart`; None: scan them all.
-    fn mobs_near(
-        &mut self,
-        mobs: &JoinList<Mob>,
-        cart: u32,
-        area: Aabb,
-        out: &mut Vec<u32>,
-    ) -> Option<bool> {
-        if !Self::usable() {
-            return None;
-        }
-        if !self
-            .mobs
-            .as_ref()
-            .is_some_and(|(stamp, ..)| *stamp == mobs.stamp())
-        {
-            self.mobs = Some((
-                mobs.stamp(),
-                SeenGrid::new(mobs.iter().map(Mob::bounds)),
-                mobs.iter().filter_map(|m| m.extra.mount).collect(),
-            ));
-        }
-        let (_, grid, mounted) = self.mobs.as_ref()?;
-        grid.candidates(area, out).then(|| mounted.contains(&cart))
-    }
-}
-/// Where the cart `id` is in `carts`: at `hint` (where it was a moment ago,
-/// the usual case while carts tick in order) or found by a scan. A world
-/// with hundreds of mineshaft chest carts asked this of every cart several
-/// times a tick.
-fn cart_at(carts: &[Minecart], id: u32, hint: usize) -> Option<usize> {
-    if carts.get(hint).is_some_and(|c| c.id == id) {
-        return Some(hint);
-    }
-    carts.iter().position(|c| c.id == id)
-}
 /// `AbstractMinecart.push(entity)` for a non-cart `entity` at `feet`:
 /// the push the cart loses (the entity gets a quarter of it back).
 pub(super) fn cart_push_from(feet: Vec3, cart: Vec3) -> Option<(f64, f64)> {
@@ -2984,177 +2892,6 @@ impl Game<'_> {
             .render_state(&scene, state.0, m, light, out);
     }
 }
-/// Saving and loading.
-impl Minecart {
-    pub fn to_nbt(
-        &self,
-        uuid: [i32; 4],
-        raw: Option<&horizon_world::nbt::Tag>,
-    ) -> horizon_world::nbt::Tag {
-        use horizon_world::nbt::{JavaString, Tag};
-        let mut tag = horizon_client::entity_nbt::vehicle_to_nbt(
-            self.kind.id(),
-            self.position,
-            self.velocity,
-            [self.yaw, self.pitch],
-            (self.on_ground, self.fall_distance),
-            uuid,
-            raw,
-        );
-        horizon_client::entity_nbt::write_saved_flags(&mut tag, self.on_ground, self.no_gravity);
-        if let Tag::Compound(map) = &mut tag {
-            // ContainerEntity.addChestVehicleSaveData belongs only to the
-            // container subclasses, never to a plain or specialized cart.
-            if self.kind.slots() == 0 {
-                map.remove(&JavaString::from("Items"));
-            }
-            if self.kind == CartKind::CommandBlock {
-                for key in ["LastOutput", "LastExecution"] {
-                    map.remove(&JavaString::from(key));
-                }
-            }
-            map.remove(&JavaString::from("DisplayOffset"));
-            map.remove(&JavaString::from("DisplayState"));
-            let mut put = |k: &str, v: Tag| {
-                map.insert(JavaString::from(k), v);
-            };
-            put("FlippedRotation", Tag::Byte(i8::from(self.flipped)));
-            // AbstractMinecart saves firstTick as HasTicked. A cart never burns:
-            // Entity.move sets -getFireImmuneTicks(), 0 for all but players.
-            put("HasTicked", Tag::Byte(i8::from(self.first_tick)));
-            put("Fire", Tag::Short(0));
-            // addAdditionalSaveData: the offset only off its default, the state only when set.
-            if let Some(offset) = self.custom_offset
-                && f64::from(offset) != default_display_offset(self.kind)
-            {
-                put("DisplayOffset", Tag::Int(offset));
-            }
-            if let Some(state) = &self.custom_display {
-                put("DisplayState", state.clone());
-            }
-            match self.kind {
-                CartKind::Chest | CartKind::Hopper => {
-                    put("Items", horizon_client::save::encode_items(&self.items));
-                    if self.kind == CartKind::Hopper {
-                        put("Enabled", Tag::Byte(i8::from(self.enabled)));
-                    }
-                }
-                CartKind::Furnace => {
-                    put("PushX", Tag::Double(self.push.x.to_bits()));
-                    put("PushZ", Tag::Double(self.push.z.to_bits()));
-                    put("Fuel", Tag::Short(self.fuel as i16));
-                }
-                CartKind::Tnt => put("fuse", Tag::Int(self.fuse)),
-                // BaseCommandBlock.save (its CustomName shares the entity's key).
-                CartKind::CommandBlock => {
-                    for (key, value) in self.command.save() {
-                        if !matches!(key, "CustomName" | "powered" | "conditionMet" | "auto") {
-                            put(key, value);
-                        }
-                    }
-                }
-                // BaseSpawner.save: the delays, ranges, SpawnData and SpawnPotentials.
-                CartKind::Spawner => {
-                    if let Some(spawner) = &self.spawner {
-                        for (key, value) in
-                            horizon_client::mobs::spawner::SpawnerExt::save(&**spawner)
-                        {
-                            put(key, value);
-                        }
-                    }
-                }
-                CartKind::Rideable => {}
-            }
-            // A loaded loot table goes back while the items are still its roll;
-            // otherwise the items replace it, as vanilla's unpackLootTable does.
-            if self.loot.as_ref().is_some_and(|l| l.restore(map)) {
-                if let Some(table) = horizon_client::save::text(map.get(&"LootTable".into()))
-                    .and_then(|id| horizon_client_core::identifier::normalize_id(&id))
-                {
-                    map.insert("LootTable".into(), Tag::String(table.as_str().into()));
-                }
-            } else {
-                map.remove(&JavaString::from("LootTable"));
-                map.remove(&JavaString::from("LootTableSeed"));
-            }
-        }
-        tag
-    }
-    pub fn from_nbt(tag: &horizon_world::nbt::Tag, id: u32, kind: CartKind) -> Option<Self> {
-        let (position, _, _) = horizon_client::entity_nbt::boat_from_nbt(tag)?;
-        let mut c = Self::new(id, kind, position);
-        c.load(tag)?;
-        Some(c)
-    }
-    /// `Entity.load` on this cart: the saved fields are read over the live
-    /// ones, the rest (riders, lerp, hurt state) stays; its kind never changes.
-    /// `None`, with nothing changed, when the compound has no position.
-    pub fn load(&mut self, tag: &horizon_world::nbt::Tag) -> Option<()> {
-        use horizon_world::nbt::Tag;
-        let (position, velocity, yaw) = horizon_client::entity_nbt::boat_from_nbt(tag)?;
-        let kind = self.kind;
-        let c = self;
-        c.position = position;
-        c.previous = position;
-        c.velocity = velocity;
-        c.yaw = yaw;
-        c.previous_yaw = yaw;
-        c.no_gravity = horizon_client::entity_nbt::flag(tag, "NoGravity");
-        c.on_ground = horizon_client::entity_nbt::flag(tag, "OnGround");
-        c.pitch = horizon_client::entity_nbt::rotation(tag)[1];
-        c.previous_pitch = c.pitch;
-        // ValueInput's numeric getters take any NumericTag: getIntOr is its
-        // intValue, getShortOr the low 16 bits of it, getBooleanOr
-        // `byteValue() != 0` (the low 8), getDoubleOr its doubleValue.
-        let int = |k: &str| {
-            tag.get(k)
-                .and_then(horizon_client_core::nbt_path::int_value)
-        };
-        let flag = |k: &str, default: bool| int(k).map_or(default, |v| v as i8 != 0);
-        let double = |k: &str| match tag.get(k) {
-            Some(Tag::Byte(v)) => f64::from(*v),
-            Some(Tag::Short(v)) => f64::from(*v),
-            Some(Tag::Int(v)) => f64::from(*v),
-            Some(Tag::Long(v)) => *v as f64,
-            Some(Tag::Float(v)) => f64::from(f32::from_bits(*v)),
-            Some(Tag::Double(v)) => f64::from_bits(*v),
-            _ => 0.0,
-        };
-        // Entity.load: OnGround and fall_distance, as saved.
-        (c.on_ground, c.fall_distance) = horizon_client::entity_nbt::ground_from_nbt(tag);
-        c.flipped = flag("FlippedRotation", false);
-        c.first_tick = flag("HasTicked", false);
-        if kind.slots() > 0 {
-            c.items = horizon_client::save::decode_items(tag.get("Items"), kind.slots());
-        }
-        c.enabled = flag("Enabled", true);
-        c.fuel = int("Fuel").map_or(0, |v| i32::from(v as i16));
-        // readAdditionalSaveData: the saved push has no y.
-        c.push = Vec3::new(double("PushX"), 0.0, double("PushZ"));
-        c.fuse = int("fuse").unwrap_or(-1);
-        // readAdditionalSaveData: DisplayState, DisplayOffset (default offset when absent).
-        c.custom_display = tag.get("DisplayState").cloned();
-        c.custom_offset = int("DisplayOffset");
-        if kind == CartKind::CommandBlock {
-            c.command = horizon_client::command_block::CommandBlock::load(tag);
-            // MinecartCommandBlock.readAdditionalSaveData sets the synched command.
-            // A changed value invokes onSyncedDataUpdated -> setCommand, resetting successes.
-            if c.synced_command != c.command.command {
-                c.synced_command.clone_from(&c.command.command);
-                c.command.set_command(&c.synced_command);
-            }
-            c.synced_output = c.command.last_output_string();
-        }
-        // MinecartSpawner.readAdditionalSaveData: BaseSpawner.load.
-        if kind == CartKind::Spawner {
-            c.spawner = Some(Box::new(horizon_client::mobs::spawner::SpawnerExt::load(
-                tag,
-            )));
-        }
-        Some(())
-    }
-}
-
 /// `VehicleEntity.hurtServer`'s destroy test: a creative player, damage past
 /// 40, or (`MinecartTNT.shouldSourceDestroy`) fire or an explosion hitting a
 /// TNT cart.

crates/horizon-client/src/game/minecarts/index.rs

@@ -0,0 +1,105 @@
+//! The carts' and mobs' boxes for a tick's cart pushes ([`CartIndex`]).
+use super::*;
+
+/// The carts' and mobs' boxes for one tick's cart pushes (`push_from_cart`,
+/// `pickup_from_cart`), so a cart reads its neighbours instead of every cart and
+/// every mob of the level. Both answer in slot order, as the scans did.
+///
+/// The cart grid follows each ticked cart ([`CartIndex::moved`]); it is
+/// rebuilt once the list's length changed (a cart gone or added), and dropped
+/// after a command, which can move or replace any cart
+/// ([`CartIndex::forget_carts`]). The mob grid holds until the mob
+/// list's next write ([`ListStamp`]). A native mod's hook can move either kind
+/// unseen, so with mods loaded both scans stay.
+#[derive(Default)]
+pub(in crate::game) struct CartIndex {
+    pub(super) carts: Option<(SeenGrid, Vec<u32>)>,
+    /// The grid, and the carts a mob rides.
+    pub(super) mobs: Option<(ListStamp, SeenGrid, FxHashSet<u32>)>,
+    pub(super) near: Vec<u32>,
+}
+impl CartIndex {
+    pub(super) fn usable() -> bool {
+        horizon_client::mod_api::mods().is_empty()
+    }
+    /// The cart in slot `i` has these bounds now.
+    pub(super) fn moved(&mut self, i: usize, bounds: Aabb) {
+        if let Some((grid, ids)) = &mut self.carts
+            && i < ids.len()
+        {
+            grid.update(i, bounds);
+        }
+    }
+    pub(super) fn forget_carts(&mut self) {
+        self.carts = None;
+    }
+    /// The slots of the carts whose box may meet `area`, for the cart in slot
+    /// `i` (just moved); false: scan them all.
+    pub(super) fn carts_near(
+        &mut self,
+        carts: &[Minecart],
+        i: usize,
+        area: Aabb,
+        out: &mut Vec<u32>,
+    ) -> bool {
+        if !Self::usable() {
+            return false;
+        }
+        let fresh = |ids: &[u32]| ids.len() == carts.len() && ids[i] == carts[i].id;
+        if !self.carts.as_ref().is_some_and(|(_, ids)| fresh(ids)) {
+            self.carts = Some((
+                SeenGrid::new(carts.iter().map(Minecart::bounds)),
+                carts.iter().map(|c| c.id).collect(),
+            ));
+        }
+        let Some((grid, ids)) = &mut self.carts else {
+            return false;
+        };
+        grid.update(i, carts[i].bounds());
+        if !grid.candidates(area, out) {
+            return false;
+        }
+        if out.iter().any(|&j| ids[j as usize] != carts[j as usize].id) {
+            // A cart was replaced in place: start over next time.
+            self.carts = None;
+            return false;
+        }
+        true
+    }
+    /// The slots of the mobs whose box may meet `area` into `out`, and
+    /// whether a mob rides cart `cart`; None: scan them all.
+    pub(super) fn mobs_near(
+        &mut self,
+        mobs: &JoinList<Mob>,
+        cart: u32,
+        area: Aabb,
+        out: &mut Vec<u32>,
+    ) -> Option<bool> {
+        if !Self::usable() {
+            return None;
+        }
+        if !self
+            .mobs
+            .as_ref()
+            .is_some_and(|(stamp, ..)| *stamp == mobs.stamp())
+        {
+            self.mobs = Some((
+                mobs.stamp(),
+                SeenGrid::new(mobs.iter().map(Mob::bounds)),
+                mobs.iter().filter_map(|m| m.extra.mount).collect(),
+            ));
+        }
+        let (_, grid, mounted) = self.mobs.as_ref()?;
+        grid.candidates(area, out).then(|| mounted.contains(&cart))
+    }
+}
+/// Where the cart `id` is in `carts`: at `hint` (where it was a moment ago,
+/// the usual case while carts tick in order) or found by a scan. A world
+/// with hundreds of mineshaft chest carts asked this of every cart several
+/// times a tick.
+pub(super) fn cart_at(carts: &[Minecart], id: u32, hint: usize) -> Option<usize> {
+    if carts.get(hint).is_some_and(|c| c.id == id) {
+        return Some(hint);
+    }
+    carts.iter().position(|c| c.id == id)
+}

crates/horizon-client/src/game/minecarts/nbt.rs

@@ -0,0 +1,173 @@
+//! Saving and loading a minecart.
+use super::*;
+
+/// Saving and loading.
+impl Minecart {
+    pub fn to_nbt(
+        &self,
+        uuid: [i32; 4],
+        raw: Option<&horizon_world::nbt::Tag>,
+    ) -> horizon_world::nbt::Tag {
+        use horizon_world::nbt::{JavaString, Tag};
+        let mut tag = horizon_client::entity_nbt::vehicle_to_nbt(
+            self.kind.id(),
+            self.position,
+            self.velocity,
+            [self.yaw, self.pitch],
+            (self.on_ground, self.fall_distance),
+            uuid,
+            raw,
+        );
+        horizon_client::entity_nbt::write_saved_flags(&mut tag, self.on_ground, self.no_gravity);
+        if let Tag::Compound(map) = &mut tag {
+            // ContainerEntity.addChestVehicleSaveData belongs only to the
+            // container subclasses, never to a plain or specialized cart.
+            if self.kind.slots() == 0 {
+                map.remove(&JavaString::from("Items"));
+            }
+            if self.kind == CartKind::CommandBlock {
+                for key in ["LastOutput", "LastExecution"] {
+                    map.remove(&JavaString::from(key));
+                }
+            }
+            map.remove(&JavaString::from("DisplayOffset"));
+            map.remove(&JavaString::from("DisplayState"));
+            let mut put = |k: &str, v: Tag| {
+                map.insert(JavaString::from(k), v);
+            };
+            put("FlippedRotation", Tag::Byte(i8::from(self.flipped)));
+            // AbstractMinecart saves firstTick as HasTicked. A cart never burns:
+            // Entity.move sets -getFireImmuneTicks(), 0 for all but players.
+            put("HasTicked", Tag::Byte(i8::from(self.first_tick)));
+            put("Fire", Tag::Short(0));
+            // addAdditionalSaveData: the offset only off its default, the state only when set.
+            if let Some(offset) = self.custom_offset
+                && f64::from(offset) != default_display_offset(self.kind)
+            {
+                put("DisplayOffset", Tag::Int(offset));
+            }
+            if let Some(state) = &self.custom_display {
+                put("DisplayState", state.clone());
+            }
+            match self.kind {
+                CartKind::Chest | CartKind::Hopper => {
+                    put("Items", horizon_client::save::encode_items(&self.items));
+                    if self.kind == CartKind::Hopper {
+                        put("Enabled", Tag::Byte(i8::from(self.enabled)));
+                    }
+                }
+                CartKind::Furnace => {
+                    put("PushX", Tag::Double(self.push.x.to_bits()));
+                    put("PushZ", Tag::Double(self.push.z.to_bits()));
+                    put("Fuel", Tag::Short(self.fuel as i16));
+                }
+                CartKind::Tnt => put("fuse", Tag::Int(self.fuse)),
+                // BaseCommandBlock.save (its CustomName shares the entity's key).
+                CartKind::CommandBlock => {
+                    for (key, value) in self.command.save() {
+                        if !matches!(key, "CustomName" | "powered" | "conditionMet" | "auto") {
+                            put(key, value);
+                        }
+                    }
+                }
+                // BaseSpawner.save: the delays, ranges, SpawnData and SpawnPotentials.
+                CartKind::Spawner => {
+                    if let Some(spawner) = &self.spawner {
+                        for (key, value) in
+                            horizon_client::mobs::spawner::SpawnerExt::save(&**spawner)
+                        {
+                            put(key, value);
+                        }
+                    }
+                }
+                CartKind::Rideable => {}
+            }
+            // A loaded loot table goes back while the items are still its roll;
+            // otherwise the items replace it, as vanilla's unpackLootTable does.
+            if self.loot.as_ref().is_some_and(|l| l.restore(map)) {
+                if let Some(table) = horizon_client::save::text(map.get(&"LootTable".into()))
+                    .and_then(|id| horizon_client_core::identifier::normalize_id(&id))
+                {
+                    map.insert("LootTable".into(), Tag::String(table.as_str().into()));
+                }
+            } else {
+                map.remove(&JavaString::from("LootTable"));
+                map.remove(&JavaString::from("LootTableSeed"));
+            }
+        }
+        tag
+    }
+    pub fn from_nbt(tag: &horizon_world::nbt::Tag, id: u32, kind: CartKind) -> Option<Self> {
+        let (position, _, _) = horizon_client::entity_nbt::boat_from_nbt(tag)?;
+        let mut c = Self::new(id, kind, position);
+        c.load(tag)?;
+        Some(c)
+    }
+    /// `Entity.load` on this cart: the saved fields are read over the live
+    /// ones, the rest (riders, lerp, hurt state) stays; its kind never changes.
+    /// `None`, with nothing changed, when the compound has no position.
+    pub fn load(&mut self, tag: &horizon_world::nbt::Tag) -> Option<()> {
+        use horizon_world::nbt::Tag;
+        let (position, velocity, yaw) = horizon_client::entity_nbt::boat_from_nbt(tag)?;
+        let kind = self.kind;
+        let c = self;
+        c.position = position;
+        c.previous = position;
+        c.velocity = velocity;
+        c.yaw = yaw;
+        c.previous_yaw = yaw;
+        c.no_gravity = horizon_client::entity_nbt::flag(tag, "NoGravity");
+        c.on_ground = horizon_client::entity_nbt::flag(tag, "OnGround");
+        c.pitch = horizon_client::entity_nbt::rotation(tag)[1];
+        c.previous_pitch = c.pitch;
+        // ValueInput's numeric getters take any NumericTag: getIntOr is its
+        // intValue, getShortOr the low 16 bits of it, getBooleanOr
+        // `byteValue() != 0` (the low 8), getDoubleOr its doubleValue.
+        let int = |k: &str| {
+            tag.get(k)
+                .and_then(horizon_client_core::nbt_path::int_value)
+        };
+        let flag = |k: &str, default: bool| int(k).map_or(default, |v| v as i8 != 0);
+        let double = |k: &str| match tag.get(k) {
+            Some(Tag::Byte(v)) => f64::from(*v),
+            Some(Tag::Short(v)) => f64::from(*v),
+            Some(Tag::Int(v)) => f64::from(*v),
+            Some(Tag::Long(v)) => *v as f64,
+            Some(Tag::Float(v)) => f64::from(f32::from_bits(*v)),
+            Some(Tag::Double(v)) => f64::from_bits(*v),
+            _ => 0.0,
+        };
+        // Entity.load: OnGround and fall_distance, as saved.
+        (c.on_ground, c.fall_distance) = horizon_client::entity_nbt::ground_from_nbt(tag);
+        c.flipped = flag("FlippedRotation", false);
+        c.first_tick = flag("HasTicked", false);
+        if kind.slots() > 0 {
+            c.items = horizon_client::save::decode_items(tag.get("Items"), kind.slots());
+        }
+        c.enabled = flag("Enabled", true);
+        c.fuel = int("Fuel").map_or(0, |v| i32::from(v as i16));
+        // readAdditionalSaveData: the saved push has no y.
+        c.push = Vec3::new(double("PushX"), 0.0, double("PushZ"));
+        c.fuse = int("fuse").unwrap_or(-1);
+        // readAdditionalSaveData: DisplayState, DisplayOffset (default offset when absent).
+        c.custom_display = tag.get("DisplayState").cloned();
+        c.custom_offset = int("DisplayOffset");
+        if kind == CartKind::CommandBlock {
+            c.command = horizon_client::command_block::CommandBlock::load(tag);
+            // MinecartCommandBlock.readAdditionalSaveData sets the synched command.
+            // A changed value invokes onSyncedDataUpdated -> setCommand, resetting successes.
+            if c.synced_command != c.command.command {
+                c.synced_command.clone_from(&c.command.command);
+                c.command.set_command(&c.synced_command);
+            }
+            c.synced_output = c.command.last_output_string();
+        }
+        // MinecartSpawner.readAdditionalSaveData: BaseSpawner.load.
+        if kind == CartKind::Spawner {
+            c.spawner = Some(Box::new(horizon_client::mobs::spawner::SpawnerExt::load(
+                tag,
+            )));
+        }
+        Some(())
+    }
+}

crates/horizon-client/src/game/remote.rs

@@ -11496,8 +11496,7 @@ impl Remote {
     pub(super) fn listed_player_count(&self) -> usize {
         self.listed.len()
     }
-    /// Players in the server's player list, this one included (for Discord).
-    #[cfg(feature = "discord")]
+    /// Players in the server's player list, this one included (for the activity hooks).
     pub(super) fn player_count(&self) -> usize {
         self.players.len()
     }

crates/horizon-client/src/game/resource_loader.rs

@@ -306,8 +306,6 @@ pub(super) fn run_loading(
         App::Loading(loading) => leave_fullscreen_after(&result, &mut loading.settings),
     }
     result?;
-    #[cfg(feature = "discord")]
-    horizon_client::discord_presence::stop();
     match app {
         App::Ready(mut split) => {
             write_report(&split.host)?;

crates/horizon-discord/Cargo.toml

@@ -0,0 +1,15 @@
+[package]
+name = "horizon-discord"
+version = "0.1.0"
+edition.workspace = true
+license.workspace = true
+rust-version.workspace = true
+description = "Discord Rich Presence: \"Playing Horizon\" on the player's Discord profile (docs/native-client.md)"
+
+[dependencies]
+horizon-platform = { path = "../horizon-platform" }
+log = "0.4"
+serde_json = "1.0.151"
+
+[lints]
+workspace = true

crates/horizon-discord/src/lib.rs

@@ -1,21 +1,30 @@
 //! Discord Rich Presence: "Playing Horizon" on the player's Discord profile, with what they are
 //! doing (docs/native-client.md). A thread of its own talks to the Discord app on this computer
 //! through its local IPC socket (Discord's RPC docs: `discord-ipc-N`, frames of opcode u32 LE +
-//! length u32 LE + JSON). The game only calls [`set`] each frame: a change wakes the thread,
+//! length u32 LE + JSON). The game says what the player does on each change ([`set`]), which wakes the thread,
 //! which connects when Discord runs, retries every 15 s when it doesn't, keeps under Discord's
 //! update limit and clears the activity on quit. Nothing is sent with the setting off,
-//! or with `HORIZON_NO_DISCORD=1`. It uses nothing else of the game (docs/layers.md: Horizon layer):
-//! `game/discord.rs` says what the player does.
+//! or with `HORIZON_NO_DISCORD=1`.
+//!
+//! A Horizon crate (docs/layers.md): the game tells it what the player does through the
+//! platform's hooks ([`HOOKS`]: `client_started`, `activity`, `shutdown`), which the official
+//! executable (`horizon-official`) registers with the switch: its line of `horizon-extras.txt`
+//! ([`SETTING`]) and its row in Extras' Multiplayer group ([`SECTION`]). horizon-client's own
+//! executable has no presence.
+#![forbid(unsafe_code)]
 use std::collections::VecDeque;
 use std::io::{self, Read, Write};
 use std::path::PathBuf;
+use std::sync::atomic::{AtomicBool, Ordering};
 use std::sync::{Condvar, Mutex, OnceLock};
 use std::thread::Thread;
 use std::time::{Duration, Instant, SystemTime, UNIX_EPOCH};
 
 use serde_json::{Value, json};
 
-use horizon_command::args::GameMode;
+use horizon_platform::hooks::{self, Activity, Dimension, GameMode, Hooks, Play};
+use horizon_platform::pages::{Act, Label, Page, Place, Row};
+use horizon_platform::settings::Store;
 
 /// The "Horizon" application on Discord's developer portal (public: it names the game). Its
 /// Rich Presence assets: `horizon`, the logo.
@@ -40,24 +49,134 @@ const CLOSE: u32 = 2;
 const PING: u32 = 3;
 const PONG: u32 = 4;
 
-#[derive(Clone, Copy, Debug, PartialEq, Eq)]
-pub enum Dimension {
-    Overworld,
-    Nether,
-    End,
+/// The presence's hooks, for `horizon_platform::hooks::register`.
+pub static HOOKS: Presence = Presence;
+
+pub struct Presence;
+
+impl Hooks for Presence {
+    /// Starts the presence thread with the game's window (never for a dedicated server).
+    fn client_started(&self, client: &hooks::Client) {
+        start(client.automated);
+    }
+
+    fn activity(&self, now: Activity) {
+        set(match now {
+            Activity::Menus => Status::Menus,
+            Activity::World {
+                play,
+                dimension,
+                mode,
+            } => Status::World {
+                play,
+                dimension,
+                mode,
+            },
+            // Anything a later game says that this crate doesn't know yet.
+            _ => Status::Off,
+        });
+    }
+
+    /// On quit: the activity is cleared.
+    fn shutdown(&self) {
+        stop();
+    }
 }
 
-#[derive(Clone, Copy, Debug, PartialEq, Eq)]
-pub enum Play {
-    Singleplayer,
-    /// A server or someone else's LAN world. Its address and name are never shown.
-    Multiplayer,
-    /// This world is open to LAN or friends; `players` counts the host, `max` is how many
-    /// may join.
-    Hosting {
-        players: usize,
-        max: usize,
-    },
+/// The switch's line in `horizon-extras.txt`, where the engine's Extras kept it before.
+const KEY: &str = "discordPresence";
+/// The switch's row, and what it says on hover.
+const LABEL: &str = "horizon.extras.discord_presence";
+const ABOUT: &str = "horizon.extras.discord_presence.tooltip";
+
+/// The switch (on by default): the player's own settings' line, the game's first player's. A
+/// splitscreen player's settings file loads after the first player's and keeps it.
+static ON: AtomicBool = AtomicBool::new(true);
+/// Whether the player's settings were loaded once: the later loads are splitscreen players'.
+static LOADED: AtomicBool = AtomicBool::new(false);
+
+/// Turns the presence on or off; off clears the activity at once.
+pub fn set_enabled(on: bool) {
+    ON.store(on, Ordering::Relaxed);
+    let mut shared = lock();
+    let status = shown(shared.game);
+    let changed = shared.wanted.update(status, unix_now());
+    drop(shared);
+    if let Some(thread) = THREAD.get().filter(|_| changed) {
+        thread.unpark();
+    }
+}
+
+pub fn enabled() -> bool {
+    ON.load(Ordering::Relaxed)
+}
+
+/// What Discord is told for the game's `status`: nothing with the switch off.
+fn shown(status: Status) -> Status {
+    if enabled() { status } else { Status::Off }
+}
+
+/// The switch's line of `horizon-extras.txt`, for `horizon_platform::settings::register`.
+pub static SETTING: Setting = Setting;
+
+pub struct Setting;
+
+impl Store for Setting {
+    fn file(&self) -> &'static str {
+        "horizon-extras.txt"
+    }
+    fn owns(&self, key: &str) -> bool {
+        key == KEY
+    }
+    fn load(&self, _key: &str, value: &str) {
+        // The first player's settings load first; the first load is theirs.
+        if LOADED.swap(true, Ordering::Relaxed) {
+            return;
+        }
+        match value {
+            "true" => set_enabled(true),
+            "false" => set_enabled(false),
+            _ => {}
+        }
+    }
+    fn save(&self, line: &mut dyn FnMut(&str, &str)) {
+        line(KEY, if enabled() { "true" } else { "false" });
+    }
+    fn is_default(&self) -> bool {
+        enabled()
+    }
+}
+
+/// The switch's row in the Extras page's Multiplayer group, for
+/// `horizon_platform::pages::register`.
+pub static SECTION: Section = Section;
+
+pub struct Section;
+
+impl Page for Section {
+    fn id(&self) -> &'static str {
+        "horizon-discord.extras"
+    }
+    fn title(&self) -> &'static str {
+        "horizon.extras.header.multiplayer"
+    }
+    fn place(&self) -> Place {
+        Place::Extras
+    }
+    fn rows(&self, rows: &mut Vec<Row>) {
+        rows.push(Row::Toggle {
+            label: LABEL,
+            on: enabled(),
+        });
+    }
+    fn act(&self, row: usize, act: Act) {
+        if row == 0 && matches!(act, Act::Press | Act::PressBack) {
+            set_enabled(!enabled());
+        }
+    }
+    fn tooltip(&self, _row: usize) -> Option<Label> {
+        Some(Label::Key(ABOUT))
+    }
 }
 
 #[derive(Clone, Copy, Debug, PartialEq, Eq)]
@@ -97,11 +216,15 @@ impl Wanted {
 }
 
 struct Shared {
+    /// What the game said last.
+    game: Status,
+    /// What Discord is to show: the game's, or nothing with the switch off.
     wanted: Wanted,
     stop: bool,
     stopped: bool,
 }
 static SHARED: Mutex<Shared> = Mutex::new(Shared {
+    game: Status::Menus,
     wanted: Wanted {
         status: Status::Menus,
         since: None,
@@ -114,7 +237,8 @@ static THREAD: OnceLock<Thread> = OnceLock::new();
 
 /// Starts the presence thread, once: when the game starts, never for a dedicated server.
 /// `automated` runs (offscreen, benchmarks) only talk to a test's fake Discord.
-pub fn start(enabled: bool, automated: bool) {
+/// The status [`set`] gave before, the switch included, is the first one sent.
+pub fn start(automated: bool) {
     let fake_discord = std::env::var_os(IPC_DIR_ENV).is_some();
     if THREAD.get().is_some()
         || std::env::var_os("HORIZON_NO_DISCORD").is_some_and(|v| v != "0")
@@ -122,9 +246,6 @@ pub fn start(enabled: bool, automated: bool) {
     {
         return;
     }
-    if !enabled {
-        lock().wanted.status = Status::Off;
-    }
     match std::thread::Builder::new()
         .name("Discord presence".into())
         .spawn(run)
@@ -136,12 +257,13 @@ pub fn start(enabled: bool, automated: bool) {
     }
 }
 
-/// What the player does now; only a change wakes the thread. Free without [`start`].
+/// What the player does now; only a change wakes the thread. Kept for [`start`] before it.
 pub fn set(status: Status) {
-    let Some(thread) = THREAD.get() else {
-        return;
-    };
-    if lock().wanted.update(status, unix_now()) {
+    let mut shared = lock();
+    shared.game = status;
+    let changed = shared.wanted.update(shown(status), unix_now());
+    drop(shared);
+    if let Some(thread) = THREAD.get().filter(|_| changed) {
         thread.unpark();
     }
 }
@@ -582,6 +704,39 @@ mod tests {
 
     /// A fake Discord: answers the handshake with READY, each command with its nonce, after a ping.
     #[cfg(unix)]
+    /// The switch as the player's settings and the Extras page see it. The only test that
+    /// touches the presence's statics.
+    #[test]
+    fn the_switch_clears_the_activity_and_keeps_the_first_players_line() {
+        let wanted = || lock().wanted.status;
+        Setting.load(KEY, "false");
+        // A splitscreen player's settings file loads later and keeps the first player's.
+        Setting.load(KEY, "true");
+        set(Status::Menus);
+        assert!(!enabled());
+        assert_eq!(wanted(), Status::Off);
+        let mut rows = Vec::new();
+        SECTION.rows(&mut rows);
+        assert_eq!(
+            rows,
+            [Row::Toggle {
+                label: LABEL,
+                on: false
+            }]
+        );
+        let mut lines = Vec::new();
+        Setting.save(&mut |k, v| lines.push(format!("{k}:{v}")));
+        assert_eq!(lines, ["discordPresence:false"]);
+        assert!(!Setting.is_default());
+        // On from the page: what the game said last is shown at once.
+        SECTION.act(0, Act::Press);
+        assert_eq!(wanted(), Status::Menus);
+        assert!(Setting.is_default());
+        SECTION.act(0, Act::Press);
+        assert_eq!(wanted(), Status::Off);
+        SECTION.act(0, Act::Press);
+    }
+
     #[test]
     fn talks_to_discord_over_its_socket() {
         let dir = std::env::temp_dir().join(format!("horizon-discord-{}", std::process::id()));

crates/horizon-hooks/src/lib.rs

@@ -48,6 +48,69 @@ pub trait Hooks: Sync {
     fn tunnel(&self) -> Option<&dyn tunnel::Resolver> {
         None
     }
+
+    /// A game window opened: once, before the first frame, for every run that has a window,
+    /// automated ones included ([`Client::automated`]); never for a dedicated server.
+    fn client_started(&self, _client: &Client) {}
+
+    /// What the player is doing, for a status shown outside the game (Discord's): called when it
+    /// changes, not every frame. Splitscreen: the first player's only.
+    fn activity(&self, _now: Activity) {}
+}
+
+/// What [`Hooks::client_started`] gets.
+#[non_exhaustive]
+pub struct Client {
+    /// A run nobody plays: offscreen, a benchmark, a run that quits by itself after some frames.
+    pub automated: bool,
+}
+
+impl Client {
+    pub fn new(automated: bool) -> Self {
+        Self { automated }
+    }
+}
+
+/// What the player is doing ([`Hooks::activity`]).
+#[derive(Clone, Copy, Debug, PartialEq, Eq)]
+#[non_exhaustive]
+pub enum Activity {
+    /// On the title screen or another menu outside a world.
+    Menus,
+    World {
+        play: Play,
+        dimension: Dimension,
+        mode: GameMode,
+    },
+}
+
+/// How the player is in a world.
+#[derive(Clone, Copy, Debug, PartialEq, Eq)]
+pub enum Play {
+    Singleplayer,
+    /// A server or someone else's LAN world.
+    Multiplayer,
+    /// Their world is open to LAN or friends; `players` counts the host, `max` is how many may
+    /// join.
+    Hosting {
+        players: usize,
+        max: usize,
+    },
+}
+
+#[derive(Clone, Copy, Debug, PartialEq, Eq)]
+pub enum Dimension {
+    Overworld,
+    Nether,
+    End,
+}
+
+#[derive(Clone, Copy, Debug, PartialEq, Eq)]
+pub enum GameMode {
+    Survival,
+    Creative,
+    Adventure,
+    Spectator,
 }
 
 /// What [`Hooks::started`] gets.
@@ -55,11 +118,14 @@ pub trait Hooks: Sync {
 pub struct Started<'a> {
     /// The build: the release tag (`0.2.31`), or `dev <crate version>` for a build from source.
     pub version: &'a str,
+    /// The player's game folder: servers.dat, options.txt and saves (the working directory unless
+    /// `--game-dir` names another).
+    pub game_dir: &'a std::path::Path,
 }
 
 impl<'a> Started<'a> {
-    pub fn new(version: &'a str) -> Self {
-        Self { version }
+    pub fn new(version: &'a str, game_dir: &'a std::path::Path) -> Self {
+        Self { version, game_dir }
     }
 }
 
@@ -123,6 +189,32 @@ pub mod engine {
         }
     }
 
+    /// [`Hooks::client_started`].
+    pub fn client_started(client: &Client) {
+        for hooks in all() {
+            hooks.client_started(client);
+        }
+    }
+
+    /// The activity at the last call (`None` before the first).
+    static ACTIVITY: std::sync::Mutex<Option<Activity>> = std::sync::Mutex::new(None);
+
+    /// [`Hooks::activity`], when `now` differs from the last call's. Cheap enough to call every
+    /// frame: with no hook registered it only loads the empty list.
+    pub fn activity(now: Activity) {
+        let hooks = all();
+        if hooks.is_empty() {
+            return;
+        }
+        let mut last = ACTIVITY.lock().unwrap_or_else(|e| e.into_inner());
+        if last.replace(now) != Some(now) {
+            drop(last);
+            for h in hooks {
+                h.activity(now);
+            }
+        }
+    }
+
     /// [`Hooks::shutdown`].
     pub fn shutdown() {
         for hooks in all() {
@@ -155,6 +247,9 @@ mod tests {
         fn published(&self, open: bool) {
             self.0.lock().unwrap().push(format!("published {open}"));
         }
+        fn activity(&self, now: Activity) {
+            self.0.lock().unwrap().push(format!("{now:?}"));
+        }
     }
 
     /// Implements nothing: the defaults do nothing.
@@ -167,15 +262,29 @@ mod tests {
     fn registered_hooks_hear_the_game_and_late_ones_are_refused() {
         register(&RECORDER).unwrap();
         register(&Silent).unwrap();
-        engine::started(&Started::new("0.2.31"));
+        engine::started(&Started::new("0.2.31", std::path::Path::new("game")));
         // Changes only: the same state every frame is said once.
         for open in [false, true, true, true, false, false] {
             engine::published(open);
         }
+        let world = Activity::World {
+            play: Play::Singleplayer,
+            dimension: Dimension::Nether,
+            mode: GameMode::Creative,
+        };
+        for now in [Activity::Menus, Activity::Menus, world, world] {
+            engine::activity(now);
+        }
         engine::shutdown();
         assert_eq!(
             *RECORDER.0.lock().unwrap(),
-            ["started 0.2.31", "published true", "published false"]
+            [
+                "started 0.2.31",
+                "published true",
+                "published false",
+                "Menus",
+                "World { play: Singleplayer, dimension: Nether, mode: Creative }"
+            ]
         );
         assert_eq!(register(&Silent), Err(TooLate));
     }

crates/horizon-official-servers/Cargo.toml

@@ -0,0 +1,15 @@
+[package]
+name = "horizon-official-servers"
+version = "0.1.0"
+edition.workspace = true
+license.workspace = true
+rust-version.workspace = true
+description = "Horizon's official server in the multiplayer list, and the withdrawn partner server taken out of it (docs/layers.md)"
+
+[dependencies]
+horizon-addresses = { path = "../horizon-addresses" }
+horizon-platform = { path = "../horizon-platform", features = ["protocol"] }
+log = "0.4"
+
+[lints]
+workspace = true

crates/horizon-official-servers/src/lib.rs

@@ -1,12 +1,29 @@
-//! Horizon's own entries in the multiplayer list (docs/layers.md: Horizon layer): the official
-//! server, added once at the top, and the withdrawn partner server, taken back out once. Behind
-//! `horizon-extras` (docs/forking.md), so a plain build adds no server and holds no Horizon
-//! address. It reads and writes servers.dat only through `horizon_protocol::servers`, ready to
-//! leave the engine crates for a Horizon crate.
-use horizon_protocol::servers::{self, ServerEntry};
+//! Horizon's own entries in the multiplayer list: the official server, added once at the top,
+//! and the withdrawn partner server, taken back out once.
+//!
+//! A Horizon crate (docs/layers.md): it plugs into the game through the platform's hooks
+//! ([`HOOKS`], when the game starts), which the official executable (`horizon-official`)
+//! registers, and reads servers.dat through `horizon_platform::servers`. horizon-client's plain
+//! executable adds no server. Its addresses are in `horizon-addresses`.
+#![forbid(unsafe_code)]
+
+use horizon_platform::hooks::{Hooks, Started};
+use horizon_platform::servers::{self, ServerEntry};
 use std::path::Path;
 
-/// At startup of a player's game: the official server into the list in `game_dir` and the
+/// The server list's hooks, for `horizon_platform::hooks::register`.
+pub static HOOKS: OfficialServers = OfficialServers;
+
+pub struct OfficialServers;
+
+impl Hooks for OfficialServers {
+    /// Someone is playing (not a server, a benchmark or an automated run): their list, once.
+    fn started(&self, game: &Started<'_>) {
+        update(game.game_dir);
+    }
+}
+
+/// At the start of a player's game: the official server into the list in `game_dir` and the
 /// withdrawn partner server out of it, a failure only logged.
 pub fn update(game_dir: &Path) {
     if let Err(e) = add_official_server(game_dir) {
@@ -17,12 +34,8 @@ pub fn update(game_dir: &Path) {
     }
 }
 
-/// Horizon's official survival server: a name and an address like any entry. The address is
-/// `horizon_telemetry::server_status::OFFICIAL_ADDRESS`, the one place it is kept.
-pub const OFFICIAL_SERVER: (&str, &str) = (
-    "Horizon Official",
-    horizon_telemetry::server_status::OFFICIAL_ADDRESS,
-);
+/// Horizon's official survival server: a name and an address like any entry.
+pub const OFFICIAL_SERVER: (&str, &str) = ("Horizon Official", horizon_addresses::OFFICIAL_SERVER);
 /// Beside servers.dat once the official server was offered, so a player who
 /// deletes it never gets it back: the address offered, so a new one moves the
 /// list once. The launcher writes the same file.
@@ -55,7 +68,7 @@ pub fn add_official_server(game_dir: &Path) -> std::io::Result<()> {
     let file = game_dir.join("servers.dat");
     let _guard = servers::lock();
     let mut list = servers::load(&file);
-    let previous = horizon_telemetry::server_status::OFFICIAL_PREVIOUS;
+    let previous = horizon_addresses::OFFICIAL_SERVER_PREVIOUS;
     if move_official(&mut list, address, previous) {
         servers::save(&file, &list)?;
     }
@@ -71,7 +84,10 @@ pub fn add_official_server(game_dir: &Path) -> std::io::Result<()> {
 
 /// Afri-Network, which the game added once below the official server (#9299) until the
 /// partnership ended: the name and address the game gave its entry.
-const WITHDRAWN_PARTNER: (&str, &str) = ("Afri-Network (South Africa)", "afri-network.co.za");
+const WITHDRAWN_PARTNER: (&str, &str) = (
+    "Afri-Network (South Africa)",
+    horizon_addresses::WITHDRAWN_PARTNER_SERVER,
+);
 /// Beside servers.dat: the partner addresses the game offered, one per line (#9299).
 const PARTNER_MARKER: &str = "horizon_partner_servers.txt";
 

crates/horizon-official/Cargo.toml

@@ -15,6 +15,8 @@ horizon-game = { path = "../horizon-game" }
 horizon-platform = { path = "../horizon-platform" }
 horizon-heartbeat = { path = "../horizon-heartbeat" }
 horizon-friends = { path = "../horizon-friends", features = ["game"] }
+horizon-official-servers = { path = "../horizon-official-servers" }
+horizon-discord = { path = "../horizon-discord" }
 log = "0.4"
 
 [build-dependencies]

crates/horizon-official/src/lib.rs

@@ -4,25 +4,36 @@
 //! (`game-build.yml`); horizon-client keeps its own plain executable.
 //!
 //! Each Horizon crate that runs in the game gives a `&'static` value implementing
-//! `horizon_platform::hooks::Hooks`, and [`register`] adds it. Nothing here depends on an engine
-//! crate.
+//! `horizon_platform::hooks::Hooks`, and its settings store and pages if it has any, and
+//! [`register`] adds them. Nothing here depends on an engine crate.
 #![forbid(unsafe_code)]
 
 use horizon_platform::hooks::{self, Hooks};
+use horizon_platform::{pages, settings};
 
 /// Every Horizon part in the game, in the order its hooks run.
-const PARTS: [&dyn Hooks; 2] = [
+const PARTS: [&dyn Hooks; 4] = [
     // The anonymous "I'm playing" ping.
     &horizon_heartbeat::HOOKS,
     // Play with Friends: `friend:` addresses join through its tunnel.
     &horizon_friends::game::HOOKS,
+    // The official server in the player's server list.
+    &horizon_official_servers::HOOKS,
+    // "Playing Horizon" on the player's Discord profile.
+    &horizon_discord::HOOKS,
 ];
+/// Their settings, in the player's settings files.
+const STORES: [&dyn settings::Store; 1] = [&horizon_discord::SETTING];
+/// Their rows and pages in the options screens.
+const PAGES: [&dyn pages::Page; 1] = [&horizon_discord::SECTION];
 
 /// Registers Horizon's in-game parts with the game. The executable calls it before it runs the
 /// game, and so does the launcher's generated executable for native mods.
 pub fn register() {
-    for part in PARTS {
-        if let Err(e) = hooks::register(part) {
+    let late = PARTS.into_iter().map(hooks::register);
+    let late = late.chain(STORES.into_iter().map(settings::register));
+    for result in late.chain(PAGES.into_iter().map(pages::register)) {
+        if let Err(e) = result {
             // The executable registered after starting the game: a bug, not a player's problem.
             log::warn!("Horizon: an in-game part did not register: {e}");
         }

crates/horizon-platform/Cargo.toml

@@ -10,7 +10,7 @@ description = "The platform's public API: what the Horizon layer and mods may us
 # Each part of the engine a Horizon crate may reach, so a crate builds only the engine it uses.
 # level.dat, servers.dat and region files: NBT, compression, region read and write.
 world = ["dep:horizon-world"]
-# A server's address after its SRV record, and the offline-mode UUID of a name.
+# A server's address after its SRV record, the offline-mode UUID of a name, and servers.dat.
 protocol = ["world", "dep:horizon-protocol"]
 # Preparing the game's files from the player's own Minecraft install.
 prepare = ["dep:horizon-prepare"]

crates/horizon-platform/src/lib.rs

@@ -46,7 +46,9 @@ pub use horizon_server_files as server_files;
 /// [`hooks::register`] it before the game starts (docs/layers.md, "How a Horizon crate plugs
 /// in"). The engine's dispatch side is not part of the API.
 pub mod hooks {
-    pub use horizon_hooks::{Hooks, Started, TooLate, register, tunnel};
+    pub use horizon_hooks::{
+        Activity, Client, Dimension, GameMode, Hooks, Play, Started, TooLate, register, tunnel,
+    };
 }
 
 /// The settings store (`horizon_hooks::settings`): a crate's own `key:value` lines in the game
@@ -64,3 +66,12 @@ pub mod pages {
 pub mod hud {
     pub use horizon_hooks::hud::{Canvas, Corner, Layer, register};
 }
+
+/// The multiplayer server list as vanilla stores it (`servers.dat`): read, write, add, remove,
+/// and the lock held while it is read and written back.
+#[cfg(feature = "protocol")]
+pub mod servers {
+    pub use horizon_protocol::servers::{
+        ServerEntry, load, lock, parse_address, prepend, remove_where, save,
+    };
+}

docs/forking.md

@@ -22,15 +22,15 @@ What changes in that build:
 | Extra | Where it lives | The gate |
 |---|---|---|
 | Cosmetics, emotes and the emote wheel, "Show me as a Horizon player" | `game/cosmetics.rs` (+ `cosmetics/fx.rs`, `cosmetics/emotes.rs`, `cosmetics/emote_wheel.rs`), crate `horizon-cosmetics` | `game::cosmetics::enabled()`: the service is never asked, nothing is drawn, B opens no wheel |
-| The official server added to the server list, the withdrawn partner server taken out | `official_servers.rs` | the module and its call at startup (`game.rs`, `fn run`) |
-| Horizon Settings (Extras, PvP & HUD, Splitscreen, Studio, AI Agent, Discord) and Mods (with the registry browser) | `options_ui.rs` (`Page::Horizon` and below), `extras_ui.rs`, `extras.rs`, `pvp.rs`, `game/extras.rs`, `game/tweaks.rs`, `extras_hud.rs` | the Options screen shows vanilla's greyed Telemetry Data instead (`options_ui::HORIZON_EXTRAS`, set in `entry.rs`) |
-| Discord Rich Presence | `discord_presence.rs`, `game/discord.rs` | the `discord` feature, which `horizon-extras` turns on |
+| The official server added to the server list, the withdrawn partner server taken out | crate `horizon-official-servers` | registered only by the official executable (`horizon-official`); horizon-client's own executable has none |
+| Horizon Settings (Extras, PvP & HUD, Splitscreen, Studio, AI Agent) and Mods (with the registry browser) | `options_ui.rs` (`Page::Horizon` and below), `extras_ui.rs`, `extras.rs`, `pvp.rs`, `game/extras.rs`, `game/tweaks.rs`, `extras_hud.rs` | the Options screen shows vanilla's greyed Telemetry Data instead (`options_ui::HORIZON_EXTRAS`, set in `entry.rs`) |
+| Discord Rich Presence and its switch | crate `horizon-discord` | registered only by the official executable (`horizon-official`); horizon-client's own executable has none |
 | Play with Friends | hosting: `game/friends.rs`, `game/friends/screen.rs`; joining: crate `horizon-friends` (`game`) | hosting: the `friends` feature (`game/friends_off.rs` stands in); joining: only the official executable registers it ([layers.md](layers.md#how-a-horizon-crate-plugs-in)) |
 | The anonymous "I'm playing" ping | crate `horizon-heartbeat` | not in horizon-client at all: only the official executable (`horizon-official`) registers it ([layers.md](layers.md#how-a-horizon-crate-plugs-in)) |
 
 Credits & Attribution then says where the official build is (`horizon.plain.official`).
 
-`grep -rn horizon-extras crates/` lists every gate. Apart from the three features above, the gates
+`grep -rn horizon-extras crates/` lists every gate. Apart from the `friends` feature above, the gates
 are `cfg!(feature = "horizon-extras")`: both sides compile in every build, so no stub has to follow
 the code it replaces. To remove an extra for good, delete its files from the table and the lines its
 gate guards.

docs/layers.md

@@ -156,9 +156,8 @@ Horizon's own extras and its product, and every built-in address of an outside s
   benchmark uploads, releases and updates, the hosting supervisor, the launcher.
 - **Examples:** `horizon-addresses`, `horizon-cosmetics`, `horizon-friends`, `horizon-relay`, `horizon-telemetry`,
   `horizon-bench`, `horizon-release-sign`, `horizon-server`, `horizon-mod-registry`, `horizon-heartbeat`,
-  `horizon-official`, `launcher/`. Still in engine crates today: `game/cosmetics.rs`, `game/emotes.rs`,
-  `game/discord.rs`, `game/extras.rs`, `game/tweaks.rs`, `multiplayer.rs` (`add_official_server`), `extras_ui.rs`,
-  `pvp.rs`.
+  `horizon-official`, `horizon-official-servers`, `horizon-discord`, `launcher/`. Still in engine crates today:
+  `game/cosmetics.rs`, `game/emotes.rs`, `game/extras.rs`, `game/tweaks.rs`, `extras_ui.rs`, `pvp.rs`.
 - **Rules:**
   - It uses the platform's public API only, never the engine.
   - Until it moves, every Horizon feature in the game sits behind the `horizon-extras` feature
@@ -513,7 +512,7 @@ Horizon's own and third-party addresses (Horizon layer):
 | `cosmetics.playhorizon.dev` | cosmetics, emotes, presence | `horizon-addresses` (#12993) |
 | `telemetry.playhorizon.dev` | opt-in telemetry, the "I'm playing" ping, benchmark uploads | `horizon-addresses` (#12993) |
 | `stun.cloudflare.com`, `stun.l.google.com` | Play with Friends NAT discovery | `horizon-addresses` (#12993) |
-| `afri-network.co.za` | the withdrawn partner server, so the game can remove the entry it added | `multiplayer.rs` (`WITHDRAWN_PARTNER`) |
+| `afri-network.co.za` | the withdrawn partner server, so the game can remove the entry it added | `horizon-addresses` |
 | `horizon-rust.github.io/horizon-mods`, `github.com/horizon-rust/horizon-mods` | the mod registry index and files: a build of this repository alone asks the player for a registry | `mod_registry.rs`, `horizon-mods/src/index*.rs`, `cargo-horizon-mod` |
 | `api.modrinth.com`, `cdn.modrinth.com` | the in-game resource pack browser, modpack porting | `pack_browser.rs`, `horizon-port-pack` |
 | `github.com`, `raw.githubusercontent.com`, `gitlab.com`, `maven.neoforged.net` | modpack porting's sources | `horizon-port-pack` |

docs/native-client.md

@@ -423,13 +423,18 @@ While Discord runs on the same computer, the player's Discord profile shows
 "Playing Horizon" and what they are doing: "In the menus", "Singleplayer",
 "Multiplayer" or "Hosting a world" (with the party size, of 8), the dimension
 ("In the Nether") and the time since they entered the world. It never shows a
-world's name or a server's address. Horizon Settings has the switch
-(**Discord Rich Presence**, on by default; `discordPresence` in
-`horizon-extras.txt`), and `HORIZON_NO_DISCORD=1` turns it off for one run.
+world's name or a server's address. The switch is on the Extras page, in its
+Multiplayer group (**Discord Rich Presence**, on by default; `discordPresence`
+in `horizon-extras.txt`, the first splitscreen player's), and
+`HORIZON_NO_DISCORD=1` turns it off for one run.
 
-`crates/horizon-client/src/discord_presence.rs` speaks Discord's local IPC
-itself (the `discord-ipc-N` socket or named pipe, no SDK) from a thread of its
-own: the frame only hands it a status when it changes. It retries every 15 s
+The crate `horizon-discord` (Horizon layer) speaks Discord's local IPC itself
+(the `discord-ipc-N` socket or named pipe, no SDK) from a thread of its own.
+The game hands it a status only when it changes, through the platform's
+`activity` hook (`game/activity.rs` says what the player does), and keeps the
+switch itself: its settings store and its Extras row (the platform's settings
+and pages registries). Only the official executable (`horizon-official`)
+registers it: horizon-client's own executable shows no presence and no switch. It retries every 15 s
 while Discord isn't running and stays within Discord's 5 updates per 20 s.
 Dedicated servers never start it, and automated runs (offscreen, benchmarks)
 only talk to a fake Discord: `lab.game_env` sets `HORIZON_NO_DISCORD=1`, and

docs/server.md

@@ -427,8 +427,8 @@ game built in `Game::new`, the integrated server on its own thread. On that base
 **Binaries.** The release archives hold `horizon-client`, `horizon-ctl`, `horizon-prepare` and
 `horizon-server`. On Linux the release also has `horizon-server-linux-x86_64.tar.gz`: `horizon-server`,
 `horizon-prepare` and `horizon-engine`, the game built with `--no-default-features` (no sound, no
-controllers, no Discord presence or Play with Friends: the `discord` and `friends` features; nor the "I'm
-playing" ping, which only the official executable has), which links neither `libasound.so.2` nor `libudev.so.1`. `release.yml` builds it after the
+controllers, no Play with Friends: the `friends` feature; nor Discord presence or the "I'm playing" ping, which
+only the official executable has), which links neither `libasound.so.2` nor `libudev.so.1`. `release.yml` builds it after the
 client archive (`xtask package-server`) and fails if `tools/check_imports.py --server` finds either library;
 CI lints the same build. `horizon-server` runs `horizon-engine` when it is beside it or on the PATH, else
 `horizon-client`. Build it yourself with `cargo build --release -p horizon-client --no-default-features`

tools/addresses.json

@@ -49,7 +49,6 @@
     "crates/horizon-client/src/mod_registry.rs horizon-rust.github.io",
     "crates/horizon-client/src/mod_registry.rs playhorizon.dev",
     "crates/horizon-client/src/no_resources.rs playhorizon.dev",
-    "crates/horizon-client/src/official_servers.rs afri-network.co.za",
     "crates/horizon-mod-registry/src/github.rs api.github.com",
     "crates/horizon-mod-registry/src/github.rs github.com",
     "crates/horizon-mod-registry/src/github.rs uploads.github.com",

tools/discord_presence_e2e.py

@@ -9,7 +9,7 @@ The game goes title -> world -> Nether -> quit through horizon-ctl, and the acti
     single     single player on its server thread
     lan        a host opens its world to LAN and a guest joins: the guest shows "Multiplayer",
                the host "Hosting a world" with a party of 2 of 8
-    setting    off in horizon-extras.txt: nothing reaches Discord; the Horizon Settings switch
+    setting    off in horizon-extras.txt: nothing reaches Discord; the Extras switch
                turns it on (the activity appears) and off (it is cleared)
     late       Discord starts after the game: found within the 15 s retry
 
@@ -136,7 +136,7 @@ class Game:
             self.discord.start()
         extra = {'HORIZON_HOME': self.home, 'HORIZON_TELEMETRY_URL': 'off', 'HORIZON_DISCORD_IPC_DIR': self.discord.dir}
         self.env = lab.game_env(**extra)
-        self.ctl_run('launch', '--offscreen', '--game', str(bins / 'horizon-client'), '--resources',
+        self.ctl_run('launch', '--offscreen', '--game', str(bins / 'horizon-official'), '--resources',
                      str(lab.RESOURCES.resolve()), *args)
 
     def ctl_run(self, *words, timeout=600):
@@ -208,7 +208,7 @@ def lan(bins):
 
 
 def setting(bins):
-    """Off in horizon-extras.txt: Discord never hears from the game. Turned on in Horizon Settings: the
+    """Off in horizon-extras.txt: Discord never hears from the game. Turned on in Extras: the
     activity appears; off again: it is cleared."""
     game = Game(bins, 'setting', extras='discordPresence:false\n')
     d = game.discord
@@ -216,7 +216,7 @@ def setting(bins):
         game.ctl_run('wait-for', 'screen', 'title')
         time.sleep(3)
         assert not d.handshakes and not d.activities, (d.handshakes, d.activities)
-        game.ctl_run('options', 'horizon')
+        game.ctl_run('options', 'extras')
         switch = next(w for w in game.ctl_run('ui')['widgets'] if w.get('label', '').startswith('Discord Rich'))
         assert switch['label'] == 'Discord Rich Presence: Off', switch
         game.ctl_run('click', switch['id'])
@@ -251,14 +251,14 @@ CHECKS = {'single': single, 'lan': lan, 'setting': setting, 'late': late}
 def main():
     parser = argparse.ArgumentParser(description=__doc__, formatter_class=argparse.RawDescriptionHelpFormatter)
     parser.add_argument('--check', choices=[*CHECKS, 'all'], default='all')
-    parser.add_argument('--bin-dir', help='prebuilt horizon-client and horizon-ctl (default: build with the fast profile)')
+    parser.add_argument('--bin-dir', help='prebuilt horizon-official and horizon-ctl (default: build with the fast profile)')
     args = parser.parse_args()
     if sys.platform == 'win32':
         sys.exit('the fake Discord is a Unix socket: macOS or Linux only')
     if args.bin_dir:
         bins = Path(args.bin_dir).resolve()
     else:
-        subprocess.run(['cargo', 'build', '--locked', '--profile', 'fast', '-p', 'horizon-client', '-p', 'horizon-client-lib', '--bins'],
+        subprocess.run(['cargo', 'build', '--locked', '--profile', 'fast', '-p', 'horizon-official', '-p', 'horizon-client-lib', '--bins'],
                        cwd=ROOT, check=True)
         meta = json.loads(subprocess.run(['cargo', 'metadata', '--format-version', '1', '--no-deps'], cwd=ROOT,
                                          capture_output=True, text=True, check=True).stdout)

tools/layers.json

@@ -51,11 +51,13 @@
     "horizon-addresses": "horizon",
     "horizon-bench": "horizon",
     "horizon-cosmetics": "horizon",
+    "horizon-discord": "horizon",
     "horizon-friends": "horizon",
     "horizon-heartbeat": "horizon",
     "horizon-launcher": "horizon",
     "horizon-mod-registry": "horizon",
     "horizon-official": "horizon",
+    "horizon-official-servers": "horizon",
     "horizon-relay": "horizon",
     "horizon-release-sign": "horizon",
     "horizon-server": "horizon",

tools/port_map/game-005.tsv

@@ -46,7 +46,7 @@ Entity.dropAllLeashConnections	port	crates/horizon-client/src/game/leads.rs::Gam
 Entity.canCollideWith	inline	crates/horizon-client/src/game/ghasts.rs::Game::player_entity_collisions	gap: player: the entities a player cannot walk through are boats and happy ghasts only; a live shulker (canBeCollidedWith) is not solid, so the player walks through it
 Entity.getDefaultPassengerAttachmentPoint	inline	crates/horizon-client/src/mobs/riders.rs::passenger_attachment	one point per vehicle, so the passenger index is always 0; default is the top of the box
 Entity.ejectPassengers	port	crates/horizon-client/src/game/boat_passengers.rs::Game::eject_boat_mobs	gap: minor: boats place riders at the dismount spot; when a mob vehicle dies sync_riders only lets go and the rider stays where it was seated
-Entity.removeVehicle	inline	crates/horizon-client/src/game/commands/world_cmds.rs::Game::dismount_mob	gap: minor: no entity_dismount game event, so sculk sensors and wardens never hear a dismount
+Entity.removeVehicle	port	crates/horizon-client/src/game/sculk.rs::Game::mount_events	`startRiding`/`removeVehicle`: `entity_mount` at the new vehicle and `entity_dismount` at the old one, derived from the vehicle the rider had last tick, for players and mobs
 Entity.moveOrInterpolateTo	port	crates/horizon-world/src/stepped_interpolation.rs::SteppedInterpolation::interpolate_to	living entities from a server; boats and other objects use a three tick Lerp
 Entity.getHandHoldingItemAngle	port	crates/horizon-client/src/game/fireworks.rs::Game::rocket_hand_angle	ticked in #3514; `Entity.getHandHoldingItemAngle` is cited at crates/horizon-client/src/game/fireworks.rs:241
 Entity.teleportToPortalDestination	inline	crates/horizon-client/src/game/nether_portal.rs::Game::send_through_portal	may_enter checks isAllowedToEnterPortal; the entity is saved and waits for its dimension

tools/port_map/game-006.tsv

@@ -62,7 +62,7 @@ LivingEntity.dropFromShearingLootTable	port	crates/horizon-client/src/game/creat
 LivingEntity.getFallDamageSound	inline	crates/horizon-client/src/mobs/landing.rs::MobLanding::living_fall_sound	a monster gets entity.hostile.big_fall and entity.hostile.small_fall, anything else the generic pair; a player's comes from landing.rs
 LivingEntity.getHitbox	missing		minor: a rider's hitbox is not cut at its seat height; spear and melee tests use the full box
 LivingEntity.postPiercingAttack	port	crates/horizon-client/src/game/enchant_effects.rs::Game::post_piercing_attack	Lunge's dash after a jab
-LivingEntity.trapdoorUsableAsLadder	port	crates/horizon-world/src/climbing.rs::on_climbable	gap: minor: the player only; a mob's ai.rs::on_climbable checks the climbable tag at its feet, no open trapdoor over a ladder
+LivingEntity.trapdoorUsableAsLadder	port	crates/horizon-world/src/climbing.rs::on_climbable	the climbable tag, or an open trapdoor directly over a ladder with the same facing: `climbing::on_climbable` for the player and `Mob::on_climbable` for mobs
 LivingEntity.isAlive	port	crates/horizon-client/src/mobs.rs::Mob::alive	not removed and health above zero
 LivingEntity.setIgnoreFallDamageFromCurrentImpulse	port	crates/horizon-world/src/living_fall.rs::ImpulseContext::set_ignore_fall_damage	40 ticks of grace
 LivingEntity.getDamageAfterArmorAbsorb	inline	crates/horizon-client/src/mobs.rs::Mob::damage_with	the player's armor wear is health.rs hurt_armor; the mob path also scales armor effectiveness (breach)

tools/port_map/game2-006.tsv

@@ -31,7 +31,7 @@ Projectile.onAboveBubbleColumn	port	crates/horizon-client/src/projectiles.rs::Pr
 Projectile.onInsideBubbleColumn	port	crates/horizon-client/src/projectiles.rs::Projectile::bubble_column_push	unclamped 0.06 up (0.03 down) inside a column; arrows in arrows.rs::Ticker::bubble_column
 Projectile.canBreakBlockInAdventureMode	port	crates/horizon-client/src/game/creatures.rs::Game::projectile_breaks_block	gap: minor: the shooter's gamemode and kind decide it; a stack's `can_break` predicate is not consulted
 Projectile.spawnProjectileFromRotation	port	crates/horizon-client/src/projectiles.rs::Projectile::shoot_from_rotation	gap: minor: the aim and inherited velocity only; the add-to-world step is the caller's
-Projectile.spawnProjectile	inline	crates/horizon-client/src/game/creatures.rs::Game::throw_item	each shooter adds its own projectile (throw_item, shoot_crossbow, shoot_projectile_item, the bow in game.rs); throw_item is the player throw path
+Projectile.spawnProjectile	inline	crates/horizon-client/src/game/creatures.rs::Game::throw_item	each shooter adds its own projectile (throw_item, shoot_crossbow, shoot_projectile_item, the bow in game/use_hand.rs::release_bow); throw_item is the player throw path
 Projectile.applyOnProjectileSpawned	port	crates/horizon-client/src/game/enchant_effects.rs::Game::ignite_spawned_arrow	gap: minor: Flame ignite only; Piercing and Punch go through Projectile::set_bonus
 Projectile.hitTargetOrDeflectSelf	port	crates/horizon-client/src/game/creatures.rs::Game::tick_projectiles	gap: minor: deflection is checked for breezes only; the onHit dispatch is creatures.rs projectile_hit
 Projectile.onRedirectProjectile	port	crates/horizon-client/src/game/deflect.rs::Game::deflect	gap: minor: the player's attack turns the projectile; a projectile hitting another redirectable one is not modelled