Merge branch 'perf/idle-generator-scratch' into HEAD

minecart: right-clicking a tnt minecart uses the held item, so a crossbow shoots at it

.claude/skills/vanilla-parity/SKILL.md

@@ -0,0 +1,76 @@
+---
+name: vanilla-parity
+description: Fix a Horizon bug or gap so it behaves 1:1 like vanilla 26.3, starting from the port ledger (tools/port_ledger.py) instead of grepping. Use for any issue, Discord report or PR that makes Horizon match vanilla: "X doesn't work like in Java", a missing sound, particle, animation, mob behaviour, block rule, screen or packet.
+---
+
+# Vanilla parity with the port ledger
+
+The port ledger pairs every vanilla method with the Rust fn that ports it (or says it is missing, or needs
+no port) and lists where a port isn't wired like vanilla. Ask it first; grep only for what it can't answer.
+Full reference: `docs/port-ledger.md`.
+
+## 0. Have a fresh ledger
+
+```sh
+python3 tools/port_ledger.py build          # ~20 s; again after pulling main
+```
+
+It needs the vanilla jar (the launcher's `versions/26.3/26.3.jar`, or `--jar`) and/or the lab's decompiled
+sources (`python3 tools/lab.py decompile`, or `--sources DIR`). If `build` says it has no vanilla code, run
+the lab first; don't guess vanilla from memory.
+
+## 1. From the report to the code
+
+```sh
+python3 tools/port_ledger.py issue 3236                      # a GitHub issue number
+python3 tools/port_ledger.py issue "mooshroom stays red after lightning"   # or the report's text
+```
+
+It ranks the vanilla classes the report names and lists, per class, its Rust home files, where each method is
+ported, and the known gaps (`missing` rows from the verdict map, seam/client/drift gaps). Often the cause is
+already written there ("Type is not saved"). Then drill in:
+
+```sh
+python3 tools/port_ledger.py where MushroomCow.readAdditionalSaveData   # ports, callers, callees, gaps
+python3 tools/port_ledger.py class MushroomCow                          # every method: where, or missing
+python3 tools/port_ledger.py what crates/horizon-client/src/mobs/farm.rs:120   # which vanilla method a fn ports
+```
+
+A ledger answer is a lead, not a verdict: about 1 in 12 map rows is wrong. Read the vanilla method (path and
+line are in the output) and the Rust fn before changing anything.
+
+## 2. Port it the vanilla way
+
+- Translate the vanilla method, don't reinvent it: same order of operations, same constants, the same random
+  draws in the same order (`horizon_core::random`), Java `Math` through `horizon_core::jmath`.
+- Open the fn's doc with the vanilla method it ports: `` /// `MushroomCow.readAdditionalSaveData`: ... ``.
+  That one line is what makes the next agent find it.
+- Fix the path players run: single player is a client of the integrated server, so server logic lives in
+  `game/lan*.rs` and `src/lan/`, and what only the client's copy shows (particles, local sounds, hand
+  animation) must be reached from `game/remote*.rs`. A fix on the old in-frame path alone fixes nothing.
+- Look at the neighbours the ledger lists for the same class: a `client` or `seam` gap next to your fix is
+  usually the same bug on the other path.
+
+## 3. Before the PR
+
+```sh
+python3 tools/port_ledger.py check --base origin/main
+```
+
+It lists the ports your branch touches with their open gaps, citations to add, stale citations, and (against
+the base) the gaps the branch closes and opens. Close what belongs to your fix, cite what you ported, leave
+no new stale citation. If you ported a method the verdict map called `missing`, change its row in
+`tools/port_map/*.tsv` to `port` with the fn (`file.rs::Owner::fn`) and run
+`python3 tools/port_ledger.py map-check tools/port_map/<file>.tsv`.
+
+Then the usual: the harness for the area (`docs/architecture.md`), `cargo check`/tests per `AGENTS.md`, and
+a small PR that says which vanilla method it now matches.
+
+## Finding work
+
+```sh
+python3 tools/port_ledger.py gaps --kind seam      # ported on two paths, wired on one: the best leads
+python3 tools/port_ledger.py gaps --kind client    # client-only effects the server path never reaches
+python3 tools/port_ledger.py gaps --kind drift     # a port missing a sound, particle, item or constant
+rg -n "player:" tools/port_map/*.tsv               # missing behaviour a player would see
+```

.githooks/pre-commit

@@ -1,2 +1,11 @@
 #!/bin/sh
-exec python3 tools/check_public_tree.py
+# Git for Windows puts a `python3` on PATH that is only the Microsoft Store
+# stub: it prints "Python" and exits non-zero, so the hook fails with no other
+# output. Use the first name that actually runs Python 3.
+for py in python3 python py; do
+    if "$py" -c "import sys; sys.exit(sys.version_info < (3,))" >/dev/null 2>&1; then
+        exec "$py" tools/check_public_tree.py
+    fi
+done
+echo "check_public_tree: no working Python 3 found" >&2
+exit 1

.githooks/pre-push

@@ -1,2 +1,11 @@
 #!/bin/sh
-exec python3 tools/check_public_tree.py --pre-push
+# Git for Windows puts a `python3` on PATH that is only the Microsoft Store
+# stub: it prints "Python" and exits non-zero, so the hook fails with no other
+# output. Use the first name that actually runs Python 3.
+for py in python3 python py; do
+    if "$py" -c "import sys; sys.exit(sys.version_info < (3,))" >/dev/null 2>&1; then
+        exec "$py" tools/check_public_tree.py --pre-push
+    fi
+done
+echo "check_public_tree: no working Python 3 found" >&2
+exit 1

.github/pull_request_template.md

@@ -1,7 +1,21 @@
+<!-- Opened by an AI agent? First line: "> 🤖 Opened by <your GitHub login>'s AI agent (<tool, model>), not by <your GitHub login> personally." Use your own login, not someone else's. -->
+
 ## What and why
 
 <!-- What this changes, and why. Link the issue it fixes ("Fixes #123"). -->
 
+## Kind
+
+<!-- Tick one: it sets the pull request's label (CONTRIBUTING.md "Pull requests"). -->
+
+- [ ] parity: Horizon now does what vanilla 26.3 does
+- [ ] bug: a crash or a breakage
+- [ ] perf: faster, or less memory
+- [ ] feature: something new for players (listed under New in the release notes)
+- [ ] extra: Horizon-only, off by default
+- [ ] tooling: tools, CI, tests, harnesses
+- [ ] docs
+
 ## Vanilla reference
 
 <!-- The vanilla classes and methods this follows (tools/rea_vanilla.py), and the harness that checks it.

.github/trusted-reviewers.txt

@@ -0,0 +1,9 @@
+# Trusted reviewers: one list for two things (docs/release-flow.md "Trusted reviewers").
+# - `/nightly 2640 2642` picks the pull requests the Nightly holds (tools/ci/nightly_set.py);
+# - `/close`, `/reopen`, `/label`, `/unlabel` triage issues and pull requests (tools/ci/triage_command.py).
+# Ludovic is always allowed and isn't listed. One GitHub login per line, with who added it and when. Removing a
+# line revokes that login at once. A line with only `paused` stops both for every reviewer (Ludovic's still work).
+kacpherek    # added by Ludovic, 2026-10-27
+rdbtCVS      # added by Ludovic, 2026-10-27
+Online5277   # added by Ludovic, 2026-10-27 (his top three by merged pull requests)
+levzzz5154   # added by Ludovic, 2026-10-28 (Horizon Team; author of horizon-mixins)

.github/workflows/cancel-on-close.yml

@@ -16,12 +16,14 @@ jobs:
           GH_TOKEN: ${{ github.token }}
           REPO: ${{ github.repository }}
           BRANCH: ${{ github.event.pull_request.head.ref }}
-          SHA: ${{ github.event.pull_request.head.sha }}
+          HEAD_REPO: ${{ github.event.pull_request.head.repo.full_name }}
         run: |
+          # Every head the pull request had, not only its last: a run-parity label added on an older head left that
+          # run queued after the merge (#3104, 2026-10-29). Its branch in its own repository names its runs (another
+          # fork can have a branch of the same name).
           for status in queued in_progress waiting pending requested; do
-            gh run list -R "$REPO" --branch "$BRANCH" --status "$status" --limit 100 \
-              --json databaseId,event,headSha \
-              -q ".[] | select(.event == \"pull_request\" and .headSha == \"$SHA\") | .databaseId"
+            gh api -X GET "repos/$REPO/actions/runs" -f branch="$BRANCH" -f event=pull_request -f status="$status" \
+              -f per_page=100 --jq ".workflow_runs[] | select(.head_repository.full_name == \"$HEAD_REPO\") | .id"
           done | sort -u | while read -r id; do
             gh run cancel -R "$REPO" "$id" || true
           done

.github/workflows/ci.yml

@@ -51,7 +51,7 @@ jobs:
         if: steps.rust.outputs.required != 'false'
         run: |
           sudo apt-get update && sudo apt-get install -y --no-install-recommends libasound2-dev libudev-dev
-          rustup toolchain install stable --profile minimal --component rustfmt --component clippy --target wasm32-unknown-unknown
+          rustup toolchain install stable --profile minimal --component rustfmt --component clippy
       # Dependencies and the workspace's own build, saved from main's runs (pull requests read main's cache).
       - uses: Swatinem/rust-cache@v2
         if: steps.rust.outputs.required != 'false'
@@ -62,8 +62,7 @@ jobs:
         if: steps.rust.outputs.required != 'false'
         run: |
           cargo +stable fmt --all -- --check
-          # With the game's code mods (on in every release build, off by default).
-          cargo +stable clippy --workspace --all-targets --features horizon-client/mods -- -D warnings
+          cargo +stable clippy --workspace --all-targets -- -D warnings
           # The server build (released as horizon-engine): the game without sound or controllers.
           cargo +stable clippy -p horizon-client --all-targets --no-default-features -- -D warnings
       # Libraries, binaries and integration tests, then doc tests: not the ~275 examples, which clippy above already
@@ -71,8 +70,47 @@ jobs:
       - name: Test Rust core and voxel kernel correctness
         if: steps.rust.outputs.required != 'false'
         run: |
-          cargo +stable test --workspace --lib --bins --tests --features horizon-client/mods,horizon-mods/pack
-          cargo +stable test --workspace --doc --features horizon-client/mods,horizon-mods/pack
+          cargo +stable test --workspace --lib --bins --tests
+          # The full content-root tests (#[ignore]d: minutes each on a laptop). The same build as above; they need the
+          # prepared vanilla data, so without it they pass at once.
+          cargo +stable test --workspace --lib mod_content::tests:: -- --ignored
+          cargo +stable test --workspace --doc
+  # The launcher is its own workspace (launcher/Cargo.toml), so verify's cargo runs never build it. A pull request that
+  # changes it or a crate it builds is checked here, and so is every push to main: two pull requests can each pass
+  # alone and break it together (#2059 and the registry ratings did, 2026-10-26).
+  launcher:
+    runs-on: ubuntu-latest
+    timeout-minutes: 30
+    steps:
+      - uses: actions/checkout@v4
+        with:
+          fetch-depth: 0
+      - name: Does this pull request change the launcher or a crate it builds?
+        if: github.event_name == 'pull_request'
+        id: launcher
+        env:
+          BASE_SHA: ${{ github.event.pull_request.base.sha }}
+          HEAD_SHA: ${{ github.event.pull_request.head.sha }}
+        run: python3 tools/ci/rust_changes.py --launcher "$BASE_SHA" "$HEAD_SHA" >> "$GITHUB_OUTPUT"
+      - name: Install Rust and the headers GPUI links against
+        if: steps.launcher.outputs.required != 'false'
+        run: |
+          sudo apt-get update && sudo apt-get install -y --no-install-recommends libxkbcommon-x11-dev libwayland-dev \
+            libx11-xcb-dev libfontconfig-dev libvulkan-dev libasound2-dev libudev-dev
+          rustup toolchain install stable --profile minimal --component rustfmt --component clippy
+      - uses: Swatinem/rust-cache@v2
+        if: steps.launcher.outputs.required != 'false'
+        with:
+          workspaces: launcher
+          shared-key: launcher
+          save-if: ${{ github.ref == 'refs/heads/main' }}
+      - name: Check the launcher's formatting, lint and tests
+        if: steps.launcher.outputs.required != 'false'
+        working-directory: launcher
+        run: |
+          cargo +stable fmt --check
+          cargo +stable clippy --all-targets --locked -- -D warnings
+          cargo +stable test --locked --lib
   # Most pull requests leave the harnesses to parity-main, which runs them on main a batch of merges at a time
   # (.github/workflows/parity-main.yml; releases wait for it). A pull request still runs them itself when it changes
   # a harness, an oracle, a probe or the runner, or carries the run-parity label (run-parity.yml, when it is added).
@@ -108,6 +146,7 @@ jobs:
     with:
       base: ${{ github.event.pull_request.base.sha }}
       head: ${{ github.event.pull_request.head.sha }}
+      full: ${{ contains(github.event.pull_request.labels.*.name, 'full-parity') }}
   # Horizon never downloads the game. These jobs need a self-hosted Linux runner
   # (label horizon-game) holding the maintainer's own copy: the official launcher's
   # game directory in HORIZON_MINECRAFT_DIR and the pinned server jar in

.github/workflows/claim-command.yml

@@ -0,0 +1,74 @@
+name: claim command
+# `/claim` and `/unclaim` comments: anyone takes an issue before working on it, and a daily run releases the claims
+# older than 5 days that no open pull request links (CONTRIBUTING.md "Claim before you start",
+# tools/ci/claim_command.py).
+#
+# Why no pull request's code runs here, though the token can write:
+# - `issue_comment` and `schedule` always run this file from main, whoever comments and wherever.
+# - It checks out main's script and list only, never a pull request; it reads threads through the API.
+# - The comment's text and author reach the script as env vars, never in a shell line. The token stays in the step
+#   and can only write issues (assignees, comments, reactions).
+on:
+  issue_comment:
+    types: [created]
+  schedule:
+    - cron: "23 5 * * *"
+  workflow_dispatch:
+permissions:
+  contents: read
+jobs:
+  command:
+    # Every other comment skips here, before a runner starts. Pull requests are answered by the script.
+    if: >-
+      github.event_name == 'issue_comment' && github.event.comment.user.type != 'Bot' && (
+      startsWith(github.event.comment.body, '/claim') ||
+      startsWith(github.event.comment.body, '/unclaim'))
+    # One command per issue at a time, so two `/claim`s can't both find it free. On the job, not the workflow:
+    # the skipped runs of ordinary comments must not cancel a waiting one.
+    concurrency:
+      group: claim-${{ github.event.issue.number }}
+    runs-on: ubuntu-latest
+    timeout-minutes: 5
+    permissions:
+      contents: read
+      issues: write
+    steps:
+      - uses: actions/checkout@v4
+        with:
+          ref: main
+          persist-credentials: false
+          sparse-checkout: |
+            .github/trusted-reviewers.txt
+            tools/ci/nightly_set.py
+            tools/ci/claim_command.py
+          sparse-checkout-cone-mode: false
+      - name: Run the command
+        env:
+          GH_TOKEN: ${{ github.token }}
+          BODY: ${{ github.event.comment.body }}
+          AUTHOR: ${{ github.event.comment.user.login }}
+          ISSUE: ${{ github.event.issue.number }}
+          COMMENT_ID: ${{ github.event.comment.id }}
+          REPO: ${{ github.repository }}
+        run: python3 tools/ci/claim_command.py command
+  release:
+    if: github.event_name != 'issue_comment' && github.repository == 'horizon-rust/horizon'
+    runs-on: ubuntu-latest
+    timeout-minutes: 10
+    permissions:
+      contents: read
+      issues: write
+    steps:
+      - uses: actions/checkout@v4
+        with:
+          ref: main
+          persist-credentials: false
+          sparse-checkout: |
+            tools/ci/nightly_set.py
+            tools/ci/claim_command.py
+          sparse-checkout-cone-mode: false
+      - name: Release stale claims
+        env:
+          GH_TOKEN: ${{ github.token }}
+          REPO: ${{ github.repository }}
+        run: python3 tools/ci/claim_command.py release

.github/workflows/game-build.yml

@@ -0,0 +1,290 @@
+name: game build
+# Builds the game for every platform from `ref`: the Java exporters, then Linux and the Linux server and Windows on
+# GitHub, macOS on the Mac mini's runner with a 1500-frame offscreen run of a new world (smoke-test.json). Called by
+# release.yml (the releases) and nightly-build.yml (the opt-in Nightly), always from main's copy of this file: the
+# caller's commit, never the one being built. It holds no secrets: signing the checksums is the callers' own job,
+# which never runs what this one built. See docs/release-flow.md.
+on:
+  workflow_call:
+    inputs:
+      ref:
+        description: The commit to build
+        type: string
+        required: true
+      version:
+        description: The version built in (HORIZON_VERSION), e.g. 0.2.81 or nightly-2026-10-28
+        type: string
+        required: true
+      nightly:
+        description: A nightly's "<date> <short sha>" (HORIZON_NIGHTLY), shown by the game; empty for a release
+        type: string
+        default: ''
+      trusted:
+        # Only release.yml says true: it builds main. A nightly can hold pull requests nobody reviewed yet, whose
+        # build scripts and tests run here and could rewrite target/, the cargo home or a compiler cache. So an
+        # untrusted build never runs on the release runner, never saves the Rust cache (its key is its own anyway),
+        # and a trusted one never reads the machine's shared sccache, which pull requests' jobs write
+        # (tests/test_nightly.py pins all of it).
+        description: The source is main (a release); false for anything else (a nightly)
+        type: boolean
+        default: false
+      developer_id:
+        description: Sign the macOS programs with Developer ID and notarize the zip (the runner's keychain)
+        type: boolean
+        default: true
+permissions:
+  contents: read
+jobs:
+  exporters:
+    # This runner holds the maintainer's own pinned Minecraft jars. Only our classes leave it. An untrusted build
+    # goes to the Mac mini's nightly runner (macOS + horizon-nightly: ludovics-mac-mini-nightly, beside the one that
+    # runs pull requests' parity jobs, so a nightly never waits behind their queue), never the release runner
+    # (MAC_RUNNER: ludovics-mac-mini-release) nor parity-main's.
+    runs-on: ${{ inputs.trusted && vars.MAC_RUNNER || fromJSON('["self-hosted", "macOS", "horizon-nightly"]') }}
+    # Three full preparations (two isolated, one batched) besides the compile.
+    timeout-minutes: 60
+    steps:
+      - uses: actions/checkout@v4
+        with:
+          ref: ${{ inputs.ref }}
+          persist-credentials: false
+          clean: true
+      - uses: dtolnay/rust-toolchain@stable
+      - run: bash tools/ci/runner-env.sh
+        env:
+          HORIZON_NO_SCCACHE: ${{ inputs.trusted && '1' || '' }}
+      - run: bash tools/ci/vanilla-data.sh
+      - name: Compile and validate original exporters against the pinned jars
+        shell: bash
+        run: |
+          set -euo pipefail
+          # target/ is gone after the clean checkout, and vanilla-data.sh builds the preparer only when it
+          # prepares afresh.
+          cargo build --release --locked -p horizon-prepare
+          # Compiled here, never taken from the runner's shared preparations: pull requests' parity jobs
+          # write those (vanilla-data.sh links .local/exporters to them).
+          rm -rf .local/exporters
+          bundle=$(target/release/horizon-prepare compile-exporters --root "$PWD" | tail -1)
+          mkdir -p exporters
+          cp -R "$bundle/server" "$bundle/client" "$bundle/manifest.json" exporters/
+          # Only our classes and their manifest leave this runner.
+          stray=$(find exporters -type f ! -path exporters/manifest.json \
+            ! \( -name '*.class' \( -path 'exporters/server/dev/horizonlab/parity/*' -o -path 'exporters/client/dev/horizonlab/parity/*' \) \))
+          [ -z "$stray" ] || { echo "::error::not one of our classes: $stray"; exit 1; }
+          python3 tools/check_prepare_exporters.py --binary target/release/horizon-prepare
+      - uses: actions/upload-artifact@v4
+        with:
+          name: original-exporters
+          path: exporters/
+          if-no-files-found: error
+          retention-days: 3
+
+  build:
+    needs: exporters
+    name: build ${{ matrix.name }}
+    strategy:
+      fail-fast: false
+      matrix:
+        include:
+          - name: linux
+            os: ubuntu-22.04
+            dir: horizon-linux-x86_64
+            asset: horizon-linux-x86_64.tar.gz
+            # The server build too: packaging/server/install.sh installs it on Linux.
+            server_dir: horizon-server-linux-x86_64
+            server_asset: horizon-server-linux-x86_64.tar.gz
+          - name: windows
+            os: windows-latest
+            dir: horizon-windows-x64
+            asset: horizon-windows-x64.zip
+            exe: .exe
+            # The C runtime linked in, so the game runs without the Visual C++ redistributable.
+            rustflags: -C target-feature=+crt-static
+          - name: macos
+            mac: true
+            dir: horizon-macos-arm64
+            asset: horizon-macos-arm64.zip
+    runs-on: ${{ matrix.mac && (inputs.trusted && vars.MAC_RUNNER || fromJSON('["self-hosted", "macOS", "horizon-nightly"]')) || matrix.os }}
+    # Notarizing the zip can take a few minutes.
+    timeout-minutes: ${{ matrix.mac && 60 || 40 }}
+    env:
+      RUSTFLAGS: ${{ matrix.rustflags }}
+      # The release's version, built in (horizon_core::release): --version, user agents, crash reports and
+      # telemetry say it. No version-bump commits.
+      HORIZON_VERSION: ${{ inputs.version }}
+      # A nightly's date and commit ("2026-10-28 0c02067"), which the game shows; empty for a release.
+      HORIZON_NIGHTLY: ${{ inputs.nightly }}
+    defaults:
+      run:
+        shell: bash
+    steps:
+      - uses: actions/checkout@v4
+        with:
+          ref: ${{ inputs.ref }}
+          persist-credentials: false
+          # Always from a clean checkout, the Mac mini's runner too: its work folder is shared with pull requests'
+          # parity jobs, and nothing they leave (target/, an untracked .cargo/config.toml, a build script's output)
+          # may end up in a release. target/ is rebuilt from scratch; .local/ is relinked by vanilla-data.sh, which
+          # keeps its preparations outside the checkout.
+          clean: true
+      - uses: dtolnay/rust-toolchain@stable
+      - uses: Swatinem/rust-cache@v2
+        if: runner.environment == 'github-hosted'
+        with:
+          # A release restores only what a release saved: an untrusted build has its own key and saves nothing.
+          shared-key: ${{ inputs.trusted && 'release' || 'nightly' }}-${{ matrix.name }}
+          save-if: ${{ inputs.trusted }}
+      - name: ALSA and udev headers
+        if: runner.os == 'Linux'
+        run: sudo apt-get update && sudo apt-get install -y --no-install-recommends libasound2-dev libudev-dev
+      - name: Build the client, horizon-ctl, horizon-prepare and horizon-server
+        run: cargo build --release --locked -p horizon-client --bin horizon-client --bin horizon-ctl -p horizon-prepare --bin horizon-prepare -p horizon-server --bin horizon-server
+      - name: Every program the release folder takes was built
+        run: |
+          for binary in horizon-client horizon-ctl horizon-prepare horizon-server; do
+            test -f "target/release/$binary${{ matrix.exe }}" || { echo "::error::target/release/$binary${{ matrix.exe }} is missing"; exit 1; }
+          done
+      - name: The signing keychain, unlocked
+        if: runner.os == 'macOS' && vars.MACOS_SIGN_IDENTITY != '' && inputs.developer_id
+        env:
+          MACOS_SIGN_IDENTITY: ${{ vars.MACOS_SIGN_IDENTITY }}
+        run: packaging/macos/keychain.sh unlock
+      - name: Signed with Developer ID and the hardened runtime
+        # Before the checks below, so they run the programs as players will.
+        if: runner.os == 'macOS' && vars.MACOS_SIGN_IDENTITY != '' && inputs.developer_id
+        env:
+          MACOS_SIGN_IDENTITY: ${{ vars.MACOS_SIGN_IDENTITY }}
+        run: |
+          for binary in horizon-client horizon-ctl horizon-prepare horizon-server; do
+            codesign --force --options runtime --timestamp --keychain "$MACOS_SIGN_KEYCHAIN" \
+              --identifier "dev.horizon.${binary#horizon-}" --sign "$MACOS_SIGN_IDENTITY" "target/release/$binary"
+            codesign --verify --strict --verbose=2 "target/release/$binary"
+          done
+      - name: Only system libraries
+        # Windows: no non-system DLL (a "DLL not found" dialog on some players' machines). Linux: the standard
+        # loader and libraries every desktop distribution has. macOS: only the system's own libraries.
+        run: |
+          for binary in horizon-client horizon-ctl horizon-prepare horizon-server; do
+            file="target/release/$binary${{ matrix.exe }}"
+            if [[ "$RUNNER_OS" == macOS ]]; then
+              others=$(otool -L "$file" | tail -n +2 | awk '{print $1}' | grep -v -E '^(/usr/lib/|/System/Library/)' || true)
+              [[ -z "$others" ]] || { echo "::error::$binary links $others"; exit 1; }
+            else
+              ${{ runner.os == 'Windows' && 'python' || 'python3' }} tools/check_imports.py "$file"
+            fi
+          done
+      - name: Every program starts
+        run: |
+          set -euo pipefail
+          bin=target/release
+          "$bin/horizon-client${{ matrix.exe }}" --help | grep -q -- '--resources'
+          "$bin/horizon-ctl${{ matrix.exe }}" --help > /dev/null
+          "$bin/horizon-prepare${{ matrix.exe }}" --help | grep -q -- '--minecraft-dir'
+          # The version is the release's.
+          for binary in horizon-prepare horizon-server; do
+            out=$("$bin/$binary${{ matrix.exe }}" --version | tr -d '\r')
+            echo "$out"
+            [[ "$out" == "$binary $HORIZON_VERSION" ]] || { echo "::error::expected $binary $HORIZON_VERSION"; exit 1; }
+          done
+      - name: Tools from the runner
+        if: runner.environment == 'self-hosted'
+        env:
+          HORIZON_NO_SCCACHE: ${{ inputs.trusted && '1' || '' }}
+        run: bash tools/ci/runner-env.sh
+      - name: Resources prepared from the runner's own Minecraft
+        if: runner.environment == 'self-hosted'
+        run: bash tools/ci/vanilla-data.sh
+      - name: The game runs (offscreen, a new world, 1500 frames)
+        if: runner.environment == 'self-hosted'
+        run: |
+          set -euo pipefail
+          # From a scratch folder: the game keeps its saves and options in the folder it starts in.
+          home="$RUNNER_TEMP/horizon-smoke"
+          rm -rf "$home" && mkdir -p "$home"
+          version=$(sed -n 's/.*"version": *"\([^"]*\)".*/\1/p' research-lock.json | head -1)
+          client="$PWD/target/release/horizon-client"
+          resources="$PWD/.local/horizon-client/$version"
+          (cd "$home" && HORIZON_HOME="$home" HORIZON_NO_AUDIO=1 "$client" --resources "$resources" --offscreen \
+            --world smoke --seed 1 --render-distance 4 --world-frames 1500 --timeout-seconds 180 \
+            --smoke-report "$home/smoke.json" > "$home/client.log" 2>&1) || { tail -40 "$home/client.log"; exit 1; }
+          python3 - "$home/smoke.json" <<'EOF'
+          import json, sys
+          report = json.load(open(sys.argv[1]))
+          print(json.dumps(report))
+          if report.get("error") is not None or report.get("frames", 0) < 1500 or not report.get("chunks") \
+                  or not report.get("meshed_sections") or not report.get("player"):
+              sys.exit("the smoke run did not draw a world")
+          EOF
+          # Published with the release; the publish job checks it again before it publishes anything.
+          cp "$home/smoke.json" "$RUNNER_TEMP/smoke-test.json"
+      - uses: actions/upload-artifact@v4
+        if: runner.environment == 'self-hosted'
+        with:
+          name: smoke-test.json
+          path: ${{ runner.temp }}/smoke-test.json
+          if-no-files-found: error
+          retention-days: 3
+      - uses: actions/download-artifact@v4
+        with:
+          name: original-exporters
+          path: exporters
+      - name: Package
+        run: |
+          set -euo pipefail
+          cargo run --locked -p xtask -- package "target/release/horizon-client${{ matrix.exe }}" "dist/${{ matrix.dir }}"
+          cd dist
+          rm -f "${{ matrix.asset }}"
+          case "${{ matrix.asset }}" in
+            *.tar.gz) tar czf "${{ matrix.asset }}" "${{ matrix.dir }}" ;;
+            *) if [[ "$RUNNER_OS" == Windows ]]; then 7z a -tzip "${{ matrix.asset }}" "${{ matrix.dir }}" > /dev/null
+               else
+                 # Without resource forks and extended attributes: plain ditto adds an
+                 # AppleDouble `._` file beside every file that has any.
+                 ditto -c -k --norsrc --noextattr --noqtn --keepParent "${{ matrix.dir }}" "${{ matrix.asset }}"
+                 if unzip -Z1 "${{ matrix.asset }}" | grep -E '(^|/)(\._|__MACOSX/)'; then
+                   echo "::error::macOS metadata files in ${{ matrix.asset }}"; exit 1
+                 fi
+               fi ;;
+          esac
+          ls -l "${{ matrix.asset }}"
+      - name: Notarized
+        # A zip of programs can't be stapled: Gatekeeper asks Apple the first time each one runs.
+        if: runner.os == 'macOS' && vars.MACOS_SIGN_IDENTITY != '' && inputs.developer_id
+        run: |
+          for binary in horizon-client horizon-ctl horizon-prepare horizon-server; do
+            codesign --verify --strict "dist/${{ matrix.dir }}/$binary"
+          done
+          packaging/macos/notarize.sh "dist/${{ matrix.asset }}"
+      - uses: actions/upload-artifact@v4
+        with:
+          name: ${{ matrix.asset }}
+          path: dist/${{ matrix.asset }}
+          if-no-files-found: error
+          retention-days: 3
+      - name: The server build (the game without sound or controllers, as horizon-engine)
+        if: matrix.server_asset
+        run: |
+          set -euo pipefail
+          # After the client is packaged: target/release/horizon-client is rebuilt without the audio and
+          # controllers features, so it needs neither libasound nor libudev (minimal server images lack them).
+          cargo build --release --locked -p horizon-client --no-default-features --bin horizon-client
+          cargo run --locked -p xtask -- package-server target/release/horizon-client "dist/${{ matrix.server_dir }}"
+          folder="dist/${{ matrix.server_dir }}"
+          python3 tools/check_imports.py --server "$folder/horizon-engine" "$folder/horizon-server" "$folder/horizon-prepare"
+          "$folder/horizon-engine" --help | grep -q -- '--resources'
+          [[ "$("$folder/horizon-server" --version)" == "horizon-server $HORIZON_VERSION" ]]
+          cd dist
+          rm -f "${{ matrix.server_asset }}"
+          tar czf "${{ matrix.server_asset }}" "${{ matrix.server_dir }}"
+          ls -l "${{ matrix.server_asset }}"
+      - uses: actions/upload-artifact@v4
+        if: matrix.server_asset
+        with:
+          name: ${{ matrix.server_asset }}
+          path: dist/${{ matrix.server_asset }}
+          if-no-files-found: error
+          retention-days: 3
+      - name: The signing keychain, locked again
+        if: always() && runner.os == 'macOS' && vars.MACOS_SIGN_IDENTITY != '' && inputs.developer_id
+        run: packaging/macos/keychain.sh lock
+

.github/workflows/launcher.yml

@@ -192,9 +192,11 @@ jobs:
           retry "$launcher" install latest
           "$launcher" versions --installed
           "$launcher" links --json
-          clients=("$HORIZON_LAUNCHER_HOME"/versions/v*/horizon-client*)
+          # `install latest` is the Nightly since #3342 (versions/nightly-<date>-<commit>), a vX.Y.Z before.
+          clients=("$HORIZON_LAUNCHER_HOME"/versions/*/horizon-client*)
           client="${clients[0]}"
           echo "installed client: $client"
+          [[ -f "$client" ]] || { echo "::error::no game installed under versions/"; exit 1; }
           # The game's Linux build is the game's to keep portable (release.yml checks it): a
           # release linked to a Nix store is a warning here, not a broken launcher.
           soft() { if [[ "$RUNNER_OS" == "Linux" ]]; then "$@" || echo "::warning::$* failed"; else "$@"; fi; }

.github/workflows/nightly-build.yml

@@ -0,0 +1,278 @@
+name: nightly build
+run-name: nightly build${{ inputs.request && format(' (request {0})', inputs.request) || '' }}
+# The Nightly, the only build Horizon ships since 2026-10-28 (docs/release-flow.md "Nightly"; Ludovic). When the batch
+# train decides (release.yml, with the commit as `base`), once a night, and when a trusted
+# reviewer asks (`/nightly 2640 2642`, nightly-command.yml), it builds main plus the pull requests the reviewers
+# picked, merged in order (tools/ci/nightly_set.py), or main alone with none picked. Main is its newest commit where
+# checks and parity-main passed (or the `base` input), as for a release, and no Nightly is published while a
+# release-blocker is open. It publishes the result as the `nightly` pre-release, which every launcher and
+# `horizon-server update` install. The previous nightly stays a week as nightly-<date>.
+#
+# Why the signing key never meets the pull requests' code:
+# - `pick` merges the picked heads onto main with `git merge-tree --write-tree`: git objects only, no working tree,
+#   so none of their files reaches the disk and no hook, filter or script of theirs runs. It refuses any pull
+#   request that changes a path CODEOWNERS gives to Ludovic (this folder, tools/ci/, the signing and update code),
+#   pushes the merge as nightly/build-<date>-<n> and saves the set on the nightly-state branch.
+# - This file, game-build.yml and every script below run from main's copy: a schedule runs the default branch, and
+#   `uses: ./…` takes the caller's commit. A picked pull request's own .github/ is never read.
+# - `build` (game-build.yml, `trusted: false`) never reaches a release's tools: its macOS jobs run on the runner
+#   that already runs pull requests' parity jobs, never the release runner; its Rust cache has its own key and is
+#   never saved; and releases don't read the machine's shared sccache.
+# - `build` (game-build.yml) checks out and compiles the merge with no secrets: its token reads contents only and
+#   isn't kept in the checkout; the macOS programs are signed ad hoc (Developer ID needs the runner's keychain,
+#   which stays locked for nightlies).
+# - `sign` is the only job with RELEASE_SIGNING_KEY. It checks out nothing but main's tools/ci/sign_release.sh, which
+#   runs the runner's sha256sum and OpenSSL over the archives: it hashes them, never runs them. The signed message
+#   names the channel ("horizon release nightly"), so a nightly's signature can't pass for a release's.
+# - `publish` verifies the signature with main's horizon-release-sign, checks the smoke test, and only then moves
+#   the tag. Like sign, it never executes what build produced.
+# - The source ships with the build: `pick` writes horizon-source.tar.gz with `git archive` (git objects again, nothing
+#   run), `sign` signs it with the builds, and `publish` attaches it and tags the commit nightly-source/<date>-<short>
+#   for good (the dated release and the build branch go after 7 days; native mods pin the commit: docs/native-mods.md).
+#   gh workflow run "nightly build"                     # now (skips when the pick is the same commit as last night's)
+#   gh workflow run "nightly build" -f force=true       # build and publish even if unchanged
+#   gh workflow run "nightly build" -f dry_run=true     # build and sign with a throwaway key, publish nothing
+on:
+  schedule:
+    - cron: '17 20 * * *'  # 20:17 UTC: after the day's waves, before the 03:07 Paris parity audit takes the Mac mini
+  workflow_dispatch:
+    inputs:
+      force:
+        description: Build and publish even if tonight's pick is the commit already published
+        type: boolean
+        default: false
+      dry_run:
+        description: Build and sign with a throwaway key, publish nothing
+        type: boolean
+        default: false
+      issue:
+        description: The issue or pull request whose `/nightly` comment asked for this build (answered there)
+        type: string
+        default: ''
+      request:
+        description: The command's id, in the run's name so it can link the run
+        type: string
+        default: ''
+      prs:
+        description: A dry run's own set, `2640@<head> 2642@<head>` (the saved set stays)
+        type: string
+        default: ''
+      base:
+        description: The commit of main to build on (default main's newest with green checks and parity-main)
+        type: string
+        default: ''
+      urgent:
+        description: Past the day's cap of 12 builds (the train, for a release-now pull request or a forced run)
+        type: boolean
+        default: false
+permissions:
+  contents: read
+concurrency:
+  # One build at a time. A newer request replaces one still waiting: it builds the set as it is by then, so no pick
+  # is lost.
+  group: nightly-build
+  cancel-in-progress: false
+jobs:
+  pick:
+    runs-on: ubuntu-latest
+    timeout-minutes: 10
+    permissions:
+      contents: write       # nightly/build-<date>-<n> and the nightly-state branch (main is protected)
+      issues: write         # says in the thread when the picked pull requests conflict
+      pull-requests: write
+      actions: read         # main's newest green checks and parity-main runs (the base)
+    outputs:
+      build: ${{ steps.pick.outputs.build }}
+      sha: ${{ steps.pick.outputs.sha }}
+      short: ${{ steps.pick.outputs.short }}
+      source: ${{ steps.pick.outputs.source }}
+      date: ${{ steps.pick.outputs.date }}
+      version: ${{ steps.pick.outputs.version }}
+      nightly: ${{ steps.pick.outputs.nightly }}
+      source_tag: ${{ steps.pick.outputs.source_tag }}
+      dry_run: ${{ steps.mode.outputs.dry_run }}
+    steps:
+      - uses: actions/checkout@v4
+        with:
+          fetch-depth: 0
+          persist-credentials: false
+      - id: mode
+        # A dry run never publishes; a hand-started run off main is always one.
+        run: echo "dry_run=${{ github.event_name == 'workflow_dispatch' && (inputs.dry_run || github.ref != 'refs/heads/main') }}" >> "$GITHUB_OUTPUT"
+      - id: pick
+        env:
+          GH_TOKEN: ${{ github.token }}
+          FORCE: ${{ (inputs.force || steps.mode.outputs.dry_run == 'true') && 'yes' || '' }}
+          DRY_RUN: ${{ steps.mode.outputs.dry_run }}
+          NIGHTLY_ISSUE: ${{ inputs.issue }}
+          NIGHTLY_PRS: ${{ inputs.prs }}
+          NIGHTLY_BASE: ${{ inputs.base }}
+          NIGHTLY_URGENT: ${{ inputs.urgent }}
+        run: |
+          python3 tools/ci/nightly.py pick ${FORCE:+--force} | tee -a "$GITHUB_STEP_SUMMARY"
+          { echo; cat nightly-notes.md; } >> "$GITHUB_STEP_SUMMARY"
+      - name: Old nightly/build-* branches deleted (scheduled runs only)
+        # Ludovic, 2026-10-27: older than 7 days, but never the newest build or one a published nightly points to;
+        # nothing but nightly/build-* (nightly.py stale_builds, tests/test_nightly.py).
+        if: github.event_name == 'schedule'
+        env:
+          GH_TOKEN: ${{ github.token }}
+        run: |
+          { echo "### nightly/build-* branches"; python3 tools/ci/nightly.py prune-builds --days 7; } | tee -a "$GITHUB_STEP_SUMMARY"
+      - name: The source of the build (horizon-source.tar.gz)
+        if: steps.pick.outputs.build == 'true'
+        env:
+          SHA: ${{ steps.pick.outputs.sha }}
+        run: git archive --format=tar.gz --prefix="horizon-${SHA:0:7}/" -o horizon-source.tar.gz "$SHA"
+      - uses: actions/upload-artifact@v4
+        if: steps.pick.outputs.build == 'true'
+        with:
+          name: horizon-source
+          path: horizon-source.tar.gz
+          if-no-files-found: error
+          retention-days: 3
+      - uses: actions/upload-artifact@v4
+        with:
+          name: nightly-notes
+          path: nightly-notes.md
+          retention-days: 3
+
+  build:
+    needs: pick
+    if: needs.pick.outputs.build == 'true'
+    uses: ./.github/workflows/game-build.yml
+    with:
+      ref: ${{ needs.pick.outputs.sha }}
+      version: ${{ needs.pick.outputs.version }}
+      nightly: ${{ needs.pick.outputs.nightly }}
+      developer_id: false
+      trusted: false  # it can hold unreviewed pull requests: their own cache key, never saved, not the release runner
+
+  sign:
+    needs: [pick, build]
+    runs-on: ubuntu-latest
+    timeout-minutes: 10
+    # The key's only job: main's sign_release.sh hashes the archives and signs with the runner's OpenSSL.
+    environment: ${{ needs.pick.outputs.dry_run != 'true' && 'release' || '' }}
+    steps:
+      - uses: actions/checkout@v4
+        with:
+          sparse-checkout: tools/ci/sign_release.sh
+          sparse-checkout-cone-mode: false
+          persist-credentials: false
+      - uses: actions/download-artifact@v4
+        with:
+          path: dist
+          pattern: horizon-*
+          merge-multiple: true
+      - name: Sign the checksums (SHA256SUMS, SHA256SUMS.sig) for the nightly channel
+        env:
+          RELEASE_SIGNING_KEY: ${{ secrets.RELEASE_SIGNING_KEY }}
+          RELEASE_SIGNING_KEY_NEXT: ${{ secrets.RELEASE_SIGNING_KEY_NEXT }}
+          EPHEMERAL: ${{ needs.pick.outputs.dry_run == 'true' && 'yes' || '' }}
+        run: |
+          bash tools/ci/sign_release.sh nightly dist/horizon-linux-x86_64.tar.gz dist/horizon-windows-x64.zip \
+            dist/horizon-macos-arm64.zip dist/horizon-server-linux-x86_64.tar.gz dist/horizon-source.tar.gz
+      - uses: actions/upload-artifact@v4
+        with:
+          name: signature
+          path: dist/SHA256SUMS*
+          if-no-files-found: error
+          retention-days: 3
+      - uses: actions/upload-artifact@v4
+        if: needs.pick.outputs.dry_run == 'true'
+        with:
+          name: ephemeral.pub
+          path: dist/ephemeral.pub
+          retention-days: 3
+
+  publish:
+    needs: [pick, build, sign]
+    runs-on: ubuntu-latest
+    timeout-minutes: 15
+    permissions:
+      contents: write
+      issues: read          # the open release-blocker issues (gate)
+    steps:
+      - uses: actions/checkout@v4
+        with:
+          persist-credentials: false
+      - uses: actions/download-artifact@v4
+        with:
+          path: dist
+          merge-multiple: true
+      - name: The signature, checked as launchers check it
+        env:
+          EPHEMERAL: ${{ needs.pick.outputs.dry_run == 'true' && 'yes' || '' }}
+        run: |
+          key=(); [[ -n "$EPHEMERAL" ]] && key=(--key "$(cat dist/ephemeral.pub)")
+          cargo run --locked --quiet -p horizon-release-sign -- verify --tag nightly --publishing "${key[@]}" dist
+      - name: Ready to publish (the smoke test drew a world, no release-blocker is open)
+        # Right before publishing, as for a release: an issue labelled while the builds ran still holds it. A dry run
+        # only reports what a real run would do (that is how a blocker's fix is tried).
+        env:
+          GH_TOKEN: ${{ github.token }}
+          DRY_RUN: ${{ needs.pick.outputs.dry_run }}
+        run: |
+          if ! python3 tools/release_train.py gate --kind game --smoke dist/smoke-test.json --blockers; then
+            [[ "$DRY_RUN" == true ]] || { echo "::error::Nothing published"; exit 1; }
+            echo "::warning::A real run would publish nothing"
+          fi
+      - name: Publish as the `nightly` pre-release
+        if: needs.pick.outputs.dry_run != 'true'
+        env:
+          GH_TOKEN: ${{ github.token }}
+          SHA: ${{ needs.pick.outputs.sha }}
+          DATE: ${{ needs.pick.outputs.date }}
+          SOURCE_TAG: ${{ needs.pick.outputs.source_tag }}
+        run: |
+          set -euo pipefail
+          python3 tools/ci/nightly.py rotate
+          signature=(); [[ -f dist/SHA256SUMS.sig ]] && signature=(dist/SHA256SUMS.sig)
+          # A pre-release, never GitHub's latest: the latest stays the last vX.Y.Z, which launchers and servers from
+          # before the Nightly-only switch keep (they don't read Nightlies).
+          gh release create nightly --prerelease --latest=false --target "$SHA" \
+            --title "Nightly $DATE · ${SHA:0:7}" --notes-file dist/nightly-notes.md \
+            "dist/horizon-linux-x86_64.tar.gz#Nightly game files: Linux (horizon-linux-x86_64.tar.gz)" \
+            "dist/horizon-windows-x64.zip#Nightly game files: Windows (horizon-windows-x64.zip)" \
+            "dist/horizon-macos-arm64.zip#Nightly game files: macOS (horizon-macos-arm64.zip)" \
+            "dist/horizon-server-linux-x86_64.tar.gz#Nightly dedicated server for Linux (horizon-server-linux-x86_64.tar.gz)" \
+            "dist/horizon-source.tar.gz#Source of this Nightly, commit ${SHA:0:7} (horizon-source.tar.gz; kept for good as the tag $SOURCE_TAG)" \
+            dist/SHA256SUMS "${signature[@]}" dist/smoke-test.json
+          python3 tools/ci/nightly.py keep-source "$SHA" "$DATE"
+          python3 tools/ci/nightly.py prune --days 7
+      - name: Dry run, the nightly that would be published
+        if: needs.pick.outputs.dry_run == 'true'
+        run: |
+          echo "Would publish nightly at ${{ needs.pick.outputs.sha }} (${{ needs.pick.outputs.source }})"
+          ls -l dist
+
+  answer:
+    # Tells the thread that asked for this build how it ended. A conflict `pick` already explained there.
+    needs: [pick, build, sign, publish]
+    if: always() && inputs.issue != '' && needs.pick.result == 'success'
+    runs-on: ubuntu-latest
+    timeout-minutes: 5
+    permissions:
+      issues: write
+      pull-requests: write
+    steps:
+      - env:
+          GH_TOKEN: ${{ github.token }}
+          ISSUE: ${{ inputs.issue }}
+          BUILD: ${{ needs.pick.outputs.build }}
+          PUBLISHED: ${{ needs.publish.result }}
+          DRY_RUN: ${{ needs.pick.outputs.dry_run }}
+          NAME: Nightly ${{ needs.pick.outputs.date }} · ${{ needs.pick.outputs.short }}
+          RUN: ${{ github.server_url }}/${{ github.repository }}/actions/runs/${{ github.run_id }}
+        run: |
+          if [[ "$BUILD" != true ]]; then
+            text="nothing new: the published Nightly is already this build."
+          elif [[ "$PUBLISHED" == success && "$DRY_RUN" == true ]]; then
+            text="the dry run built and signed $NAME; nothing was published. $RUN"
+          elif [[ "$PUBLISHED" == success ]]; then
+            text="published $NAME: https://github.com/$GITHUB_REPOSITORY/releases/tag/nightly. Launchers install it at their next check."
+          else
+            text="the build failed, nothing was published: $RUN"
+          fi
+          gh api "repos/$GITHUB_REPOSITORY/issues/$ISSUE/comments" -f body="🤖 Nightly: $text"

.github/workflows/nightly-command.yml

@@ -0,0 +1,46 @@
+name: nightly command
+# `/nightly …` comments: the trusted reviewers in .github/trusted-reviewers.txt (and Ludovic) pick the pull requests
+# the Nightly holds (docs/release-flow.md "Nightly channel", tools/ci/nightly_set.py). This job only checks who asked,
+# saves the set on the nightly-state branch, starts `nightly build` and answers in the thread.
+#
+# Why no pull request's code runs here, though the token can write:
+# - `issue_comment` always runs this file from main, whoever comments and wherever; a pull request's own copy of it
+#   is never read.
+# - It checks out main and runs main's nightly_set.py. The comment's text and author reach it as env vars, never in
+#   a shell line.
+# - It never checks out, fetches or merges a pull request: it reads their file lists through the API. The merge
+#   happens in nightly-build.yml's `pick`, with git objects only; their code runs in its `build`, without secrets.
+on:
+  issue_comment:
+    types: [created]
+permissions:
+  contents: read
+jobs:
+  command:
+    # Every other comment skips here, before a runner starts.
+    if: startsWith(github.event.comment.body, '/nightly') && github.event.comment.user.type != 'Bot'
+    runs-on: ubuntu-latest
+    timeout-minutes: 5
+    permissions:
+      contents: write       # the nightly-state branch (main is protected)
+      actions: write        # starts `nightly build`
+      issues: write         # answers in the thread
+      pull-requests: write
+    steps:
+      - uses: actions/checkout@v4
+        with:
+          ref: main
+          persist-credentials: false
+          sparse-checkout: |
+            .github/CODEOWNERS
+            .github/trusted-reviewers.txt
+            tools/ci/nightly_set.py
+          sparse-checkout-cone-mode: false
+      - name: Run the command
+        env:
+          GH_TOKEN: ${{ github.token }}
+          BODY: ${{ github.event.comment.body }}
+          AUTHOR: ${{ github.event.comment.user.login }}
+          ISSUE: ${{ github.event.issue.number }}
+          COMMENT_URL: ${{ github.event.comment.html_url }}
+        run: python3 tools/ci/nightly_set.py command

.github/workflows/overlap-note.yml

@@ -0,0 +1,41 @@
+name: overlap note
+# One comment on a pull request naming the other open pull requests that close the same issue or change the same
+# functions, edited on every push (tools/ci/overlap_note.py, issue #3859).
+#
+# Why no pull request's code runs here, though `pull_request_target` gives a token that can write:
+# - `pull_request_target` runs this file and the script from main, never the pull request's copy.
+# - The checkout is main's (`ref: main`), blobless, with the script alone on disk. The pull requests' heads are fetched
+#   as git objects and only diffed, never checked out; git runs with hooks, fsmonitor, external diff and textconv off.
+# - The rest comes from the API. The token writes the comment only.
+on:
+  pull_request_target:
+    types: [opened, reopened, synchronize, ready_for_review]
+permissions:
+  contents: read
+jobs:
+  note:
+    if: github.event.pull_request.base.ref == 'main'
+    # A newer push replaces the note being computed.
+    concurrency:
+      group: overlap-note-${{ github.event.pull_request.number }}
+      cancel-in-progress: true
+    runs-on: ubuntu-latest
+    timeout-minutes: 10
+    permissions:
+      contents: read
+      pull-requests: write
+    steps:
+      - uses: actions/checkout@v4
+        with:
+          ref: main
+          fetch-depth: 0
+          filter: blob:none
+          persist-credentials: false
+          sparse-checkout: |
+            tools/ci/overlap_note.py
+          sparse-checkout-cone-mode: false
+      - name: Note
+        env:
+          GH_TOKEN: ${{ github.token }}
+          REPO: ${{ github.repository }}
+        run: python3 tools/ci/overlap_note.py event

.github/workflows/parity-main.yml

@@ -25,8 +25,8 @@ jobs:
   parity-main:
     # A Mac mini runner of its own (ludovics-mac-mini-2 holds only this label since 2026-10-26): behind PR parity jobs
     # this run waited 2 h while every merge replaced the pending one, and on the release runner a release then waited
-    # behind the next run. PR parity jobs have ludovics-mac-mini and the desktop. Not the desktop: a job slowed down
-    # because the maintainer came back could time out, and a failure here bisects and comments on merges.
+    # behind the next run. PR parity jobs have ludovics-mac-mini and playhorizon. Not playhorizon: its 4 CPUs
+    # make a core-crate run several times longer, and a failure here bisects and comments on merges.
     runs-on: [self-hosted, macOS, horizon-parity-main]
     timeout-minutes: 240  # a core-crate batch reruns ~300 harnesses (~60-90 min), a bisect a few rounds of the failures
     steps:

.github/workflows/parity.yml

@@ -1,6 +1,6 @@
 name: parity
-# The vanilla harnesses a pull request's changes can affect, on the Mac mini's runner, which holds the maintainer's
-# own Minecraft files (Horizon never downloads the game). Called by ci.yml for pull requests from this repository
+# The vanilla harnesses a pull request's changes can affect, on the Mac mini's runner or playhorizon's, which hold the
+# maintainer's own Minecraft files (Horizon never downloads the game). Called by ci.yml for pull requests from this repository
 # and by run-parity.yml when a maintainer labels a fork's pull request run-parity. See docs/release-flow.md.
 on:
   workflow_call:
@@ -13,6 +13,13 @@ on:
         description: The commit to check out and test
         type: string
         required: true
+      full:
+        description: >-
+          The pull request carries the full-parity label (a change every harness reaches, such as a crate split): it
+          runs on playhorizon's runner only, so the Mac mini's runners stay free for the others. While that runner is
+          busy the job waits for it.
+        type: boolean
+        default: false
 permissions:
   contents: read
 env:
@@ -21,40 +28,53 @@ env:
 
 jobs:
   parity:
-    runs-on: [self-hosted, horizon-game]
-    timeout-minutes: 120  # a change to core crates reruns ~300 harnesses: ~60-90 min on the Mac mini
+    runs-on: ${{ inputs.full && fromJSON('["self-hosted", "horizon-game", "playhorizon"]') || fromJSON('["self-hosted", "horizon-game"]') }}
+    # A change to core crates reruns ~350 harnesses: ~60-90 min on the Mac mini; on playhorizon (4 of its 8 vCPUs, 4
+    # harnesses at a time) up to a few hours, and any pull request's job may land there.
+    timeout-minutes: ${{ inputs.full && 360 || 180 }}
     steps:
       - uses: actions/checkout@v4
         with:
-          # The commit the event names: a fork's later pushes need another run-parity label.
+          # The commit the event names: a fork's later pushes need another run-parity label. The next step merges
+          # main into it.
           ref: ${{ inputs.head }}
           fetch-depth: 0
           persist-credentials: false
           # Keeps .local/ (parity state, probe builds, oracle results) and target/ between runs.
           clean: false
+      - name: The head merged into main (what merging it would land)
+        id: merge
+        env:
+          BASE_SHA: ${{ inputs.base }}
+          HEAD_SHA: ${{ inputs.head }}
+        run: |
+          # Harness fixes and game fixes that reached main since the branch was made then apply here too: a head
+          # tested alone failed harnesses already fixed on main (server_knockback before #2114, mob_ai's heap before
+          # #2270, save_roundtrip before #2212). Selection then compares with this main, so it sees only the pull
+          # request's own changes. A head that conflicts with main is tested alone.
+          set -euo pipefail
+          git merge --abort 2>/dev/null || true
+          git fetch -q --no-tags origin +refs/heads/main:refs/remotes/origin/main
+          main=$(git rev-parse origin/main)
+          if git -c user.name=parity -c user.email=parity@localhost merge -q --no-edit --no-ff "$main" >/dev/null 2>&1; then
+            echo "base=$main" >> "$GITHUB_OUTPUT"
+            echo "Tested: head ${HEAD_SHA:0:9} merged into main ${main:0:9}" | tee -a "$GITHUB_STEP_SUMMARY"
+          else
+            git merge --abort
+            echo "base=$BASE_SHA" >> "$GITHUB_OUTPUT"
+            echo "::warning::head ${HEAD_SHA:0:9} conflicts with main ${main:0:9}: tested alone, without main's fixes"
+            echo "Tested: head ${HEAD_SHA:0:9} alone (it conflicts with main ${main:0:9})" | tee -a "$GITHUB_STEP_SUMMARY"
+          fi
       - uses: dtolnay/rust-toolchain@stable
       - name: Tools from the runner
         run: bash tools/ci/runner-env.sh
       - name: Vanilla data, and resources prepared by this preparer
-        env:
-          BASE_SHA: ${{ inputs.base }}
-        run: |
-          # main's script: one written before a fix to it left a real .local/horizon-client without sounds.json on
-          # the runner, and every later job there failed `subtitle`. A branch that changes the script runs its own.
-          set -euo pipefail
-          if git rev-parse --verify -q origin/main >/dev/null \
-            && git diff --quiet "$(git merge-base "$BASE_SHA" HEAD)" HEAD -- tools/ci/vanilla-data.sh; then
-            git show origin/main:tools/ci/vanilla-data.sh > "$RUNNER_TEMP/vanilla-data.sh"
-            bash "$RUNNER_TEMP/vanilla-data.sh"
-          else
-            bash tools/ci/vanilla-data.sh
-          fi
+        run: bash tools/ci/vanilla-data.sh
       - name: The prepared output is the one the preparer's OUTPUT_VERSION says
         env:
-          BASE_SHA: ${{ inputs.base }}
+          BASE_SHA: ${{ steps.merge.outputs.base }}
         run: |
-          # The job runs main's workflow on the head's files: a head made before OUTPUT_VERSION (#1947) has neither
-          # the tool nor the number, so there is nothing to check.
+          # A head made before OUTPUT_VERSION (#1947) that conflicts with main has neither the tool nor the number.
           if [ ! -f tools/prepare_output.py ] || ! grep -q OUTPUT_VERSION crates/horizon-prepare/src/lib.rs; then
             echo "This head's preparer has no OUTPUT_VERSION: nothing to check"
             exit 0
@@ -65,47 +85,8 @@ jobs:
       - name: The harnesses this change can affect
         env:
           PARITY_HOSTS: ''
-          BASE_SHA: ${{ inputs.base }}
-        run: |
-          # main's selection (tools/parity.py --changed --list with main's parity.py and parity_reach.py), so a
-          # branch made before a better selection landed gets it too; the head's own runner then runs those
-          # harnesses. A branch that changes the selection itself selects with its own code.
-          set -euo pipefail
-          own() { python3 tools/parity.py --changed "$BASE_SHA" --timeout 2400; }  # world_spawn takes ~1480 s on a busy runner
-          fork_point=$(git merge-base "$BASE_SHA" HEAD)
-          if ! git rev-parse --verify -q origin/main >/dev/null || ! git diff --quiet "$fork_point" HEAD -- tools/parity.py tools/parity_reach.py; then
-            own
-            exit
-          fi
-          had_reach=$(git ls-files tools/parity_reach.py)
-          git show origin/main:tools/parity.py > tools/parity.py
-          git show origin/main:tools/parity_reach.py > tools/parity_reach.py
-          status=0
-          python3 tools/parity.py --changed "$BASE_SHA" --list > .local/parity-selection.txt || status=$?
-          git checkout -- tools/parity.py
-          if [ -n "$had_reach" ]; then git checkout -- tools/parity_reach.py; else rm -f tools/parity_reach.py; fi
-          cat .local/parity-selection.txt
-          if [ "$status" != 0 ]; then
-            echo "main's selection failed: the head's own selection runs"
-            own
-            exit
-          fi
-          names=$(sed '$d' .local/parity-selection.txt | grep -E '^[A-Za-z0-9_#]+$' || true)
-          # The summary line says how many would run: a count that doesn't match the names read (a format change)
-          # must not let the job pass untested.
-          expected=$(tail -1 .local/parity-selection.txt | sed -nE 's/^([0-9]+) of [0-9]+ harnesses would run$/\1/p')
-          count=$(printf '%s' "$names" | grep -c . || true)
-          if [ -z "$expected" ] || [ "$expected" != "$count" ]; then
-            echo "main's selection listed $count names, its summary says '${expected:-?}': the head's own selection runs"
-            own
-            exit
-          fi
-          if [ "$count" = 0 ]; then
-            echo "Nothing to run."
-            exit 0
-          fi
-          # shellcheck disable=SC2086
-          python3 tools/parity.py $names --timeout 2400
+          BASE_SHA: ${{ steps.merge.outputs.base }}
+        run: python3 tools/parity.py --changed "$BASE_SHA" --timeout 2400  # world_spawn takes ~1480 s on a busy runner
       - name: Logs of the failed harnesses
         if: failure()
         uses: actions/upload-artifact@v4

.github/workflows/pr-labels.yml

@@ -0,0 +1,36 @@
+name: pr labels
+# A pull request's kind label (the box ticked in the template) and area labels (the paths it changes):
+# tools/ci/pr_labels.py, CONTRIBUTING.md "Pull requests".
+#
+# Why no pull request's code runs here, though `pull_request_target` gives a token that can write to fork PRs:
+# - `pull_request_target` runs this file and the script from main, never the pull request's copy.
+# - It checks out main's script only (`ref: main`), never the pull request's head or merge commit.
+# - The script reads the event file (the description is data in JSON, never in a shell line) and the API's list of
+#   changed file names; it runs, builds and imports nothing of theirs. The token writes labels only.
+on:
+  pull_request_target:
+    types: [opened, reopened, synchronize, edited, ready_for_review]
+permissions:
+  contents: read
+jobs:
+  label:
+    # Title-only edits change nothing: skip them before a runner starts.
+    if: github.event.action != 'edited' || github.event.changes.body != null
+    runs-on: ubuntu-latest
+    timeout-minutes: 5
+    permissions:
+      contents: read
+      pull-requests: write
+    steps:
+      - uses: actions/checkout@v4
+        with:
+          ref: main
+          persist-credentials: false
+          sparse-checkout: |
+            tools/ci/pr_labels.py
+          sparse-checkout-cone-mode: false
+      - name: Label
+        env:
+          GH_TOKEN: ${{ github.token }}
+          REPO: ${{ github.repository }}
+        run: python3 tools/ci/pr_labels.py event

.github/workflows/release.yml

@@ -1,22 +1,15 @@
 name: release
-# Automatic game releases (docs/release-flow.md). After every green `checks` run on main, every 10 minutes (so a
-# release waiting for merges to settle goes out without another merge) and by hand, tools/release_train.py decides,
-# for a commit whose checks and parity-main (the vanilla harnesses on main) both passed:
-# a release when 5 pull requests merged since the last one changed what players run and the newest merged 5 minutes
-# ago, or when the oldest has waited 6 hours, or at once for a pull request labelled release-now.
-# RELEASES_PAUSED=1 (repository variable) stops them; so does an open issue labelled release-blocker, forced runs too.
-# Builds Linux (an older Ubuntu, so the binary runs on any recent distribution and on NixOS through nix-ld) and
-# Windows on GitHub, macOS on the Mac mini's runner (MAC_RUNNER=macos-latest sends it to GitHub), then
-# publishes vX.Y.Z on the release line in .github/release-line.txt (docs/versioning.md; without it, the dated
-# vYYYY.MM.DD[.N] from before 0.2) with notes from the merged pull requests, as the release and GitHub's latest: one
-# channel, which launchers, `horizon-server update` and install.sh follow at once. So it is published only after the
-# checks that used to gate a promotion pass in this run: the Mac mini's smoke test drew a world, and no release-blocker
-# is open (tools/release_train.py gate); otherwise nothing is published. macOS: with the repository variable
-# MACOS_SIGN_IDENTITY set, the programs are signed with
-# Developer ID and the hardened runtime and the zip is notarized, from the runner's signing keychain
-# (packaging/macos/README.md); unset (forks), ad hoc.
-#   gh workflow run release --ref <branch>                       # dry run: builds and notes, publishes nothing
-#   gh workflow run release -f dry_run=false -f force=true       # on main: release now, whatever the rules say
+# Automatic game releases (docs/release-flow.md). Horizon ships only the Nightly since 2026-10-28 (Ludovic): this
+# workflow is the batch train that decides when a new Nightly goes out, and `nightly build` (nightly-build.yml) builds,
+# signs and publishes it. After every green `checks` run on main, every 10 minutes (so a batch waiting for merges to
+# settle goes out without another merge) and by hand, tools/release_train.py decides, for a commit whose checks and
+# parity-main (the vanilla harnesses on main) both passed: a Nightly when 5 pull requests merged since the published
+# Nightly changed what players run and the newest merged 5 minutes ago, or when the oldest has waited 6 hours, or at
+# once for a pull request labelled release-now. RELEASES_PAUSED=1 (repository variable) stops it; so does an open issue
+# labelled release-blocker, forced runs too (nightly-build.yml checks again before publishing). One Nightly build at a
+# time, at most 12 a day (release-now and force=true pass the cap). No `vX.Y.Z` game release is made any more.
+#   gh workflow run release --ref <branch>                       # dry run: decides, starts nothing
+#   gh workflow run release -f dry_run=false -f force=true       # on main: a Nightly now, whatever the rules say
 on:
   workflow_run:
     # A game release ships a commit both passed on (parity-main runs on batches: the newest commit it passed on).
@@ -28,19 +21,24 @@ on:
   workflow_dispatch:
     inputs:
       dry_run:
-        description: Build everything and write the notes, but publish nothing
+        description: Decide only; start no Nightly build
         type: boolean
         default: true
       force:
-        description: Release even without player-facing changes, before merges settle or while paused
+        description: A Nightly even without player-facing changes, before merges settle, while paused or past the day's cap
         type: boolean
         default: false
 permissions:
   contents: read
   # The open release-blocker issues (decide).
   issues: read
+  # The checks, parity-main and nightly build runs (decide).
+  actions: read
 concurrency:
-  group: game-release
+  # One release at a time. A hand-started dry run publishes nothing, so it can't race a real release: it gets a
+  # group of its own. In the shared group, a release queued behind it replaced it as the pending run and GitHub
+  # cancelled it (#2779's dry run, 2026-10-27), which happens all day while releases go out in batches.
+  group: game-release${{ github.event_name == 'workflow_dispatch' && inputs.dry_run && '-dry-run' || '' }}
   cancel-in-progress: false
 jobs:
   decide:
@@ -51,9 +49,8 @@ jobs:
     timeout-minutes: 10
     outputs:
       release: ${{ steps.decide.outputs.release }}
-      tag: ${{ steps.decide.outputs.tag }}
-      version: ${{ steps.decide.outputs.version }}
       head: ${{ steps.decide.outputs.head }}
+      urgent: ${{ steps.decide.outputs.urgent }}
       dry_run: ${{ steps.mode.outputs.dry_run }}
     steps:
       - uses: actions/checkout@v4
@@ -73,364 +70,21 @@ jobs:
         run: |
           python3 tools/release_train.py decide --kind game ${HEAD_SHA:+--head "$HEAD_SHA"} ${FORCE:+--force} | tee decision.json
           echo "### $(jq -r '.reason' decision.json)" >> "$GITHUB_STEP_SUMMARY"
-          # The version the programs are built with (docs/versioning.md): the tag without its v.
-          tag=$(jq -r '.tag' decision.json)
-          echo "version=${tag#v}" >> "$GITHUB_OUTPUT"
-          # A dry run builds whatever the decision, to test the builds.
-          if [[ "${{ steps.mode.outputs.dry_run }}" == true ]]; then echo "release=true" >> "$GITHUB_OUTPUT"; fi
 
-  exporters:
+  nightly:
+    # The Nightly is the release: nightly-build.yml builds the decided commit plus the reviewers' picks, signs it for
+    # the Nightly channel and publishes it once its smoke test passed and no release-blocker is open.
     needs: decide
-    if: needs.decide.outputs.release == 'true'
-    # This runner holds the maintainer's own pinned Minecraft jars. Only our classes leave it.
-    runs-on: ${{ vars.MAC_RUNNER || 'ludovics-mac-mini' }}
-    # Three full preparations (two isolated, one batched) besides the compile.
-    timeout-minutes: 60
-    steps:
-      - uses: actions/checkout@v4
-        with:
-          ref: ${{ needs.decide.outputs.head }}
-          persist-credentials: false
-          clean: true
-      - uses: dtolnay/rust-toolchain@stable
-      - run: bash tools/ci/runner-env.sh
-      - run: bash tools/ci/vanilla-data.sh
-      - name: Compile and validate original exporters against the pinned jars
-        shell: bash
-        run: |
-          set -euo pipefail
-          # target/ is gone after the clean checkout, and vanilla-data.sh builds the preparer only when it
-          # prepares afresh.
-          cargo build --release --locked -p horizon-prepare
-          # Compiled here, never taken from the runner's shared preparations: pull requests' parity jobs
-          # write those (vanilla-data.sh links .local/exporters to them).
-          rm -rf .local/exporters
-          bundle=$(target/release/horizon-prepare compile-exporters --root "$PWD" | tail -1)
-          mkdir -p exporters
-          cp -R "$bundle/server" "$bundle/client" "$bundle/manifest.json" exporters/
-          # Only our classes and their manifest leave this runner.
-          stray=$(find exporters -type f ! -path exporters/manifest.json \
-            ! \( -name '*.class' \( -path 'exporters/server/dev/horizonlab/parity/*' -o -path 'exporters/client/dev/horizonlab/parity/*' \) \))
-          [ -z "$stray" ] || { echo "::error::not one of our classes: $stray"; exit 1; }
-          python3 tools/check_prepare_exporters.py --binary target/release/horizon-prepare
-      - uses: actions/upload-artifact@v4
-        with:
-          name: original-exporters
-          path: exporters/
-          if-no-files-found: error
-          retention-days: 3
-
-  build:
-    needs: [decide, exporters]
-    if: needs.decide.outputs.release == 'true'
-    name: build ${{ matrix.name }}
-    strategy:
-      fail-fast: false
-      matrix:
-        include:
-          - name: linux
-            os: ubuntu-22.04
-            dir: horizon-linux-x86_64
-            asset: horizon-linux-x86_64.tar.gz
-            # The server build too: packaging/server/install.sh installs it on Linux.
-            server_dir: horizon-server-linux-x86_64
-            server_asset: horizon-server-linux-x86_64.tar.gz
-          - name: windows
-            os: windows-latest
-            dir: horizon-windows-x64
-            asset: horizon-windows-x64.zip
-            exe: .exe
-            # The C runtime linked in, so the game runs without the Visual C++ redistributable.
-            rustflags: -C target-feature=+crt-static
-          - name: macos
-            mac: true
-            dir: horizon-macos-arm64
-            asset: horizon-macos-arm64.zip
-    runs-on: ${{ matrix.mac && (vars.MAC_RUNNER || 'ludovics-mac-mini') || matrix.os }}
-    # Notarizing the zip can take a few minutes.
-    timeout-minutes: ${{ matrix.mac && 60 || 40 }}
-    env:
-      RUSTFLAGS: ${{ matrix.rustflags }}
-      # The release's version, built in (horizon_core::release): --version, user agents, crash reports and
-      # telemetry say it. No version-bump commits.
-      HORIZON_VERSION: ${{ needs.decide.outputs.version }}
-    defaults:
-      run:
-        shell: bash
-    steps:
-      - uses: actions/checkout@v4
-        with:
-          ref: ${{ needs.decide.outputs.head }}
-          persist-credentials: false
-          # Always from a clean checkout, the Mac mini's runner too: its work folder is shared with pull requests'
-          # parity jobs, and nothing they leave (target/, an untracked .cargo/config.toml, a build script's output)
-          # may end up in a release. target/ is rebuilt from scratch; .local/ is relinked by vanilla-data.sh, which
-          # keeps its preparations outside the checkout.
-          clean: true
-      - uses: dtolnay/rust-toolchain@stable
-      - uses: Swatinem/rust-cache@v2
-        if: runner.environment == 'github-hosted'
-        with:
-          shared-key: release-${{ matrix.name }}
-      - name: ALSA and udev headers
-        if: runner.os == 'Linux'
-        run: sudo apt-get update && sudo apt-get install -y --no-install-recommends libasound2-dev libudev-dev
-      - name: Build the client, horizon-ctl, horizon-prepare and horizon-server
-        # `horizon-client/mods`: every released game runs code mods (the feature is off in dev builds).
-        run: cargo build --release --locked --features horizon-client/mods -p horizon-client --bin horizon-client --bin horizon-ctl -p horizon-prepare --bin horizon-prepare -p horizon-server --bin horizon-server
-      - name: Every program the release folder takes was built
-        run: |
-          for binary in horizon-client horizon-ctl horizon-prepare horizon-server; do
-            test -f "target/release/$binary${{ matrix.exe }}" || { echo "::error::target/release/$binary${{ matrix.exe }} is missing"; exit 1; }
-          done
-      - name: The signing keychain, unlocked
-        if: runner.os == 'macOS' && vars.MACOS_SIGN_IDENTITY != ''
-        env:
-          MACOS_SIGN_IDENTITY: ${{ vars.MACOS_SIGN_IDENTITY }}
-        run: packaging/macos/keychain.sh unlock
-      - name: Signed with Developer ID and the hardened runtime
-        # Before the checks below, so they run the programs as players will.
-        if: runner.os == 'macOS' && vars.MACOS_SIGN_IDENTITY != ''
-        env:
-          MACOS_SIGN_IDENTITY: ${{ vars.MACOS_SIGN_IDENTITY }}
-        run: |
-          for binary in horizon-client horizon-ctl horizon-prepare horizon-server; do
-            codesign --force --options runtime --timestamp --keychain "$MACOS_SIGN_KEYCHAIN" \
-              --identifier "dev.horizon.${binary#horizon-}" --sign "$MACOS_SIGN_IDENTITY" "target/release/$binary"
-            codesign --verify --strict --verbose=2 "target/release/$binary"
-          done
-      - name: Only system libraries
-        # Windows: no non-system DLL (a "DLL not found" dialog on some players' machines). Linux: the standard
-        # loader and libraries every desktop distribution has. macOS: only the system's own libraries.
-        run: |
-          for binary in horizon-client horizon-ctl horizon-prepare horizon-server; do
-            file="target/release/$binary${{ matrix.exe }}"
-            if [[ "$RUNNER_OS" == macOS ]]; then
-              others=$(otool -L "$file" | tail -n +2 | awk '{print $1}' | grep -v -E '^(/usr/lib/|/System/Library/)' || true)
-              [[ -z "$others" ]] || { echo "::error::$binary links $others"; exit 1; }
-            else
-              ${{ runner.os == 'Windows' && 'python' || 'python3' }} tools/check_imports.py "$file"
-            fi
-          done
-      - name: Every program starts
-        run: |
-          set -euo pipefail
-          bin=target/release
-          "$bin/horizon-client${{ matrix.exe }}" --help | grep -q -- '--resources'
-          "$bin/horizon-ctl${{ matrix.exe }}" --help > /dev/null
-          "$bin/horizon-prepare${{ matrix.exe }}" --help | grep -q -- '--minecraft-dir'
-          # The version is the release's.
-          for binary in horizon-prepare horizon-server; do
-            out=$("$bin/$binary${{ matrix.exe }}" --version | tr -d '\r')
-            echo "$out"
-            [[ "$out" == "$binary $HORIZON_VERSION" ]] || { echo "::error::expected $binary $HORIZON_VERSION"; exit 1; }
-          done
-      - name: Tools from the runner
-        if: runner.environment == 'self-hosted'
-        run: bash tools/ci/runner-env.sh
-      - name: Resources prepared from the runner's own Minecraft
-        if: runner.environment == 'self-hosted'
-        run: bash tools/ci/vanilla-data.sh
-      - name: The game runs (offscreen, a new world, 1500 frames)
-        if: runner.environment == 'self-hosted'
-        run: |
-          set -euo pipefail
-          # From a scratch folder: the game keeps its saves and options in the folder it starts in.
-          home="$RUNNER_TEMP/horizon-smoke"
-          rm -rf "$home" && mkdir -p "$home"
-          version=$(sed -n 's/.*"version": *"\([^"]*\)".*/\1/p' research-lock.json | head -1)
-          client="$PWD/target/release/horizon-client"
-          resources="$PWD/.local/horizon-client/$version"
-          (cd "$home" && HORIZON_HOME="$home" HORIZON_NO_AUDIO=1 "$client" --resources "$resources" --offscreen \
-            --world smoke --seed 1 --render-distance 4 --world-frames 1500 --timeout-seconds 180 \
-            --smoke-report "$home/smoke.json" > "$home/client.log" 2>&1) || { tail -40 "$home/client.log"; exit 1; }
-          python3 - "$home/smoke.json" <<'EOF'
-          import json, sys
-          report = json.load(open(sys.argv[1]))
-          print(json.dumps(report))
-          if report.get("error") is not None or report.get("frames", 0) < 1500 or not report.get("chunks") \
-                  or not report.get("meshed_sections") or not report.get("player"):
-              sys.exit("the smoke run did not draw a world")
-          EOF
-          # Published with the release; the publish job checks it again before it publishes anything.
-          cp "$home/smoke.json" "$RUNNER_TEMP/smoke-test.json"
-      - uses: actions/upload-artifact@v4
-        if: runner.environment == 'self-hosted'
-        with:
-          name: smoke-test.json
-          path: ${{ runner.temp }}/smoke-test.json
-          if-no-files-found: error
-          retention-days: 3
-      - uses: actions/download-artifact@v4
-        with:
-          name: original-exporters
-          path: exporters
-      - name: Package
-        run: |
-          set -euo pipefail
-          cargo run --locked -p xtask -- package "target/release/horizon-client${{ matrix.exe }}" "dist/${{ matrix.dir }}"
-          cd dist
-          rm -f "${{ matrix.asset }}"
-          case "${{ matrix.asset }}" in
-            *.tar.gz) tar czf "${{ matrix.asset }}" "${{ matrix.dir }}" ;;
-            *) if [[ "$RUNNER_OS" == Windows ]]; then 7z a -tzip "${{ matrix.asset }}" "${{ matrix.dir }}" > /dev/null
-               else
-                 # Without resource forks and extended attributes: plain ditto adds an
-                 # AppleDouble `._` file beside every file that has any.
-                 ditto -c -k --norsrc --noextattr --noqtn --keepParent "${{ matrix.dir }}" "${{ matrix.asset }}"
-                 if unzip -Z1 "${{ matrix.asset }}" | grep -E '(^|/)(\._|__MACOSX/)'; then
-                   echo "::error::macOS metadata files in ${{ matrix.asset }}"; exit 1
-                 fi
-               fi ;;
-          esac
-          ls -l "${{ matrix.asset }}"
-      - name: Notarized
-        # A zip of programs can't be stapled: Gatekeeper asks Apple the first time each one runs.
-        if: runner.os == 'macOS' && vars.MACOS_SIGN_IDENTITY != ''
-        run: |
-          for binary in horizon-client horizon-ctl horizon-prepare horizon-server; do
-            codesign --verify --strict "dist/${{ matrix.dir }}/$binary"
-          done
-          packaging/macos/notarize.sh "dist/${{ matrix.asset }}"
-      - uses: actions/upload-artifact@v4
-        with:
-          name: ${{ matrix.asset }}
-          path: dist/${{ matrix.asset }}
-          if-no-files-found: error
-          retention-days: 3
-      - name: The server build (the game without sound or controllers, as horizon-engine)
-        if: matrix.server_asset
-        run: |
-          set -euo pipefail
-          # After the client is packaged: target/release/horizon-client is rebuilt without the audio and
-          # controllers features, so it needs neither libasound nor libudev (minimal server images lack them),
-          # and with code mods like the client.
-          cargo build --release --locked -p horizon-client --no-default-features --features mods --bin horizon-client
-          cargo run --locked -p xtask -- package-server target/release/horizon-client "dist/${{ matrix.server_dir }}"
-          folder="dist/${{ matrix.server_dir }}"
-          python3 tools/check_imports.py --server "$folder/horizon-engine" "$folder/horizon-server" "$folder/horizon-prepare"
-          "$folder/horizon-engine" --help | grep -q -- '--resources'
-          [[ "$("$folder/horizon-server" --version)" == "horizon-server $HORIZON_VERSION" ]]
-          cd dist
-          rm -f "${{ matrix.server_asset }}"
-          tar czf "${{ matrix.server_asset }}" "${{ matrix.server_dir }}"
-          ls -l "${{ matrix.server_asset }}"
-      - uses: actions/upload-artifact@v4
-        if: matrix.server_asset
-        with:
-          name: ${{ matrix.server_asset }}
-          path: dist/${{ matrix.server_asset }}
-          if-no-files-found: error
-          retention-days: 3
-      - name: The signing keychain, locked again
-        if: always() && runner.os == 'macOS' && vars.MACOS_SIGN_IDENTITY != ''
-        run: packaging/macos/keychain.sh lock
-
-  sign:
-    needs: [decide, build]
+    if: needs.decide.outputs.release == 'true' && needs.decide.outputs.dry_run != 'true'
     runs-on: ubuntu-latest
-    timeout-minutes: 10
-    # The only job that holds the release signing key, a secret of the `release` environment, which only main's real
-    # releases enter (dry runs sign with a throwaway key). It runs no code from the repository but
-    # tools/ci/sign_release.sh, which calls only the runner's sha256sum and OpenSSL (docs/release-flow.md).
-    environment: ${{ needs.decide.outputs.dry_run != 'true' && 'release' || '' }}
-    steps:
-      - uses: actions/checkout@v4
-        with:
-          sparse-checkout: tools/ci/sign_release.sh
-          sparse-checkout-cone-mode: false
-          persist-credentials: false
-      - uses: actions/download-artifact@v4
-        with:
-          path: dist
-          pattern: horizon-*
-          merge-multiple: true
-      - name: Sign the checksums (SHA256SUMS, SHA256SUMS.sig)
-        env:
-          RELEASE_SIGNING_KEY: ${{ secrets.RELEASE_SIGNING_KEY }}
-          RELEASE_SIGNING_KEY_NEXT: ${{ secrets.RELEASE_SIGNING_KEY_NEXT }}
-          EPHEMERAL: ${{ needs.decide.outputs.dry_run == 'true' && 'yes' || '' }}
-          TAG: ${{ needs.decide.outputs.tag }}
-        run: |
-          bash tools/ci/sign_release.sh "$TAG" dist/horizon-linux-x86_64.tar.gz dist/horizon-windows-x64.zip \
-            dist/horizon-macos-arm64.zip dist/horizon-server-linux-x86_64.tar.gz
-      - uses: actions/upload-artifact@v4
-        with:
-          name: signature
-          path: dist/SHA256SUMS*
-          if-no-files-found: error
-          retention-days: 3
-      - uses: actions/upload-artifact@v4
-        if: needs.decide.outputs.dry_run == 'true'
-        with:
-          name: ephemeral.pub
-          path: dist/ephemeral.pub
-          retention-days: 3
-
-  publish:
-    needs: [decide, build, sign]
-    runs-on: ubuntu-latest
-    timeout-minutes: 15
+    timeout-minutes: 5
     permissions:
-      contents: write
-      issues: read
+      actions: write  # starts `nightly build`
     steps:
-      - uses: actions/checkout@v4
-        with:
-          fetch-depth: 0
-      - name: Notes
-        env:
+      - env:
           GH_TOKEN: ${{ github.token }}
+          HEAD_SHA: ${{ needs.decide.outputs.head }}
+          URGENT: ${{ needs.decide.outputs.urgent }}
         run: |
-          python3 tools/release_train.py notes --kind game --tag "${{ needs.decide.outputs.tag }}" \
-            --head "${{ needs.decide.outputs.head }}" --out notes > /dev/null
-          { echo "## $(cat notes/title.txt)"; echo; cat notes/body.md; } >> "$GITHUB_STEP_SUMMARY"
-      - uses: actions/download-artifact@v4
-        with:
-          path: dist
-          merge-multiple: true
-      - name: The signature, checked as launchers check it
-        env:
-          TAG: ${{ needs.decide.outputs.tag }}
-          EPHEMERAL: ${{ needs.decide.outputs.dry_run == 'true' && 'yes' || '' }}
-        run: |
-          key=(); [[ -n "$EPHEMERAL" ]] && key=(--key "$(cat dist/ephemeral.pub)")
-          cargo run --locked --quiet -p horizon-release-sign -- verify --tag "$TAG" --publishing "${key[@]}" dist
-      - name: Ready to publish (the smoke test passed, no release-blocker is open)
-        # Right before publishing: an issue labelled while the builds ran still holds this release. A dry run only
-        # reports what a real run would do.
-        env:
-          GH_TOKEN: ${{ github.token }}
-          DRY_RUN: ${{ needs.decide.outputs.dry_run }}
-        run: |
-          if ! python3 tools/release_train.py gate --kind game --smoke dist/smoke-test.json --blockers; then
-            [[ "$DRY_RUN" == true ]] || { echo "::error::Nothing published"; exit 1; }
-            echo "::warning::A real run would publish nothing"
-          fi
-      - name: Publish ${{ needs.decide.outputs.tag }}
-        if: needs.decide.outputs.dry_run != 'true'
-        env:
-          GH_TOKEN: ${{ github.token }}
-          TAG: ${{ needs.decide.outputs.tag }}
-        run: |
-          signature=(); [[ -f dist/SHA256SUMS.sig ]] && signature=(dist/SHA256SUMS.sig)
-          # The release and the latest at once: there is one channel (docs/release-flow.md). Each archive gets a
-          # label (file#label), which GitHub's page shows instead of the file name, so nobody takes the game's
-          # files for the download (#1647). Launchers, servers and install.sh match the name, which stays.
-          gh release create "$TAG" --target "${{ needs.decide.outputs.head }}" --title "$(cat notes/title.txt)" \
-            --notes-file notes/body.md --latest \
-            "dist/horizon-linux-x86_64.tar.gz#Game files the launcher installs: Linux (horizon-linux-x86_64.tar.gz)" \
-            "dist/horizon-windows-x64.zip#Game files the launcher installs: Windows (horizon-windows-x64.zip)" \
-            "dist/horizon-macos-arm64.zip#Game files the launcher installs: macOS (horizon-macos-arm64.zip)" \
-            "dist/horizon-server-linux-x86_64.tar.gz#Dedicated server for Linux (horizon-server-linux-x86_64.tar.gz)" \
-            dist/SHA256SUMS "${signature[@]}" dist/smoke-test.json
-      - name: Dry run, the release that would be published
-        if: needs.decide.outputs.dry_run == 'true'
-        run: |
-          echo "Would publish ${{ needs.decide.outputs.tag }} at ${{ needs.decide.outputs.head }} as the release and latest: $(cat notes/title.txt)"
-          ls -l dist
-      - uses: actions/upload-artifact@v4
-        with:
-          name: release-notes
-          path: notes/
-          retention-days: 3
+          gh workflow run nightly-build.yml --repo "$GITHUB_REPOSITORY" --ref main -f base="$HEAD_SHA" -f urgent="$URGENT"
+          echo "### Started \`nightly build\` on ${HEAD_SHA:0:9}" >> "$GITHUB_STEP_SUMMARY"

.github/workflows/run-parity.yml

@@ -5,11 +5,15 @@ name: run-parity
 # skipped `verify`, and GitHub counts a skipped required check as passed.
 on:
   pull_request:
-    types: [labeled]
+    # A push starts a run only to cancel the old head's (see concurrency): the job runs on the label alone.
+    types: [labeled, synchronize]
 permissions:
   contents: read
 concurrency:
-  group: run-parity-${{ github.event.pull_request.number }}
+  # The run-parity label and pushes share one group per pull request, so the newest run cancels the one before: a
+  # pushed pull request's run tested a head the merge would no longer land. Any other label gets a group of its own:
+  # in the shared one, adding needs-proof cancelled the parity run queued seconds before (run 40766180150).
+  group: run-parity-${{ github.event.pull_request.number }}${{ github.event.action == 'labeled' && github.event.label.name != 'run-parity' && format('-{0}', github.run_id) || '' }}
   cancel-in-progress: true
 env:
   # Test runs never reach the telemetry server: no live-count ping, no uploads (docs/telemetry.md).
@@ -22,3 +26,4 @@ jobs:
     with:
       base: ${{ github.event.pull_request.base.sha }}
       head: ${{ github.event.pull_request.head.sha }}
+      full: ${{ contains(github.event.pull_request.labels.*.name, 'full-parity') }}

.github/workflows/triage-command.yml

@@ -0,0 +1,48 @@
+name: triage command
+# `/close`, `/reopen`, `/label`, `/unlabel` comments: the trusted reviewers in .github/trusted-reviewers.txt (and
+# Ludovic) triage issues and pull requests without any repository role (docs/release-flow.md "Trusted reviewers",
+# tools/ci/triage_command.py).
+#
+# Why no pull request's code runs here, though the token can write:
+# - `issue_comment` always runs this file from main, whoever comments and wherever.
+# - It checks out main's script and list only, never a pull request; it reads threads through the API.
+# - The comment's text and author reach the script as env vars, never in a shell line. The token stays in the step.
+on:
+  issue_comment:
+    types: [created]
+permissions:
+  contents: read
+jobs:
+  command:
+    # Every other comment skips here, before a runner starts.
+    if: >-
+      github.event.comment.user.type != 'Bot' && (
+      startsWith(github.event.comment.body, '/close') ||
+      startsWith(github.event.comment.body, '/reopen') ||
+      startsWith(github.event.comment.body, '/label') ||
+      startsWith(github.event.comment.body, '/unlabel'))
+    runs-on: ubuntu-latest
+    timeout-minutes: 5
+    permissions:
+      contents: read
+      issues: write
+      pull-requests: write
+    steps:
+      - uses: actions/checkout@v4
+        with:
+          ref: main
+          persist-credentials: false
+          sparse-checkout: |
+            .github/trusted-reviewers.txt
+            tools/ci/nightly_set.py
+            tools/ci/triage_command.py
+          sparse-checkout-cone-mode: false
+      - name: Run the command
+        env:
+          GH_TOKEN: ${{ github.token }}
+          BODY: ${{ github.event.comment.body }}
+          AUTHOR: ${{ github.event.comment.user.login }}
+          ISSUE: ${{ github.event.issue.number }}
+          REPO: ${{ github.repository }}
+          COMMENT_URL: ${{ github.event.comment.html_url }}
+        run: python3 tools/ci/triage_command.py command

AGENTS.md

@@ -10,15 +10,18 @@ Feature → files → harness for the most-changed areas: [docs/architecture.md]
   `tools/check_public_tree.py` rejects them; `git config core.hooksPath .githooks` runs it on commit.
 - **Keep your runs away from real player data.** Any game or launcher you start gets fresh `mktemp -d`
   folders in `HORIZON_HOME` (the game's data), `HORIZON_LAUNCHER_HOME`, `XDG_DATA_HOME` and
-  `XDG_CONFIG_HOME`, plus `HORIZON_LAUNCHER_NO_SELF_UPDATE=1` and `HORIZON_NO_AUDIO=1`. Never write to
+  `XDG_CONFIG_HOME`, plus `HORIZON_LAUNCHER_NO_SELF_UPDATE=1` and `HORIZON_NO_AUDIO=1`, and, for the
+  launcher, `HORIZON_LAUNCHER_TRASH`, `HORIZON_LAUNCHER_CLIPBOARD` and `HORIZON_LAUNCHER_DESKTOP` pointing into the scratch home. Never write to
   `~/.local/share/{applications,horizon,horizon-launcher}` or `~/.local/bin`.
-- **Mark what an agent posts.** A PR body starts with a line naming whose agent opened it and with what.
-  Ludovic's agents write `> 🤖 Opened by Ludovic's AI agent (Claude), not by Ludovic himself.`, and a
-  contributor's agent names its own person and tool (issues: "Filed by", reviews: "Review by"). Every
-  comment starts with `🤖 Agent:`. Never write as Ludovic or as anyone else.
+- **Mark what an agent posts.** A PR body starts with a line naming the person whose agent opened it and
+  the tool: `> 🤖 Opened by <login>'s AI agent (<tool, model>), not by <login> personally.`, where `<login>`
+  is the GitHub account the PR is opened from (`gh api user --jq .login`). Issues say "Filed by", reviews
+  "Review by". Every comment starts with `🤖 Agent:`. Write only as the person you work for: the lines on
+  this page that name Ludovic are for his own agents (account `ludovic111`), never for anyone else's.
 - **Attribution.** Commits end with a `Co-Authored-By:` line for the agent that wrote them, and PR bodies
-  with that agent's own "Generated with" line. Ludovic's agents use
-  `Co-Authored-By: Claude <model> <[email protected]>` and
+  with that agent's own "Generated with" line. Example, Ludovic's agents (Claude Code on `ludovic111`):
+  first line `> 🤖 Opened by Ludovic's AI agent (Claude), not by Ludovic himself.`, commits
+  `Co-Authored-By: Claude <model> <[email protected]>`, last line
   `🤖 Generated with [Claude Code](https://claude.com/claude-code)`.
 - Everything players run is Rust. Python/Java only for dev tools and harness drivers in `tools/`.
 - Horizon-only features follow [docs/design-system.md](docs/design-system.md) and are off by default where
@@ -27,6 +30,8 @@ Feature → files → harness for the most-changed areas: [docs/architecture.md]
   change), none for a fix. Agents never add `release-now`: the maintainer decides it. Merges ship in batches of 5, or after
   6 hours ([docs/release-flow.md](docs/release-flow.md)).
 - Contributors first: `gh pr list --state open --search <area>` before you start; never duplicate theirs.
+- **Claim before you start**: comment `/claim` on the issue (no issue yet: open one, then claim it). An assigned
+  issue is taken: pick another. `/unclaim` when you stop; a claim with no open PR linking it is released after 5 days.
 
 ## Crates
 
@@ -34,7 +39,12 @@ Game workspace (root `Cargo.toml`); `launcher/` and `crates/horizon-telemetry-se
 
 | Crate | Owns |
 |---|---|
-| `horizon-client` | The game: a lib (`src/lib.rs`, ~190 flat modules) and the bin (`src/main.rs` → `game.rs` + `game/`), plus `horizon-ctl` (`src/bin/horizon-ctl/`). Also the dedicated server (`--dedicated`) |
+| `horizon-client` | The game: a lib (`src/lib.rs`, ~100 flat modules: gameplay, networking, title screens) and the bin (`src/main.rs` → `game.rs` + `game/`), plus `horizon-ctl` (`src/bin/horizon-ctl/`). Also the dedicated server (`--dedicated`) |
+| `horizon-items` | Blocks and items below gameplay: `blocks.rs` (block facts), `items.rs`, `item_data.rs` (components), `enchant.rs`, `cooldowns.rs`, `bundle.rs`, `item_nbt.rs`. Re-exported as `horizon_client::items`... |
+| `horizon-command` | Command parsing (Brigadier): the vanilla tree, argument types, selectors, suggestions, the tree's network form. Re-exported as `horizon_client::command` |
+| `horizon-client-core` | The client lib's bottom layer: `text.rs`, `lang.rs`, `snbt.rs`, `nbt_path.rs`, `component.rs`, `scoreboard.rs`, `bossbar.rs`, `gamerules.rs`, `block_entity_nbt.rs`, registry/particle/sound tables. Re-exported under the old paths (`horizon_client::text`...) |
+| `horizon-client-input` | Key bindings and key names, toggle keys, mouse options, controller settings and glyphs, the clipboard, window options (`keybinds.rs`, `gamepad.rs`, `mouse.rs`, `window.rs`...). Re-exported under the old paths |
+| `horizon-client-render` | The client's world data, rendering and screens (chunks, meshing, light, streaming, `gfx`, HUD, menus, settings): ~80 modules that horizon-client re-exports under the same paths. Nothing in it reaches gameplay |
 | `horizon-world` | Vanilla world data with no gameplay loop: NBT, regions, chunks, `datafix/`, `worldgen/`, `level/` (server-side block behaviour, ticks, redstone), entity physics, items, effects, food, damage |
 | `horizon-core` | Simulation primitives: Java `Random`s, `jmath` (HotSpot-exact `Math`), positions, noise, density, paletted storage, `version.rs` (the pinned version) |
 | `horizon-protocol` | Network protocol 777: codecs, framing, encryption, `packets/{handshake,status,login,configuration,play}.rs`, `entity_data.rs` |
@@ -43,7 +53,7 @@ Game workspace (root `Cargo.toml`); `launcher/` and `crates/horizon-telemetry-se
 | `horizon-server` | `horizon-server`: `server.toml`, CLI, supervisor of the headless game ([docs/hosting.md](docs/hosting.md)) |
 | `horizon-server-files` | `server.properties`, eula, ops/whitelist/bans, usercache |
 | `horizon-friends`, `horizon-relay` | Play with Friends: invite codes, encrypted tunnel, the relay ([docs/play-with-friends.md](docs/play-with-friends.md)) |
-| `horizon-mods`, `horizon-mod-sdk`, `cargo-horizon-mod` | Sandboxed WebAssembly mods: runtime, SDK + WIT, `cargo horizon-mod` ([docs/mods.md](docs/mods.md)) |
+| `horizon-mods`, `cargo-horizon-mod` | Content mods (`.hmod`: manifest, content fence, no code), the registry index and `.hpack`, and `cargo horizon-mod` (`new`, `build`, `run`, `check`, `registry`) ([docs/mods.md](docs/mods.md)). Code mods are native, built by the launcher ([docs/native-mods.md](docs/native-mods.md)) |
 | `horizon-port-pack` | Porting Java modpacks ([docs/modpacks.md](docs/modpacks.md)) |
 | `horizon-shader-api` | Horizon's own WGSL shader packs ([docs/api/shaders.md](docs/api/shaders.md)): `horizon-shaders.toml`, the `.hshader` package; shared by the game, the launcher and the registry |
 | `horizon-shaders` | Shader packs (the `shaders/` folder format), rebuilt clean-room from a written spec of the format; no wgpu |
@@ -54,7 +64,7 @@ Game workspace (root `Cargo.toml`); `launcher/` and `crates/horizon-telemetry-se
 
 Other top-level folders: `tools/` (harnesses and dev scripts), `tests/` (Python unit tests: `python3 -m
 unittest discover -s tests`), `mods/horizon/src/test/java/dev/horizonlab/parity/` (Java oracles),
-`docs/`, `.github/workflows/`. The website (playhorizon.dev) is the private ludovic111/horizon-site: its build
+`docs/`, `.github/workflows/`. The website (playhorizon.dev) is the private horizon-rust/horizon-site: its build
 reads `README.md`, `launcher/links.json`, `docs/api/`, `roadmap/roadmap.json` and `crates/horizon-theme/tokens.css` from main.
 
 ## Build and test fast
@@ -63,11 +73,12 @@ reads `README.md`, `launcher/links.json`, `docs/api/`, `roadmap/roadmap.json` an
 python3 tools/pr_ready.py                  # the self-check: fmt, clippy -D warnings, touched crates' tests, harnesses; paste its block in the PR
 python3 tools/pr_ready.py --quick          # same without harnesses
 cargo test -p horizon-client --lib --bins --tests   # skips the 104 examples (pr_ready does this); `--doc` separately
+cargo test -p horizon-client --lib mod_content::tests:: -- --ignored   # the 5 slow content-root tests, #[ignore]d; pr_ready runs them when mod content, assets, blocks or items change
 cargo build --profile fast -p horizon-client        # optimized, quick to link: use it to play or run lan_e2e
 python3 tools/parity.py --changed origin/main       # the harnesses your branch can affect (CI's parity job)
 python3 tools/parity.py --changed-files paths.txt --list   # which harnesses cover these files, without running them
 python3 tools/parity.py mob_ai sculk       # named harnesses
-python3 tools/lan_e2e.py --check chest     # two real games over LAN (server-thread host); --in-frame compares the fallback
+python3 tools/lan_e2e.py --check chest     # two real games over LAN (server-thread host)
 python3 tools/agent_control_e2e.py         # horizon-ctl / MCP end to end
 ```
 
@@ -82,9 +93,6 @@ python3 tools/agent_control_e2e.py         # horizon-ctl / MCP end to end
 - What a change reruns (of 329 harnesses, measured 2026-10-23): a file of the game binary (`game.rs`, `game/`)
   ~25, a file of the client lib ~103, of `horizon-world` ~103–109, of `horizon-core` ~119. Plan for it.
 - Rust integration tests: `crates/horizon-client/tests/` (`lan_bot.rs`, `generation_saves.rs`, `streaming_meshes.rs`).
-- **macOS:** `cargo build/test --workspace` may fail to link the two wasm guest cdylibs (undefined
-  `horizon:mods/events` symbols) until #1446 lands: add `--exclude coords-hud --exclude predator-missile --exclude horizon-mods-test-guest --exclude horizon-mods-test-ui-guest`.
-  Their real check is `cargo test -p horizon-mods` (builds them for `wasm32-unknown-unknown`).
 - Linux needs `libasound2-dev libudev-dev`; `--no-default-features` drops audio and controllers (the server build).
 - Run and drive the game (starts the `horizon-client` beside `horizon-ctl`; other arguments go to the game):
   `target/fast/horizon-ctl --socket $PWD/ctl.sock launch --world W --creative --offscreen --wait --resources $PWD/.local/horizon-client/26.3`,
@@ -93,6 +101,9 @@ python3 tools/agent_control_e2e.py         # horizon-ctl / MCP end to end
 
 ## Vanilla reference
 
+- Start parity work from the port ledger, not grep: `python3 tools/port_ledger.py issue N` (or `where
+  Class.method`, `what file:line`), and `check --base origin/main` before the PR. How:
+  [.claude/skills/vanilla-parity/SKILL.md](.claude/skills/vanilla-parity/SKILL.md), [docs/port-ledger.md](docs/port-ledger.md).
 - Decompiled sources: `.local/minecraft/26.3/sources/{client,server}/` (`python3 tools/lab.py decompile`).
 - Bytecode queries (callers through lambdas, every overload):
   `python3 tools/rea_vanilla.py method net.minecraft.world.level.block.DispenserBlock dispenseFrom`
@@ -104,30 +115,31 @@ python3 tools/agent_control_e2e.py         # horizon-ctl / MCP end to end
 
 ## horizon-client: where things live
 
-`L:` = lib (`crates/horizon-client/src/`), `G:` = bin (`crates/horizon-client/src/game/`). The lib can't see
+`L:` = lib (`crates/horizon-client/src/`, or `crates/horizon-client-render/src/` for the modules that crate holds, under
+the same `horizon_client::<module>` paths), `G:` = bin (`crates/horizon-client/src/game/`). The lib can't see
 `Game`; bin code reaches the lib as `horizon_client::<module>`.
 
 | Subsystem | Files |
 |---|---|
-| Game loop, tick, frame | `game.rs`: `fn run`, `impl ApplicationHandler for Game` (`window_event`, `about_to_wait`), `fn tick`, `fn tick_world`, `fn render`; L: `clock.rs`, `window.rs`, `spans.rs` |
+| Game loop, tick, frame | `game.rs`: `fn run`, `impl ApplicationHandler for Game` (`window_event`, `about_to_wait`), `fn tick`, `fn tick_world`, `fn render`; L: `clock.rs`, `spans.rs`; `horizon-client-input/src/window.rs` |
 | Rendering | L: `gfx.rs` (`Renderer::new`, `Renderer::render`), `gfx/` (cull, occlusion, translucency, upload, timing, lod, weather, stars, end_sky), `*.wgsl`, `particles.rs`, `block_entity_render.rs`, `item_render.rs`, `fog.rs`, `clouds.rs`, `camera.rs`, `first_person.rs`; G: `render_tick.rs`, `item_draw.rs` |
 | Chunks, streaming, light | L: `streaming.rs` (worker pool: generate, light, mesh), `world.rs`, `chunk.rs`, `chunk_map.rs`, `light.rs`, `mesher.rs` + `mesher/`, `vanillagen.rs` (binds horizon-world's generator), `lod.rs` + `lod/`, `ticket_levels.rs`; G: `world_loading.rs`, `postprocess.rs`; game.rs `fn update_world` |
 | World generation | `crates/horizon-world/src/worldgen/` (`generator*.rs`, `feature_graph.rs`, `structure/`, `carver/`) |
 | Block behaviour | `crates/horizon-world/src/level/` (`mod.rs`, `tick.rs`, `hooks.rs`, `redstone.rs`, `place.rs`, `interact.rs`); game.rs `fn tick_blocks`, `fn process_level_events` |
 | Mobs | L: `mobs.rs` (types), `mobs/` (`ai.rs`, `goals.rs`, `brain.rs`, `*_brain.rs`, `nav.rs`, `path.rs`, `species.rs`, `spawning.rs`, `render.rs`, `anim.rs`); G: `creatures.rs` (ticking, spawning, mob events), one file per mob family (`dragon.rs`, `wither.rs`, `villagers.rs`, `piglins.rs`, `golems.rs`...), `natural_spawning.rs` |
 | Other entities | L: `entities.rs`, `projectiles.rs`, `arrows.rs`; G: `boats.rs`, `minecarts.rs`, `mounts.rs`, `armor_stands.rs`, `paintings.rs`, `frames.rs`, `fireworks.rs`, `tnt.rs`, `explosion.rs` |
-| Player actions | game.rs (`fn use_hand`, `fn use_item`, `fn attack`, `fn tick_mining`, `fn break_block`); G: `hand.rs`, `combat.rs`, `consume.rs`, `potions.rs`, `shield.rs`, `crossbow.rs`, `trident.rs`, `fishing.rs`; L: `motion.rs` + `motion/` (movement), `collisions.rs`, `items.rs`, `item_data.rs` |
+| Player actions | game.rs (`fn use_hand`, `fn use_item`, `fn attack`, `fn tick_mining`, `fn break_block`); G: `hand.rs`, `combat.rs`, `consume.rs`, `potions.rs`, `shield.rs`, `crossbow.rs`, `trident.rs`, `fishing.rs`; L: `motion.rs` + `motion/` (movement), `collisions.rs`; crate `horizon-items`: `items.rs`, `item_data.rs`, `enchant.rs`, `blocks.rs` |
 | Inventory and containers | L: `menu.rs` (`AbstractContainerMenu.clicked`), `container_screen.rs`, `containers.rs`, `creative.rs`, `crafting.rs`, `recipe_book*.rs`, `stations.rs`, `merchant.rs`; game.rs `fn menu_ops`, `fn click_inventory`; G: `stations.rs`, `trading.rs`, `recipe_book.rs`, `machines.rs` |
-| Commands | parse: L: `command/` (`args.rs`, `selector.rs`, `tree_*.rs`, `vanilla.rs`); run: G: `commands.rs` (dispatch) + `commands/*.rs` (`admin`, `execute`, `items`, `players`, `world_cmds`...); L: `scoreboard_cmd.rs`, `data_cmd.rs`, `nbt_path.rs`; G: `functions.rs`, `command_blocks.rs` |
+| Commands | parse: crate `horizon-command` (`args.rs`, `selector.rs`, `tree_*.rs`, `vanilla.rs`); run: G: `commands.rs` (dispatch) + `commands/*.rs` (`admin`, `execute`, `items`, `players`, `world_cmds`...); L: `scoreboard_cmd.rs`, `data_cmd.rs`; `horizon-client-core`: `nbt_path.rs`, `scoreboard.rs`; G: `functions.rs`, `command_blocks.rs` |
 | UI screens | `Screen` enum in game.rs; L: `title.rs` + `title/`, `options_ui.rs`, `multiplayer.rs`, `pack_screen.rs`, `graphics_ui.rs`, `screen_draw.rs`, `ui.rs` (widgets), `hud.rs`, `hud_layout.rs`, `hud_overlays.rs`, `chat.rs`, `tab_list.rs`; G: `startup_menu.rs`, `screens.rs` (pause, death), `options.rs`, `lan_screen.rs`, `chat.rs`, `sign_edit.rs`, `books.rs` |
 | Multiplayer client | L: `net.rs` (network thread); G: `remote.rs` (`fn handle_packet`, `fn tick_remote`), `remote_*.rs` (mob data, objects, projectiles, vehicles, stations) |
 | LAN host / server side | L: `lan/` (`conn.rs` handshake + login threads, `hub.rs` + `hub/` play state, `chunks.rs`, `entity.rs`, `tracking.rs`, `guest.rs`, `playerdata.rs`); G: `lan.rs` (`LanHost`), `lan_actions.rs` (`fn as_guest`, `fn tick_guests`), `lan_*.rs` per feature, `lan_entities.rs` (tracked entities) |
 | Integrated server | G: `integrated.rs` (the server thread), `levels.rs` (one level per dimension, `fn tick_server`), `server_travel.rs` |
 | Dedicated server | G: `dedicated.rs`, `dedicated/status.rs`; crates `horizon-server-files`, `horizon-server` |
-| Save and load | L: `save.rs` (level.dat, regions, playerdata), `entity_nbt.rs`, `block_entity_nbt.rs`, `options_file.rs`; G: `saving.rs`, `persist.rs` (entities); `crates/horizon-world/src/{region.rs,nbt.rs,datafix/}` |
-| Input | game.rs `fn window_event`, `fn key_pressed`, `fn play_mouse`; L: `keybinds.rs`, `keymapping.rs`, `key_names.rs`, `mouse.rs`, `input.rs`, `interaction_input.rs`, `gamepad.rs`, `osk.rs`, `clipboard.rs`; G: `pad.rs`, `pad_menu.rs` |
+| Save and load | L: `save.rs` (level.dat, regions, playerdata), `entity_nbt.rs`, `options_file.rs`; `horizon-client-core/src/block_entity_nbt.rs`; G: `saving.rs`, `persist.rs` (entities); `crates/horizon-world/src/{region.rs,nbt.rs,datafix/}` |
+| Input | game.rs `fn window_event`, `fn key_pressed`, `fn play_mouse`; crate `horizon-client-input` (`keybinds.rs`, `keymapping.rs`, `key_names.rs`, `mouse.rs`, `input.rs`, `interaction_input.rs`, `gamepad.rs`, `clipboard.rs`); L: `osk.rs`; G: `pad.rs`, `pad_menu.rs` |
 | Audio | L: `audio.rs` (mixer), `sound_engine.rs`, `sound_events.rs`, `music.rs`, `ambience.rs`; G: `music.rs`, `subtitle_hud.rs` |
-| Resource packs | L: `packs.rs` + `packs/`, `pack_screen.rs`, `atlas_sources.rs`, `sprites.rs`, `mipmap.rs`, `model_library.rs`, `font.rs`, `lang.rs`; crate `horizon-assets`; G: `packs.rs` |
+| Resource packs | L: `packs.rs` + `packs/`, `pack_screen.rs`, `atlas_sources.rs`, `sprites.rs`, `mipmap.rs`, `model_library.rs`, `font.rs`; `horizon-client-core/src/lang.rs`; crate `horizon-assets`; G: `packs.rs` |
 | Agent control | L: `control.rs` (socket), `bin/horizon-ctl/`; G: `control.rs`, `agent.rs`, `events.rs`, `ui_control.rs` ([docs/agent-control.md](docs/agent-control.md)) |
 | Mods | crate `horizon-mods`; G: `mods.rs`; L: `mod_content.rs`, `mod_list.rs` |
 | Horizon extras, settings | L: `extras.rs`, `graphics.rs`, `settings.rs`, `minimap.rs`; G: `extras.rs`, `tweaks.rs`, `options.rs` |
@@ -156,17 +168,18 @@ python3 tools/agent_control_e2e.py         # horizon-ctl / MCP end to end
    "Server thread" with one level per dimension; the window joins it as a client through memory (`remote`),
    exactly as a LAN guest or a dedicated server's player does. This is what players run. Open
    `[server-thread]` issues list the gaps left.
-2. **In-frame (`--in-frame`, `--no-server-thread` or `HORIZON_SERVER_THREAD=0`):** the window's `Game` ticks
-   the world itself, one level that follows the player (`fn enter_dimension`). Deterministic rule fixtures still use this path; player-facing integration uses the default server thread.
+2. **In-frame (`--in-frame`, `--no-server-thread` or `HORIZON_SERVER_THREAD=0`): DEPRECATED, never use it, it
+   will be removed soon.** The window's `Game` ticks the world itself, one level that follows the player
+   (`fn enter_dimension`). Compatibility does not matter: don't add features or fixes for it, don't write new
+   tests against it, and move code off it when you touch it. The deterministic rule fixtures still run on it
+   until they are ported.
 
-LAN guests and dedicated servers always use the server code, so a fix there serves both. Test both paths
-when you touch player-facing gameplay:
+LAN guests and dedicated servers always use the server code, so a fix there serves both. Test the server
+thread when you touch player-facing gameplay:
 
 ```sh
 cargo run --profile fast -p horizon-client -- --resources .local/horizon-client/26.3 --world T               # server thread
-cargo run --profile fast -p horizon-client -- --resources .local/horizon-client/26.3 --world T --in-frame    # in-frame
 python3 tools/lan_e2e.py --check <name>                  # host on its server thread, guest is a server client
-python3 tools/lan_e2e.py --in-frame --check <name>       # comparison (portals, levels, distance, lava need server-thread mode)
 python3 tools/parity.py dedicated_server server_entities server_player_damage
 ```
 

CONTRIBUTING.md

@@ -74,6 +74,19 @@ including examples. The dependency scope includes optional, platform, build and
 Tests run library, binary, integration and doc tests without building unrelated example executables. Shared Cargo
 configuration and toolchain changes select the whole workspace; CI also keeps its workspace-wide checks.
 
+## Claim before you start
+
+Work is tracked in GitHub issues, and an issue that is assigned is taken (so is one with the `in progress` label:
+claimed on Discord with Kira's `/claim`): pick another, or ask its holder in the thread. Before you start, comment
+**`/claim`** on the issue; you are assigned at once, no role needed. No issue for your work yet? Open one (a line is
+enough), then claim it. `/unclaim` gives it back.
+
+A claim with no open pull request linking the issue (`Fixes #123` in the description, or a draft) is released after
+5 days, with a comment: open a draft early. You can hold 5 open issues at a time. Agents claim the same way.
+
+When your pull request changes the same functions as another open one, or closes the same issue, a bot comment names
+it (edited on every push, never repeated): talk to its author in the thread before you both finish the same work.
+
 ## Pull requests
 
 - **Small.** One change per pull request, under about 500 lines of code where you can; split bigger work into
@@ -82,10 +95,17 @@ configuration and toolchain changes select the whole workspace; CI also keeps it
   can see.
 - **Tick "Allow edits by maintainers".** When something small is left (a lint, a rebase, a nit) we push the fixup
   ourselves instead of sending it back to you; only design questions come back.
-- **Labels** (we set them if you can't): `feature` when players get something new (it appears under "New" in the
-  release notes), `skip-release` when players see no change (tooling, docs, tests), nothing for a fix.
+- **Tick its kind** in the template: `parity` (Horizon now does what vanilla does), `bug` (a crash or breakage),
+  `perf`, `feature` (new for players), `extra` (Horizon-only, off by default), `tooling` or `docs`. A workflow sets
+  that label, and area labels (`launcher`, `mobs`, `worldgen`, `rendering`...) from the paths you change.
+  `label:parity` is the list of real progress toward vanilla.
+- **Release labels** (we set them if you can't): `feature` also puts it under "New" in the release notes,
+  `skip-release` when players see no change (tooling, docs, tests), nothing for a fix.
   `release-now` is for crash fixes that shouldn't wait. pr_ready suggests one.
 
+Who reviews and merges: the Horizon Team, on CI for ordinary pull requests; risky ones (saves, network, world
+generation, the launcher's updates) wait for a local proof first ([merging](docs/release-flow.md#merging)).
+
 Every merge to main is released automatically ([release flow](docs/release-flow.md)), so main always stays playable.
 How agents, checks, releases and signed updates keep this safe: [security](docs/security.md).
 
@@ -98,5 +118,5 @@ new pushes, we add it again.
 
 ## Talk to us
 
-[Discord](https://discord.gg/HcTeMZxe5E) for questions and ideas, [issues](https://github.com/ludovic111/horizon/issues)
-for bugs. If you want to take something on, say so in its issue so nobody else starts the same work.
+[Discord](https://discord.gg/HcTeMZxe5E) for questions and ideas, [issues](https://github.com/horizon-rust/horizon/issues)
+for bugs. To take something on, `/claim` its issue ([above](#claim-before-you-start)).

Cargo.toml

@@ -1,6 +1,36 @@
 [workspace]
 exclude = ["launcher", "crates/horizon-telemetry-server", "crates/horizon-mod-registry", "third_party/wgpu-hal"]
-members = ["crates/horizon-core", "crates/horizon-dualsense", "crates/horizon-threads", "crates/horizon-hdr", "crates/horizon-world", "crates/horizon-client", "crates/horizon-server-files", "crates/horizon-server", "crates/horizon-bots", "crates/horizon-assets", "crates/horizon-protocol", "crates/horizon-theme", "crates/horizon-prepare", "crates/horizon-telemetry", "crates/horizon-bench", "crates/horizon-friends", "crates/horizon-relay", "crates/horizon-mod-sdk", "crates/horizon-mods", "crates/horizon-mods/tests/guest", "crates/horizon-mods/tests/ui_guest", "crates/cargo-horizon-mod", "crates/horizon-port-pack", "crates/horizon-shaders", "crates/horizon-shader-api", "crates/horizon-release-sign", "crates/horizon-mod-sdk/examples/coords-hud", "crates/horizon-mod-sdk/examples/predator-missile", "crates/horizon-mod-sdk/examples/welcome", "mods/official/fps-overlay", "mods/official/keystrokes", "mods/official/minimap", "mods/official/zoom", "xtask"]
+members = [
+    "crates/horizon-core",
+    "crates/horizon-dualsense",
+    "crates/horizon-threads",
+    "crates/horizon-hdr",
+    "crates/horizon-world",
+    "crates/horizon-client",
+    "crates/horizon-client-core",
+    "crates/horizon-client-input",
+    "crates/horizon-client-render",
+    "crates/horizon-command",
+    "crates/horizon-items",
+    "crates/horizon-server-files",
+    "crates/horizon-server",
+    "crates/horizon-bots",
+    "crates/horizon-assets",
+    "crates/horizon-protocol",
+    "crates/horizon-theme",
+    "crates/horizon-prepare",
+    "crates/horizon-telemetry",
+    "crates/horizon-bench",
+    "crates/horizon-friends",
+    "crates/horizon-relay",
+    "crates/horizon-mods",
+    "crates/cargo-horizon-mod",
+    "crates/horizon-port-pack",
+    "crates/horizon-shaders",
+    "crates/horizon-shader-api",
+    "crates/horizon-release-sign",
+    "xtask",
+]
 resolver = "2"
 
 [workspace.package]
@@ -19,8 +49,10 @@ large_enum_variant = "allow"
 # wgpu-hal 30.0.1 with gfx-rs/wgpu#10124: wgpu 30 creates a Vulkan descriptor
 # pool with no pool sizes while it creates the device, which Vulkan allows only
 # since 1.3.215, and Intel's Windows driver for 6th-10th gen iGPUs (HD 520/530,
-# UHD 620/630) crashes on it with an access violation (#746). Drop this and the
-# folder once a wgpu release has the fix.
+# UHD 620/630) crashes on it with an access violation (#746). It also fixes the
+# Metal backend's lookup of the CoreGraphics HDR colour space names, which handed
+# CoreGraphics a symbol's address as the string and crashed HDR output on macOS.
+# Drop this and the folder once a wgpu release has both fixes.
 [patch.crates-io]
 wgpu-hal = { path = "third_party/wgpu-hal" }
 

LICENSE

@@ -1,6 +1,6 @@
 MIT License
 
-Copyright (c) 2026 Ludovic
+Copyright (c) 2026 Ludovic Marie and the Horizon contributors
 
 Permission is hereby granted, free of charge, to any person obtaining a copy
 of this software and associated documentation files (the "Software"), to deal

README.md

@@ -1,9 +1,9 @@
 <p align="center">
-  <img src="docs/media/banner.webp" alt="Horizon: Minecraft: Java Edition 26.3, rewritten in Rust and checked against vanilla by 281 differential harnesses" width="100%">
+  <img src="docs/media/banner.webp" alt="Horizon: Minecraft: Java Edition 26.3, rewritten in Rust and checked against vanilla by more than 300 differential harnesses" width="100%">
 </p>
 
 <p align="center">
-  <a href="https://github.com/ludovic111/horizon/actions/workflows/ci.yml"><img src="https://github.com/ludovic111/horizon/actions/workflows/ci.yml/badge.svg?branch=main" alt="CI"></a>
+  <a href="https://github.com/horizon-rust/horizon/actions/workflows/ci.yml"><img src="https://github.com/horizon-rust/horizon/actions/workflows/ci.yml/badge.svg?branch=main" alt="CI"></a>
   <img src="https://img.shields.io/badge/Minecraft-Java%2026.3-5D9C3F" alt="Minecraft Java 26.3">
   <img src="https://img.shields.io/badge/Rust-stable-B7410E?logo=rust&logoColor=white" alt="Rust">
   <img src="https://img.shields.io/badge/vanilla%20parity-100%25-F0795A" alt="Vanilla parity 100%">
@@ -15,7 +15,7 @@
   <a href="https://playhorizon.dev"><b>Website</b></a> ·
   <a href="#download"><b>Download</b></a> ·
   <a href="https://playhorizon.dev/docs/"><b>Documentation</b></a> ·
-  <a href="https://github.com/ludovic111/horizon/releases"><b>Release notes</b></a> ·
+  <a href="https://github.com/horizon-rust/horizon/releases"><b>Release notes</b></a> ·
   <a href="ROADMAP.md"><b>Roadmap</b></a> ·
   <a href="#project-status"><b>Project status</b></a> ·
   <a href="#contributing"><b>Contributing</b></a>
@@ -23,15 +23,15 @@
 
 # Horizon
 
-Horizon is Minecraft: Java Edition 26.3 rewritten in Rust: a native game that reads the same worlds, follows the same rules and generates the same terrain as the Java game, and is checked against it by 281 differential harnesses. You play it through a small launcher, on the files from your own copy of Minecraft. It is free, open source and unofficial.
+Horizon is Minecraft: Java Edition 26.3 rewritten in Rust: a native game that reads the same worlds, follows the same rules and generates the same terrain as the Java game, and is checked against it by more than 300 differential harnesses. You play it through a small launcher, on the files from your own copy of Minecraft. It is free, open source and unofficial.
 
 > Not an official Minecraft product. Not approved by or associated with Mojang or Microsoft. Horizon contains no Minecraft code, assets or data: you need your own legally obtained copy of Minecraft: Java Edition 26.3.
 
 ## Download
 
-Horizon is installed through **the Horizon launcher**. Get it from [playhorizon.dev](https://playhorizon.dev) (the Download button picks your system) or from [the launcher releases](https://github.com/ludovic111/horizon/releases?q=launcher-v&expanded=true), for Linux x86-64, macOS on Apple Silicon or Windows x64. The launcher installs and updates the game, prepares its files from your own copy of Minecraft, and updates itself.
+Horizon is installed through **the Horizon launcher**. Get it from [playhorizon.dev](https://playhorizon.dev) (the Download button picks your system) or from [the launcher releases](https://github.com/horizon-rust/horizon/releases?q=launcher-v&expanded=true), for Linux x86-64, macOS on Apple Silicon or Windows x64. The launcher installs the game and keeps it up to date with each new build (Horizon ships on one channel, the Nightly), prepares its files from your copy of Minecraft (your own install, or downloaded from Mojang for your account), and updates itself.
 
-**You need** Minecraft: Java Edition 26.3, played once (the official launcher, Prism, MultiMC and other launchers all work); a Java 25 runtime, for the one-time preparation; and a GPU with Vulkan on Linux and Windows, or any Apple Silicon Mac. Step by step, with macOS's first-open prompt and the first launch: [Install and first launch](https://playhorizon.dev/docs/install).
+**You need** a Microsoft account that owns Minecraft: Java Edition (the launcher signs in with it, as other launchers do; see [Microsoft account](docs/microsoft-account.md)) and a GPU with Vulkan or OpenGL 3.3 on Linux, Vulkan or DirectX 12 on Windows, or any Apple Silicon Mac. Nothing else: with no Minecraft on your computer, Play downloads 26.3 and the Java it needs from Mojang for your account, as the official launcher does, then prepares it once. An install you already have (the official launcher, Prism, MultiMC and other launchers all work) is used instead. Step by step, with macOS's first-open prompt and the first launch: [Install and first launch](https://playhorizon.dev/docs/install).
 
 <table>
   <tr>
@@ -46,9 +46,9 @@ The [documentation](https://playhorizon.dev/docs/) covers each of these.
 
 - **The game:** singleplayer with vanilla's world generation, mobs, villagers, raids, redstone, every command, the HUD and the recipe book, on saves in vanilla's format. Worlds from 1.8 to 26.2 are upgraded as vanilla does. [Status table](#project-status).
 - **Horizon's own extras:** new menus (vanilla's are one setting away), graphics presets, distant terrain up to 1024 chunks, controller support, optional zoom, minimap and more, all off by default where they would change the vanilla look. See [Settings](https://playhorizon.dev/docs/settings).
-- **Resource packs and data packs:** resource packs work, and data packs load functions, predicates and item modifiers.
-- **Playing with others:** invite friends from the pause menu's Friends button with a code, Open to LAN, and joining offline-mode servers. Horizon cannot sign in to a Microsoft account yet, so it cannot join servers that check accounts. See [Multiplayer](https://playhorizon.dev/docs/multiplayer).
-- **Mods:** Horizon has its own mod system (Rust compiled to WebAssembly). Java mod jars do not run. See [Mods and data packs](https://playhorizon.dev/docs/mods).
+- **Resource packs and data packs:** resource packs work, and data packs load functions, predicates, item modifiers and world generation (vanilla's heights and biomes for now).
+- **Playing with others:** invite friends from the pause menu's Friends button with a code, Open to LAN, and joining servers, online-mode ones with the Microsoft account the launcher signs in with. See [Multiplayer](https://playhorizon.dev/docs/multiplayer).
+- **Mods:** content mods add blocks, items and data, and native mods change the game's own Rust code, built by the launcher on your copy, with no Rust to install. Horizon's own (Zoom, FPS Counter, Keystrokes, Minimap, Recipes and Coordinates HUD) are native mods. Java mod jars do not run in Horizon. See [Mods and data packs](https://playhorizon.dev/docs/mods).
 
 Screenshots, captured in the Rust client itself with vanilla assets and no mods or shaders:
 
@@ -93,13 +93,13 @@ Commands block until the action is done and reply with what happened; errors are
 
 For developers. Requirements: Rust 1.90 or newer, Python 3.10 or newer, JDK 25, and on Linux the ALSA and udev development headers (`libasound2-dev libudev-dev` on Debian and Ubuntu). Development and the vanilla harnesses run on Linux.
 
-Horizon contains no game files and never downloads them. It builds its resources from **your own copy** of Minecraft: Java Edition 26.3, verified against the checksums in `research-lock.json`:
+Horizon contains no game files, and `horizon-prepare` never downloads them (the launcher downloads them from Mojang only for a signed-in account that owns the game). It builds its resources from **your own copy** of Minecraft: Java Edition 26.3, verified against the checksums in `research-lock.json`:
 
 1. **Client:** install Java Edition with the official launcher and play 26.3 once. Horizon reads `versions/26.3/`, `libraries/` and `assets/` from the launcher's game directory (`~/.minecraft` on Linux). If yours lives elsewhere, pass `--minecraft-dir` or set `HORIZON_MINECRAFT_DIR`.
 2. **Server jar:** the 26.3 server jar, from the `downloads.server.url` in your launcher's `versions/26.3/26.3.json` (or [minecraft.net/download/server](https://www.minecraft.net/en-us/download/server) while 26.3 is the current release). Pass it with `--server-jar` or set `HORIZON_SERVER_JAR`. It is only needed the first time.
 
 ```sh
-git clone https://github.com/ludovic111/horizon.git
+git clone https://github.com/horizon-rust/horizon.git
 cd horizon
 cargo run --release -p horizon-prepare -- --prepare --server-jar ~/Downloads/server.jar   # needs JDK 25
 cargo run --release -p horizon-prepare -- sounds   # optional: sounds from your launcher install
@@ -139,6 +139,11 @@ average; `tests/test_parity.py` keeps it in sync with this table. Last audited
 rerun whenever one of its inputs changed, and the Mac mini now runs every one of
 them too (Rust uses Java's own float maths on each platform).
 
+The harnesses measure behaviour. A second measure is method by method: the [port ledger](tools/port_ledger.py)
+lists every method of vanilla 26.3 next to the Rust functions that port it, with a verdict for each one
+(ported, folded into another function, missing, or needing no port), and the untested ports. Run
+`python3 tools/port_ledger.py build`, then `coverage`, with the vanilla data in `.local/`.
+
 | Subsystem | Score | Main gaps |
 | --- | ---: | --- |
 | Window, input and game loop | 1 | None: the game loop, options, camera, auto-jump, toggle sprint/sneak, local input and the frame limiter match vanilla |
@@ -158,7 +163,7 @@ them too (Rust uses Java's own float maths on each platform).
 
 ### Known issues
 
-Horizon can't sign in to a Microsoft account yet, so it can't join online-mode servers (it joins offline-mode ones); skins served over https show the default skin unless already cached; pack icons show the unknown-pack texture in game; the creative hotbar keys (C/X) aren't wired to the hotbar loader; item tooltips lack attribute lines.
+Skins served over https show the default skin unless already cached; pack icons show the unknown-pack texture in game; the creative hotbar keys (C/X) aren't wired to the hotbar loader; item tooltips lack attribute lines.
 
 ## Licence
 

benchmarks/perf/horizon-win-9800x3d-5080-rd16.json

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+{
+ "format": "horizon-benchmark-report",
+ "version": 1,
+ "kind": "game",
+ "created": "2026-10-29T01:13:01Z",
+ "app": {
+  "name": "horizon-client",
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+  "commit": null
+ },
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+}

benchmarks/perf/horizon-win-9800x3d-5080-rd32.json

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+{
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+ "version": 1,
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+}

benchmarks/perf/horizon-win-9800x3d-5080-rd8.json

@@ -0,0 +1,773 @@
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benchmarks/perf/vanilla-mods-win-9800x3d-5080-rd16.json

@@ -0,0 +1,706 @@
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benchmarks/perf/vanilla-mods-win-9800x3d-5080-rd32.json

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benchmarks/perf/vanilla-win-9800x3d-5080-rd8.json

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+  },
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+   "stdev": 38.925,
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+ },
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+ "label": "vanilla-win-9800x3d-5080"
+}

benchmarks/perf/windows-9800x3d-5080-2026-10-29.md

@@ -0,0 +1,106 @@
+# Horizon v0.2.97 vs vanilla 26.3 on Windows 11: Ryzen 7 9800X3D + RTX 5080 (2026-10-29, RD 8 and 32 rerun 2026-10-30)
+
+The first `tools/perf_bench.py` run on Windows ([docs/benchmark.md](../../docs/benchmark.md)): Horizon, vanilla 26.3 and
+vanilla with performance mods, render distances 8, 16 and 32, 1280x720, three games each, every game from a fresh
+world. The reports are the `*-win-9800x3d-5080-rd*.json` files next to this page.
+
+```sh
+python tools/perf_bench.py --table horizon-win-9800x3d-5080 vanilla-win-9800x3d-5080 vanilla-mods-win-9800x3d-5080
+```
+
+## Setup
+
+- **Machine:** AMD Ryzen 7 9800X3D (8 cores, 16 threads), 94 GB RAM (DDR5, EXPO off), NVIDIA GeForce RTX 5080
+  (driver 617.42), Windows 11 Pro 26200, Balanced power plan, desktop. One 1920x1080 120 Hz display. The game windows
+  were on the desktop of an unlocked session.
+- **Horizon:** release v0.2.97 as the launcher installs it (`--build %APPDATA%\horizon-launcher\versions\v0.2.97`,
+  `--resources` its `.local\horizon-client\26.3`), Vulkan.
+- **Vanilla:** the 26.3 client jar with Fabric Loader 0.19.5 and the driver mod, Java 25.0.5 (Temurin), `-Xmx2G`
+  with the launcher's G1 flags and the manifest's `-XX:StackShadowPages=32`, OpenGL 3.3.
+- **Vanilla + mods:** the same with Sodium mc26.3-0.9.2, Lithium mc26.3-0.26.2, FerriteCore 9.0.0 and
+  ImmediatelyFast 1.17.1 (`tools/benchmark-deps/mods.lock.json`).
+- **Commands:** `python tools/perf_bench.py --game <game> --label <game>-win-9800x3d-5080 --distances <d>
+  --sizes 1280x720 --repeats 3` (plus `--build` and `--resources` for Horizon), with the games taking turns at
+  each distance.
+- **Memory** is the working set on Windows (what Task Manager shows), sampled from outside the process. Horizon's
+  GPU figure is its own Vulkan allocator total. `nvidia-smi` gives no per-process figure under WDDM, so vanilla has
+  none.
+
+## Load
+
+Windows has no load average, so the reports have no `load_avg_1m`. Every game ran on an otherwise idle machine:
+
+- **RD 8 and RD 32** (rerun on 2026-10-30, after the first pass had builds running alongside): a script started each
+  game only once no `rustc`, `cargo`, `link` (or other compiler) process and no other game (`horizon-client`, `java`,
+  `javaw`, Minecraft) was running, and the machine's CPU load had stayed under 15 % in every 5-second sample for
+  30 seconds. During each game it sampled every 2 seconds the machine's CPU load and the CPU of everything outside the
+  benchmark's own processes. A game during which a compiler or another game ran, or other processes used over 15 % of
+  the machine for 10 seconds, was discarded and run again: two of the 20 games were (vanilla + mods at RD 32, a
+  build started during one, background processes during the other).
+- **RD 16** (2026-10-29): no `rustc`, `cargo` or `link` process at any point, the load logged every 5 seconds.
+
+| Game | RD | Mean / max CPU load (machine, the game included) | Other processes' CPU, mean / max | Compiler processes |
+|---|---|---|---|---|
+| Horizon | 8 | 18 % / 49 % | 6 % / 12 % | 0 |
+| Vanilla | 8 | 28 % / 75 % | 7 % / 20 % | 0 |
+| Vanilla + mods | 8 | 30 % / 81 % | 7 % / 20 % | 0 |
+| Horizon | 16 | 29 % / 80 % | – | 0 |
+| Vanilla | 16 | 41 % / 91 % | – | 0 |
+| Vanilla + mods | 16 | 51 % / 90 % | – | 0 |
+| Horizon | 32 | 36 % / 100 % | 5 % / 15 % | 0 |
+| Vanilla | 32 | 39 % / 73 % | 6 % / 18 % | 0 |
+| Vanilla + mods | 32 | 42 % / 88 % | 6 % / 21 % | 0 |
+
+"Other processes" is the machine's load minus the benchmark's own processes (the game and `perf_bench.py`), in
+2-second samples. Most of it is the system's share of the game's own drawing (the graphics driver and the
+compositor), which no process of the benchmark is charged for; the desktop apps left open (a browser, chat apps)
+briefly reached 5 % at most. RD 16's load was logged from outside every 5 seconds, so it has no such split, and its mean includes the time between
+games. Compared with the first pass, the idle RD 8 runs give Horizon about 10 % higher averages and about 50 % higher
+1% lows, and vanilla up to 10 % higher averages.
+
+## Results
+
+Mean of 3 games ± 95% confidence interval. FPS over the 12-second flight at 16 blocks/s (average / 1% low /
+0.1% low):
+
+| RD | scene | Horizon v0.2.97 | Vanilla 26.3 | Vanilla + mods |
+| --- | --- | --- | --- | --- |
+| 8 | forest | 3495 ±276 / 1295 ±397 / 859 ±298 | 2457 ±836 / 625 ±224 / 252 ±52 | 2425 ±65 / 733 ±30 / 250 ±22 |
+| 8 | mountain | 3376 ±67 / 1384 ±168 / 850 ±256 | 2605 ±811 / 700 ±218 / 264 ±71 | 2538 ±167 / 760 ±34 / 241 ±44 |
+| 8 | ocean | 3346 ±147 / 1358 ±237 / 912 ±235 | 2470 ±828 / 689 ±241 / 286 ±53 | 2432 ±82 / 764 ±37 / 262 ±37 |
+| 8 | village | 2942 ±197 / 1271 ±146 / 839 ±94 | 2217 ±112 / 545 ±37 / 215 ±14 | 2104 ±101 / 577 ±84 / 196 ±47 |
+| 16 | forest | 2424 ±138 / 709 ±165 / 401 ±100 | 1912 ±324 / 402 ±89 / 149 ±25 | 1746 ±32 / 461 ±27 / 179 ±9 |
+| 16 | mountain | 1961 ±99 / 537 ±96 / 297 ±75 | 1653 ±153 / 332 ±27 / 113 ±8 | 1500 ±55 / 408 ±40 / 140 ±10 |
+| 16 | ocean | 2201 ±183 / 554 ±251 / 325 ±326 | 1861 ±289 / 446 ±142 / 165 ±29 | 1815 ±119 / 514 ±142 / 192 ±58 |
+| 16 | village | 1712 ±192 / 593 ±80 / 358 ±69 | 1218 ±65 / 318 ±16 / 127 ±5 | 1282 ±162 / 343 ±25 / 132 ±12 |
+| 32 | forest | 1389 ±70 / 504 ±33 / 330 ±118 | 1203 ±51 / 228 ±13 / 108 ±12 | 929 ±8 / 313 ±41 / 129 ±32 |
+| 32 | mountain | 1086 ±34 / 258 ±78 / 108 ±37 | 815 ±61 / 55 ±13 / 8 ±3 | 645 ±10 / 166 ±12 / 86 ±21 |
+| 32 | ocean | 1189 ±27 / 155 ±9 / 68 ±8 | 1223 ±33 / 236 ±17 / 99 ±21 | 1017 ±14 / 325 ±38 / 117 ±28 |
+| 32 | village | 1164 ±9 / 416 ±39 / 216 ±86 | 882 ±48 / 184 ±12 / 83 ±17 | 926 ±17 / 250 ±5 / 93 ±11 |
+
+Startup, loading and memory (means of 3 games):
+
+| RD | | Horizon v0.2.97 | Vanilla 26.3 | Vanilla + mods |
+| --- | --- | --- | --- | --- |
+| 8 | start to title / in-world | 3.0 s / 6.1 s | 7.7 s / 13.9 s | 11.1 s / 17.6 s |
+| 8 | mean scene load | 1.3 s | 4.0 s | 3.6 s |
+| 8 | working set, steady / peak | 1082 / 1172 MB | 1913 / 2120 MB | 1904 / 2053 MB |
+| 16 | start to title / in-world | 3.2 s / 7.2 s | 7.7 s / 19.9 s | 10.8 s / 23.5 s |
+| 16 | mean scene load | 2.4 s | 9.2 s | 9.0 s |
+| 16 | working set, steady / peak | 1236 / 1459 MB | 2300 / 2540 MB | 2327 / 2496 MB |
+| 32 | start to title / in-world | 2.9 s / 10.5 s | 7.5 s / 35.4 s | 11.0 s / 39.2 s |
+| 32 | mean scene load | 5.7 s | 21.1 s | 19.9 s |
+| 32 | working set, steady / peak | 1730 / 2045 MB | 2799 / 2892 MB | 2895 / 2965 MB |
+
+## What it shows
+
+- At RD 8 and 16, Horizon's average FPS is 18–42 % above vanilla's in every scene. Its 1% lows are 1.2–2.3 times
+  vanilla's and its 0.1% lows 2.0–3.9 times. On this CPU and GPU the performance mods leave vanilla's averages
+  level or slightly lower, and raise its 1% lows by 6–23 %.
+- At RD 32, Horizon's average is 15–33 % above vanilla's over the forest, the mountain and the village, with 1% lows
+  2.2–4.7 times vanilla's. Over the ocean its average is level with vanilla's, but its lows are lower than vanilla's
+  and the modded client's (155 vs 236 and 325 FPS 1% low, 68 vs 99 and 117 FPS 0.1% low), on an idle machine too.
+  That scene is worth a closer look.
+- Horizon reaches the title screen 2.4–2.6 times faster than vanilla (3.4–3.8 times faster than the modded client)
+  and loads a scene's chunks 3–4 times faster. Its steady working set is 38–46 % smaller.
+- Each game uses its own graphics API: Horizon Vulkan, vanilla OpenGL. That difference is part of what's compared.

benchmarks/server-equal-mixed-2026-10-18/README.md

@@ -119,7 +119,7 @@ machines during the runs.
 
 ## Reproduce
 
-    curl -fsSL https://raw.githubusercontent.com/ludovic111/horizon/main/packaging/server/install.sh | sh
+    curl -fsSL https://raw.githubusercontent.com/horizon-rust/horizon/main/packaging/server/install.sh | sh
     horizon-prepare --prepare --server-jar /path/to/server.jar      # your own copy
     cargo build --release -p horizon-bots                            # on the machine that runs the bots
     # in a checkout whose .local/minecraft holds the pinned vanilla jars (tools/lab.py prepare):

benchmarks/server-four-way-2026-10-19/README.md

@@ -148,7 +148,7 @@ early, wrote no report. Its lines come from its output.
 
 ## Reproduce
 
-    curl -fsSL https://raw.githubusercontent.com/ludovic111/horizon/main/packaging/server/install.sh | sh
+    curl -fsSL https://raw.githubusercontent.com/horizon-rust/horizon/main/packaging/server/install.sh | sh
     horizon-prepare --prepare --server-jar /path/to/server.jar      # your own copy
     cargo build --release -p horizon-bots                            # on the machine that runs the bots
     # in a checkout whose .local/minecraft holds the pinned vanilla jars (tools/lab.py prepare):

benchmarks/server-mixed-2026-10-18/README.md

@@ -103,7 +103,7 @@ the Nix store, so the run set `LD_LIBRARY_PATH` to them (see #898).
 
 ## Reproduce
 
-    curl -fsSL https://raw.githubusercontent.com/ludovic111/horizon/main/packaging/server/install.sh | sh
+    curl -fsSL https://raw.githubusercontent.com/horizon-rust/horizon/main/packaging/server/install.sh | sh
     horizon-prepare --prepare --server-jar /path/to/server.jar      # your own copy
     cargo build --release -p horizon-bots                            # on the machine that runs the bots
     # in a checkout whose .local/minecraft holds the pinned vanilla jars (tools/lab.py prepare):

crates/cargo-horizon-mod/Cargo.toml

@@ -4,10 +4,10 @@ version = "0.1.0"
 edition.workspace = true
 license.workspace = true
 rust-version = "1.86"
-description = "cargo horizon-mod new/build/run/check: make Horizon mods in Rust (docs/mods.md)"
+description = "cargo horizon-mod new/build/run/check: make Horizon content mods (docs/mods.md)"
 
 [dependencies]
-horizon-mods = { path = "../horizon-mods", default-features = false, features = ["pack", "runtime", "index"] }
+horizon-mods = { path = "../horizon-mods", default-features = false, features = ["index"] }
 serde_json = "1.0.151"
 
 [lints]

crates/cargo-horizon-mod/src/check.rs

@@ -1,35 +1,19 @@
 //! `cargo horizon-mod check <file>`: what the registry checks of a submission,
 //! run anywhere: its kind's own checks (docs/api/mod-index.md), its signature
-//! when given a key, and for a mod a trial run in the sandbox: it must start,
-//! survive ticks, frames, a chat line and each of its commands (a server mod:
-//! a player joining, chatting, typing them and leaving), and import no more
-//! than its capabilities.
+//! when given a key, and for a `.hmod` that it is content only.
 use horizon_mods::{
-    Clock, GameMode, Mods, Output, Package, Player, ServerPlayer, Snapshot, Status,
+    Package,
     index::{self, Facts, Kind},
-    manifest::component_imports,
 };
 use serde_json::{Value, json};
 use std::path::Path;
 
-/// How long the trial run plays: two seconds of game.
-const TICKS: u64 = 40;
-const FRAMES_PER_TICK: u64 = 3;
-
 pub struct Report {
     pub kind: Kind,
     pub facts: Facts,
     pub sha256: String,
     pub size: u64,
     pub signed: bool,
-    /// A mod has code to run (a content mod may have none).
-    pub code: bool,
-    /// A mod's component imports.
-    pub imports: Vec<String>,
-    /// A mod's commands, each run once.
-    pub commands: Vec<String>,
-    /// What the mod showed during the trial run.
-    pub output: Vec<String>,
 }
 
 impl Report {
@@ -53,10 +37,6 @@ impl Report {
             "sha256": self.sha256,
             "size": self.size,
             "signed": self.signed,
-            "code": self.code,
-            "imports": self.imports,
-            "commands": self.commands,
-            "output": self.output,
         })
     }
 
@@ -97,18 +77,11 @@ impl Report {
         for r in &f.requires {
             out += &format!("  needs {} {} ({})\n", r.id, r.version, &r.sha256[..12]);
         }
-        if self.kind == Kind::Mod && !self.code {
+        if self.kind == Kind::NativeMod {
+            out += "  native source: unsandboxed; not executed by the registry check. Compile and test against the exact pinned Horizon and Mixins revisions before review.\n";
+        }
+        if self.kind == Kind::Mod {
             out += "  no code: content only, nothing to run\n";
-        } else if self.kind == Kind::Mod {
-            let commands = if self.commands.is_empty() {
-                String::new()
-            } else {
-                format!(", /{}", self.commands.join(", /"))
-            };
-            out += &format!(
-                "  trial run: started, {TICKS} ticks, {} frames, a chat line{commands}: ok\n",
-                TICKS * FRAMES_PER_TICK
-            );
         }
         out
     }
@@ -118,6 +91,7 @@ impl Report {
 pub fn kind_of(path: &Path) -> Option<Kind> {
     match path.extension()?.to_str()? {
         "hmod" => Some(Kind::Mod),
+        "hnmod" => Some(Kind::NativeMod),
         "hpack" => Some(Kind::Modpack),
         "zip" => Some(Kind::ResourcePack),
         "hshader" => Some(Kind::Shader),
@@ -149,133 +123,26 @@ pub fn check(
         (None, None) => false,
         _ => return Err("--key and --signature go together".into()),
     };
-    let mut report = Report {
+    if kind == Kind::Mod {
+        content_only(path)?;
+    }
+    Ok(Report {
         kind,
         facts,
         sha256: index::sha256_file(path)?,
         size,
         signed,
-        code: false,
-        imports: Vec::new(),
-        commands: Vec::new(),
-        output: Vec::new(),
-    };
-    if report.kind == Kind::Mod {
-        trial_run(path, &mut report)?;
-    }
-    Ok(report)
+    })
 }
 
-/// Runs a mod in the sandbox, as the game does, from a scratch copy so its
-/// storage lands in a folder removed afterwards. A content mod has no code to
-/// run: `inspect` already read its content as the game does.
-fn trial_run(path: &Path, report: &mut Report) -> Result<(), String> {
-    let package = Package::read(path)?;
-    let Some(wasm) = package.wasm.as_deref() else {
-        return Ok(());
-    };
-    report.code = true;
-    report.imports = component_imports(wasm)?;
-    package
-        .manifest
-        .check_imports(report.imports.iter().map(String::as_str))?;
-    let dir = std::env::temp_dir().join(format!("horizon-mod-check-{}", std::process::id()));
-    let _ = std::fs::remove_dir_all(&dir);
-    std::fs::create_dir_all(&dir).map_err(|e| e.to_string())?;
-    let copy = dir.join("mod.hmod");
-    let result = std::fs::copy(path, &copy)
-        .map_err(|e| e.to_string())
-        .and_then(|_| play(&copy, report));
-    let _ = std::fs::remove_dir_all(&dir);
-    result
-}
-
-fn play(path: &Path, report: &mut Report) -> Result<(), String> {
-    let mut mods = Mods::load(&[path.to_path_buf()], |_| true, |_| false);
-    let failed = |mods: &Mods| match &mods.entries()[0].status {
-        Status::Failed(reason) => Some(reason.clone()),
-        _ => None,
-    };
-    if let Some(reason) = failed(&mods) {
-        return Err(format!("it didn't start: {reason}"));
-    }
-    let client: Vec<String> = mods.commands().map(str::to_owned).collect();
-    let server: Vec<String> = mods.server_commands().map(str::to_owned).collect();
-    report.commands = [client.clone(), server.clone()].concat();
-    // A server mod plays with one player on, who joins, chats and leaves.
-    let steve = ServerPlayer {
-        id: "00000000-0000-4000-8000-000000000001".into(),
-        name: "Steve".into(),
-        x: 0.5,
-        y: 64.0,
-        z: 0.5,
-        dimension: "minecraft:overworld".into(),
-        game_mode: GameMode::Survival,
-        health: 20.0,
-    };
-    let snapshot = |t: u64| Snapshot {
-        player: Some(Player {
-            x: 0.5 + t as f64 * 0.1,
-            y: 64.0,
-            z: 0.5,
-            yaw: 90.0,
-            pitch: 0.0,
-            health: 20.0,
-            food: 20,
-            dimension: "minecraft:overworld".into(),
-        }),
-        clock: Some(Clock {
-            game_time: t,
-            day_time: 1000 + t,
-        }),
-        players: vec![steve.clone()],
-        // The GUI of a 1280 x 720 window at scale 3.
-        gui_size: (427.0, 240.0),
-        ..Snapshot::default()
-    };
-    mods.set_snapshot(snapshot(0));
-    mods.player_joined(&steve);
-    for t in 0..TICKS {
-        mods.set_snapshot(snapshot(t));
-        mods.tick(t);
-        mods.server_tick(t);
-        for _ in 0..FRAMES_PER_TICK {
-            mods.frame(1.0 / 60.0);
-        }
-    }
-    mods.chat("<Steve> hello");
-    mods.player_chat(&steve, "hello");
-    for name in &client {
-        mods.command(name);
-    }
-    for name in &server {
-        mods.server_command(&steve, name);
-    }
-    mods.set_snapshot(Snapshot::default());
-    mods.player_left(&steve);
-    for out in mods.drain() {
-        report.output.push(match out {
-            Output::Chat { text, .. } => format!("chat: {text}"),
-            Output::Tell { text, .. } => format!("tell: {text}"),
-            Output::Broadcast { text, .. } => format!("broadcast: {text}"),
-            Output::Feedback { text, error } | Output::Reply { text, error, .. } => {
-                format!("{}: {text}", if error { "error" } else { "feedback" })
-            }
-            Output::Command { line } => format!("command: /{line}"),
-            Output::Stopped { reason, .. } => return Err(format!("it stopped: {reason}")),
-            Output::OpenScreen { .. } => "opened a screen".to_string(),
-            Output::CloseScreen { .. } => "closed its screen".to_string(),
-            Output::Shake { strength, seconds } => {
-                format!("shook the camera: {strength:.2} for {seconds:.1} s")
-            }
-        });
-    }
-    let shapes = mods.hud_shapes().count();
-    if shapes > 0 {
-        report.output.push(format!("drew {shapes} HUD shape(s)"));
-    }
-    match failed(&mods) {
-        Some(reason) => Err(format!("it stopped: {reason}")),
+/// A mod is content only: WebAssembly code mods don't run any more, code mods are native
+/// (`.hnmod`, docs/native-mods.md). `inspect` already read its content as the game does.
+fn content_only(path: &Path) -> Result<(), String> {
+    match Package::read(path)?.wasm {
+        Some(_) => Err(
+            "it has WebAssembly code, which Horizon doesn't run any more: make it a native mod (docs/native-mods.md)"
+                .into(),
+        ),
         None => Ok(()),
     }
 }
@@ -300,7 +167,7 @@ mod tests {
                 .text()
                 .contains("cozy 1.0.0 (modpack, format 1, for 26.3)")
         );
-        // The fixture mod's code is a stand-in: its manifest reads, its run fails.
+        // A mod with WebAssembly code is refused: code mods are native.
         let hmod = fixture("coords_hud-0.1.0.hmod");
         let key = std::fs::read_to_string(fixture("test.pub")).unwrap();
         let sig = std::fs::read_to_string(fixture("coords_hud-0.1.0.hmod.minisig")).unwrap();
@@ -308,7 +175,7 @@ mod tests {
         let e = check(&hmod, Kind::Mod, Some(key), Some(&sig))
             .err()
             .unwrap();
-        assert!(e.contains("didn't start"), "{e}");
+        assert!(e.contains("native mod"), "{e}");
         let e = check(
             &hmod,
             Kind::Mod,

crates/cargo-horizon-mod/src/main.rs

@@ -1,32 +1,23 @@
-//! `cargo horizon-mod`: make Horizon mods in Rust (`docs/mods.md`).
+//! `cargo horizon-mod`: make Horizon content mods (`docs/modpacks.md`): blocks,
+//! items, data and assets, no code. Code mods are native (docs/native-mods.md).
 //!
-//! - `new <path> [--template code|content] [--name "Name"] [--sdk-path <dir>]`:
-//!   a mod from a template: a Rust crate, or a content mod (no code).
-//! - `build [--debug]`: the `.hmod` in `target/horizon-mod/`, with the mod's
-//!   `assets/` and `data/`; a folder without `Cargo.toml` is content only.
+//! - `new <path> [--name "Name"]`: a content mod from the template.
+//! - `build`: the `.hmod` in `target/horizon-mod/`, with the mod's `assets/`
+//!   and `data/`.
 //! - `run [--game <horizon-client>] [-- <game args>]`: build, then play with
-//!   the mod; run `build` again and the game reloads it.
-//! - `test [--debug] [--hmod <file>] [<name>]`: build, then run the mod's
-//!   `tests/*.toml` scripts in the sandbox, with no game.
+//!   the mod.
 //! - `check <file> [--json]`: what the registry checks of a submission
-//!   (`.hmod`, `.hpack`, resource pack `.zip`), with a trial run for a mod.
+//!   (`.hmod`, `.hnmod`, `.hpack`, resource pack `.zip`, `.hshader`).
 //! - `registry build|review|check|list`: the registry repository's CI.
-use horizon_mods::{
-    Capability, Content, Manifest, Package,
-    manifest::{MANIFEST, component_imports, componentize},
-    testing::{Script, TestGame},
-};
+use horizon_mods::{Capability, Content, Manifest, Package, manifest::MANIFEST};
 mod check;
 mod registry;
 
 use std::{
     path::{Path, PathBuf},
-    process::{Command, ExitCode, Stdio},
+    process::{Command, ExitCode},
 };
 
-const TARGET: &str = "wasm32-unknown-unknown";
-const SDK_GIT: &str = "{ git = \"https://github.com/ludovic111/horizon\" }";
-
 fn main() -> ExitCode {
     // Cargo runs `cargo-horizon-mod horizon-mod <args>`.
     let mut args: Vec<String> = std::env::args().skip(1).collect();
@@ -35,14 +26,13 @@ fn main() -> ExitCode {
     }
     let result = match args.first().map(String::as_str) {
         Some("new") => new(&args[1..]),
-        Some("build") => build(!args.iter().any(|a| a == "--debug")).map(|p| {
+        Some("build") => build().map(|p| {
             println!("Built {}", p.display());
         }),
         Some("run") => run(&args[1..]),
-        Some("test") => test(&args[1..]),
         Some("check") => check(&args[1..]),
         Some("registry") => registry::main(&args[1..]),
-        _ => Err("usage: cargo horizon-mod new <path> [--template code|content] | build [--debug] | run [--game <horizon-client>] [-- <game args>] | test [--debug] [--hmod <file>] [<name>] | check <file> [--kind <kind>] [--key <public key> --signature <file.minisig>] [--json] | registry build|review|check|list".into()),
+        _ => Err("usage: cargo horizon-mod new <path> [--name \"Name\"] | build | run [--game <horizon-client>] [-- <game args>] | check <file> [--kind <kind>] [--key <public key> --signature <file.minisig>] [--json] | registry build|review|check|list".into()),
     };
     match result {
         Ok(()) => ExitCode::SUCCESS,
@@ -83,31 +73,9 @@ fn new(args: &[String]) -> Result<(), String> {
         })
         .collect();
     let name = flag(args, "--name").map_or_else(|| base.replace(['-', '_'], " "), str::to_string);
-    let sdk = match flag(args, "--sdk-path") {
-        Some(p) => {
-            let p = std::fs::canonicalize(p).map_err(|e| format!("--sdk-path {p}: {e}"))?;
-            format!("{{ path = {:?} }}", p.display().to_string())
-        }
-        None => SDK_GIT.to_string(),
-    };
-    let fill = |t: &str| {
-        t.replace("{crate}", &id.replace('_', "-"))
-            .replace("{id}", &id)
-            .replace("{name}", &name)
-            .replace("{sdk}", &sdk)
-    };
-    let code = [
-        ("Cargo.toml", include_str!("../template/Cargo.toml.in")),
-        (MANIFEST, include_str!("../template/horizon-mod.toml")),
-        ("src/lib.rs", include_str!("../template/src/lib.rs")),
-        (".gitignore", include_str!("../template/gitignore")),
-        (
-            "tests/hello.toml",
-            include_str!("../template/tests/hello.toml"),
-        ),
-    ];
+    let fill = |t: &str| t.replace("{id}", &id).replace("{name}", &name);
     // A block copying a vanilla one, with its model, name, loot, recipe and tag.
-    let content = [
+    let files = [
         (
             MANIFEST,
             include_str!("../template/content/horizon-mod.toml"),
@@ -146,12 +114,12 @@ fn new(args: &[String]) -> Result<(), String> {
         ),
         (".gitignore", include_str!("../template/gitignore")),
     ];
-    let files: &[(&str, &str)] = match flag(args, "--template").unwrap_or("code") {
-        "code" => &code,
-        "content" => &content,
-        other => return Err(format!("no template {other}: code or content")),
-    };
-    for &(file, text) in files {
+    if flag(args, "--template").is_some_and(|t| t != "content") {
+        return Err(
+            "only content mods are made here: code mods are native (docs/native-mods.md)".into(),
+        );
+    }
+    for (file, text) in files {
         let file = fill(file);
         let file = file.as_str();
         let to = dir.join(file);
@@ -169,29 +137,24 @@ fn new(args: &[String]) -> Result<(), String> {
     Ok(())
 }
 
-/// Builds the mod in the current folder and packs `target/horizon-mod/<id>.hmod`:
-/// the manifest, the crate's component (none without a `Cargo.toml`: a
-/// content mod) and the files in `assets/` and `data/`.
-fn build(release: bool) -> Result<PathBuf, String> {
-    build_in(Path::new("."), release)
+/// Packs the content mod in the current folder into `target/horizon-mod/<id>.hmod`: the
+/// manifest and the files in `assets/` and `data/`.
+fn build() -> Result<PathBuf, String> {
+    build_in(Path::new("."))
 }
 
-fn build_in(root: &Path, release: bool) -> Result<PathBuf, String> {
+fn build_in(root: &Path) -> Result<PathBuf, String> {
     let manifest_text = std::fs::read_to_string(root.join(MANIFEST))
         .map_err(|e| format!("{MANIFEST}: {e} (run this in a mod's folder)"))?;
     let manifest = Manifest::parse(&manifest_text)?;
-    let (wasm, target_dir) = if root.join("Cargo.toml").exists() {
-        let (wasm, target) = compile(root, release)?;
-        // The game refuses a component importing capabilities the manifest lacks.
-        manifest.check_imports(component_imports(&wasm)?.iter().map(String::as_str))?;
-        (Some(wasm), target)
-    } else if manifest.capabilities.contains(&Capability::Registries) {
-        (None, root.join("target"))
-    } else {
+    if root.join("Cargo.toml").exists() {
+        return Err("a Cargo.toml: code mods are native now (docs/native-mods.md)".into());
+    }
+    if !manifest.capabilities.contains(&Capability::Registries) {
         return Err(format!(
-            "no Cargo.toml: only a content mod (capability registries in {MANIFEST}) has no code"
+            "a content mod has capability registries in {MANIFEST}"
         ));
-    };
+    }
     // The same checks as the game's, and the files in the order it lists them.
     let content = Content::read(root, &manifest)?;
     let mut reader = content.reader()?;
@@ -200,53 +163,17 @@ fn build_in(root: &Path, release: bool) -> Result<PathBuf, String> {
         files.push((name.as_str(), reader.read(name)?));
     }
     let files: Vec<(&str, &[u8])> = files.iter().map(|(n, b)| (*n, b.as_slice())).collect();
-    let dir = target_dir.join("horizon-mod");
+    let dir = root.join("target/horizon-mod");
     std::fs::create_dir_all(&dir).map_err(|e| e.to_string())?;
     let path = dir.join(format!("{}.hmod", manifest.id));
     // Write then rename, so a running game never reads half a file.
     let partial = path.with_extension("hmod.partial");
-    let bytes = Package::write_files(&manifest_text, wasm.as_deref(), &files)?;
+    let bytes = Package::write_files(&manifest_text, None, &files)?;
     std::fs::write(&partial, bytes).map_err(|e| e.to_string())?;
     std::fs::rename(&partial, &path).map_err(|e| e.to_string())?;
     Ok(path)
 }
 
-/// Builds the crate for WebAssembly: its component, and Cargo's target folder.
-fn compile(root: &Path, release: bool) -> Result<(Vec<u8>, PathBuf), String> {
-    let cargo = std::env::var("CARGO").unwrap_or_else(|_| "cargo".into());
-    let mut cmd = Command::new(cargo);
-    cmd.current_dir(root).args([
-        "build",
-        "--lib",
-        "--target",
-        TARGET,
-        "--message-format=json-render-diagnostics",
-    ]);
-    if release {
-        cmd.arg("--release");
-    }
-    let out = cmd
-        .stderr(Stdio::inherit())
-        .output()
-        .map_err(|e| e.to_string())?;
-    if !out.status.success() {
-        return Err(format!(
-            "cargo build failed (is the target installed? rustup target add {TARGET})"
-        ));
-    }
-    let core = String::from_utf8_lossy(&out.stdout)
-        .lines()
-        .filter_map(|l| serde_json::from_str::<serde_json::Value>(l).ok())
-        .filter(|m| m["reason"] == "compiler-artifact")
-        .flat_map(|m| m["filenames"].as_array().cloned().unwrap_or_default())
-        .filter_map(|f| f.as_str().map(PathBuf::from))
-        .rfind(|f| f.extension().is_some_and(|e| e == "wasm"))
-        .ok_or("the build made no .wasm: is the crate a cdylib?")?;
-    let wasm = componentize(&std::fs::read(&core).map_err(|e| e.to_string())?)?;
-    let target = core.ancestors().nth(3).ok_or("unexpected target folder")?;
-    Ok((wasm, target.to_path_buf()))
-}
-
 /// `check <file>`: the registry's checks of a submission, printed; fails
 /// when one does.
 fn check(args: &[String]) -> Result<(), String> {
@@ -278,74 +205,14 @@ fn check(args: &[String]) -> Result<(), String> {
     Ok(())
 }
 
-/// `test`: every `tests/*.toml` script (those whose name holds `<name>`)
-/// against the built mod, or the `.hmod` given with `--hmod`.
-fn test(args: &[String]) -> Result<(), String> {
-    let hmod = match flag(args, "--hmod") {
-        Some(p) => PathBuf::from(p),
-        None => build(!args.iter().any(|a| a == "--debug"))?,
-    };
-    let filter = args
-        .iter()
-        .enumerate()
-        .find(|(i, a)| !a.starts_with("--") && (*i == 0 || args[i - 1] != "--hmod"))
-        .map(|(_, a)| a.as_str());
-    let mut scripts: Vec<PathBuf> = std::fs::read_dir("tests")
-        .map_err(|e| {
-            format!(
-                "tests/: {e} (a mod's tests are tests/<name>.toml: docs/mods.md, \"Testing a mod\")"
-            )
-        })?
-        .filter_map(|e| Some(e.ok()?.path()))
-        .filter(|p| p.extension().is_some_and(|e| e == "toml"))
-        .filter(|p| filter.is_none_or(|f| p.to_string_lossy().contains(f)))
-        .collect();
-    scripts.sort();
-    if scripts.is_empty() {
-        return Err("no tests/*.toml to run".into());
-    }
-    println!(
-        "running {} scripts against {}",
-        scripts.len(),
-        hmod.display()
-    );
-    let mut failed = 0;
-    for path in &scripts {
-        let result = std::fs::read_to_string(path)
-            .map_err(|e| e.to_string())
-            .and_then(|text| Script::parse(&text))
-            .and_then(|script| {
-                let mut game = TestGame::load(&hmod)?;
-                script.run(&mut game)?;
-                Ok(script.steps.len())
-            });
-        match result {
-            Ok(steps) => println!("test {} ... ok ({steps} steps)", path.display()),
-            Err(e) => {
-                failed += 1;
-                println!("test {} ... FAILED\n  {e}", path.display());
-            }
-        }
-    }
-    let passed = scripts.len() - failed;
-    if failed > 0 {
-        return Err(format!("{failed} failed, {passed} passed"));
-    }
-    println!("test result: ok. {passed} passed");
-    Ok(())
-}
-
 fn run(args: &[String]) -> Result<(), String> {
-    let path = build(true)?;
+    let path = build()?;
     let game = flag(args, "--game")
         .map(str::to_string)
         .or_else(|| std::env::var("HORIZON_CLIENT").ok())
         .unwrap_or_else(|| "horizon-client".into());
     let extra = args.iter().skip_while(|a| *a != "--").skip(1);
-    println!(
-        "Starting {game} with {} (rebuild with `cargo horizon-mod build` to reload it)",
-        path.display()
-    );
+    println!("Starting {game} with {}", path.display());
     let status = Command::new(&game)
         .arg("--dev-mod")
         .arg(&path)
@@ -364,28 +231,6 @@ fn run(args: &[String]) -> Result<(), String> {
 mod tests {
     use super::*;
 
-    #[test]
-    fn the_template_is_a_valid_mod() {
-        let dir = std::env::temp_dir().join(format!("horizon-mod-new-{}", std::process::id()));
-        let path = dir.join("My-Mod");
-        new(&[path.display().to_string(), "--name".into(), "My Mod".into()]).unwrap();
-        let manifest =
-            Manifest::parse(&std::fs::read_to_string(path.join(MANIFEST)).unwrap()).unwrap();
-        assert_eq!(
-            (manifest.id.as_str(), manifest.name.as_str()),
-            ("my_mod", "My Mod")
-        );
-        let cargo = std::fs::read_to_string(path.join("Cargo.toml")).unwrap();
-        assert!(cargo.contains("name = \"my-mod\"") && cargo.contains(SDK_GIT));
-        let script = std::fs::read_to_string(path.join("tests/hello.toml")).unwrap();
-        assert_eq!(Script::parse(&script).unwrap().steps.len(), 3);
-        assert!(
-            new(&[path.display().to_string()]).is_err(),
-            "never overwrites"
-        );
-        std::fs::remove_dir_all(&dir).unwrap();
-    }
-
     #[test]
     fn the_content_template_builds_and_checks_with_no_code() {
         let dir = std::env::temp_dir().join(format!("horizon-mod-content-{}", std::process::id()));
@@ -397,7 +242,7 @@ mod tests {
         ];
         new(&new_args).unwrap();
         assert!(!path.join("Cargo.toml").exists());
-        let hmod = build_in(&path, true).unwrap();
+        let hmod = build_in(&path).unwrap();
         assert_eq!(hmod, path.join("target/horizon-mod/gems.hmod"));
         let package = Package::read(&hmod).unwrap();
         assert!(package.wasm.is_none());
@@ -409,17 +254,14 @@ mod tests {
         );
         assert_eq!(content.files.len(), 8, "{:?}", content.files);
         let report = check::check(&hmod, check::kind_of(&hmod).unwrap(), None, None).unwrap();
-        assert!(!report.code);
         assert!(
             report.text().contains("no code: content only"),
             "{}",
             report.text()
         );
-        // Without registries, a mod needs code.
-        let manifest = std::fs::read_to_string(path.join(MANIFEST)).unwrap();
-        let manifest = manifest.replace("[\"registries\"]", "[]");
-        std::fs::write(path.join(MANIFEST), manifest).unwrap();
-        assert!(build_in(&path, true).unwrap_err().contains("no Cargo.toml"));
+        // Code is native now.
+        std::fs::write(path.join("Cargo.toml"), "").unwrap();
+        assert!(build_in(&path).unwrap_err().contains("native"));
         assert!(
             new(&[
                 dir.join("x").display().to_string(),

crates/cargo-horizon-mod/src/registry.rs

@@ -1,5 +1,5 @@
 //! `cargo horizon-mod registry build|review|check|list`: the registry repository's CI
-//! (`ludovic111/horizon-mods`, docs/api/mod-index.md). Network-free: the
+//! (`horizon-rust/horizon-mods`, docs/api/mod-index.md). Network-free: the
 //! workflow downloads the files and publishes what this writes.
 use horizon_mods::index::{
     FILE_HOST,
@@ -8,7 +8,7 @@ use horizon_mods::index::{
 use std::path::Path;
 
 /// Where the registry's site is published (its icons).
-const SITE: &str = "https://ludovic111.github.io/horizon-mods/";
+const SITE: &str = "https://horizon-rust.github.io/horizon-mods/";
 
 const USAGE: &str = "usage: cargo horizon-mod registry build <checkout> --files <dir> --out <index.json> [--release <url>] [--site <url>] [--generated <time>]
        cargo horizon-mod registry review <base checkout> <head checkout> --author <login> [--json]

crates/cargo-horizon-mod/template/Cargo.toml.in

@@ -1,14 +0,0 @@
-[package]
-name = "{crate}"
-version = "0.1.0"
-edition = "2024"
-
-[lib]
-crate-type = ["cdylib"]
-
-[dependencies]
-horizon-mod-sdk = {sdk}
-
-[profile.release]
-opt-level = "s"
-lto = true

crates/cargo-horizon-mod/template/horizon-mod.toml

@@ -1,12 +0,0 @@
-id = "{id}"
-name = "{name}"
-version = "0.1.0"
-description = ""
-authors = []
-# The Horizon mod API the SDK targets.
-api = "0.1"
-# client: runs in the player's game.
-side = "client"
-# What the mod may do, shown to players before they turn it on:
-# game-read (position, health, time), chat (show messages), hud (draw text).
-capabilities = ["chat"]

crates/cargo-horizon-mod/template/src/lib.rs

@@ -1,19 +0,0 @@
-use horizon_mod_sdk::{Mod, Registration, chat};
-
-struct MyMod {
-    greeted: u32,
-}
-
-impl Mod for MyMod {
-    fn init() -> Result<(Self, Registration), String> {
-        Ok((MyMod { greeted: 0 }, Registration::new().command("hello")))
-    }
-
-    fn command(&mut self, _name: &str, args: &str) -> Result<Option<String>, String> {
-        self.greeted += 1;
-        chat::show(&format!("Hello {args}! ({} so far)", self.greeted));
-        Ok(None)
-    }
-}
-
-horizon_mod_sdk::export_mod!(MyMod);

crates/cargo-horizon-mod/template/tests/hello.toml

@@ -1,14 +0,0 @@
-# `cargo horizon-mod test` runs every tests/*.toml against the built mod, with no game:
-# steps happen in order, and `expect` checks what the mod showed during the step.
-# Every key: docs/mods.md, "Testing a mod".
-
-[[step]]
-expect.commands = ["hello"]
-
-[[step]]
-command = "hello world"
-expect.chat = ["Hello world! (1 so far)"]
-
-[[step]]
-command = "hello again"
-expect.chat = ["Hello again! (2 so far)"]

crates/horizon-assets/src/item_model.rs

@@ -1031,19 +1031,22 @@ pub struct ItemModels {
 }
 
 impl ItemModels {
-    pub fn components(&self, stack: &StackView) -> Components {
-        let mut out = self
-            .prototypes
-            .get(&stack.item)
-            .cloned()
-            .unwrap_or_default();
+    /// The stack's components: its item's defaults with the stack's patch on top. A stack
+    /// with no patch (most stacks a screen draws) borrows the defaults instead of copying them.
+    pub fn components(&self, stack: &StackView) -> std::borrow::Cow<'_, Components> {
+        static NONE: Components = BTreeMap::new();
+        let prototype = self.prototypes.get(&stack.item).unwrap_or(&NONE);
+        if stack.patch.is_empty() {
+            return std::borrow::Cow::Borrowed(prototype);
+        }
+        let mut out = prototype.clone();
         for (key, value) in &stack.patch {
             match value {
                 Some(v) => out.insert(key.clone(), v.clone()),
                 None => out.remove(key),
             };
         }
-        out
+        std::borrow::Cow::Owned(out)
     }
     /// `ItemModelResolver.updateForTopItem`.
     pub fn resolve(&self, stack: &StackView, ctx: &Context, env: &dyn ItemEnv) -> ResolvedItem {

crates/horizon-client-core/Cargo.toml

@@ -0,0 +1,14 @@
+[package]
+name = "horizon-client-core"
+version = "0.1.0"
+edition.workspace = true
+license.workspace = true
+rust-version = "1.90"
+description = "The client's lowest layer: chat text and translations, SNBT and NBT paths, the scoreboard, boss bars, game rules and the registry and particle tables commands name"
+
+[dependencies]
+horizon-world = { path = "../horizon-world" }
+serde_json = { version = "1.0.151", features = ["raw_value"] }
+
+[lints]
+workspace = true

crates/horizon-client-core/src/block_entity_nbt.rs

@@ -61,6 +61,16 @@ fn f32_tag(v: f32) -> Tag {
     Tag::Float(v.to_bits())
 }
 
+/// `TheEndGatewayBlockEntity.loadAdditional`: BlockPos.CODEC and Level.isInSpawnableBounds.
+pub fn gateway_exit(tag: &Tag) -> Option<[i32; 3]> {
+    let Tag::IntArray(v) = tag else { return None };
+    let p: [i32; 3] = v.as_slice().try_into().ok()?;
+    ((-30_000_000..30_000_000).contains(&p[0])
+        && (-20_000_000..20_000_000).contains(&p[1])
+        && (-30_000_000..30_000_000).contains(&p[2]))
+    .then_some(p)
+}
+
 /// What a block entity reads and writes, in `saveAdditional` order.
 struct Fields<'a> {
     input: &'a Tag,
@@ -259,7 +269,7 @@ fn is_pos(tag: &Tag) -> bool {
     matches!(tag, Tag::IntArray(v) if v.len() == 3)
 }
 /// The loaded `SignText` of one side, or the empty text.
-pub(crate) fn sign_side(tag: Option<&Tag>) -> Tag {
+pub fn sign_side(tag: Option<&Tag>) -> Tag {
     let empty = || string("");
     let mut messages: Vec<Tag> = match tag.and_then(|t| t.get("messages")) {
         Some(Tag::List(list)) => list.iter().filter_map(component).collect(),
@@ -424,10 +434,7 @@ pub fn canonical(tag: &Tag) -> Option<Tag> {
         }
         "minecraft:end_gateway" => {
             f.long("Age", 0);
-            f.keep("exit_portal", |t| {
-                is_pos(t)
-                    && matches!(t, Tag::IntArray(v) if v[1].abs() <= 30_000_000 && v[0].abs() <= 30_000_000 && v[2].abs() <= 30_000_000)
-            });
+            f.keep("exit_portal", |t| gateway_exit(t).is_some());
             if flag(tag.get("ExactTeleport")) == Some(true) {
                 f.put("ExactTeleport", boolean(true));
             }
@@ -487,7 +494,11 @@ pub fn canonical(tag: &Tag) -> Option<Tag> {
                     _ => string("minecraft:air"),
                 },
             );
-            f.put("facing", Tag::Int(int(tag.get("facing")).unwrap_or(0)));
+            // Direction.LEGACY_ID_CODEC: the 3D data value as a byte.
+            f.put(
+                "facing",
+                Tag::Byte(int(tag.get("facing")).unwrap_or(0) as i8),
+            );
             f.float("progress", 0.0);
             f.flag("extending", false);
             f.flag("source", false);
@@ -866,6 +877,23 @@ mod tests {
         );
     }
 
+    /// `PistonMovingBlockEntity.saveAdditional`: `facing` through
+    /// `Direction.LEGACY_ID_CODEC` (a byte), `progress` a float.
+    #[test]
+    fn moving_piston_fields_match_vanilla() {
+        let out = canon(
+            "{id:\"minecraft:piston\",x:1,y:2,z:3,blockState:{Name:\"minecraft:stone\"},\
+             facing:5,progress:0.5f,extending:1b,source:0b}",
+        );
+        assert_eq!(out.get("facing"), Some(&Tag::Byte(5)));
+        assert_eq!(out.get("progress"), Some(&f32_tag(0.5)));
+        assert_eq!(out.get("extending"), Some(&Tag::Byte(1)));
+        assert_eq!(out.get("source"), Some(&Tag::Byte(0)));
+        let fresh = canon("{id:\"minecraft:piston\",x:1,y:2,z:3}");
+        assert_eq!(fresh.get("facing"), Some(&Tag::Byte(0)));
+        assert_eq!(fresh.get("blockState"), Some(&string("minecraft:air")));
+    }
+
     #[test]
     fn loot_table_replaces_items_and_zero_seed_is_omitted() {
         let out = canon(

crates/horizon-client-core/src/component.rs

@@ -0,0 +1,549 @@
+//! Text components from commands: `ComponentArgument` reads an SNBT (or JSON)
+//! value, `ComponentSerialization` turns it into styled text.
+use crate::text::{InlineObject, Style, Text, named_color};
+use horizon_world::nbt::Tag;
+use serde_json::{Map, Value};
+
+/// `SnbtGrammar`, enough for components: compounds, lists, quoted and
+/// unquoted strings, numbers (with type suffixes) and booleans. Returns the
+/// value and the bytes consumed.
+pub fn parse_snbt(input: &str) -> Result<(Value, usize), String> {
+    let mut p = Parser {
+        s: input.as_bytes(),
+        i: 0,
+        depth: 0,
+    };
+    let v = p.value()?;
+    Ok((v, p.i))
+}
+/// Nesting deeper than NBT's own limit (`NbtAccounter`'s 512) is refused
+/// rather than overflowing the stack.
+const SNBT_MAX_DEPTH: usize = 512;
+struct Parser<'a> {
+    s: &'a [u8],
+    i: usize,
+    depth: usize,
+}
+impl Parser<'_> {
+    fn ws(&mut self) {
+        while self.i < self.s.len() && self.s[self.i].is_ascii_whitespace() {
+            self.i += 1;
+        }
+    }
+    fn peek(&self) -> Option<u8> {
+        self.s.get(self.i).copied()
+    }
+    fn expect(&mut self, c: u8) -> Result<(), String> {
+        self.ws();
+        if self.peek() == Some(c) {
+            self.i += 1;
+            Ok(())
+        } else {
+            Err(format!("expected '{}'", c as char))
+        }
+    }
+    fn value(&mut self) -> Result<Value, String> {
+        self.ws();
+        match self.peek() {
+            Some(b'{') => {
+                if self.depth >= SNBT_MAX_DEPTH {
+                    return Err(format!("tag nesting too deep at {}", self.i));
+                }
+                self.depth += 1;
+                let v = self.object();
+                self.depth -= 1;
+                v
+            }
+            Some(b'[') => {
+                if self.depth >= SNBT_MAX_DEPTH {
+                    return Err(format!("tag nesting too deep at {}", self.i));
+                }
+                self.depth += 1;
+                let v = self.array();
+                self.depth -= 1;
+                v
+            }
+            Some(b'"' | b'\'') => Ok(Value::String(self.string()?)),
+            Some(_) => {
+                let word = self.unquoted();
+                if word.is_empty() {
+                    return Err("expected a value".into());
+                }
+                Ok(match word.as_str() {
+                    "true" => Value::Bool(true),
+                    "false" => Value::Bool(false),
+                    _ => {
+                        let digits = word
+                            .trim_end_matches(['b', 'B', 's', 'S', 'l', 'L', 'f', 'F', 'd', 'D']);
+                        // Only digits (and an exponent) make a number: `nan`
+                        // or `Infinity`, which Rust's parse would take, stays
+                        // a string.
+                        if digits
+                            .bytes()
+                            .any(|c| c.is_ascii_alphabetic() && c != b'e' && c != b'E')
+                        {
+                            Value::String(word)
+                        } else {
+                            match (digits.parse::<i64>(), digits.parse::<f64>()) {
+                                (Ok(n), _) if digits.len() + 1 >= word.len() => Value::from(n),
+                                (_, Ok(f)) if digits.len() + 1 >= word.len() => Value::from(f),
+                                _ => Value::String(word),
+                            }
+                        }
+                    }
+                })
+            }
+            None => Err("expected a value".into()),
+        }
+    }
+    fn object(&mut self) -> Result<Value, String> {
+        self.i += 1;
+        let mut map = Map::new();
+        self.ws();
+        if self.peek() == Some(b'}') {
+            self.i += 1;
+            return Ok(Value::Object(map));
+        }
+        loop {
+            self.ws();
+            let key = self.string()?;
+            self.expect(b':')?;
+            map.insert(key, self.value()?);
+            self.ws();
+            match self.peek() {
+                Some(b',') => self.i += 1,
+                Some(b'}') => {
+                    self.i += 1;
+                    return Ok(Value::Object(map));
+                }
+                _ => return Err("expected ',' or '}'".into()),
+            }
+        }
+    }
+    fn array(&mut self) -> Result<Value, String> {
+        self.i += 1;
+        let mut list = Vec::new();
+        self.ws();
+        // Typed arrays [B;...], [I;...], [L;...].
+        if matches!(
+            self.s.get(self.i..self.i + 2),
+            Some([b'B' | b'I' | b'L', b';'])
+        ) {
+            self.i += 2;
+        }
+        self.ws();
+        if self.peek() == Some(b']') {
+            self.i += 1;
+            return Ok(Value::Array(list));
+        }
+        loop {
+            list.push(self.value()?);
+            self.ws();
+            match self.peek() {
+                Some(b',') => self.i += 1,
+                Some(b']') => {
+                    self.i += 1;
+                    return Ok(Value::Array(list));
+                }
+                _ => return Err("expected ',' or ']'".into()),
+            }
+        }
+    }
+    fn unquoted(&mut self) -> String {
+        let start = self.i;
+        while let Some(c) = self.peek() {
+            if c.is_ascii_alphanumeric() || matches!(c, b'_' | b'-' | b'.' | b'+') {
+                self.i += 1;
+            } else {
+                break;
+            }
+        }
+        String::from_utf8_lossy(&self.s[start..self.i]).into_owned()
+    }
+    fn string(&mut self) -> Result<String, String> {
+        self.ws();
+        let Some(q @ (b'"' | b'\'')) = self.peek() else {
+            return Ok(self.unquoted());
+        };
+        self.i += 1;
+        let mut out = Vec::new();
+        while let Some(c) = self.peek() {
+            self.i += 1;
+            match c {
+                b'\\' => {
+                    let Some(e) = self.peek() else { break };
+                    self.i += 1;
+                    out.push(match e {
+                        b'n' => b'\n',
+                        b't' => b'\t',
+                        other => other,
+                    });
+                }
+                c if c == q => return Ok(String::from_utf8_lossy(&out).into_owned()),
+                c => out.push(c),
+            }
+        }
+        Err("unterminated string".into())
+    }
+}
+/// The style fields of a component object.
+fn object_style(o: &serde_json::Map<String, Value>) -> Style {
+    let mut style = Style::default();
+    if let Some(c) = o.get("color").and_then(Value::as_str) {
+        style.color = named_color(c).or_else(|| {
+            c.strip_prefix('#')
+                .and_then(|h| u32::from_str_radix(h, 16).ok())
+        });
+    }
+    style.shadow_color = o.get("shadow_color").and_then(shadow_color);
+    let flag = |k: &str| o.get(k).and_then(Value::as_bool);
+    style.bold = flag("bold");
+    style.italic = flag("italic");
+    style.underlined = flag("underlined");
+    style.strikethrough = flag("strikethrough");
+    style.obfuscated = flag("obfuscated");
+    style.font = o.get("font").and_then(crate::text::font_id);
+    // ClickEvent.CODEC: the actions a chat line acts on here. A component
+    // from a server never opens a file.
+    if let Some(e) = o.get("click_event").and_then(Value::as_object) {
+        let text = |k: &str| e.get(k).and_then(Value::as_str).map(str::to_owned);
+        style.click = match e.get("action").and_then(Value::as_str) {
+            // ClickEvent.OpenUrl.CODEC: ExtraCodecs.UNTRUSTED_URI allows http and
+            // https only, the scheme in any case (Util.parseAndValidateUntrustedUri).
+            Some("open_url") => text("url")
+                .filter(|u| {
+                    u.split_once(':').is_some_and(|(scheme, _)| {
+                        scheme.eq_ignore_ascii_case("http") || scheme.eq_ignore_ascii_case("https")
+                    })
+                })
+                .map(crate::text::ClickEvent::OpenUrl),
+            // ClickEvent.ChangePage.CODEC: ExtraCodecs.POSITIVE_INT.
+            Some("change_page") => e
+                .get("page")
+                .and_then(Value::as_i64)
+                .and_then(|p| i32::try_from(p).ok())
+                .filter(|p| *p >= 1)
+                .map(crate::text::ClickEvent::ChangePage),
+            Some("suggest_command") => text("command").map(crate::text::ClickEvent::SuggestCommand),
+            Some("run_command") => text("command").map(crate::text::ClickEvent::RunCommand),
+            Some("copy_to_clipboard") => {
+                text("value").map(crate::text::ClickEvent::CopyToClipboard)
+            }
+            // ClickEvent.ShowDialog.CODEC: a `minecraft:dialog` registry id or
+            // the dialog itself; the server may send it (isAllowedFromServer).
+            Some("show_dialog") => e.get("dialog").map(|dialog| {
+                crate::text::ClickEvent::ShowDialog(crate::scoreboard::json_to_tag(dialog))
+            }),
+            _ => None,
+        };
+    }
+    // HoverEvent.ShowText and ShowItem.
+    if let Some(e) = o.get("hover_event").and_then(Value::as_object) {
+        match e.get("action").and_then(Value::as_str) {
+            Some("show_text") => {
+                if let Some(value) = e.get("value") {
+                    style.hover = Some(Box::new(to_text(value, &mut |s| Text::literal(s))));
+                }
+            }
+            Some("show_item") if e.get("id").is_some_and(Value::is_string) => {
+                style.hover_item = Some(Box::new(Value::Object(e.clone())));
+            }
+            _ => {}
+        }
+    }
+    style.insertion = o
+        .get("insertion")
+        .and_then(Value::as_str)
+        .map(str::to_owned);
+    style
+}
+
+/// `Style.shadow_color`: a packed ARGB int or normalized RGBA array.
+pub(crate) fn shadow_color(value: &Value) -> Option<u32> {
+    if let Some(packed) = value.as_i64() {
+        return i32::try_from(packed).ok().map(|n| n as u32);
+    }
+    let rgba = value.as_array()?;
+    if rgba.len() != 4 {
+        return None;
+    }
+    let channels = rgba
+        .iter()
+        .map(|channel| {
+            // ExtraCodecs.ARGB_COLOR_CODEC reads floats; ARGB.as8BitChannel
+            // floors each normalized channel multiplied by 255.
+            let value = channel.as_f64()? as f32;
+            (value.is_finite() && (0.0..=1.0).contains(&value))
+                .then_some((value * 255.0_f32).floor() as u32)
+        })
+        .collect::<Option<Vec<_>>>()?;
+    Some(channels[3] << 24 | channels[0] << 16 | channels[1] << 8 | channels[2])
+}
+/// `ComponentSerialization.CODEC` decoding into text. `selector` components
+/// are resolved by `resolve` (ComponentUtils.updateForEntity).
+pub fn to_text(v: &Value, resolve: &mut dyn FnMut(&str) -> Text) -> Text {
+    to_text_with(v, resolve, &mut |_| None)
+}
+/// `to_text` with a hook resolving other contents (`nbt`) from the object.
+pub fn to_text_with(
+    v: &Value,
+    resolve: &mut dyn FnMut(&str) -> Text,
+    contents: &mut dyn FnMut(&serde_json::Map<String, Value>) -> Option<Text>,
+) -> Text {
+    match v {
+        Value::String(s) => Text::literal(s.clone()),
+        Value::Number(n) => Text::literal(n.to_string()),
+        Value::Bool(b) => Text::literal(b.to_string()),
+        // A list is its first element with the rest as siblings.
+        Value::Array(list) => {
+            let Some((first, rest)) = list.split_first() else {
+                return Text::empty();
+            };
+            let mut base = to_text_with(first, resolve, contents);
+            // The siblings take the first component's own style, even when
+            // its text is empty.
+            let style = match first {
+                Value::Object(o) => object_style(o),
+                _ => base
+                    .spans
+                    .first()
+                    .map(|s| s.style.clone())
+                    .unwrap_or_default(),
+            };
+            for sibling in rest {
+                base.push(to_text_with(sibling, resolve, contents).with_style(&style));
+            }
+            base
+        }
+        Value::Object(o) => {
+            let style = object_style(o);
+            let content = if let Some(t) = contents(o) {
+                t
+            } else if let Some(object) = inline_object(o, resolve, contents) {
+                let mut text = Text::literal("\u{fffc}");
+                text.spans[0].style.inline_object = Some(object);
+                text
+            } else if let Some(t) = o.get("text") {
+                match t {
+                    Value::String(s) => Text::literal(s.clone()),
+                    other => Text::literal(other.to_string()),
+                }
+            } else if let Some(key) = o.get("translate").and_then(Value::as_str) {
+                let args: Vec<Text> = o
+                    .get("with")
+                    .and_then(Value::as_array)
+                    .map(|a| {
+                        a.iter()
+                            .map(|x| to_text_with(x, resolve, contents))
+                            .collect()
+                    })
+                    .unwrap_or_default();
+                let translated = Text::translate(key, &args);
+                match o.get("fallback").and_then(Value::as_str) {
+                    Some(fallback) if translated.plain() == key => Text::translate(fallback, &args),
+                    _ => translated,
+                }
+            } else if let Some(sel) = o.get("selector").and_then(Value::as_str) {
+                resolve(sel)
+            } else if let Some(key) = o.get("keybind").and_then(Value::as_str) {
+                crate::key_display::display_name(key)
+            } else {
+                Text::empty()
+            };
+            let mut out = content.with_style(&style);
+            for extra in o
+                .get("extra")
+                .and_then(Value::as_array)
+                .into_iter()
+                .flatten()
+            {
+                out.push(to_text_with(extra, resolve, contents).with_style(&style));
+            }
+            if o.contains_key("object") || o.contains_key("player") || o.contains_key("sprite") {
+                out.with_component(Value::Object(o.clone()))
+            } else {
+                out
+            }
+        }
+        Value::Null => Text::empty(),
+    }
+}
+
+fn inline_object(
+    object: &serde_json::Map<String, Value>,
+    resolve: &mut dyn FnMut(&str) -> Text,
+    contents: &mut dyn FnMut(&serde_json::Map<String, Value>) -> Option<Text>,
+) -> Option<InlineObject> {
+    let kind = object.get("object").and_then(Value::as_str);
+    let fallback = object
+        .get("fallback")
+        .map(|value| to_text_with(value, resolve, contents).plain());
+    match kind {
+        Some("player") | None if object.contains_key("player") => {
+            let profile = object.get("player")?.clone();
+            // PlayerSprite.defaultFallback.
+            let fallback = fallback.unwrap_or_else(|| {
+                match profile
+                    .as_str()
+                    .or_else(|| profile.get("name").and_then(Value::as_str))
+                {
+                    Some(name) => format!("[{name} head]"),
+                    None => "[unknown player head]".to_owned(),
+                }
+            });
+            Some(InlineObject::Player {
+                profile,
+                hat: object.get("hat").and_then(Value::as_bool).unwrap_or(true),
+                fallback,
+            })
+        }
+        Some("atlas") | None if object.contains_key("sprite") => {
+            let atlas = object
+                .get("atlas")
+                .and_then(Value::as_str)
+                .unwrap_or("minecraft:blocks")
+                .to_owned();
+            let sprite = object.get("sprite")?.as_str()?.to_owned();
+            // AtlasSprite.defaultFallback: short names, the atlas unless blocks.
+            let fallback = fallback.unwrap_or_else(|| {
+                let short = |id: &str| match id.split_once(':') {
+                    Some(("minecraft", path)) => path.to_owned(),
+                    Some(_) => id.to_owned(),
+                    None => id.to_owned(),
+                };
+                if short(&atlas) == "blocks" {
+                    format!("[{}]", short(&sprite))
+                } else {
+                    format!("[{}@{}]", short(&sprite), short(&atlas))
+                }
+            });
+            Some(InlineObject::Atlas {
+                atlas,
+                sprite,
+                fallback,
+            })
+        }
+        _ => None,
+    }
+}
+
+/// `CustomName` as text: a string keeps its legacy formatting codes, anything
+/// else is a component (`ComponentSerialization`).
+pub fn name_text(tag: &Tag) -> Text {
+    match tag {
+        Tag::String(s) => Text::legacy(&s.to_string_lossy()),
+        t => crate::scoreboard::comp_text(&crate::scoreboard::tag_to_json(t)),
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    #[test]
+    fn shadow_color_accepts_packed_and_rgba_styles() {
+        let packed = serde_json::json!({"text": "A", "shadow_color": -16711936});
+        let text = to_text(&packed, &mut |_| Text::empty());
+        assert_eq!(text.spans[0].style.shadow_color, Some(0xff00ff00));
+        assert_eq!(text.component()["shadow_color"], -16711936);
+        let rgba = serde_json::json!({"text": "A", "shadow_color": [1, 0, 0.5, 1]});
+        let text = to_text(&rgba, &mut |_| Text::empty());
+        assert_eq!(text.spans[0].style.shadow_color, Some(0xffff007f));
+        let translucent = serde_json::json!({"text": "A", "shadow_color": [1, 0, 0.5, 0.5]});
+        let text = to_text(&translucent, &mut |_| Text::empty());
+        assert_eq!(text.spans[0].style.shadow_color, Some(0x7fff007f));
+        let no_shadow = serde_json::json!({"text": "A", "shadow_color": 0});
+        let text = to_text(&no_shadow, &mut |_| Text::empty());
+        assert_eq!(text.spans[0].style.shadow_color, Some(0));
+    }
+
+    #[test]
+    fn player_object_survives_text_parsing_and_keeps_its_siblings() {
+        let component = serde_json::json!({
+            "text": "<",
+            "extra": [
+                {"object": "player", "player": {"name": "elyapluggin"}, "hat": false,
+                 "fallback": "[head]"},
+                {"text": " >", "color": "gold"}
+            ]
+        });
+        let text = to_text(&component, &mut |_| Text::empty());
+        assert_eq!(text.plain(), "<[head] >");
+        assert!(matches!(
+            &text.spans[1].style.inline_object,
+            Some(InlineObject::Player { hat: false, .. })
+        ));
+        assert!(text.spans[2].style.inline_object.is_none());
+        assert_eq!(text.component(), component);
+        let sprite = serde_json::json!({"object": "atlas", "sprite": "minecraft:item/porkchop"});
+        let text = to_text(&sprite, &mut |_| Text::empty());
+        assert!(matches!(
+            &text.spans[0].style.inline_object,
+            Some(InlineObject::Atlas { sprite, .. }) if sprite == "minecraft:item/porkchop"
+        ));
+        // ObjectContents.visit without a fallback: the sprite's defaultFallback.
+        assert_eq!(text.plain(), "[item/porkchop]");
+        let head = serde_json::json!({"object": "player", "player": {"name": "Steve"}});
+        assert_eq!(
+            to_text(&head, &mut |_| Text::empty()).plain(),
+            "[Steve head]"
+        );
+        let gui = serde_json::json!({"atlas": "gui", "sprite": "hud/heart/full"});
+        assert_eq!(
+            to_text(&gui, &mut |_| Text::empty()).plain(),
+            "[hud/heart/full@gui]"
+        );
+    }
+
+    #[test]
+    fn snbt_and_json_components() {
+        let input = "{text:'Hi ',color:red,extra:[{text:\"there\",bold:1b}]} rest";
+        let (v, n) = parse_snbt(input).unwrap();
+        assert_eq!(&input[n..], " rest");
+        let t = to_text(&v, &mut |_| Text::empty());
+        assert_eq!(t.plain(), "Hi there");
+        assert_eq!(t.spans[1].style.color, named_color("red"));
+        let (v, _) = parse_snbt("[\"a\",{\"text\":\"b\"}]").unwrap();
+        assert_eq!(to_text(&v, &mut |_| Text::empty()).plain(), "ab");
+    }
+
+    #[test]
+    fn the_font_is_inherited_and_kept() {
+        let (v, _) =
+            parse_snbt(r#"{text:"a",font:"alt",extra:["b",{text:"c",font:"minecraft:uniform"}]}"#)
+                .unwrap();
+        let t = to_text(&v, &mut |_| Text::empty());
+        let fonts: Vec<_> = t.chars().map(|(_, s)| s.font.clone()).collect();
+        let (alt, uniform) = (
+            Some("minecraft:alt".into()),
+            Some("minecraft:uniform".into()),
+        );
+        assert_eq!(fonts, [alt.clone(), alt, uniform]);
+        // Back to JSON with the field, which a re-read keeps.
+        let again = to_text(&t.component(), &mut |_| Text::empty());
+        let kept: Vec<_> = again.chars().map(|(_, s)| s.font.clone()).collect();
+        assert_eq!(kept, fonts);
+        // Not an identifier: no font.
+        let (v, _) = parse_snbt(r#"{text:"a",font:"Bad Font"}"#).unwrap();
+        let t = to_text(&v, &mut |_| Text::empty());
+        assert_eq!(t.spans[0].style.font, None);
+    }
+
+    #[test]
+    fn snbt_nesting_is_bounded() {
+        let nest = |n: usize| format!("{}1{}", "[".repeat(n), "]".repeat(n));
+        assert!(parse_snbt(&nest(512)).is_ok());
+        assert!(parse_snbt(&nest(513)).is_err());
+        assert!(parse_snbt(&nest(100_000)).is_err());
+    }
+
+    #[test]
+    fn bare_words_that_look_numeric_stay_strings() {
+        let (v, _) = parse_snbt("{text:nan}").unwrap();
+        assert_eq!(v["text"], Value::String("nan".into()));
+        let (v, _) = parse_snbt("{text:Infinity}").unwrap();
+        assert_eq!(v["text"], Value::String("Infinity".into()));
+        let (v, _) = parse_snbt("{n:1.5}").unwrap();
+        assert_eq!(v["n"], Value::from(1.5));
+    }
+}

crates/horizon-client-core/src/gamerules.rs

@@ -292,27 +292,4 @@ mod tests {
         assert_eq!(GameRules::load(&dir), rules);
         let _ = fs::remove_dir_all(dir);
     }
-    /// The world's save (Level.write) writes the rules as they are now, and a
-    /// world opened again reads them back (#74).
-    #[test]
-    fn level_save_keeps_changed_rules() {
-        let dir =
-            std::env::temp_dir().join(format!("horizon-gamerules-level-{}", std::process::id()));
-        let _ = fs::remove_dir_all(&dir);
-        let mut level = crate::save::Level::default();
-        level.write(&dir).unwrap();
-        // Rules changed while playing, then saved and loaded again.
-        let mut rules = GameRules::load(&dir);
-        assert_eq!(rules, GameRules::default());
-        assert!(rules.set("advance_time", Value::Bool(false)));
-        assert!(rules.set("advance_weather", Value::Bool(false)));
-        assert!(rules.set("random_tick_speed", Value::Int(0)));
-        level.game_rules = rules.by_name();
-        level.write(&dir).unwrap();
-        assert_eq!(GameRules::load(&dir), rules);
-        let read = crate::save::Level::read(&dir).unwrap();
-        assert_eq!(read.game_rules, rules.by_name());
-        assert_eq!(read.game_rule("advance_time"), 0);
-        let _ = fs::remove_dir_all(dir);
-    }
 }

crates/horizon-client-core/src/identifier.rs

@@ -0,0 +1,35 @@
+//! Resource identifiers (`Identifier`).
+
+/// Identifier.parse: `ns:path` or `path`, validated.
+pub fn parse_identifier(raw: &str) -> Option<String> {
+    let (ns, path) = match raw.split_once(':') {
+        Some(("", path)) => ("minecraft", path),
+        Some((ns, path)) => (ns, path),
+        None => ("minecraft", raw),
+    };
+    let ns_ok = ns != ".."
+        && ns
+            .chars()
+            .all(|c| c.is_ascii_lowercase() || c.is_ascii_digit() || matches!(c, '_' | '.' | '-'));
+    let path_ok = path.chars().all(|c| {
+        c.is_ascii_lowercase() || c.is_ascii_digit() || matches!(c, '_' | '.' | '-' | '/')
+    });
+    (ns_ok && path_ok).then(|| format!("{ns}:{path}"))
+}
+
+/// `Identifier.CODEC` parsing an entity id: lowercase namespace and path
+/// characters, `minecraft` when the namespace is left out.
+pub fn normalize_id(s: &str) -> Option<String> {
+    let (ns, path) = match s.split_once(':') {
+        Some((ns, path)) => (if ns.is_empty() { "minecraft" } else { ns }, path),
+        None => ("minecraft", s),
+    };
+    let ok = |c: char, slash: bool| {
+        c.is_ascii_lowercase()
+            || c.is_ascii_digit()
+            || matches!(c, '_' | '-' | '.')
+            || slash && c == '/'
+    };
+    (ns.chars().all(|c| ok(c, false)) && path.chars().all(|c| ok(c, true)))
+        .then(|| format!("{ns}:{path}"))
+}

crates/horizon-client-core/src/key_display.rs

@@ -0,0 +1,38 @@
+//! Key display names (`InputConstants.Key.getDisplayName`), shared by key
+//! mappings and `keybind` text components.
+use crate::text::Text;
+
+/// InputConstants.Key.getDisplayName: one-character keys as the upper-case
+/// character, others by translation.
+pub fn display_name(key: &str) -> Text {
+    if let Some(rest) = key.strip_prefix("key.keyboard.")
+        && rest.chars().count() == 1
+    {
+        let c = rest.to_uppercase();
+        return Text::literal(c);
+    }
+    let symbol = match key {
+        "key.keyboard.minus" => Some("-"),
+        "key.keyboard.equal" => Some("="),
+        "key.keyboard.left.bracket" => Some("["),
+        "key.keyboard.right.bracket" => Some("]"),
+        "key.keyboard.backslash" => Some("\\"),
+        "key.keyboard.semicolon" => Some(";"),
+        "key.keyboard.apostrophe" => Some("'"),
+        "key.keyboard.grave.accent" => Some("`"),
+        "key.keyboard.comma" => Some(","),
+        "key.keyboard.period" => Some("."),
+        "key.keyboard.slash" => Some("/"),
+        _ => None,
+    };
+    if let Some(s) = symbol {
+        return Text::literal(s);
+    }
+    if let Some(n) = key.strip_prefix("key.mouse.")
+        && n.parse::<u32>().is_ok()
+        && !crate::lang::has(key)
+    {
+        return Text::translate("key.mouse", &[Text::literal(n)]);
+    }
+    Text::translate(key, &[])
+}

crates/horizon-client-core/src/lang.rs

@@ -4,7 +4,10 @@
 //! language used by every screen.
 use std::{
     collections::{BTreeMap, HashMap},
-    sync::{Arc, RwLock},
+    sync::{
+        Arc, RwLock,
+        atomic::{AtomicBool, Ordering},
+    },
 };
 
 #[derive(Clone, Debug, PartialEq, Eq)]
@@ -23,15 +26,24 @@ impl LanguageInfo {
 #[derive(Default)]
 pub struct Language {
     pub code: String,
+    /// `LanguageInfo.bidirectional`: text without a strong character reads
+    /// right to left (`ClientLanguage.defaultRightToLeft`).
+    bidirectional: bool,
     map: HashMap<String, String>,
 }
 pub const DEFAULT: &str = "en_us";
 
 static CURRENT: RwLock<Option<Arc<Language>>> = RwLock::new(None);
+/// The current language's `bidirectional`, read for every drawn string.
+static BIDIRECTIONAL: AtomicBool = AtomicBool::new(false);
 
 /// A source of resource files: the prepared root plus packs, highest priority last.
 pub trait ResourceSource {
     fn read(&self, path: &str) -> Option<Vec<u8>>;
+    /// Whether `path` is there, without reading it where the source can tell.
+    fn exists(&self, path: &str) -> bool {
+        self.read(path).is_some()
+    }
     /// The namespaces under `assets/` (resource packs may add their own).
     fn namespaces(&self) -> Vec<String> {
         vec!["minecraft".into()]
@@ -42,8 +54,18 @@ struct Bundled;
 impl ResourceSource for Bundled {
     fn read(&self, path: &str) -> Option<Vec<u8>> {
         let body = match path {
-            "assets/horizon/lang/en_us.json" => include_str!("../assets/horizon/lang/en_us.json"),
-            "assets/horizon/lang/ru_ru.json" => include_str!("../assets/horizon/lang/ru_ru.json"),
+            "assets/horizon/lang/en_us.json" => {
+                include_str!("../../horizon-client/assets/horizon/lang/en_us.json")
+            }
+            "assets/horizon/lang/ru_ru.json" => {
+                include_str!("../../horizon-client/assets/horizon/lang/ru_ru.json")
+            }
+            "assets/horizon/lang/pl_pl.json" => {
+                include_str!("../../horizon-client/assets/horizon/lang/pl_pl.json")
+            }
+            "assets/horizon/lang/uk_ua.json" => {
+                include_str!("../../horizon-client/assets/horizon/lang/uk_ua.json")
+            }
             _ => return None,
         };
         Some(body.as_bytes().to_vec())
@@ -56,6 +78,9 @@ impl ResourceSource for std::path::PathBuf {
     fn read(&self, path: &str) -> Option<Vec<u8>> {
         std::fs::read(self.join(path)).ok()
     }
+    fn exists(&self, path: &str) -> bool {
+        self.join(path).is_file()
+    }
     fn namespaces(&self) -> Vec<String> {
         std::fs::read_dir(self.join("assets"))
             .into_iter()
@@ -130,8 +155,12 @@ impl Language {
         {
             apply_deprecated(&mut map, &bytes);
         }
+        let bidirectional = available(sources)
+            .iter()
+            .any(|info| info.code == code && info.bidirectional);
         Self {
             code: code.to_owned(),
+            bidirectional,
             map,
         }
     }
@@ -174,7 +203,7 @@ pub fn available(sources: &[&dyn ResourceSource]) -> Vec<LanguageInfo> {
             for (code, info) in value["language"].as_object().into_iter().flatten() {
                 // Only languages whose file exists somewhere are selectable.
                 let file = format!("assets/minecraft/lang/{code}.json");
-                if code != DEFAULT && !sources.iter().any(|s| s.read(&file).is_some()) {
+                if code != DEFAULT && !sources.iter().any(|s| s.exists(&file)) {
                     continue;
                 }
                 found.insert(
@@ -193,11 +222,16 @@ pub fn available(sources: &[&dyn ResourceSource]) -> Vec<LanguageInfo> {
 }
 
 pub fn set(language: Language) {
+    BIDIRECTIONAL.store(language.bidirectional, Ordering::Relaxed);
     *CURRENT.write().unwrap_or_else(|e| e.into_inner()) = Some(Arc::new(language));
 }
 pub fn current() -> Option<Arc<Language>> {
     CURRENT.read().unwrap_or_else(|e| e.into_inner()).clone()
 }
+/// `ClientLanguage.defaultRightToLeft` of the current language.
+pub fn bidirectional() -> bool {
+    BIDIRECTIONAL.load(Ordering::Relaxed)
+}
 pub fn code() -> String {
     current().map_or_else(|| DEFAULT.to_owned(), |l| l.code.clone())
 }
@@ -238,6 +272,21 @@ mod tests {
         assert_eq!(en.get("horizon.options.controller"), Some("Controller"));
         let ru = Language::load(&[&empty], "ru_ru");
         assert_eq!(ru.get("horizon.options.controller"), Some("Геймпад"));
+        // Every bundled string carries both languages: a key added to one file
+        // and forgotten in the other shows as a key name on screen.
+        for key in en.map().keys() {
+            assert!(ru.get(key).is_some(), "{key} has no ru_ru value");
+        }
+        assert_eq!(en.get("horizon.pages.mods"), Some("Mods"));
+        assert_eq!(ru.get("horizon.pages.mods"), Some("Моды"));
+        let pl = Language::load(&[&empty], "pl_pl");
+        assert_eq!(pl.get("horizon.options.controller"), Some("Kontroler"));
+        assert_eq!(pl.get("horizon.options.vibration"), Some("Wibracje"));
+        let uk = Language::load(&[&empty], "uk_ua");
+        assert_eq!(
+            uk.get("horizon.options.on_screen_keyboard"),
+            Some("Екранна клавіатура")
+        );
     }
 
     #[test]
@@ -263,4 +312,26 @@ mod tests {
         );
         assert_eq!(langs[1].label(), "Français (France)");
     }
+
+    #[test]
+    fn languages_are_listed_without_reading_their_files() {
+        struct NoLangReads;
+        impl ResourceSource for NoLangReads {
+            fn read(&self, path: &str) -> Option<Vec<u8>> {
+                assert!(!path.contains("/lang/"), "read {path}");
+                (path == "assets/pack.mcmeta").then(|| {
+                    br#"{"language":{"fr_fr":{"name":"French"},"de_de":{"name":"German"}}}"#
+                        .to_vec()
+                })
+            }
+            fn exists(&self, path: &str) -> bool {
+                path == "assets/minecraft/lang/fr_fr.json"
+            }
+        }
+        let langs = available(&[&NoLangReads]);
+        assert_eq!(
+            langs.iter().map(|l| l.code.as_str()).collect::<Vec<_>>(),
+            ["en_us", "fr_fr"]
+        );
+    }
 }

crates/horizon-client-core/src/lib.rs

@@ -0,0 +1,28 @@
+//! The client's lowest layer, below commands and gameplay: chat text and
+//! translations, SNBT and NBT paths, text components, the scoreboard, boss
+//! bars, game rules, block entity NBT tables, and the registry, particle and
+//! sound source tables commands name, and the `pack.mcmeta` filter regex.
+//! horizon-client re-exports each module under its old path
+//! (`horizon_client::text`, ...).
+#![forbid(unsafe_code)]
+pub mod block_entity_nbt;
+pub mod bossbar;
+pub mod component;
+pub mod fastutil_order;
+pub mod gamerules;
+pub mod identifier;
+pub mod key_display;
+pub mod lang;
+pub mod nbt_path;
+pub mod nbt_value;
+pub mod particle_type;
+pub mod pattern;
+pub mod potions;
+pub mod registries;
+pub mod scoreboard;
+pub mod snbt;
+pub mod sound_source;
+pub mod text;
+pub mod uuid;
+pub mod who;
+pub type Result<T> = std::result::Result<T, Box<dyn std::error::Error>>;

crates/horizon-client-core/src/nbt_value.rs

@@ -0,0 +1,32 @@
+//! Reading and writing single NBT values the way vanilla's codecs accept them.
+use horizon_world::nbt::Tag;
+
+pub fn string(s: &str) -> Tag {
+    Tag::String(s.into())
+}
+pub fn text(tag: Option<&Tag>) -> Option<String> {
+    match tag {
+        Some(Tag::String(s)) => Some(s.to_string_lossy()),
+        _ => None,
+    }
+}
+/// Any numeric tag as i64 (vanilla's `getIntOr` etc. accept every number type).
+pub fn number(tag: Option<&Tag>) -> Option<i64> {
+    Some(match tag? {
+        Tag::Byte(v) => i64::from(*v),
+        Tag::Short(v) => i64::from(*v),
+        Tag::Int(v) => i64::from(*v),
+        Tag::Long(v) => *v,
+        Tag::Float(b) => f32::from_bits(*b) as i64,
+        Tag::Double(b) => f64::from_bits(*b) as i64,
+        _ => return None,
+    })
+}
+/// Any numeric tag as f64, keeping a float's or double's fraction.
+pub fn float(tag: Option<&Tag>) -> Option<f64> {
+    Some(match tag? {
+        Tag::Float(b) => f64::from(f32::from_bits(*b)),
+        Tag::Double(b) => f64::from_bits(*b),
+        other => number(Some(other))? as f64,
+    })
+}

crates/horizon-client-core/src/particle_type.rs

@@ -0,0 +1,221 @@
+//! Particle types (`ParticleTypes`): the vanilla particle types with a client
+//! implementation, by registry name, and their per-type flags.
+
+macro_rules! particle_types {
+    ($($variant:ident = $name:literal),* $(,)?) => {
+        /// Vanilla particle types with a client implementation here.
+        #[derive(Clone, Copy, Debug, PartialEq, Eq, Hash)]
+        pub enum ParticleType { $($variant),* }
+        impl ParticleType {
+            pub const ALL: &'static [ParticleType] = &[$(ParticleType::$variant),*];
+            /// Registry path (`minecraft:<name>`), also the sprite-set file name.
+            pub fn name(self) -> &'static str {
+                match self { $(ParticleType::$variant => $name),* }
+            }
+            pub fn from_name(name: &str) -> Option<Self> {
+                let name = name.strip_prefix("minecraft:").unwrap_or(name);
+                match name { $($name => Some(ParticleType::$variant),)* _ => None }
+            }
+        }
+    };
+}
+particle_types! {
+    Block = "block",
+    BlockCrumble = "block_crumble",
+    Trail = "trail",
+    DustPillar = "dust_pillar",
+    FallingDust = "falling_dust",
+    Smoke = "smoke",
+    LargeSmoke = "large_smoke",
+    WhiteSmoke = "white_smoke",
+    Flame = "flame",
+    SoulFireFlame = "soul_fire_flame",
+    CopperFireFlame = "copper_fire_flame",
+    SmallFlame = "small_flame",
+    Lava = "lava",
+    DrippingWater = "dripping_water",
+    FallingWater = "falling_water",
+    DrippingLava = "dripping_lava",
+    FallingLava = "falling_lava",
+    LandingLava = "landing_lava",
+    DrippingHoney = "dripping_honey",
+    FallingHoney = "falling_honey",
+    LandingHoney = "landing_honey",
+    FallingNectar = "falling_nectar",
+    FallingSporeBlossom = "falling_spore_blossom",
+    SporeBlossomAir = "spore_blossom_air",
+    DrippingObsidianTear = "dripping_obsidian_tear",
+    FallingObsidianTear = "falling_obsidian_tear",
+    LandingObsidianTear = "landing_obsidian_tear",
+    DrippingDripstoneWater = "dripping_dripstone_water",
+    FallingDripstoneWater = "falling_dripstone_water",
+    DrippingDripstoneLava = "dripping_dripstone_lava",
+    FallingDripstoneLava = "falling_dripstone_lava",
+    Splash = "splash",
+    Rain = "rain",
+    Bubble = "bubble",
+    SulfurBubbles = "sulfur_bubbles",
+    NoxiousGas = "noxious_gas",
+    NoxiousGasCloud = "noxious_gas_cloud",
+    Geyser = "geyser",
+    GeyserBase = "geyser_base",
+    GeyserPoof = "geyser_poof",
+    GeyserPlume = "geyser_plume",
+    BubblePop = "bubble_pop",
+    BubbleColumnUp = "bubble_column_up",
+    CurrentDown = "current_down",
+    Underwater = "underwater",
+    Portal = "portal",
+    ReversePortal = "reverse_portal",
+    Enchant = "enchant",
+    Nautilus = "nautilus",
+    VaultConnection = "vault_connection",
+    Crit = "crit",
+    EnchantedHit = "enchanted_hit",
+    DamageIndicator = "damage_indicator",
+    Heart = "heart",
+    AngryVillager = "angry_villager",
+    HappyVillager = "happy_villager",
+    Composter = "composter",
+    Mycelium = "mycelium",
+    Dolphin = "dolphin",
+    EggCrack = "egg_crack",
+    Poof = "poof",
+    Explosion = "explosion",
+    ExplosionEmitter = "explosion_emitter",
+    CampfireCosySmoke = "campfire_cosy_smoke",
+    CampfireSignalSmoke = "campfire_signal_smoke",
+    Note = "note",
+    Dust = "dust",
+    TotemOfUndying = "totem_of_undying",
+    Firework = "firework",
+    EndRod = "end_rod",
+    Ash = "ash",
+    WhiteAsh = "white_ash",
+    CrimsonSpore = "crimson_spore",
+    WarpedSpore = "warped_spore",
+    CherryLeaves = "cherry_leaves",
+    PaleOakLeaves = "pale_oak_leaves",
+    TintedLeaves = "tinted_leaves",
+    Effect = "effect",
+    InstantEffect = "instant_effect",
+    EntityEffect = "entity_effect",
+    Witch = "witch",
+    Infested = "infested",
+    Cloud = "cloud",
+    Sneeze = "sneeze",
+    Snowflake = "snowflake",
+    Soul = "soul",
+    SculkSoul = "sculk_soul",
+    DragonBreath = "dragon_breath",
+    Gust = "gust",
+    SmallGust = "small_gust",
+    GustEmitterLarge = "gust_emitter_large",
+    GustEmitterSmall = "gust_emitter_small",
+    DustColorTransition = "dust_color_transition",
+    SculkCharge = "sculk_charge",
+    SculkChargePop = "sculk_charge_pop",
+    Shriek = "shriek",
+    SonicBoom = "sonic_boom",
+    Vibration = "vibration",
+    SweepAttack = "sweep_attack",
+    Glow = "glow",
+    WaxOn = "wax_on",
+    WaxOff = "wax_off",
+    ElectricSpark = "electric_spark",
+    Scrape = "scrape",
+    SquidInk = "squid_ink",
+    GlowSquidInk = "glow_squid_ink",
+    Item = "item",
+    ItemSlime = "item_slime",
+    ItemSnowball = "item_snowball",
+    ItemCobweb = "item_cobweb",
+    SulfurCubeGoo = "sulfur_cube_goo",
+    Flash = "flash",
+    Firefly = "firefly",
+    TrialSpawnerDetection = "trial_spawner_detection",
+    TrialSpawnerDetectionOminous = "trial_spawner_detection_ominous",
+    TrialOmen = "trial_omen",
+    RaidOmen = "raid_omen",
+    OminousSpawning = "ominous_spawning",
+    Spit = "spit",
+    Fishing = "fishing",
+    DustPlume = "dust_plume",
+    RedPoplarLeaves = "red_poplar_leaves",
+    OrangePoplarLeaves = "orange_poplar_leaves",
+    YellowPoplarLeaves = "yellow_poplar_leaves",
+    PauseMobGrowth = "pause_mob_growth",
+    ResetMobGrowth = "reset_mob_growth",
+    BlockMarker = "block_marker",
+}
+impl ParticleType {
+    /// `ParticleType.getOverrideLimiter` (`ParticleTypes.register(name, true)`):
+    /// spawned regardless of distance.
+    pub fn override_limiter(self) -> bool {
+        matches!(
+            self,
+            Self::BlockMarker
+                | Self::Geyser
+                | Self::GeyserBase
+                | Self::GeyserPoof
+                | Self::GeyserPlume
+                | Self::DamageIndicator
+                | Self::ExplosionEmitter
+                | Self::Explosion
+                | Self::Gust
+                | Self::GustEmitterLarge
+                | Self::GustEmitterSmall
+                | Self::SonicBoom
+                | Self::SculkCharge
+                | Self::SculkChargePop
+                | Self::Vibration
+                | Self::Poof
+                | Self::Spit
+                | Self::SquidInk
+                | Self::SweepAttack
+                | Self::CampfireCosySmoke
+                | Self::CampfireSignalSmoke
+                | Self::GlowSquidInk
+                | Self::Glow
+                | Self::WaxOn
+                | Self::WaxOff
+                | Self::ElectricSpark
+                | Self::Scrape
+                | Self::TrialSpawnerDetection
+                | Self::TrialSpawnerDetectionOminous
+                | Self::VaultConnection
+                | Self::OminousSpawning
+        )
+    }
+    /// `SingleQuadParticle.Layer.translucent`: types whose vanilla particle class
+    /// hardcodes the translucent layer, drawn after translucent terrain.
+    /// `TerrainParticle`, `BreakingItemParticle` and `BlockMarker` resolve their
+    /// layer from the sprite instead (`Layer.bySprite`); see the `translucent`
+    /// sprite set on the engine.
+    pub fn translucent_layer(self) -> bool {
+        match self {
+            // CampfireSmokeParticle.
+            Self::CampfireCosySmoke | Self::CampfireSignalSmoke
+            // PlayerCloudParticle.
+            | Self::Cloud | Self::Sneeze
+            // SpellParticle.
+            | Self::Effect | Self::InstantEffect | Self::EntityEffect
+            | Self::Witch | Self::Infested | Self::TrialOmen | Self::RaidOmen
+            // NoxiousGasParticle.
+            | Self::NoxiousGas
+            // EmissiveRisingParticle.
+            | Self::Soul | Self::SculkSoul
+            // SculkChargeParticle, SculkChargePopParticle, ShriekParticle,
+            // VibrationSignalParticle, FireflyParticle, OverlayParticle.
+            | Self::SculkCharge | Self::SculkChargePop | Self::Shriek
+            | Self::Vibration | Self::Firefly | Self::Flash
+            // SimpleAnimatedParticle and its subclasses: EndRodParticle,
+            // SparkParticle (firework), SquidInkParticle, TotemParticle.
+            | Self::EndRod | Self::Firework | Self::SquidInk | Self::GlowSquidInk
+            | Self::TotemOfUndying
+            // FlyTowardsPositionParticle: its LifetimeAlpha(0, 0.6, 0.25, 1) is not opaque.
+            | Self::VaultConnection => true,
+            _ => false,
+        }
+    }
+}

crates/horizon-client-core/src/potions.rs

@@ -0,0 +1,250 @@
+//! The `MobEffects` and `Potions` registries (code in vanilla, ported as
+//! tables): each effect's colour and category, each potion's effects, and the
+//! potion colour mix. horizon-client re-exports them from `brewing`.
+use std::{collections::HashMap, sync::OnceLock};
+
+#[derive(Clone, Copy, Debug, PartialEq, Eq)]
+pub enum Category {
+    Beneficial,
+    Harmful,
+    Neutral,
+}
+/// A `MobEffect`: id (without namespace), colour, category, instantaneous.
+#[derive(Clone, Copy, Debug)]
+pub struct EffectDef {
+    pub id: &'static str,
+    pub color: u32,
+    pub category: Category,
+    pub instant: bool,
+}
+const fn fx(id: &'static str, color: u32, category: Category) -> EffectDef {
+    EffectDef {
+        id,
+        color,
+        category,
+        instant: false,
+    }
+}
+use Category::{Beneficial as B, Harmful as H, Neutral as N};
+/// `MobEffects` in registration order.
+pub const EFFECTS: &[EffectDef] = &[
+    fx("speed", 3402751, B),
+    fx("slowness", 9154528, H),
+    fx("haste", 14270531, B),
+    fx("mining_fatigue", 4866583, H),
+    fx("strength", 16762624, B),
+    EffectDef {
+        id: "instant_health",
+        color: 16262179,
+        category: B,
+        instant: true,
+    },
+    EffectDef {
+        id: "instant_damage",
+        color: 11101546,
+        category: H,
+        instant: true,
+    },
+    fx("jump_boost", 16646020, B),
+    fx("nausea", 5578058, H),
+    fx("regeneration", 13458603, B),
+    fx("resistance", 9520880, B),
+    fx("fire_resistance", 16750848, B),
+    fx("water_breathing", 10017472, B),
+    fx("invisibility", 16185078, B),
+    fx("blindness", 2039587, H),
+    fx("night_vision", 12779366, B),
+    fx("hunger", 5797459, H),
+    fx("weakness", 4738376, H),
+    fx("poison", 8889187, H),
+    fx("wither", 7561558, H),
+    fx("health_boost", 16284963, B),
+    fx("absorption", 2445989, B),
+    EffectDef {
+        id: "saturation",
+        color: 16262179,
+        category: B,
+        instant: true,
+    },
+    fx("glowing", 9740385, N),
+    fx("levitation", 13565951, H),
+    fx("luck", 5882118, B),
+    fx("unluck", 12624973, H),
+    fx("slow_falling", 15978425, B),
+    fx("conduit_power", 1950417, B),
+    fx("dolphins_grace", 8954814, B),
+    fx("bad_omen", 745784, N),
+    fx("hero_of_the_village", 4521796, B),
+    fx("darkness", 2696993, H),
+    fx("trial_omen", 1484454, N),
+    fx("raid_omen", 14565464, N),
+    fx("wind_charged", 12438015, H),
+    fx("weaving", 7891290, H),
+    fx("oozing", 10092451, H),
+    fx("infested", 9214860, H),
+    fx("breath_of_the_nautilus", 65518, B),
+];
+pub fn effect(id: &str) -> Option<&'static EffectDef> {
+    let id = id.trim_start_matches("minecraft:");
+    EFFECTS.iter().find(|e| e.id == id)
+}
+/// Namespaced effect ids for mob effect storage.
+pub fn namespaced(id: &'static str) -> &'static str {
+    static IDS: OnceLock<HashMap<&'static str, &'static str>> = OnceLock::new();
+    let key = id.strip_prefix("minecraft:").unwrap_or(id);
+    IDS.get_or_init(|| {
+        EFFECTS
+            .iter()
+            .map(|e| {
+                (
+                    e.id,
+                    &*Box::leak(format!("minecraft:{}", e.id).into_boxed_str()),
+                )
+            })
+            .collect()
+    })
+    .get(key)
+    .copied()
+    .unwrap_or(id)
+}
+/// A `Potion`: id, name suffix (`item.minecraft.potion.effect.<name>`) and
+/// effects as (effect, duration ticks, amplifier).
+#[derive(Clone, Copy, Debug)]
+pub struct PotionDef {
+    pub id: &'static str,
+    pub name: &'static str,
+    pub effects: &'static [(&'static str, i32, i32)],
+}
+const fn p(
+    id: &'static str,
+    name: &'static str,
+    effects: &'static [(&'static str, i32, i32)],
+) -> PotionDef {
+    PotionDef { id, name, effects }
+}
+/// `Potions` in registration order.
+pub const POTIONS: &[PotionDef] = &[
+    p("water", "water", &[]),
+    p("mundane", "mundane", &[]),
+    p("thick", "thick", &[]),
+    p("awkward", "awkward", &[]),
+    p("night_vision", "night_vision", &[("night_vision", 3600, 0)]),
+    p(
+        "long_night_vision",
+        "night_vision",
+        &[("night_vision", 9600, 0)],
+    ),
+    p("invisibility", "invisibility", &[("invisibility", 3600, 0)]),
+    p(
+        "long_invisibility",
+        "invisibility",
+        &[("invisibility", 9600, 0)],
+    ),
+    p("leaping", "leaping", &[("jump_boost", 3600, 0)]),
+    p("long_leaping", "leaping", &[("jump_boost", 9600, 0)]),
+    p("strong_leaping", "leaping", &[("jump_boost", 1800, 1)]),
+    p(
+        "fire_resistance",
+        "fire_resistance",
+        &[("fire_resistance", 3600, 0)],
+    ),
+    p(
+        "long_fire_resistance",
+        "fire_resistance",
+        &[("fire_resistance", 9600, 0)],
+    ),
+    p("swiftness", "swiftness", &[("speed", 3600, 0)]),
+    p("long_swiftness", "swiftness", &[("speed", 9600, 0)]),
+    p("strong_swiftness", "swiftness", &[("speed", 1800, 1)]),
+    p("slowness", "slowness", &[("slowness", 1800, 0)]),
+    p("long_slowness", "slowness", &[("slowness", 4800, 0)]),
+    p("strong_slowness", "slowness", &[("slowness", 400, 3)]),
+    p(
+        "turtle_master",
+        "turtle_master",
+        &[("slowness", 400, 3), ("resistance", 400, 2)],
+    ),
+    p(
+        "long_turtle_master",
+        "turtle_master",
+        &[("slowness", 800, 3), ("resistance", 800, 2)],
+    ),
+    p(
+        "strong_turtle_master",
+        "turtle_master",
+        &[("slowness", 400, 5), ("resistance", 400, 3)],
+    ),
+    p(
+        "water_breathing",
+        "water_breathing",
+        &[("water_breathing", 3600, 0)],
+    ),
+    p(
+        "long_water_breathing",
+        "water_breathing",
+        &[("water_breathing", 9600, 0)],
+    ),
+    p("healing", "healing", &[("instant_health", 1, 0)]),
+    p("strong_healing", "healing", &[("instant_health", 1, 1)]),
+    p("harming", "harming", &[("instant_damage", 1, 0)]),
+    p("strong_harming", "harming", &[("instant_damage", 1, 1)]),
+    p("poison", "poison", &[("poison", 900, 0)]),
+    p("long_poison", "poison", &[("poison", 1800, 0)]),
+    p("strong_poison", "poison", &[("poison", 432, 1)]),
+    p("regeneration", "regeneration", &[("regeneration", 900, 0)]),
+    p(
+        "long_regeneration",
+        "regeneration",
+        &[("regeneration", 1800, 0)],
+    ),
+    p(
+        "strong_regeneration",
+        "regeneration",
+        &[("regeneration", 450, 1)],
+    ),
+    p("strength", "strength", &[("strength", 3600, 0)]),
+    p("long_strength", "strength", &[("strength", 9600, 0)]),
+    p("strong_strength", "strength", &[("strength", 1800, 1)]),
+    p("weakness", "weakness", &[("weakness", 1800, 0)]),
+    p("long_weakness", "weakness", &[("weakness", 4800, 0)]),
+    p("luck", "luck", &[("luck", 6000, 0)]),
+    p("slow_falling", "slow_falling", &[("slow_falling", 1800, 0)]),
+    p(
+        "long_slow_falling",
+        "slow_falling",
+        &[("slow_falling", 4800, 0)],
+    ),
+    p("wind_charged", "wind_charged", &[("wind_charged", 3600, 0)]),
+    p("weaving", "weaving", &[("weaving", 3600, 0)]),
+    p("oozing", "oozing", &[("oozing", 3600, 0)]),
+    p("infested", "infested", &[("infested", 3600, 0)]),
+];
+pub fn potion(id: &str) -> Option<&'static PotionDef> {
+    let id = id.trim_start_matches("minecraft:");
+    POTIONS.iter().find(|p| p.id == id)
+}
+/// `PotionContents.BASE_POTION_COLOR` (ARGB -13083194) as RGB.
+pub const BASE_POTION_COLOR: u32 = 0x385DC6;
+/// `PotionContents.getColor`: amplifier-weighted mix of visible effect colours.
+pub fn potion_color(id: Option<&str>) -> u32 {
+    let Some(def) = id.and_then(potion) else {
+        return BASE_POTION_COLOR;
+    };
+    let (mut r, mut g, mut b, mut total) = (0u32, 0u32, 0u32, 0u32);
+    for (e, _, amp) in def.effects {
+        let Some(e) = effect(e) else { continue };
+        let w = *amp as u32 + 1;
+        r += w * (e.color >> 16 & 255);
+        g += w * (e.color >> 8 & 255);
+        b += w * (e.color & 255);
+        total += w;
+    }
+    match (
+        r.checked_div(total),
+        g.checked_div(total),
+        b.checked_div(total),
+    ) {
+        (Some(r), Some(g), Some(b)) => (r << 16) | (g << 8) | b,
+        _ => BASE_POTION_COLOR,
+    }
+}

crates/horizon-client-core/src/registries.rs

@@ -0,0 +1,194 @@
+//! Registry contents and source state that commands validate and complete
+//! arguments against (what the server's registry access holds).
+use std::collections::BTreeMap;
+
+/// Registry contents and source state used to validate and complete arguments.
+#[derive(Clone, Debug, Default)]
+pub struct Registries {
+    /// Permission level of the command source.
+    pub permission: u8,
+    pub items: Vec<String>,
+    pub item_tags: Vec<String>,
+    /// Block id -> (property, allowed values).
+    pub blocks: BTreeMap<String, Vec<(String, Vec<String>)>>,
+    pub block_tags: Vec<String>,
+    /// Entity types that `summon` can create.
+    pub summonable: Vec<String>,
+    /// Every entity type (selector `type=`).
+    pub entity_types: Vec<String>,
+    pub effects: Vec<String>,
+    pub enchantments: Vec<String>,
+    pub structures: Vec<String>,
+    pub biomes: Vec<String>,
+    pub dimensions: Vec<String>,
+    pub clocks: Vec<String>,
+    pub timelines: Vec<String>,
+    pub time_markers: Vec<String>,
+    pub advancements: Vec<String>,
+    /// Game rule name -> integer-valued.
+    pub game_rules: Vec<(String, bool)>,
+    pub players: Vec<String>,
+    /// Scoreboard objective names, team names and tracked score holders.
+    pub objectives: Vec<String>,
+    pub teams: Vec<String>,
+    pub tracked: Vec<String>,
+    /// Loaded datapack functions (`ns:path`) and function tags (`ns:path`).
+    pub functions: Vec<String>,
+    /// `/data ... storage` ids.
+    pub storages: Vec<String>,
+    /// Boss bar ids and datapack predicate ids.
+    pub bossbars: Vec<String>,
+    pub predicates: Vec<String>,
+    pub item_modifiers: Vec<String>,
+    pub schedules: Vec<String>,
+    pub stopwatches: Vec<String>,
+    pub recipes: Vec<String>,
+    pub sounds: Vec<String>,
+    pub damage_types: Vec<String>,
+    pub attributes: Vec<String>,
+    pub loot_tables: Vec<String>,
+    pub templates: Vec<String>,
+    pub random_sequences: Vec<String>,
+    pub datapacks_enabled: Vec<String>,
+    pub datapacks_disabled: Vec<String>,
+    pub function_tags: Vec<String>,
+    /// The block the source is looking at (relevant coordinates).
+    pub target_block: Option<[i32; 3]>,
+    /// `ClientSuggestionProvider.getSelectedEntities`: the UUID of the
+    /// entity under the crosshair (`Entity.getStringUUID`), if any.
+    pub selected_entities: Vec<String>,
+    /// `ClientSuggestionProvider.getAbsoluteCoordinates`: the exact point of
+    /// that block hit, each coordinate as `%.2f` (`Locale.ROOT`).
+    pub target_point: Option<[String; 3]>,
+    /// Every registry's element and tag ids (`minecraft:item` -> ...), as
+    /// the server's registry access and reloadable registries hold them.
+    pub by_registry: BTreeMap<String, RegistryIds>,
+    /// Blocks whose default state has a block entity.
+    pub block_entities: std::collections::BTreeSet<String>,
+    /// Block tag -> member blocks.
+    pub block_tag_members: BTreeMap<String, Vec<String>>,
+    /// Data component types with a codec (not transient).
+    pub persistent_components: Vec<String>,
+    /// Recipes `/recipe` can give (not special).
+    pub learnable_recipes: Vec<String>,
+    /// Advancement id -> criterion names.
+    pub advancement_criteria: BTreeMap<String, Vec<String>>,
+    /// World clock -> time markers shown in commands.
+    pub clock_time_markers: BTreeMap<String, Vec<String>>,
+    /// Trigger objectives the source may use (`/trigger` suggestions).
+    pub trigger_objectives: Vec<String>,
+    /// Objectives with the `trigger` criterion -> holder -> whether its score is locked.
+    pub trigger_scores: BTreeMap<String, BTreeMap<String, bool>>,
+}
+/// The ids and tag ids of one registry.
+#[derive(Clone, Debug, Default)]
+pub struct RegistryIds {
+    pub ids: Vec<String>,
+    pub tags: Vec<String>,
+}
+const EMPTY: &[String] = &[];
+impl Registries {
+    /// Fill what the game did not build itself from vanilla's exported
+    /// registries (`command-registries.json`, written by
+    /// `VanillaCommandParseOracle registries`): built-in registries such as
+    /// mob effects, data component types and dialogs, block entities and tag
+    /// members. Registries that data packs reload stay with the game.
+    pub fn fill_from_export(&mut self, r: &serde_json::Value) {
+        fn strings(v: &serde_json::Value) -> Vec<String> {
+            v.as_array()
+                .map(|a| {
+                    a.iter()
+                        .filter_map(|x| x.as_str().map(str::to_owned))
+                        .collect()
+                })
+                .unwrap_or_default()
+        }
+        let fill = |field: &mut Vec<String>, key: &str| {
+            if field.is_empty() {
+                *field = strings(&r[key]);
+            }
+        };
+        fill(&mut self.effects, "effects");
+        fill(&mut self.enchantments, "enchantments");
+        fill(&mut self.attributes, "attributes");
+        fill(&mut self.damage_types, "damage_types");
+        fill(&mut self.templates, "templates");
+        fill(&mut self.persistent_components, "persistent_components");
+        fill(&mut self.learnable_recipes, "learnable_recipes");
+        const RELOADED: [&str; 5] = [
+            "minecraft:advancement",
+            "minecraft:recipe",
+            "minecraft:loot_table",
+            "minecraft:predicate",
+            "minecraft:item_modifier",
+        ];
+        for (name, entry) in r["by_registry"].as_object().into_iter().flatten() {
+            if RELOADED.contains(&name.as_str()) || self.by_registry.contains_key(name) {
+                continue;
+            }
+            self.by_registry.insert(
+                name.clone(),
+                RegistryIds {
+                    ids: strings(&entry["ids"]),
+                    tags: strings(&entry["tags"]),
+                },
+            );
+        }
+        if self.block_entities.is_empty() {
+            self.block_entities = strings(&r["block_entities"]).into_iter().collect();
+        }
+        if self.block_tag_members.is_empty() {
+            for (tag, members) in r["block_tag_members"].as_object().into_iter().flatten() {
+                self.block_tag_members.insert(tag.clone(), strings(members));
+            }
+        }
+        if self.clock_time_markers.is_empty() {
+            for (clock, markers) in r["clock_time_markers"].as_object().into_iter().flatten() {
+                self.clock_time_markers
+                    .insert(clock.clone(), strings(markers));
+            }
+        }
+        if self.advancement_criteria.is_empty() {
+            for (id, criteria) in r["advancement_criteria"].as_object().into_iter().flatten() {
+                self.advancement_criteria
+                    .insert(id.clone(), strings(criteria));
+            }
+        }
+    }
+    /// The element ids of a registry (sorted).
+    pub fn ids(&self, registry: &str) -> &[String] {
+        if let Some(r) = self.by_registry.get(registry) {
+            return &r.ids;
+        }
+        match registry {
+            "minecraft:item" => &self.items,
+            "minecraft:entity_type" => &self.entity_types,
+            "minecraft:mob_effect" => &self.effects,
+            "minecraft:enchantment" => &self.enchantments,
+            "minecraft:worldgen/structure" => &self.structures,
+            "minecraft:worldgen/biome" => &self.biomes,
+            "minecraft:world_clock" => &self.clocks,
+            "minecraft:timeline" => &self.timelines,
+            "minecraft:attribute" => &self.attributes,
+            "minecraft:damage_type" => &self.damage_types,
+            "minecraft:sound_event" => &self.sounds,
+            "minecraft:predicate" => &self.predicates,
+            "minecraft:item_modifier" => &self.item_modifiers,
+            "minecraft:loot_table" => &self.loot_tables,
+            "minecraft:recipe" => &self.recipes,
+            "minecraft:advancement" => &self.advancements,
+            _ => EMPTY,
+        }
+    }
+    /// The tag ids of a registry (sorted).
+    pub fn tags(&self, registry: &str) -> &[String] {
+        if let Some(r) = self.by_registry.get(registry) {
+            return &r.tags;
+        }
+        match registry {
+            "minecraft:item" => &self.item_tags,
+            "minecraft:block" => &self.block_tags,
+            _ => EMPTY,
+        }
+    }
+}

crates/horizon-client-core/src/scoreboard.rs

@@ -2,9 +2,9 @@
 //! `ObjectiveCriteria`, `NumberFormat`) and its saved data
 //! (`data/minecraft/scoreboard.dat`, `ScoreboardSaveData.Packed`).
 use crate::{
-    command::Registries,
     component,
     fastutil_order::{HashSetOrder, OpenOrder},
+    registries::Registries,
     text::{self, Style, Text},
 };
 use horizon_world::nbt::Tag;
@@ -112,6 +112,7 @@ pub fn style_from_json(v: &Value) -> Style {
                 .and_then(|h| u32::from_str_radix(h, 16).ok())
         });
     }
+    s.shadow_color = o.get("shadow_color").and_then(component::shadow_color);
     let flag = |k: &str| o.get(k).and_then(Value::as_bool);
     s.bold = flag("bold");
     s.italic = flag("italic");
@@ -662,10 +663,22 @@ pub fn name_shown(own: Option<&Team>, viewer: Option<&Team>, v: NameView) -> boo
     }
     !v.hud_hidden && !v.is_camera && visible && !v.is_vehicle
 }
-/// `ServerPlayer.die`: whether a player's death message reaches the player
-/// themselves (the team broadcasts leave out the dying player).
-pub fn own_death_message_shown(team: Option<&Team>) -> bool {
-    team.is_none_or(|t| t.death_message_visibility == Visibility::Always)
+/// `ServerPlayer.die`: whether `other` hears the death message of `dying`
+/// (`broadcastSystemMessage`, `broadcastSystemToTeam` or
+/// `broadcastSystemToAllExceptTeam`, by the team's death message visibility).
+pub fn death_message_reaches(board: &Scoreboard, dying: &str, other: &str) -> bool {
+    let Some(team) = board.players_team(dying) else {
+        return true;
+    };
+    let same_team = board
+        .players_team(other)
+        .is_some_and(|t| t.name == team.name);
+    match team.death_message_visibility {
+        Visibility::Always => true,
+        Visibility::Never => false,
+        Visibility::HideForOtherTeams => same_team && other != dying,
+        Visibility::HideForOwnTeam => !same_team,
+    }
 }
 
 // ---- objectives and scores ---------------------------------------------
@@ -1266,7 +1279,7 @@ fn entity_uuids(tag: &mut Tag) {
                             })
                             .collect::<Option<Vec<i32>>>(),
                         Tag::String(s) => {
-                            crate::save::uuid_from_text(&s.to_string_lossy()).map(Vec::from)
+                            crate::uuid::uuid_from_text(&s.to_string_lossy()).map(Vec::from)
                         }
                         _ => None,
                     };
@@ -1551,3 +1564,49 @@ mod tests {
         );
     }
 }
+
+/// `DamageSource.getLocalizedDeathMessage`: the cause's item with a custom
+/// name gets the `<id>.item` message, with the item's name as a third
+/// argument.
+pub fn death_message_args(
+    key: &str,
+    victim: &Text,
+    cause: &Text,
+    item: Option<&Text>,
+) -> (String, Vec<Text>) {
+    match item {
+        Some(item) => (
+            format!("{key}.item"),
+            vec![victim.clone(), cause.clone(), item.clone()],
+        ),
+        None => (key.to_owned(), vec![victim.clone(), cause.clone()]),
+    }
+}
+
+#[cfg(test)]
+mod death_message_tests {
+    use super::*;
+
+    #[test]
+    fn the_death_message_names_the_causes_item_when_it_has_a_custom_name() {
+        let victim = Text::literal("Steve");
+        let cause = Text::literal("Zombie");
+        // DamageSource.getLocalizedDeathMessage: the item variant, with the
+        // item's name as the third argument.
+        let (key, args) = death_message_args(
+            "death.attack.arrow",
+            &victim,
+            &cause,
+            Some(&Text::literal("My Sword")),
+        );
+        assert_eq!(key, "death.attack.arrow.item");
+        assert_eq!(args.len(), 3);
+        assert_eq!(args[0].plain(), "Steve");
+        assert_eq!(args[1].plain(), "Zombie");
+        assert_eq!(args[2].plain(), "My Sword");
+        // Without a custom name the message keeps its two arguments.
+        let (key, args) = death_message_args("death.attack.arrow", &victim, &cause, None);
+        assert_eq!(key, "death.attack.arrow");
+        assert_eq!(args.len(), 2);
+    }
+}

crates/horizon-client-core/src/sound_source.rs

@@ -0,0 +1,7 @@
+//! Sound sources (`SoundSource`), by name.
+
+/// SoundSource names in vanilla order.
+pub const SOUND_SOURCES: [&str; 11] = [
+    "master", "music", "record", "weather", "block", "hostile", "neutral", "player", "ambient",
+    "voice", "ui",
+];

crates/horizon-client-core/src/text.rs

@@ -42,17 +42,50 @@ pub fn named_color(name: &str) -> Option<u32> {
 /// Click actions carried by locally constructed text components.
 #[derive(Clone, Debug, PartialEq, Eq)]
 pub enum ClickEvent {
+    /// `ClickEvent.OpenUrl`: an http or https link.
+    OpenUrl(String),
+    /// `ClickEvent.ChangePage`: a book's page, counted from 1.
+    ChangePage(i32),
     SuggestCommand(String),
+    /// `ClickEvent.RunCommand`: the command, with or without its `/`.
+    RunCommand(String),
     CopyToClipboard(String),
+    /// `ClickEvent.ShowDialog`: a `minecraft:dialog` registry id, or the
+    /// dialog itself as the component carried it.
+    ShowDialog(horizon_world::nbt::Tag),
     /// A local file to open with the system handler.
     /// Only allow this in locally constructed messages, never server/LAN text.
     OpenFile(String),
 }
 
+/// A non-character `minecraft:object` embedded in a text component.
+#[derive(Clone, Debug, PartialEq, Eq)]
+pub enum InlineObject {
+    Player {
+        profile: Value,
+        hat: bool,
+        fallback: String,
+    },
+    Atlas {
+        atlas: String,
+        sprite: String,
+        fallback: String,
+    },
+}
+impl InlineObject {
+    pub fn fallback(&self) -> &str {
+        match self {
+            Self::Player { fallback, .. } | Self::Atlas { fallback, .. } => fallback,
+        }
+    }
+}
+
 /// Text style; `None` fields inherit from the enclosing style.
 #[derive(Clone, Debug, Default, PartialEq, Eq)]
 pub struct Style {
     pub color: Option<u32>,
+    /// Text component `shadow_color` as packed ARGB. Zero suppresses shadows.
+    pub shadow_color: Option<u32>,
     pub bold: Option<bool>,
     pub italic: Option<bool>,
     pub underlined: Option<bool>,
@@ -61,13 +94,19 @@ pub struct Style {
     pub click: Option<ClickEvent>,
     /// Hover text.
     pub hover: Option<Box<Text>>,
+    /// `HoverEvent.ShowItem`: the event's `{id, count?, components?}` object.
+    pub hover_item: Option<Box<Value>>,
+    /// `Style.insertion`: the text a Shift-click puts in the chat box.
+    pub insertion: Option<String>,
     /// The font (`FontDescription.Resource`), a full id like
     /// `minecraft:alt`; the default font when unset.
     pub font: Option<String>,
+    /// Content metadata for a single U+FFFC object span; never inherited.
+    pub inline_object: Option<InlineObject>,
 }
 /// A style's `font` field: an identifier (`alt` is `minecraft:alt`).
 pub fn font_id(v: &Value) -> Option<String> {
-    crate::command::args::parse_identifier(v.as_str()?)
+    crate::identifier::parse_identifier(v.as_str()?)
 }
 impl Style {
     pub fn color(c: u32) -> Self {
@@ -79,6 +118,7 @@ impl Style {
     /// Fill unset fields from `base` (Style.applyTo).
     pub fn inherit(&mut self, base: &Style) {
         self.color = self.color.or(base.color);
+        self.shadow_color = self.shadow_color.or(base.shadow_color);
         self.bold = self.bold.or(base.bold);
         self.italic = self.italic.or(base.italic);
         self.underlined = self.underlined.or(base.underlined);
@@ -90,6 +130,12 @@ impl Style {
         if self.hover.is_none() {
             self.hover.clone_from(&base.hover);
         }
+        if self.hover_item.is_none() {
+            self.hover_item.clone_from(&base.hover_item);
+        }
+        if self.insertion.is_none() {
+            self.insertion.clone_from(&base.insertion);
+        }
         if self.font.is_none() {
             self.font.clone_from(&base.font);
         }
@@ -318,7 +364,13 @@ impl Text {
     }
     /// Component.getString: the plain characters.
     pub fn plain(&self) -> String {
-        self.spans.iter().map(|s| s.text.as_str()).collect()
+        self.spans
+            .iter()
+            .map(|s| match &s.style.inline_object {
+                Some(object) if s.text == "\u{fffc}" => object.fallback(),
+                _ => s.text.as_str(),
+            })
+            .collect()
     }
     pub fn is_empty(&self) -> bool {
         self.spans.iter().all(|s| s.text.is_empty())
@@ -384,31 +436,7 @@ impl Text {
                     continue;
                 }
                 let Some(code) = chars.next() else { break };
-                let code = code.to_ascii_lowercase();
-                let next = if let Some(c) = COLORS.iter().find(|c| c.0 == code) {
-                    // Style.applyLegacyFormat: a colour clears the decorations.
-                    Style {
-                        color: Some(c.2),
-                        bold: Some(false),
-                        italic: Some(false),
-                        underlined: Some(false),
-                        strikethrough: Some(false),
-                        obfuscated: Some(false),
-                        ..style.clone()
-                    }
-                } else {
-                    let mut s = style.clone();
-                    match code {
-                        'k' => s.obfuscated = Some(true),
-                        'l' => s.bold = Some(true),
-                        'm' => s.strikethrough = Some(true),
-                        'n' => s.underlined = Some(true),
-                        'o' => s.italic = Some(true),
-                        'r' => s = span.style.clone(),
-                        _ => {}
-                    }
-                    s
-                };
+                let next = legacy_format(&style, code, &span.style);
                 if next != style {
                     if !current.is_empty() {
                         out.spans.push(Span {
@@ -495,8 +523,9 @@ impl Text {
 }
 
 /// The style fields of a component's JSON.
-const STYLE_KEYS: [&str; 9] = [
+const STYLE_KEYS: [&str; 11] = [
     "color",
+    "shadow_color",
     "bold",
     "italic",
     "underlined",
@@ -504,6 +533,7 @@ const STYLE_KEYS: [&str; 9] = [
     "obfuscated",
     "click_event",
     "hover_event",
+    "insertion",
     "font",
 ];
 /// Style.Serializer: the fields a style sets.
@@ -516,6 +546,9 @@ fn style_json(style: &Style) -> Vec<(String, Value)> {
             .map_or_else(|| format!("#{c:06X}"), |n| n.1.to_owned());
         out.push(("color".to_owned(), name.into()));
     }
+    if let Some(shadow) = style.shadow_color {
+        out.push(("shadow_color".to_owned(), Value::from(shadow as i32)));
+    }
     for (key, flag) in [
         ("bold", style.bold),
         ("italic", style.italic),
@@ -529,12 +562,22 @@ fn style_json(style: &Style) -> Vec<(String, Value)> {
     }
     if let Some(click) = &style.click {
         let event = match click {
+            ClickEvent::OpenUrl(url) => json!({ "action": "open_url", "url": url }),
+            ClickEvent::ChangePage(page) => json!({ "action": "change_page", "page": page }),
             ClickEvent::SuggestCommand(command) => {
                 json!({ "action": "suggest_command", "command": command })
             }
             ClickEvent::CopyToClipboard(value) => {
                 json!({ "action": "copy_to_clipboard", "value": value })
             }
+            ClickEvent::RunCommand(command) => {
+                json!({ "action": "run_command", "command": command })
+            }
+            // ClickEvent.ShowDialog.CODEC: the dialog the server sent it with.
+            ClickEvent::ShowDialog(dialog) => json!({
+                "action": "show_dialog",
+                "dialog": crate::scoreboard::tag_to_json(dialog),
+            }),
             ClickEvent::OpenFile(path) => json!({ "action": "open_file", "path": path }),
         };
         out.push(("click_event".to_owned(), event));
@@ -544,6 +587,13 @@ fn style_json(style: &Style) -> Vec<(String, Value)> {
             "hover_event".to_owned(),
             json!({ "action": "show_text", "value": hover.component() }),
         ));
+    } else if let Some(Value::Object(item)) = style.hover_item.as_deref() {
+        let mut event = item.clone();
+        event.insert("action".into(), "show_item".into());
+        out.push(("hover_event".to_owned(), Value::Object(event)));
+    }
+    if let Some(insertion) = &style.insertion {
+        out.push(("insertion".to_owned(), insertion.clone().into()));
     }
     if let Some(font) = &style.font {
         out.push(("font".to_owned(), font.clone().into()));
@@ -551,6 +601,35 @@ fn style_json(style: &Style) -> Vec<(String, Value)> {
     out
 }
 
+/// `Style.applyLegacyFormat` for the code after a `§`, `§r` going back to
+/// `reset` (`StringDecomposer.iterateFormatted`); an unknown code changes nothing.
+pub fn legacy_format(style: &Style, code: char, reset: &Style) -> Style {
+    let code = code.to_ascii_lowercase();
+    if let Some(c) = COLORS.iter().find(|c| c.0 == code) {
+        // A colour clears the decorations.
+        return Style {
+            color: Some(c.2),
+            bold: Some(false),
+            italic: Some(false),
+            underlined: Some(false),
+            strikethrough: Some(false),
+            obfuscated: Some(false),
+            ..style.clone()
+        };
+    }
+    let mut s = style.clone();
+    match code {
+        'k' => s.obfuscated = Some(true),
+        'l' => s.bold = Some(true),
+        'm' => s.strikethrough = Some(true),
+        'n' => s.underlined = Some(true),
+        'o' => s.italic = Some(true),
+        'r' => s = reset.clone(),
+        _ => {}
+    }
+    s
+}
+
 /// TranslatableContents.decomposeTemplate: `%s` takes the next argument,
 /// `%n$s` a numbered one and `%%` is a percent sign. Malformed templates are
 /// shown verbatim.

crates/horizon-client-core/src/uuid.rs

@@ -0,0 +1,24 @@
+//! UUIDs as vanilla's four-int form, to and from their text form.
+
+pub fn uuid_text(u: [i32; 4]) -> String {
+    let hex: String = u.iter().map(|v| format!("{:08x}", *v as u32)).collect();
+    format!(
+        "{}-{}-{}-{}-{}",
+        &hex[0..8],
+        &hex[8..12],
+        &hex[12..16],
+        &hex[16..20],
+        &hex[20..32]
+    )
+}
+pub fn uuid_from_text(s: &str) -> Option<[i32; 4]> {
+    let hex: String = s.chars().filter(|c| *c != '-').collect();
+    if hex.len() != 32 {
+        return None;
+    }
+    let mut out = [0i32; 4];
+    for (i, v) in out.iter_mut().enumerate() {
+        *v = u32::from_str_radix(&hex[i * 8..i * 8 + 8], 16).ok()? as i32;
+    }
+    Some(out)
+}

crates/horizon-client-core/src/who.rs

@@ -0,0 +1,8 @@
+//! Who an action came from or is aimed at: the player or a mob by id.
+
+/// Who caused damage or is being targeted.
+#[derive(Clone, Copy, Debug, PartialEq, Eq, Hash)]
+pub enum Who {
+    Player,
+    Mob(u32),
+}

crates/horizon-client-input/Cargo.toml

@@ -0,0 +1,23 @@
+[package]
+name = "horizon-client-input"
+version = "0.1.0"
+edition.workspace = true
+license.workspace = true
+rust-version = "1.90"
+description = "The client's input layer: key bindings and their names, mouse, controllers, clipboard and window options"
+
+[dependencies]
+horizon-client-core = { path = "../horizon-client-core" }
+winit = "0.30.13"
+# The window icon.
+horizon-theme = { path = "../horizon-theme" }
+png = "0.18"
+arboard = { version = "3.6.1", default-features = false, features = ["wayland-data-control"] }
+# The DualSense's trigger effects (the `controllers` feature).
+horizon-dualsense = { path = "../horizon-dualsense", optional = true }
+
+[features]
+controllers = ["dep:horizon-dualsense"]
+
+[lints]
+workspace = true

crates/horizon-client-input/src/clipboard.rs

@@ -60,6 +60,19 @@ pub fn edit_shortcut(
     })
 }
 
+/// Windows reports AltGr as Ctrl plus Alt: the system presses a left Control
+/// in front of the right Alt.
+pub const ALTGR_IS_CTRL_ALT: bool = cfg!(windows);
+
+/// Whether a key's text reaches the screen (`KeyboardHandler.textInput`, then
+/// `charTyped` per code point). The edit modifier's shortcuts type nothing,
+/// but `textInput` takes no modifiers: with AltGr held (Ctrl plus Alt where
+/// `altgr_is_ctrl_alt`) the layout's third-level characters are text, as `/`
+/// on ABNT2, `@`, `{` and `[` on German or the Polish letters.
+pub fn types_text(edit_modifier: bool, alt: bool, altgr_is_ctrl_alt: bool) -> bool {
+    !edit_modifier || (altgr_is_ctrl_alt && alt)
+}
+
 /// `StringUtil.isAllowedChatCharacter`.
 pub fn is_allowed_chat_character(c: char) -> bool {
     c != '§' && c >= ' ' && c != '\u{7f}'
@@ -303,6 +316,22 @@ pub fn append_limited(value: &mut String, text: &str, max_chars: usize) -> bool
 mod tests {
     use super::*;
 
+    #[test]
+    fn altgr_types_text_where_it_is_ctrl_alt() {
+        // Plain keys and Shift type.
+        assert!(types_text(false, false, true));
+        assert!(types_text(false, false, false));
+        // Ctrl (Cmd) shortcuts do not.
+        assert!(!types_text(true, false, true));
+        assert!(!types_text(true, false, false));
+        // AltGr on Windows is Ctrl+Alt: ABNT2 `/`, German `@` type.
+        assert!(types_text(true, true, true));
+        // Where AltGr is its own modifier, Ctrl+Alt is a shortcut.
+        assert!(!types_text(true, true, false));
+        // Alt alone (macOS Option, Linux AltGr) types.
+        assert!(types_text(false, true, false));
+    }
+
     #[test]
     fn shortcuts_need_the_edit_modifier_alone() {
         let c = Some('c');

crates/horizon-client-input/src/interaction_input.rs

@@ -13,6 +13,12 @@ pub enum Button {
 }
 
 pub trait InteractionWorld {
+    /// Minecraft.pick before handleKeybinds: the tick's `hitResult`, which
+    /// every click of the tick reads, even after one of them changed the
+    /// block it names (a creative break, then a use that replaces it).
+    fn pick_hit_result(&mut self);
+    /// The tick's clicks are done: later picks follow the crosshair again.
+    fn release_hit_result(&mut self);
     fn using_item(&self) -> bool;
     fn release_using(&mut self);
     fn start_attack(&mut self) -> bool;
@@ -48,6 +54,7 @@ impl InteractionInput {
 
     pub fn tick(&mut self, world: &mut impl InteractionWorld, attack_down: bool, use_down: bool) {
         let [attack, use_item, pick] = std::mem::take(&mut self.clicks);
+        world.pick_hit_result();
         let mut instant = false;
         if world.using_item() {
             if !use_down {
@@ -70,6 +77,7 @@ impl InteractionInput {
             world.start_use();
         }
         world.continue_attack(!instant && attack_down);
+        world.release_hit_result();
     }
 }
 
@@ -86,6 +94,8 @@ mod tests {
         events: Vec<&'static str>,
     }
     impl InteractionWorld for World {
+        fn pick_hit_result(&mut self) {}
+        fn release_hit_result(&mut self) {}
         fn using_item(&self) -> bool {
             self.using
         }
@@ -183,4 +193,67 @@ mod tests {
         input.tick(&mut world, false, false);
         assert_eq!(world.events, ["release", "continue"]);
     }
+
+    /// A floating block in front of the crosshair, nothing behind it, and a
+    /// block item in the hand of a creative player.
+    #[derive(Default)]
+    struct Column {
+        block: bool,
+        hit: Option<Option<()>>,
+        placed: bool,
+    }
+    impl Column {
+        /// Minecraft.hitResult: the tick's pick, or a fresh one outside it.
+        fn target(&self) -> Option<()> {
+            self.hit.unwrap_or(self.block.then_some(()))
+        }
+    }
+    impl InteractionWorld for Column {
+        fn pick_hit_result(&mut self) {
+            self.hit = Some(self.target());
+        }
+        fn release_hit_result(&mut self) {
+            self.hit = None;
+        }
+        fn using_item(&self) -> bool {
+            false
+        }
+        fn release_using(&mut self) {}
+        fn start_attack(&mut self) -> bool {
+            // MultiPlayerGameMode.startDestroyBlock in creative: the
+            // predicted break leaves air.
+            if self.target().is_some() {
+                self.block = false;
+            }
+            !self.block
+        }
+        fn start_use(&mut self) {
+            // BlockItem.place: the clicked block, now air, can be replaced.
+            if self.target().is_some() && !self.block {
+                self.block = true;
+                self.placed = true;
+            }
+        }
+        fn pick(&mut self) {}
+        fn use_delay(&self) -> u32 {
+            0
+        }
+        fn continue_attack(&mut self, _: bool) {}
+    }
+
+    #[test]
+    fn attack_and_use_in_one_tick_share_the_hit_result() {
+        // #3006: both buttons at once replace the block the crosshair is on.
+        let mut input = InteractionInput::default();
+        let mut world = Column {
+            block: true,
+            ..Default::default()
+        };
+        input.press(Button::Attack);
+        input.press(Button::Use);
+        input.tick(&mut world, false, false);
+        assert!(world.placed, "the use acts on the block the attack broke");
+        assert!(world.block);
+        assert!(world.hit.is_none(), "the next pick follows the crosshair");
+    }
 }

crates/horizon-client-input/src/keybinds.rs

@@ -2,7 +2,6 @@
 //! defaults, `key_<name>:key.keyboard.x` persistence, display names, and the
 //! translation of rebound physical keys back to the default keys the game
 //! logic listens for.
-use crate::text::Text;
 use std::collections::BTreeMap;
 use winit::{event::MouseButton, keyboard::KeyCode};
 
@@ -146,6 +145,22 @@ const KEYS: &[(&str, KeyCode)] = &[
     ("key.keyboard.period", KeyCode::Period),
     ("key.keyboard.slash", KeyCode::Slash),
     ("key.keyboard.caps.lock", KeyCode::CapsLock),
+    ("key.keyboard.world.1", KeyCode::IntlBackslash),
+    ("key.keyboard.international1", KeyCode::IntlRo),
+    ("key.keyboard.international3", KeyCode::IntlYen),
+    ("key.keyboard.lang1", KeyCode::Lang1),
+    ("key.keyboard.lang2", KeyCode::Lang2),
+    ("key.keyboard.lang3", KeyCode::Lang3),
+    ("key.keyboard.lang4", KeyCode::Lang4),
+    ("key.keyboard.lang5", KeyCode::Lang5),
+    ("key.keyboard.help", KeyCode::Help),
+    ("key.keyboard.select", KeyCode::Select),
+    ("key.keyboard.again", KeyCode::Again),
+    ("key.keyboard.undo", KeyCode::Undo),
+    ("key.keyboard.cut", KeyCode::Cut),
+    ("key.keyboard.copy", KeyCode::Copy),
+    ("key.keyboard.paste", KeyCode::Paste),
+    ("key.keyboard.find", KeyCode::Find),
     ("key.keyboard.f1", KeyCode::F1),
     ("key.keyboard.f2", KeyCode::F2),
     ("key.keyboard.f3", KeyCode::F3),
@@ -158,6 +173,18 @@ const KEYS: &[(&str, KeyCode)] = &[
     ("key.keyboard.f10", KeyCode::F10),
     ("key.keyboard.f11", KeyCode::F11),
     ("key.keyboard.f12", KeyCode::F12),
+    ("key.keyboard.f13", KeyCode::F13),
+    ("key.keyboard.f14", KeyCode::F14),
+    ("key.keyboard.f15", KeyCode::F15),
+    ("key.keyboard.f16", KeyCode::F16),
+    ("key.keyboard.f17", KeyCode::F17),
+    ("key.keyboard.f18", KeyCode::F18),
+    ("key.keyboard.f19", KeyCode::F19),
+    ("key.keyboard.f20", KeyCode::F20),
+    ("key.keyboard.f21", KeyCode::F21),
+    ("key.keyboard.f22", KeyCode::F22),
+    ("key.keyboard.f23", KeyCode::F23),
+    ("key.keyboard.f24", KeyCode::F24),
     ("key.keyboard.print.screen", KeyCode::PrintScreen),
     ("key.keyboard.scroll.lock", KeyCode::ScrollLock),
     ("key.keyboard.pause", KeyCode::Pause),
@@ -189,6 +216,36 @@ const KEYS: &[(&str, KeyCode)] = &[
     ("key.keyboard.keypad.0", KeyCode::Numpad0),
     ("key.keyboard.keypad.period", KeyCode::NumpadDecimal),
     ("key.keyboard.keypad.equal", KeyCode::NumpadEqual),
+    ("key.keyboard.keypad.comma", KeyCode::NumpadComma),
+    ("key.keyboard.keypad.backspace", KeyCode::NumpadBackspace),
+    (
+        "key.keyboard.keypad.left.parenthesis",
+        KeyCode::NumpadParenLeft,
+    ),
+    (
+        "key.keyboard.keypad.right.parenthesis",
+        KeyCode::NumpadParenRight,
+    ),
+    ("key.keyboard.keypad.hash", KeyCode::NumpadHash),
+    (
+        "key.keyboard.keypad.memory.store",
+        KeyCode::NumpadMemoryStore,
+    ),
+    (
+        "key.keyboard.keypad.memory.recall",
+        KeyCode::NumpadMemoryRecall,
+    ),
+    (
+        "key.keyboard.keypad.memory.clear",
+        KeyCode::NumpadMemoryClear,
+    ),
+    ("key.keyboard.keypad.memory.add", KeyCode::NumpadMemoryAdd),
+    (
+        "key.keyboard.keypad.memory.subtract",
+        KeyCode::NumpadMemorySubtract,
+    ),
+    ("key.keyboard.keypad.clear", KeyCode::NumpadClear),
+    ("key.keyboard.keypad.clear.entry", KeyCode::NumpadClearEntry),
     ("key.keyboard.menu", KeyCode::ContextMenu),
     ("key.keyboard.left.control", KeyCode::ControlLeft),
     ("key.keyboard.left.shift", KeyCode::ShiftLeft),
@@ -225,40 +282,7 @@ pub fn mouse_button(name: &str) -> Option<MouseButton> {
         _ => return None,
     })
 }
-/// InputConstants.Key.getDisplayName: one-character keys as the upper-case
-/// character, others by translation.
-pub fn display_name(key: &str) -> Text {
-    if let Some(rest) = key.strip_prefix("key.keyboard.")
-        && rest.chars().count() == 1
-    {
-        let c = rest.to_uppercase();
-        return Text::literal(c);
-    }
-    let symbol = match key {
-        "key.keyboard.minus" => Some("-"),
-        "key.keyboard.equal" => Some("="),
-        "key.keyboard.left.bracket" => Some("["),
-        "key.keyboard.right.bracket" => Some("]"),
-        "key.keyboard.backslash" => Some("\\"),
-        "key.keyboard.semicolon" => Some(";"),
-        "key.keyboard.apostrophe" => Some("'"),
-        "key.keyboard.grave.accent" => Some("`"),
-        "key.keyboard.comma" => Some(","),
-        "key.keyboard.period" => Some("."),
-        "key.keyboard.slash" => Some("/"),
-        _ => None,
-    };
-    if let Some(s) = symbol {
-        return Text::literal(s);
-    }
-    if let Some(n) = key.strip_prefix("key.mouse.")
-        && n.parse::<u32>().is_ok()
-        && !crate::lang::has(key)
-    {
-        return Text::translate("key.mouse", &[Text::literal(n)]);
-    }
-    Text::translate(key, &[])
-}
+pub use horizon_client_core::key_display::display_name;
 
 /// Current bindings by mapping name.
 #[derive(Clone, Debug, PartialEq, Eq)]
@@ -275,6 +299,19 @@ impl Default for KeyBinds {
         }
     }
 }
+/// Each default key once, in order: two mappings that share a default key
+/// (Pick Block and the spectator hotbar both on the middle button) are one
+/// press of it, not two.
+fn distinct<T: PartialEq>(keys: Vec<T>) -> Vec<T> {
+    let mut out = Vec::with_capacity(keys.len());
+    for k in keys {
+        if !out.contains(&k) {
+            out.push(k);
+        }
+    }
+    out
+}
+
 impl KeyBinds {
     pub fn get(&self, name: &str) -> &str {
         self.keys
@@ -320,49 +357,93 @@ impl KeyBinds {
     }
     /// The mapping a physical input triggers (first in list order).
     pub fn mapping_for(&self, key: &str) -> Option<&'static str> {
-        MAPPINGS.iter().map(|m| m.0).find(|n| self.get(n) == key)
+        self.mappings_for(key).next()
+    }
+    /// Every mapping a physical input triggers, in list order: like
+    /// `KeyMapping.set`/`click`, one key drives all the mappings bound to it.
+    pub fn mappings_for<'a>(&'a self, key: &'a str) -> impl Iterator<Item = &'static str> + 'a {
+        MAPPINGS
+            .iter()
+            .map(|m| m.0)
+            .filter(move |n| self.get(n) == key)
+    }
+    /// The mappings bound to `key` that [`KeyBinds::translate_all`] follows:
+    /// all but the debug keys. Those act only with F3 held
+    /// (`KeyboardHandler.handleDebugKeys`, `debug_keys.rs` reads the physical
+    /// key and the binding itself); their defaults (A, S, D, T, L, 1 to 4...)
+    /// would otherwise turn the key back into its old gameplay meaning.
+    fn translated_mappings<'a>(&'a self, key: &'a str) -> impl Iterator<Item = &'static str> + 'a {
+        MAPPINGS
+            .iter()
+            .filter(|m| m.2 != "debug")
+            .map(|m| m.0)
+            .filter(move |n| self.get(n) == key)
+    }
+    /// Whether a mapping (other than a debug key) whose default is `key` was
+    /// bound elsewhere.
+    fn default_moved(&self, key: &str) -> bool {
+        MAPPINGS
+            .iter()
+            .any(|(n, d, c)| *d == key && *c != "debug" && !self.is_default(n))
     }
     /// Translate a physical key into the default key of the mapping it is
     /// bound to, so game code written against vanilla defaults follows the
     /// player's bindings. `None` means the key now does nothing; mouse
-    /// mappings bound to keys come back as `Err(button)`.
+    /// mappings bound to keys come back as `Err(button)`. The first of
+    /// [`KeyBinds::translate_all`].
     pub fn translate(&self, key: KeyCode) -> Option<Result<KeyCode, MouseButton>> {
+        self.translate_all(key).into_iter().next()
+    }
+    /// The default keys of every mapping `key` is bound to (empty when it
+    /// now does nothing), so a key bound to two mappings (forward and
+    /// sprint) drives both, as `KeyMapping.set` does.
+    pub fn translate_all(&self, key: KeyCode) -> Vec<Result<KeyCode, MouseButton>> {
         let Some(name) = key_name(key) else {
-            return Some(Ok(key));
+            return vec![Ok(key)];
         };
-        if let Some(mapping) = self.mapping_for(name) {
-            let default = Self::default_of(mapping);
-            if let Some(code) = key_code(default) {
-                return Some(Ok(code));
-            }
-            return mouse_button(default).map(Err);
+        let bound: Vec<_> = self
+            .translated_mappings(name)
+            .filter_map(|mapping| {
+                let default = Self::default_of(mapping);
+                match key_code(default) {
+                    Some(code) => Some(Ok(code)),
+                    None => mouse_button(default).map(Err),
+                }
+            })
+            .collect();
+        if !bound.is_empty() {
+            return distinct(bound);
         }
         // An unbound key whose default meaning was moved elsewhere is inert.
-        if MAPPINGS
-            .iter()
-            .any(|(n, d, _)| *d == name && !self.is_default(n))
-        {
-            return None;
+        if self.default_moved(name) {
+            return Vec::new();
         }
-        Some(Ok(key))
+        vec![Ok(key)]
     }
     /// Translate a mouse button the same way (keys bound to mouse buttons).
     pub fn translate_mouse(&self, button: MouseButton) -> Option<Result<KeyCode, MouseButton>> {
+        self.translate_mouse_all(button).into_iter().next()
+    }
+    /// [`KeyBinds::translate_all`] for a mouse button.
+    pub fn translate_mouse_all(&self, button: MouseButton) -> Vec<Result<KeyCode, MouseButton>> {
         let name = mouse_name(button);
-        if let Some(mapping) = self.mapping_for(&name) {
-            let default = Self::default_of(mapping);
-            if let Some(b) = mouse_button(default) {
-                return Some(Err(b));
-            }
-            return key_code(default).map(Ok);
+        let bound: Vec<_> = self
+            .translated_mappings(&name)
+            .filter_map(|mapping| {
+                let default = Self::default_of(mapping);
+                match mouse_button(default) {
+                    Some(b) => Some(Err(b)),
+                    None => key_code(default).map(Ok),
+                }
+            })
+            .collect();
+        if !bound.is_empty() {
+            return distinct(bound);
         }
-        if MAPPINGS
-            .iter()
-            .any(|(n, d, _)| *d == name && !self.is_default(n))
-        {
-            return None;
+        if self.default_moved(&name) {
+            return Vec::new();
         }
-        Some(Err(button))
+        vec![Err(button)]
     }
     /// `AbstractContainerScreen.checkHotbarMouseClicked`: off hand, then hotbar.
     pub fn container_mouse_key(&self, button: MouseButton, creative: bool) -> Option<KeyCode> {
@@ -439,6 +520,29 @@ mod tests {
         assert_eq!(k.conflicts("key.forward"), ["key.jump"]);
     }
     #[test]
+    fn a_moved_key_keeps_no_default_action() {
+        // #3158: the debug keys (F3+A, F3+1...) share these keys' defaults,
+        // and must not hand them back their gameplay meaning.
+        let mut k = KeyBinds::default();
+        k.set("key.hotbar.1", "key.keyboard.q");
+        assert_eq!(k.translate_all(KeyCode::Digit1), []);
+        assert_eq!(
+            k.translate_all(KeyCode::KeyQ),
+            [Ok(KeyCode::KeyQ), Ok(KeyCode::Digit1)]
+        );
+        k.set("key.inventory", "key.keyboard.a");
+        k.set("key.left", "key.keyboard.e");
+        assert_eq!(k.translate_all(KeyCode::KeyA), [Ok(KeyCode::KeyE)]);
+        assert_eq!(k.translate_all(KeyCode::KeyE), [Ok(KeyCode::KeyA)]);
+        k.set("key.back", "key.keyboard.down");
+        assert_eq!(k.translate_all(KeyCode::KeyS), []);
+        // Keys left alone still act, and a moved debug key changes nothing.
+        k.set("key.debug.fpsCharts", "key.keyboard.9");
+        assert_eq!(k.translate_all(KeyCode::Digit2), [Ok(KeyCode::Digit2)]);
+        assert_eq!(k.translate_all(KeyCode::Digit9), [Ok(KeyCode::Digit9)]);
+        assert_eq!(k.translate_all(KeyCode::F3), [Ok(KeyCode::F3)]);
+    }
+    #[test]
     fn display_names() {
         assert_eq!(display_name("key.keyboard.w").plain(), "W");
         assert_eq!(display_name("key.keyboard.slash").plain(), "/");

crates/horizon-client-input/src/lib.rs

@@ -0,0 +1,14 @@
+//! The client's input layer, below gameplay and screens: key bindings and their
+//! names, toggle keys, mouse settings, controllers, the clipboard and window
+//! options. horizon-client re-exports each module under its old path
+//! (`horizon_client::keybinds`, ...).
+#![forbid(unsafe_code)]
+pub mod clipboard;
+pub mod gamepad;
+pub mod input;
+pub mod interaction_input;
+pub mod key_names;
+pub mod keybinds;
+pub mod keymapping;
+pub mod mouse;
+pub mod window;

crates/horizon-client-input/src/mouse.rs

@@ -324,6 +324,24 @@ pub fn ease_in_out(t: f64) -> f64 {
     0.5 - 0.5 * (std::f64::consts::PI * t).cos()
 }
 
+/// `MouseHandler.grabMouse` / `releaseMouse`: the mouse position is the
+/// window's centre whenever the pointer's grab state changes, so a screen
+/// opened from gameplay starts with the cursor in the middle. A release of
+/// an already free pointer (or a grab of an already grabbed one) leaves the
+/// position where it is, as vanilla does.
+pub fn mouse_position_after_grab_change(
+    grab: bool,
+    was_grabbed: bool,
+    size: [u32; 2],
+    scale: f32,
+) -> Option<(f32, f32)> {
+    if grab == was_grabbed {
+        None
+    } else {
+        Some((size[0] as f32 / 2.0 / scale, size[1] as f32 / 2.0 / scale))
+    }
+}
+
 #[cfg(test)]
 mod tests {
     use super::*;
@@ -485,4 +503,27 @@ mod tests {
         assert_eq!(look.on_scroll(0.0, 0.4, false, 1.0), None);
         assert_eq!(look.on_scroll(0.0, 0.7, false, 1.0), Some((1, (0, 1))));
     }
+    #[test]
+    fn the_mouse_position_is_the_centre_when_the_grab_changes() {
+        // A grab of a free pointer and a release of a grabbed one both put
+        // the position at the window's centre (`MouseHandler.grabMouse`,
+        // `MouseHandler.releaseMouse`).
+        assert_eq!(
+            mouse_position_after_grab_change(true, false, [1920, 1080], 1.0),
+            Some((960.0, 540.0))
+        );
+        assert_eq!(
+            mouse_position_after_grab_change(false, true, [1920, 1080], 2.0),
+            Some((480.0, 270.0))
+        );
+        // Without a change of the grab state the position stays where it is.
+        assert_eq!(
+            mouse_position_after_grab_change(false, false, [1920, 1080], 1.0),
+            None
+        );
+        assert_eq!(
+            mouse_position_after_grab_change(true, true, [1920, 1080], 1.0),
+            None
+        );
+    }
 }

crates/horizon-client-render/Cargo.toml

@@ -0,0 +1,67 @@
+[package]
+name = "horizon-client-render"
+version = "0.1.0"
+edition.workspace = true
+license.workspace = true
+rust-version = "1.90"
+description = "The client's world data, rendering and screens: chunks, meshing, light, streaming, the renderer, the HUD, menus and settings; no gameplay"
+
+[dependencies]
+horizon-assets = { path = "../horizon-assets" }
+horizon-bench = { path = "../horizon-bench" }
+horizon-client-core = { path = "../horizon-client-core" }
+horizon-client-input = { path = "../horizon-client-input" }
+horizon-command = { path = "../horizon-command" }
+horizon-core = { path = "../horizon-core" }
+horizon-hdr = { path = "../horizon-hdr" }
+horizon-items = { path = "../horizon-items" }
+horizon-protocol = { path = "../horizon-protocol" }
+horizon-shader-api = { path = "../horizon-shader-api" }
+horizon-shaders = { path = "../horizon-shaders" }
+horizon-telemetry = { path = "../horizon-telemetry", default-features = false, features = ["live"] }
+horizon-theme = { path = "../horizon-theme" }
+horizon-threads = { path = "../horizon-threads" }
+horizon-world = { path = "../horizon-world" }
+ab_glyph = "0.2.32"
+bytemuck = { version = "1.24", features = ["derive"] }
+# Sound (ALSA on Linux); the `audio` feature.
+cpal = { version = "0.16", optional = true }
+chrono = { version = "0.4.42", default-features = false, features = ["clock", "std"] }
+flate2 = { version = "1.1.10", default-features = false, features = ["zlib-rs", "runtime_detection"] }
+glam = "0.30"
+log = "0.4"
+miniz_oxide = "0.8"
+naga = { version = "30.0.1", features = ["wgsl-in", "hlsl-out"] }
+png = "0.18"
+pollster = "0.4"
+serde = { version = "1", features = ["derive"] }
+serde_json = { version = "1.0.151", features = ["raw_value"] }
+sha2 = "0.10.9"
+symphonia = { version = "0.5", default-features = false, features = ["ogg", "vorbis"] }
+unicode-bidi = "0.3.18"
+ureq = { version = "2", default-features = false, features = ["tls"] }
+wgpu = { version = "30.0.1", default-features = false, features = ["std", "parking_lot", "vulkan", "metal", "wgsl", "naga-ir"] }
+winit = "0.30.13"
+zip = { version = "2", default-features = false, features = ["deflate"] }
+
+[target.'cfg(unix)'.dependencies]
+rustix = { version = "1", default-features = false, features = ["std", "time"] }
+
+[target.'cfg(windows)'.dependencies]
+wgpu = { version = "30.0.1", default-features = false, features = ["dx12"] }
+
+[target.'cfg(not(target_os = "macos"))'.dependencies]
+wgpu = { version = "30.0.1", default-features = false, features = ["gles"] }
+
+[features]
+# Sound output: horizon-client's `audio` feature.
+audio = ["dep:cpal"]
+# Helpers horizon-client's tests build their fixtures with.
+test-support = []
+
+[lints]
+workspace = true
+
+[dev-dependencies]
+horizon-items = { path = "../horizon-items", features = ["test-support"] }
+naga = { version = "30.0.1", features = ["wgsl-in", "hlsl-out", "msl-out", "spv-out"] }

crates/horizon-client-render/examples/compositor.rs

@@ -0,0 +1,151 @@
+//! Two offscreen frames presented in one window, without game resources or player data.
+//! `cargo run --profile fast -p horizon-client-render --example compositor -- --smoke`
+use horizon_client_render::gfx::compositor::Compositor;
+use std::sync::Arc;
+use winit::{
+    application::ApplicationHandler,
+    event::WindowEvent,
+    event_loop::{ActiveEventLoop, EventLoop},
+    window::{Window, WindowId},
+};
+
+struct Frames {
+    window: Arc<Window>,
+    compositor: Compositor,
+    textures: [wgpu::Texture; 2],
+}
+
+impl Frames {
+    fn new(event_loop: &ActiveEventLoop) -> horizon_client_render::Result<Self> {
+        let window = Arc::new(
+            event_loop.create_window(
+                Window::default_attributes()
+                    .with_title("Compositor: red and blue views")
+                    .with_inner_size(winit::dpi::PhysicalSize::new(640, 360)),
+            )?,
+        );
+        let instance = wgpu::Instance::new(wgpu::InstanceDescriptor::new_with_display_handle(
+            Box::new(window.clone()),
+        ));
+        let surface = instance.create_surface(window.clone())?;
+        let adapter = pollster::block_on(instance.request_adapter(&wgpu::RequestAdapterOptions {
+            compatible_surface: Some(&surface),
+            ..Default::default()
+        }))?;
+        let (device, queue) = pollster::block_on(adapter.request_device(&Default::default()))?;
+        let textures = [[0, 0, 255, 255], [255, 0, 0, 255]].map(|pixel| {
+            let size = wgpu::Extent3d {
+                width: 320,
+                height: 360,
+                depth_or_array_layers: 1,
+            };
+            let texture = device.create_texture(&wgpu::TextureDescriptor {
+                label: Some("Offscreen view"),
+                size,
+                mip_level_count: 1,
+                sample_count: 1,
+                dimension: wgpu::TextureDimension::D2,
+                format: wgpu::TextureFormat::Bgra8Unorm,
+                usage: wgpu::TextureUsages::COPY_SRC | wgpu::TextureUsages::COPY_DST,
+                view_formats: &[],
+            });
+            queue.write_texture(
+                texture.as_image_copy(),
+                &pixel.repeat(320 * 360),
+                wgpu::TexelCopyBufferLayout {
+                    offset: 0,
+                    bytes_per_row: Some(320 * 4),
+                    rows_per_image: Some(360),
+                },
+                size,
+            );
+            texture
+        });
+        let compositor = Compositor::new(
+            surface,
+            &adapter,
+            &device,
+            &queue,
+            window.inner_size().into(),
+        )?;
+        Ok(Self {
+            window,
+            compositor,
+            textures,
+        })
+    }
+}
+
+#[derive(Default)]
+struct Demo {
+    frames: Option<Frames>,
+    error: Option<String>,
+    presented: usize,
+    smoke: bool,
+}
+
+impl ApplicationHandler for Demo {
+    fn resumed(&mut self, event_loop: &ActiveEventLoop) {
+        if self.frames.is_none() {
+            match Frames::new(event_loop) {
+                Ok(frames) => self.frames = Some(frames),
+                Err(error) => {
+                    self.error = Some(error.to_string());
+                    event_loop.exit();
+                }
+            }
+        }
+    }
+
+    fn window_event(&mut self, event_loop: &ActiveEventLoop, _: WindowId, event: WindowEvent) {
+        let Some(f) = &mut self.frames else { return };
+        match event {
+            WindowEvent::CloseRequested => event_loop.exit(),
+            WindowEvent::Resized(size) => f.compositor.resize(size.width, size.height),
+            // Uncovered pixels are black; resize smaller to exercise clipping.
+            WindowEvent::RedrawRequested
+                if f.compositor
+                    .present(&[(&f.textures[0], [0, 0]), (&f.textures[1], [320, 0])]) =>
+            {
+                self.presented += 1;
+                if self.smoke && self.presented == 10 {
+                    f.compositor.set_vsync(false);
+                    f.compositor.resize(0, 0);
+                    assert!(!f.compositor.present(&[]));
+                    f.compositor.resize(u32::MAX, u32::MAX);
+                    assert!(!f.compositor.present(&[]));
+                    f.compositor.resize(400, 240);
+                    let _ = f
+                        .window
+                        .request_inner_size(winit::dpi::PhysicalSize::new(400, 240));
+                }
+                if self.smoke && self.presented == 20 {
+                    println!("compositor: 20 frames, resize, suspension and clipping passed");
+                    event_loop.exit();
+                }
+            }
+            _ => {}
+        }
+    }
+
+    fn about_to_wait(&mut self, _: &ActiveEventLoop) {
+        if let Some(f) = &self.frames {
+            f.window.request_redraw();
+        }
+    }
+}
+
+fn main() -> horizon_client_render::Result<()> {
+    let mut demo = Demo {
+        smoke: std::env::args().any(|a| a == "--smoke"),
+        ..Default::default()
+    };
+    EventLoop::new()?.run_app(&mut demo)?;
+    if let Some(error) = demo.error {
+        return Err(error.into());
+    }
+    if demo.smoke && demo.presented < 20 {
+        return Err("smoke test closed early".into());
+    }
+    Ok(())
+}

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

@@ -42,11 +42,11 @@ impl HeightmapState for StateFacts {
 }
 #[derive(Clone)]
 pub struct Properties(Arc<Vec<StateFacts>>);
-#[cfg(test)]
+#[cfg(any(test, feature = "test-support"))]
 impl Properties {
     /// Heightmap facts for tests, per state: (air, has a fluid, blocks
     /// motion, blocks motion but is not leaves). State 0 is minecraft:air.
-    pub(crate) fn for_tests(states: &[(bool, bool, bool, bool)]) -> Self {
+    pub fn for_tests(states: &[(bool, bool, bool, bool)]) -> Self {
         Self(Arc::new(
             states
                 .iter()
@@ -192,11 +192,19 @@ impl Assets {
     pub fn reload(&self, root: &Path) -> Result<RenderAssets> {
         RenderAssets::load(root, self)
     }
+    /// [`Assets::reload`] for a server, which draws nothing: the models and
+    /// the sprites' layers, without the textures' pixels.
+    pub fn reload_for_server(&self, root: &Path) -> Result<RenderAssets> {
+        RenderAssets::load_with(root, self, false)
+    }
 }
 impl RenderAssets {
     pub fn load(root: &Path, assets: &Assets) -> Result<Self> {
+        Self::load_with(root, assets, true)
+    }
+    fn load_with(root: &Path, assets: &Assets, pixels: bool) -> Result<Self> {
         let registry = assets.registry;
-        let mut sprites = crate::sprites::Sprites::default();
+        let mut sprites = crate::sprites::Sprites::with_disk_cache(root);
         for name in MATERIALS {
             sprites.insert(root, &format!("minecraft:block/{name}"))?;
         }
@@ -217,7 +225,14 @@ impl RenderAssets {
         for stage in 0..10 {
             sprites.insert(root, &format!("minecraft:block/destroy_stage_{stage}"))?;
         }
-        sprites.finish();
+        sprites.save_disk_cache();
+        if pixels {
+            sprites.finish();
+        } else {
+            sprites.finish_without_pixels();
+        }
+        // `finish` grows the buffer by doubling: keep only the bytes in use.
+        sprites.pixels.shrink_to_fit();
         Ok(Self {
             sprite_size: sprites.size,
             sprite_minimum_size: sprites.minimum_size,
@@ -234,3 +249,81 @@ impl RenderAssets {
         })
     }
 }
+
+#[cfg(test)]
+mod tests {
+    use crate::items::ConsumeEffect;
+
+    #[test]
+    fn always_edible_and_consume_effects_loaded() {
+        let root = std::path::PathBuf::from(env!("CARGO_MANIFEST_DIR"))
+            .join("../../.local/horizon-client/26.3");
+        if !root.join("items.json").exists() {
+            return;
+        }
+        let assets = crate::assets::Assets::load(&root).unwrap();
+        let facts = crate::blocks::BlockFacts::load(&root, assets.registry).unwrap();
+        let items = crate::items::Items::load(&root, assets.registry, &facts).unwrap();
+
+        let apple = items.get("minecraft:golden_apple").expect("golden apple");
+        assert!(apple.can_always_eat);
+        assert!(apple.food.is_some());
+        assert!(!apple.consumable.as_ref().unwrap().effects.is_empty());
+
+        let enchanted = items
+            .get("minecraft:enchanted_golden_apple")
+            .expect("enchanted golden apple");
+        assert!(enchanted.can_always_eat);
+        assert!(enchanted.food.is_some());
+        assert!(!enchanted.consumable.as_ref().unwrap().effects.is_empty());
+
+        let beef = items.get("minecraft:cooked_beef").expect("cooked beef");
+        assert!(!beef.can_always_eat);
+        assert!(beef.food.is_some());
+
+        // Consumables without food, their style and their remainders.
+        use horizon_world::consumable::UseAnimation;
+        let milk = items.get("minecraft:milk_bucket").expect("milk bucket");
+        let drink = milk.consumable.as_ref().unwrap();
+        assert!(milk.food.is_none());
+        assert_eq!(drink.effects, [ConsumeEffect::ClearAllEffects]);
+        assert_eq!((drink.ticks(), drink.animation), (32, UseAnimation::Drink));
+        assert_eq!(drink.sound, "minecraft:entity.generic.drink");
+        assert!(!drink.particles);
+        assert_eq!(milk.use_remainder.as_deref(), Some("minecraft:bucket"));
+        let honey = items.get("minecraft:honey_bottle").expect("honey bottle");
+        let sip = honey.consumable.as_ref().unwrap();
+        assert_eq!(sip.ticks(), 40);
+        assert_eq!(sip.sound, "minecraft:item.honey_bottle.drink");
+        assert_eq!(
+            sip.effects,
+            [ConsumeEffect::RemoveEffects(vec![
+                "minecraft:poison".into()
+            ])]
+        );
+        assert_eq!(
+            honey.use_remainder.as_deref(),
+            Some("minecraft:glass_bottle")
+        );
+        let kelp = items.get("minecraft:dried_kelp").unwrap();
+        let bite = kelp.consumable.as_ref().unwrap();
+        assert_eq!((bite.ticks(), bite.animation), (16, UseAnimation::Eat));
+        assert_eq!(bite.sound, "minecraft:entity.generic.eat");
+        assert!(bite.particles && kelp.use_remainder.is_none());
+        let chorus = items.get("minecraft:chorus_fruit").unwrap();
+        assert_eq!(
+            chorus.consumable.as_ref().unwrap().effects,
+            [ConsumeEffect::TeleportRandomly(
+                horizon_world::teleport_consume::TeleportConsume {
+                    diameter: 16.0,
+                    directional_particles: true,
+                }
+            )]
+        );
+        let chicken = items.get("minecraft:chicken").unwrap();
+        assert!(matches!(
+            chicken.consumable.as_ref().unwrap().effects[..],
+            [ConsumeEffect::ApplyEffects { probability, .. }] if probability == 0.3
+        ));
+    }
+}

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

@@ -3,8 +3,8 @@
 //! `filter`, `unstitch` and `paletted_permutations` sources run in order
 //! against the resource tree; a later source replaces an earlier sprite of
 //! the same id and a filter removes the matching ones.
-use crate::packs::pattern::Pattern;
 use horizon_assets::palette::apply_palette;
+use horizon_client_core::pattern::Pattern;
 use serde_json::Value;
 use std::{
     collections::BTreeMap,
@@ -187,7 +187,14 @@ pub fn list_textures(root: &Path) -> Vec<String> {
             };
             for e in entries.flatten() {
                 let p = e.path();
-                if p.is_dir() {
+                // `file_type` comes with the listing; `Path::is_dir` is a stat per
+                // entry, kept for links (which it follows).
+                let dir = match e.file_type() {
+                    Ok(t) if t.is_symlink() => p.is_dir(),
+                    Ok(t) => t.is_dir(),
+                    Err(_) => p.is_dir(),
+                };
+                if dir {
                     stack.push(p);
                 } else if p.extension().is_some_and(|x| x == "png")
                     && let Ok(rel) = p.strip_prefix(&base)

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

@@ -144,6 +144,7 @@ type Stream = cpal::Stream;
 type Stream = std::convert::Infallible;
 pub struct Audio {
     _stream: Option<Stream>,
+    device_name: String,
     pub engine: SoundEngine,
     backend: MixerBackend,
     /// Record `Heard` sounds (the subtitle overlay is listening).
@@ -543,15 +544,48 @@ fn build_stream<T: cpal::SizedSample + cpal::FromSample<f32>>(
     )?;
     Ok(stream)
 }
+/// Available audio output device names.
+#[cfg(feature = "audio")]
+pub fn output_devices() -> Vec<String> {
+    if output_disabled(|name| std::env::var_os(name)).is_some() {
+        return Vec::new();
+    }
+    let host = cpal::default_host();
+    let mut names = Vec::new();
+    if let Ok(devices) = host.output_devices() {
+        for device in devices {
+            if let Ok(name) = device.name()
+                && !names.contains(&name)
+            {
+                names.push(name);
+            }
+        }
+    }
+    names
+}
+
+#[cfg(not(feature = "audio"))]
+pub fn output_devices() -> Vec<String> {
+    Vec::new()
+}
+
 impl Audio {
     pub fn new(root: &Path) -> Self {
-        Self::with_output(root, true)
+        Self::with_device(root, "")
+    }
+    pub fn with_device(root: &Path, device_name: &str) -> Self {
+        Self::with_output(root, true, device_name)
     }
     /// No output device: the dedicated server.
     pub fn silent(root: &Path) -> Self {
-        Self::with_output(root, false)
+        Self::with_output(root, false, "")
     }
-    fn with_output(root: &Path, output: bool) -> Self {
+    /// The output device asked for (`soundDevice`), empty for the system's default; the
+    /// default plays when that one can't be opened, as in vanilla.
+    pub fn device(&self) -> &str {
+        &self.device_name
+    }
+    fn with_output(root: &Path, output: bool, target_device: &str) -> Self {
         let registry = SoundRegistry::load(root);
         if output && registry.is_empty() {
             // The game then plays nothing on a working output (#1035, #1076).
@@ -564,7 +598,7 @@ impl Audio {
         }
         let mixer = Arc::new(Mutex::new(Mixer::default()));
         let opened = if output {
-            Self::open(mixer.clone())
+            Self::open_named(mixer.clone(), target_device)
         } else {
             Err("no output on a dedicated server".into())
         };
@@ -581,6 +615,7 @@ impl Audio {
         engine.loaded = live;
         Self {
             _stream: stream,
+            device_name: target_device.to_owned(),
             engine,
             backend: MixerBackend {
                 mixer,
@@ -602,10 +637,61 @@ impl Audio {
         }
     }
     #[cfg(not(feature = "audio"))]
-    fn open(_: Arc<Mutex<Mixer>>) -> Result<Stream> {
+    fn open_named(_: Arc<Mutex<Mixer>>, _: &str) -> Result<Stream> {
         Err("this build has no sound output (built without the `audio` feature)".into())
     }
     #[cfg(feature = "audio")]
+    fn open_named(mixer: Arc<Mutex<Mixer>>, target: &str) -> Result<Stream> {
+        if let Some(reason) = output_disabled(|name| std::env::var_os(name)) {
+            return Err(reason.into());
+        }
+        let host = cpal::default_host();
+        if !target.is_empty()
+            && let Ok(devices) = host.output_devices()
+        {
+            for device in devices {
+                let name = device.name().unwrap_or_else(|_| "unnamed device".into());
+                if name == target {
+                    match open_device(&device, mixer.clone()) {
+                        Ok((stream, config)) => {
+                            log::info!(
+                                "Horizon: audio output {name} ({} Hz, {} channels, {})",
+                                config.sample_rate().0,
+                                config.channels(),
+                                config.sample_format()
+                            );
+                            return Ok(stream);
+                        }
+                        Err(e) => {
+                            log::warn!(
+                                "Horizon: could not open audio device '{target}': {e}; falling back to default"
+                            );
+                        }
+                    }
+                    break;
+                }
+            }
+        }
+        Self::open(mixer)
+    }
+    #[cfg(feature = "audio")]
+    pub fn set_device(&mut self, name: &str) -> Result<()> {
+        if !self.backend.live && self._stream.is_none() && !self.engine.loaded {
+            self.device_name = name.to_owned();
+            return Ok(());
+        }
+        self._stream = Some(Self::open_named(self.backend.mixer.clone(), name)?);
+        self.device_name = name.to_owned();
+        self.backend.live = true;
+        self.engine.loaded = true;
+        Ok(())
+    }
+    #[cfg(not(feature = "audio"))]
+    pub fn set_device(&mut self, name: &str) -> Result<()> {
+        self.device_name = name.to_owned();
+        Ok(())
+    }
+    #[cfg(feature = "audio")]
     fn open(mixer: Arc<Mutex<Mixer>>) -> Result<Stream> {
         if let Some(reason) = output_disabled(|name| std::env::var_os(name)) {
             return Err(reason.into());
@@ -719,11 +805,6 @@ impl Audio {
         self.play(event, at, volume, pitch);
         self.capture = capture;
     }
-    /// `LivingEntity.handleDamageEvent`'s pitch, `(r - r) * 0.2 + 1`, drawn on the
-    /// client (the entity's own random there, never the server's world random).
-    pub fn hurt_pitch(&mut self) -> f32 {
-        (self.random.next_float() - self.random.next_float()) * 0.2 + 1.0
-    }
     /// `AbstractWidget.playButtonClickSound`: an unseeded, relative UI sound.
     pub fn play_button_click(&mut self) {
         self.play_instance(

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

@@ -179,7 +179,7 @@ fn agent() -> ureq::Agent {
 }
 
 /// The discovery document, fetched once per game (a failure is retried next time).
-fn discovery() -> Result<Arc<serde_json::Value>, JoinError> {
+pub(crate) fn discovery() -> Result<Arc<serde_json::Value>, JoinError> {
     static CACHE: Mutex<Option<Arc<serde_json::Value>>> = Mutex::new(None);
     if let Some(d) = CACHE.lock().unwrap().clone() {
         return Ok(d);

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

@@ -0,0 +1,302 @@
+//! Right-to-left text (`FormattedBidiReorder.reorder`, behind
+//! `Language.getVisualOrder`): the logical text a player types becomes the
+//! glyphs a font draws left to right. Arabic letters are shaped into their
+//! joined presentation forms (ICU's `ArabicShaping` with `LETTERS_SHAPE`), the
+//! text is reordered by the Unicode bidirectional algorithm, and characters in
+//! right-to-left runs are mirrored. Left-to-right text comes back unchanged.
+use crate::text::{Span, Text};
+use std::borrow::Cow;
+use unicode_bidi::{
+    BidiClass, Direction, Level, ParagraphBidiInfo, bidi_class, get_base_direction,
+};
+
+/// How a letter joins its neighbours, as ICU's shaper sees it: `Right` joins
+/// the letter before it only, `Dual` both neighbours, `Mark` is skipped over
+/// (diacritics) and `None` never joins.
+#[derive(Clone, Copy, PartialEq)]
+enum Join {
+    None,
+    Right,
+    Dual,
+    Mark,
+}
+use Join::{Dual, Mark, Right};
+
+/// ICU's joining table (`araLink`): code point ranges and their class, with the
+/// lam-alef ligatures at the end. Anything else is `Join::None`.
+const JOINS: &[(u32, u32, Join)] = &[
+    (0x0622, 0x0625, Right),
+    (0x0626, 0x0626, Dual),
+    (0x0627, 0x0627, Right),
+    (0x0628, 0x0628, Dual),
+    (0x0629, 0x0629, Right),
+    (0x062A, 0x062E, Dual),
+    (0x062F, 0x0632, Right),
+    (0x0633, 0x063A, Dual),
+    (0x0640, 0x0647, Dual),
+    (0x0648, 0x0649, Right),
+    (0x064A, 0x064A, Dual),
+    (0x064B, 0x0656, Mark),
+    (0x0670, 0x0670, Mark),
+    (0x0671, 0x0673, Right),
+    (0x0675, 0x0677, Right),
+    (0x0678, 0x0687, Dual),
+    (0x0688, 0x0699, Right),
+    (0x069A, 0x06B9, Dual),
+    (0x06BA, 0x06BA, Right),
+    (0x06BB, 0x06BF, Dual),
+    (0x06C0, 0x06C0, Right),
+    (0x06C1, 0x06C1, Dual),
+    (0x06C2, 0x06CB, Right),
+    (0x06CC, 0x06CC, Dual),
+    (0x06CD, 0x06CD, Right),
+    (0x06CE, 0x06D1, Dual),
+    (0x06D2, 0x06D3, Right),
+    (0x200D, 0x200D, Dual),
+    (0x206D, 0x206F, Mark),
+    (0xFEF5, 0xFEFC, Right),
+];
+
+/// Letters that have joined forms and the code point of the isolated one; the
+/// final, initial and medial forms follow it (a right-joining letter has the
+/// isolated and final only). The lam-alef ligatures are their own letters.
+/// ICU leaves the extended letters (پ چ ژ ک گ ی and the rest of U+0679 to
+/// U+06D3) unchanged, so they are in `JOINS` but not here.
+#[rustfmt::skip]
+const FORMS: &[(u32, u32)] = &[
+    (0x0622, 0xFE81), (0x0623, 0xFE83), (0x0624, 0xFE85), (0x0625, 0xFE87), (0x0626, 0xFE89),
+    (0x0627, 0xFE8D), (0x0628, 0xFE8F), (0x0629, 0xFE93), (0x062A, 0xFE95), (0x062B, 0xFE99),
+    (0x062C, 0xFE9D), (0x062D, 0xFEA1), (0x062E, 0xFEA5), (0x062F, 0xFEA9), (0x0630, 0xFEAB),
+    (0x0631, 0xFEAD), (0x0632, 0xFEAF), (0x0633, 0xFEB1), (0x0634, 0xFEB5), (0x0635, 0xFEB9),
+    (0x0636, 0xFEBD), (0x0637, 0xFEC1), (0x0638, 0xFEC5), (0x0639, 0xFEC9), (0x063A, 0xFECD),
+    (0x0641, 0xFED1), (0x0642, 0xFED5), (0x0643, 0xFED9), (0x0644, 0xFEDD), (0x0645, 0xFEE1),
+    (0x0646, 0xFEE5), (0x0647, 0xFEE9), (0x0648, 0xFEED), (0x0649, 0xFEEF), (0x064A, 0xFEF1),
+    (0xFEF5, 0xFEF5), (0xFEF7, 0xFEF7), (0xFEF9, 0xFEF9), (0xFEFB, 0xFEFB),
+];
+
+/// `Bidi_Mirroring_Glyph` (`UCharacter.getMirror`): each pair is two
+/// neighbouring characters that mirror each other.
+const MIRRORED: &str = "\
+        ()<>[]{}«»༺༻༼༽᚛᚜‹›⁅⁆⁽⁾₍₎∈∋∉∌∊∍∕⧵∟⯾∠⦣∡⦛∢⦠∤⫮∼∽≃⋍≅≌≒≓\
+        ≔≕≤≥≦≧≨≩≪≫≮≯≰≱≲≳≴≵≶≷≸≹≺≻≼≽≾≿⊀⊁⊂⊃⊄⊅⊆⊇⊈⊉⊊⊋⊏⊐⊑⊒⊘⦸⊢⊣⊦⫞\
+        ⊨⫤⊩⫣⊫⫥⊰⊱⊲⊳⊴⊵⊶⊷⊸⟜⋉⋊⋋⋌⋐⋑⋖⋗⋘⋙⋚⋛⋜⋝⋞⋟⋠⋡⋢⋣⋤⋥⋦⋧⋨⋩⋪⋫⋬⋭⋰⋱⋲⋺\
+        ⋳⋻⋴⋼⋶⋽⋷⋾⌈⌉⌊⌋〈〉❨❩❪❫❬❭❮❯❰❱❲❳❴❵⟃⟄⟅⟆⟈⟉⟋⟍⟕⟖⟝⟞⟢⟣⟤⟥⟦⟧⟨⟩⟪⟫\
+        ⟬⟭⟮⟯⦃⦄⦅⦆⦇⦈⦉⦊⦋⦌⦍⦐⦎⦏⦑⦒⦓⦔⦕⦖⦗⦘⦤⦥⦨⦩⦪⦫⦬⦭⦮⦯⧀⧁⧄⧅⧏⧐⧑⧒⧔⧕⧘⧙⧚⧛\
+        ⧨⧩⧸⧹⧼⧽⨫⨬⨭⨮⨴⨵⨼⨽⩤⩥⩹⩺⩻⩼⩽⩾⩿⪀⪁⪂⪃⪄⪅⪆⪇⪈⪉⪊⪋⪌⪍⪎⪏⪐⪑⪒⪓⪔⪕⪖⪗⪘⪙⪚\
+        ⪛⪜⪝⪞⪟⪠⪡⪢⪦⪧⪨⪩⪪⪫⪬⪭⪯⪰⪱⪲⪳⪴⪵⪶⪷⪸⪹⪺⪻⪼⪽⪾⪿⫀⫁⫂⫃⫄⫅⫆⫇⫈⫉⫊⫋⫌⫍⫎⫏⫐\
+        ⫑⫒⫓⫔⫕⫖⫬⫭⫷⫸⫹⫺⸂⸃⸄⸅⸉⸊⸌⸍⸜⸝⸠⸡⸢⸣⸤⸥⸦⸧⸨⸩⹕⹖⹗⹘⹙⹚⹛⹜〈〉《》「」『』【】\
+        〔〕〖〗〘〙〚〛﹙﹚﹛﹜﹝﹞﹤﹥（）＜＞［］｛｝｟｠｢｣";
+
+fn join(c: char) -> Join {
+    let c = c as u32;
+    JOINS
+        .iter()
+        .find(|&&(from, to, _)| (from..=to).contains(&c))
+        .map_or(Join::None, |&(_, _, join)| join)
+}
+
+/// The letter whose joined form `c` is (ICU shapes the forms again), or `c`.
+fn letter_of(c: char) -> char {
+    let c32 = c as u32;
+    if !matches!(c32, 0xFE70..=0xFEFC) {
+        return c;
+    }
+    if (0xFE70..0xFE80).contains(&c32) {
+        // The diacritics' forms pair up from fathatan on.
+        return char::from_u32(0x064B + (c32 - 0xFE70) / 2).unwrap_or(c);
+    }
+    FORMS
+        .iter()
+        .find(|&&(letter, iso)| {
+            let forms = if join(char::from_u32(letter).unwrap_or(c)) == Dual {
+                4
+            } else {
+                2
+            };
+            (iso..iso + forms).contains(&c32)
+        })
+        .and_then(|&(letter, _)| char::from_u32(letter))
+        .unwrap_or(c)
+}
+
+/// `ArabicShaping(LETTERS_SHAPE).shape`: lam followed by an alef (diacritics
+/// may sit between) becomes one ligature, then every letter takes the isolated,
+/// final, initial or medial form its neighbours call for. Diacritics take the
+/// tatweel form between two joined letters. The text can only get shorter.
+fn shape(text: &[char]) -> Vec<char> {
+    let letters: Vec<char> = text.iter().map(|&c| letter_of(c)).collect();
+    let mut chars = Vec::with_capacity(letters.len());
+    let mut i = 0;
+    while i < letters.len() {
+        if letters[i] == '\u{644}' {
+            let mut at = i + 1;
+            while letters.get(at).is_some_and(|&c| join(c) == Mark) {
+                at += 1;
+            }
+            let alef = letters.get(at).and_then(|&c| {
+                ['\u{622}', '\u{623}', '\u{625}', '\u{627}']
+                    .iter()
+                    .position(|&a| a == c)
+            });
+            if let Some(alef) = alef {
+                chars.push(char::from_u32(0xFEF5 + 2 * alef as u32).unwrap_or('\u{644}'));
+                chars.extend_from_slice(&letters[i + 1..at]);
+                i = at + 1;
+                continue;
+            }
+        }
+        chars.push(letters[i]);
+        i += 1;
+    }
+    // Whether the nearest letter before joins the next one, and the joins of
+    // the nearest letter after.
+    let mut joins_next = false;
+    let mut out = Vec::with_capacity(chars.len());
+    for (i, &c) in chars.iter().enumerate() {
+        let next_joins = chars[i + 1..]
+            .iter()
+            .map(|&n| join(n))
+            .find(|&j| j != Mark)
+            .is_some_and(|j| j != Join::None);
+        let kind = join(c);
+        let shaped = match kind {
+            Join::None => {
+                joins_next = false;
+                c
+            }
+            Mark => match c as u32 {
+                m @ 0x064B..=0x0652 => {
+                    let iso = 0xFE70 + 2 * (m - 0x064B);
+                    let tatweel = joins_next && next_joins && !matches!(m, 0x064C | 0x064D);
+                    char::from_u32(iso + u32::from(tatweel)).unwrap_or(c)
+                }
+                _ => c,
+            },
+            Right | Dual => {
+                let to_next = kind == Dual && next_joins;
+                let form = match (joins_next, to_next) {
+                    (false, false) => 0,
+                    (true, false) => 1,
+                    (false, true) => 2,
+                    (true, true) => 3,
+                };
+                joins_next = kind == Dual;
+                FORMS
+                    .binary_search_by_key(&(c as u32), |&(letter, _)| letter)
+                    .ok()
+                    .and_then(|at| char::from_u32(FORMS[at].1 + form))
+                    .unwrap_or(c)
+            }
+        };
+        out.push(shaped);
+    }
+    out
+}
+
+/// `UCharacter.getMirror`.
+fn mirror(c: char) -> char {
+    if bidi_class(c) != BidiClass::ON {
+        return c;
+    }
+    let mut pairs = MIRRORED.chars();
+    while let (Some(a), Some(b)) = (pairs.next(), pairs.next()) {
+        if c == a {
+            return b;
+        }
+        if c == b {
+            return a;
+        }
+    }
+    c
+}
+
+/// Whether a character can change anything: right-to-left letters and numbers,
+/// the explicit direction controls and the diacritics that shaping turns into
+/// letters. Without any, left-to-right text keeps its order.
+fn directional(c: char) -> bool {
+    c as u32 >= 0x0590
+        && (matches!(c as u32, 0x064B..=0x0652)
+            || matches!(
+                bidi_class(c),
+                BidiClass::R
+                    | BidiClass::AL
+                    | BidiClass::AN
+                    | BidiClass::LRE
+                    | BidiClass::RLE
+                    | BidiClass::LRO
+                    | BidiClass::RLO
+                    | BidiClass::PDF
+                    | BidiClass::LRI
+                    | BidiClass::RLI
+                    | BidiClass::FSI
+                    | BidiClass::PDI
+            ))
+}
+
+/// Whether `chars` keep their order and shapes: left-to-right text without
+/// anything directional, in a language that reads left to right by default.
+fn unchanged(mut chars: impl Iterator<Item = char>, default_rtl: bool) -> bool {
+    !default_rtl && !chars.any(directional)
+}
+
+/// `FormattedBidiReorder.reorder`: `chars` shaped, in visual order, with each
+/// character's position in the shaped text. A character's style is the one at
+/// its position in the shaped text, as `SubStringSource` takes it (the text
+/// shrinks at a lam-alef ligature).
+fn reorder(chars: &[char], default_rtl: bool) -> Vec<(char, usize)> {
+    let shaped = shape(chars);
+    let plain: String = shaped.iter().collect();
+    // DEFAULT_RTL only changes text without a strong character.
+    let level =
+        (default_rtl && get_base_direction(plain.as_str()) == Direction::Mixed).then(Level::rtl);
+    let info = ParagraphBidiInfo::new(&plain, level);
+    let levels = info.reordered_levels_per_char(0..plain.len());
+    ParagraphBidiInfo::reorder_visual(&levels)
+        .into_iter()
+        .map(|i| {
+            let c = if levels[i].is_rtl() {
+                mirror(shaped[i])
+            } else {
+                shaped[i]
+            };
+            (c, i)
+        })
+        .collect()
+}
+
+/// `Language.getVisualOrder` of a text (its `§` codes already resolved), for
+/// the current language's direction.
+pub fn visual(text: &Text) -> Cow<'_, Text> {
+    let default_rtl = crate::lang::bidirectional();
+    if unchanged(text.chars().map(|(c, _)| c), default_rtl) {
+        return Cow::Borrowed(text);
+    }
+    let chars: Vec<char> = text.chars().map(|(c, _)| c).collect();
+    let styles: Vec<_> = text.chars().map(|(_, style)| style).collect();
+    let mut out = Text::default();
+    for (c, at) in reorder(&chars, default_rtl) {
+        match out.spans.last_mut() {
+            Some(span) if span.style == *styles[at] => span.text.push(c),
+            _ => out.spans.push(Span {
+                text: c.to_string(),
+                style: styles[at].clone(),
+            }),
+        }
+    }
+    Cow::Owned(out)
+}
+
+/// The same for a plain string.
+pub fn visual_str(s: &str) -> Cow<'_, str> {
+    let default_rtl = crate::lang::bidirectional();
+    if unchanged(s.chars(), default_rtl) {
+        return Cow::Borrowed(s);
+    }
+    let chars: Vec<char> = s.chars().collect();
+    Cow::Owned(
+        reorder(&chars, default_rtl)
+            .into_iter()
+            .map(|(c, _)| c)
+            .collect(),
+    )
+}

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

@@ -1,7 +1,7 @@
 //! Biome colours from the pinned biome definitions and colormaps
 //! (`Biome.getGrassColor`/`getFoliageColor`/..., `BlockTintSources`).
 use crate::Result;
-use horizon_core::{noise::SimplexNoise, random::LegacyRandom};
+use horizon_core::{noise::SimplexNoise, position::BlockPos, random::LegacyRandom};
 use serde_json::Value;
 use std::{collections::HashMap, fs, path::Path};
 
@@ -20,16 +20,77 @@ pub struct SpawnEntry {
     /// A `ConstantInt` count (sampling draws nothing).
     pub constant: bool,
 }
+/// A `natural_mob_spawns` / `spawn_overrides` entry list.
+pub fn parse_entries(list: &Value) -> Vec<SpawnEntry> {
+    list.as_array()
+        .into_iter()
+        .flatten()
+        .filter_map(|e| {
+            let count = &e["count"];
+            let (min, max, constant) = match count {
+                Value::Number(n) => {
+                    let n = n.as_u64().unwrap_or(1) as u32;
+                    (n, n, true)
+                }
+                c if c["type"].as_str() == Some("minecraft:constant") => {
+                    let n = c["value"].as_u64().unwrap_or(1) as u32;
+                    (n, n, true)
+                }
+                c => (
+                    c["min_inclusive"].as_u64().unwrap_or(1) as u32,
+                    c["max_inclusive"].as_u64().unwrap_or(1) as u32,
+                    false,
+                ),
+            };
+            Some(SpawnEntry {
+                entity: e["type"].as_str()?.to_owned(),
+                weight: e["weight"].as_u64().unwrap_or(1) as u32,
+                min,
+                max,
+                constant,
+            })
+        })
+        .collect()
+}
+/// `MobSpawnSettings.MobSpawnCost`.
+#[derive(Clone, Copy, Debug, PartialEq)]
+pub struct SpawnCost {
+    pub energy_budget: f64,
+    pub charge: f64,
+}
+/// The `spawn_costs` of a `natural_mob_spawns` value.
+pub fn parse_costs(costs: &Value) -> HashMap<String, SpawnCost> {
+    costs
+        .as_object()
+        .into_iter()
+        .flatten()
+        .map(|(k, c)| {
+            (
+                k.clone(),
+                SpawnCost {
+                    energy_budget: c["energy_budget"].as_f64().unwrap_or(0.0),
+                    charge: c["charge"].as_f64().unwrap_or(0.0),
+                },
+            )
+        })
+        .collect()
+}
+
 #[derive(Clone, Debug)]
 pub struct BiomeInfo {
     /// `natural_mob_spawns` by category (creature, monster, ...).
     pub spawns: HashMap<String, Vec<SpawnEntry>>,
     /// `natural_mob_spawns` spawn costs by entity type.
-    pub spawn_costs: HashMap<String, crate::mobs::spawn_selection::SpawnCost>,
+    pub spawn_costs: HashMap<String, SpawnCost>,
     /// The `gameplay/creature_world_gen_spawn_probability` attribute.
     pub creature_probability: f32,
+    /// The `gameplay/increased_fire_burnout` attribute (jungles, swamps, peaks,
+    /// mushroom fields).
+    pub increased_fire_burnout: bool,
     pub name: String,
     pub temperature: f32,
+    /// `temperature_modifier: frozen` (the frozen oceans).
+    pub frozen: bool,
     pub downfall: f32,
     pub precipitation: bool,
     pub grass: u32,
@@ -42,6 +103,33 @@ pub struct BiomeInfo {
     pub fog: Option<u32>,
     pub water_fog: u32,
 }
+impl BiomeInfo {
+    /// `Biome.getHeightAdjustedTemperature`: the frozen modifier, then cooler
+    /// with height above `sea_level + 17`.
+    pub fn temperature_at(&self, pos: BlockPos, sea_level: i32) -> f32 {
+        use horizon_world::worldgen::biome_temperature::{
+            BiomeTemperatureSettings, TemperatureModifier,
+        };
+        BiomeTemperatureSettings {
+            base_temperature: self.temperature,
+            modifier: if self.frozen {
+                TemperatureModifier::Frozen
+            } else {
+                TemperatureModifier::None
+            },
+            has_precipitation: self.precipitation,
+            downfall: self.downfall,
+        }
+        .height_adjusted(pos, sea_level)
+    }
+    /// `Biome.getPrecipitationAt` in the Overworld (sea level 63): None
+    /// without precipitation, else whether it falls as snow
+    /// (`getHeightAdjustedTemperature` below 0.15).
+    pub fn snows_at(&self, x: i32, y: i32, z: i32) -> Option<bool> {
+        self.precipitation
+            .then(|| self.temperature_at(BlockPos::new(x, y, z), 63) < 0.15)
+    }
+}
 pub struct Biomes {
     pub list: Vec<BiomeInfo>,
     pub index: HashMap<String, u16>,
@@ -118,17 +206,21 @@ impl Biomes {
             };
             let categories = &natural["spawns_by_category"];
             for (category, entries) in categories.as_object().into_iter().flatten() {
-                let list = crate::mobs::spawn_selection::parse_entries(entries);
+                let list = parse_entries(entries);
                 spawns.insert(category.clone(), list);
             }
             list.push(BiomeInfo {
                 spawns,
-                spawn_costs: crate::mobs::spawn_selection::parse_costs(&natural["spawn_costs"]),
+                spawn_costs: parse_costs(&natural["spawn_costs"]),
                 creature_probability:
                     attributes["minecraft:gameplay/creature_world_gen_spawn_probability"]
                         .as_f64()
                         .unwrap_or(0.1) as f32,
+                increased_fire_burnout: attributes["minecraft:gameplay/increased_fire_burnout"]
+                    .as_bool()
+                    .unwrap_or(false),
                 temperature,
+                frozen: v["temperature_modifier"].as_str() == Some("frozen"),
                 downfall,
                 precipitation: v["has_precipitation"].as_bool().unwrap_or(true),
                 grass: color(&effects["grass_color"])
@@ -164,6 +256,10 @@ impl Biomes {
             .copied()
             .unwrap_or(0)
     }
+    /// Whether the game has the biome `name`.
+    pub fn contains(&self, name: &str) -> bool {
+        self.index.contains_key(name)
+    }
     pub fn get(&self, id: u16) -> &BiomeInfo {
         &self.list[usize::from(id).min(self.list.len() - 1)]
     }

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

@@ -23,9 +23,10 @@
 //! Which states tick is a table by state id, built by the game from the block
 //! registry; whether a slot is made is decided when the slot is promoted at
 //! the start of the next tick, from the block state then.
-use crate::containers::BlockEntity;
+use crate::chunk::block_entity::BlockEntity;
 use crate::fast_hash::{FxHashMap, FxHashSet};
 use std::collections::HashMap;
+use std::sync::Arc;
 
 pub type Pos = (i32, i32, i32);
 
@@ -46,7 +47,7 @@ pub enum Ticking {
 pub struct BlockEntities {
     map: HashMap<Pos, BlockEntity>,
     /// `Level.blockEntityTickers`: positions and the slot each was given.
-    tickers: Vec<(Pos, u32)>,
+    tickers: Arc<Vec<(Pos, u32)>>,
     /// `LevelChunk.tickersInLevel`: the live slot of each ticking position.
     live: FxHashMap<Pos, u32>,
     /// Positions that may need a slot, in the order vanilla would have made
@@ -63,6 +64,10 @@ pub struct BlockEntities {
     /// Positions whose block entity `take` took and `put` has not brought
     /// back.
     out: FxHashSet<Pos>,
+    /// Positions a loaded chunk gave a new block entity over an old one: at
+    /// the next tick their slot stays only if their block state ticks
+    /// (`updateBlockEntityTicker`: rebind, or remove without a ticker).
+    replaced: FxHashSet<Pos>,
     /// `Ticking` by block state id; empty until the game builds it.
     states: Vec<Ticking>,
 }
@@ -233,20 +238,25 @@ impl BlockEntities {
     }
     pub fn clear(&mut self) {
         self.map.clear();
-        self.tickers.clear();
+        self.tickers = Arc::default();
         self.live.clear();
         self.added.clear();
         self.pending.clear();
         self.out.clear();
+        self.replaced.clear();
         self.freed = false;
     }
     /// A loaded or generated chunk's block entities, in the order the chunk
     /// lists them; they tick in its block entity map's order
-    /// (`registerAllBlockEntitiesAfterLevelLoad`).
+    /// (`registerAllBlockEntitiesAfterLevelLoad`). One replacing an entity
+    /// already at its position (`LevelChunk.setBlockEntity`) drops that one;
+    /// its slot is decided by the block state at the next tick.
     pub fn load_chunk(&mut self, entities: Vec<(Pos, BlockEntity)>) {
         let order = chunk_map_order(entities.iter().map(|(p, _)| *p));
         for (p, e) in entities {
-            self.map.insert(p, e);
+            if self.map.insert(p, e).is_some() {
+                self.replaced.insert(p);
+            }
         }
         for p in order {
             self.add(p);
@@ -274,7 +284,7 @@ impl BlockEntities {
     /// and freed ones leave it. `state` reads the block state at a position.
     /// Returns the slots to tick, in order; check each with `is_live` before
     /// ticking it, as the ticks before it can free it.
-    pub fn tickers(&mut self, state: impl Fn(Pos) -> u32) -> Vec<(Pos, u32)> {
+    pub fn tickers(&mut self, state: impl Fn(Pos) -> u32) -> Arc<Vec<(Pos, u32)>> {
         for (pos, token) in std::mem::take(&mut self.added) {
             if self.pending.get(&pos) != Some(&token) {
                 continue;
@@ -288,21 +298,26 @@ impl BlockEntities {
             }
             let slot = self.next();
             self.live.insert(pos, slot);
-            self.tickers.push((pos, slot));
+            Arc::make_mut(&mut self.tickers).push((pos, slot));
+        }
+        for pos in std::mem::take(&mut self.replaced) {
+            if self.live.contains_key(&pos) && self.ticking(state(pos)) != Ticking::Yes {
+                self.cancel(&pos);
+            }
         }
         if !std::mem::take(&mut self.freed) && self.out.is_empty() {
-            return self.tickers.clone();
+            return Arc::clone(&self.tickers);
         }
         self.out.clear();
         let (live, map) = (&mut self.live, &self.map);
-        self.tickers.retain(|(p, slot)| {
+        Arc::make_mut(&mut self.tickers).retain(|(p, slot)| {
             let mine = live.get(p) == Some(slot);
             if mine && !map.contains_key(p) {
                 live.remove(p);
             }
             mine && map.contains_key(p)
         });
-        self.tickers.clone()
+        Arc::clone(&self.tickers)
     }
     /// Whether a slot from `tickers` still ticks.
     pub fn is_live(&self, (pos, slot): (Pos, u32)) -> bool {
@@ -329,8 +344,8 @@ mod tests {
     }
     fn order(b: &mut BlockEntities, states: &HashMap<Pos, u32>) -> Vec<Pos> {
         b.tickers(|p| states.get(&p).copied().unwrap_or(0))
-            .into_iter()
-            .map(|(p, _)| p)
+            .iter()
+            .map(|(p, _)| *p)
             .collect()
     }
 
@@ -389,4 +404,33 @@ mod tests {
         let order = chunk_map_order(many.iter().copied().chain(many.iter().copied()));
         assert_eq!(order.len(), 100);
     }
+
+    /// A chunk loaded over a block entity already there: the new one replaces
+    /// it, and keeps the old slot only while its block state ticks.
+    #[test]
+    fn loaded_chunk_replaces_block_entity_by_state() {
+        let mut b = level();
+        let mut s = HashMap::new();
+        let (p, q) = ((0, 0, 0), (1, 0, 0));
+        for pos in [p, q] {
+            s.insert(pos, 1);
+        }
+        // Two chunks, so the order is the order they load in.
+        b.load_chunk(vec![(p, hopper())]);
+        b.load_chunk(vec![(q, hopper())]);
+        assert_eq!(order(&mut b, &s), [p, q]);
+        // Replaced where the state ticks: the slot stays in its place.
+        b.load_chunk(vec![(p, hopper())]);
+        assert_eq!(order(&mut b, &s), [p, q]);
+        // Replaced where the state has no ticker: the slot is freed, and the
+        // new block entity is the one in the map.
+        s.insert(p, 2);
+        b.load_chunk(vec![(p, BlockEntity::Chest(vec![None; 27]))]);
+        assert_eq!(order(&mut b, &s), [q]);
+        assert!(matches!(b.get(&p), Some(BlockEntity::Chest(items)) if items.len() == 27));
+        // Ticking again later appends it, as any new ticker does.
+        s.insert(p, 1);
+        b.state_changed(p, 2, 1);
+        assert_eq!(order(&mut b, &s), [q, p]);
+    }
 }

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

@@ -435,7 +435,8 @@ pub struct BellTick {
     pub ended: Option<(Vec<([f64; 3], i32)>, Vec<u64>)>,
 }
 
-fn closer_to_center_than(pos: [i32; 3], p: [f64; 3], distance: f64) -> bool {
+/// `Vec3i.closerToCenterThan`: `p` is within `distance` of the block's centre.
+pub fn closer_to_center_than(pos: [i32; 3], p: [f64; 3], distance: f64) -> bool {
     let dx = f64::from(pos[0]) + 0.5 - p[0];
     let dy = f64::from(pos[1]) + 0.5 - p[1];
     let dz = f64::from(pos[2]) + 0.5 - p[2];
@@ -648,6 +649,61 @@ impl Conduit {
     }
 }
 
+/// What `ConduitBlockEntity.serverTick`'s 40-tick check decided.
+#[derive(Clone, Copy, Debug, Default, PartialEq)]
+pub struct ConduitCheck {
+    /// The shape changed: `CONDUIT_ACTIVATE` (true) or `CONDUIT_DEACTIVATE`.
+    pub toggled: Option<bool>,
+    /// The frame blocks counted, while the conduit is active: `applyEffects`
+    /// and `updateAndAttackTarget` follow (the attack needs 42 or more).
+    pub frames: Option<usize>,
+}
+
+/// `ConduitBlockEntity` (server side): what `serverTick` keeps between ticks.
+#[derive(Clone, Debug, Default)]
+pub struct ConduitServer {
+    shape: Conduit,
+    /// `destroyTarget`: the mob id of the enemy being struck.
+    pub target: Option<u32>,
+    next_ambient_sound: i64,
+}
+
+impl ConduitServer {
+    /// The `gameTime % 40` part of `serverTick`: the shape is checked again.
+    pub fn check(
+        &mut self,
+        pos: [i32; 3],
+        game_time: i64,
+        is_water: impl Fn([i32; 3]) -> bool,
+        is_frame: impl Fn([i32; 3]) -> bool,
+    ) -> Option<ConduitCheck> {
+        if game_time % 40 != 0 {
+            return None;
+        }
+        let active = self.shape.update_shape(pos, &is_water, &is_frame);
+        let toggled = (active != self.shape.is_active).then_some(active);
+        self.shape.is_active = active;
+        Some(ConduitCheck {
+            toggled,
+            frames: active.then_some(self.shape.effect_blocks.len()),
+        })
+    }
+    /// The sounds of an active conduit at the end of `serverTick`: whether
+    /// `CONDUIT_AMBIENT` (every 80 ticks) and `CONDUIT_AMBIENT_SHORT` (every
+    /// 60 to 99 ticks) play.
+    pub fn ambient(&mut self, game_time: i64, random: &mut impl RandomSource) -> (bool, bool) {
+        if !self.shape.is_active {
+            return (false, false);
+        }
+        let short = game_time > self.next_ambient_sound;
+        if short {
+            self.next_ambient_sound =
+                game_time + 60 + i64::from(random.next_int_bound(40).unwrap_or(0));
+        }
+        (game_time % 80 == 0, short)
+    }
+}
+
 /// `SkullBlockEntity` animation (client ticker of dragon and piglin heads).
 #[derive(Clone, Copy, Debug, Default, PartialEq)]
 pub struct Skull {
@@ -832,6 +888,8 @@ pub struct BlockEntityAnims {
     pub gateways: FxHashMap<[i32; 3], EndGateway>,
     /// The integrated server's copies of the gateways (`portalTick`).
     pub gateway_servers: FxHashMap<[i32; 3], EndGateway>,
+    /// The integrated server's copies of the conduits (`serverTick`).
+    pub conduit_servers: FxHashMap<[i32; 3], ConduitServer>,
     /// The client level's random (conduit particles).
     pub random: LegacyRandom,
     /// [`Ticker`] by block state id (see [`BlockEntityAnims::classify`]).
@@ -854,6 +912,7 @@ impl Default for BlockEntityAnims {
             pots: FxHashMap::default(),
             gateways: FxHashMap::default(),
             gateway_servers: FxHashMap::default(),
+            conduit_servers: FxHashMap::default(),
             random: LegacyRandom::new(0x6c6576656c),
             kinds: Vec::new(),
             present: Vec::new(),
@@ -909,6 +968,7 @@ impl BlockEntityAnims {
         self.pots.retain(|p, _| keep(*p));
         self.gateways.retain(|p, _| keep(*p));
         self.gateway_servers.retain(|p, _| keep(*p));
+        self.conduit_servers.retain(|p, _| keep(*p));
     }
     /// `getOpenNess(partial)` of the chest or ender chest at `pos`.
     pub fn lid(&self, pos: [i32; 3], partial: f32) -> f32 {

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

@@ -5,7 +5,11 @@
 //! (`entity-models.json`); transforms, animation and textures follow each
 //! vanilla renderer. Faces are lit like the `entity` shader: the lightmap at
 //! the block plus `minecraft_mix_light` with the level's two diffuse lights.
-use crate::{hud::Rect, mesher::Vertex, world::World};
+use crate::{
+    hud::Rect,
+    mesher::{CULL_BACK, Vertex},
+    world::World,
+};
 use glam::{DVec3, Mat4, Quat, Vec3};
 use horizon_core::geometry::{
     Direction,
@@ -93,6 +97,16 @@ pub fn diffuse(normal: Vec3, lights: (Vec3, Vec3)) -> f32 {
 pub fn vertex_light(packed: u8) -> u32 {
     (u32::from(packed >> 4) * 16) | ((u32::from(packed & 15) * 16) << 8)
 }
+/// `ChestRenderer.xmasTextures`: `SpecialDates.isExtendedChristmas` (24 to 26
+/// December in the local time zone), read once when the renderer is created.
+fn extended_christmas() -> bool {
+    use chrono::Datelike;
+    static XMAS: std::sync::OnceLock<bool> = std::sync::OnceLock::new();
+    *XMAS.get_or_init(|| {
+        let now = chrono::Local::now();
+        now.month() == 12 && (24..=26).contains(&now.day())
+    })
+}
 fn pack_color(rgb: u32, alpha: u32, brightness: f32) -> u32 {
     let c = |shift: u32| (((rgb >> shift) & 255) as f32 * brightness) as u32;
     alpha << 24 | c(0) << 16 | c(8) << 8 | c(16)
@@ -149,6 +163,8 @@ pub fn draw_part(
                 layer: 0,
                 color,
                 light,
+
+                glint_uv: [0.0, 0.0],
             });
         }
     }
@@ -581,6 +597,18 @@ fn first_line(line: &str, max_width: f32, advance: &dyn Fn(char) -> f32) -> Stri
     line.to_owned()
 }
 
+/// `AbstractSignRenderer.isOutlineVisible`: the camera within 16 blocks of
+/// the sign's centre.
+fn sign_text_near(pos: [i32; 3], camera: DVec3) -> bool {
+    DVec3::new(
+        f64::from(pos[0]) + 0.5,
+        f64::from(pos[1]) + 0.5,
+        f64::from(pos[2]) + 0.5,
+    )
+    .distance_squared(camera)
+        < 256.0
+}
+
 /// `AbstractSignRenderer.submitSignText`: four centred lines, glowing text
 /// full-bright with an 8x outline in the dark colour.
 fn sign_text_calls(
@@ -610,7 +638,9 @@ fn sign_text_calls(
         .iter()
         .enumerate()
         .map(|(i, line)| {
+            // The line that fits, in the order it is drawn (getVisualOrder).
             let shown = first_line(line, data.max_line_width(), &advance);
+            let shown = crate::bidi::visual_str(&shown).into_owned();
             TextCall {
                 matrix: m,
                 x: -((width(&shown) as i32) / 2) as f32,
@@ -624,10 +654,20 @@ fn sign_text_calls(
         .collect()
 }
 
+/// How far the text of an outlined call sits in front of its outline, in
+/// text units (`Font.DisplayMode.POLYGON_OFFSET`, see `draw_text`).
+const TEXT_OVER_OUTLINE: f32 = 0.05;
+
 /// Draws a text call with the font atlas: 8x8 glyph cells, the outline as
 /// eight one-pixel offsets under the text.
+///
+/// `TextFeatureRenderer.renderText` draws the outline glyphs NORMAL and the
+/// text over them POLYGON_OFFSET, so the coplanar text always wins the depth
+/// test. Here both share one mesh, so the text is lifted a hair towards the
+/// reader instead (a twentieth of a font pixel, invisible) rather than
+/// z-fighting with the outline under it.
 fn draw_text(scene: &Scene, call: &TextCall, out: &mut Vec<Vertex>) {
-    let mut emit = |dx: f32, dy: f32, argb: u32| {
+    let mut emit = |dx: f32, dy: f32, z: f32, argb: u32| {
         let mut x = call.x + dx;
         let y0 = call.y + dy;
         for ch in call.text.chars() {
@@ -642,12 +682,14 @@ fn draw_text(scene: &Scene, call: &TextCall, out: &mut Vec<Vertex>) {
                         normal: [0; 4],
                         pos: call
                             .matrix
-                            .transform_point3(Vec3::new(cx, cy, 0.0))
+                            .transform_point3(Vec3::new(cx, cy, z))
                             .to_array(),
                         uv,
                         layer: 0,
                         color: c,
                         light: call.light,
+
+                        glint_uv: [0.0, 0.0],
                     });
                 }
             }
@@ -665,10 +707,15 @@ fn draw_text(scene: &Scene, call: &TextCall, out: &mut Vec<Vertex>) {
             (0.0, 1.0),
             (1.0, 1.0),
         ] {
-            emit(dx, dy, call.outline);
+            emit(dx, dy, 0.0, call.outline);
         }
     }
-    emit(0.0, 0.0, call.color);
+    let z = if call.outline != 0 {
+        TEXT_OVER_OUTLINE
+    } else {
+        0.0
+    };
+    emit(0.0, 0.0, z, call.color);
 }
 
 /// Block-entity fields the level ticks, at one position (vanilla's own field
@@ -734,9 +781,12 @@ pub struct Scene<'a> {
     /// The skin sprite a `player_head` shows at a position (`SkullBlockRenderer`
     /// profile → skin): a downloaded `skins/<sha1>` slot or the profile's
     /// `DefaultPlayerSkin` fallback; None keeps `SKIN_BY_TYPE` (`DefaultPlayerSkin.getDefaultTexture`, slim steve).
-    pub skull: &'a dyn Fn([i32; 3]) -> Option<&'a str>,
+    pub skull: &'a dyn Fn([i32; 3]) -> Option<String>,
     /// Font glyph cell (none for blank glyphs such as the space) and advance.
     pub glyph: &'a dyn Fn(char) -> (Option<Rect>, f32),
+    /// Changes whenever `glyph` may answer differently (`Font::epoch`): sign
+    /// text laid out under another value is laid out again.
+    pub glyphs: u64,
 }
 
 pub struct BlockEntityRenderer {
@@ -748,7 +798,30 @@ pub struct BlockEntityRenderer {
     pot_patterns: HashMap<String, String>,
     /// `Block.shouldRenderFace` for End gateway faces (its occlusion pair cache needs a lock).
     visibility: Option<Mutex<FaceVisibility>>,
+    sign_texts: Mutex<SignTexts>,
 }
+/// Laid-out sign text by position. `AbstractSignRenderer` lays the text out
+/// again each frame, glyph by glyph; its vertices only change with what is
+/// in the key, so they are kept relative to the block and moved to the camera.
+#[derive(Default)]
+struct SignTexts {
+    signs: crate::fast_hash::FxHashMap<[i32; 3], SignTextEntry>,
+    /// Game time of the last sweep of signs out of view.
+    swept: i64,
+}
+struct SignTextEntry {
+    state: u32,
+    data: crate::signs::SignData,
+    packed: u8,
+    /// Within the glowing text outline's distance (only kept for glowing text).
+    near: bool,
+    glyphs: u64,
+    /// Game time it was last drawn.
+    used: i64,
+    vertices: Vec<Vertex>,
+}
+/// Game ticks a sign's text is kept after it was last drawn.
+const SIGN_TEXT_KEEP: i64 = 100;
 const MODELS: [(&str, &str); 27] = [
     ("chest", "minecraft:chest#main"),
     ("double_chest_left", "minecraft:double_chest_left#main"),
@@ -792,13 +865,23 @@ const VIEW_DISTANCE: f64 = 64.0;
 
 impl BlockEntityRenderer {
     pub fn load(root: &Path, registry: &BlockRegistry) -> crate::Result<Self> {
+        let visibility = crate::models::load_visibility(root, registry)?;
+        Self::load_with_visibility(root, registry, visibility)
+    }
+    /// [`BlockEntityRenderer::load`] over the face visibility the meshes use
+    /// (`MeshTables::visibility`): a clone shares its shapes and their faces.
+    pub fn load_with_visibility(
+        root: &Path,
+        registry: &BlockRegistry,
+        visibility: FaceVisibility,
+    ) -> crate::Result<Self> {
         let all: Value = serde_json::from_slice(&std::fs::read(root.join("entity-models.json"))?)?;
         let models = MODELS
             .iter()
             .filter_map(|(key, layer)| all.get(*layer).map(|v| (*key, ModelPart::parse(v))))
             .collect();
         let mut renderer = Self::new(models, registry);
-        renderer.visibility = Some(Mutex::new(crate::models::load_visibility(root, registry)?));
+        renderer.visibility = Some(Mutex::new(visibility));
         // Sherd items: provides_pottery_pattern -> decorated_pot_pattern asset id.
         if let Ok(bytes) = std::fs::read(root.join("items.json")) {
             let items: Value = serde_json::from_slice(&bytes)?;
@@ -878,6 +961,7 @@ impl BlockEntityRenderer {
             closed_chests,
             pot_patterns: HashMap::new(),
             visibility: None,
+            sign_texts: Mutex::default(),
         }
     }
     fn kind(&self, state: u32) -> &Kind {
@@ -912,11 +996,81 @@ impl BlockEntityRenderer {
             let origin = (DVec3::new(f64::from(pos[0]), f64::from(pos[1]), f64::from(pos[2]))
                 - scene.camera)
                 .as_vec3();
-            let base = Mat4::from_translation(origin);
             let packed = scene.world.light(pos[0], pos[1], pos[2]);
+            if matches!(kind, Kind::Sign { .. }) && scene.texts.is_none() {
+                self.sign_text(scene, *pos, *state, origin, packed, out);
+                continue;
+            }
+            let base = Mat4::from_translation(origin);
             self.render_one(scene, *pos, kind, base, packed, lights, false, true, out);
         }
     }
+    /// A sign's text from the cache, laid out again when its data, light,
+    /// state, outline or font changed.
+    fn sign_text(
+        &self,
+        scene: &Scene,
+        pos: [i32; 3],
+        state: u32,
+        origin: Vec3,
+        packed: u8,
+        out: &mut Vec<Vertex>,
+    ) {
+        let Some(data) = (scene.sign)(pos) else {
+            return;
+        };
+        let near = (data.front.glowing || data.back.glowing) && sign_text_near(pos, scene.camera);
+        let Ok(mut cache) = self.sign_texts.lock() else {
+            return;
+        };
+        let now = scene.game_time;
+        if (now - cache.swept).abs() >= SIGN_TEXT_KEEP {
+            cache.swept = now;
+            cache
+                .signs
+                .retain(|_, e| (now - SIGN_TEXT_KEEP..=now).contains(&e.used));
+        }
+        let glyphs = scene.glyphs;
+        let signs = &mut cache.signs;
+        if !signs.get(&pos).is_some_and(|e| {
+            (e.state, e.packed, e.near, e.glyphs) == (state, packed, near, glyphs)
+                && e.data == *data
+        }) {
+            let mut vertices = signs.remove(&pos).map_or_else(Vec::new, |e| e.vertices);
+            vertices.clear();
+            self.render_one(
+                scene,
+                pos,
+                self.kind(state),
+                Mat4::IDENTITY,
+                packed,
+                diffuse_lights(scene.nether),
+                false,
+                true,
+                &mut vertices,
+            );
+            signs.insert(
+                pos,
+                SignTextEntry {
+                    state,
+                    data: data.clone(),
+                    packed,
+                    near,
+                    glyphs,
+                    used: now,
+                    vertices,
+                },
+            );
+        }
+        let Some(entry) = signs.get_mut(&pos) else {
+            return;
+        };
+        entry.used = now;
+        out.extend(entry.vertices.iter().map(|v| Vertex {
+            pos: (Vec3::from_array(v.pos) + origin).to_array(),
+            ..*v
+        }));
+    }
     /// One block entity at `pos` drawn under `base` with the given packed light
     /// (the parity fixture's entry point).
     pub fn render_block(
@@ -932,6 +1086,30 @@ impl BlockEntityRenderer {
         let lights = diffuse_lights(scene.nether);
         self.render_one(scene, pos, kind, base, packed, lights, false, false, out);
     }
+    /// `TheEndGatewayBlockEntity.shouldRenderFace` for each face of the gateway
+    /// at `pos`: the faces its portal is drawn on.
+    pub fn gateway_faces(
+        &self,
+        world: &World,
+        state: BlockStateId,
+        pos: [i32; 3],
+    ) -> Vec<Direction> {
+        Direction::ALL
+            .into_iter()
+            .filter(|&d| {
+                let [dx, dy, dz] = d.normal();
+                let neighbor = world.block(pos[0] + dx, pos[1] + dy, pos[2] + dz);
+                self.visibility.as_ref().is_none_or(|v| {
+                    v.lock()
+                        .map(|mut v| {
+                            v.should_render_face(state, neighbor, d, true)
+                                .unwrap_or(true)
+                        })
+                        .unwrap_or(true)
+                })
+            })
+            .collect()
+    }
     /// Whether this block state has a block-entity renderer here.
     pub fn renders(&self, state: u32) -> bool {
         !matches!(self.kind(state), Kind::None)
@@ -1124,13 +1302,7 @@ impl BlockEntityRenderer {
                         m *= Mat4::from_translation(Vec3::new(0.0, 1.0 / 3.0, 0.046_666_667))
                             * Mat4::from_scale(s * 0.010_416_667);
                     }
-                    let near = DVec3::new(
-                        f64::from(pos[0]) + 0.5,
-                        f64::from(pos[1]) + 0.5,
-                        f64::from(pos[2]) + 0.5,
-                    )
-                    .distance_squared(scene.camera)
-                        < 256.0;
+                    let near = sign_text_near(pos, scene.camera);
                     let calls = sign_text_calls(scene, data, text, m, packed, near);
                     match scene.texts {
                         Some(sink) => sink.borrow_mut().extend(calls),
@@ -1139,11 +1311,25 @@ impl BlockEntityRenderer {
                 }
             }
             Kind::Chest {
+                block,
                 texture,
                 part,
                 y_rot,
                 ..
             } => {
+                // ChestRenderer.getChestMaterial: normal and trapped chests use the christmas
+                // sprites on 24-26 December. Copper and ender chests keep theirs.
+                let texture = if matches!(block.as_str(), "chest" | "trapped_chest")
+                    && extended_christmas()
+                {
+                    match part {
+                        ChestPart::Single => "entity/chest/christmas",
+                        ChestPart::Left => "entity/chest/christmas_left",
+                        ChestPart::Right => "entity/chest/christmas_right",
+                    }
+                } else {
+                    *texture
+                };
                 let model = match part {
                     ChestPart::Single => "chest",
                     ChestPart::Left => "double_chest_left",
@@ -1286,11 +1472,12 @@ impl BlockEntityRenderer {
                 };
                 // SkullBlockRenderer.getRenderType: the profile's skin when it
                 // resolves, `SKIN_BY_TYPE` (steve) otherwise.
-                let texture = if *kind == SkullType::Player {
-                    (scene.skull)(pos).unwrap_or(texture)
+                let skin = if *kind == SkullType::Player {
+                    (scene.skull)(pos)
                 } else {
-                    texture
+                    None
                 };
+                let texture = skin.as_deref().unwrap_or(texture);
                 let (Some(model), Some(paint)) =
                     (self.models.get(model), paint(texture, 0xFFFFFF, packed))
                 else {
@@ -1385,6 +1572,7 @@ impl BlockEntityRenderer {
                         m *= around(Mat4::from_rotation_y(turn * decay), pivot);
                     }
                 }
+                let first = out.len();
                 if let Some(paint) =
                     paint("entity/decorated_pot/decorated_pot_base", 0xFFFFFF, packed)
                 {
@@ -1402,6 +1590,11 @@ impl BlockEntityRenderer {
                         draw_part(part, side, m, &none, paint, out);
                     }
                 }
+                // `DecoratedPotRenderer` submits every part with `entitySolid`, which culls
+                // back faces: the flat `top` and `bottom` planes show one side each.
+                for vertex in &mut out[first..] {
+                    vertex.normal = CULL_BACK;
+                }
             }
             Kind::EndPortal => {
                 // TheEndPortalRenderer.TRANSFORMATION: y from 6/16 to 12/16; only the
@@ -1432,22 +1625,8 @@ impl BlockEntityRenderer {
                         out,
                     );
                 }
-                // AbstractEndPortalRenderer.extractRenderState: TheEndGatewayBlockEntity.shouldRenderFace.
-                let faces: Vec<Direction> = Direction::ALL
-                    .into_iter()
-                    .filter(|&d| {
-                        let [dx, dy, dz] = d.normal();
-                        let neighbor = scene.world.block(pos[0] + dx, pos[1] + dy, pos[2] + dz);
-                        self.visibility.as_ref().is_none_or(|v| {
-                            v.lock()
-                                .map(|mut v| {
-                                    v.should_render_face(BlockStateId(*state), neighbor, d, true)
-                                        .unwrap_or(true)
-                                })
-                                .unwrap_or(true)
-                        })
-                    })
-                    .collect();
+                // AbstractEndPortalRenderer.extractRenderState.
+                let faces = self.gateway_faces(scene.world, BlockStateId(*state), pos);
                 portal_cube(base, &faces, END_GATEWAY_LAYER, out);
             }
             Kind::Conduit => {
@@ -1714,6 +1893,8 @@ impl BeamPart {
                     layer: 6,
                     color,
                     light: self.wrap,
+
+                    glint_uv: [0.0, 0.0],
                 });
             }
         }
@@ -1784,6 +1965,7 @@ fn portal_cube(m: Mat4, faces: &[Direction], layer: u32, out: &mut Vec<Vertex>)
                 layer,
                 color: 0,
                 light: 0,
+                glint_uv: [0.0, 0.0],
             });
         }
     }
@@ -1900,6 +2082,7 @@ mod tests {
             banner: &|_| Vec::new(),
             skull: &|_| None,
             glyph: &|_| (None, 0.0),
+            glyphs: 0,
         };
         // Compare the cached world path with the original model renderer,
         // including atlas replacement, current light and animated fallback.
@@ -2100,6 +2283,192 @@ mod tests {
         assert_eq!(out[2].uv, [0.5, 0.5]);
     }
 
+    /// TextFeatureRenderer.renderText: an outlined call's text is drawn over
+    /// its outline (Font.DisplayMode.POLYGON_OFFSET), never level with it,
+    /// and plain text stays on the sign's plane.
+    #[test]
+    fn outlined_sign_text_sits_in_front_of_its_outline() {
+        let world = World::new(BlockStateId(0), 1);
+        let sprites = HashMap::new();
+        let glyph = |_: char| {
+            let rect = Rect {
+                u0: 0.0,
+                v0: 0.0,
+                u1: 0.0625,
+                v1: 0.0625,
+                w: 8,
+                h: 8,
+            };
+            (Some(rect), 6.0)
+        };
+        let scene = Scene {
+            camera: DVec3::ZERO,
+            orientation: Quat::IDENTITY,
+            anim: &|_| BlockAnim::default(),
+            texts: None,
+            partial: 0.0,
+            game_time: 0,
+            max_y: 320,
+            world: &world,
+            sprites: &sprites,
+            nether: false,
+            lid: &|_| 0.0,
+            sign: &|_| None,
+            banner: &|_| Vec::new(),
+            skull: &|_| None,
+            glyph: &glyph,
+            glyphs: 0,
+        };
+        let mut call = TextCall {
+            matrix: Mat4::IDENTITY,
+            x: 0.0,
+            y: 0.0,
+            text: "Hi".into(),
+            color: 0xFFFF_FF00,
+            outline: 0xFF33_3300,
+            light: 240 | 240 << 8,
+        };
+        let mut out = Vec::new();
+        draw_text(&scene, &call, &mut out);
+        // Eight outline copies, then the text, four corners a glyph.
+        assert_eq!(out.len(), 9 * 2 * 4);
+        let (outline, text) = out.split_at(8 * 2 * 4);
+        let front = outline.iter().map(|v| v.pos[2]).fold(f32::MIN, f32::max);
+        assert!(
+            text.iter().all(|v| v.pos[2] > front),
+            "text z {:?} not in front of the outline at {front}",
+            text.iter().map(|v| v.pos[2]).collect::<Vec<_>>()
+        );
+        call.outline = 0;
+        out.clear();
+        draw_text(&scene, &call, &mut out);
+        assert_eq!(out.len(), 2 * 4);
+        assert!(out.iter().all(|v| v.pos[2] == 0.0));
+    }
+
+    #[test]
+    fn cached_sign_text_matches_and_follows_changes() {
+        let renderer = BlockEntityRenderer {
+            models: HashMap::new(),
+            kinds: vec![
+                Kind::Sign {
+                    hanging: false,
+                    wall: false,
+                    angle: 180.0,
+                },
+                Kind::Sign {
+                    hanging: true,
+                    wall: true,
+                    angle: 90.0,
+                },
+            ],
+            closed_chests: Default::default(),
+            pot_patterns: HashMap::new(),
+            visibility: None,
+            sign_texts: Mutex::default(),
+        };
+        let world = World::new(BlockStateId(0), 1);
+        let sprites = HashMap::new();
+        let text = |line: &str, glowing| crate::signs::SignText {
+            lines: [line.into(), "two".into(), String::new(), "four".into()],
+            color: 3,
+            glowing,
+            ..Default::default()
+        };
+        let first_text = crate::signs::SignData {
+            front: text("one", false),
+            ..Default::default()
+        };
+        let changed = crate::signs::SignData {
+            front: text("changed", false),
+            ..Default::default()
+        };
+        let glowing = crate::signs::SignData {
+            back: text("glow", true),
+            ..changed.clone()
+        };
+        let wide = std::cell::Cell::new(6.0);
+        let glyph = |c: char| {
+            let u = f32::from(c as u8 % 16) / 16.0;
+            let rect = Rect {
+                u0: u,
+                v0: 0.0,
+                u1: u + 0.0625,
+                v1: 0.0625,
+                w: 8,
+                h: 8,
+            };
+            ((c != ' ').then_some(rect), wide.get())
+        };
+        let (first_sign, changed_sign, glowing_sign) = (
+            |_| Some(&first_text),
+            |_| Some(&changed),
+            |_| Some(&glowing),
+        );
+        let mut scene = Scene {
+            camera: DVec3::new(3.25, 70.5, -4.75),
+            orientation: Quat::IDENTITY,
+            anim: &|_| BlockAnim::default(),
+            texts: None,
+            partial: 0.0,
+            game_time: 0,
+            max_y: 320,
+            world: &world,
+            sprites: &sprites,
+            nether: false,
+            lid: &|_| 0.0,
+            sign: &first_sign,
+            banner: &|_| Vec::new(),
+            skull: &|_| None,
+            glyph: &glyph,
+            glyphs: 0,
+        };
+        let check = |scene: &Scene, pos: [i32; 3], state: u32| {
+            let mut cached = Vec::new();
+            renderer.render(scene, [(pos, state)].iter(), &mut cached);
+            let corner = DVec3::new(f64::from(pos[0]), f64::from(pos[1]), f64::from(pos[2]));
+            let mut original = Vec::new();
+            renderer.render_one(
+                scene,
+                pos,
+                renderer.kind(state),
+                Mat4::from_translation((corner - scene.camera).as_vec3()),
+                world.light(pos[0], pos[1], pos[2]),
+                diffuse_lights(false),
+                false,
+                true,
+                &mut original,
+            );
+            assert!(!cached.is_empty());
+            assert_eq!(cached.len(), original.len());
+            for (a, b) in cached.iter().zip(&original) {
+                assert!((Vec3::from_array(a.pos) - Vec3::from_array(b.pos)).length() < 1e-5);
+                assert_eq!((a.uv, a.color, a.light), (b.uv, b.color, b.light));
+            }
+            cached.len()
+        };
+        let (pos, other) = ([1, 70, 2], [-3, 64, 9]);
+        let first = check(&scene, pos, 0);
+        // The camera moves: the same text, moved.
+        scene.camera.x += 0.5;
+        check(&scene, pos, 0);
+        // New text, glowing text near and far, another state, other glyphs.
+        scene.sign = &changed_sign;
+        assert_ne!(check(&scene, pos, 0), first);
+        scene.sign = &glowing_sign;
+        check(&scene, pos, 0);
+        scene.camera.z -= 20.0;
+        check(&scene, pos, 0);
+        check(&scene, pos, 1);
+        check(&scene, other, 1);
+        wide.set(5.0);
+        scene.glyphs = 1;
+        check(&scene, pos, 1);
+        // Signs out of view for a while are dropped.
+        scene.game_time = 2 * SIGN_TEXT_KEEP;
+        check(&scene, pos, 0);
+        assert_eq!(renderer.sign_texts.lock().unwrap().signs.len(), 1);
+    }
     #[test]
     fn first_line_wraps_on_bytes_without_splitting_a_char() {
         let advance = |c: char| if c == ' ' { 4.0 } else { 6.0 };
@@ -2108,4 +2477,71 @@ mod tests {
         assert_eq!(first_line("\u{6771}", 3.0, &advance), "\u{6771}");
         assert_eq!(first_line("ab\ncd", 100.0, &advance), "ab");
     }
+    /// `DecoratedPotRenderer` submits every part with `RenderTypes.entitySolid`,
+    /// whose pipeline culls back faces. The pot's `top` and `bottom` are flat
+    /// boxes, so without that cull both sides of each plane are drawn and they
+    /// z-fight: the pot renders wrong.
+    #[test]
+    fn the_decorated_pot_culls_its_back_faces() {
+        let root = std::path::PathBuf::from(env!("CARGO_MANIFEST_DIR"))
+            .join("../../.local/horizon-client")
+            .join(horizon_core::VANILLA_VERSION);
+        if !root.join("entity-models.json").exists() {
+            return;
+        }
+        let assets = crate::assets::Assets::load(&root).unwrap();
+        let registry = assets.registry;
+        let renderer = BlockEntityRenderer::load(&root, registry).unwrap();
+        let state = registry.default_state("minecraft:decorated_pot").unwrap();
+        let sprites: HashMap<String, Rect> = [
+            "entity/decorated_pot/decorated_pot_base",
+            "entity/decorated_pot/decorated_pot_side",
+        ]
+        .into_iter()
+        .map(|name| {
+            (
+                name.to_owned(),
+                Rect {
+                    u0: 0.25,
+                    v0: 0.125,
+                    u1: 0.375,
+                    v1: 0.25,
+                    w: 16,
+                    h: 16,
+                },
+            )
+        })
+        .collect();
+        let world = World::new(BlockStateId(0), 1);
+        let scene = Scene {
+            camera: DVec3::ZERO,
+            orientation: Quat::IDENTITY,
+            anim: &|_| BlockAnim::default(),
+            texts: None,
+            partial: 0.5,
+            game_time: 0,
+            max_y: 320,
+            world: &world,
+            sprites: &sprites,
+            nether: false,
+            lid: &|_| 0.0,
+            sign: &|_| None,
+            banner: &|_| Vec::new(),
+            skull: &|_| None,
+            glyph: &|_| (None, 0.0),
+            glyphs: 0,
+        };
+        let mut verts = Vec::new();
+        renderer.render_block(&scene, [0; 3], state.0, Mat4::IDENTITY, 0xff, &mut verts);
+        // Vanilla submits 28 quads for a plain pot, and the cull keeps them all.
+        assert_eq!(
+            verts.len() / 4,
+            28,
+            "the pot submits all of vanilla's quads"
+        );
+        assert!(
+            verts.iter().all(|v| v.normal == CULL_BACK),
+            "entitySolid culls the pot's back faces"
+        );
+    }
 }

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

@@ -49,6 +49,8 @@ pub fn geometry(
                     color: 0xffff_ffff,
                     light: stage_light(stage),
                     normal: [0; 4],
+
+                    glint_uv: [0.0, 0.0],
                 });
             }
         }

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

@@ -2,247 +2,31 @@
 //! in vanilla, ported as tables), data-driven `minecraft:brewing` recipes from
 //! `data/minecraft/recipe/brewing`, potion colours and tooltips, and
 //! `BrewingStandBlockEntity.serverTick`.
+pub use crate::chunk::block_entity::BrewingStand;
 use crate::{
-    containers::Providers,
     items::{ItemStack, Items},
+    providers::Providers,
 };
 use serde_json::Value;
-use std::{collections::HashSet, fs, path::Path, sync::Arc};
+use std::{collections::HashSet, fs, path::Path};
 
-#[derive(Clone, Copy, Debug, PartialEq, Eq)]
-pub enum Category {
-    Beneficial,
-    Harmful,
-    Neutral,
-}
-/// A `MobEffect`: id (without namespace), colour, category, instantaneous.
-#[derive(Clone, Copy, Debug)]
-pub struct EffectDef {
-    pub id: &'static str,
-    pub color: u32,
-    pub category: Category,
-    pub instant: bool,
-}
-const fn fx(id: &'static str, color: u32, category: Category) -> EffectDef {
-    EffectDef {
-        id,
-        color,
-        category,
-        instant: false,
-    }
-}
-use Category::{Beneficial as B, Harmful as H, Neutral as N};
-/// `MobEffects` in registration order.
-pub const EFFECTS: &[EffectDef] = &[
-    fx("speed", 3402751, B),
-    fx("slowness", 9154528, H),
-    fx("haste", 14270531, B),
-    fx("mining_fatigue", 4866583, H),
-    fx("strength", 16762624, B),
-    EffectDef {
-        id: "instant_health",
-        color: 16262179,
-        category: B,
-        instant: true,
-    },
-    EffectDef {
-        id: "instant_damage",
-        color: 11101546,
-        category: H,
-        instant: true,
-    },
-    fx("jump_boost", 16646020, B),
-    fx("nausea", 5578058, H),
-    fx("regeneration", 13458603, B),
-    fx("resistance", 9520880, B),
-    fx("fire_resistance", 16750848, B),
-    fx("water_breathing", 10017472, B),
-    fx("invisibility", 16185078, B),
-    fx("blindness", 2039587, H),
-    fx("night_vision", 12779366, B),
-    fx("hunger", 5797459, H),
-    fx("weakness", 4738376, H),
-    fx("poison", 8889187, H),
-    fx("wither", 7561558, H),
-    fx("health_boost", 16284963, B),
-    fx("absorption", 2445989, B),
-    EffectDef {
-        id: "saturation",
-        color: 16262179,
-        category: B,
-        instant: true,
-    },
-    fx("glowing", 9740385, N),
-    fx("levitation", 13565951, H),
-    fx("luck", 5882118, B),
-    fx("unluck", 12624973, H),
-    fx("slow_falling", 15978425, B),
-    fx("conduit_power", 1950417, B),
-    fx("dolphins_grace", 8954814, B),
-    fx("bad_omen", 745784, N),
-    fx("hero_of_the_village", 4521796, B),
-    fx("darkness", 2696993, H),
-    fx("trial_omen", 1484454, N),
-    fx("raid_omen", 14565464, N),
-    fx("wind_charged", 12438015, H),
-    fx("weaving", 7891290, H),
-    fx("oozing", 10092451, H),
-    fx("infested", 9214860, H),
-    fx("breath_of_the_nautilus", 65518, B),
-];
-pub fn effect(id: &str) -> Option<&'static EffectDef> {
-    let id = id.trim_start_matches("minecraft:");
-    EFFECTS.iter().find(|e| e.id == id)
-}
-/// A `Potion`: id, name suffix (`item.minecraft.potion.effect.<name>`) and
-/// effects as (effect, duration ticks, amplifier).
-#[derive(Clone, Copy, Debug)]
-pub struct PotionDef {
-    pub id: &'static str,
-    pub name: &'static str,
-    pub effects: &'static [(&'static str, i32, i32)],
-}
-const fn p(
-    id: &'static str,
-    name: &'static str,
-    effects: &'static [(&'static str, i32, i32)],
-) -> PotionDef {
-    PotionDef { id, name, effects }
-}
-/// `Potions` in registration order.
-pub const POTIONS: &[PotionDef] = &[
-    p("water", "water", &[]),
-    p("mundane", "mundane", &[]),
-    p("thick", "thick", &[]),
-    p("awkward", "awkward", &[]),
-    p("night_vision", "night_vision", &[("night_vision", 3600, 0)]),
-    p(
-        "long_night_vision",
-        "night_vision",
-        &[("night_vision", 9600, 0)],
-    ),
-    p("invisibility", "invisibility", &[("invisibility", 3600, 0)]),
-    p(
-        "long_invisibility",
-        "invisibility",
-        &[("invisibility", 9600, 0)],
-    ),
-    p("leaping", "leaping", &[("jump_boost", 3600, 0)]),
-    p("long_leaping", "leaping", &[("jump_boost", 9600, 0)]),
-    p("strong_leaping", "leaping", &[("jump_boost", 1800, 1)]),
-    p(
-        "fire_resistance",
-        "fire_resistance",
-        &[("fire_resistance", 3600, 0)],
-    ),
-    p(
-        "long_fire_resistance",
-        "fire_resistance",
-        &[("fire_resistance", 9600, 0)],
-    ),
-    p("swiftness", "swiftness", &[("speed", 3600, 0)]),
-    p("long_swiftness", "swiftness", &[("speed", 9600, 0)]),
-    p("strong_swiftness", "swiftness", &[("speed", 1800, 1)]),
-    p("slowness", "slowness", &[("slowness", 1800, 0)]),
-    p("long_slowness", "slowness", &[("slowness", 4800, 0)]),
-    p("strong_slowness", "slowness", &[("slowness", 400, 3)]),
-    p(
-        "turtle_master",
-        "turtle_master",
-        &[("slowness", 400, 3), ("resistance", 400, 2)],
-    ),
-    p(
-        "long_turtle_master",
-        "turtle_master",
-        &[("slowness", 800, 3), ("resistance", 800, 2)],
-    ),
-    p(
-        "strong_turtle_master",
-        "turtle_master",
-        &[("slowness", 400, 5), ("resistance", 400, 3)],
-    ),
-    p(
-        "water_breathing",
-        "water_breathing",
-        &[("water_breathing", 3600, 0)],
-    ),
-    p(
-        "long_water_breathing",
-        "water_breathing",
-        &[("water_breathing", 9600, 0)],
-    ),
-    p("healing", "healing", &[("instant_health", 1, 0)]),
-    p("strong_healing", "healing", &[("instant_health", 1, 1)]),
-    p("harming", "harming", &[("instant_damage", 1, 0)]),
-    p("strong_harming", "harming", &[("instant_damage", 1, 1)]),
-    p("poison", "poison", &[("poison", 900, 0)]),
-    p("long_poison", "poison", &[("poison", 1800, 0)]),
-    p("strong_poison", "poison", &[("poison", 432, 1)]),
-    p("regeneration", "regeneration", &[("regeneration", 900, 0)]),
-    p(
-        "long_regeneration",
-        "regeneration",
-        &[("regeneration", 1800, 0)],
-    ),
-    p(
-        "strong_regeneration",
-        "regeneration",
-        &[("regeneration", 450, 1)],
-    ),
-    p("strength", "strength", &[("strength", 3600, 0)]),
-    p("long_strength", "strength", &[("strength", 9600, 0)]),
-    p("strong_strength", "strength", &[("strength", 1800, 1)]),
-    p("weakness", "weakness", &[("weakness", 1800, 0)]),
-    p("long_weakness", "weakness", &[("weakness", 4800, 0)]),
-    p("luck", "luck", &[("luck", 6000, 0)]),
-    p("slow_falling", "slow_falling", &[("slow_falling", 1800, 0)]),
-    p(
-        "long_slow_falling",
-        "slow_falling",
-        &[("slow_falling", 4800, 0)],
-    ),
-    p("wind_charged", "wind_charged", &[("wind_charged", 3600, 0)]),
-    p("weaving", "weaving", &[("weaving", 3600, 0)]),
-    p("oozing", "oozing", &[("oozing", 3600, 0)]),
-    p("infested", "infested", &[("infested", 3600, 0)]),
-];
-pub fn potion(id: &str) -> Option<&'static PotionDef> {
-    let id = id.trim_start_matches("minecraft:");
-    POTIONS.iter().find(|p| p.id == id)
-}
-/// `PotionContents.BASE_POTION_COLOR` (ARGB -13083194) as RGB.
-pub const BASE_POTION_COLOR: u32 = 0x385DC6;
-/// `PotionContents.getColor`: amplifier-weighted mix of visible effect colours.
-pub fn potion_color(id: Option<&str>) -> u32 {
-    let Some(def) = id.and_then(potion) else {
-        return BASE_POTION_COLOR;
-    };
-    let (mut r, mut g, mut b, mut total) = (0u32, 0u32, 0u32, 0u32);
-    for (e, _, amp) in def.effects {
-        let Some(e) = effect(e) else { continue };
-        let w = *amp as u32 + 1;
-        r += w * (e.color >> 16 & 255);
-        g += w * (e.color >> 8 & 255);
-        b += w * (e.color & 255);
-        total += w;
-    }
-    match (
-        r.checked_div(total),
-        g.checked_div(total),
-        b.checked_div(total),
-    ) {
-        (Some(r), Some(g), Some(b)) => (r << 16) | (g << 8) | b,
-        _ => BASE_POTION_COLOR,
-    }
-}
-/// `MobEffectUtil.formatDuration` at 20 TPS: m:ss or h:mm:ss.
+pub use horizon_client_core::potions::{
+    BASE_POTION_COLOR, Category, EFFECTS, EffectDef, POTIONS, PotionDef, effect, namespaced,
+    potion, potion_color,
+};
+/// `MobEffectUtil.formatDuration` at 20 TPS.
 pub fn format_duration(ticks: i32) -> String {
-    let secs = ticks / 20;
+    format_tick_duration(ticks, 20.0)
+}
+/// `StringUtil.formatTickDuration`: mm:ss, or hh:mm:ss from an hour up, every
+/// field two digits.
+pub fn format_tick_duration(ticks: i32, tick_rate: f32) -> String {
+    let secs = (ticks as f32 / tick_rate).floor() as i32;
     let (h, m, s) = (secs / 3600, secs / 60 % 60, secs % 60);
     if h > 0 {
-        format!("{h}:{m:02}:{s:02}")
+        format!("{h:02}:{m:02}:{s:02}")
     } else {
-        format!("{m}:{s:02}")
+        format!("{m:02}:{s:02}")
     }
 }
 /// `item.minecraft.potion.effect.<name>` style translation key for a potion item.
@@ -266,20 +50,30 @@ pub fn tooltip(
             Category::Neutral,
         )];
     }
-    def.effects
-        .iter()
+    effect_lines(def.effects.iter().copied(), scale, translate)
+}
+/// `PotionContents.addPotionTooltip`'s line per effect: its name, potency and
+/// scaled duration, for (effect id, duration, amplifier) entries.
+pub fn effect_lines<'a>(
+    effects: impl IntoIterator<Item = (&'a str, i32, i32)>,
+    scale: f32,
+    translate: &dyn Fn(&str) -> Option<String>,
+) -> Vec<(String, Category)> {
+    effects
+        .into_iter()
         .map(|(e, duration, amp)| {
+            let e = e.trim_start_matches("minecraft:");
             let mut line =
-                translate(&format!("effect.minecraft.{e}")).unwrap_or_else(|| (*e).to_owned());
-            if *amp > 0 {
+                translate(&format!("effect.minecraft.{e}")).unwrap_or_else(|| e.to_owned());
+            if amp > 0 {
                 line.push(' ');
                 line.push_str(
                     &translate(&format!("potion.potency.{amp}"))
-                        .unwrap_or_else(|| crate::enchant::level_name(*amp as u32 + 1)),
+                        .unwrap_or_else(|| crate::enchant::level_name(amp as u32 + 1)),
                 );
             }
             let instant = effect(e).is_some_and(|d| d.instant);
-            let scaled = (*duration as f32 * scale) as i32;
+            let scaled = (duration as f32 * scale) as i32;
             if !instant && scaled > 20 {
                 line = format!("{line} ({})", format_duration(scaled));
             }
@@ -412,18 +206,6 @@ impl Brewing {
     }
 }
 
-/// `BrewingStandBlockEntity` state. Slots: 0-2 bottles, 3 ingredient, 4 fuel.
-#[derive(Clone, Debug, Default)]
-pub struct BrewingStand {
-    pub items: [Option<ItemStack>; 5],
-    pub brew_time: i32,
-    pub total_brew_time: i32,
-    pub fuel: i32,
-    pub total_fuel: i32,
-    pub speed: f32,
-    pub ingredient: Option<Arc<str>>,
-    pub last_bottles: Option<[bool; 3]>,
-}
 /// What a brewing tick asks the world to do.
 #[derive(Clone, Debug, Default, PartialEq)]
 pub struct BrewTick {
@@ -550,10 +332,14 @@ mod tests {
             potion_name_key("minecraft:splash_potion", Some("minecraft:long_swiftness")),
             "item.minecraft.splash_potion.effect.swiftness"
         );
-        assert_eq!(format_duration(9600), "8:00");
-        assert_eq!(format_duration(450), "0:22");
+        assert_eq!(format_duration(9600), "08:00");
+        assert_eq!(format_duration(450), "00:22");
+        assert_eq!(format_duration(140), "00:07");
+        assert_eq!(format_duration(1800), "01:30");
+        assert_eq!(format_duration(72000), "01:00:00");
+        assert_eq!(format_tick_duration(9600, 40.0), "04:00");
         let t = tooltip(Some("minecraft:strong_poison"), 1.0, &|_| None);
-        assert_eq!(t[0].0, "poison II (0:21)");
+        assert_eq!(t[0].0, "poison II (00:21)");
         assert_eq!(POTIONS.len(), 46);
     }
 
@@ -610,4 +396,23 @@ mod tests {
         stand.tick(&brewing, &items, &providers);
         assert_eq!(stand.brew_time, 0);
     }
+
+    /// #3312: `PotionContents.getPotionDescription` names the effects with
+    /// translatable components, so a Russian game reads them from ru_ru.json
+    /// (the prepared one; skipped without it), as the tooltip's other lines.
+    #[test]
+    fn effect_lines_read_the_selected_language() {
+        let root = std::path::PathBuf::from(env!("CARGO_MANIFEST_DIR"))
+            .join("../../.local/horizon-client")
+            .join(horizon_core::VANILLA_VERSION);
+        if !root.join("assets/minecraft/lang/ru_ru.json").exists() {
+            return;
+        }
+        let ru = crate::lang::Language::load(&[&root], "ru_ru");
+        let translate = |key: &str| ru.get(key).map(str::to_owned);
+        let lines = tooltip(Some("minecraft:turtle_master"), 0.125, &translate);
+        assert_eq!(lines.len(), 2);
+        assert!(lines[0].0.starts_with("Замедление IV ("), "{lines:?}");
+        assert!(lines[1].0.starts_with("Сопротивление III ("), "{lines:?}");
+    }
 }

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

@@ -653,18 +653,57 @@ pub fn modify_fov_based_on_death_or_fluid(
     fov
 }
 
-/// `ClientAvatarState`: the walked distance and view bob of a player.
+/// `ClientAvatarState`: the walked distance, view bob and cloak of a player.
 #[derive(Clone, Copy, Debug, Default, PartialEq)]
 pub struct AvatarBob {
     pub walk_dist: f32,
     pub walk_dist_o: f32,
     pub bob: f32,
     pub bob_o: f32,
+    /// `xCloak`, `yCloak`, `zCloak`: a point trailing the player, which the cape leans from.
+    pub cloak: [f64; 3],
+    pub cloak_o: [f64; 3],
 }
 impl AvatarBob {
-    /// `ClientAvatarState.tick` (at the start of `AbstractClientPlayer.tick`).
-    pub fn tick(&mut self) {
+    /// `ClientAvatarState.tick` (at the start of `AbstractClientPlayer.tick`)
+    /// with the player's position then: `moveCloak` eases the cloak a quarter
+    /// of the way there, or puts it there from 10 blocks away.
+    pub fn tick(&mut self, position: [f64; 3]) {
         self.walk_dist_o = self.walk_dist;
+        self.cloak_o = self.cloak;
+        for i in 0..3 {
+            let d = position[i] - self.cloak[i];
+            if d > 10.0 || d < -10.0 {
+                self.cloak[i] = position[i];
+                self.cloak_o[i] = position[i];
+            } else {
+                self.cloak[i] += d * 0.25;
+            }
+        }
+    }
+    /// `AvatarRenderer.extractCapeState`: the cape's `capeFlap`, `capeLean`
+    /// and `capeLean2` (degrees) for the player at `position` (interpolated)
+    /// with its body turned `body_yaw` and its `fallFlyingScale`.
+    pub fn cape(
+        &self,
+        partial: f32,
+        position: [f64; 3],
+        body_yaw: f32,
+        fall_flying_scale: f32,
+    ) -> [f32; 3] {
+        let d: [f64; 3] = std::array::from_fn(|i| {
+            lerp_d(f64::from(partial), self.cloak_o[i], self.cloak[i]) - position[i]
+        });
+        let rad = f64::from(body_yaw * DEG_TO_RAD);
+        let (sin, cos) = (f64::from(trig::sin(rad)), f64::from(-trig::cos(rad)));
+        let mut flap = (d[1] as f32 * 10.0).clamp(-6.0, 32.0);
+        let lean = ((d[0] * sin + d[2] * cos) as f32 * 100.0 * (1.0 - fall_flying_scale))
+            .clamp(0.0, 150.0);
+        let lean2 = ((d[0] * cos - d[2] * sin) as f32 * 100.0).clamp(-20.0, 20.0);
+        let bob = self.interpolated_bob(partial);
+        let walk = lerp(partial, self.walk_dist_o, self.walk_dist);
+        flap += trig::sin(f64::from(walk * 6.0)) * 32.0 * bob;
+        [flap, lean, lean2]
     }
     /// `LocalPlayer.move`: `addWalkedDistance(Mth.length(dx, dz) * 0.6F)`
     /// with the float horizontal displacement.
@@ -772,8 +811,46 @@ pub fn bob_matrix(state: &BobState, damage_tilt_strength: f64, bob_view_option:
     pose
 }
 
+/// The spinning effect `GameRenderer.renderLevel` multiplies into the level's
+/// projection after the bob: a skew about a tilted axis, from a portal's or
+/// Nausea's intensity (already scaled by Distortion Effects) and the angle in
+/// degrees. The first-person hand keeps its own projection without it.
+pub fn spinning_effect_matrix(intensity: f32, angle_degrees: f32) -> glam::Mat4 {
+    if intensity <= 0.0 {
+        return glam::Mat4::IDENTITY;
+    }
+    let mut skew = 5.0 / (intensity * intensity + 5.0) - intensity * 0.04;
+    skew *= skew;
+    let axis = glam::Vec3::new(
+        0.0,
+        std::f32::consts::SQRT_2 / 2.0,
+        std::f32::consts::SQRT_2 / 2.0,
+    );
+    let angle = angle_degrees * DEG_TO_RAD;
+    glam::Mat4::from_axis_angle(axis, angle)
+        * glam::Mat4::from_scale(glam::Vec3::new(1.0 / skew, 1.0, 1.0))
+        * glam::Mat4::from_axis_angle(axis, -angle)
+}
+
 #[cfg(test)]
 mod tests {
+    /// `moveCloak` trails a quarter of the way, jumps from 10 blocks away; the
+    /// cape leans back as the player walks forward (south, body yaw 0).
+    #[test]
+    fn the_cloak_trails_the_player() {
+        let mut a = super::AvatarBob::default();
+        a.tick([0.0, 64.0, 0.0]);
+        assert_eq!((a.cloak, a.cloak_o), ([0.0, 64.0, 0.0], [0.0, 64.0, 0.0]));
+        a.tick([0.0, 64.0, 1.0]);
+        assert_eq!(a.cloak, [0.0, 64.0, 0.25]);
+        let [flap, lean, lean2] = a.cape(1.0, [0.0, 64.0, 1.0], 0.0, 0.0);
+        assert_eq!((flap, lean, lean2), (0.0, 75.0, 0.0));
+        // Falling lifts the flap, at most 32 degrees.
+        assert_eq!(a.cape(1.0, [0.0, 60.0, 0.25], 0.0, 0.0)[0], 32.0);
+        // Gliding takes the lean away.
+        assert_eq!(a.cape(1.0, [0.0, 64.0, 1.0], 0.0, 1.0)[1], 0.0);
+    }
+
     #[test]
     fn depth_far_covers_the_cloud_range() {
         // renderDistance 2 with the default Cloud Distance (128 chunks).

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

@@ -16,6 +16,9 @@ use crate::{
 #[path = "chat_tests.rs"]
 mod tests;
 
+/// `CommandHistory.PERSISTED_COMMANDS_FILE_NAME` and its size cap.
+const COMMAND_HISTORY_FILE: &str = "command_history.txt";
+const MAX_PERSISTED_COMMAND_HISTORY: usize = 50;
 /// GuiMessageTag.systemSinglePlayer's indicator colour.
 pub const SYSTEM_INDICATOR: u32 = 0xD0D0D0;
 
@@ -80,6 +83,10 @@ impl ChatAbilities {
             ChatSource::Client => true,
         }
     }
+    /// `ChatAbilities.hasAnyRestrictions`: the Chat option takes something.
+    pub fn any_restriction(&self) -> bool {
+        *self != Self::new(ChatVisibility::Full)
+    }
     /// Whether the chat screen may send `input` (`hasAllowedInput`).
     pub fn allows(&self, input: &str) -> bool {
         if input.starts_with('/') {
@@ -185,6 +192,10 @@ pub struct Chat {
     lines: Vec<Line>,
     /// Sent messages and commands (ChatComponent.recentChat).
     pub recent: Vec<String>,
+    /// `CommandHistory`: the last commands, kept in `command_history.txt`
+    /// in the game folder once `load_history` has set it.
+    commands: Vec<String>,
+    history_file: Option<std::path::PathBuf>,
     scroll: usize,
     new_since_scroll: bool,
     pub options: ChatOptions,
@@ -310,6 +321,17 @@ impl Chat {
         self.lines.clear();
         self.scroll = 0;
     }
+    /// `new CommandHistory(gameFolder)`: the commands kept from earlier runs
+    /// start the chat's history (`ChatComponent`'s constructor).
+    pub fn load_history(&mut self, game_folder: &std::path::Path) {
+        let file = game_folder.join(COMMAND_HISTORY_FILE);
+        if let Ok(text) = std::fs::read_to_string(&file) {
+            self.commands = text.lines().map(str::to_owned).collect();
+            self.recent.extend(self.commands.iter().cloned());
+        }
+        self.history_file = Some(file);
+    }
+    /// `ChatComponent.addRecentChat`: a command also goes to the saved history.
     pub fn add_recent(&mut self, message: &str) {
         if self.recent.last().map(String::as_str) != Some(message) {
             if self.recent.len() >= 100 {
@@ -317,6 +339,21 @@ impl Chat {
             }
             self.recent.push(message.to_owned());
         }
+        if message.starts_with('/') && self.commands.last().map(String::as_str) != Some(message) {
+            if self.commands.len() >= MAX_PERSISTED_COMMAND_HISTORY {
+                self.commands.remove(0);
+            }
+            self.commands.push(message.to_owned());
+            if let Some(file) = &self.history_file {
+                let mut text = self.commands.join("\n");
+                text.push('\n');
+                if let Err(e) = std::fs::write(file, text) {
+                    log::error!(
+                        "Failed to write {COMMAND_HISTORY_FILE}, command history will be missing: {e}"
+                    );
+                }
+            }
+        }
     }
     pub fn reset_scroll(&mut self) {
         self.scroll = 0;
@@ -438,10 +475,71 @@ impl Chat {
         out.push(GuiDraw::Pop);
         out
     }
-    /// Draws [`Chat::layout`] into the HUD batch.
+    /// Draws [`Chat::layout`] into the HUD batch, and with the chat screen
+    /// open the restricted prompt above the lines.
     pub fn draw(&self, batch: &mut HudBatch, atlas: &HudAtlas, ticks: u64, focused: bool) {
         let draws = self.layout(batch.height as i32, ticks, focused);
         hud_layout::paint(batch, atlas, &draws);
+        if focused && self.abilities.any_restriction() {
+            let prompt = self.restricted_prompt(&atlas.font, batch.height as i32);
+            hud_layout::paint(batch, atlas, &prompt);
+        }
+    }
+    /// `ChatComponent.extractRenderState` for `FOREGROUND_RESTRICTED`: a
+    /// background row and the red, underlined "Chat is restricted" line in
+    /// the row above the messages, clipped to the chat's width.
+    fn restricted_prompt(&self, font: &crate::font::Font, height: i32) -> Vec<GuiDraw> {
+        let o = &self.options;
+        let scale = o.scale as f32;
+        let max_width = hud_layout::ceil(o.width_px() as f32 / scale);
+        let chat_bottom = hud_layout::floor((height - 40) as f32 / scale);
+        let entry_height = o.line_height();
+        let bottom_to_text =
+            (8.0 * (o.line_spacing + 1.0) - 4.0 * o.line_spacing + 0.5).floor() as i32;
+        let shown = self
+            .lines
+            .len()
+            .saturating_sub(self.scroll)
+            .min(self.lines_per_page(true));
+        let top = chat_bottom - (shown as i32 + 1) * entry_height;
+        let mut prompt = Text::translate("chat_screen.restricted", &[]).with_style(&Style {
+            color: Some(text::RED),
+            underlined: Some(true),
+            ..Style::default()
+        });
+        // ComponentRenderUtils.clipText.
+        let mut width = 0.0;
+        let fits = prompt
+            .chars()
+            .take_while(|(c, style)| {
+                width += font.advance(*c, style);
+                width <= max_width as f32
+            })
+            .count();
+        if fits < prompt.chars().count() {
+            prompt = prompt.slice(0, fits);
+        }
+        vec![
+            GuiDraw::Push(vec![
+                PoseOp::Scale(scale, scale),
+                PoseOp::Translate(4.0, 0.0),
+            ]),
+            hud_layout::fill(
+                -2,
+                top,
+                max_width + 4 + 4,
+                top + entry_height,
+                hud_layout::as8(o.background_opacity as f32) << 24,
+            ),
+            GuiDraw::Text {
+                text: prompt,
+                x: 0,
+                y: top + entry_height - bottom_to_text - 1,
+                color: hud_layout::white(o.opacity as f32 * 0.9 + 0.1),
+                shadow: true,
+            },
+            GuiDraw::Pop,
+        ]
     }
     /// The click action under a GUI-space cursor while chat is focused.
     pub fn click_at(
@@ -458,26 +556,34 @@ impl Chat {
     pub fn hover_at(&self, font: &crate::font::Font, height: i32, x: f64, y: f64) -> Option<Text> {
         self.style_at(font, height, x, y)?.hover.map(|h| *h)
     }
-    /// ChatComponent.getClickedComponentStyleAt.
-    fn style_at(
-        &self,
-        font: &crate::font::Font,
-        height: i32,
-        x: f64,
-        y: f64,
-    ) -> Option<crate::text::Style> {
+    /// The wrapped line under a GUI-space cursor while chat is focused, and
+    /// the cursor's x within it (the text starts at 0).
+    fn line_at(&self, height: i32, x: f64, y: f64) -> Option<(&Line, f64)> {
         let scale = self.options.scale as f32;
-        let mut x = x / f64::from(scale) - 4.0;
+        let x = x / f64::from(scale) - 4.0;
         let bottom = hud_layout::floor((height - 40) as f32 / scale);
         let from_bottom = f64::from(bottom) - y / f64::from(scale);
-        if x < 0.0 || x >= f64::from(self.max_width()) || from_bottom <= 0.0 {
+        if x >= f64::from(self.max_width()) || from_bottom <= 0.0 {
             return None;
         }
         let row = (from_bottom / f64::from(self.options.line_height())).ceil() as usize - 1;
         if row >= self.lines_per_page(true) {
             return None;
         }
-        let line = self.lines.get(self.scroll + row)?;
+        Some((self.lines.get(self.scroll + row)?, x))
+    }
+    /// ChatComponent.getClickedComponentStyleAt.
+    pub fn style_at(
+        &self,
+        font: &crate::font::Font,
+        height: i32,
+        x: f64,
+        y: f64,
+    ) -> Option<crate::text::Style> {
+        let (line, mut x) = self.line_at(height, x, y)?;
+        if x < 0.0 {
+            return None;
+        }
         let content = line.content.resolve_legacy();
         for (c, style) in content.chars() {
             x -= f64::from(font.advance(c, style));
@@ -487,6 +593,13 @@ impl Chat {
         }
         None
     }
+    /// Whether the cursor is on a line's indicator bar while chat is focused
+    /// (`DrawingFocusedGraphicsAccess.handleTag`), whose tooltip is the
+    /// message tag's text.
+    pub fn indicator_at(&self, height: i32, x: f64, y: f64) -> bool {
+        self.line_at(height, x, y)
+            .is_some_and(|(line, x)| line.indicator.is_some() && (-4.0..-2.0).contains(&x))
+    }
     /// Plain text of the newest messages (for tests and the control socket).
     pub fn recent_lines(&self, n: usize) -> Vec<String> {
         self.messages
@@ -540,6 +653,42 @@ pub struct Commands<'a> {
     pub registries: &'a Registries,
 }
 
+/// `CommandSuggestions`' constructor arguments: how a screen's suggestions
+/// parse and where they are drawn.
+#[derive(Clone, Copy, Debug, PartialEq, Eq)]
+pub struct SuggestLayout {
+    /// `commandsOnly`: the input is a command without a leading `/`.
+    pub commands_only: bool,
+    /// `onlyShowIfCursorPastError`: completions from the command's start,
+    /// not only past the `/`.
+    pub only_past_error: bool,
+    /// `suggestionLineLimit`.
+    pub line_limit: usize,
+    /// `anchorToBottom`: the list and usage over a box at the bottom, else
+    /// under one at the top (y 72).
+    pub anchor_to_bottom: bool,
+    /// `fillColor`: behind the list and the usage lines.
+    pub fill: i32,
+}
+impl SuggestLayout {
+    /// ChatScreen.init's `CommandSuggestions`.
+    pub const CHAT: Self = Self {
+        commands_only: false,
+        only_past_error: false,
+        line_limit: 10,
+        anchor_to_bottom: true,
+        fill: FILL,
+    };
+    /// AbstractCommandBlockEditScreen.init's `CommandSuggestions`.
+    pub const COMMAND_BLOCK: Self = Self {
+        commands_only: true,
+        only_past_error: true,
+        line_limit: 7,
+        anchor_to_bottom: false,
+        fill: i32::MIN,
+    };
+}
+
 /// The open chat screen: vanilla's `ChatScreen` with its `EditBox` and
 /// `CommandSuggestions` (argument colouring, usage lines, parse errors,
 /// the suggestion list, Tab completion, history).
@@ -567,6 +716,7 @@ pub struct ChatScreen {
     pub auto_suggestions: bool,
     /// `CommandSuggestions.setRestrictions`: what the Chat option allows.
     pub abilities: ChatAbilities,
+    pub layout: SuggestLayout,
 }
 /// Local completions waiting for the server's reply to request `id`.
 struct Awaiting {
@@ -637,6 +787,43 @@ impl ChatScreen {
             keep_suggestions: false,
             auto_suggestions: true,
             abilities,
+            layout: SuggestLayout::CHAT,
+        };
+        s.update_command_info(m, c);
+        s
+    }
+    /// `AbstractCommandBlockEditScreen.init`: the command box at the top,
+    /// focused, holding `command`, with suggestions from the start.
+    pub fn command_block(
+        m: &Measure,
+        c: &Commands,
+        command: &str,
+        width: i32,
+        height: i32,
+    ) -> Self {
+        let mut input = TextField::new(width / 2 - 150, 50, 300, 20);
+        input.max_length = 32500;
+        input.focused = true;
+        input.set_value(m, command);
+        let mut s = Self {
+            input,
+            width,
+            height,
+            history_buffer: String::new(),
+            history_pos: 0,
+            parse: None,
+            pending: None,
+            awaiting: None,
+            request: None,
+            suggestions: None,
+            usage: Vec::new(),
+            usage_position: 0,
+            usage_width: 0,
+            allow_suggestions: true,
+            keep_suggestions: false,
+            auto_suggestions: true,
+            abilities: ChatAbilities::new(ChatVisibility::Full),
+            layout: SuggestLayout::COMMAND_BLOCK,
         };
         s.update_command_info(m, c);
         s
@@ -655,7 +842,11 @@ impl ChatScreen {
             let value = self.input.value.clone();
             let auto = self.auto_suggestions;
             let abilities = self.abilities;
-            *self = Self::new(m, c, &value, self.history_pos, width, height, abilities);
+            *self = if self.layout == SuggestLayout::CHAT {
+                Self::new(m, c, &value, self.history_pos, width, height, abilities)
+            } else {
+                Self::command_block(m, c, &value, width, height)
+            };
             self.auto_suggestions = auto;
         }
     }
@@ -701,11 +892,18 @@ impl ChatScreen {
         self.usage.clear();
         let cursor = self.input.cursor;
         let cursor_b = byte_at(&command, cursor);
-        if command.starts_with('/') {
+        let slash = command.starts_with('/');
+        if self.layout.commands_only || slash {
+            let start = usize::from(slash);
             if self.parse.is_none() {
-                self.parse = Some(c.dispatcher.parse_at(&command, 1, c.registries));
+                self.parse = Some(c.dispatcher.parse_at(&command, start, c.registries));
             }
-            if cursor >= 1 && (self.suggestions.is_none() || !self.keep_suggestions) {
+            let from = if self.layout.only_past_error {
+                start
+            } else {
+                1
+            };
+            if cursor >= from && (self.suggestions.is_none() || !self.keep_suggestions) {
                 let parse = self.parse.as_ref().expect("parsed above");
                 let (range, list, ask) =
                     c.dispatcher
@@ -889,7 +1087,11 @@ impl ChatScreen {
             0,
             self.input.screen_x(m, 0) + self.input.inner_width() - width,
         );
-        let y = self.height - 12;
+        let y = if self.layout.anchor_to_bottom {
+            self.height - 12
+        } else {
+            72
+        };
         // sortSuggestions: those starting with the word at the cursor first.
         let partial = &value[..byte_at(&value, self.input.cursor)];
         let word = partial[last_word_index(partial)..].to_lowercase();
@@ -898,9 +1100,16 @@ impl ChatScreen {
                 s.text.starts_with(&word) || s.text.starts_with(&format!("minecraft:{word}"))
             });
         first.extend(rest);
-        let n = first.len().min(10) as i32;
+        // SuggestionsList: beside a bordered box, or over an unbordered one.
+        let n = first.len().min(self.layout.line_limit) as i32;
+        let bordered = i32::from(self.input.bordered);
+        let top = if self.layout.anchor_to_bottom {
+            y - 3 - n * 12
+        } else {
+            y - bordered
+        };
         let mut l = SuggestionList {
-            rect: [x - 1, y - 3 - n * 12, width + 1, n * 12],
+            rect: [x - (1 - bordered), top, width + 1, n * 12],
             original: value,
             list: first,
             offset: 0,
@@ -929,11 +1138,12 @@ impl ChatScreen {
     }
     fn cycle(&mut self, l: &mut SuggestionList, dir: isize) {
         self.select(l, l.current as isize + dir);
-        let max = l.list.len().saturating_sub(10);
+        let limit = self.layout.line_limit;
+        let max = l.list.len().saturating_sub(limit);
         if l.current < l.offset {
             l.offset = l.current.min(max);
-        } else if l.current > l.offset + 9 {
-            l.offset = (l.current as isize + 1 - 10).clamp(0, max as isize) as usize;
+        } else if l.current >= l.offset + limit {
+            l.offset = (l.current as isize + 1 - limit as isize).clamp(0, max as isize) as usize;
         }
     }
     /// `SuggestionsList.useSuggestion`.
@@ -961,7 +1171,57 @@ impl ChatScreen {
         ctrl: bool,
     ) -> ChatAction {
         use winit::keyboard::KeyCode as K;
-        // CommandSuggestions.keyPressed.
+        if self.suggestions_key(m, c, key, shift) {
+            return ChatAction::None;
+        }
+        match key {
+            K::Escape => return ChatAction::Close,
+            K::Enter | K::NumpadEnter => {
+                // ChatScreen.keyPressed: without `hasAllowedInput` the input
+                // stays, unsent, and the screen stays open.
+                if !self.abilities.allows(&self.input.value) {
+                    return ChatAction::None;
+                }
+                return ChatAction::Submit(self.normalized());
+            }
+            K::ArrowUp => self.move_in_history(m, c, history, -1),
+            K::ArrowDown => self.move_in_history(m, c, history, 1),
+            _ => {
+                self.field_key(m, c, key, shift, ctrl);
+            }
+        }
+        ChatAction::None
+    }
+    /// The input box's own keys (`EditBox.keyPressed`), the suggestions
+    /// following an edit: whether the box took the key.
+    pub fn field_key(
+        &mut self,
+        m: &Measure,
+        c: &Commands,
+        key: winit::keyboard::KeyCode,
+        shift: bool,
+        ctrl: bool,
+    ) -> bool {
+        match self.input.key(m, key, shift, ctrl) {
+            Some(changed) => {
+                if changed {
+                    self.edited(m, c);
+                }
+                true
+            }
+            None => false,
+        }
+    }
+    /// `CommandSuggestions.keyPressed`: the list's arrows, Tab and Escape,
+    /// and Tab to show it. True when the suggestions took the key.
+    pub fn suggestions_key(
+        &mut self,
+        m: &Measure,
+        c: &Commands,
+        key: winit::keyboard::KeyCode,
+        shift: bool,
+    ) -> bool {
+        use winit::keyboard::KeyCode as K;
         if let Some(mut l) = self.suggestions.take() {
             let handled = match key {
                 K::ArrowUp | K::ArrowDown => {
@@ -978,37 +1238,18 @@ impl ChatScreen {
                 }
                 K::Escape => {
                     self.input.suggestion = None;
-                    return ChatAction::None;
+                    return true;
                 }
                 _ => false,
             };
             self.suggestions = Some(l);
-            if handled {
-                return ChatAction::None;
-            }
+            handled
         } else if key == K::Tab {
             self.show_suggestions(m);
-            return ChatAction::None;
+            true
+        } else {
+            false
         }
-        match key {
-            K::Escape => return ChatAction::Close,
-            K::Enter | K::NumpadEnter => {
-                // ChatScreen.keyPressed: without `hasAllowedInput` the input
-                // stays, unsent, and the screen stays open.
-                if !self.abilities.allows(&self.input.value) {
-                    return ChatAction::None;
-                }
-                return ChatAction::Submit(self.normalized());
-            }
-            K::ArrowUp => self.move_in_history(m, c, history, -1),
-            K::ArrowDown => self.move_in_history(m, c, history, 1),
-            _ => {
-                if self.input.key(m, key, shift, ctrl) == Some(true) {
-                    self.edited(m, c);
-                }
-            }
-        }
-        ChatAction::None
     }
     /// `ChatScreen.moveInHistory`.
     fn move_in_history(&mut self, m: &Measure, c: &Commands, history: &[String], dir: isize) {
@@ -1062,7 +1303,7 @@ impl ChatScreen {
         if !l.contains(mouse.0, mouse.1) {
             return false;
         }
-        let max = l.list.len().saturating_sub(10) as i32;
+        let max = l.list.len().saturating_sub(self.layout.line_limit) as i32;
         l.offset = ((l.offset as f64 - amount.clamp(-1.0, 1.0)) as i32).clamp(0, max) as usize;
         true
     }
@@ -1133,7 +1374,9 @@ impl ChatScreen {
     ) -> Vec<Draw> {
         let (w, h) = (self.width, self.height);
         let mut out = Vec::new();
-        d::fill(&mut out, 2, h - 14, w - 2, h - 2, background);
+        if self.layout.anchor_to_bottom {
+            d::fill(&mut out, 2, h - 14, w - 2, h - 2, background);
+        }
         let format = |s: &str, o: usize| self.format(s, o);
         self.input.draw(&mut out, m, blink_ms, Some(&format));
         if let Some(mut l) = self.suggestions.take() {
@@ -1141,14 +1384,18 @@ impl ChatScreen {
             self.suggestions = Some(l);
         } else {
             for (i, line) in self.usage.iter().enumerate() {
-                let y = h - 27 - 12 * i as i32;
+                let y = if self.layout.anchor_to_bottom {
+                    h - 27 - 12 * i as i32
+                } else {
+                    72 + 12 * i as i32
+                };
                 d::fill(
                     &mut out,
                     self.usage_position - 1,
                     y,
                     self.usage_position + self.usage_width + 1,
                     y + 12,
-                    FILL,
+                    self.layout.fill,
                 );
                 d::text(&mut out, line.clone(), self.usage_position, y + 2, -1, true);
             }
@@ -1162,7 +1409,7 @@ impl ChatScreen {
         l: &mut SuggestionList,
         mouse: (i32, i32),
     ) {
-        let limit = l.list.len().min(10);
+        let limit = l.list.len().min(self.layout.line_limit);
         let [rx, ry, rw, rh] = l.rect;
         let has_prev = l.offset > 0;
         let has_next = l.list.len() > l.offset + limit;
@@ -1171,8 +1418,8 @@ impl ChatScreen {
             l.last_mouse = mouse;
         }
         if has_prev || has_next {
-            d::fill(out, rx, ry - 1, rx + rw, ry, FILL);
-            d::fill(out, rx, ry + rh, rx + rw, ry + rh + 1, FILL);
+            d::fill(out, rx, ry - 1, rx + rw, ry, self.layout.fill);
+            d::fill(out, rx, ry + rh, rx + rw, ry + rh + 1, self.layout.fill);
             if has_prev {
                 for x in (0..rw).step_by(2) {
                     d::fill(out, rx + x, ry - 1, rx + x + 1, ry, -1);
@@ -1187,7 +1434,7 @@ impl ChatScreen {
         let mut hovered = false;
         for i in 0..limit {
             let y = ry + 12 * i as i32;
-            d::fill(out, rx, y, rx + rw, y + 12, FILL);
+            d::fill(out, rx, y, rx + rw, y + 12, self.layout.fill);
             if mouse.0 > rx && mouse.0 < rx + rw && mouse.1 > y && mouse.1 < y + 12 {
                 if moved {
                     self.select(l, (i + l.offset) as isize);

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

@@ -2,9 +2,12 @@
 //! threads can mesh and light immutable snapshots while the game thread edits
 //! (copy-on-write through `Arc::make_mut`).
 use horizon_core::paletted::{PalettedContainer, Strategy};
+use horizon_world::nbt::{Compound, Tag};
 use horizon_world::registry::BlockStateId;
 use std::sync::{Arc, OnceLock};
 
+pub mod block_entity;
+
 pub const MIN_Y: i32 = -64;
 pub const HEIGHT: i32 = 384;
 pub const SECTIONS: usize = (HEIGHT / 16) as usize;
@@ -148,19 +151,22 @@ pub struct Chunk {
     /// Newly generated (not loaded from a save): eligible for generation-time spawns.
     pub fresh: bool,
     /// Block entities read from a save, moved into the world on arrival.
-    pub block_entities: Vec<((i32, i32, i32), crate::containers::BlockEntity)>,
+    pub block_entities: Vec<((i32, i32, i32), block_entity::BlockEntity)>,
     /// `CustomName` of the container block entities (shown as the screen title).
     pub block_names: Vec<((i32, i32, i32), String)>,
     /// Generation postprocessing marks (ProtoChunk.postProcessing) as world
     /// positions, applied once by LevelChunk.postProcessGeneration.
     pub postprocess: Vec<[i32; 3]>,
     /// Saved data Horizon keeps but does not simulate (save.rs).
-    pub saved: Option<Arc<crate::save::ChunkExtras>>,
+    pub saved: Option<Arc<ChunkExtras>>,
     /// Entities read from a save (vanilla entity NBT), spawned on arrival.
     pub entities: Vec<horizon_world::nbt::Tag>,
     /// Structure starts reaching into this chunk (`structures.References`):
     /// structure id and the start's chunk.
     pub structure_refs: Vec<(Arc<str>, (i32, i32))>,
+    /// The starts generation made in this chunk (`structures.starts`), saved
+    /// with the state their placement has reached by then.
+    pub structure_starts: Vec<Arc<horizon_world::worldgen::structure::start::StructureStart>>,
 }
 impl Chunk {
     pub fn empty(x: i32, z: i32) -> Self {
@@ -178,6 +184,7 @@ impl Chunk {
             block_entities: Vec::new(),
             block_names: Vec::new(),
             structure_refs: Vec::new(),
+            structure_starts: Vec::new(),
             postprocess: Vec::new(),
             saved: None,
             entities: Vec::new(),
@@ -305,6 +312,76 @@ impl Chunk {
     }
 }
 
+/// A proto chunk saved before it became final. Decoration writes into a
+/// chunk's neighbours, and decorated chunks wait for theirs, so the chunks
+/// past the finished ones hold writes that generating them again would lose
+/// (whole structure pieces, trees, ores). Vanilla saves its proto chunks too.
+pub struct SavedProto {
+    /// Blocks, scheduled ticks (in `saved`) and post-processing marks.
+    pub column: Chunk,
+    /// Decorated itself (`features`), not only written to by its neighbours
+    /// (`terrain`).
+    pub decorated: bool,
+    /// Block entity data in placement order, with `x`, `y` and `z`.
+    pub block_entities: Vec<Tag>,
+    /// Entities placed by structures, with absolute `Pos`.
+    pub entities: Vec<Tag>,
+}
+
+/// A container's loot table and what Horizon rolled from it. Vanilla keeps
+/// `LootTable` and `LootTableSeed` until the container is first opened;
+/// Horizon rolls when it generates or loads the chunk, and saves the table
+/// again while the container still holds exactly the rolled items.
+#[derive(Clone, Debug, PartialEq)]
+pub struct RolledLoot {
+    pub pos: (i32, i32, i32),
+    pub table: String,
+    /// The saved `LootTableSeed`, written back unless 0 (trySaveLootTable).
+    pub seed: Option<i64>,
+    /// The rolled `Items`.
+    pub items: Tag,
+}
+impl RolledLoot {
+    /// Puts the loot table back in place of `Items` while they are still the
+    /// roll; false once the container holds anything else.
+    pub fn restore(&self, map: &mut Compound) -> bool {
+        if map.get(&"Items".into()) != Some(&self.items) {
+            return false;
+        }
+        map.remove(&"Items".into());
+        map.insert("LootTable".into(), Tag::String(self.table.as_str().into()));
+        if let Some(seed) = self.seed.filter(|s| *s != 0) {
+            map.insert("LootTableSeed".into(), Tag::Long(seed));
+        }
+        true
+    }
+}
+
+/// Save data loaded with a chunk that Horizon keeps but does not simulate.
+#[derive(Clone, Debug, Default)]
+pub struct ChunkExtras {
+    /// Chunk root keys written back as loaded (structures, PostProcessing,
+    /// InhabitedTime, blending data, ...).
+    pub root: Compound,
+    /// Block entities Horizon does not model.
+    pub block_entities: Vec<Tag>,
+    /// The NBT of the modelled block entities as loaded, to restore the fields and
+    /// detail Horizon does not model when it saves them (`block_entity_nbt::overlay`).
+    pub block_entity_sources: Vec<((i32, i32, i32), Tag)>,
+    /// Every saved block entity's position in the order of the save's list,
+    /// the order `SerializableChunkData` puts them in the chunk's maps.
+    pub block_entity_order: Vec<(i32, i32, i32)>,
+    /// Scheduled ticks (`block_ticks`/`fluid_ticks`): delays relative to the
+    /// save time. Registered with the level's tick scheduler on arrival and
+    /// replaced with the scheduler's pending ticks when saving.
+    pub block_ticks: Vec<horizon_core::ticks::SavedTick>,
+    pub fluid_ticks: Vec<horizon_core::ticks::SavedTick>,
+    /// Game time written as `LastUpdate`.
+    pub last_update: i64,
+    /// Containers still holding their loot table's roll.
+    pub rolled_loot: Vec<RolledLoot>,
+}
+
 #[cfg(test)]
 mod tests {
     use super::*;