feat(compositor): port the compositor to macOS (Metal + VideoToolbox)

.github/workflows/ci.yml

@@ -97,6 +97,114 @@ jobs:
       - uses: ./.github/actions/setup
       - run: npx vite build
 
+  # PR #189 — port macOS du compositor (Metal + VideoToolbox).
+  #
+  # Compile check on a `macos-14` runner (Apple Silicon). Verifies that the
+  # scaffold + engine-layer code added by #189 actually compiles for
+  # `aarch64-apple-darwin` — bindgen + cc on macOS produce the ffmpeg FFI
+  # bindings + the VideoToolbox context that the Rust crate statically
+  # references, and the `metal`/`objc`/`block`/`core-foundation` crates need
+  # their macOS system frameworks (Metal/CoreVideo/CoreMedia) linked.
+  #
+  # ffmpeg via Homebrew: this job installs `ffmpeg` from homebrew-core on the
+  # runner to satisfy bindgen + the cargo:rustc-link-lib lines for avformat/
+  # avcodec/avutil/swscale/swresample. NB: homebrew's `ffmpeg` is GPL-3.0 (it
+  # bundles x264/x265/svt-av1 etc.) — that is fine for a CI compile-check, but
+  # the dev/runtime story is different: `scripts/fetch-ffmpeg.mjs` documents
+  # that BtbN publishes no macOS build, so a pinned LGPL macOS dylib has to
+  # land separately before we can ship. The vendored `electron/native/bin/
+  # darwin-*/` directory is the runtime pin and is empty today.
+  #
+  # Why this job runs at all today: every commit on #189 that touches
+  # compositor_macos.rs / pipeline_macos.rs / mac_frames.rs / shaders.metal /
+  # d3d_macos.rs / text_macos.rs is unverifiable from Windows (cross-compile
+  # requires the macOS SDK + headers, which we don't have). This job is the
+  # only signal that the macOS-side Rust still type-checks.
+  #
+  # `cargo test`, NOT just `cargo check` — and that difference is the whole point.
+  # Three of the bugs that kept the first macOS run from rendering anything are
+  # invisible to a type-check and are each pinned by a test now:
+  #   * `shaders.metal` is compiled AT RUNTIME by `new_library_with_source`, so a
+  #     whole file of invalid MSL (HLSL's global `cbuffer`/`Texture2D` have no MSL
+  #     equivalent) type-checks perfectly — `every_shader_entry_point_compiles`
+  #     catches it. macos-14 runners have a real Metal device, so it runs for real.
+  #   * `AVERROR(EAGAIN)` is -11 on Windows/Linux and -35 on macOS. A hardcoded -11
+  #     compiles anywhere and silently decodes zero frames —
+  #     `averror_constants_match_the_ffmpeg_macros` confronts it with shim.c.
+  #   * pipeline-state creation rejects shader/attachment mismatches only at
+  #     `newRenderPipelineState` time — `the_compositor_builds_on_the_system_device`.
+  rust-macos-compositor-check:
+    name: Rust test (macOS compositor)
+    runs-on: macos-14
+    steps:
+      - uses: actions/checkout@v4
+      - name: Install Rust toolchain
+        run: |
+          curl --proto '=https' --tlsv1.2 -sSf https://sh.rustup.rs | sh -s -- -y --default-toolchain stable --target aarch64-apple-darwin
+          echo "$HOME/.cargo/bin" >> "$GITHUB_PATH"
+      - name: Install ffmpeg (homebrew-core) and verify headers/libs
+        run: |
+          brew update
+          brew install ffmpeg
+          ls /opt/homebrew/opt/ffmpeg/include | head -5
+          ls /opt/homebrew/opt/ffmpeg/lib | head -5
+          /opt/homebrew/opt/ffmpeg/bin/ffmpeg -hide_banner -version | head -1
+      # MAC_FFMPEG_DIR only reaches build.rs because it now takes precedence over
+      # FFMPEG_DIR on macOS. crates/.cargo/config.toml sets FFMPEG_DIR in a GLOBAL
+      # [env] block (cargo has no [target.<cfg>.env] — the macOS section in that file
+      # is inert and cargo warns "unused key"), so before that change this job pointed
+      # bindgen at the win64 tree and could never have gone green.
+      - name: cargo test (compositor, aarch64-apple-darwin)
+        env:
+          MAC_FFMPEG_DIR: /opt/homebrew/opt/ffmpeg
+        run: |
+          cd crates
+          cargo test -p openscreen-compositor --lib --tests
+      - name: cargo build (napi addon)
+        env:
+          MAC_FFMPEG_DIR: /opt/homebrew/opt/ffmpeg
+        run: |
+          cd crates
+          cargo build -p compositor-view-napi --release
+
+  # The Windows half of the compositor had NO type-check on any pull request.
+  # `ci.yml`'s only Rust job is the macOS one above; `compositor_windows.rs` — the
+  # 3654-line D3D11 engine that every Windows user actually runs — is compiled
+  # exclusively by `build.yml`'s `build-windows` step (`npm run build:win`), and
+  # build.yml triggers only on `push: tags: v*` or `workflow_dispatch`. A typo in
+  # that file therefore surfaced when someone cut a release, not when they pushed it.
+  #
+  # That gap is what makes any cross-platform refactor of the compositor a blind
+  # edit, so it gets closed before the refactor rather than after.
+  #
+  # `cargo check`, not `build`: the point is "does the Windows engine still compile",
+  # and check is roughly half the wall-time of a full build on a windows runner.
+  rust-windows-compositor-check:
+    name: Rust check (Windows compositor)
+    runs-on: windows-latest
+    steps:
+      - uses: actions/checkout@v4
+      - uses: actions/setup-node@v4
+        with:
+          node-version-file: .nvmrc
+      # bindgen needs libclang. `crates/.cargo/config.toml` pins LIBCLANG_PATH to
+      # C:\Program Files\LLVM\bin, which is where the windows-latest image already
+      # has LLVM — so the pin resolves with no extra install.
+      - name: Check LLVM is where the cargo config expects it
+        shell: bash
+        run: ls "/c/Program Files/LLVM/bin/libclang.dll"
+      # Vendors the pinned BtbN LGPL-shared build into
+      # crates/thirdparty/ffmpeg-n8.1.2-win64-lgpl-shared — the exact directory
+      # FFMPEG_DIR points at (crates/.cargo/config.toml). build.rs reads the headers
+      # from there and links the import libs.
+      - name: Vendor the pinned ffmpeg
+        run: npm run fetch:ffmpeg
+      - name: cargo check (compositor + napi addon)
+        shell: bash
+        run: |
+          cd crates
+          cargo check -p openscreen-compositor -p compositor-view-napi --all-targets
+
   semantic-pr:
     name: Validate PR title (semantic)
     runs-on: ubuntu-latest

crates/.cargo/config.toml

@@ -11,3 +11,10 @@
 [env]
 FFMPEG_DIR = { value = "thirdparty/ffmpeg-n8.1.2-win64-lgpl-shared", relative = true }
 LIBCLANG_PATH = "C:\\Program Files\\LLVM\\bin"
+
+# macOS : BtbN ne publie pas de build macOS (cf. scripts/fetch-ffmpeg.mjs), donc on
+# laisse `crates/compositor/build.rs` chercher MAC_FFMPEG_DIR (env var explicite posée
+# par la CI macOS ou par le dev local) ou un répertoire attendu sous `thirdparty/`.
+# LIBCLANG_PATH est inutile sur macOS (clang est dans CommandLineTools), on ne le
+# pose donc pas.
+[target.'cfg(target_os = "macos")'.env]

crates/.gitignore

@@ -4,8 +4,10 @@
 # dépendance téléchargée : build ffmpeg LGPL-shared BtbN (~160 Mo, voir README)
 /thirdparty
 
-# sorties générées (vidéos C*.mp4, PNG, GIF, dumps)
-/out
+# sorties générées (vidéos C*.mp4, PNG, PPM, GIF, dumps). Le glob couvre les `--out`
+# nommés par backend (out-hw/, out-cpu/) : un PPM de preuve pèse 6 Mo et il en sort un
+# par cfg et par backend.
+/out*
 *.raw
 *.nv12