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

.github/workflows/ci.yml

@@ -99,6 +99,52 @@ 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.
+  rust-macos-compositor-check:
+    name: Rust check (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
+      - name: cargo check (compositor + napi addon, aarch64-apple-darwin)
+        env:
+          MAC_FFMPEG_DIR: /opt/homebrew/opt/ffmpeg
+        run: |
+          cd crates
+          cargo check --target aarch64-apple-darwin -p openscreen-compositor -p compositor-view-napi
+
   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
 

crates/compositor-view-napi/Cargo.toml

@@ -2,7 +2,7 @@
 name = "compositor-view-napi"
 version.workspace = true
 edition.workspace = true
-description = "Addon napi-rs : expose openscreen_compositor::live::LiveView (fenêtre D3D enfant) à Electron. C'est CE crate qui produit compositor_view.node, le binaire packagé dans l'app."
+description = "Addon napi-rs : expose openscreen_compositor::live::LiveView (vue offscreen multiplateforme) à Electron. C'est CE crate qui produit compositor_view.node, le binaire packagé dans l'app."
 
 [lib]
 crate-type = ["cdylib"]
@@ -14,9 +14,13 @@ napi-derive = "2"
 openscreen-compositor.workspace = true
 anyhow.workspace = true
 
-[dependencies.windows]
+# Le crate n'utilise pas directement l'API Windows — c'est transitif via le
+# moteur de composition (qui expose la même surface publique cross-platform via
+# la ré-export cfg dans `openscreen_compositor::lib`). On garde la dépendance
+# cfg-conditionnelle pour que le crate compile sur macOS.
+[target.'cfg(windows)'.dependencies.windows]
 version = "0.58"
 features = ["Win32_Foundation"]
 
 [build-dependencies]
-napi-build = "2"
+napi-build = "2"