ci: wgpu sanity check on macOS

Lightweight workflow that compiles IfcViewerWgpu (the static lib) on
macOS arm64 + runs the wgpu state tests. Skips IfcViewerWgpuMinimal
because createSurface has no Metal path yet (task #32); the platform
surface blocks in WgpuViewportWindow.cpp are wrapped in
#if defined(Q_OS_LINUX) so the lib itself compiles cleanly on macOS.

Goal: catch portability regressions in the wgpu source on Apple
Silicon without paying for build_osx.yml's full IfcGeom + OCCT +
Python wheel pipeline. ~5 min vs hours.

Triggers on push/PR that touches src/ifcviewer-wgpu, the shared
headers it depends on, the top-level CMake, or this workflow itself.
Also workflow_dispatch for manual runs.

Hoists the Catch2 fetch in cmake/CMakeLists.txt out of the
BUILD_BONSAIVIEWER gate so the standalone wgpu config
(BUILD_BONSAIVIEWER=OFF + BUILD_BONSAIVIEWER_WGPU=ON +
BUILD_BONSAIVIEWER_TESTS=ON) can build tests without dragging the
whole bonsai/IfcGeom tree in. Default remains OFF, so default builds
stay offline-capable.

Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>

.github/workflows/ci-wgpu-mac.yml

@@ -0,0 +1,101 @@
+name: wgpu sanity (macOS)
+
+# Lightweight compile-only check for the wgpu backend on macOS. Skips the
+# IfcViewerWgpuMinimal executable (its surface creation has no Metal path
+# yet — see task #32) and just confirms IfcViewerWgpu links and the pure-
+# CPU state tests pass.
+#
+# Goal: catch portability regressions in the wgpu source on Apple Silicon
+# / Intel Mac without needing the full IfcGeom + OCCT + Python toolchain
+# that build_osx.yml carries. Runs in ~5 minutes.
+
+on:
+  push:
+    branches:
+      - ifcviewer-wgpu
+      - main
+      - v0.8.0
+    paths:
+      - 'src/ifcviewer-wgpu/**'
+      - 'src/ifcviewer/SidecarCache.*'
+      - 'src/ifcviewer/InstancedGeometry.h'
+      - 'src/ifcviewer/VertexQuantization.h'
+      - 'cmake/CMakeLists.txt'
+      - '.github/workflows/ci-wgpu-mac.yml'
+  pull_request:
+    paths:
+      - 'src/ifcviewer-wgpu/**'
+      - 'src/ifcviewer/SidecarCache.*'
+      - 'src/ifcviewer/InstancedGeometry.h'
+      - 'src/ifcviewer/VertexQuantization.h'
+      - 'cmake/CMakeLists.txt'
+      - '.github/workflows/ci-wgpu-mac.yml'
+  workflow_dispatch:
+
+jobs:
+  build_wgpu_mac:
+    runs-on: ${{ matrix.runner }}
+    strategy:
+      fail-fast: false
+      matrix:
+        include:
+          - arch: arm64
+            runner: macos-14
+
+    steps:
+      - name: Checkout
+        uses: actions/checkout@v4
+        with:
+          submodules: false
+
+      - name: Install dependencies via Homebrew
+        run: |
+          brew update
+          # qt installs Qt6 currently; eigen is header-only.
+          brew install qt eigen
+          # patchelf isn't on mac — wgpu-native's SONAME workaround is
+          # Linux-only and CMake guards on UNIX AND NOT APPLE so this is fine.
+
+      - name: ccache
+        uses: hendrikmuhs/ccache-action@v1.2.22
+        with:
+          key: mac-wgpu-${{ matrix.arch }}
+
+      - name: Configure (standalone wgpu, tests on)
+        shell: bash
+        run: |
+          QT_PREFIX="$(brew --prefix qt)"
+          cmake -B build \
+            -S cmake \
+            -G Ninja \
+            -DCMAKE_BUILD_TYPE=Release \
+            -DBUILD_BONSAIVIEWER=OFF \
+            -DBUILD_BONSAIVIEWER_WGPU=ON \
+            -DBUILD_BONSAIVIEWER_TESTS=ON \
+            -DCMAKE_PREFIX_PATH="${QT_PREFIX}" \
+            -DQT_DIR="${QT_PREFIX}" \
+            -DCMAKE_C_COMPILER_LAUNCHER=ccache \
+            -DCMAKE_CXX_COMPILER_LAUNCHER=ccache
+
+      - name: Build IfcViewerWgpu + state tests
+        # Skip IfcViewerWgpuMinimal: its createSurface has no Metal path
+        # yet (task #32). Static lib compiles cleanly because the X11 /
+        # Wayland surface blocks are wrapped in #if defined(Q_OS_LINUX).
+        run: |
+          cmake --build build \
+            --target IfcViewerWgpu test_wgpu_selection test_wgpu_visibility \
+            -- -j
+
+      - name: Run state tests
+        working-directory: build
+        run: ctest --output-on-failure -R "wgpu"
+
+      - name: Upload CMake configure log on failure
+        if: failure()
+        uses: actions/upload-artifact@v4
+        with:
+          name: cmake-log-${{ matrix.arch }}
+          path: |
+            build/CMakeCache.txt
+            build/CMakeFiles/CMakeConfigureLog.yaml
+          retention-days: 14

cmake/CMakeLists.txt

@@ -681,24 +681,25 @@ if(BUILD_IFCGEOM)
 
     install(TARGETS ${IFCGEOM_SCHEMA_LIBRARIES} ${kernel_libraries} IfcGeom)
 endif(BUILD_IFCGEOM)
-if(BUILD_BONSAIVIEWER)
-    if(BUILD_BONSAIVIEWER_TESTS)
-        # Catch2 v3 — fetched on demand. Test option is OFF by default so the
-        # default build remains offline-capable.
-        include(FetchContent)
-        FetchContent_Declare(
-            Catch2
-            GIT_REPOSITORY https://github.com/catchorg/Catch2.git
-            GIT_TAG        v3.5.4
-            GIT_SHALLOW    TRUE
-        )
-        FetchContent_MakeAvailable(Catch2)
-        list(APPEND CMAKE_MODULE_PATH ${catch2_SOURCE_DIR}/extras)
-        include(CTest)
-        include(Catch)
-        enable_testing()
-    endif()
+# Catch2 fetch hoisted out of BUILD_BONSAIVIEWER so the standalone wgpu
+# build can also enable BUILD_BONSAIVIEWER_TESTS. Test option is OFF by
+# default so the default build remains offline-capable.
+if(BUILD_BONSAIVIEWER_TESTS)
+    include(FetchContent)
+    FetchContent_Declare(
+        Catch2
+        GIT_REPOSITORY https://github.com/catchorg/Catch2.git
+        GIT_TAG        v3.5.4
+        GIT_SHALLOW    TRUE
+    )
+    FetchContent_MakeAvailable(Catch2)
+    list(APPEND CMAKE_MODULE_PATH ${catch2_SOURCE_DIR}/extras)
+    include(CTest)
+    include(Catch)
+    enable_testing()
+endif()
 
+if(BUILD_BONSAIVIEWER)
     # Wgpu subprojects added first because IfcViewer's SceneLoader now
     # links against IfcViewerWgpu; the target must exist when IfcViewer's
     # CMakeLists runs.