piglit on Android against MobileGL
Run piglit desktop-GL tests on a connected Android device with MobileGL as the OpenGL implementation, for both backends:
DirectGLES— MobileGL over the system GLES driver (or ANGLE with--use-angle)DirectVulkan— MobileGL over the system Vulkan driver
No APK and no on-device python: piglit test binaries run as the adb shell user
from /data/local/tmp, create contexts through waffle's surfaceless_egl
platform, and waffle is pointed at libMobileGL.so (which exports the full
egl*/gl* API under real names).
How it fits together
piglit test binary (aarch64, bionic)
└─ waffle surfaceless_egl (patched)
├─ WAFFLE_EGL_LIBRARY=libMobileGL.so → dlopen MobileGL as the EGL impl
├─ WAFFLE_GL_LIBRARY=libMobileGL.so → waffle_dl_sym resolves gl* here
├─ WAFFLE_FORCE_GL_CONTEXT_VERSION=33core
│ upgrades low compat context requests to GL 3.3 core (never
│ downgrades) so piglit's supports_gl_compat_version=10 tests run
└─ WAFFLE_ANDROID_WINDOW=imagereader (DirectVulkan only)
windows are AImageReader ANativeWindows instead of EGL pbuffers,
because Android ICDs lack VK_EXT_headless_surface which the
MobileGL pbuffer path needs
└─ libMobileGL.so
├─ DirectGLES: dlopens the real system libEGL.so internally
└─ DirectVulkan: links libvulkan.so
Key rule: never name MobileGL libEGL.so anywhere on LD_LIBRARY_PATH —
the DirectGLES backend loads the system driver with a bare-soname
dlopen("libEGL.so") and would recursively pick itself up.
One-time setup (host: macOS/Linux with the Android NDK)
WORK=path/to/workdir && cd $WORK
git clone --depth 1 https://gitlab.freedesktop.org/mesa/piglit.git
git clone --depth 1 https://gitlab.freedesktop.org/mesa/waffle.git
git -C waffle apply $MOBILEGL/tools/piglit-android/patches/waffle-mobilegl-android.patch
git -C piglit apply $MOBILEGL/tools/piglit-android/patches/piglit-mobilegl-android.patch
python3 -m venv venv && ./venv/bin/pip install mako numpy packaging
The piglit patch matters beyond build fixes: upstream's
piglit_dispatch_default_init runs while the waffle framework is still being
constructed (gl_fw is NULL), so the waffle resolvers were never installed and
GL functions bound through the system libEGL's eglGetProcAddress — every
test silently ran on the raw GLES driver instead of MobileGL.
Build MobileGL for Android:
cmake -S $MOBILEGL -B $MOBILEGL/build-android-arm64 -G Ninja \
-DCMAKE_TOOLCHAIN_FILE=$NDK/build/cmake/android.toolchain.cmake \
-DANDROID_ABI=arm64-v8a -DANDROID_PLATFORM=android-26 \
-DCMAKE_BUILD_TYPE=RelWithDebInfo
cmake --build $MOBILEGL/build-android-arm64 --target MobileGL -j
$NDK/toolchains/llvm/prebuilt/*/bin/llvm-strip --strip-unneeded \
-o $WORK/libMobileGL-stripped.so $MOBILEGL/build-android-arm64/libMobileGL.so
Cross-build waffle (meson; a cross file and a stub egl.pc pointing at
MobileGL's bundled EGL 1.5 headers are needed — see cross-example/):
cd $WORK/waffle
meson setup build-android --cross-file $WORK/cross/android-arm64.ini \
-Dbuildtype=release -Dsurfaceless_egl=enabled \
-Dglx=disabled -Dx11_egl=disabled -Dgbm=disabled -Dwayland=disabled \
-Dbuild-tests=false -Dbuild-examples=false -Dprefix=$WORK/prefix
ninja -C build-android && meson install -C build-android
Cross-build piglit (needs PKG_CONFIG_LIBDIR with the installed waffle-1.pc
plus the stub egl.pc):
cd $WORK/piglit && export PKG_CONFIG_LIBDIR=$WORK/prefix/lib/pkgconfig:$WORK/cross/pkgconfig
cmake -S . -B build-android -G Ninja \
-DCMAKE_TOOLCHAIN_FILE=$NDK/build/cmake/android.toolchain.cmake \
-DANDROID_ABI=arm64-v8a -DANDROID_PLATFORM=android-26 \
-DCMAKE_BUILD_TYPE=Release \
-DPIGLIT_USE_WAFFLE=ON -DPIGLIT_BUILD_GL_TESTS=ON \
-DPIGLIT_BUILD_GLES1_TESTS=OFF -DPIGLIT_BUILD_GLES2_TESTS=OFF \
-DPIGLIT_BUILD_GLES3_TESTS=OFF -DPIGLIT_BUILD_EGL_TESTS=OFF \
-DPIGLIT_BUILD_GLX_TESTS=OFF -DPIGLIT_BUILD_WGL_TESTS=OFF \
-DPIGLIT_BUILD_CL_TESTS=OFF -DPIGLIT_BUILD_VK_TESTS=OFF \
-DPIGLIT_BUILD_DMA_BUF_TESTS=OFF -DPIGLIT_USE_GBM=OFF \
-DPIGLIT_USE_WAYLAND=OFF -DPIGLIT_USE_X11=OFF \
-DPYTHON_EXECUTABLE=$WORK/venv/bin/python \
-DOPENGL_INCLUDE_DIR=$MOBILEGL/include \
-DOPENGL_gl_LIBRARY=$SYSROOT/usr/lib/aarch64-linux-android/26/libEGL.so \
-DGLEXT_INCLUDE_DIR=$MOBILEGL/include
ninja -C build-android
Selecting tests
Enumerate on the host with piglit's own profiles (no device needed):
cd $WORK/piglit
for prof in opengl shader glslparser; do
PIGLIT_BUILD_DIR=$PWD/build-android ./venv/bin/python ./piglit print-cmd \
-t "spec@!opengl 3[.]" -t "spec@glsl-3[.]30" $prof
done > /tmp/gl33.list
Group names use @ separators (spec@!opengl 3.3@minmax). The version groups
(spec@!opengl 1.x…3.3), GLSL groups (spec@glsl-1.10…3.30) plus the ARB
extension groups folded into GL 3.1–3.3 core give a comprehensive "GL 3.3
core" suite (~15k tests).
Running
python3 $MOBILEGL/tools/piglit-android/run_piglit_android.py \
--piglit-root $WORK/piglit --list /tmp/gl33.list \
--backend DirectGLES \
--mobilegl-lib $WORK/libMobileGL-stripped.so \
--waffle-lib $WORK/waffle/build-android/src/waffle/libwaffle-1.so \
--out results-gles
# then the same with --backend DirectVulkan --out results-vk
The runner pushes binaries/libs/data (incremental; --repush forces), executes
tests serially in chunked on-device shell scripts under timeout, parses the
PIGLIT: {...} result lines, and writes results.json + summary.txt +
raw.log. Exit-code semantics: parsed result wins; nonzero exit without a
result line = crash; toybox timeout exits = timeout.
Quick sanity check for the whole stack (waffle build also produces wflinfo):
adb shell 'cd /data/local/tmp/piglit-mgl && env LD_LIBRARY_PATH=$PWD/lib \
WAFFLE_EGL_LIBRARY=libMobileGL.so WAFFLE_GL_LIBRARY=libMobileGL.so \
MOBILEGL_BACKEND_TYPE=DirectVulkan WAFFLE_ANDROID_WINDOW=imagereader \
./wflinfo --platform surfaceless_egl --api gl --version 3.3 --profile core'
Expect OpenGL version string: 3.3.0 MobileGL …, Direct (Vulkan) Backend.
Known caveats
- MSAA winsys configs never match (MobileGL exposes two RGBA8888 configs, samples=0); MSAA FBO tests are unaffected.
- Tests that genuinely require compatibility-profile features will fail on the forced 3.3 core context; that is honest for a core-only implementation.
eglTerminateat test exit now tears MobileGL down deterministically (see the EGL-lifecycle refactor); a device-sidemobilegl.logis written per run directory for debugging.