MobileGL/tools/trace_replay

MobileGL trace replay

This directory builds a Linux command line replay runner for apitrace files. It is an integration testing infrastructure of MobileGL.

The bundled fixtures cover:

• OpenRA: sourced from GL4ES' apitrace corpus.
• minecraft-1.21.4-startup: captured from Minecraft 1.21.4's startup screen.
• minecraft-1.21.4-main-menu: captured from Minecraft 1.21.4's main menu.
• minecraft-1.21.11-main-menu: captured from Minecraft 1.21.11's main menu on a Pixel 8 Pro through FCL MobileGL.
• minecraft-1.17-main-menu-854: captured from Minecraft 1.17's 854x480 main menu through FCL MobileGL capture.
• minecraft-1.21.4-in-world: captured from Minecraft 1.21.4 after entering a singleplayer world.
• minecraft-1.21.4-rd12-odinlite-in-world: captured on an Android device (FCL MobileGL Magma capture, 854x480) from vanilla Minecraft 1.21.4 at render distance 12, drifting down a river valley in a boat. Unlike the other in-world fixtures this one is a 251-frame window (gltrim -f 1094-1343) rather than a single frame, so it doubles as the campaign's benchmark scene: benchmark mode replays the whole window and the tail frames measure steady-state in-world frame time. The golden is still the final frame, so it works as an ordinary correctness case too.
• minecraft-1.21.4-fabric-sodium-in-world: captured from Minecraft 1.21.4 Fabric with Sodium after entering a singleplayer world with Fancy graphics.
• improved-transparency-minecraft-26.3: captured from the Minecraft 26.3 improved-transparency scene.
• minecraft-1.21.4-fabric-common-mods-in-world: captured from Minecraft 1.21.4 Fabric with Sodium, Iris, REI, Xaero's Minimap, Xaero's World Map, JourneyMap, and Modern UI, with shader packs disabled.
• minecraft-1.21.4-fabric-common-mods-inventory: captured from Minecraft 1.21.4 Fabric with Sodium, Iris, REI, Xaero's Minimap, Xaero's World Map, JourneyMap, and Modern UI with the creative inventory and REI item list open.
• minecraft-1.21.4-fabric-rei-inventory: captured from Minecraft 1.21.4 Fabric with Sodium, Iris, and REI, with shader packs disabled and the creative inventory and REI item list open.
• minecraft-1.21.4-fabric-xaero-minimap-in-world: captured from Minecraft 1.21.4 Fabric with Sodium, Iris, and Xaero's Minimap after entering a singleplayer world with shader packs disabled.
• minecraft-1.21.4-fabric-xaero-world-map-in-world: captured from Minecraft 1.21.4 Fabric with Sodium, Iris, and Xaero's World Map, with shader packs disabled and the world map screen open.
• minecraft-1.21.4-fabric-journeymap-in-world: captured from Minecraft 1.21.4 Fabric with Sodium, Iris, and JourneyMap after entering a singleplayer world with shader packs disabled.
• minecraft-1.21.4-fabric-modernui-inventory: captured from Minecraft 1.21.4 Fabric with Sodium, Iris, and Modern UI, with shader packs disabled and the creative inventory open.
• minecraft-1.21.4-fabric-rei-inventory-normal-world: captured from Minecraft 1.21.4 Fabric with Sodium, Iris, and REI in a normal singleplayer world, with shader packs disabled and the creative inventory and REI item list open.
• minecraft-1.21.4-fabric-xaero-minimap-in-world-normal-world: captured from Minecraft 1.21.4 Fabric with Sodium, Iris, and Xaero's Minimap after entering a normal singleplayer world with shader packs disabled.
• minecraft-1.21.4-fabric-xaero-world-map-in-world-normal-world: captured from Minecraft 1.21.4 Fabric with Sodium, Iris, and Xaero's World Map in a normal singleplayer world, with shader packs disabled and the world map screen open.
• minecraft-1.21.4-fabric-journeymap-in-world-normal-world: captured from Minecraft 1.21.4 Fabric with Sodium, Iris, and JourneyMap after entering a normal singleplayer world with shader packs disabled.
• minecraft-1.21.4-fabric-modernui-inventory-normal-world: captured from Minecraft 1.21.4 Fabric with Sodium, Iris, and Modern UI in a normal singleplayer world, with shader packs disabled and the creative inventory open.
• minecraft-1.21.4-fabric-iris-bsl-in-world: captured from Minecraft 1.21.4 Fabric with Sodium, Iris, and BSL Shaders after entering a singleplayer world.
• minecraft-1.21.4-fabric-iris-bsl-esc-menu-854: captured on an Android device (Mali-G77, FCL MobileGL capture) from Minecraft 1.21.4 Fabric with Sodium, Iris, and BSL Shaders, at the pause menu over a BSL-blurred world. The frame pins glyph rendering: every menu label, the menu title and the tutorial toast must be present. Regressions in the DirectGLES per-draw texture memo have made the whole text path disappear here while sprites kept rendering, so a failure that leaves the buttons but empties them is the signature to look for in the diff.
• minecraft-1.21.4-fabric-iris-makeup-ultrafast-in-world: captured from Minecraft 1.21.4 Fabric with Sodium, Iris, and MakeUP UltraFast after entering a singleplayer world.
• minecraft-1.21.4-fabric-iris-super-duper-vanilla-in-world: captured from Minecraft 1.21.4 Fabric with Sodium, Iris, and Super Duper Vanilla after entering a singleplayer world.
• minecraft-1.21.4-fabric-iris-complementary-reimagined-in-world: captured from Minecraft 1.21.4 Fabric with Sodium, Iris, and Complementary Reimagined after entering a singleplayer world.
• minecraft-1.21.4-fabric-iris-complementary-unbound-in-world: captured from Minecraft 1.21.4 Fabric with Sodium, Iris, and Complementary Unbound after entering a singleplayer world.
• minecraft-1.21.4-fabric-iris-mellow-in-world: captured from Minecraft 1.21.4 Fabric with Sodium, Iris, and Mellow after entering a singleplayer world.
• minecraft-1.21.4-fabric-iris-nostalgia-in-world: captured from Minecraft 1.21.4 Fabric with Sodium, Iris, and Nostalgia after entering a singleplayer world.
• minecraft-1.21.4-fabric-iris-bliss-in-world: captured from Minecraft 1.21.4 Fabric with Sodium, Iris, and Bliss after entering a singleplayer world.
• minecraft-1.21.4-fabric-iris-chocapic-v6-lite-in-world: captured from Minecraft 1.21.4 Fabric with Sodium, Iris, and Chocapic V6 Lite after entering a singleplayer world.
• minecraft-1.21.4-fabric-iris-iterationt-in-world: captured from Minecraft 1.21.4 Fabric with Sodium, Iris, and iterationT after entering a singleplayer world.
• minecraft-1.21.4-fabric-iris-iterationt-nodsa-in-world: captured from Minecraft 1.21.4 Fabric with Sodium, Iris, and iterationT after entering a singleplayer world, with Iris' DSA path disabled.
• minecraft-1.21.4-fabric-iris-iterationrp-in-world: captured from Minecraft 1.21.4 Fabric with Sodium, Iris, and iterationRP after entering a singleplayer world, framing the iterationRP name overlay over a lake with far-shore tree reflections. iterationRP's temporal auto-exposure makes a single-frame trim overexpose and drop the overlay, so the fixture is a prefix trace (all calls up to the target frame) that replays the temporal state. The pack also gates an NVIDIA-only shadow path (subgroupPartitionNV, GL_NV_shader_subgroup_partitioned) on the GL vendor string, so the capture reports a masked vendor and the trace carries the portable subgroupShuffleXor path that non-NVIDIA GPUs take. The trace archive and golden are not committed yet (the repository's Git LFS quota rejects new objects with GH009); the case stays registered and its fixture files are hydrated from the trace fixture mirror.
• minecraft-1.21.4-fabric-iris-photon-v1.1-in-world: captured from Minecraft 1.21.4 Fabric with Sodium, Iris, and Photon v1.1 after entering a singleplayer world.
• minecraft-1.21.4-fabric-iris-photon-v1.3b-in-world: captured from Minecraft 1.21.4 Fabric with Sodium, Iris, and Photon v1.3b after entering a singleplayer world.
• minecraft-1.21.4-fabric-iris-derivative-main-d24.4.14-in-world: captured from Minecraft 1.21.4 Fabric with Sodium, Iris, and Derivative Main d24.4.14 after entering a singleplayer world.
• minecraft-1.21.4-fabric-iris-sundial-lite-in-world: captured from Minecraft 1.21.4 Fabric with Sodium, Iris, and Sundial Lite after entering a singleplayer world.
• minecraft-1.21.1-neoforge-create-indirect-in-world: captured from Minecraft 1.21.1 NeoForge with Create, Sodium, and Iris (no shader pack) in a world facing Create water wheels and a large cogwheel, with Flywheel's flywheel:indirect backend (compute-shader culling, glMultiDrawElementsIndirect, persistent-mapped staging).
• minecraft-1.21.1-neoforge-create-instancing-in-world: same world and camera as the indirect case, with Flywheel's flywheel:instancing backend (texture-buffer instance data, glDrawElementsInstancedBaseVertex).

Build from the MobileGL repository root:

cmake -S . -B build-test -G Ninja \
  -DMOBILEGL_BUILD_TEST=ON \
  -DMOBILEGL_BUILD_BENCHMARK=OFF \
  -DMOBILEGL_BUILD_TRACE_REPLAY=ON
cmake --build build-test

Run the fixture tests:

ctest --test-dir build-test -V -R 'MobileGLTraceReplay\.'

Run the CLI directly:

build-test/tools/trace_replay/mobilegl_trace_replay \
  --trace openra.trace \
  --golden openra.0000031249.png \
  --output out/openra \
  --backend DirectGLES \
  --mobilegl-library build-test/libMobileGL.so \
  --target-call 31249 \
  --width 640 \
  --height 480 \
  --crop-x 1 \
  --crop-y 1 \
  --crop-width 638 \
  --crop-height 478 \
  --ssim-threshold 0.99

Dumping framebuffer attachments mid-frame

--target-call snapshots one framebuffer. To see inside a frame - which intermediate render target a pass actually produced - pass --dump-fbo-attachments CALL:DIR[:FBO,FBO,...], repeatably:

build-test/tools/trace_replay/mobilegl_trace_replay \
  --trace trace.trace --golden golden.png --output out --target-call 2667619 \
  --dump-fbo-attachments 2666231:out/fbos-before \
  --dump-fbo-attachments 2666232:out/fbos-after

At each call boundary it walks every live framebuffer object (or only the named ones), reads back every colour attachment and the depth attachment, and writes fbo<N>-att<M>.png / fbo<N>-depth.png plus a manifest.txt line per attachment recording the attached object, size, internal format, component type and per-channel min/max/mean and a content hash. Attachments are read as floats whatever their storage, so HDR accumulation buffers stay legible in the statistics even though the PNG has to clamp.

The manifest is the useful part when comparing two drivers: dump the same call on both stacks and diff/paste the two manifests, and the first attachment whose hash differs names the pass that diverged. Read-side and pixel-pack state is saved and restored, so the replay continues unperturbed; without the flag nothing is installed and the replay is byte-for-byte what it was.

Run the macOS native-window DirectVulkan retrace matrix and render the same HTML overview shape as CI:

cmake -S . -B cmake-build-macos-trace-arm64 -G Ninja \
  -DCMAKE_BUILD_TYPE=Release \
  -DCMAKE_OSX_ARCHITECTURES=arm64 \
  -DMOBILEGL_BUILD_TEST=OFF \
  -DMOBILEGL_BUILD_BENCHMARK=OFF \
  -DMOBILEGL_BUILD_TRACE_REPLAY=ON
cmake --build cmake-build-macos-trace-arm64 --target MobileGL mobilegl_trace_replay
python3 tools/trace_replay/run_macos_window_retrace_local.py --ci --all
open .trace-work/macos-window-retrace-summary/mobilegl-macos-window-vulkan-retrace-overview.html

The macOS runner hydrates missing fixtures from the trace fixture mirror with parallel downloads before falling back to Git LFS. It reuses the cmake-build-macos-trace-arm64 harness by default on Apple Silicon, passes --window-surface, and defaults to DirectVulkan only. If a native-window replay hits a fatal assertion, the runner writes a failure result and stops before launching later cases; use --continue-after-fatal to collect the full matrix, or --skip-case NAME for known fatal cases.

Android device replay

Build and install the generic trace APK from the repository root. Both DirectGLES and DirectVulkan use the same APK and package; select the backend with the intent's backend extra.

gradle --no-daemon -p android-plugin :app:assembleTraceDebug
TRACE_APK=$(find android-plugin/app/build/outputs/apk/trace/debug -maxdepth 1 -name '*.apk' -print -quit)
adb install -r "$TRACE_APK"

Prepare a fixture and copy it into the app-private directory:

mkdir -p /tmp/mobilegl-openra
tar -xzf tools/trace_replay/fixtures/openra.tgz -C /tmp/mobilegl-openra
adb push /tmp/mobilegl-openra/openra.trace /data/local/tmp/mobilegl-openra.trace
adb push tools/trace_replay/fixtures/openra.0000031249.png /data/local/tmp/mobilegl-openra.golden.png

PKG=top.mobilegl.plugin.trace
APP_DIR=/data/user/0/$PKG/files/trace-replay
adb shell run-as $PKG rm -rf files/trace-replay
adb shell run-as $PKG mkdir -p files/trace-replay/input files/trace-replay/output
adb shell run-as $PKG cp /data/local/tmp/mobilegl-openra.trace files/trace-replay/input/openra.trace
adb shell run-as $PKG cp /data/local/tmp/mobilegl-openra.golden.png files/trace-replay/input/openra.golden.png

Launch the standalone trace runner Activity:

adb shell am force-stop $PKG
adb shell am start -W -a top.mobilegl.plugin.TRACE_REPLAY \
  -n $PKG/top.mobilegl.plugin.trace.TraceReplayActivity \
  --es trace_path $APP_DIR/input/openra.trace \
  --es golden_path $APP_DIR/input/openra.golden.png \
  --es output_dir $APP_DIR/output \
  --es diff_path $APP_DIR/output/openra-diff.png \
  --es backend DirectGLES \
  --el target_call 31249 \
  --ei width 640 \
  --ei height 480 \
  --ei crop_x 1 \
  --ei crop_y 1 \
  --ei crop_width 638 \
  --ei crop_height 478 \
  --es ssim_threshold 0.99

Read back the result and images:

adb shell run-as $PKG cat files/trace-replay/output/result.json
adb exec-out run-as $PKG cat files/trace-replay/output/actual.png > openra-actual.png
adb exec-out run-as $PKG cat files/trace-replay/output/openra-diff.png > openra-diff.png

For Vulkan replay, keep the same APK and $PKG, then pass --es backend DirectVulkan. DirectGLES also renders to the Activity surface by default; pass --ez use_pbuffer true to use the offscreen pbuffer path. Always adb shell am force-stop $PKG before another replay: apitrace snapshot state is process-local. For cases registered with coherent_as_flush (Flywheel-style unflushed persistent maps, e.g. the Create fixtures), pass --ez coherent_as_flush true so the replay runs with MOBILEGL_COHERENT_AS_FLUSH=1. For cases registered with avoid_angle_llvmpipe_explicit_lod_bias (DirectGLES on ANGLE llvmpipe, e.g. the sundial-lite fixture), pass --ez avoid_angle_llvmpipe_explicit_lod_bias true so the replay runs with MOBILEGL_ESPRYT_AVOID_EXPLICIT_LOD_BIAS=1.

Benchmark mode (frame timing)

Benchmark mode reuses the same fixtures as a performance harness instead of a correctness one: it replays the trace from the first call to the last, takes a wall-clock timestamp at every frame boundary, and takes no snapshot and runs no SSIM comparison. passed then only means the replay reached the end of the trace without an error.

Frame times include GPU completion by default, because a swap boundary on a tiled mobile GPU returns long before the tiler is done and would otherwise time CPU submission alone. That is what benchmark_finish / --benchmark-finish controls: on (the default) it issues a glFinish through the replayed context at every frame boundary, which serializes CPU/GPU overlap - pessimistic against a real running game, but deterministic and comparable between backends and revisions. Turn it off to measure CPU-side submission only.

The mean/median/p95 are computed over the last benchmark_tail_frames frames (default 200, clamped to the frames actually recorded); the head of a trace is dominated by shader compiles and first-use uploads. The full per-frame array is in the timing JSON, next to the headline numbers, which also appear in result.json.

Whole device runs, one line per run plus the best of the repeats:

python tools/trace_replay/run_android_retrace_local.py --benchmark \
  --case minecraft-1.21.4-fabric-iris-photon-in-world --backend DirectVulkan \
  --benchmark-repeats 3

--benchmark-tail-frames N, --benchmark-no-finish and --benchmark-timeout-seconds N are available; only the first repeat installs the APK and pushes the trace. Each run's benchmark.json is kept next to the case result as benchmark-run<N>.json.

The Activity takes the same settings directly:

adb shell am start -a top.mobilegl.plugin.TRACE_REPLAY \
  -n $PKG/top.mobilegl.plugin.trace.TraceReplayActivity \
  --es trace_path $APP_DIR/input/openra.trace \
  --es output_dir $APP_DIR/output \
  --es backend DirectGLES \
  --ei width 640 --ei height 480 \
  --ez benchmark true \
  --ei benchmark_tail_frames 200 \
  --ez benchmark_finish true \
  --es benchmark_result_path $APP_DIR/output/benchmark.json
adb exec-out run-as $PKG cat files/trace-replay/output/benchmark.json > benchmark.json

golden_path and target_call are not needed in benchmark mode. The Linux CLI takes the same options:

./mobilegl_trace_replay --trace openra.trace --output out --backend DirectGLES \
  --benchmark --benchmark-tail-frames=200 --benchmark-finish=1 \
  --benchmark-result=out/benchmark.json

Two caveats when reading the numbers. Frame times are taken at eglSwapBuffers, so a trace that ends frames with glFrameTerminatorGREMEDY instead is not timed. And on a window surface the swap can block on the compositor, which pins frame times to the display refresh; replay against the pbuffer surface (--ez use_pbuffer true) to measure the renderer rather than the presentation path.

Reproducing the Android DirectGLES lane on Linux (ANGLE on lavapipe)

The APK workflow's DirectGLES lane is not the same stack as the Linux one, which is why a case can be green here and red there:

lane	stack
Linux Test retrace, DirectGLES	Espryt -> Mesa GLES -> llvmpipe
Android APK retrace, DirectGLES	Espryt -> ANGLE -> Mesa Vulkan (lavapipe)
Android APK retrace, DirectVulkan	Magma -> lavapipe (no ANGLE)

Only the Android DirectGLES lane puts ANGLE in the middle, so an ANGLE translation difference shows up in exactly one of the six combinations. That stack can be reproduced on Linux without an emulator, which is far faster to iterate on than a CI round trip. The Android emulator SDK ships a glibc ANGLE:

ANGLE=$ANDROID_SDK_ROOT/emulator/lib64/gles_angle
mkdir -p ~/angle-farm && cd ~/angle-farm
# MobileGL dlopens these two names; ANGLE's own libEGL then dlopens the
# unsuffixed libGLESv2.so from the same directory - without that symlink it
# loads a truncated entry-point table and dies on a missing EGL function.
ln -sf $ANGLE/libEGL.so    libEGL_angle.so
ln -sf $ANGLE/libGLESv2.so libGLESv2_angle.so
ln -sf $ANGLE/libEGL.so    libEGL.so
ln -sf $ANGLE/libGLESv2.so libGLESv2.so
ln -sf $ANGLE/libvulkan.so.1 libvulkan.so.1   # else eglInitialize fails

MOBILEGL_ESPRYT_USE_ANGLE=1 \
LD_LIBRARY_PATH=~/angle-farm:/path/to/build/ \
VK_ICD_FILENAMES=/usr/share/vulkan/icd.d/lvp_icd.json \
ANGLE_DEFAULT_PLATFORM=vulkan \
  ./mobilegl_trace_replay --trace trace.trace --golden golden.png \
    --target-call N --width 854 --height 480 --backend DirectGLES \
    --output outdir --pbuffer-surface

ANGLE_DEFAULT_PLATFORM=vulkan is required: ANGLE otherwise picks its OpenGL backend and you get ANGLE (Mesa, llvmpipe ..., OpenGL 4.6 (Core Profile)) instead of the CI-shaped ANGLE (Mesa, Vulkan 1.x (llvmpipe ...)). Check MOBILEGL_TRACE_GL_RENDERER in outdir/retrace.log before trusting a result. Run the binary directly rather than through ctest, whose ENVIRONMENT property overrides these variables. Build with clang, not gcc: gcc rejects GLXImpl.cpp under -Wchanges-meaning.

One more caveat before attributing anything: the emulator SDK's ANGLE is not the ANGLE the Android lane runs. The CI lane uses a pinned build (MOBILEGL_TRACE_ANGLE_VARIANT, default ec889e6ea831) whose version and extension set differ from the SDK copy (GL_EXT_texture_buffer support, ES 3.2 entry points). Compare GL_RENDERER and the relevant extension lists on both stacks before treating a local result as a statement about CI.