wave 0 item 5. Three instruments P7's device window needs, and the CI steps that
can make each of them red.
run_tcp_matrix.py --backend DirectVulkan end to end. --backend already existed and
already filtered by each case's ci_backends; what did not exist is a per-backend
GOLDEN. The two backends shared `golden` plus an optional `alternate_golden`, and
alternate_golden is an OR across backends, not a per-backend key - so a
DirectVulkan run that matched the DirectGLES picture passed, which is the "went
green on the wrong arm" shape the exit gate exists to catch. trace_cases.json
gains `backend_overrides.<backend>` ({golden, alternate_golden, ssim_threshold}
only: restating target_call or a crop would stop the two backends retracing the
same frame through the same window). A per-backend golden REPLACES the shared
pair, matching another backend's declared image is refused BY NAME, and a --case
named explicitly that does not run a requested backend is an error instead of one
plan fewer and no message. The CMake emitter and the APK matrix refuse a case that
declares the key rather than silently emitting one golden for both arms.
DirectGLES is unchanged and that is asserted, not asserted-in-prose: a case with no
override resolves to itself, and the key is dropped from the resolved case even for
the backend that overrides nothing - so giving DirectVulkan its own golden does not
move the DirectGLES identity fingerprint and does not invalidate its checkpoints.
Each results.json row now records the golden, alternate golden and threshold it was
scored against.
run_android_retrace_local.py gets --matrix (the CI split subset, 39 cases, each
running only its own ci_backends - not --all, which adds the rd12 workload ID-P7-4
excludes), --repeat N, and --archive-dir. The archive is the point: the result root
is keyed by case and backend and by NOTHING else, so repeat 2 overwrites repeat 1
and the only artefact that survives a three-repeat run is the last one, which makes
"were the three repeats the same picture?" unanswerable after the fact - in the one
place where re-running to find out is expensive. It also refuses --benchmark with a
non-monolith --transport, which has always produced a monolith run under a spawn
label (run_benchmark_case passes args.env alone; p6/README.md records the pitfall).
compare_actuals.py computes the pair result.json cannot: SSIM between two actual
PNGs, plus a case x repeat x ssim-vs-golden x ssim-vs-first-repeat table over an
archive. It is the retrace gate's OWN SSIM - a transcription of ComputeChannelSsim
/ ComputeRgbSsim (trace_replay_core.cpp:630/:671), the only SSIM in the tree - and
the crop comes from each repeat's own result.json, so the two columns describe the
same rectangle. PNG decode is stdlib zlib, because an unavailable Pillow in the
device window would turn "the repeats diverged" into "the tool did not run".
TraceReplayActivity: resolveSpawnServerPath's two decisions were String.contains()
on the whole joined K=V;K=V list and neither was entry-aware. The one that bit:
`--env MOBILEGL_IPC_SERVER_PATH` with no '=' is the documented UNSET spelling
(trace_env_overrides_test.cpp:92) and the only way to ask for "spawn with no image"
and watch LaunchServer refuse by name - it did not match "MOBILEGL_IPC_SERVER_PATH="
so a resolved path was appended AFTER it and, because ApplyEnvOverrides applies in
order with setenv(...,1), the deliberate unset was silently undone. That is exactly
the "silently replacing it would make that knob untestable" the method's own comment
forbids. Two more: the key inside another entry's VALUE flipped both decisions the
wrong way, and the transport match was case-sensitive while ConfigLoader lower-cases
the value before matching (ConfigLoader.cpp:322). The parse moves to
SpawnServerPath, a class with no android.* import, so test_android_lifecycle.py
compiles and runs it with plain javac - the parse had no host-side coverage at all,
and its on-device failure mode is "the knob had no effect".
Only spawn gets a path, deliberately: it is the only transport that execs an image.
Red-once, all four: a stub case whose result names the DirectGLES golden fails a
--backend DirectVulkan run with "matched a golden another backend declares"; a
synthetic PNG pair with a closed-form SSIM (identical = 1.0 exactly, constant
black vs white = C1/(255^2+C1), inverted halves = (C2-2v)/(2v+C2)); the pre-fix
resolveSpawnServerPath body fails eight of SpawnServerPathTest's checks; and the
DirectVulkan TCP proof battery is the DirectGLES one under the other prefix,
because an empty prefix selection raises nothing and reads as a clean pass.
CI: test_run_tcp_matrix.py and test_compare_actuals.py join the R-16 step. The
matrix driver's stub regressions had NO CI step - they were run by hand and
recorded in a note - and they guard the tool that decides whether a device golden
run passed.
Counts in WSL: test_run_tcp_matrix 12 -> 18, tcp_lane_tools 4 -> 6,
test_compare_actuals 12 new, test_android_lifecycle green with the new Java unit.
MobileGL
A desktop OpenGL implementation
MobileGL is a free and open-source project that implements a desktop OpenGL API. The goal is to provide a complete desktop OpenGL implementation with a state management layer and multi-backend support.
Note
Status: In development. Parts of the codebase are incomplete. Current short-term target: OpenGL 4.2 (Core Profile).
Project positioning
MobileGL is an implementation of a desktop OpenGL library. It aims to provide:
- Full OpenGL state management.
- A front-end that exposes OpenGL functions.
- Multiple independent backend implementations, where each backend targets a specific graphics API and remains fully isolated from others.
This project is intended as an implementation/translation layer.
Key components
The repository is organized into following top-level modules:
- MG_State — state tracking and management logic for Graphics APIs.
- MG_Impl — front-end implementations of Graphics APIs that interact with
MG_StateandMG_Backend. - MG_Backend — per-backend translation layer that maps front-end Graphics APIs' semantics and state into concrete backend API calls (e.g. OpenGL ES, Vulkan).
- MG_Util and other utility modules.
Third-party components
MobileGL reuses several open-source projects:
- SPIRV-Cross by KhronosGroup - Apache License 2.0: github
- glslang by KhronosGroup - Various Licenses: github
- DiligentCore by Diligent Graphics - Apache License 2.0: github
- flat_hash_map by Malte Skarupke - Boost Software License 1.0: github
Refer to each component's repository for exact license texts. Any bundled third-party code in this repository is included under the upstream project's license.
Compatibility & target
- Short-term target:
OpenGL 4.2 (Core Profile). - Current development focus:
- Performance improvement
MG_StateandMG_ImplforOpenGL 4.2 (Core Profile)Direct (Vulkan)backendDirect (OpenGL ES)backend
Build Instructions
We currently provide no releases and no precompiled binaries.
If you want to try the project right now, you’ll need to build it yourself:
-
Clone the repository:
git clone https://github.com/MobileGL-Dev/MobileGL.git -
Initialize and update all submodules recursively:
git submodule update --init --recursive -
Follow glslang’s own documentation for its required initiation.
-
Configure and build the project with CMake:
cmake -B build cmake --build buildor do it in a modern way:
cmake -S . -B build -G Ninja -DCMAKE_C_COMPILER=clang -DCMAKE_CXX_COMPILER=clang++ cmake --build buildAlternatively, you can use platform-specific build commands as needed.
Build For macOS
On macOS, MobileGL can be built as a dylib that exposes the normal OpenGL/CGL/NSOpenGL entry points and routes them to the DirectVulkan backend. This is useful for running applications such as Minecraft through their stock GLFW/LWJGL OpenGL path while MobileGL is injected before context creation.
Prerequisites:
- macOS with Clang and Ninja.
- Vulkan loader and MoltenVK installed. With Homebrew, the MoltenVK ICD is commonly located at
/opt/homebrew/etc/vulkan/icd.d/MoltenVK_icd.json.
Configure and build:
cmake -S . -B build-macos-magma \
-G Ninja \
-DCMAKE_BUILD_TYPE=Release \
-DMOBILEGL_BACKEND_TYPE=DirectVulkan \
-DMOBILEGL_BUILD_TEST=OFF \
-DMOBILEGL_BUILD_BENCHMARK=OFF
cmake --build build-macos-magma --target MobileGL -j8
The dylib will be generated at:
build-macos-magma/libMobileGL.dylib
To run Minecraft by MobileGL from a launcher like PrismLauncher, keep the stock LWJGL/GLFW natives and add a wrapper command to the instance settings:
env DYLD_INSERT_LIBRARIES=/absolute/path/to/MobileGL/build-macos-magma/libMobileGL.dylib MOBILEGL_BACKEND_TYPE=DirectVulkan VK_ICD_FILENAMES=/opt/homebrew/etc/vulkan/icd.d/MoltenVK_icd.json
Also make sure the JVM arguments include:
-XstartOnFirstThread
DYLD_INSERT_LIBRARIES must be active before GLFW creates its OpenGL context. After startup, the Minecraft F3 screen should report MobileGL and the Direct (Vulkan) backend if the injection worked.
Build Options
| Option | Description | Default |
|---|---|---|
MOBILEGL_BUILD_TEST |
Build MobileGL tests (requires Clang) | ON |
MOBILEGL_BUILD_BENCHMARK |
Build MobileGL benchmarks (requires Clang) | ON |
MOBILEGL_FORCE_RELEASE_OPT |
Enable O3 and LTO in Debug build | ON |
MOBILEGL_ENABLE_TRACY |
Enable Tracy profiler for performance analysis | OFF |
Notes:
- The project requires C++23.
MG_TestandMG_Benchmarkcan only be built with Clang, not GCC. To enforce Clang, add-DCMAKE_C_COMPILER=clang -DCMAKE_CXX_COMPILER=clang++to your command.- On Android, tests and benchmarks are always disabled.
Environment Variables
MobileGL supports runtime configuration via environment variables.
Supported Keys
| Variable | Description | Allowed Values | Default |
|---|---|---|---|
MOBILEGL_BACKEND_TYPE |
Select active backend implementation at startup. | DirectGLES, DirectVulkan |
DirectGLES |
MOBILEGL_DISABLE_TIMERQUERY |
Disable GPU timer-query exposure and use. | 0, 1 |
0 |
MOBILEGL_ESPRYT_USE_ANGLE |
Load ANGLE EGL/GLES libraries. | 0, 1 |
0 |
MOBILEGL_MAGMA_DISABLE_SUBGROUP |
Disable Vulkan shader subgroup support. | 0, 1 |
0 |
MOBILEGL_ADVERTISE_FP64 |
Advertise GL_ARB_gpu_shader_fp64. GLSL double/dvec/dmat compile and run either way - they are narrowed to 32 bits - so this only changes whether an application is told it has 64-bit precision, which it does not. |
0, 1 |
0 |
MOBILEGL_MAGMA_R11G11B10F_FALLBACK |
Use Magma's R11G11B10F format fallback. | 0, 1 |
0 |
MOBILEGL_MAGMA_FRAMESINFLIGHT |
Set Magma frames in flight. | Integer 1–64 |
3 |
MOBILEGL_ESPRYT_AVOID_SAMPLER_MIPMAP_MIN_FILTER |
Avoid sampler mipmap minification filters. | 0, 1 |
0 |
MOBILEGL_COHERENT_AS_FLUSH |
Treat persistent GL_MAP_FLUSH_EXPLICIT_BIT maps as coherent (app-compat for engines like Flywheel that never flush them). |
0, 1 |
0 |
MOBILEGL_ESPRYT_FORCE_DS_READBACK_EMULATION |
Always emulate depth/stencil glReadPixels/glGetTexImage by shader sampling on Espryt, instead of using the driver's own depth/stencil readback where it has one. |
0, 1 |
0 |
VK_ICD_FILENAMES |
Select the Vulkan ICD used by the Vulkan loader. | Path to an ICD JSON file | Loader default |
License
This project is distributed under GNU LGPL v3.0. See the LICENSE file in the repository for detailed information.