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- PLAN-B.md §11 P0 lists spike A (the Android delivery chain) as a P0 deliverable, inherited verbatim from PLAN.md §15 P0; §8.1 inherits PLAN.md §11.1-§11.6, whose Android path needs a second process. Android gives an application no writable exec-able directory, so the only supported route is to name the binary lib*.so, let the packager put it in lib/<abi>/, and exec it out of getApplicationInfo().nativeLibraryDir. This builds that route end to end so the spike can be answered with evidence instead of folklore. - New root option MOBILEGL_BUILD_SERVER_SPIKE (OFF, ANDROID-only) adds the MobileGLServer target from tools/spikes/server_stub/main.cpp with PREFIX "lib" / SUFFIX ".so" and -fPIE/-pie: an .so name does not exempt the file from Android's PIE requirement. Its RUNTIME_OUTPUT_DIRECTORY is pointed at CMAKE_LIBRARY_OUTPUT_DIRECTORY, because AGP packages what lands in the per-ABI library output directory and CMake would otherwise put an executable elsewhere. - The option is opt-in on both sides. The plugin flavour cannot turn it on at all, and the trace flavour builds it only when asked, with `-Pmobilegl.buildServerSpike=ON` or MOBILEGL_BUILD_SERVER_SPIKE=ON in the environment; a flavour that silently carries an executable nothing loads is the kind of thing nobody notices until it ships. Verified both ways: assembleTraceDebug -Pmobilegl.buildServerSpike=ON packages lib/arm64-v8a/libMobileGLServer.so and `file` reports "ELF 64-bit LSB pie executable, ARM aarch64 ... interpreter /system/bin/linker64, for Android 26"; the same task with no property packages only libMobileGL.so and libtrace_replay_runner.so. - The stub prints one line to stdout and writes the same line to the file named by argv[1], then exits 0. The line carries pid/ppid/uid/gid and, decisively, the child's own /proc/self/attr/current: only `u:r:untrusted_app:...` proves an ordinary app process did the exec. An `adb run-as` shell runs in a different SELinux domain, so a success there would prove nothing. - RunSpawnSpike() starts the stub with argv [serverPath, markerPath], redirects the child's stdout/stderr into a captured file (an app process has stdout on /dev/null, so a printed line would otherwise vanish), waits for it, and reports exit status, signal, the exec errno, the parent's own SELinux context, the marker content and the captured stdout - to logcat, to the returned string, and to a <marker>.report file, because the Activity finishes immediately afterwards. - The child reports the errno of a REFUSED execve through a close-on-exec pipe. Without it the one datum the spike exists to produce is lost: the parent only ever sees a wait status, in which every reason has already been flattened into one exit code, and EACCES (SELinux, or a noexec mount) versus ENOEXEC (a packager that mangled the file) are opposite verdicts for the design. A successful exec closes the write end for free, so the parent reads EOF and reports execErrno=0. - fork/execve only. The earlier draft also carried a posix_spawn arm behind `__ANDROID_API__ >= 28`, which was dead code in every configuration this repo can build - bionic declares posix_spawn from API 28 and the root CMakeLists.txt pins MOBILEGL_ANDROID_API_LEVEL to 26 and refuses to configure lower - and would have silently become the production path, untested, on a minSdk bump. Keeping the arm that actually ships means the spike measures the code the server would really use. Nothing happens between fork and execve except open/dup2/execve/write/_exit, all async-signal-safe, because the parent is a multi-threaded JVM process. - The spike lives in its own TU, spawn_spike.cpp/.hpp, listed only by the trace APK's CMakeLists. Its sibling trace_replay_core.cpp is compiled verbatim by the DESKTOP mobilegl_trace_replay runner (tools/trace_replay/CMakeLists.txt names the same file), where <android/log.h> does not exist, so nothing Android-only may live there; spawn_spike.cpp carries an #error for anyone who adds it to that list. - The Activity runs the spike, and nothing else, when launched with the `mobilegl_spike_spawn` intent extra; that mode needs no trace, no golden and no render surface. It is a separate JNI entry point rather than another parameter on the 30-argument replay call, which it shares nothing with. - Not yet run on a device: both device locks are held by another campaign. The on-device verdict is the coordinator's step.
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.