BZLZHH 313b75a7c0 [Test] (MG_IntegrationTest): pin the two shipped memo bugs with rendered pixels
Both d7976326 bugs passed every unit test while corrupting real frames -
state-level assertions cannot see them. This module renders and reads
back.

A headless EGL-pbuffer harness (no window, no GLFW) linking MobileGL_s
directly, registered once per backend under the ctest label
integration-gpu, behind the default-OFF option
MOBILEGL_BUILD_INTEGRATION_TEST. The platform pre-flight runs the ENTIRE
bring-up in a forked child first - MobileGL aborts rather than returning
errors on an unusable platform, and the child dying on any signal turns
into a clean GTEST_SKIP instead of taking the test binary down.
MOBILEGL_ITEST_REQUIRE_GPU makes the label falsifiable: with it set, an
unusable harness (or a context that lands on a software rasterizer) is a
FAILURE - without it, a CI runner whose driver pinning silently broke
reports the same green as one that rendered every frame. Configure-time
detection pins the EGL vendor and Vulkan ICD jsons, preferring hardware
vendors and never selecting llvmpipe/lavapipe.

Scenarios assert on glReadPixels with whole-region pixel counts (a
2x2 quadrant pattern whose signature distinguishes all eight square
symmetries; every region predicate reports the first offending pixel):
- OrientationScenario: default -> FBO -> default, pinning the
  transform-flags memo key. Keying GetBaseTransformFlagsRaw on the
  pre-transform alone fails exactly 3 entries.
- StreamedArenaScenario: an untouched streamed vertex buffer must
  survive transient-arena recycling. Re-enabling only the cross-frame
  vertex revalidation fails exactly this entry.
- CrossFrameBufferScenario + ResidentIndexScenario: cross-frame
  mutation matrix (SubData, map/unmap, persistent+flush, coherent
  persistent, orphan, CopyBufferSubData; vertex and index) plus six
  adversarial resident-EBO constructions. Instrumentation showed the
  cross-frame EBO memo cannot be made to serve wrong bytes from GL
  level on this stack (89 entries, 81 accepts, zero divergent slices) -
  these cases are freshness tripwires, documented as such in-file; the
  EBO half of d7976326 remains unpinned by a failing test.

At the buggy commit 72ee7c43 the suite fails 4 entries (3 orientation +
1 streamed-arena); at d7976326 all 52 pass, 5 consecutive runs, zero
flakes, and the default build is bit-for-bit unaffected (unit suite
unchanged). Adversarially verified twice, including hostile-platform
sweeps (26 configurations, all clean skips) and hand-edits of each
production hole in isolation.
2026-08-07 03:30:18 -04:00

MobileGL

C++ GNU LGPL 3.0 Development

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:

  1. MG_State — state tracking and management logic for Graphics APIs.
  2. MG_Impl — front-end implementations of Graphics APIs that interact with MG_State and MG_Backend.
  3. 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).
  4. MG_Util and other utility modules.

Third-party components

MobileGL reuses several open-source projects:

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_State and MG_Impl for OpenGL 4.2 (Core Profile)
    • Direct (Vulkan) backend
    • Direct (OpenGL ES) backend

Build Instructions

We currently provide no releases and no precompiled binaries.
If you want to try the project right now, youll need to build it yourself:

  1. Clone the repository:

    git clone https://github.com/MobileGL-Dev/MobileGL.git
    
  2. Initialize and update all submodules recursively:

    git submodule update --init --recursive
    
  3. Follow glslangs own documentation for its required initiation.

  4. Configure and build the project with CMake:

    cmake -B build
    cmake --build build
    

    or do it in a modern way:

    cmake -S . -B build -G Ninja -DCMAKE_C_COMPILER=clang -DCMAKE_CXX_COMPILER=clang++
    cmake --build build
    

    Alternatively, 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_Test and MG_Benchmark can 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_USE_ANGLE Load ANGLE EGL/GLES libraries. 0, 1 0
MOBILEGL_DISABLE_SUBGROUP Disable Vulkan shader subgroup support. 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 164 3
MOBILEGL_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
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.

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