swung0x48
281467a345
Audit of every memoization implementation; sixteen verified defects fixed: DirectGLES backend: - Broadcast draw-buffer memo: cleared at MakeCurrent/DestroyEGLContext like its sibling shadows; its identity+version key is only monotonic within one GLContext, so a library teardown + re-init could false-hit on a recycled FBO address. - Backend texture id re-mint (RecreateBackendTexture) now bumps an attachment generation that the SyncCurrentFBO gate and every FBO twin compare, so driver FBOs re-attach instead of keeping the deleted texture name; the attachment walk re-enters until the generation is quiescent (a walk itself can re-mint). - Buffer id re-mint (persistent-map adoption, immutable-store retire) now bumps a generation the VAO twin sync compares, forcing a full re-emit of the baked glVertexAttribPointer / element-array bindings that frontend versions cannot see. - VAO element-array sync memo: bound-object identity joins the wrapping Uint16 slot version (same pairing the ResolvedDrawBuffers IBO memo already uses). DirectVulkan backend: - EBO slice memo gains the mapped-buffer guard its vertex-binding sibling has: a shadow-backed persistent map mutates with no epoch bump, so a hit must decline. - VkClearManager::MergeClearPayload keeps colorEncoding/colorInt/colorUint with the color, so deferred glClearBufferiv/uiv no longer degrade to all-zero float. - GetOrCreateComputePipeline no longer memoizes a failed creation (same contract as PipelineFactory): a transient driver failure was permanently disabling every dispatch of that program. - Explicit-LOD-0 verdict memo keys on the sampling-resolution generation; sampler filter/aniso/LOD setters bump only that counter, so the old key served a stale verdict (wrong SPIR-V variant) after glTexParameter/glSamplerParameter changes. - SetupDraw fast path declines instead of re-arming on a moved sampling-resolution generation (the snapshot bakes the LOD verdict into its pipeline), and recomputes the XfbCapture bit so the first draw after glBeginTransformFeedback cannot bind the undecorated variant and silently capture nothing. - VertexInputStateFactory eviction epoch is drawn from a process-wide source: VAO state-pointer memos outlive the factory across renderer recreation, and a fresh factory restarting at epoch 1 would dereference a dead factory's entry. - Cached render passes re-read the live renderbuffer clear payload at begin (the clear VALUE is not in the pass hash; the entry's inline snapshot replayed the creation-time color and dropped the newly queued one). - FramebufferObject gains a never-reused lifetime id, keyed into the render-pass fast-path memo and the SetupDraw snapshot beside the raw pointer + Uint16 version pair, which address reuse plus fresh version counts could equal. - SyncTextureResource's preserved-content image goes through the deferred-release ring on both failure paths instead of a synchronous destructor under the GPU. MG_State frontend: - Layer-1 compile memo is env-disciplined like layers 2/3: a node computed against a dead CompileEnv (e.g. pre-capability fallback limits) no longer answers glCompileShader forever once the environment's content changes. - Pipeline composite cache rebuilds from each stage program's last-link shader snapshot (new LinkedShaderRef list + pinned link inputs) instead of the live attach list and current compile nodes: post-link glAttachShader/glCompileShader must not leak into the composite while the (lifetimeId, linkVersion) signature still hits - GL's "as last linked" rule.
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_USE_ANGLE |
Load ANGLE EGL/GLES libraries. | 0, 1 |
0 |
MOBILEGL_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_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.