BZLZHH
42fd02d82f
The binding-point half of ARB_vertex_attrib_binding was implemented, but nothing
outside it could see the result. glGetIntegerv answered GL_MAX_VERTEX_ATTRIB_BINDINGS,
GL_MAX_VERTEX_ATTRIB_RELATIVE_OFFSET and GL_MAX_VERTEX_ATTRIB_STRIDE with a hardcoded
0 and a comment saying the entry points were stubs, which they no longer are. An
application that sizes its loops off those limits therefore saw none, and every
"bindingindex must be less than MAX_VERTEX_ATTRIB_BINDINGS" check silently accepted
everything because the limit it validated against was not the one it reported.
The indexed getters answer GL_VERTEX_BINDING_{BUFFER,DIVISOR,OFFSET,STRIDE} from the
bound vertex array now, and the non-indexed getter reports them as indexed-only rather
than returning a fabricated 0.
glVertexAttribPointer is defined in terms of the binding model: it also points the
attribute at its own binding point and gives that point the buffer, the pointer as the
offset and the effective (never zero) stride. MobileGL resolved the pointer form
straight into the flat attribute view and left the binding point untouched, so
GL_VERTEX_BINDING_OFFSET read back 0 for every attribute set up the classic way. The
flat view keeps the raw stride, because GL_VERTEX_ATTRIB_ARRAY_STRIDE reports that
argument verbatim, so the binding point is recorded alongside it rather than resolved
from it. glVertexAttribDivisor likewise now moves the binding point's divisor.
The by-name entry points reject vertex array 0. MobileGL keeps a real object at index 0
for the compatibility paths, so the name validation used to let the default vertex array
through a direct-state-access call that has no such thing.
glVertexAttribFormat and friends validated with the pointer-only subset, which reports
GL_BGRA as an out-of-range size instead of applying the BGRA rules, and never saw
relativeoffset at all. They share the full format validation now, which also grew the
GL_UNSIGNED_INT_10F_11F_11F_REV rules - that type has no DataType of its own, so it has
to be recognised before the conversion turns it into Unknown and reports the wrong error.
glVertexAttribLFormat and glVertexArrayAttribLFormat were stubs. They validate their
arguments now and then report that 64-bit vertex attributes are unsupported, which is
honest; silently accepting a format that can never be used is not.
Takes direct_state_access.vertex_arrays_* from 12 to 17 of 19 on both backends.
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 3.3 (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
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 3.3 (Core Profile). - Current development focus:
MG_StateandMG_ImplforOpenGL 3.3 (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_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 |
VK_ICD_FILENAMES |
Select the Vulkan ICD used by the Vulkan loader. | Path to an ICD JSON file | Loader default |
Notice
- MobileGL is not production-ready currently.
- Some
OpenGL 3.3 (Core Profile)features are still missing or under development.
License
This project is distributed under GNU LGPL v3.0. See the LICENSE file in the repository for detailed information.