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CONTRACT-P7 §5.3, OQ-8. MagmaProgramSource::EnsureStorageBlocks re-ran SPIRV-Reflect over
every stage module of the program PER DRAW: the class is a borrowed view that
WireDraw.inc's WireProgramSource constructs afresh for each wire draw, so its `mutable`
memo was cold every time it was read. The list it rebuilt is a pure function of the linked
program, so it is now built once at link time and travels in the archive.
LinkArtifacts gains storageBlocks{name, binding, dataSize} with its own VisitFields table,
the codec version goes 2 -> 3, and the schema fingerprint and wireFingerprint move with
it - which is expected, and is what makes a mixed-version pair refuse at the handshake
instead of at the first program.
FILLED IN PHASE A, and that is not where it looks like it belongs. The only function that
sees both finished halves is ProgramSpirvTask's L1 cache insert, but its writes reach the
TRANSLATION CACHE only: phase A's artifacts have already been moved into the ProgramObject
by then. A field filled there would be present on a cache hit and absent on every cold
link. So the fill is glslang-derived, and the equivalence is MEASURED rather than assumed:
ProgramTest.TheArchivesStorageBlockOrderIsTheOneSpirvReflectProduces runs the old
consumer's own algorithm over the real modules and compares element for element, on a
multi-stage program with an arrayed SSBO and an atomic-counter block - the three cases
that could have diverged (the instance array collapses to one entry, the synthesized
counter block IS in the backend's space although GL's enumeration excludes it, and the
cross-stage dedupe walks stages in linked order).
MEASURED, same binary and same window (frames=1 draws=1 acc=18, identical bytes),
DirectVulkan x inproc over the SSBO scenarios: spvReflectCreateShaderModule on the wire
draw path 4 -> 0. The 0 is structural: the call site is gone and MagmaProgramSource.h no
longer includes spirv_reflect.h at all, which is the gate a future edit breaks on purpose.
THE MONOLITH CONSUMER IS SWITCHED TOO, under #if symmetry, so the disaggregated build
retires g_programResourceCaches, ProgramResourceCache, StorageBlockResource,
BufferVariableResource, AddBufferVariablesRecursive, NormalizeDescriptorName,
GetProgramResourceCache and the rehash hazard - the open-addressed-map dangling reference
that was a reproducible segfault in ProgramPipelineScenario's two storage-block cases.
Nothing outside DirectVulkan.cpp read any of it (measured; GL_BUFFER_VARIABLE and
GL_ACTIVE_VARIABLES are answered by ProgramInterface.cpp out of a different index space),
so the two arms differ in exactly the two functions their callers use.
THE PULL BUILD KEEPS ALL OF IT, and the integrator should see why: the archive member is
MOBILEGL_BUILD_DISAGGREGATED-only because one more Vector in LinkArtifacts changes its
size, its implicit destructor and its move constructor, and G1 pins the pull build's .text
byte for byte. So §5.3's deletion is achieved in the disaggregated build and not in the
pull one; retiring the pull half is a one-line change the day that pin is retired or the
member moves. Filed as P13 in notes/p7/magma-c.md.
One improvement rides along: the monolith binding getter now asks the program for a
rebind on every read, over an immutable list, where it used to read a binding patched into
a mutable cache - so a rebind can no longer be lost to a cache rebuild that raced a
state-version bump.
G1: .text 0xa52203 unchanged, 27837 -> 27837 defined symbols, 0 added / 0 removed / 0
resized / 0 renamed, file byte-identical. An unguarded call site caught the guard rule
once mid-slice by failing the pull compile, which is the loud version.
RED-ONCE: publishing nothing reds the order-equivalence case (with the reference list
printed) and 25 of 60 storage-block scenarios - the MONOLITH DirectVulkan arm beside all
three transports, which is the evidence that the monolith consumer really was switched.
Restored: 61/61.
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.