swung0x48
8bb6309a1c
CONTRACT-P6.md 12.1 has carried "a ratchet recomputes the 184 in CI and asserts it only
ever falls" as an obligation since P6. The roadmap handed it to P6.5; the P6.5 line never
received it, and scripts/ci/ has never had anything that computes this number. ID-P7-7
gives it to P7 wave 0. This is it.
scripts/link_ratchet.py mechanises a6's hand experiment: partition the per-object output
of the single MobileGL target into SERVER / FRONTEND / SHARED, then compute
(SERVER undefined) - (SERVER defined) - (SHARED defined) intersect (FRONTEND defined),
which is the undefined-symbol list a real link of a server-only image would print. The
partition is an explicit table with a rationale per row, because it IS the module boundary
the build system does not have (SOURCE_FILES is one flat list; boundaries are P13's work).
An object matching no row is a hard failure, as is a build whose CMakeCache lacks the three
disaggregated options, or an empty role set - every way this gate could go green without
having measured anything is an explicit exit 2.
Measured on 78b7d6be: 186 symbols. The three backend buckets reproduce a6's hand-made
101 / 14 / 60 exactly, as do its per-object referrer and definer distributions
(UniformManager 90, VulkanRenderer 60, Managers 53, DirectGLES 51; TextureObject 59,
SamplerObject 30, BufferObject 18, FramebufferObject 16, PipeFill 9). Nothing from a6's
184 has been cleared; the +2 are both P6.5's:
Client::ClientSession::StartSpawned() - fork-per-session
GLState::ProgramArtifactsSchemaFingerprint() - archive v2 caps
The baseline stores the LIST, not a count (ID-P7-7): a count-only ratchet goes green on the
day one symbol is cleared and another added. --assert-monotone fails only on symbols absent
from the baseline and names each one's defining object and every referring object; symbols
that disappeared are reported with an instruction to re-baseline in the same commit, and
never fail.
The CI step goes in build-linux-split, not build-linux: build-linux takes the three options
from MOBILEGL_CI_DISAGGREGATED, which is ON only on feat/disaggregated and
codex/fix-github-ci, so on any other branch it builds a monolith and the gate would measure
a SERVER set with no transport half. The JSON is uploaded even when the gate fires.
Two findings for the integrator, both written up in the note:
- a6's four published bucket totals sum to 181 against its own headline of 184. These
buckets are a strict partition and always sum to the headline; the difference is in
a6's core bucket, which it listed selectively.
- 5 of the 14 "P3b/P4b" symbols are MG_Pipe slot-allocator and apply-thread plumbing
that sits under MG_Impl/Pipe/ by file location alone. P3b/P4b cannot clear them by
migrating Espryt functionality; they need P13's module move. That bucket's floor is
5, not 0, so the plan's 0.5-day Tier 1 estimate for "D12's 14 symbols" should be
re-cut against 9. All 7 symbols from that object carry a `# P13` annotation.
red-once (R-16) is recorded verbatim in the note. Worth knowing: the plan's own example
(SamplerObject::GetMinFilter) does NOT turn this gate red, because it is already in the
baseline - the ratchet reddens on new symbols, so a negative control has to pick one that
is not in the 186. A reach to GetBorderColorForm() from DirectGLES/Utils.cpp does, naming
the symbol, its definer and its referrer, exit 1; reverted and green again.
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.