swung0x48
bc6e24ff30
Three measured defects in the strict lane, one commit each in spirit and one in fact because
they are the same step.
1. THE LOG SET CAME FROM A DIRECTORY. The CI step grepped MG_IntegrationTest/split-logs/, which
holds 90 of the lane's entries. The ones it could not see were the F1. readback block, both
NamedBlit pairs, the four Ct. entries and PersistentMapArm - precisely the readback population
the allowlist is ABOUT, plus the only DirectVulkan entries in the lane. split_log_paths.py
gains a `markers` mode that walks ctest's own {entry: MOBILEGL_LOG_FILE_PATH} map and
classifies every Fatal{ and Admitted{ line. Measured on this head: 113 of 113 entries read.
The lane is now a TWO-SIDED RATCHET - an unadmitted marker fails, an admitted pair not in
Harness/strict-expected-markers.txt fails, AND an expected pair that no longer appears fails,
so the lane cannot rot green by outliving its own debts.
2. THE `rsp` CHECK GREPPED FOR A COUNTER NO SPLIT ENTRY EMITS, and the pin behind it was vacuous:
CountBarrierPull's unbarriered arm is [[noreturn]] and runs BEFORE ++g_residualPulls, so
"rsp = 0 on unbarriered records" was true of every possible implementation. Replaced by an
assertion where the counter actually is - one entry, DirectGLES.Split.StrictArming., with
MOBILEGL_PIPE_STATS=1, MOBILEGL_PIPE_STATS_PERIOD=1 and a private log path of its own (a
whole-lane env flip races under -j: the library opens that path "w"). It asserts
rsp == 0 || rsp >= draws, which is the device evidence's shape - rsp ~= the draw count under
inproc, 0 under monolith - so the draw path's retirement is visible as rsp ceasing to scale.
3. THE LANE HAD NO POSITIVE CONTROL (ID-115). Of the seven entries that passed strict, three were
monolith transport - where nothing stamps a verb boundary, so the whole mechanism is
structurally unreachable - two self-skipped, one was a death test and one was a Python check.
Not one was a record-carrying split GL scenario, so "green" and "strict was never armed" were
the same observation. New push-only counter `vbs` (PipeStats::ServerVerbBoundaries), counted
at MGPipeServerStampVerbBoundary behind Enabled(), and the same entry asserts vbs > 0 on a
frame that drew. It is deliberately NOT rsp: rsp reaches zero when the phase SUCCEEDS, so a
control built on it would start failing on the day the debt is paid.
- Measured on this head (base 7c6f6886, before pa and mv): isplit 119/119; under strict the
census is Fatal{ GetProgramForDraw@DrawArrays 52, GetBoundVertexArray@DrawArrays 9,
GetProgramForDispatch@DispatchCompute 7 - exactly what pa and mv owe - and Admitted{ on ten
pairs, three of them ADMITTED-ESCALATED. The expected-marker file carries all ten and says in
its header that the wave-3 merge retires three of them.
- CONTRACT-P5E §7 rewritten around what is now checkable: the derived allowlist and its three
disjuncts, the two-sided ratchet, the restated rsp pin, and the positive control.
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.