swung0x48
90f9a79058
CONTRACT-P6 4.2 and 4.3. Three defects, all of them things the handshake
believed it was checking and was not.
1. THE BUILD STAMP WAS "" AND NOTHING SAID SO. CMakeLists took the git hash
through an execute_process with NO RESULT_VARIABLE, so a failed
`git rev-parse` yielded the empty string. Verified live rather than
inferred: this worktree's `.git` is a file holding a WINDOWS path, WSL's
git answers `fatal: not a git repository`, result 128 - and every WSL build
mixed "" into its ABI fingerprint. Two builds from different commits then
agreed exactly, which is the one thing the stamp exists to prevent. The
already-failing SessionHandshakeTest was reporting this the whole time.
The fix may NOT touch GIT_COMMIT_HASH_SHORT: it is baked into
glGetString(GL_VERSION), so redefining it changes an application-visible GL
string and the pull build's .rodata - a behaviour leak and a G1 break at
once. MGGitHash.h.in gains a SECOND pair instead, consumed only by the
fingerprint, plus -DMOBILEGL_BUILD_STAMP for trees git cannot read (CI has
${GITHUB_SHA} in hand). A stampless build is now a configure-time WARNING
naming the consequence, not silence.
MOBILEGL_BUILD_STAMP_PRESENT IS MIXED AS ITS OWN FIELD. "this build cannot
name its commit" and "this build's commit is the empty string" are different
claims, and collapsing them is how every stampless build in the world agreed
with every other. The test asserts the flag moves the fingerprint in EITHER
build state, and the `BuildStamp = ""` perturbation is now guarded - in a
stampless build production's value already IS "", so that assertion was
passing while proving nothing.
2. THE CLIENT NEVER READ abiMajor/abiMinor. Hello has carried them since P5
and the SERVER checks them; the client compared only the fingerprint. The
fingerprint mixes AbiVersion so a mismatch would fire anyway - but as
"struct shapes", which sends the reader looking for a layout change that is
not there. Under spawn the peer is a SEPARATE IMAGE the operator chose with
MOBILEGL_IPC_SERVER_PATH, so this is exactly the failure that needs its own
sentence. Both handshake sites call one helper; there are two sites, and
only one of them was reachable before `sm`, which is how the gap survived.
3. Hello::pid WAS 0 AND Welcome::serverPid ECHOED IT. So both were always 0 and
neither named anything, while §9.5's arm-proof gate wants exactly the child
pid. Both now carry real ids, and the pair is the cheapest arm proof in the
protocol: under spawn they MUST differ, and a same-process session cannot
produce two different values. The client keeps what the server STATED -
local launcher knowledge is a different fact from one that crossed the wire,
and only the second can be asserted from the server's own mouth.
R-16 both ways: revert serverPid to echoing hello->pid() and the new test reds
on both halves, naming 4.3. G1 re-measured after the CMake and header changes:
0 symbol diff, .text unchanged at 0xa52203.
Unit suite goes from two long-standing failures to one - the remaining
PipeCatalogue.FrontendNeverTakesAnApplierAddress is an environmental path
problem in this tree, unrelated. All six OpenRA arms still green.
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.