BZLZHH
33e02f4bcf
- MGPipeSubDataWantsItsReply is the ONE place that decides whether a resource_subdata record waits
for its answer (WireTables.cpp:370 and PipeRoute.h:328 both read it, and the comment beside it
says that a second spelling is how the client comes to wait for an answer the emitter told the
server not to bother with). The buffer half has answered "no" since P5e; the texture half now
does too, ON THE WIRE ARM ONLY.
- THE ANSWER IS DERIVABLE THERE, which is the argument - not that nobody reads it:
* The emission is already gated on the answer's content. A texture record is produced only where
FamilyIsLive(kMGPipeSubsystemTextureResources, ...) holds, and under split that gate IS
CapsMirrorInstance().ServerConsumes(bit 10) (PipeFill.cpp:1719-1740) - the same published fact
the applier's own acceptance belt reads (PipeApply.cpp:1408-1419, NoP4aConsumer). So the one
refusal this acceptance exists to carry, "no consumer" (ID-39 / D-D5 / ID-18 M3, which is why
the texture half ever asked), cannot be the answer to a record this client emitted.
* What remains is a bug class, and it is loud already: a record that names no texture, declares
no texels or carries no bytes is an MGP_TRIP_WIRE_REPORT (PipeApply.cpp:1201-1218, :2245-2252),
and a handle the applier does not hold is counted and named (ResolveResourceIn, :721-728) with
the client's own tracker preventing it from arising (PipeFill.cpp:1045-1051).
* Every answer the client can still get for free, it still gets: the emitter reads this route's
Bool exactly as before, so a record the CLIENT cancelled (the device-lost latch, an exhausted
stage) still answers "not accepted" and the level stays dirty and is retried - D-D5's safe
direction, unchanged.
- THE WAIT MOVES TO THE STAGE. A run that does not fit SEG_STAGE reclaims retired bytes and parks
on the stage doorbell (PipeWireCodec.cpp StageAllocate / ReclaimStagedBytes) - the one wait a
run-ahead client owes, and it is proportional to the WINDOW rather than to the call count. On
Minecraft 26.2's atlas frame that is the handoff's 55,428 reply waits at ~4.4 ms each: 96 MiB of
uploads through a 32 MiB window.
- THE GATE IS THE NUMBER ITSELF. LinkMetricsReplyWaits is added so a case can read back the same
`wait_replies` the per-frame P65LinkMetrics line prints - LinkMetrics.cpp:76-80 counts exactly
the records that own a reply slot. TextureUploadsStopOwningAReplyOnTheWireArm asserts that a pure
glTexSubImage2D crosses the wire and moves it by ZERO, while a resource_create row - kWaitReply,
and it always was - still moves it, so the zero cannot be "nothing was counted". Red-once run:
with the arm test removed the child exits 142.
- Monolith and every non-wire arm are untouched, and that is pinned twice: the existing
RemoteRunAhead.OnlyTheTextureHalfOfResourceSubDataWantsItsReply still reads true with no arm
installed, and the new test sits inside MOBILEGL_BUILD_DISAGGREGATED with the original expression
as its fall-through, so a pull build preprocesses to the line it had (G1).
- Verification debt, stated rather than implied: the host gate is the COUNT, not a wall clock.
In-process control sessions run lockstep (the caps peer publishes no kCapRunAheadApply), so the
verb barrier still waits there; the end-to-end wall-clock win is the device measurement the
handoff describes and it has not been taken yet.
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.