swung0x48
df17c416c0
F1. `MG_State::Init()` runs before `MG_Backend::Init()`, and the second is what
starts the session - so `GLContext`'s `TextureState` constructor materialised its
eleven default texture objects, each of them emitted `resource_create` through
`FamilyIsLive`, and `CapsMirror::ServerConsumes(0x400)` answered every one of them
from a generation-0 placeholder with `callMask=0`. All eleven records were dropped
and the whole event was one WARN line:
MG_Remote client: the server does not consume MGPipe subsystem 0x400 - this
family emits NOTHING and the legacy pull path runs for it (R-8). callMask=0x0,
caps generation 0
It is NOT a race. The line reproduces byte-for-byte on lavapipe and on the Adreno
830, because the two Init calls are two statements on one thread. And "the legacy
pull path runs for it" is false on the client under split: there is no pull path
on this side of the wire, so withholding is not a fallback, it is a drop that only
a later respecify's self-healing create ever undoes.
Two of the three options the brief offered do not apply, and both facts are worth
recording. (b) "extend the P6.5 fix to inproc" is already the tree: `FinishStartup`
step 7 is the one funnel every transport reaches and it will not return without a
real snapshot. (a) "a bounded wait in Consumes()" cannot work alone and would
deadlock: at `MG_State::Init()` no handshake is in flight, and the one that will
land is started later BY THE SAME THREAD.
So the fix is the ORDER, with the rule behind it as the gate:
* `MobileGL::Initialize` calls `MG_Backend::InitSplitRolesBeforeState()` before
`MG_State::Init()`. `Init()`'s split arm becomes one body, `InitSplitBackend()`,
shared with the direct callers that still reach `Init()`; the monolith arm keeps
its place after `MG_State::Init()`, because moving it would move pull `.text`.
* `CapsMirror::ServerConsumes()` refuses to answer from a placeholder. It waits,
bounded, when a bring-up is genuinely in flight on ANOTHER thread, and otherwise
dies as `Fatal{CapsBeforeFirstSnapshot, "<family>"}` through `SessionFail` -
a new family word, one row in `FatalFamilies.def`, no new abort site.
* Two arms are exempt and say why in place: the server arm (`MGPipeServerArm()` -
the apply thread and the spawn server, where the client's mirror is the wrong
object rather than a late one), and a process whose own configuration never
asked for a split transport (`MG_Config::SplitTransportRequestedByConfig`, set
by `MG_ConfigLoader::InitTransport`, which is what tells a real run apart from a
fixture that assigns `MG_Config::Transport` by hand).
The read accessors keep P5's ruling untouched: `LogBackendInfo` reads
`GetRendererInfo()` during `MG_Backend::Init()` and an abort there is a process that
cannot start. Only the DECISION changed. The warning was not made quieter and the
callMask was not defaulted to all-ones.
`MOBILEGL_TEST_DELAY_FIRST_CAPS_MS` (server side, disaggregated builds, inert unless
set) holds back the FIRST CapsSnapshot. On spawn/tcp that is a genuinely late
snapshot in another process and it exercises the client's step-7 wait; on inproc it
only makes `Start` slower, which is itself the proof that the only window a client
can read a placeholder in is the one before `Start` is called.
G1: `.text` 0xa52203 and the 30570-symbol list identical to p7-before/pull-syms.txt.
Census: 79 abort sites unchanged, 44 family words (was 43). Link ratchet: 186,
unchanged.
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.