swung0x48
1255caa2fb
CONTRACT-P7 §5.4, OQ-10. InitServerRoleCommon computes the whole capability mask and
never ORed this bit, so MGPipeResourceOpsHaveSubDataResident answered false under every
transport and BOTH backends were pinned to the ordered in-place host memcpy - which made
Magma's SubDataResident arm (VkBufferManager.cpp's g_vulkanWireResourceOps) dead code on
the wire even though the arm has been there since P5f.
The bit is derived from g_resourceOpsAtStep2->SubDataResident, i.e. from the pointer this
function already pinned at step 2 and that step 5 already refuses to see swapped - never
from ActiveBackendType. That is ID-39's lesson and not a style preference: a mask is a
statement about THIS backend's registered table, and a bit derived from the enum would
keep claiming the capability for a build, a flavour or a future backend whose table does
not carry the arm.
`rsd=` joins the emit[] bracket on the PipeStats summary line, counted at the emitter once
per buffer_subdata_resident record rather than once per call, because a write past the
content chunk cap is cut into several records. It is the only observable that separates
the resident arm from the memcpy beside it: the bytes in the buffer are identical either
way, which is exactly how the capability stayed unpublished for a phase with every lane
green.
WHAT THIS DOES NOT YET PROVE, and R-6 is the reason rather than an omission. §5.4 asks for
a white-box case showing opcode 49 on the wire. None can exist at this tree: the resident
arm is reached only from a GPU-RESIDENT store, residency comes only from
AdoptPersistentMap, and every persistent-map acquisition declines under split by R-6
(PipeApply.cpp:2331 "A SPLIT BUILD RUNS AT TIER T2 AND DECLINES EVERY ACQUISITION,
ALWAYS"; T0/T1 are P11's and AdoptTierIsEmulate is a named Fatal for them). So the
capability is wired AHEAD of its consumer, deliberately, and `rsd=` is what will show the
records the day P11 lands a tier that adopts. Filed for the integrator in
notes/p7/magma-c.md.
What IS proved is both halves of the bit itself. RemoteClientTest's Magma bootstrap case
now asserts the published bit EQUALS `ops->SubDataResident != nullptr` - the two compared
to each other rather than both to true, so the case also covers a backend without the arm
on the day one exists - and a new CtWireScenario case reads the bit out of the client's
own caps mirror, through the same accessor the frontend reads, on both backends and all
three transports.
RED-ONCE, both levels. Deleting the OR reds
CapsMirrorTest.MagmaTransportPublishesRealBufferConsumersWithoutRunAhead
(RemoteClientTest.cpp:692, "Which is: false / Which is: true") and all SIX arms of
DirectGLES/DirectVulkan x {Split,Spawn,Tcp} Ct.TheServerPublishesTheResidentSubData
CapabilityFromItsOwnTable ("the client's caps mirror did not receive
kCapResidentSubData"). Restored: green.
Also carries the P4a death-helper comment from the previous commit's sweep: it no longer
says Magma installs no death table, because it now does and still frees no slot.
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.