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P3b/P4b wave 2-D package D3, slice 1. The defect package D2 found with its new
TextureViewAliasScenario gate and excluded by name because the fix is outside D2's footprint.
THE HOLE. Once a glTextureView had been SAMPLED, a later glTexSubImage through the OWNER's
own name never became visible through the view, on inproc, spawn and tcp, green under
monolith. The client half was never at fault: the case's own emit-counter assertions pass on
the red run, so the records were emitted and the applier accepted them. A view owns no texels
and the client keeps ONE emission cursor per storage - an upload through a view's name is
remapped onto its storage owner before it is emitted (MG_Impl/Pipe/TextureEmit.h) - so every
resource_subdata for either name is keyed on the OWNER and ApplyTextureUpload moves the
OWNER's Serial and PendingUploads alone. BackendTextureObject::IsDrawSyncCleanByRecord read
the VIEW's Serial and PendingUploads, which nothing an upload does can move, so the gate
answered CLEAN for every owner write after the view's first sample and the sync that would
have drained the owner's pending uploads never ran.
THE FIX, AND WHY THIS ONE. The gate's two STORAGE clauses are asked of the STORAGE record -
this record for a texture that owns its texels, the record Desc.ViewOf names for a view -
through the new PipeTextureStorageRecordForRecord. The three PARAMETER clauses stay the
view's own record's, because a view has its own texture parameters and its own built-in
sampler, which is the whole reason the second name exists. SyncTextureViewToBackendByRecord
stamps that same storage serial at both its arms, so the stamp and the gate name one
quantity. This is the split equivalent of the monolith gate's GetContentVersion(), which
TextureObjectView forwards to its owner (TextureObjectView.cpp:100-102).
THE ALTERNATIVE WAS REJECTED. A reverse index owner->views, so an owner-side resource_subdata
bumps every viewing record's Serial, is the other shape D2 named. It is wrong here on three
counts: it puts new mutable state in MG_Pipe's applier, which both backends read, to answer a
question one backend's gate asks; it makes ApplyTextureUpload write a record other than the
one the call names, which breaks the applier's own serial discipline; and its index has to be
pruned on view death or an owner upload bumps a recycled slot's Serial - a silent
cross-texture hazard with no test that would catch it. The resolve direction needs no state,
no pruning, and is checked at every use: PipeTextureRecordForHandle tests Live and Gen.
DELETION ORDERING, WHICH DECIDED IT. A view holds a STRONG SharedPtr to its storage owner
(TextureObjectView::m_storageOwner) and the client emits resource_destroy from the DESTRUCTOR,
not from glDeleteTextures - "the last SharedPtr to this object dropping, not the glDelete*
that only marks the name and leaves a still-bound object very much alive"
(TextureObject.cpp:63). So an owner's record outlives every record that views it whatever
order the application deletes the two names in, and the forward edge cannot dangle. The walk
checks anyway, and a null answer is NOT clean - the direction that re-syncs.
VIEWS OF VIEWS. ONE hop always reaches storage: glTextureView composes a view-of-a-view onto
the ROOT at creation (the spec's additive min-level rule), the client's emitter says so and
TextureObjectView's invariant is that its owner is never a view. The walk is transitive
anyway and BOUNDED at four hops, because this side may not depend on a client invariant to
terminate; a cyclic chain the wire could forge ends as a null answer, which is "not clean",
not a refusal. No new abort site and no new Fatal (rule I): fatal_census abort_sites stays 79.
RED-ONCE (rule J), the case D2 excluded, with the exclusion lifted and nothing else changed,
at D2's head a7c06f4f:
ctest -R 'DirectGLES\.(Split|Spawn|Tcp)\.TextureViewAliasScenario' -j 3
-> 79% tests passed, 3 tests failed out of 14
4042 - DirectGLES.Split.TextureViewAliasScenario.TheOwnerUploadDrainRunsAgainAfterADrawBoundary (Failed)
4046 - DirectGLES.Spawn.TextureViewAliasScenario.TheOwnerUploadDrainRunsAgainAfterADrawBoundary (Failed)
4050 - DirectGLES.Tcp.TextureViewAliasScenario.TheOwnerUploadDrainRunsAgainAfterADrawBoundary (Failed)
the first owner write, through the view: 11408 of 11408 pixels disagree;
first at (2, 2) is rgba(50,160,30,255), expected rgba(0,0,255,255) +/- 2
the second owner write, through the view: 11408 of 11408 pixels disagree;
first at (2, 2) is rgba(50,160,30,255), expected rgba(255,255,0,255) +/- 2
Only the PIXEL channel is red; the drain's emit counters pass, which is what places the
defect on the server. The monolith control DirectGLES.TextureViewAliasScenario.* is 4/4 in
the same run. With the fix: 14/14, 100%.
CONTRACT-P5E.md 5.2's clean gate is amended to state the rule the code now implements, and
says out loud that the rec->Serial form it carried through P5e was wrong rather than
restating it. The CMake exclusion is lifted; the scenario registers all four cases on all
three arms again (G14: the name never left any lane).
G1: .text 0xa52203, nm --defined-only 30570 symbols, 0 added / 0 removed, -D 0/0. Every line
touched in Managers.cpp is inside #if MOBILEGL_PIPE_PUSH (the gate and the resolver) or
#if MOBILEGL_BUILD_DISAGGREGATED (the view sync), and Managers.h's declaration is inside the
PIPE_PUSH block, so the pull build's preprocessed text is 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.