swung0x48
c4be38005a
Two Iris cases died on the Redmi (Adreno 830v2, DirectVulkan inproc) with
Fatal{UnmigratedVerb, "Magma:mipmap-shader-format-or-shape"}, deterministically and
under both run-ahead and lockstep, while the monolith arm and the whole host lane
stayed green. That one line was the entire evidence, and five disjunctions share the
name, so the one thing the device could have told us - which format, at what shape,
missing which feature bit - was the one thing it did not.
The name stays first and unprefixed, because the census, the retrace refusal tally
and every log grep key on the leading word; the driver's own answer follows it:
format enum, the view's storage format when it reinterprets, extent, levels, aspect,
view type, usage bits, layer range, and the names of the optimalTilingFeatures bits
that are ABSENT. The next device run reads a line instead of re-deriving it.
The refusal also loses half its territory. The shader arm rendered STRAIGHT INTO the
next level, which needs the image to carry COLOR_ATTACHMENT usage - and a texture
whose format the device declines as a colour attachment never gets that bit, so every
sampled-only texture without BLIT support fell into the refusal rather than into a
fallback. When the FORMAT can be rendered and only the IMAGE cannot, an owned scratch
attachment of the destination level's size takes the pass and vkCmdCopyImage moves the
mip in: a raw texel move, no conversion, texels still from GPU contents rather than a
staged shadow, and the scratch retires with the submit that consumes it - the shape the
multisample resolve arm above it already uses.
Neither shader arm had ever executed on the gate machine. lavapipe reports
BLIT_SRC|BLIT_DST for every colour format this binary can create, so GenerateWireMipmap
takes its native arm for all of them; GenerateMipmapPackedFloatPixels next door looks
like it covers the shader arm and does not, because R11F_G11F_B10F blits natively here
too. MGITEST_MAGMA_FORCE_SHADER_MIPMAP drops the native arm instead, one tier per shape
(1 = render into the level, 2 = render into scratch and copy back), read once and
compiled only into the disaggregated build.
F1WireScenario.GenerateMipmapWithoutNativeBlitPixels paints two different halves rather
than one flat colour - a pass that loses GL's row order averages to the same number
everywhere, and a single-colour assertion would call that correct - and asserts level
one per half. It is registered on the three Magma arms twice, ONE ENVIRONMENT EACH: the
knob changes how every mipmap in the process is generated, so a lane-wide flip would
silently retarget the four green mipmap entries beside it.
Red once (executed, reverted): with the scratch arm forced off, the tier-2 entry dies
with Fatal{UnmigratedVerb, "Magma:mipmap-shader-format-or-shape format=37 extent=8x8x1
levels=4 aspect=0x1 view=1 usage=0x17 layers=0+1/1 missing=DEPTH_STENCIL_ATTACHMENT"},
by name and with the shape in it; restored, the same filter is 8/8 green.
Gates: integration-magma-split 75 (+2), -spawn 54 (+2), -tcp 56 (+2), 0 red;
ctest -L unit 2402/2402; informational integration-magma-full-split 511, 0 red, 58 skip
(the new case skips where the knob is unset); fatal_census green (79 abort sites, 43
family words, 0 unmarked - no site added, the funnel is unchanged); link_ratchet
--assert-monotone unchanged at 186, p7-magma bucket 101.
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.