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- A window with no Present divided by a faked 1 and printed the window TOTALS under
"bytes/f[...]": the *MultiDraw* slice (47 draws, no present) reported 1,404,550 bytes as a
PER-FRAME figure, a 47x overstatement of exactly the SEG_STAGE sizing input plan B section
8.2 / section 11 P0 asks this package to produce. FormatWindowLine now relabels the bracket
to "bytes[...]" and prints draws/f=n/a when the window holds no frame; acc/draw=n/a follows
the same rule, because "0.00" beside a non-zero acc= is the same lie. Pinned by
PipeStatsTest.SummaryLineSurvivesZeroFrames and the reworked SummaryLineSurvivesZeroDraws.
- Every per-frame and per-draw field now goes through one FormatFixed2 helper. draws/f read 1
for 26 draws over 14 frames (1.86) and buf read 97 for 1360 bytes (97.14): a systematic
downward truncation of up to a whole unit on the figures the package exists to produce.
Pinned by PipeStatsTest.PerFrameFieldsKeepTwoDecimals.
- FormatSummaryLine rewrote the window bases as a side effect of formatting, so any second
reader silently zeroed the next window. Split into a pure FormatWindowLine() and an explicit
AdvanceSummaryWindow(); EmitSummaryLine calls both. Pinned by
PipeStatsTest.FormattingTwiceDoesNotConsumeTheWindow.
- Init() called ResetForTesting(), against the header's own "not used by any shipping path".
Both now forward to an internal ResetCounters().
- TracyPlot published only the MISS half of each gate under the gate's unqualified name, so
the headline output channel of section 11 P0 carried no denominator. Two series per gate now
("...-hit" / "...-miss") from static literal arrays. The payload histogram stays unplotted
and says why: it is a run-total distribution over draws (section 4.5.7), not a per-frame
scalar, and it reaches the operator through the JSON dump.
- GetOrCreatePipeline's 15-call tally sat ABOVE the list-topology primitive-restart refusal,
so a declined draw added ten reads it never made - an OVER-count, which breaks the lower
bound contract every other tally keeps. Moved to immediately before the payload build, and
the enumeration reconciled with the constant: the excluded read is the sample-shading
capability, short-circuited by m_sampleRateShadingFeatureEnabled.
- Six real staging paths were uncounted while the inventory claimed coverage. The inventory
claim "DirectVulkan's own buffer staging ... has no second copy to count" was simply false.
Now wired: MultiDraw.cpp's UploadScratch/UploadScratchRing (indirect commands, the compute
tier's draw-info array, the rebased index stream - the class is passed in, so a new tier
cannot forget it); Managers.cpp's pool-recycle reseed and the VBO-backed Float64 narrowing;
VkBufferManager's eight host->device copies of buffer contents plus UploadTransient, the
single chokepoint for Magma's per-draw vertex/index/indirect staging; VkTextureManager's
packed staging slice, with the same box/rect SHAPE split Espryt already reported.
- New byte class stage-indirect-cmd, for draw PARAMETER bytes a backend synthesises and
stages. Kept out of stage-index-client because these are the population that becomes MGPipe
command-record payload (section 4.5.7), not resource bytes. A name addition, not a rename:
no recorded baseline is invalidated.
- stage-ubo-named moved past the zero-copy direct-bind decision in ResolveUniformBufferPayload
(a direct bind repacks nothing, so counting it there reported a copy that never happened),
and Magma's default-uniform-block image now feeds stage-ubo-global the way Espryt's does,
counted after the per-frame slice memo.
- The site inventory in PipeStats.cpp is rewritten to name every unwired path by file and
function. An inventory that overstates coverage is worse than a missing counter, because
the zero is then read as an answer.
- Evidence, lavapipe/llvmpipe, MOBILEGL_PIPE_STATS=1: the MultiDraw slice now prints
"window=0 draws/f=n/a bytes[buf=1404550 ...]"; the indirect tiers
(MOBILEGL_ESPRYT_MULTIDRAW_MODE=indirect|multiindirect) move icmd 0 -> 660; Magma's GuiBatch
line moves from buf=0 tex=0 ubog=0 to buf=685.71 tex=41.14 ubog=157.71 with tex[emit=9
box=9 rect=0 jobs=9]. Off-path A/B against the base tree with the env unset, 9 runs each of
a 40-scenario draw slice, sorted totals in ms: Espryt base 389..794 (median 399) vs branch
384..403 (median 394); Magma base 406..472 (median 410) vs branch 408..761 (median 414) -
the always-compiled guard is below this harness's noise on both backends.
- 1410 unit tests green (15 PipeStatsTest). integration-gpu 860/860, 860/860, 859/860; the one
failure is DirectVulkan.PointSizeDemotion...TheDemotionIsActuallyArmedWhenTheEnvironmentPins-
ItOn, a member of the load-dependent *IsActuallyArmed* flake family already present in the
untouched base tree, and it passes 8/8 standalone here. stdio gate and gen_pipe check green.
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.