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- New CMake option MOBILEGL_BUILD_DISAGGREGATED (default OFF, plan B appendix B). ON appends the MG_Remote sources to SOURCE_FILES, puts 3rdparty/flatbuffers/include on the include path and defines MOBILEGL_BUILD_DISAGGREGATED=1. OFF compiles nothing from MG_Remote and adds no include path and no library, which is one of the two byte-level equalities plan B section 10.3 keeps: measured `nm --defined-only build-linux/libMobileGL.so | grep -ic MG_Remote` = 0 with the option OFF and 93 with it ON, with an identical ldd set in both configurations.
- The option forces itself OFF with message(WARNING) when 3rdparty/flatbuffers/include/flatbuffers/flatbuffers.h is missing, so a checkout without the submodule still configures and builds rather than failing a hundred lines later on a missing header.
- ITransport.h: SendFrame / ReceiveFrame / PeekFrameSize / ShareFd / ReceiveFd / Shutdown. ReceiveFrame's contract is the fix for a defect of the earlier branch: a destination buffer smaller than the pending message returns MOBILEGL_ERR_BUFFER_TOO_SMALL with the required size and KEEPS the message queued. The earlier transport failed the call and popped the message anyway, which wedges the stream permanently the first time a reader guesses a size wrong.
- Framing.h: [u32 'MGLF'][u32 len][payload], 64 MiB cap, validated on read. A bad magic or an oversized length latches the reader dead, is logged at ERROR and makes every later call return MOBILEGL_ERR_PROTOCOL_MISMATCH. This is the second inherited defect: Feat/CS-Delta-IPC's Framing.h:41-45 Feed() always returned OK and its header peek merely returned false, so a desynchronized stream became a silent permanent hang; its LocalSocketTransport.cpp:232-236 then allocated on the peer-supplied length with no cap. The magic is also byte-ordered so it reads "MGLF" on the wire, where the earlier constant spelled "FLGM".
- Ring.h/.cpp: RingControl exactly as the inherited design (plan B section 8.1 -> earlier section 6.2): two independent cursor triples (cmd and stage, each {head, appliedTail, retiredTail}), appliedSeq / submittedSeq / retiredSeq / completedFrameSerial / presentAckSerial, serverEpoch, ringGeneration, consumerParked, producerParked, eventRingFull, eventDropped. One 4096-byte page with each contended group on its own cache line, pinned by static_assert on size and alignment and by an offset test.
- The SPSC pair uses monotonic byte cursors and a power-of-two mask, so a torn read can never look like a valid earlier position. A record never straddles the wrap: the producer emits a kPad filler to the boundary, which is always a multiple of 8 and therefore always has room for a header. The producer reclaims against retiredTail rather than appliedTail, so the day the server borrows a ring slot into the GPU timeline (kRecBorrowSlot) it does not silently degrade to early recycling. HardDrainRing bumps ringGeneration only when the ring is quiesced, and leaves the cursors monotonic so cached offsets are recognisably stale.
- The consumer bounds-checks every record header before dispatch (8-aligned, at least a header, no larger than what the producer published, contiguous inside the mapping) and reports corruption to the caller instead of dispatching into undefined behaviour. That is the runtime half of the earlier section 6.3 discipline: SEG_CMD is written by another process, so a compile-time static_assert on record sizes proves nothing about what is in the mapping.
- Doorbell.h/.cpp: spin then park, both directions (earlier section 6.2a). CondVarDoorbell for inproc, SocketDoorbell for spawn (one byte, codes 0x01 ring-advanced and 0x02 watermark-advanced) - no futex, eventfd or named event anywhere. The lost-wakeup window is closed by ordering: the waiter stores its park flag seq_cst and then re-tests the condition, NotifyIfParked loads the same flag seq_cst after the watermark is published, so one of the two always sees the other. kDefaultSpinUs is 50, the MOBILEGL_IPC_SPIN_US default.
- ShmSegment.{h,cpp} + ShmSegmentPosix.cpp: memfd_create by raw syscall on desktop Linux (the glibc wrapper is too recent to rely on), ASharedMemory_create on Android (API 26; libc's memfd_create wrapper is API 30, above MobileGL's floor), shm_open + immediate shm_unlink as the fallback. Adopt() refuses a descriptor whose fstat size is smaller than the size the peer announced, so a short segment cannot turn every later offset into an out-of-bounds map. ShmSegmentWin32.cpp (CreateFileMappingW in Local\) is compile-guarded and untested - this project's Windows machine is not a correctness gate.
- The Android path is compile-verified, not just written: an arm64-v8a NDK build with the option ON links, ShmSegmentPosix.cpp.o carries an undefined ASharedMemory_create, and ShmSegmentWin32.cpp.o is empty there. That build is also what caught the missing <cstddef> in ShmSegment.h and Framing.h, where std::size_t / std::ptrdiff_t only resolved through a transitive include on the host sysroot.
- FdPassing.{h,cpp}: SCM_RIGHTS in the FIRST transport commit, as plan B section 8.1 demands, over a dedicated AF_UNIX SOCK_DGRAM socketpair rather than the control byte stream (message boundaries survive on every POSIX - SOCK_SEQPACKET does not exist on macOS - and ancillary data can never be split from its payload). The third inherited defect this replaces: Feat/CS-Delta-IPC deferred fd passing and hardcoded `out->fd = -1` in LocalSocketTransport.cpp:296, so on the only platform that matters its data plane could not move one byte between processes. MSG_CTRUNC, an unexpected descriptor count and a malformed sideband header all close every descriptor received before failing, and a too-small sideband buffer is refused before the recvmsg so a datagram is never half-consumed.
- InProcessTransport.{h,cpp}: two in-memory queues plus the condvar doorbell pair. It keeps the frame size cap so nothing that passes in inproc becomes illegal after the switch to spawn, hands descriptors over with dup() under the same ownership rule as SCM_RIGHTS, and lets a peer's queued messages be drained after Shutdown - usually the last one says why it is going away.
- Not done here on purpose: the MOBILEGL_IPC_* environment variables are parsed in ConfigLoader.cpp, which belongs to another P0 work package running in parallel; this commit only exposes the constants (kDefaultSpinUs, kMaxFramePayloadSize, FdPassing::kMaxSidebandBytes) so that plumbing has something to set.
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.