55a00c7a1f
This patch fixes an undefined behaviour on Metal and Vulkan when there is a color state whose corresponding fragment output is not declared in the fragment shader. According to Vulkan SPEC (Chapter 14.3), the input values to blending or color attachment writes are undefined for components which do not correspond to a fragment shader output. Vulkan validation layer follows the SPEC that it only allows the shader to not produce a matching output if the writemask is 0, or it will report a warning when the application is against this rule. When no fragment output matches the color state in a render pipeline, the output differs on different Metal devices. On some Metal devices the fragment output will be (0, 0, 0, 0) even if it is not declared in the shader, while on others there will be no fragment outputs and the content in the color attachments is not changed. This patch fixes this issue by setting the color write mask to 0 to prevent the undefined values being written into the color attachments. With this patch, the following end2end tests will not report warnings any more when we enable the Vulkan validation layer: ObjectCachingTest.RenderPipelineDeduplicationOnLayout/Vulkan ObjectCachingTest.RenderPipelineDeduplicationOnVertexModule/Vulkan ObjectCachingTest.RenderPipelineDeduplicationOnFragmentModule/Vulkan BUG=dawn:209 TEST=dawn_end2end_tests Change-Id: I5613daa1b9a45349ea1459fbdfe4a12d6149f0f7 Reviewed-on: https://dawn-review.googlesource.com/c/dawn/+/11581 Reviewed-by: Austin Eng <enga@chromium.org> Reviewed-by: Corentin Wallez <cwallez@chromium.org> Commit-Queue: Jiawei Shao <jiawei.shao@intel.com> |
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| build_overrides | ||
| docs | ||
| examples | ||
| generator | ||
| infra/config | ||
| scripts | ||
| src | ||
| third_party | ||
| .clang-format | ||
| .gitattributes | ||
| .gitignore | ||
| .gn | ||
| AUTHORS | ||
| BUILD.gn | ||
| CONTRIBUTING.md | ||
| DEPS | ||
| LICENSE | ||
| OWNERS | ||
| PRESUBMIT.py | ||
| README.chromium | ||
| README.md | ||
| codereview.settings | ||
| dawn.json | ||
| dawn_wire.json | ||
README.md
Dawn, a WebGPU implementation
Dawn (formerly NXT) is an open-source and cross-platform implementation of the work-in-progress WebGPU standard. It exposes a C/C++ API that maps almost one-to-one to the WebGPU IDL and can be managed as part of a larger system such as a Web browser.
Dawn provides several WebGPU building blocks:
- WebGPU C/C++ headers that applications and other building blocks use.
- A "native" implementation of WebGPU using platforms' GPU APIs:
- D3D12 on Windows 10
- Metal on OSX (and eventually iOS)
- Vulkan on Windows, Linux (eventually ChromeOS and Android too)
- OpenGL as best effort where available
- A client-server implementation of WebGPU for applications that are in a sandbox without access to native drivers
Directory structure
dawn.json: description of the API used to drive code generators.examples: examples showing how Dawn is used.generator: code generator for files produces fromdawn.jsontemplates: Jinja2 templates for the generator
scripts: scripts to support things like continuous testing, build files, etc.src:common: helper code shared between core Dawn libraries and tests/samplesdawn_native: native implementation of WebGPU, one subfolder per backenddawn_wire: client-server implementation of WebGPUinclude: public headers for Dawntests: internal Dawn testsend2end: WebGPU tests performing GPU operationsunittests: unittests and by extension tests not using the GPUvalidation: WebGPU validation tests not using the GPU (frontend tests)
utils: helper code to use Dawn used by tests and samples
third_party: directory where dependencies live as well as their buildfiles.
Building Dawn
Dawn uses the Chromium build system and dependency management so you need to install depot_tools and add it to the PATH.
On Linux you need to have the pkg-config command:
# Install pkg-config on Ubuntu
sudo apt-get install pkg-config
Then get the source as follows:
# Clone the repo as "dawn"
git clone https://dawn.googlesource.com/dawn dawn && cd dawn
# Bootstrap the gclient configuration
cp scripts/standalone.gclient .gclient
# Fetch external dependencies and toolchains with gclient
gclient sync
Then generate build files using gn args out/Debug or gn args out/Release.
A text editor will appear asking build options, the most common option is is_debug=true/false; otherwise gn args out/Release --list shows all the possible options.
Then use ninja -C out/Release to build dawn and for example ./out/Release/dawn_end2end_tests to run the tests.
Contributing
Please read and follow CONTRIBUTING.md. Dawn doesn't have a formal coding style yet, except what's defined by our clang format style. Overall try to use the same style and convention as code around your change.
If you find issues with Dawn, please feel free to report them on the bug tracker. For other discussions, please post to Dawn's mailing list.
License
Please see LICENSE.
Disclaimer
This is not an officially supported Google product.