b749d07ac9
Enable the Vulkan backend when building Dawn with
the Chromium build system for Fuchsia. To make this
work properly the following is required:
- Modify VulkanInfo.cpp and BackendVk.cpp to correctly probe
the Fuchsia swapchain layer and its layer extension, as well
as enabling them when creating a new VkInstance.
- Modify VulkanFunctions.cpp to load the Fuchsia swapchain
related extension for this platform only.
- Provide a small mock GLFW library for Fuchsia under
src/utils/Glfw3Fuchsia.cpp, since the upstream project
does not support this platform at all. Its purpose is
only to allow the creation of the right VulkanBinding
instance, which depends on the creation of a display
surface for latter swapchain creation.
- Add //third_party/fuchsia-sdk:vulkan_base and
//third_party/fuchsia-sdk:vulkan_validation as
data_deps of the libdawn_native_sources target in
order to ensure that the Fuchsia package created by
the build system will include the correct Vulkan
libraries (loader and validation layers).
This builds correctly, and both dawn_unittests and
dawn_end2end_tests will run on a real Fuchsia device
or inside the Fuchsia emulator, using either GPU
virtualization or a software-based renderer.
Note: dawn_unittests will also run inside QEMU, but
not dawn_end2end_tests, since the latter requires
proper GPU emulation which is not available in this
environment.
NOTE: All end2end tests pass using a device with
an "Intel HD Graphics 615 (Kaby Lake GT2)"
adapter. However:
- For some reason, a single test takes up
to 129 seconds to pass
(BufferSetSubDataTests.ManySetSubData/Vulkan).
- The test process crashes inside VkDestroyInstance(),
apparently inside the Fuchsia-specific imagepipe
layer (which implements swapchain support).
This is likely a bug in the layer itself, and
not Dawn.
Also, may end2end tests will crash when run inside
the Fuchsia emulator (which uses GPU virtualization
to talk to the host GPU). The crashes happen inside
libvulkan-goldfish.so, the emulator-specific Vulkan
ICD on this sytem. Not a Dawn bug either.
Bug=dawn:221
Change-Id: Id3598b673e8c6393f24db728b8da49fdde3cac76
Reviewed-on: https://dawn-review.googlesource.com/c/dawn/+/8963
Commit-Queue: David Turner <digit@google.com>
Reviewed-by: Austin Eng <enga@chromium.org>
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.