An earlier CL [1] enabled Vulkan validation layers on Linux which also enables validation layers on Chrome OS. Unfortunately, this changes breaks the Chrome OS build of Dawn: .../vulkan.h:63:10: fatal error: 'xcb/xcb.h' file not found This is because including the validation layers also includes the Vulkan-Headers repo which has a BUILD file that defines VK_USE_PLATFORM_XCB_KHR [2]. XCB (and all of X11, for that matter) is not supported on Chrome OS even though it is a Linux platform. This is a quick fix for the problem to unbreak the BUILD, but I think we should discuss what a long-term fix looks like. Do we send a patch to Khronos to add an "is_chromeos" branch to their BUILD file a la Fuchsia? Also, as mentioned by cwallez@ in a different CL of mine, we should really set up a Chrome OS trybot to catch these earlier. I can assign a bug to myself for that! [1] https://dawn-review.googlesource.com/c/dawn/+/13787 [2] https://github.com/KhronosGroup/Vulkan-Headers/blob/master/BUILD.gn#L23 Change-Id: Ic5fb4fa7990cc2232a7416145877e24b10a2a7b6 Reviewed-on: https://dawn-review.googlesource.com/c/dawn/+/13880 Reviewed-by: Austin Eng <enga@chromium.org> Commit-Queue: Brian Ho <hob@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.
- The main C header for the WebGPU API.
- Definition of a structure of all function pointers for this specific Dawn version (called "proctable").
- A C++ wrapper for the C header.
- 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, Android and Fuchsia 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
- A Dawn proc-table backend implementation of WebGPU for applications what want to be able to switch at runtime between native or client-server mode.
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.json
templates
: 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.