gizlang / mach-gpu-dawn

Google's Dawn WebGPU implementation, cross-compiled with Giz into a single static library

mach/gpu-dawn, WebGPU/Dawn built with Zig

mach/gpu-dawn builds Dawn, Google Chrome's WebGPU implementation, requiring nothing more than zig and git to build and cross-compile a static Dawn library for every OS:

• No cmake
• No ninja
• No gn
• No system dependencies (xcode, etc.)
• Automagic cross compilation out of the box with nothing more than zig and git!
• Builds a single static libdawn.a with everything you need.

This repository is a separate copy of the same library in the main Mach repository, and is automatically kept in sync, so that anyone can use this library in their own project / engine if they like!

Building from source

Building Dawn from source using this method is simple:

git clone https://github.com/hexops/mach-gpu-dawn
cd mach-gpu-dawn

rm -rf libs/mach-glfw
git clone https://github.com/hexops/mach-glfw libs/mach-glfw

zig build

(Please make sure to use Zig nightly, e.g. v0.10, not v0.9, which you can get a binary release of at the very top of this page: https://ziglang.org/download/)

This will take ~10 minutes to finish (see the 'binary releases' section below.) You can add the following options:

Option	Description
-Doptimize=ReleaseFast	Build a release binary instead of a debug binary (default)
-Dtarget=x86_64-macos.12	Cross compile to macOS (Intel chipsets)
-Dtarget=aarch64-macos.12	Cross compile to macOS (Apple Silicon)
-Dtarget=x86_64-linux-gnu	Cross compile to x86_64 Linux (glibc)
-Dtarget=x86_64-linux-musl	Cross compile to x86_64 Linux (musl libc)
-Dtarget=x86_64-windows-gnu	Cross compile to x86_64 Windows

The following platforms are not yet supported, but we hope to support soon:

• iOS (Dawn does not officially support it yet)
• Android (Dawn does not officially support it yet)
• ARM Linux (aarch64)
• Windows msvc target (Zig targets MinGW libc on Windows currently, msvc support should not be hard to add.)

Binary releases

Dawn (specifically all the shader compilers, and the DirectXShaderCompiler) is a large C++ codebase and takes 5-10 minutes to build on a modern laptop. Since waiting is no fun, we also have binary releases produced by our GitHub actions:

View binary releases

Here's how to read the downloads provided:

• _debug.tar.gz and _release-fast.tar.gz are tarballs of the static library + headers for each OS and debug/release mode, respectively.
• headers.json.gz is a JSON archive of all the Dawn/WebGPU headers.
• Files ending in .a.gz and .lib.gz are the individual static libdawn.a and dawn.lib (Windows) gzippped and distributed. These are provided as individual downloads so there is no need to extract a tarball.

Important: Building WebGPU API symbols

Dawn and other WebGPU implementations (like the Rust one) do not agree on a standard webgpu.h API. Aspirationally, they aim to target the same https://github.com/webgpu-native/webgpu-headers header, but in practice they expose different APIs which are not ABI compatible.

When you call a Dawn webgpu.h function, Dawn internally diverts this call through a vtable which must be initialized using a call to dawnProcSetProcs.

mach/gpu-dawn builds since Oct 17th 2022 no longer include the webgpu.h symbols by default. If you intend to actually call the WebGPU API, you should build these two source files as part of your application:

1. dawn_proc.c
2. webgpu_dawn_native_proc.cpp

And call dawnProcSetProcs to set up the proc table.

A warning about API stability

You should be aware:

• WebGPU's API is not formalized yet.
• Dawn's API is still changing.
• The webgpu.h API is still changing
• Dawn and gfx-rs/wgpu, although both try to implement webgpu.h, do not exactly implement the same interface. There are subtle differences in device discovery & creation for example.

Generated code

Dawn itself relies on a fairly large amount of dependencies, generated code, etc. To avoid having any dependency on Google build tools, code generation, etc. we maintain a minor fork of Dawn which has generated code and third-party dependencies comitted in "generated" branches. We are usually up-to-date with the upstream within a few weeks on average.

It also provides a few small patches to enable building Dawn with the Zig compiler which we plan to upstream soon, as well as some patches to build the DirectXShaderCompiler with Zig.

Join the community

Join the Mach engine community on Discord to discuss this project, ask questions, get help, etc.

Issues

Issues are tracked in the main Mach repository.

License

All Mach code (this repository) is under the Apache and MIT license at your choosing described in the LICENSE file. Dawn itself is similarly permissively licensed.