What's New in WebGPU (Chrome 127)

François Beaufort
François Beaufort
GitHub

Experimental support for OpenGL ES on Android

You can now access a GPUAdapter from the OpenGL ES backend when requesting the experimental WebGPU compatibility mode in Chrome for Android. This is especially useful for Android devices lacking support for Vulkan 1.1 or greater. See the following example and issue dawn:1545.

// Request a GPUAdapter in compatibility mode
const adapter = await navigator.gpu.requestAdapter({ compatibilityMode: true });
WebGPU report page shows GPUAdapter info from the OpenGL ES backend on Android device.
OpenGL ES adapter info in webgpureport.org

As this feature is still in an experimental stage, you will need to perform the following steps:

  1. Enable the following Chrome flags: "Unsafe WebGPU Support", "WebGPU Developer Features", and "Enable command line on non-rooted devices".
  2. Enable USB Debugging on your Android Device.
  3. Connect your Android device to your workstation, run adb shell 'echo "_ --use-webgpu-adapter=opengles" > /data/local/tmp/chrome-command-line' to prefer the OpenGL ES backend over Vulkan, and restart Chrome.

GPUAdapter info attribute

Getting identifying information about an adapter can now be done in a synchronous way with the GPUAdapter info attribute. Previously, calling the asynchronous GPUAdapter requestAdapterInfo() method was the only way to get adapter info. However, requestAdapterInfo() has been removed from the WebGPU spec and will be removed in Chrome later this year to give enough time to web developers to make the necessary transition. See the following example, Chrome Status, and issue 335383516.

const adapter = await navigator.gpu.requestAdapter();
const info = adapter.info;

// During the transition period, you can use the following:
// const info = adapter.info || await adapter.requestAdapterInfo();

console.log(`Vendor: ${info.vendor}`); // "arm"
console.log(`Architecture: ${info.architecture}`); // "valhall"

WebAssembly interop improvements

To accommodate for WebAssembly heaps being passed directly to WebGPU, the sizes of the following BufferSource arguments are no longer restricted to 2 GB: dynamicOffsetsData in setBindGroup(), source data in writeBuffer(), and source data Pin writeTexture(). See issue 339049388.

Improved command encoder errors

Some validation errors raised from command encoders will now have improved contextual information. For example, attempting to start a compute pass while a render pass was still open resulted in the following error.

Command cannot be recorded while [CommandEncoder (unlabeled)] is locked and [RenderPassEncoder (unlabeled)] is currently open.
    at CheckCurrentEncoder (..\..\third_party\dawn\src\dawn\native\EncodingContext.h:106)

This does describe the reason for the error, however it doesn't indicate which call actually caused the validation error. The following error shows the improved messaging which includes the command that triggered the error. See change 192245.

Command cannot be recorded while [CommandEncoder (unlabeled)] is locked and [RenderPassEncoder (unlabeled)] is currently open.
 - While encoding [CommandEncoder (unlabeled)].BeginComputePass([ComputePassDescriptor]).

Dawn updates

The webgpu.h C API no longer exposes wgpuSurfaceGetPreferredFormat(), the C equivalent of Dawn's wgpu::Surface::GetPreferredFormat(). Instead, use wgpu::Surface::GetCapabilities() to get the list of supported formats, then use formats[0] to get the texture format preferred for this surface. In the meantime, calling wgpu::Surface::GetPreferredFormat() emits a deprecation warning. See issue 290.

The supported texture usages of a surface are now available through wgpu::SurfaceCapabilities::usages when calling wgpu::Surface::GetCapabilities(). They are expected to always include wgpu::TextureUsage::RenderAttachment. See issue 301.

This covers only some of the key highlights. Check out the exhaustive list of commits.

What's New in WebGPU

A list of everything that has been covered in the What's New in WebGPU series.

Chrome 127

Chrome 126

Chrome 125

Chrome 124

Chrome 123

Chrome 122

Chrome 121

Chrome 120

Chrome 119

Chrome 118

Chrome 117

Chrome 116

Chrome 115

Chrome 114

Chrome 113