Rendering to OffscreenCanvas on non-yielding workers

[awtcode]

Hi,

I currently execute my code in a Web Worker and does not yield the context back to the browser because everything happens in a while loop. As such, I need to pass the OffScreen Canvas back to the main thread for rendering.

Here are my questions:

1. Will WebGPU support the OffScreenCanvas API?
2. Can we have an API to support rendering from a Worker even if the context is not yielded back to the Worker?

[kainino0x]

1. Yes, you will be able to use it similarly to WebGL with transferControlToOffscreen (though WebGPU's exact presentation API may change between now and then).
2. I think we will be able to support this. It's not entirely solved yet. WebGL OffscreenCanvas commit() was rejected as a web platform feature, but we continue to keep this use case in mind as it is critical for ports of native code to WebAssembly.

[awtcode]

Thanks for the prompt reply @kainino0x :) It will be great if we can have (2) because I am currently working on porting AutoCAD to Wasm and being able to render directly from the Worker without having to transfer control back to the main thread would be a huge plus.

[awtcode]

@kainino0x and @Kangz , can I check if OffScreenCanvas is currently available for WebGPU in Chrome Canary on Windows now? If not, is there an estimate on when it will be ready? Thanks.

[Kangz]

@awtcode I don't think any of the WebGPU implementations have OffscreenCanvas right now. In Chromium it is blocked on some internal code refactor so it won't be available at least until the end of the year, maybe more.

[awtcode]

Thanks for your reply @Kangz .

[stefan-pdx]

Hi @kainino0x -- do you happen to know the status of the internal refactor? I'm really looking forward to accessing WebGPU from Web Workers.

Thanks!

[Kangz]

@s11k It's still ongoing (but had recent progress). You can follow along this Chromium bug.

[Kangz]

FYI offscreen canvas is completely working in WebGPU in Chromium now. Closing now since this was more of a question on WebGPU than a spec discussion.