Re: WebGPU on the Raspberry Pi 4

Hey Doug,

Just to add to what Dzmitry said from the Dawn/NXT side of things. We
support some non-conformant form of WebGPU on OpenGL 4.5 at the moment and
have ideas of how that could be extended to OpenGL ES 3.1 with more
restrictions. That said it's not in our medium-term priorities at this time
because we are first trying to make WebGPU work on first-class targets.
Support for OpenGL ES 3.1 will require both an implementation of a backend
for Dawn (esp. wgpu) and then integration in Chromium (resp. Firefox), both
of which are large chunks of work.

Chromium will have support for running WebGPU with Swiftshader (a Vulkan
software rasterizer) eventually so that might be another path if you're
mostly interested in trying the API. Swiftshader doesn't support ARM64 yet
though.

Cheers,

Corentin

On Sun, Dec 22, 2019 at 2:02 AM Dzmitry Malyshau <dmalyshau@mozilla.com>
wrote:

> Hi Doug,
>
> We've been discussing the possibility of defining a reduced WebGPU spec
> targeting OpenGL ES and D3D11 (distantly similar to how Vulkan Portability
> is a reduced spec of Vulkan). There is strong desire from both Mozilla and
> Google to make it work on OpenGL ES, at least, given that there is a lot of
> platforms still (especially in Android space) that don't have
> Vulkan/Metal/D3D12. So far, the working group hasn't agreed on how the spec
> will be extended/"subtended" for OpenGL ES, and it's not the goal of the
> whole group. We may end up with a reduced profile specified outside of the
> group.
>
> In terms of implementation, Google's NXT prototype had OpenGL support from
> the start.
>
> "gfx-rs" does have an OpenGL ES backend that is very rough (not production
> ready) but we are serious about getting it work, in particular by looking
> for a GSoC student to help with this. "wgpu" used to support OpenGL, and
> that was cut out, hopefully temporarily. There is a high chance Firefox
> will be able to run *some* WebGPU applications on OpenGL ES 3.1 in the
> future, but we have more important work right now than chasing this.
>
>
> Hope this is helpful.
>
> Regards,
>
> Dzmitry
> On 12/21/19 5:45 PM, Doug Moen wrote:
>
> I wonder if there is hope for WebGPU in a web browser running on the
> Raspberry Pi 4?
>
> There is no Vulkan driver available, nor is there OpenGL. Instead, there
> is an OpenGL ES 3.1 driver (compute shaders) in the final stages of
> development, and work has begun to support OpenGL ES 3.2 (geometry
> shaders). So my question is whether OpenGL ES 3.1/3.2 is good enough to
> support WebGPU?
>
>
> https://www.raspberrypi.org/blog/vc4-and-v3d-opengl-drivers-for-raspberry-pi-an-update/
>
> Mozilla's gfx-rs/wgpu project says nothing about OpenGL ES 3.1 support. I
> do see some kind of OpenGL support in the underlying gfx-hal library, but
> nothing is being promised for wgpu. So maybe there will be no Firefox
> support.
>
> Google's Dawn project says "OpenGL as best effort where available". There
> is no mention of version numbers, though. Will Dawn support OpenGL ES
> 3.1/3.2?
>
>
>