runs on any GPU – even in the browser
Seems pretty clickbaity and dishonest when that's just what webgl and webgpu means. Just say webgpu.
Also the roughness doesn't apply to the environment map.
I think you're getting lost in the weeds there. I do not see malice in the claim.
The irony is that it does not actually run on my GPU, nor much of other people's, judging by the comments. I don't know where people get this idea that WASM and WebGPU are the holy grail of portability; they are the opposite and the whole ecosystem is a fucking disaster. No offense to OP, though; I can understand the temptation to target that platform.
Anyway, I left more positive feedback in another comment.
If you click into the code you can see that it depends on `wgpu`, which is a wrapper that uses whichever native API would be appropriate for the platform you're working with. If you run the native compiled version you won't be using WebGPU.