Expose shader source

[stefnotch]

I needed access to the shader source so that I could create the shader module with a custom label.

And I also wanted access to the source so that I can patch shader functions on the fly.

[ScanMountGoat]

I needed access to the shader source so that I could create the shader module with a custom label.

I've found adding a label to just the pipeline to be sufficient for my debugging. If you think setting the module label would be helpful, you could add a separate function that takes a label to the generated code. It should also be possible to just write your own function and avoid using wgsl_to_wgpu for creating the module itself.

And I also wanted access to the source so that I can patch shader functions on the fly.

If you're modifying the shader source at build time, you can just modify the source before passing it to wgsl_to_wgpu. If you need to modify the source at runtime, there's no longer any guarantee that the bindings generated by wgsl_to_wgpu are correct.

[stefnotch]

I'm using this for an app that's compiled to WASM, so there's always a bit of "keeping the binary size down". If I use wgsl_to_wgpu, but then need to separately inject the shaders into the binary, then I believe I'd end up with two copies of the shaders.

If you need to modify the source at runtime, there's no longer any guarantee that the bindings generated by wgsl_to_wgpu are correct

There are two cases where currently I do that. One is purely for debug purposes, so it's fine if the guarantees are broken. And the other one is constrained to be "replace a single function's body", which we need for swapping out the underlying "parametric function that maps a 2D value to a 3D coordinate". Demo

Another case is for swapping out const values in a WGSL shaders in places where pipeline-overridable constants cannot be used, due to WGSL restrictions. Examples

I would be more than happy to expose the source as something that's clearly marked as "the user is responsible for the guarantees" or unsafe.

[ScanMountGoat]

That makes sense. Does it cover your use cases to just make the shader source public like in this PR?

[stefnotch]

Yes, that fully covers my use-cases.

[stefnotch]

Thank you! Also thank you for maintaining this excellent library!

On a completely different note: Once a WGSL imports project like naga_oil or WESL improves, I'll let you know and hopefully contribute a PR. One that keeps full compatibility with WGSL as-is, and optionally lets users do a bit more.