Create shader from naga::Module

[wrnrlr]

I am looking into building a procedural macro in Rust that outputs a WSGL shader and was wondering how a naga::Module can be used directly instead of wgpu::ShaderSource. I found that in wgpu::Context::device_create_shader_module this is already being done based of a str through wgc::pipeline::ShaderModuleSource::Wgsl.

ShaderSource::Wgsl(ref code) => wgc::pipeline::ShaderModuleSource::Wgsl(Borrowed(code))

I was thinking of using naga::Module as the target of my shader transpiler instead of just concatenating strings with bits of WGSL.

Please tell me if this is not a good idea, and otherwise what the best way is to implement this feature?

[kvark]

I'm hesitating to make wgpu-rs accept a naga::Module because that would make naga a public dependency. Currently, it's a private dependency. So we can update naga without breaking the outside API.

Also, accepting naga::Module directly is not going to help the Web target, it will only be available on native.

Finally, Naga's IR is very close WGSL. Conversion to WGSL is very lightweight, and so is parsing WGSL. So you can just convert Naga IR to WGSL and pass it to us, portably.

[wrnrlr]

Thats sounds fair, I later relised that naga::Module probably doesn't belong in the Wgpu's public interface.
Can I still reuse the structs in naga::front::wgsl to represent the target AST of my transpiler, if so how can I turn this tree into a string, or do you thing it is better to write my own version of the wgsl grammar?

[kvark]

You can use Naga IR, and you'd use the WGSL backend to turn it into text for feeding into wgpu. See https://github.com/gfx-rs/naga/blob/cb0ad2504ce8bbd868237032f49c10c944b490cb/cli/src/main.rs#L413

[wrnrlr]

Thx, I'll do that