Port some glsl shaders over to wgsl

[josephreisinger]

This PR ports over a number of glsl shaders over to wgsl for usage in webgpu projects.

As wgsl does not support function definition overloading with different parameter type signatures, the naming convention roughly follows the practice of including a number after each function name to indicate the major parameter's dimension (e.g. func1 for f32 vars and func3 for vec3f). Note that this may be controversial, e.g. in cases like exposure3.

Formatting is using wgsl-analyzer.

A few important notes:

1. The lack of preprocessor #defines in wgsl means that we can no longer use define guards to ensure against circular dependencies or re-importing the same header. Combined with wgsl's lack of overloading (noted above) I ended up having to patch webpack-glsl-loader (see fork here: https://github.com/josephreisinger/webpack-glsl-loader). This works for my particular case, but obviously is not helpful for folks who don't use webpack. Not sure what the best approach would be for this more generally / flagging for @patriciogonzalezvivo
2. All these functions are have been tested in situ using the eyeball metric, but I haven't made any attempts to verify precision or otherwise test numerically.
3. Generally I have avoided making changes to existing files, except in a few small cases where necessary.

Please let me know if you have any feedback or if there is anything I can do to make this easier to review. Happy to split it up functionally or otherwise if that is better for you?

[patriciogonzalezvivo]

Thank you @josephreisinger! great contribution! Wellcome permanently to the https://lygia.xyz/license as a contributor : )
I was wonder if you don't mind creating a README_WGSL.md with your translation notes + @sdedovic notes. He also did some translations and arrive to similar solutions. There is also this issue thread about WGSL constrains you will find interesting. Would be great if they can also hear you voice and wishes

[josephreisinger]

Awesome! Yep will do. Great to see some motion on the wesl standard also!

[josephreisinger]

Also I'm curious have you looked at Naga as a way to potentially automatically convert glsl->wgsl?

[sdedovic]

Hey I'm a little late to the party. This looks awesome.

@josephreisinger In my initial attempts with Naga, I found it made the code quite unreadable and decided against it. I figure for something like this library, the ability to read and understand the code was important. I tried to keep variable names consistent between WGSL and the reference implementations in GLSL / HLSL. AFAIK, Naga renames variables. So I opted to do it mostly manually.