Shaders: add BufferStruct to support bool and enums

[Firestar99]

Requires #2985

• Adds the trait BufferStruct
• support for
  • gamma_correction
  • channel_mixer
  • selective_color
  • brightness_contrast_classic
    • The original brightness_contrast node doesn't work with it's non-classic mode. However, we now have a "Brightness Contrast Classic" CPU node next to the "Brightness Contrast" and "Brightness Contrast Classic GPU" nodes.

BufferStruct docs

/// A BufferStruct is a "parallel representation" of the original struct with some fundamental types remapped. This /// struct hierarchy represents how data is stored in GPU Buffers, where all types must be [`Pod`] to allow /// transmuting them to `&[u8]` with [`bytemuck`]. /// /// Notable type remappings (original: buffer): /// * bool: u32 of 0 or 1 /// * any repr(u32) enum: u32 with remapping via [`num_enum`] /// /// By adding `#[derive(ShaderStruct)]` to your struct (or enum), a parallel `{name}Buffer` struct is created with all /// the members of the original struct, but with their types using the associated remapped types as specified by this /// trait. /// /// # Origin /// I (@firestar99) copied this entire mod from my [Nanite-at-home] project, specifically the [buffer-content] crate /// and the [buffer_struct] proc macro. The variant here has quite some modifications, to both cleaned up some of the /// mistakes my implementation has and to customize it a bit for graphite. /// /// Hopefully rust-gpu improves to the point where this remapping becomes unnecessary. /// /// [Nanite-at-home]: https://github.com/Firestar99/nanite-at-home /// [buffer-content]: https://github.com/Firestar99/nanite-at-home/tree/008dac8df656959c71efeddd2d3ddabcb801771c/rust-gpu-bindless/crates/buffer-content /// [buffer_struct]: https://github.com/Firestar99/nanite-at-home/blob/008dac8df656959c71efeddd2d3ddabcb801771c/rust-gpu-bindless/crates/macros/src/buffer_struct.rs /// /// # Safety /// The associated type Transfer must be the same on all targets. Writing followed by reading back a value must result /// in the same value. 

[TrueDoctor]

Could we use a proper doc link which allows you to click on the BufferStruct here?

[Firestar99]

oh yea with a dev-dependency... I hope the link I made is correct, rustrover isn't linking this

[Firestar99]

Added one more commit to fix shader name naming