Shaders: rust-gpu integration to compile shader nodes to WGSL (#3097)

* shaders: shader compilation setup

* nix: use rustc_codegen_spirv.so from nix

* shaders: codegen for per_pixel_adjust shader nodes

* shaders: disable nodes needing bool

* shaders: `#[repr(u32)]` some enums

* shaders: add lint ignores from rust-gpu

* shaders: fix node-macro tests

* gcore-shaders: toml cleanup

* shader-nodes feature: put rust-gpu to wgsl compile behind feature gate

* shaders: fix use TokenStream2

* shaders: allow providing shader externally

* Update iai runner in workflow

---------

Co-authored-by: Timon Schelling <me@timon.zip>
Co-authored-by: Dennis Kobert <dennis@kobert.dev>

node-graph/gcore-shaders/Cargo.toml

@@ -7,7 +7,23 @@ authors = ["Graphite Authors <contact@graphite.rs>"]
 license = "MIT OR Apache-2.0"
 
 [features]
-std = ["dep:dyn-any", "dep:serde", "dep:specta", "dep:log", "glam/debug-glam-assert", "glam/std", "glam/serde", "half/std", "half/serde", "num-traits/std"]
+# any feature that
+# * must be usable in shaders
+# * but requires std
+# * and should be on by default
+# should be in this list instead of `[workspace.dependency]`
+std = [
+	"dep:dyn-any",
+	"dep:serde",
+	"dep:specta",
+	"dep:log",
+	"glam/debug-glam-assert",
+	"glam/std",
+	"glam/serde",
+	"half/std",
+	"half/serde",
+	"num-traits/std"
+]
 
 [dependencies]
 # Local std dependencies

node-graph/gcore-shaders/src/color/color_types.rs

@@ -3,6 +3,7 @@ use super::discrete_srgb::{float_to_srgb_u8, srgb_u8_to_float};
 use bytemuck::{Pod, Zeroable};
 use core::fmt::Debug;
 use core::hash::Hash;
+use glam::Vec4;
 use half::f16;
 #[cfg(not(feature = "std"))]
 use num_traits::Euclid;
@@ -1075,6 +1076,21 @@ impl Color {
 			..*self
 		}
 	}
+
+	#[inline(always)]
+	pub const fn from_vec4(vec: Vec4) -> Self {
+		Self {
+			red: vec.x,
+			green: vec.y,
+			blue: vec.z,
+			alpha: vec.w,
+		}
+	}
+
+	#[inline(always)]
+	pub fn to_vec4(&self) -> Vec4 {
+		Vec4::new(self.red, self.green, self.blue, self.alpha)
+	}
 }
 
 #[cfg(test)]