do color mapping per-pixel

src/lib.rs

@@ -401,7 +401,7 @@ impl Core {
 								incident: Ray::new(pos, dir),
 								normal,
 							});
-							let color = colormap(light);
+							let color = Vec3::splat(light);
 							render::faces::Vertex { pos, color }
 						})
 						.collect::<Vec<_>>(),

src/render/colormap.wgsl

@@ -0,0 +1,32 @@
+struct LookParams {
+	m: mat4x4f,
+}
+
+struct Vertex {
+	@location(0) pos: vec3f,
+	@location(1) color: vec3f,
+}
+
+struct Varying {
+	@builtin(position) screen: vec4f,
+	@location(0) color: vec4f,
+}
+
+@group(0) @binding(0) var<uniform> look: LookParams;
+
+fn colormap(light: f32) -> vec3f {
+	let brightness = 3. * (1. - 1. / (1. + light));
+	return vec3(brightness, brightness - 1., brightness - 2.);
+}
+
+@vertex
+fn on_vertex(in: Vertex) -> Varying {
+	let pos = look.m * vec4f(in.pos, 1.0);
+	let color = vec4f(in.color, 1.0);
+	return Varying(pos, color);
+}
+
+@fragment
+fn on_fragment(in: Varying) -> @location(0) vec4f {
+	return vec4f(colormap(in.color.x), 1.0);
+}

src/render/faces.rs

@@ -79,7 +79,7 @@ impl Pipeline {
 
 		let shader = device.create_shader_module(wgpu::ShaderModuleDescriptor {
 			label: None,
-			source: wgpu::ShaderSource::Wgsl(super::SIMPLE_SHADER.into()),
+			source: wgpu::ShaderSource::Wgsl(super::COLORMAP_SHADER.into()),
 		});
 		let pipeline = device.create_render_pipeline(&wgpu::RenderPipelineDescriptor {
 			label: None,

src/render/mod.rs

@@ -2,6 +2,7 @@ pub mod faces;
 pub mod lines;
 
 static SIMPLE_SHADER: &str = include_str!("simple.wgsl");
+static COLORMAP_SHADER: &str = include_str!("colormap.wgsl");
 
 pub const OUTPUT_FORMAT: wgpu::TextureFormat = wgpu::TextureFormat::Bgra8UnormSrgb;
 pub const DEPTH_FORMAT: wgpu::TextureFormat = wgpu::TextureFormat::Depth24Plus;