src/fill.wgsl

@@ -12,11 +12,11 @@ fn on_vertex(@builtin(vertex_index) vi: u32) -> Varying {
 }
 
 @fragment
-fn on_fragment(in: Varying) -> @location(0) vec4u {
+fn on_fragment(in: Varying) -> @location(0) u32 {
 	let x = bitcast<u32>(in.screen.x);
 	let y = bitcast<u32>(in.screen.y);
 	let rand = hash(hash(hash(SEED) ^ hash(x)) ^ hash(y));
-	return vec4(rand >> 31, rand >> 30, rand >> 29, rand >> 28) & vec4(1u);
+	return rand >> 31;
 }
 
 fn hash(key : u32) -> u32 {

src/main.rs

@@ -47,7 +47,7 @@ fn main() {
 			entry_point: None,
 			compilation_options: wgpu::PipelineCompilationOptions::default(),
 			targets: &[Some(wgpu::ColorTargetState {
-				format: wgpu::TextureFormat::Rgba8Uint,
+				format: wgpu::TextureFormat::R8Uint,
 				blend: None,
 				write_mask: wgpu::ColorWrites::ALL,
 			})],
@@ -80,7 +80,7 @@ fn main() {
 			entry_point: None,
 			compilation_options: wgpu::PipelineCompilationOptions::default(),
 			targets: &[Some(wgpu::ColorTargetState {
-				format: wgpu::TextureFormat::Rgba8Uint,
+				format: wgpu::TextureFormat::R8Uint,
 				blend: None,
 				write_mask: wgpu::ColorWrites::ALL,
 			})],
@@ -122,6 +122,17 @@ fn main() {
 		cache: None,
 	});
 
+	let state_sampler = device.create_sampler(&wgpu::SamplerDescriptor {
+		label: None,
+		address_mode_u: wgpu::AddressMode::Repeat,
+		address_mode_v: wgpu::AddressMode::Repeat,
+		address_mode_w: wgpu::AddressMode::Repeat,
+		mag_filter: wgpu::FilterMode::Nearest,
+		min_filter: wgpu::FilterMode::Nearest,
+		mipmap_filter: wgpu::FilterMode::Nearest,
+		..Default::default()
+	});
+
 	let mut state = None;
 	#[allow(deprecated)]
 	event_loop
@@ -155,7 +166,7 @@ fn main() {
 								mip_level_count: 1,
 								sample_count: 1,
 								dimension: wgpu::TextureDimension::D2,
-								format: wgpu::TextureFormat::Rgba8Uint,
+								format: wgpu::TextureFormat::R8Uint,
 								usage: wgpu::TextureUsages::RENDER_ATTACHMENT | wgpu::TextureUsages::TEXTURE_BINDING,
 								view_formats: &[],
 							})
@@ -242,10 +253,16 @@ fn main() {
 						&device.create_bind_group(&wgpu::BindGroupDescriptor {
 							label: None,
 							layout: &step_pipeline.get_bind_group_layout(0),
-							entries: &[wgpu::BindGroupEntry {
+							entries: &[
+								wgpu::BindGroupEntry {
 									binding: 0,
 									resource: wgpu::BindingResource::TextureView(&state.last),
-							}],
+								},
+								wgpu::BindGroupEntry {
+									binding: 1,
+									resource: wgpu::BindingResource::Sampler(&state_sampler),
+								},
+							],
 						}),
 						&[],
 					);

src/present.wgsl

@@ -15,6 +15,6 @@ fn on_vertex(@builtin(vertex_index) vi: u32) -> Varying {
 @fragment
 fn on_fragment(in: Varying) -> @location(0) vec4f {
 	let pos = vec2u(in.screen.xy);
-	let state = textureLoad(field, pos, 0).xy;
-	return vec4(vec2f(state), 0., 1.);
+	let state = textureLoad(field, pos, 0).x;
+	return vec4f(f32(state));
 }

src/step.wgsl

@@ -12,50 +12,19 @@ fn on_vertex(@builtin(vertex_index) vi: u32) -> Varying {
 }
 
 @group(0) @binding(0) var field: texture_2d<u32>;
+@group(0) @binding(1) var smp: sampler;
 
 @fragment
-fn on_fragment(in: Varying) -> @location(0) vec4u {
-	let dim = vec2i(textureDimensions(field));
-	let center = vec2i(in.screen.xy);
-	var nb: array<array<vec4u, 3>, 3>;
-	for (var j = 0; j < 3; j++) {
-		for (var i = 0; i < 3; i++) {
-			let off = vec2i(i, j);
-			let coords = (center + off + dim - 1) % dim;
-			let px = textureLoad(field, coords, 0);
-			nb[j][i] = px;
-		}
-	}
-	let state = nb[1][1];
-	var n = vec4u();
-	for (var j = 0; j < 3; j++) {
-		for (var i = 0; i < 3; i++) {
-			n += nb[i][j];
-		}
-	}
-	n -= state;
-
-	let z = daynight(state.z, n.z);
-	let x = life(state.x, n.x + n.z);
-	let y = life(state.y, n.y + 8u - n.x);
-	return vec4(x, y, z, 0u);
-}
-
-fn life(state: u32, n: u32) -> u32{
+fn on_fragment(in: Varying) -> @location(0) u32 {
+	let a = textureGather(0, field, smp, in.uv, vec2(0, 0));
+	let b = textureGather(0, field, smp, in.uv, vec2(0, 1));
+	let c = textureGather(0, field, smp, in.uv, vec2(1, 0));
+	let d = textureGather(0, field, smp, in.uv, vec2(1, 1));
+	let state = a.y;
+	let n = a.x + a.z + a.w + b.x + b.y + c.y + c.z + d.y;
 	switch (n) {
 	case 2u: { return state; }
 	case 3u: { return 1u; }
 	default: { return 0u; }
 	}
 }
-
-fn daynight(state: u32, n: u32) -> u32{
-	switch (n) {
-	case 3u: { return 1u; }
-	case 4u: { return state; }
-	case 6u: { return 1u; }
-	case 7u: { return 1u; }
-	case 8u: { return 1u; }
-	default: { return 0u; }
-	}
-}