Fix issues

src/pipelines/agents/agent-pipeline.ts

@@ -1,4 +1,4 @@
-import { AGENT_SIZE, Agent } from './agent';
+import { AGENT_SIZE_IN_BYTES, Agent } from './agent';
 import shader from './agent.wgsl';
 
 export class AgentPipeline {
@@ -8,11 +8,16 @@ export class AgentPipeline {
   private readonly pipeline: GPUComputePipeline;
   private readonly uniforms: GPUBuffer;
   private readonly agentsBuffer: GPUBuffer;
+
   private bindGroup?: GPUBindGroup;
   private previousTrailMapIn?: GPUTexture;
   private previousTrailMapOut?: GPUTexture;
 
   public constructor(private readonly device: GPUDevice, agents: Array<Agent>) {
+    if (agents.length === 0) {
+      throw new Error('No agents provided');
+    }
+
     this.pipeline = device.createComputePipeline({
       layout: 'auto',
       compute: {
@@ -29,16 +34,16 @@ export class AgentPipeline {
     });
 
     const serializedAgents = new Float32Array(
-      new ArrayBuffer(agents.length * AGENT_SIZE)
+      new ArrayBuffer(agents.length * AGENT_SIZE_IN_BYTES)
     );
-    agents.forEach((agent, index) => {
-      serializedAgents[index * 4 + 0] = agent.position[0];
-      serializedAgents[index * 4 + 1] = agent.position[1];
-      serializedAgents[index * 4 + 2] = agent.angle;
+    agents.forEach((agent, i) => {
+      serializedAgents[i * 4 + 0] = agent.position[0];
+      serializedAgents[i * 4 + 1] = agent.position[1];
+      serializedAgents[i * 4 + 2] = agent.angle;
     });
 
     this.agentsBuffer = device.createBuffer({
-      size: agents.length * AGENT_SIZE,
+      size: agents.length * AGENT_SIZE_IN_BYTES,
       usage: GPUBufferUsage.STORAGE | GPUBufferUsage.COPY_SRC | GPUBufferUsage.COPY_DST,
     });
 
@@ -97,7 +102,9 @@ export class AgentPipeline {
     passEncoder.setPipeline(this.pipeline);
     passEncoder.setBindGroup(0, this.bindGroup);
     passEncoder.dispatchWorkgroups(
-      Math.ceil(this.agentsBuffer.size / AGENT_SIZE / AgentPipeline.WORKGROUP_SIZE)
+      Math.ceil(
+        this.agentsBuffer.size / AGENT_SIZE_IN_BYTES / AgentPipeline.WORKGROUP_SIZE
+      )
     );
     passEncoder.end();
   }

src/pipelines/agents/agent.ts

@@ -5,4 +5,4 @@ export interface Agent {
   angle: number;
 }
 
-export const AGENT_SIZE = 4;
+export const AGENT_SIZE_IN_BYTES = 4 * 4;

src/pipelines/agents/agent.wgsl

@@ -18,7 +18,7 @@ struct Settings {
 };
 
 @group(0) @binding(0) var<uniform> settings : Settings;
-@group(0) @binding(1) var<storage, read_write> agents: array<Agent>;
+@group(0) @binding(1) var<storage, read_write> agents : array<Agent>;
 @group(0) @binding(2) var TrailMapIn : texture_2d<f32>;
 @group(0) @binding(3) var TrailMapOut : texture_storage_2d<rgba16float, write>;
 
@@ -46,8 +46,6 @@ fn main(@builtin(global_invocation_id) global_id : vec3<u32>) {
 
   var agent = agents[id];
 
-
-
   var random = f32(hash(
     u32(
       agent.position.y * f32(settings.width) + agent.position.x

src/pipelines/diffusion/diffuse.wgsl

@@ -1,34 +1,28 @@
-struct VertexOutput {
-  @builtin(position) Position : vec4<f32>,
-  @location(0) fragUV : vec2<f32>,
-}
-
-@vertex
-fn vertex(@builtin(vertex_index) i : u32) -> VertexOutput {
-  var pos = array<vec2<f32>, 4>(
-    vec2(-1.0, 1.0),
-    vec2(-1.0, -1.0),
-    vec2(1.0, 1.0),
-    vec2(1.0, -1.0),
-  );
-
-  var output : VertexOutput;
-  output.Position = vec4<f32>(pos[i], 0.0, 1.0);
-  output.fragUV = output.Position.xy * 0.5 + 0.5;
-  return output;
-}
-
-
-@group(0) @binding(0) var mySampler: sampler;
-@group(0) @binding(1) var TargetTexture : texture_2d<f32>;
+struct Settings {
+  size : vec2<f32>,
+  diffusionRate : f32,
+  decayRate : f32,
+  deltaTime : f32,
+};
 
+@group(0) @binding(0) var<uniform> settings : Settings;
+@group(0) @binding(1) var Sampler: sampler;
+@group(0) @binding(2) var trailMap : texture_2d<f32>;
 
 @fragment
-fn fragment(@location(0) fragUV: vec2<f32>) -> @location(0) vec4<f32> {
-  // return vec4(1.0, 0.0, 0.0, 1.0);
-  return mix(
-    vec4(textureSample(TargetTexture, mySampler, fragUV).rgb, 0.1),
-    vec4(1.0, 1.0, 1.0, 1.0), 
-    0.01
+fn fragment(@location(0) uv: vec2<f32>) -> @location(0) vec4<f32> {
+  let current = textureSample(trailMap, Sampler, uv).rgb;
+
+  let neighbours: vec3<f32> = (
+      textureSample(trailMap, Sampler, uv + vec2<f32>(0, 1) / settings.size).rgb
+    + textureSample(trailMap, Sampler, uv + vec2<f32>(0, -1) / settings.size).rgb
+    + textureSample(trailMap, Sampler, uv + vec2<f32>(-1, 0) / settings.size).rgb
+    + textureSample(trailMap, Sampler, uv + vec2<f32>(1, 0) / settings.size).rgb
   );
+
+  return vec4(mix(
+    current,
+    neighbours / 4.0,
+    settings.diffusionRate
+  ) * (1.0 - settings.decayRate), 1.0);
 }

src/pipelines/diffusion/diffusion-pipeline.ts

@@ -1,19 +1,23 @@
+import { setUpFullScreenQuad } from '../../utils/full-screen-quad';
 import shader from './diffuse.wgsl';
 
 export class DiffusionPipeline {
+  private static readonly UNIFORM_COUNT = 6;
+
   private readonly pipeline: GPURenderPipeline;
+  private readonly uniforms: GPUBuffer;
+  private readonly quadVertexBuffer: GPUBuffer;
+
   private bindGroup?: GPUBindGroup;
   private previousTrailMapIn?: GPUTexture;
 
   public constructor(private readonly device: GPUDevice) {
+    const { buffer, vertex } = setUpFullScreenQuad(device);
+    this.quadVertexBuffer = buffer;
+
     this.pipeline = device.createRenderPipeline({
       layout: 'auto',
-      vertex: {
-        module: device.createShaderModule({
-          code: shader,
-        }),
-        entryPoint: 'vertex',
-      },
+      vertex,
       fragment: {
         module: device.createShaderModule({
           code: shader,
@@ -29,6 +33,31 @@ export class DiffusionPipeline {
         topology: 'triangle-strip',
       },
     });
+
+    this.uniforms = this.device.createBuffer({
+      size: DiffusionPipeline.UNIFORM_COUNT * Float32Array.BYTES_PER_ELEMENT,
+      usage: GPUBufferUsage.UNIFORM | GPUBufferUsage.COPY_DST,
+    });
+  }
+
+  public setParameters({
+    width,
+    height,
+    diffusionRate,
+    decayRate,
+    deltaTime,
+  }: {
+    width: number;
+    height: number;
+    diffusionRate: number;
+    decayRate: number;
+    deltaTime: number;
+  }) {
+    this.device.queue.writeBuffer(
+      this.uniforms,
+      0,
+      new Float32Array([width, height, diffusionRate, decayRate, deltaTime])
+    );
   }
 
   public execute(
@@ -49,11 +78,12 @@ export class DiffusionPipeline {
       ],
     };
 
-    const renderPassEncoder = commandEncoder.beginRenderPass(renderPassDescriptor);
-    renderPassEncoder.setBindGroup(0, this.bindGroup!);
-    renderPassEncoder.setPipeline(this.pipeline);
-    renderPassEncoder.draw(4, 1);
-    renderPassEncoder.end();
+    const passEncoder = commandEncoder.beginRenderPass(renderPassDescriptor);
+    passEncoder.setPipeline(this.pipeline);
+    passEncoder.setVertexBuffer(0, this.quadVertexBuffer);
+    passEncoder.setBindGroup(0, this.bindGroup);
+    passEncoder.draw(4, 1);
+    passEncoder.end();
   }
 
   private ensureBindGroupExists(trailMapIn: GPUTexture) {
@@ -63,13 +93,19 @@ export class DiffusionPipeline {
         entries: [
           {
             binding: 0,
+            resource: {
+              buffer: this.uniforms,
+            },
+          },
+          {
+            binding: 1,
             resource: this.device.createSampler({
               magFilter: 'linear',
               minFilter: 'linear',
             }),
           },
           {
-            binding: 1,
+            binding: 2,
             resource: trailMapIn.createView(),
           },
         ],

src/pipelines/render/render-pipeline.ts

@@ -1,7 +1,10 @@
+import { setUpFullScreenQuad } from '../../utils/full-screen-quad';
 import shader from './render.wgsl';
 
 export class RenderPipeline {
   private readonly pipeline: GPURenderPipeline;
+  private readonly quadVertexBuffer: GPUBuffer;
+
   private bindGroup?: GPUBindGroup;
   private previousColorTexture?: GPUTexture;
 
@@ -10,14 +13,12 @@ export class RenderPipeline {
     private readonly device: GPUDevice,
     preferredCanvasFormat: GPUTextureFormat
   ) {
+    const { buffer, vertex } = setUpFullScreenQuad(device);
+    this.quadVertexBuffer = buffer;
+
     this.pipeline = device.createRenderPipeline({
       layout: 'auto',
-      vertex: {
-        module: device.createShaderModule({
-          code: shader,
-        }),
-        entryPoint: 'vertex',
-      },
+      vertex,
       fragment: {
         module: device.createShaderModule({
           code: shader,
@@ -42,17 +43,18 @@ export class RenderPipeline {
       colorAttachments: [
         {
           view: this.context.getCurrentTexture().createView(),
-          clearValue: { r: 0.0, g: 0.0, b: 0.0, a: 1.0 },
+          clearValue: { r: 1.0, g: 1.0, b: 1.0, a: 1.0 },
           loadOp: 'clear',
           storeOp: 'store',
         },
       ],
     };
-    const renderPassEncoder = commandEncoder.beginRenderPass(renderPassDescriptor);
-    renderPassEncoder.setBindGroup(0, this.bindGroup);
-    renderPassEncoder.setPipeline(this.pipeline);
-    renderPassEncoder.draw(4, 1);
-    renderPassEncoder.end();
+    const passEncoder = commandEncoder.beginRenderPass(renderPassDescriptor);
+    passEncoder.setPipeline(this.pipeline);
+    passEncoder.setVertexBuffer(0, this.quadVertexBuffer);
+    passEncoder.setBindGroup(0, this.bindGroup);
+    passEncoder.draw(4, 1);
+    passEncoder.end();
   }
 
   private ensureBindGroupExists(colorTexture: GPUTexture) {

src/pipelines/render/render.wgsl

@@ -1,30 +1,8 @@
-struct VertexOutput {
-  @builtin(position) Position : vec4<f32>,
-  @location(0) fragUV : vec2<f32>,
-}
-
-@vertex
-fn vertex(@builtin(vertex_index) i : u32) -> VertexOutput {
-  var pos = array<vec2<f32>, 4>(
-    vec2(-1.0, 1.0),
-    vec2(-1.0, -1.0),
-    vec2(1.0, 1.0),
-    vec2(1.0, -1.0),
-  );
-
-  var output : VertexOutput;
-  output.Position = vec4<f32>(pos[i], 0.0, 1.0);
-  output.fragUV = output.Position.xy * 0.5 + 0.5;
-  return output;
-}
-
-
 @group(0) @binding(0) var mySampler: sampler;
 @group(0) @binding(1) var TargetTexture : texture_2d<f32>;
 
 
 @fragment
-fn fragment(@location(0) fragUV: vec2<f32>) -> @location(0) vec4<f32> {
-//   return vec4(1.0, 0.0, 0.0, 1.0);
-  return textureSample(TargetTexture, mySampler, fragUV);
+fn fragment(@location(0) uv: vec2<f32>) -> @location(0) vec4<f32> {
+  return textureSample(TargetTexture, mySampler, uv) * 10.0;
 }