perlin

src/pipelines/diffusion/diffuse.wgsl

@@ -12,10 +12,12 @@ struct Settings {
 @group(0) @binding(0) var<uniform> settings: Settings;
 @group(0) @binding(1) var Sampler: sampler;
 @group(0) @binding(2) var trailMap: texture_2d<f32>;
+@group(0) @binding(3) var noise: texture_2d<f32>;
 
 @fragment
 fn fragment(@location(0) uv: vec2<f32>) -> @location(0) vec4<f32> {
   var current = textureSample(trailMap, Sampler, uv);
+  let noise = textureSample(noise, Sampler, uv);
 
   let neighbours: vec4<f32> = (
       textureSample(trailMap, Sampler, uv + vec2<f32>(0, 1) / settings.size)
@@ -27,14 +29,15 @@ fn fragment(@location(0) uv: vec2<f32>) -> @location(0) vec4<f32> {
   let mixedTrails = mix(
     current.rgb,
     neighbours.rgb,
-    settings.diffusionRateTrails
+    settings.diffusionRateTrails + (noise.rgb - vec3(0.5)) * 0.1
   ) * (1.0 - settings.decayRateTrails);
 
   let mixedBrush = mix(
     current.a,
     neighbours.a,
-    settings.diffusionRateBrush
-  ) * (1.0 - settings.decayRateBrush);
+    settings.diffusionRateBrush + (noise.a - 0.5) * 0.5
+  ) * (1.0 - settings.decayRateBrush  - (noise.a - 0.5) * 0.1);
+
 
   return clamp(vec4(mixedTrails, mixedBrush), vec4(0), vec4(1));
 }

src/pipelines/diffusion/diffusion-pipeline.ts

@@ -1,4 +1,5 @@
 import { setUpFullScreenQuad } from '../../utils/graphics/full-screen-quad/full-screen-quad';
+import { generateNoise } from '../../utils/graphics/noise/noise';
 import { smartCompile } from '../../utils/smart-compile';
 import { CommonParameters } from '../common-parameters';
 import shader from './diffuse.wgsl';
@@ -10,11 +11,22 @@ export class DiffusionPipeline {
   private readonly pipeline: GPURenderPipeline;
   private readonly uniforms: GPUBuffer;
   private readonly quadVertexBuffer: GPUBuffer;
+  private readonly noise: GPUTexture;
 
   private bindGroup?: GPUBindGroup;
   private previousTrailMapIn?: GPUTexture;
 
   public constructor(private readonly device: GPUDevice) {
+    this.noise = generateNoise({
+      device,
+      width: 256,
+      height: 256,
+      octaves: 8,
+      amplitude: 0.12,
+      gain: 0.7,
+      lacunarity: 80,
+    });
+
     const { buffer, vertex } = setUpFullScreenQuad(device);
     this.quadVertexBuffer = buffer;
 
@@ -114,6 +126,10 @@ export class DiffusionPipeline {
             binding: 2,
             resource: trailMapIn.createView(),
           },
+          {
+            binding: 3,
+            resource: this.noise.createView(),
+          },
         ],
       });