Improve drawing with segments

src/pipelines/diffusion/diffuse.wgsl

@@ -1,8 +1,14 @@
 struct Settings {
   size : vec2<f32>,
+  swipePrevious : vec2<f32>,
+  swipeCurrent : vec2<f32>,
   diffusionRate : f32,
   decayRate : f32,
   deltaTime : f32,
+  time : f32,
+  swipeRadius : f32,
+  swipeBlur : f32,
+  isSwipeActive : f32
 };
 
 @group(0) @binding(0) var<uniform> settings : Settings;
@@ -11,18 +17,30 @@ struct Settings {
 
 @fragment
 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
+  var current = textureSample(trailMap, Sampler, uv);
+  
+  let neighbours: vec4<f32> = (
+      textureSample(trailMap, Sampler, uv + vec2<f32>(0, 1) / settings.size)
+    + textureSample(trailMap, Sampler, uv + vec2<f32>(0, -1) / settings.size)
+    + textureSample(trailMap, Sampler, uv + vec2<f32>(-1, 0) / settings.size)
+    + textureSample(trailMap, Sampler, uv + vec2<f32>(1, 0) / settings.size)
   );
 
-  return vec4(mix(
+  if (settings.isSwipeActive == 1.0) {
+    let pa = (uv - settings.swipePrevious) * normalize(settings.size);
+    let direction = (settings.swipeCurrent - settings.swipePrevious) * normalize(settings.size);
+    let q = clamp(dot(pa, direction) / dot(direction, direction), 0, 1);
+    let distance = length(pa - direction * q) - settings.swipeRadius;
+  
+    if(distance < 0) {
+      let opacity = -distance / settings.swipeBlur;
+      return clamp(vec4(1), current, vec4(1));
+    }
+  }
+
+  return mix(
     current,
     neighbours / 4.0,
     settings.diffusionRate
-  ) * (1.0 - settings.decayRate), 1.0);
+  ) * (1.0 - settings.decayRate);
 }

src/pipelines/diffusion/diffusion-pipeline.ts

@@ -1,13 +1,19 @@
 import { setUpFullScreenQuad } from '../../utils/full-screen-quad';
 import shader from './diffuse.wgsl';
 
+import { vec2 } from 'gl-matrix';
+
 export class DiffusionPipeline {
-  private static readonly UNIFORM_COUNT = 6;
+  private static readonly UNIFORM_COUNT = 14;
 
   private readonly pipeline: GPURenderPipeline;
   private readonly uniforms: GPUBuffer;
   private readonly quadVertexBuffer: GPUBuffer;
 
+  private swipes: Array<vec2> = [
+    vec2.fromValues(Number.NaN, Number.NaN),
+    vec2.fromValues(Number.NaN, Number.NaN),
+  ];
   private bindGroup?: GPUBindGroup;
   private previousTrailMapIn?: GPUTexture;
 
@@ -46,17 +52,42 @@ export class DiffusionPipeline {
     diffusionRate,
     decayRate,
     deltaTime,
+    time,
+    swipe,
+    swipeRadius,
+    swipeBlur,
+    isSwipeActive,
   }: {
     width: number;
     height: number;
+    swipe: vec2;
     diffusionRate: number;
     decayRate: number;
     deltaTime: number;
+    time: number;
+    swipeRadius: number;
+    swipeBlur: number;
+    isSwipeActive: boolean;
   }) {
+    if (swipe) {
+      this.swipes = [...this.swipes.slice(-1), swipe];
+    }
+
     this.device.queue.writeBuffer(
       this.uniforms,
       0,
-      new Float32Array([width, height, diffusionRate, decayRate, deltaTime])
+      new Float32Array([
+        width,
+        height,
+        ...this.swipes.flatMap((s) => [s[0], s[1]]),
+        diffusionRate,
+        decayRate,
+        deltaTime,
+        time,
+        swipeRadius,
+        swipeBlur,
+        isSwipeActive ? 1.0 : 0.0,
+      ])
     );
   }
 

src/pipelines/render/render.wgsl

@@ -4,5 +4,5 @@
 
 @fragment
 fn fragment(@location(0) uv: vec2<f32>) -> @location(0) vec4<f32> {
-  return textureSample(TargetTexture, mySampler, uv) * 10.0;
+  return vec4(textureSample(TargetTexture, mySampler, uv).rgb * 1.0, 1);
 }

src/pipelines/swipe/swipe-pipeline.ts

@@ -1,126 +0,0 @@
-import { setUpFullScreenQuad } from '../../utils/full-screen-quad';
-import shader from './swipe.wgsl';
-
-import { vec2 } from 'gl-matrix';
-
-export class SwipePipeline {
-  private static readonly UNIFORM_COUNT = 8;
-
-  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,
-      fragment: {
-        module: device.createShaderModule({
-          code: shader,
-        }),
-        entryPoint: 'fragment',
-        targets: [
-          {
-            format: 'rgba16float',
-          },
-        ],
-      },
-      primitive: {
-        topology: 'triangle-strip',
-      },
-    });
-
-    this.uniforms = this.device.createBuffer({
-      size: SwipePipeline.UNIFORM_COUNT * Float32Array.BYTES_PER_ELEMENT,
-      usage: GPUBufferUsage.UNIFORM | GPUBufferUsage.COPY_DST,
-    });
-  }
-
-  public setParameters({
-    width,
-    height,
-    isSwipeActive,
-    swipe,
-    swipeRadius,
-  }: {
-    width: number;
-    height: number;
-    isSwipeActive: boolean;
-    swipe: vec2;
-    swipeRadius: number;
-  }) {
-    this.device.queue.writeBuffer(
-      this.uniforms,
-      0,
-      new Float32Array([
-        width,
-        height,
-        swipe ? swipe[0] : 0,
-        swipe ? swipe[1] : 0,
-        swipeRadius,
-        isSwipeActive ? 1 : 0,
-      ])
-    );
-  }
-
-  public execute(
-    commandEncoder: GPUCommandEncoder,
-    trailMapIn: GPUTexture,
-    trailMapOut: GPUTexture
-  ) {
-    this.ensureBindGroupExists(trailMapIn);
-
-    const renderPassDescriptor: GPURenderPassDescriptor = {
-      colorAttachments: [
-        {
-          view: trailMapOut.createView(),
-          clearValue: { r: 1.0, g: 1.0, b: 1.0, a: 1.0 },
-          loadOp: 'clear',
-          storeOp: 'store',
-        },
-      ],
-    };
-
-    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) {
-    if (this.previousTrailMapIn !== trailMapIn) {
-      this.bindGroup = this.device.createBindGroup({
-        layout: this.pipeline.getBindGroupLayout(0),
-        entries: [
-          {
-            binding: 0,
-            resource: {
-              buffer: this.uniforms,
-            },
-          },
-          {
-            binding: 1,
-            resource: this.device.createSampler({
-              magFilter: 'linear',
-              minFilter: 'linear',
-            }),
-          },
-          {
-            binding: 2,
-            resource: trailMapIn.createView(),
-          },
-        ],
-      });
-
-      this.previousTrailMapIn = trailMapIn;
-    }
-  }
-}

src/pipelines/swipe/swipe.wgsl

@@ -1,24 +0,0 @@
-struct Settings {
-  size : vec2<f32>,
-  swipe : vec2<f32>,
-  swipeRadius : f32,
-  isSwipeActive : 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) uv: vec2<f32>) -> @location(0) vec4<f32> {
-  var current = textureSample(trailMap, Sampler, uv);
-  
-  if (
-    settings.isSwipeActive == 1.0 &&
-    length((uv - settings.swipe) * normalize(settings.size)) < settings.swipeRadius
-  ) {
-    current = vec4<f32>(1);
-  }
-
-  return current;
-}