Add basic drawing

src/pipelines/swipe/swipe-pipeline.ts

@@ -0,0 +1,126 @@
+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

@@ -0,0 +1,24 @@
+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;
+}