Experiment with cancer cells

src/game-loop/game-loop.ts

@@ -12,7 +12,6 @@ import { vec2 } from 'gl-matrix';
 
 export default class GameLoop {
   private context: GPUCanvasContext;
-  private adapter: GPUAdapter;
   private device: GPUDevice;
 
   private agentPipeline: AgentPipeline;
@@ -81,7 +80,7 @@ export default class GameLoop {
         position,
         angle: angle + Math.PI,
         species: 0,
-        timeToLive: Random.randomBetween(2, 10),
+        timeToLive: Random.randomBetween(10, 15000),
       };
     });
   }
@@ -119,8 +118,8 @@ export default class GameLoop {
       throw new Error('WebGPU is not supported');
     }
 
-    this.adapter = await gpu.requestAdapter();
-    this.device = await this.adapter.requestDevice(); // could request more resources
+    const adapter = await gpu.requestAdapter();
+    this.device = await adapter.requestDevice(); // could request more resources
 
     this.context = this.canvas.getContext('webgpu') as any;
     this.context.configure({

src/pipelines/agents/agent.wgsl

@@ -14,7 +14,7 @@ struct Settings {
   moveRate: f32,
   turnRate: f32,
   sensorAngle: f32,
-  sensorOffsetDst: f32,
+  sensorOffset: f32,
 };
 
 @group(0) @binding(0) var<uniform> settings: Settings;
@@ -32,11 +32,46 @@ fn main(@builtin(global_invocation_id) global_id: vec3<u32>) {
 
   var agent = agents[id];
 
+  if (agent.timeToLive <= 0.) {
+    agent.position = vec2(random(id + u32(settings.time * 10 + agent.position.x * 10000)),
+      random(id + u32(settings.time * 10 + agent.position.y * 10000)));
+    agent.angle = random(id + u32(settings.time)) * 3.14159265359 * 2.;
+    agent.species = 1;
+    agent.timeToLive = 1000;
+    agents[id] = agent;
+    return;
+  }
+
   let random = random(id + u32(settings.time * 10000 + agent.position.y * 10 + agent.position.x));
 
-  let weightForward: f32 = sense(agent, 0.);
-  let weightLeft: f32 = sense(agent, settings.sensorAngle);
-  let weightRight: f32 = sense(agent, -settings.sensorAngle);
+  let trailCurrent = sense(agent, 0, 0);
+  var weight: f32;
+  if(agent.species == 0) {
+    weight = trailCurrent.r - trailCurrent.g;
+  } else {
+    weight = trailCurrent.g - trailCurrent.r;
+  }
+  if (weight < 0) {
+    agent.timeToLive = 0;
+    return;
+  }
+  
+  let trailForward = sense(agent, settings.sensorOffset, 0);
+  let trailLeft = sense(agent, settings.sensorOffset, settings.sensorAngle);
+  let trailRight = sense(agent, settings.sensorOffset, -settings.sensorAngle);
+
+  var weightForward: f32 = trailForward.a;
+  var weightLeft: f32 = trailLeft.a;
+  var weightRight: f32 = trailRight.a;
+  if (agent.species == 0) {
+    weightForward += trailForward.r - trailForward.g;
+    weightLeft += trailLeft.r - trailLeft.g;
+    weightRight += trailRight.r - trailRight.g;
+  } else {
+    weightForward += trailForward.g - trailForward.r;
+    weightLeft += trailLeft.g - trailLeft.r;
+    weightRight += trailRight.g - trailRight.r;
+  }
 
   if (weightForward < weightLeft && weightForward < weightRight) {
     agent.angle += (random - 0.5) * 2. * settings.turnRate;
@@ -53,17 +88,23 @@ fn main(@builtin(global_invocation_id) global_id: vec3<u32>) {
     agent.angle += 3.14159265359 + random - 0.5;
   }
 
-  textureStore(TrailMapOut, vec2<i32>(newPos * settings.size), vec4(1, 0, 0, 0));
+  var trail = vec4<f32>(0, 1, 0, 0);
+  if (agent.species == 0) {
+    trail = vec4(1, 0, 0, 0);
+  }
+  textureStore(TrailMapOut, vec2<i32>(newPos * settings.size), trail);
 
   agent.position = newPos;
+  agent.timeToLive -= settings.deltaTime;
   agents[id] = agent;
 }
 
-fn sense(agent: Agent, sensorAngleOffset: f32) -> f32 {
-  let sensorAngle: f32 = agent.angle + sensorAngleOffset;
+fn sense(agent: Agent, sensorOffset: f32, sensorOffsetAngle: f32) -> vec4<f32> {
+  let sensorAngle = agent.angle + sensorOffsetAngle;
+
   let sensorDir: vec2<f32> = vec2(cos(sensorAngle), sin(sensorAngle)) / normalize(settings.size);
-  let sensorPos: vec2<f32> = agent.position + sensorDir * settings.sensorOffsetDst;
-  return length(textureLoad(TrailMapIn, vec2<i32>(sensorPos * settings.size), 0)); 
+  let sensorPos: vec2<f32> = agent.position + sensorDir * sensorOffset;
+  return textureLoad(TrailMapIn, vec2<i32>(sensorPos * settings.size), 0); 
 }
 
 fn random(state0: u32) -> f32 {

src/pipelines/diffusion/diffuse.wgsl

@@ -3,8 +3,10 @@ struct Settings {
   deltaTime: f32,
   time: f32,
   
-  diffusionRate: f32,
-  decayRate: f32,
+  diffusionRateTrails: f32,
+  decayRateTrails: f32,
+  diffusionRateBrush: f32,
+  decayRateBrush: f32,
 };
 
 @group(0) @binding(0) var<uniform> settings: Settings;
@@ -22,11 +24,17 @@ fn fragment(@location(0) uv: vec2<f32>) -> @location(0) vec4<f32> {
     + textureSample(trailMap, Sampler, uv + vec2<f32>(1, 0) / settings.size)
   ) / 4;
 
-  let mixed = mix(
-    current,
-    neighbours,
-    settings.diffusionRate
-  ) * (1.0 - settings.decayRate);
+  let mixedTrails = mix(
+    current.rgb,
+    neighbours.rgb,
+    settings.diffusionRateTrails
+  ) * (1.0 - settings.decayRateTrails);
 
-  return clamp(mixed, vec4(0), vec4(1));
+  let mixedBrush = mix(
+    current.a,
+    neighbours.a,
+    settings.diffusionRateBrush
+  ) * (1.0 - settings.decayRateBrush);
+
+  return clamp(vec4(mixedTrails, mixedBrush), vec4(0), vec4(1));
 }

src/pipelines/diffusion/diffusion-pipeline.ts

@@ -5,7 +5,7 @@ import shader from './diffuse.wgsl';
 import { DiffusionSettings } from './diffusion-settings';
 
 export class DiffusionPipeline {
-  private static readonly UNIFORM_COUNT = 16;
+  private static readonly UNIFORM_COUNT = 18;
 
   private readonly pipeline: GPURenderPipeline;
   private readonly uniforms: GPUBuffer;
@@ -45,8 +45,10 @@ export class DiffusionPipeline {
     canvasSize,
     deltaTime,
     time,
-    diffusionRate,
-    decayRate,
+    diffusionRateTrails,
+    decayRateTrails,
+    diffusionRateBrush,
+    decayRateBrush,
   }: CommonParameters & DiffusionSettings) {
     this.device.queue.writeBuffer(
       this.uniforms,
@@ -56,8 +58,10 @@ export class DiffusionPipeline {
         canvasSize[1],
         deltaTime,
         time,
-        diffusionRate,
-        decayRate,
+        diffusionRateTrails,
+        decayRateTrails,
+        diffusionRateBrush,
+        decayRateBrush,
       ])
     );
   }

src/pipelines/diffusion/diffusion-settings.ts

@@ -1,4 +1,6 @@
 export interface DiffusionSettings {
-  diffusionRate: number;
-  decayRate: number;
+  diffusionRateTrails: number;
+  decayRateTrails: number;
+  diffusionRateBrush: number;
+  decayRateBrush: number;
 }

src/settings.ts

@@ -32,10 +32,12 @@ export const settings: GameLoopSettings &
   sensorAngleDegrees: 30,
   sensorOffsetDst: 0.025,
 
-  decayRate: 0.005,
-  diffusionRate: 0.9,
+  diffusionRateTrails: 0.8,
+  decayRateTrails: 0.03,
+  diffusionRateBrush: 0.9,
+  decayRateBrush: 0.003,
 
-  brushColor: palette.beige,
+  brushColor: palette.yellow,
   speciesColorA: palette.yellow,
   speciesColorB: palette.green,
 };