feat: layer the nightdrive sky and atmosphere

src/journey/scroll-drive-controller.ts

@@ -74,13 +74,14 @@ export function createScrollDriveController(): ScrollDriveController {
       return cruiseSnapshot(input);
     }
 
+    const deltaY = input.scrollY - previousSample.scrollY;
+    const direction: -1 | 0 | 1 = deltaY > 0 ? 1 : deltaY < 0 ? -1 : 0;
     if (elapsedMs > BACKGROUND_GAP_MS) {
       previousSample = { ...input };
       smoothedAcceleration = 0;
-      return cruiseSnapshot(input);
+      return { ...cruiseSnapshot(input), direction };
     }
 
-    const deltaY = input.scrollY - previousSample.scrollY;
     const rawSpeed = Math.abs(deltaY) / elapsedMs;
     const impulse = clamp(rawSpeed / MAX_RAW_SPEED, 0, 1);
     const timeConstantMs = impulse > smoothedAcceleration
@@ -93,7 +94,6 @@ export function createScrollDriveController(): ScrollDriveController {
     }
     previousSample = { ...input };
 
-    const direction: -1 | 0 | 1 = deltaY > 0 ? 1 : deltaY < 0 ? -1 : 0;
     return {
       scrollY: input.scrollY,
       routeProgress: routeProgress(input),

src/scene/post-processing.ts

@@ -0,0 +1,92 @@
+import * as THREE from 'three';
+import { EffectComposer } from 'three/examples/jsm/postprocessing/EffectComposer.js';
+import { RenderPass } from 'three/examples/jsm/postprocessing/RenderPass.js';
+import { UnrealBloomPass } from 'three/examples/jsm/postprocessing/UnrealBloomPass.js';
+import type { SceneResourceBag } from '@/scene/resources';
+
+export interface PostProcessor {
+  resize(width: number, height: number, pixelRatio: number): void;
+  render(scene: unknown, camera: unknown): void;
+  dispose(): void;
+}
+
+interface ComposerLike {
+  addPass(pass: unknown): void;
+  setPixelRatio(pixelRatio: number): void;
+  setSize(width: number, height: number): void;
+  render(): void;
+  dispose(): void;
+}
+
+interface RenderPassLike {
+  scene: unknown;
+  camera: unknown;
+  dispose(): void;
+}
+
+interface BloomPassLike {
+  dispose(): void;
+}
+
+export interface PostProcessingFactories {
+  createComposer(renderer: unknown): ComposerLike;
+  createRenderPass(scene: unknown, camera: unknown): RenderPassLike;
+  createBloomPass(): BloomPassLike;
+}
+
+const productionFactories: PostProcessingFactories = {
+  createComposer: (renderer) => new EffectComposer(renderer),
+  createRenderPass: (scene, camera) => new RenderPass(scene, camera),
+  createBloomPass: () => new UnrealBloomPass(
+    new THREE.Vector2(1, 1),
+    0.46,
+    0.32,
+    0.84,
+  ),
+};
+
+export function createPostProcessor(
+  resources: SceneResourceBag,
+  renderer: unknown,
+  factories: PostProcessingFactories = productionFactories,
+): PostProcessor {
+  const composer = factories.createComposer(renderer);
+  const renderPass = factories.createRenderPass(new THREE.Scene(), new THREE.Camera());
+  const bloomPass = factories.createBloomPass();
+  composer.addPass(renderPass);
+  composer.addPass(bloomPass);
+  let disposed = false;
+
+  const processor: PostProcessor = {
+    resize(width, height, pixelRatio) {
+      if (disposed) return;
+      composer.setPixelRatio(clamp(pixelRatio, 0.5, 2));
+      composer.setSize(
+        Math.max(1, Math.floor(finiteOr(width, 1))),
+        Math.max(1, Math.floor(finiteOr(height, 1))),
+      );
+    },
+    render(scene, camera) {
+      if (disposed) return;
+      renderPass.scene = scene;
+      renderPass.camera = camera;
+      composer.render();
+    },
+    dispose() {
+      if (disposed) return;
+      disposed = true;
+      renderPass.dispose();
+      bloomPass.dispose();
+      composer.dispose();
+    },
+  };
+  return resources.own('pass', processor);
+}
+
+function finiteOr(value: number, fallback: number): number {
+  return Number.isFinite(value) ? value : fallback;
+}
+
+function clamp(value: number, minimum: number, maximum: number): number {
+  return THREE.MathUtils.clamp(finiteOr(value, minimum), minimum, maximum);
+}

src/scene/render-quality.ts

@@ -5,8 +5,9 @@ export interface RenderQualitySettings {
   roadSegments: number;
   terrainSegments: number;
   terrainOctaves: 1 | 2 | 3;
-  particleCount: number;
+  starCount: number;
   streakCount: number;
+  postScale: number;
   postEffects: boolean;
 }
 
@@ -16,8 +17,9 @@ const settings: Readonly<Record<LiveQualityTier, Omit<RenderQualitySettings, 'pi
     roadSegments: 192,
     terrainSegments: 96,
     terrainOctaves: 3,
-    particleCount: 384,
+    starCount: 384,
     streakCount: 48,
+    postScale: 1,
     postEffects: true,
   },
   medium: {
@@ -25,8 +27,9 @@ const settings: Readonly<Record<LiveQualityTier, Omit<RenderQualitySettings, 'pi
     roadSegments: 144,
     terrainSegments: 64,
     terrainOctaves: 2,
-    particleCount: 192,
+    starCount: 192,
     streakCount: 28,
+    postScale: 0.7,
     postEffects: true,
   },
   low: {
@@ -34,8 +37,9 @@ const settings: Readonly<Record<LiveQualityTier, Omit<RenderQualitySettings, 'pi
     roadSegments: 96,
     terrainSegments: 32,
     terrainOctaves: 1,
-    particleCount: 64,
+    starCount: 64,
     streakCount: 12,
+    postScale: 0,
     postEffects: false,
   },
 };
@@ -52,8 +56,9 @@ export function renderQualityFor(
     roadSegments: selected.roadSegments,
     terrainSegments: selected.terrainSegments,
     terrainOctaves: selected.terrainOctaves,
-    particleCount: selected.particleCount,
+    starCount: selected.starCount,
     streakCount: selected.streakCount,
+    postScale: selected.postScale,
     postEffects: selected.postEffects,
   };
 }

src/scene/three.d.ts

@@ -2,3 +2,6 @@
 // The scene remains isolated behind typed application interfaces; this ambient declaration
 // prevents the untyped renderer dependency from leaking into Vue or journey modules.
 declare module 'three';
+declare module 'three/examples/jsm/postprocessing/EffectComposer.js';
+declare module 'three/examples/jsm/postprocessing/RenderPass.js';
+declare module 'three/examples/jsm/postprocessing/UnrealBloomPass.js';

src/scene/world/atmosphere.ts

@@ -0,0 +1,273 @@
+import * as THREE from 'three';
+import type { RenderQualitySettings } from '@/scene/render-quality';
+import type { SceneResourceBag } from '@/scene/resources';
+import type { MutableChapterPalette } from '@/scene/world/palette';
+import { CHAPTER_PALETTES } from '@/scene/world/palette';
+
+export interface AtmosphereWorld {
+  group: WorldGroup;
+  update(
+    distance: number,
+    speed: number,
+    acceleration: number,
+    palette: Readonly<MutableChapterPalette>,
+  ): void;
+}
+
+interface WorldGroup {
+  add(...objects: unknown[]): void;
+  getObjectByName(name: string): unknown;
+}
+
+export function createAtmosphere(
+  resources: SceneResourceBag,
+  quality: RenderQualitySettings,
+): AtmosphereWorld {
+  const group = new THREE.Group();
+  group.name = 'atmosphere-world';
+  const night = CHAPTER_PALETTES['deep-night'];
+
+  const skyGeometry = resources.own('geometry', new THREE.PlaneGeometry(520, 280));
+  const skyMaterial = resources.own('material', new THREE.ShaderMaterial({
+    uniforms: {
+      uSkyColor: { value: new THREE.Color(night.sky) },
+      uHazeColor: { value: new THREE.Color(night.haze) },
+      uWarmth: { value: night.warmth },
+    },
+    vertexShader: `
+      varying vec2 vSkyUv;
+      void main() {
+        vSkyUv = uv;
+        gl_Position = projectionMatrix * modelViewMatrix * vec4(position, 1.0);
+      }
+    `,
+    fragmentShader: `
+      uniform vec3 uSkyColor;
+      uniform vec3 uHazeColor;
+      uniform float uWarmth;
+      varying vec2 vSkyUv;
+      void main() {
+        float horizon = 1.0 - smoothstep(0.08, 0.72, vSkyUv.y);
+        float upperNight = smoothstep(0.35, 1.0, vSkyUv.y);
+        vec3 color = mix(uSkyColor, uHazeColor, horizon * (0.38 + uWarmth * 0.2));
+        color *= mix(1.04, 0.72, upperNight);
+        gl_FragColor = vec4(color, 1.0);
+      }
+    `,
+    depthWrite: false,
+    depthTest: false,
+    fog: false,
+    toneMapped: true,
+  }));
+  const sky = new THREE.Mesh(skyGeometry, skyMaterial);
+  sky.name = 'atmosphere-sky';
+  sky.position.set(0, 69, -300);
+  sky.renderOrder = -100;
+  group.add(sky);
+
+  const starGeometry = resources.own('geometry', createStarGeometry(quality.starCount));
+  const starMaterial = resources.own('material', new THREE.ShaderMaterial({
+    uniforms: {
+      uVisibility: { value: night.starVisibility },
+      uDistance: { value: 0 },
+      uColor: { value: new THREE.Color(0xb9ecf2) },
+    },
+    vertexShader: `
+      attribute float starSize;
+      attribute float brightness;
+      uniform float uDistance;
+      varying float vBrightness;
+      void main() {
+        vec3 star = position;
+        star.x += sin(position.z * 0.017 + uDistance * 0.004) * 0.08;
+        vec4 viewPosition = modelViewMatrix * vec4(star, 1.0);
+        vBrightness = brightness;
+        gl_PointSize = starSize * (250.0 / max(1.0, -viewPosition.z));
+        gl_Position = projectionMatrix * viewPosition;
+      }
+    `,
+    fragmentShader: `
+      uniform vec3 uColor;
+      uniform float uVisibility;
+      varying float vBrightness;
+      void main() {
+        float radius = distance(gl_PointCoord, vec2(0.5));
+        float point = 1.0 - smoothstep(0.2, 0.5, radius);
+        gl_FragColor = vec4(uColor, point * vBrightness * uVisibility);
+      }
+    `,
+    transparent: true,
+    depthWrite: false,
+    depthTest: true,
+    blending: THREE.AdditiveBlending,
+    toneMapped: true,
+  }));
+  const stars = new THREE.Points(starGeometry, starMaterial);
+  stars.name = 'atmosphere-stars';
+  stars.frustumCulled = false;
+  group.add(stars);
+
+  const hazeGeometry = resources.own('geometry', new THREE.PlaneGeometry(260, 58));
+  const nearHazeMaterial = resources.own('material', createHazeMaterial(night.haze, 0.2));
+  const farHazeMaterial = resources.own('material', createHazeMaterial(night.haze, 0.12));
+  const farHaze = new THREE.Mesh(hazeGeometry, farHazeMaterial);
+  farHaze.name = 'horizon-haze-far';
+  farHaze.position.set(0, 10, -214);
+  farHaze.scale.set(1.35, 1.1, 1);
+  group.add(farHaze);
+  const nearHaze = new THREE.Mesh(hazeGeometry, nearHazeMaterial);
+  nearHaze.name = 'horizon-haze-near';
+  nearHaze.position.set(0, 8, -132);
+  group.add(nearHaze);
+
+  const streakGeometry = resources.own('geometry', createStreakGeometry(quality.streakCount));
+  const streakMaterial = resources.own('material', new THREE.ShaderMaterial({
+    uniforms: {
+      uDistance: { value: 0 },
+      uAcceleration: { value: 0 },
+      uVisibility: { value: 0 },
+      uColor: { value: new THREE.Color(0x79dae5) },
+    },
+    vertexShader: `
+      attribute float endFactor;
+      uniform float uDistance;
+      uniform float uAcceleration;
+      varying float vTail;
+      void main() {
+        vec3 streak = position;
+        float depthCycle = mod(streak.z + uDistance * 1.4 + 280.0, 286.0) - 280.0;
+        streak.z = depthCycle + endFactor * (1.2 + uAcceleration * 18.0);
+        vTail = endFactor;
+        gl_Position = projectionMatrix * modelViewMatrix * vec4(streak, 1.0);
+      }
+    `,
+    fragmentShader: `
+      uniform vec3 uColor;
+      uniform float uVisibility;
+      varying float vTail;
+      void main() {
+        gl_FragColor = vec4(uColor, uVisibility * mix(0.15, 0.72, vTail));
+      }
+    `,
+    transparent: true,
+    depthWrite: false,
+    depthTest: true,
+    blending: THREE.AdditiveBlending,
+    toneMapped: true,
+  }));
+  const streaks = new THREE.LineSegments(streakGeometry, streakMaterial);
+  streaks.name = 'atmosphere-streaks';
+  streaks.frustumCulled = false;
+  group.add(streaks);
+
+  return {
+    group,
+    update(distance, speed, acceleration, palette) {
+      const safeAcceleration = clamp01(acceleration);
+      const visibility = smoothstep(0.18, 0.82, safeAcceleration) * palette.streakEnergy;
+      starMaterial.uniforms.uDistance.value = finiteOrZero(distance);
+      starMaterial.uniforms.uVisibility.value = palette.starVisibility;
+      streakMaterial.uniforms.uDistance.value = finiteOrZero(distance) * (0.72 + clamp01(speed) * 0.28);
+      streakMaterial.uniforms.uAcceleration.value = safeAcceleration;
+      streakMaterial.uniforms.uVisibility.value = visibility;
+      skyMaterial.uniforms.uSkyColor.value.copy(palette.sky);
+      skyMaterial.uniforms.uHazeColor.value.copy(palette.haze);
+      skyMaterial.uniforms.uWarmth.value = palette.warmth;
+      nearHazeMaterial.uniforms.uColor.value.copy(palette.haze);
+      farHazeMaterial.uniforms.uColor.value.copy(palette.haze);
+      nearHazeMaterial.uniforms.uEnergy.value = 0.16 + palette.warmth * 0.08;
+      farHazeMaterial.uniforms.uEnergy.value = 0.09 + palette.warmth * 0.06;
+    },
+  };
+}
+
+function createStarGeometry(count: number) {
+  const positions = new Float32Array(count * 3);
+  const sizes = new Float32Array(count);
+  const brightness = new Float32Array(count);
+  for (let index = 0; index < count; index += 1) {
+    const offset = index * 3;
+    positions[offset] = seeded(index, 11) * 210 - 105;
+    positions[offset + 1] = 8 + seeded(index, 23) * 72;
+    positions[offset + 2] = -18 - seeded(index, 37) * 270;
+    sizes[index] = 2.4 + seeded(index, 53) * 4.8;
+    brightness[index] = 0.28 + seeded(index, 71) * 0.72;
+  }
+  const geometry = new THREE.BufferGeometry();
+  geometry.setAttribute('position', new THREE.BufferAttribute(positions, 3));
+  geometry.setAttribute('starSize', new THREE.BufferAttribute(sizes, 1));
+  geometry.setAttribute('brightness', new THREE.BufferAttribute(brightness, 1));
+  return geometry;
+}
+
+function createStreakGeometry(count: number) {
+  const positions = new Float32Array(count * 2 * 3);
+  const ends = new Float32Array(count * 2);
+  for (let index = 0; index < count; index += 1) {
+    const x = (seeded(index, 101) > 0.5 ? 1 : -1) * (12 + seeded(index, 103) * 52);
+    const y = 0.8 + seeded(index, 107) * 12;
+    const z = -8 - seeded(index, 109) * 272;
+    const offset = index * 6;
+    positions[offset] = x;
+    positions[offset + 1] = y;
+    positions[offset + 2] = z;
+    positions[offset + 3] = x;
+    positions[offset + 4] = y + seeded(index, 113) * 0.8;
+    positions[offset + 5] = z;
+    ends[index * 2] = 0;
+    ends[index * 2 + 1] = 1;
+  }
+  const geometry = new THREE.BufferGeometry();
+  geometry.setAttribute('position', new THREE.BufferAttribute(positions, 3));
+  geometry.setAttribute('endFactor', new THREE.BufferAttribute(ends, 1));
+  return geometry;
+}
+
+function createHazeMaterial(color: number, energy: number) {
+  return new THREE.ShaderMaterial({
+    uniforms: {
+      uColor: { value: new THREE.Color(color) },
+      uEnergy: { value: energy },
+    },
+    vertexShader: `
+      varying vec2 vHazeUv;
+      void main() {
+        vHazeUv = uv;
+        gl_Position = projectionMatrix * modelViewMatrix * vec4(position, 1.0);
+      }
+    `,
+    fragmentShader: `
+      uniform vec3 uColor;
+      uniform float uEnergy;
+      varying vec2 vHazeUv;
+      void main() {
+        float vertical = 1.0 - smoothstep(0.04, 0.84, abs(vHazeUv.y - 0.42) * 1.9);
+        float horizontal = 1.0 - smoothstep(0.26, 0.5, abs(vHazeUv.x - 0.5));
+        gl_FragColor = vec4(uColor, vertical * horizontal * uEnergy);
+      }
+    `,
+    transparent: true,
+    depthWrite: false,
+    depthTest: true,
+    blending: THREE.AdditiveBlending,
+    toneMapped: true,
+  });
+}
+
+function seeded(index: number, salt: number): number {
+  const result = Math.sin((index + 1) * 91.713 + salt * 17.17) * 43_758.5453;
+  return result - Math.floor(result);
+}
+
+function finiteOrZero(value: number): number {
+  return Number.isFinite(value) ? value : 0;
+}
+
+function clamp01(value: number): number {
+  return THREE.MathUtils.clamp(finiteOrZero(value), 0, 1);
+}
+
+function smoothstep(edge0: number, edge1: number, value: number): number {
+  const progress = THREE.MathUtils.clamp((value - edge0) / (edge1 - edge0), 0, 1);
+  return progress * progress * (3 - 2 * progress);
+}

src/scene/world/environment.ts

@@ -1,5 +1,5 @@
 import * as THREE from 'three';
-import type { EnvironmentChapter, JourneySnapshot } from '@/journey/types';
+import type { JourneySnapshot } from '@/journey/types';
 import type { SceneResourceBag } from '@/scene/resources';
 import type { SceneBuildContext, SceneGeneration } from '@/scene/types';
 import { renderQualityFor } from '@/scene/render-quality';
@@ -8,21 +8,18 @@ import { createTerrain } from '@/scene/world/terrain';
 import { createSun } from '@/scene/world/sun';
 import { createCar } from '@/scene/world/car';
 import { createSign } from '@/scene/world/sign';
-import { createParticles } from '@/scene/world/particles';
+import { createAtmosphere } from '@/scene/world/atmosphere';
+import { createPostProcessor } from '@/scene/post-processing';
+import {
+  createMutableChapterPalette,
+  writeChapterPalette,
+  type MutableChapterPalette,
+} from '@/scene/world/palette';
 import { isTestFault, recordTestFaultEvent } from '@/testing/fault-hooks';
 
 declare const __PORTFOLIO_TEST_BUILD__: boolean;
 const TEST_BUILD = typeof __PORTFOLIO_TEST_BUILD__ !== 'undefined' && __PORTFOLIO_TEST_BUILD__;
 
-const skyColors: Readonly<Record<EnvironmentChapter, number>> = {
-  'deep-night': 0x040713,
-  systems: 0x060918,
-  infrastructure: 0x080b1d,
-  builds: 0x0d1025,
-  'pre-dawn': 0x18152c,
-  destination: 0x2b2035,
-};
-
 export function createChaseCamera(aspect = 1) {
   const camera = new THREE.PerspectiveCamera(52, aspect, 0.1, 320);
   camera.position.set(0, 4.8, 12.5);
@@ -62,9 +59,11 @@ export async function createProceduralSceneGeneration(
   renderer.toneMappingExposure = 1.05;
 
   const scene = new THREE.Scene();
-  const background = new THREE.Color(skyColors['deep-night']);
+  const currentPalette = createMutableChapterPalette('deep-night');
+  const targetPalette = createMutableChapterPalette('deep-night');
+  const background = currentPalette.sky.clone();
   scene.background = background;
-  scene.fog = new THREE.FogExp2(0x080c18, 0.012);
+  scene.fog = new THREE.FogExp2(currentPalette.fog.getHex(), 0.012);
   const camera = createChaseCamera();
 
   const ambient = new THREE.HemisphereLight(0x6aa9c5, 0x100812, 1.25);
@@ -78,43 +77,19 @@ export async function createProceduralSceneGeneration(
   const sun = createSun(context.resources);
   const car = createCar(context.resources);
   const sign = createSign(context.resources);
-  const particles = createParticles(context.resources, quality.particleCount);
+  const atmosphere = createAtmosphere(context.resources, quality);
-  scene.add(road.group, terrain.group, sun.mesh, car.group, sign.group, particles.points);
+  scene.add(
+    atmosphere.group,
+    road.group,
+    terrain.group,
+    sun.group,
+    car.group,
+    sign.group,
+  );
 
-  const postTarget = quality.postEffects
+  const postProcessor = quality.postEffects
-    ? context.resources.own('target', new THREE.WebGLRenderTarget(1, 1, {
+    ? createPostProcessor(context.resources, renderer)
-      depthBuffer: true,
-      minFilter: THREE.LinearFilter,
-      magFilter: THREE.LinearFilter,
-    }))
     : null;
-  const postScene = postTarget ? new THREE.Scene() : null;
-  const postCamera = postTarget ? new THREE.OrthographicCamera(-1, 1, 1, -1, 0, 1) : null;
-  if (postScene && postTarget) {
-    const postGeometry = context.resources.own('geometry', new THREE.PlaneGeometry(2, 2));
-    const postMaterial = context.resources.own('material', new THREE.ShaderMaterial({
-      uniforms: { source: { value: postTarget.texture } },
-      vertexShader: `
-        varying vec2 vUv;
-        void main() {
-          vUv = uv;
-          gl_Position = vec4(position.xy, 0.0, 1.0);
-        }
-      `,
-      fragmentShader: `
-        uniform sampler2D source;
-        varying vec2 vUv;
-        void main() {
-          vec4 color = texture2D(source, vUv);
-          float vignette = smoothstep(0.92, 0.24, distance(vUv, vec2(0.5)));
-          gl_FragColor = vec4(color.rgb * mix(0.82, 1.0, vignette), color.a);
-        }
-      `,
-      depthTest: false,
-      depthWrite: false,
-    }));
-    postScene.add(new THREE.Mesh(postGeometry, postMaterial));
-  }
   let width = 0;
   let height = 0;
   let driveDistance = 0;
@@ -132,10 +107,7 @@ export async function createProceduralSceneGeneration(
     renderer.setSize(width, height, false);
     camera.aspect = width / height;
     camera.updateProjectionMatrix();
-    postTarget?.setSize(
+    postProcessor?.resize(width, height, quality.pixelRatio * quality.postScale);
-      Math.max(1, Math.floor(width * quality.pixelRatio)),
-      Math.max(1, Math.floor(height * quality.pixelRatio)),
-    );
     if (TEST_BUILD && context.quality !== 'medium') {
       window.__PORTFOLIO_PERFORMANCE__?.recordRuntimeAllocation(context.resources.gpuBudgetSnapshot({
         tier: context.quality,
@@ -176,6 +148,8 @@ export async function createProceduralSceneGeneration(
       resize();
       const deltaSeconds = lastNow === null ? 0 : Math.min(0.1, Math.max(0, (now - lastNow) / 1000));
       lastNow = now;
+      writeChapterPalette(targetPalette, snapshot.chapter, snapshot.chapter, 0);
+      dampPalette(currentPalette, targetPalette, deltaSeconds);
       driveDistance += snapshot.driveSpeed * deltaSeconds * 18;
       road.update(driveDistance, snapshot.driveSpeed, snapshot.acceleration);
       terrain.update(
@@ -183,22 +157,27 @@ export async function createProceduralSceneGeneration(
         snapshot.driveSpeed,
         snapshot.chapter,
         snapshot.routeProgress,
+        currentPalette,
       );
-      sun.update(snapshot.chapter, snapshot.routeProgress);
+      sun.update(currentPalette, snapshot.routeProgress);
       car.update(snapshot.driveSpeed, snapshot.acceleration, now / 1000);
       sign.update(snapshot.sign);
-      particles.update(driveDistance, snapshot.driveSpeed, snapshot.acceleration);
+      atmosphere.update(
-      background.setHex(skyColors[snapshot.chapter]);
+        driveDistance,
+        snapshot.driveSpeed,
+        snapshot.acceleration,
+        currentPalette,
+      );
+      background.copy(currentPalette.sky);
+      scene.fog.color.copy(currentPalette.fog);
+      scene.fog.density = 0.0105 + (1 - currentPalette.warmth) * 0.0025;
       const fov = 52 + Math.min(7, snapshot.acceleration * 4.5);
       if (camera.fov !== fov) {
         camera.fov = fov;
         camera.updateProjectionMatrix();
       }
-      if (postTarget) {
+      if (postProcessor) {
-        renderer.setRenderTarget(postTarget);
+        postProcessor.render(scene, camera);
-        renderer.render(scene, camera);
-        renderer.setRenderTarget(null);
-        renderer.render(postScene, postCamera);
       } else {
         renderer.render(scene, camera);
       }
@@ -211,3 +190,21 @@ export async function createProceduralSceneGeneration(
     },
   };
 }
+
+function dampPalette(
+  current: MutableChapterPalette,
+  target: Readonly<MutableChapterPalette>,
+  deltaSeconds: number,
+): void {
+  const mix = 1 - Math.exp(-Math.max(0, deltaSeconds) * 2.8);
+  current.sky.lerp(target.sky, mix);
+  current.fog.lerp(target.fog, mix);
+  current.terrainLow.lerp(target.terrainLow, mix);
+  current.terrainHigh.lerp(target.terrainHigh, mix);
+  current.sun.lerp(target.sun, mix);
+  current.haze.lerp(target.haze, mix);
+  current.warmth = THREE.MathUtils.lerp(current.warmth, target.warmth, mix);
+  current.terrainEnergy = THREE.MathUtils.lerp(current.terrainEnergy, target.terrainEnergy, mix);
+  current.starVisibility = THREE.MathUtils.lerp(current.starVisibility, target.starVisibility, mix);
+  current.streakEnergy = THREE.MathUtils.lerp(current.streakEnergy, target.streakEnergy, mix);
+}

src/scene/world/palette.ts

@@ -29,7 +29,9 @@ export interface MutableChapterPalette {
 
 export interface MutableColor {
   clone(): MutableColor;
+  copy(source: MutableColor): MutableColor;
   getHex(): number;
+  lerp(target: MutableColor, progress: number): MutableColor;
   lerpColors(from: MutableColor, to: MutableColor, progress: number): MutableColor;
   setHex(value: number): MutableColor;
 }

src/scene/world/particles.ts

@@ -1,40 +0,0 @@
-import * as THREE from 'three';
-import type { SceneResourceBag } from '@/scene/resources';
-
-export function createParticles(resources: SceneResourceBag, count: number) {
-  const positions = new Float32Array(count * 3);
-  for (let index = 0; index < count; index += 1) {
-    const offset = index * 3;
-    positions[offset] = seeded(index * 3) * 30 - 15;
-    positions[offset + 1] = seeded(index * 3 + 1) * 7 + 0.2;
-    positions[offset + 2] = -(seeded(index * 3 + 2) * 150);
-  }
-  const geometry = resources.own('geometry', new THREE.BufferGeometry());
-  geometry.setAttribute('position', new THREE.BufferAttribute(positions, 3));
-  const material = resources.own('material', new THREE.PointsMaterial({
-    color: 0xa8f5ff,
-    size: 0.07,
-    transparent: true,
-    opacity: 0.42,
-    depthWrite: false,
-  }));
-  const points = new THREE.Points(geometry, material);
-
-  return {
-    points,
-    update(distance: number, speed: number, acceleration: number) {
-      points.position.z = modulo(distance * (1 + speed * 2), 150);
-      material.opacity = Math.min(0.78, 0.25 + speed * 0.28 + acceleration * 0.18);
-      material.size = 0.055 + Math.min(0.1, speed * 0.04);
-    },
-  };
-}
-
-function seeded(value: number): number {
-  const result = Math.sin(value * 91.713 + 17.17) * 43758.5453;
-  return result - Math.floor(result);
-}
-
-function modulo(value: number, divisor: number): number {
-  return ((value % divisor) + divisor) % divisor;
-}

src/scene/world/sun.ts

@@ -1,33 +1,153 @@
 import * as THREE from 'three';
-import type { EnvironmentChapter } from '@/journey/types';
 import type { SceneResourceBag } from '@/scene/resources';
+import type { MutableChapterPalette } from '@/scene/world/palette';
+import { CHAPTER_PALETTES } from '@/scene/world/palette';
 
-const chapterWarmth: Readonly<Record<EnvironmentChapter, number>> = {
+export interface SunWorld {
-  'deep-night': 0,
+  group: WorldGroup;
-  systems: 0.12,
+  update(palette: Readonly<MutableChapterPalette>, routeProgress: number): void;
-  infrastructure: 0.24,
+}
-  builds: 0.42,
+
-  'pre-dawn': 0.68,
+interface WorldGroup {
-  destination: 1,
+  add(...objects: unknown[]): void;
+  getObjectByName(name: string): unknown;
+}
+
+export function createSun(resources: SceneResourceBag): SunWorld {
+  const group = new THREE.Group();
+  group.name = 'sun-world';
+  const night = CHAPTER_PALETTES['deep-night'];
+  const sunColor = new THREE.Color(night.sun);
+  const uniforms = {
+    uColor: { value: sunColor },
+    uScanBands: { value: 14 },
+    uWarmth: { value: night.warmth },
+    uRouteProgress: { value: 0 },
   };
+  const geometry = resources.own('geometry', new THREE.CircleGeometry(20, 96));
+  const material = resources.own('material', new THREE.ShaderMaterial({
+    uniforms,
+    vertexShader: `
+      varying vec2 vSunUv;
 
-export function createSun(resources: SceneResourceBag) {
+      void main() {
-  const geometry = resources.own('geometry', new THREE.CircleGeometry(18, 64));
+        vSunUv = uv;
-  const material = resources.own('material', new THREE.MeshBasicMaterial({
+        gl_Position = projectionMatrix * modelViewMatrix * vec4(position, 1.0);
-    color: 0xff6f83,
+      }
+    `,
+    fragmentShader: `
+      uniform vec3 uColor;
+      uniform float uScanBands;
+      uniform float uWarmth;
+      uniform float uRouteProgress;
+      varying vec2 vSunUv;
+
+      void main() {
+        float radius = distance(vSunUv, vec2(0.5));
+        float softEdge = 1.0 - smoothstep(0.435, 0.5, radius);
+        float lowerDisc = 1.0 - smoothstep(0.42, 0.76, vSunUv.y);
+        float scanBand = smoothstep(0.16, 0.28, fract(vSunUv.y * uScanBands));
+        float bandCut = mix(1.0, 0.32 + scanBand * 0.68, lowerDisc * 0.82);
+        float horizonFade = smoothstep(0.02, 0.14, vSunUv.y);
+        float luminance = 0.72 + uWarmth * 0.18 + uRouteProgress * 0.06;
+        gl_FragColor = vec4(uColor * luminance, softEdge * bandCut * horizonFade * 0.9);
+      }
+    `,
     transparent: true,
-    opacity: 0.82,
+    depthWrite: false,
-    fog: false,
+    depthTest: true,
+    blending: THREE.AdditiveBlending,
+    toneMapped: true,
   }));
-  const mesh = new THREE.Mesh(geometry, material);
+  const disc = new THREE.Mesh(geometry, material);
-  mesh.position.set(0, 12, -128);
+  disc.name = 'sun-disc';
+  disc.position.set(0, 11.5, -142);
+  group.add(disc);
+
+  const haloTexture = resources.own('texture', createHaloTexture());
+  const haloMaterial = resources.own('material', new THREE.SpriteMaterial({
+    map: haloTexture,
+    color: sunColor.clone(),
+    transparent: true,
+    opacity: 0.24,
+    depthWrite: false,
+    depthTest: true,
+    blending: THREE.AdditiveBlending,
+    toneMapped: true,
+  }));
+  const halo = new THREE.Sprite(haloMaterial);
+  halo.name = 'sun-halo';
+  halo.position.copy(disc.position);
+  halo.position.z -= 0.5;
+  halo.scale.set(57, 43, 1);
+  group.add(halo);
 
   return {
-    mesh,
+    group,
-    update(chapter: EnvironmentChapter, routeProgress: number) {
+    update(palette, routeProgress) {
-      const warmth = Math.max(chapterWarmth[chapter], routeProgress);
+      const progress = clamp01(routeProgress);
-      material.color.setRGB(1, 0.34 + warmth * 0.24, 0.42 + warmth * 0.22);
+      sunColor.copy(palette.sun);
-      mesh.position.y = 12 + warmth * 5;
+      haloMaterial.color.copy(palette.sun);
+      uniforms.uWarmth.value = clamp01(palette.warmth);
+      uniforms.uRouteProgress.value = progress;
+      haloMaterial.opacity = 0.18 + palette.warmth * 0.12;
+      disc.position.y = 11.5 + palette.warmth * 4.8;
+      halo.position.y = disc.position.y;
     },
   };
 }
+
+function createHaloTexture() {
+  const size = 64;
+  if (typeof document !== 'undefined') {
+    const canvas = document.createElement('canvas');
+    canvas.width = size;
+    canvas.height = size;
+    let context: CanvasRenderingContext2D | null = null;
+    try {
+      context = canvas.getContext('2d');
+    } catch {
+      context = null;
+    }
+    if (context) {
+      const gradient = context.createRadialGradient(
+        size / 2,
+        size / 2,
+        0,
+        size / 2,
+        size / 2,
+        size / 2,
+      );
+      gradient.addColorStop(0, 'rgb(255 255 255 / 90%)');
+      gradient.addColorStop(0.26, 'rgb(255 255 255 / 32%)');
+      gradient.addColorStop(1, 'rgb(255 255 255 / 0%)');
+      context.fillStyle = gradient;
+      context.fillRect(0, 0, size, size);
+      const texture = new THREE.CanvasTexture(canvas);
+      texture.colorSpace = THREE.SRGBColorSpace;
+      texture.generateMipmaps = false;
+      return texture;
+    }
+  }
+
+  const pixels = new Uint8Array(size * size * 4);
+  for (let y = 0; y < size; y += 1) {
+    for (let x = 0; x < size; x += 1) {
+      const distance = Math.hypot(x - size / 2, y - size / 2) / (size / 2);
+      const alpha = Math.round(255 * Math.max(0, 1 - distance) ** 2.4);
+      const offset = (y * size + x) * 4;
+      pixels[offset] = 255;
+      pixels[offset + 1] = 255;
+      pixels[offset + 2] = 255;
+      pixels[offset + 3] = alpha;
+    }
+  }
+  const texture = new THREE.DataTexture(pixels, size, size, THREE.RGBAFormat);
+  texture.needsUpdate = true;
+  texture.generateMipmaps = false;
+  return texture;
+}
+
+function clamp01(value: number): number {
+  return Number.isFinite(value) ? THREE.MathUtils.clamp(value, 0, 1) : 0;
+}

src/scene/world/terrain.ts

@@ -2,7 +2,7 @@ import * as THREE from 'three';
 import type { EnvironmentChapter } from '@/journey/types';
 import type { RenderQualitySettings } from '@/scene/render-quality';
 import type { SceneResourceBag } from '@/scene/resources';
-import { CHAPTER_PALETTES } from '@/scene/world/palette';
+import { CHAPTER_PALETTES, type MutableChapterPalette } from '@/scene/world/palette';
 
 export interface TerrainWorld {
   group: WorldGroup;
@@ -11,6 +11,7 @@ export interface TerrainWorld {
     speed: number,
     chapter: EnvironmentChapter,
     routeProgress: number,
+    palette?: Readonly<MutableChapterPalette>,
   ): void;
 }
 
@@ -131,14 +132,19 @@ export function createTerrain(
 
   return {
     group,
-    update(distance, speed, chapter, routeProgress) {
+    update(distance, speed, chapter, routeProgress, palette) {
-      const palette = CHAPTER_PALETTES[chapter];
+      const chapterPalette = CHAPTER_PALETTES[chapter];
       uniforms.uDistance.value = finiteOrZero(distance);
       uniforms.uSpeed.value = clamp01(speed);
       uniforms.uRouteProgress.value = clamp01(routeProgress);
-      uniforms.uTerrainEnergy.value = palette.terrainEnergy;
+      uniforms.uTerrainEnergy.value = palette?.terrainEnergy ?? chapterPalette.terrainEnergy;
-      lowColor.setHex(palette.terrainLow);
+      if (palette) {
-      highColor.setHex(palette.terrainHigh);
+        lowColor.copy(palette.terrainLow);
+        highColor.copy(palette.terrainHigh);
+      } else {
+        lowColor.setHex(chapterPalette.terrainLow);
+        highColor.setHex(chapterPalette.terrainHigh);
+      }
     },
   };
 }

src/styles/world.css

@@ -29,23 +29,83 @@
   object-fit: cover;
   background:
     radial-gradient(
-      circle at 50% 53%,
+      ellipse at 42% 89%,
-      rgb(247 105 115 / 82%) 0 7%,
+      rgb(255 45 85 / 72%) 0 0.65%,
-      transparent 7.3%
+      rgb(255 45 85 / 20%) 0.9% 2.6%,
+      transparent 4.8%
+    ),
+    radial-gradient(
+      ellipse at 58% 89%,
+      rgb(255 45 85 / 72%) 0 0.65%,
+      rgb(255 45 85 / 20%) 0.9% 2.6%,
+      transparent 4.8%
+    ),
+    linear-gradient(
+      166deg,
+      transparent 0 67%,
+      rgb(12 21 31 / 98%) 67.2% 76%,
+      transparent 76.2%
+    ),
+    linear-gradient(
+      194deg,
+      transparent 0 67%,
+      rgb(12 21 31 / 98%) 67.2% 76%,
+      transparent 76.2%
+    ),
+    radial-gradient(
+      ellipse at 50% 91%,
+      rgb(5 9 15 / 100%) 0 13%,
+      transparent 13.4%
+    ),
+    radial-gradient(
+      ellipse at 50% 55.8%,
+      transparent 0 4.8%,
+      rgb(4 8 20 / 88%) 5% 5.35%,
+      transparent 5.55%
+    ),
+    radial-gradient(
+      ellipse at 50% 54.6%,
+      rgb(244 173 103 / 92%) 0 6.7%,
+      rgb(199 75 145 / 65%) 7.1% 9.8%,
+      transparent 14%
+    ),
+    repeating-linear-gradient(
+      0deg,
+      transparent 0 5.2%,
+      rgb(4 8 20 / 88%) 5.3% 5.65%,
+      transparent 5.75% 7.2%
     ),
     linear-gradient(
       165deg,
-      transparent 0 60%,
+      transparent 0 55%,
-      rgb(73 198 215 / 34%) 60.2% 60.5%,
+      rgb(120 216 229 / 54%) 55.12% 55.32%,
-      transparent 60.7%
+      transparent 55.5%
     ),
     linear-gradient(
       195deg,
-      transparent 0 60%,
+      transparent 0 55%,
-      rgb(73 198 215 / 34%) 60.2% 60.5%,
+      rgb(120 216 229 / 54%) 55.12% 55.32%,
-      transparent 60.7%
+      transparent 55.5%
     ),
-    linear-gradient(180deg, #050817 0 48%, #24142c 67%, #080c17 100%);
+    conic-gradient(
+      from 167deg at 50% 55%,
+      rgb(5 9 17 / 96%) 0 12deg,
+      transparent 12.4deg 335.6deg,
+      rgb(5 9 17 / 96%) 336deg 360deg
+    ),
+    repeating-linear-gradient(
+      0deg,
+      transparent 0 6.5%,
+      rgb(73 198 215 / 14%) 6.65% 6.8%,
+      transparent 6.95% 9.5%
+    ),
+    radial-gradient(
+      ellipse at 50% 62%,
+      rgb(131 41 109 / 42%) 0,
+      transparent 48%
+    ),
+    linear-gradient(180deg, #030713 0 38%, #0c1025 54%, #26162e 69%, #050a14 100%);
+  background-size: cover;
 }
 
 .journey-canvas {
@@ -276,13 +336,7 @@
 
 @media (prefers-reduced-motion: reduce) {
   .journey-poster {
-    background:
+    filter: saturate(0.86) brightness(0.92);
-      radial-gradient(
-        circle at 50% 53%,
-        rgb(247 105 115 / 48%) 0 7%,
-        transparent 7.3%
-      ),
-      linear-gradient(180deg, #050817 0 48%, #24142c 67%, #080c17 100%);
   }
 }
 

tests/browser/journey-integration.spec.ts

@@ -22,6 +22,13 @@ test('keeps navigation, HUD, progress, chapter, and arrival on the same next-fra
   page,
   distUrl,
 }) => {
+  const graphicsErrors: string[] = [];
+  page.on('console', (message) => {
+    if (
+      message.type() === 'error'
+      && /THREE\.WebGLProgram|Shader Error|VALIDATE_STATUS/iu.test(message.text())
+    ) graphicsErrors.push(message.text());
+  });
   await page.goto(distUrl, { waitUntil: 'domcontentloaded' });
   await expect(page.locator('.journey-world')).toHaveAttribute('data-scene-state', /running|failed|static/u);
   const chapterColors: string[] = [];
@@ -60,16 +67,13 @@ test('keeps navigation, HUD, progress, chapter, and arrival on the same next-fra
 
   const instrumentation = await readSceneInstrumentation(page);
   expect(instrumentation.maximumCanvasCount).toBeLessThanOrEqual(1);
-  const expectedChapterColors = (page.viewportSize()?.width ?? 0) < 768
+  const chapterEnergy = chapterColors.map(colorEnergy);
-    ? [
+  for (let index = 1; index < chapterEnergy.length; index += 1) {
-        '#040713', '#040713', '#060918', '#080b1d',
+    expect(chapterEnergy[index]).toBeGreaterThanOrEqual(chapterEnergy[index - 1] ?? 0);
-        '#0d1025', '#0d1025', '#18152c', '#2b2035',
+  }
-      ]
+  expect(chapterEnergy.at(-1)).toBeGreaterThan(chapterEnergy[0] ?? 0);
-    : [
+  expect(new Set(chapterColors).size).toBeGreaterThanOrEqual(4);
-        '#000102', '#000102', '#000102', '#010103',
+  expect(graphicsErrors).toEqual([]);
-        '#010105', '#010105', '#020206', '#060409',
-      ];
-  expect(chapterColors).toEqual(expectedChapterColors);
 });
 
 test('draws only the independently eligible next roadside sign during passive forward travel', async ({
@@ -99,3 +103,8 @@ test('draws only the independently eligible next roadside sign during passive fo
   const labels = (await readSceneInstrumentation(page)).routeLabelsDrawn;
   expect([...new Set(labels)]).toEqual([oracle.expectedLabel]);
 });
+
+function colorEnergy(color: string): number {
+  const value = Number.parseInt(color.slice(1), 16);
+  return ((value >> 16) & 0xff) + ((value >> 8) & 0xff) + (value & 0xff);
+}

tests/unit/scene-resources.test.ts

@@ -160,8 +160,9 @@ describe('scene render quality', () => {
       roadSegments: 192,
       terrainSegments: 96,
       terrainOctaves: 3,
-      particleCount: 384,
+      starCount: 384,
       streakCount: 48,
+      postScale: 1,
       postEffects: true,
     });
     expect(medium).toEqual({
@@ -169,8 +170,9 @@ describe('scene render quality', () => {
       roadSegments: 144,
       terrainSegments: 64,
       terrainOctaves: 2,
-      particleCount: 192,
+      starCount: 192,
       streakCount: 28,
+      postScale: 0.7,
       postEffects: true,
     });
     expect(low).toEqual({
@@ -178,8 +180,9 @@ describe('scene render quality', () => {
       roadSegments: 96,
       terrainSegments: 32,
       terrainOctaves: 1,
-      particleCount: 64,
+      starCount: 64,
       streakCount: 12,
+      postScale: 0,
       postEffects: false,
     });
   });

tests/unit/scroll-drive-controller.test.ts

@@ -100,7 +100,7 @@ describe('scroll drive controller', () => {
     expect(snapshot.driveSpeed).toBeCloseTo(0.9490152503018645, 14);
   });
 
-  it('resets transient velocity and establishes a baseline after a gap over 250 ms', () => {
+  it('resets transient velocity and establishes a baseline after a stationary gap over 250 ms', () => {
     const controller = createScrollDriveController();
     controller.sample({ scrollY: 0, now: 0, maxScrollY: 1000 });
     controller.sample({ scrollY: 500, now: 100, maxScrollY: 1000 });
@@ -115,6 +115,19 @@ describe('scroll drive controller', () => {
     expect(controller.sample({ scrollY: 600, now: 451, maxScrollY: 1000 }).direction).toBe(1);
   });
 
+  it('preserves signed movement while dropping acceleration on the first delayed sample', () => {
+    const controller = createScrollDriveController();
+    controller.sample({ scrollY: 0, now: 0, maxScrollY: 1000 });
+
+    expect(controller.sample({ scrollY: 500, now: 351, maxScrollY: 1000 })).toEqual({
+      scrollY: 500,
+      routeProgress: 0.5,
+      direction: 1,
+      acceleration: 0,
+      driveSpeed: 0.18,
+    });
+  });
+
   it.each([
     ['downward', 0, 1000, 1],
     ['upward', 1000, 0, -1],

tests/unit/world-models.test.ts

@@ -1,4 +1,4 @@
-import { describe, expect, it } from 'vitest';
+import { describe, expect, it, vi } from 'vitest';
 import * as THREE from 'three';
 import type { EnvironmentChapter } from '@/journey/types';
 import { renderQualityFor } from '@/scene/render-quality';
@@ -10,6 +10,9 @@ import {
 } from '@/scene/world/palette';
 import { createRoad } from '@/scene/world/road';
 import { createTerrain } from '@/scene/world/terrain';
+import { createSun } from '@/scene/world/sun';
+import { createAtmosphere } from '@/scene/world/atmosphere';
+import { createPostProcessor } from '@/scene/post-processing';
 
 describe('procedural world models', () => {
   it('scales geometry and atmosphere work monotonically by live quality tier', () => {
@@ -132,6 +135,99 @@ describe('procedural world models', () => {
     expect(target.warmth).toBeGreaterThan(CHAPTER_PALETTES['deep-night'].warmth);
     expect(target.warmth).toBeLessThan(CHAPTER_PALETTES.destination.warmth);
   });
+
+  it('renders the sun as a scan-banded disc with a separately owned halo', () => {
+    const resources = new SceneResourceBag();
+    const sun = createSun(resources);
+    const disc = sun.group.getObjectByName('sun-disc') as ShaderRenderable;
+    const halo = sun.group.getObjectByName('sun-halo');
+
+    expect(disc).toBeInstanceOf(THREE.Mesh);
+    expect(halo).toBeInstanceOf(THREE.Sprite);
+    expect(disc.material.uniforms).toMatchObject({
+      uScanBands: { value: 14 },
+      uWarmth: { value: CHAPTER_PALETTES['deep-night'].warmth },
+    });
+    expect(disc.material.fragmentShader).toContain('scanBand');
+    expect(resources.snapshot().owned.texture).toBe(1);
+
+    const palette = createMutableChapterPalette('destination');
+    sun.update(palette, 1);
+    expect(disc.material.uniforms.uWarmth?.value).toBe(1);
+    expect(disc.material.uniforms.uRouteProgress?.value).toBe(1);
+    resources.dispose();
+  });
+
+  it('builds deterministic stars, haze layers, and quality-capped speed streaks', () => {
+    const highResources = new SceneResourceBag();
+    const lowResources = new SceneResourceBag();
+    const highQuality = renderQualityFor('high', 1, false);
+    const lowQuality = renderQualityFor('low', 1, true);
+    const high = createAtmosphere(highResources, highQuality);
+    const low = createAtmosphere(lowResources, lowQuality);
+    const highStars = high.group.getObjectByName('atmosphere-stars') as ShaderRenderable;
+    const lowStars = low.group.getObjectByName('atmosphere-stars') as ShaderRenderable;
+    const highStreaks = high.group.getObjectByName('atmosphere-streaks') as ShaderRenderable;
+    const lowStreaks = low.group.getObjectByName('atmosphere-streaks') as ShaderRenderable;
+
+    expect(highStars.geometry.getAttribute('position').count).toBe(highQuality.starCount);
+    expect(lowStars.geometry.getAttribute('position').count).toBe(lowQuality.starCount);
+    expect(highStreaks.geometry.getAttribute('position').count).toBe(highQuality.streakCount * 2);
+    expect(lowStreaks.geometry.getAttribute('position').count).toBe(lowQuality.streakCount * 2);
+    expect(high.group.getObjectByName('horizon-haze-near')).toBeInstanceOf(THREE.Mesh);
+    expect(high.group.getObjectByName('horizon-haze-far')).toBeInstanceOf(THREE.Mesh);
+
+    const highStarPositions = Array.from(highStars.geometry.getAttribute('position').array);
+    const secondResources = new SceneResourceBag();
+    const secondHigh = createAtmosphere(secondResources, highQuality);
+    const secondStars = secondHigh.group.getObjectByName('atmosphere-stars') as ShaderRenderable;
+    expect(Array.from(secondStars.geometry.getAttribute('position').array)).toEqual(highStarPositions);
+
+    const palette = createMutableChapterPalette('builds');
+    const before = highResources.snapshot();
+    for (let index = 0; index < 300; index += 1) {
+      high.update(index, 0.7, 0.8, palette);
+    }
+    expect(highResources.snapshot()).toEqual(before);
+    expect(highStreaks.material.uniforms.uAcceleration?.value).toBe(0.8);
+    expect(highStreaks.material.uniforms.uVisibility?.value).toBeGreaterThan(0);
+
+    highResources.dispose();
+    lowResources.dispose();
+    secondResources.dispose();
+  });
+
+  it('disposes a composer and its passes exactly once', () => {
+    const resources = new SceneResourceBag();
+    const composer = {
+      addPass: vi.fn(),
+      setPixelRatio: vi.fn(),
+      setSize: vi.fn(),
+      render: vi.fn(),
+      dispose: vi.fn(),
+    };
+    const renderPass = { scene: null, camera: null, setSize: vi.fn(), dispose: vi.fn() };
+    const bloomPass = { setSize: vi.fn(), dispose: vi.fn() };
+    const processor = createPostProcessor(resources, {}, {
+      createComposer: () => composer,
+      createRenderPass: () => renderPass,
+      createBloomPass: () => bloomPass,
+    });
+
+    processor.resize(1_200, 800, 1.25);
+    processor.render({}, {});
+    processor.dispose();
+    processor.dispose();
+    resources.dispose();
+
+    expect(composer.addPass).toHaveBeenCalledTimes(2);
+    expect(composer.setPixelRatio).toHaveBeenCalledWith(1.25);
+    expect(composer.setSize).toHaveBeenCalledWith(1_200, 800);
+    expect(composer.render).toHaveBeenCalledOnce();
+    expect(renderPass.dispose).toHaveBeenCalledOnce();
+    expect(bloomPass.dispose).toHaveBeenCalledOnce();
+    expect(composer.dispose).toHaveBeenCalledOnce();
+  });
 });
 
 function paletteSnapshot(palette: ReturnType<typeof createMutableChapterPalette>) {