Three.js WebGL/WebGPU Development

Overview

Three.js is the industry-standard JavaScript library for creating 3D graphics in web browsers using WebGL and WebGPU. This skill provides comprehensive guidance for building performant, interactive 3D experiences including scenes, cameras, renderers, geometries, materials, lights, textures, and animations.

Core Concepts

Scene Graph Architecture

Three.js uses a hierarchical scene graph where all 3D objects are organized in a tree structure:

Scene ├── Camera ├── Lights │ ├── AmbientLight │ ├── DirectionalLight │ └── PointLight ├── Meshes │ ├── Mesh (Geometry + Material) │ └── InstancedMesh └── Groups

Essential Components

Every Three.js application requires these core elements:

• Scene: Container for all 3D objects

• Camera: Defines the viewing perspective

• Renderer: Draws the scene to canvas (WebGL or WebGPU)

• Geometry: Defines the shape of objects

• Material: Defines the surface appearance

• Mesh: Combines geometry and material

Quick Start Pattern

Basic Scene Setup

import * as THREE from 'three'; import { OrbitControls } from 'three/addons/controls/OrbitControls.js';

// Scene, Camera, Renderer const scene = new THREE.Scene(); scene.background = new THREE.Color(0x333333);

const camera = new THREE.PerspectiveCamera( 75, // FOV window.innerWidth / window.innerHeight, // Aspect ratio 0.1, // Near clipping plane 1000 // Far clipping plane ); camera.position.set(0, 2, 5);

const renderer = new THREE.WebGLRenderer({ antialias: true }); renderer.setSize(window.innerWidth, window.innerHeight); renderer.setPixelRatio(window.devicePixelRatio); renderer.shadowMap.enabled = true; document.body.appendChild(renderer.domElement);

// Lighting const ambientLight = new THREE.AmbientLight(0xffffff, 0.5); scene.add(ambientLight);

const directionalLight = new THREE.DirectionalLight(0xffffff, 1); directionalLight.position.set(5, 10, 7.5); directionalLight.castShadow = true; scene.add(directionalLight);

// Controls const controls = new OrbitControls(camera, renderer.domElement); controls.enableDamping = true; controls.dampingFactor = 0.05;

// Animation Loop function animate() { requestAnimationFrame(animate); controls.update(); renderer.render(scene, camera); }

animate();

// Handle Resize window.addEventListener('resize', () => { camera.aspect = window.innerWidth / window.innerHeight; camera.updateProjectionMatrix(); renderer.setSize(window.innerWidth, window.innerHeight); });

WebGPU Setup (Modern Alternative)

import * as THREE from 'three/webgpu';

const renderer = new THREE.WebGPURenderer({ antialias: true }); renderer.setPixelRatio(window.devicePixelRatio); renderer.setSize(window.innerWidth, window.innerHeight); renderer.setAnimationLoop(animate); renderer.toneMapping = THREE.LinearToneMapping; renderer.toneMappingExposure = 1; document.body.appendChild(renderer.domElement);

Common Patterns

1. Creating Meshes with Materials

// Basic Mesh const geometry = new THREE.BoxGeometry(1, 1, 1); const material = new THREE.MeshStandardMaterial({ color: 0x00ff00, roughness: 0.5, metalness: 0.5 }); const cube = new THREE.Mesh(geometry, material); scene.add(cube);

// Textured Mesh const loader = new THREE.TextureLoader(); const texture = loader.load('texture.jpg'); texture.colorSpace = THREE.SRGBColorSpace;

const texturedMaterial = new THREE.MeshStandardMaterial({ map: texture }); const mesh = new THREE.Mesh(geometry, texturedMaterial); scene.add(mesh);

2. Lighting Strategies

// Three-Point Lighting Setup function setupThreePointLight(scene) { // Key Light (Main) const keyLight = new THREE.DirectionalLight(0xffffff, 3); keyLight.position.set(5, 10, 7.5); keyLight.castShadow = true; scene.add(keyLight);

// Fill Light (Softens shadows) const fillLight = new THREE.DirectionalLight(0xffffff, 1); fillLight.position.set(-5, 5, -5); scene.add(fillLight);

// Rim Light (Edge definition) const rimLight = new THREE.DirectionalLight(0xffffff, 0.5); rimLight.position.set(0, 5, -10); scene.add(rimLight);

// Ambient (Base illumination) const ambient = new THREE.AmbientLight(0x404040, 0.5); scene.add(ambient); }

// Physical Light (Realistic) const bulbLight = new THREE.PointLight(0xffee88, 1, 100, 2); bulbLight.power = 1700; // Lumens (100W bulb equivalent) bulbLight.castShadow = true; scene.add(bulbLight);

// Hemisphere Light (Sky + Ground) const hemiLight = new THREE.HemisphereLight( 0xddeeff, // Sky color 0x0f0e0d, // Ground color 0.02 ); scene.add(hemiLight);

3. Instanced Geometry (Performance)

// For rendering thousands of similar objects efficiently const geometry = new THREE.SphereGeometry(0.1, 16, 16); const material = new THREE.MeshStandardMaterial({ color: 0xff0000 }); const instancedMesh = new THREE.InstancedMesh(geometry, material, 1000);

const matrix = new THREE.Matrix4(); const color = new THREE.Color();

for (let i = 0; i < 1000; i++) { matrix.setPosition( Math.random() * 10 - 5, Math.random() * 10 - 5, Math.random() * 10 - 5 ); instancedMesh.setMatrixAt(i, matrix); instancedMesh.setColorAt(i, color.setHex(Math.random() * 0xffffff)); }

instancedMesh.instanceMatrix.needsUpdate = true; scene.add(instancedMesh);

4. Loading 3D Models (glTF)

import { GLTFLoader } from 'three/addons/loaders/GLTFLoader.js'; import { DRACOLoader } from 'three/addons/loaders/DRACOLoader.js';

// Setup loaders const dracoLoader = new DRACOLoader(); dracoLoader.setDecoderPath('/draco/');

const gltfLoader = new GLTFLoader(); gltfLoader.setDRACOLoader(dracoLoader);

// Load model gltfLoader.load('model.glb', (gltf) => { const model = gltf.scene;

// Enable shadows model.traverse((child) => { if (child.isMesh) { child.castShadow = true; child.receiveShadow = true; } });

scene.add(model);

// Handle animations if (gltf.animations.length > 0) { const mixer = new THREE.AnimationMixer(model); const action = mixer.clipAction(gltf.animations[0]); action.play();

// In animation loop:
// mixer.update(deltaTime);

} });

5. Shadow Configuration

// Enable shadows on renderer renderer.shadowMap.enabled = true; renderer.shadowMap.type = THREE.PCFSoftShadowMap; // or VSMShadowMap

// Configure light shadows directionalLight.castShadow = true; directionalLight.shadow.mapSize.width = 2048; directionalLight.shadow.mapSize.height = 2048; directionalLight.shadow.camera.near = 0.5; directionalLight.shadow.camera.far = 50; directionalLight.shadow.camera.left = -10; directionalLight.shadow.camera.right = 10; directionalLight.shadow.camera.top = 10; directionalLight.shadow.camera.bottom = -10; directionalLight.shadow.radius = 4; directionalLight.shadow.blurSamples = 8;

// Objects casting/receiving shadows mesh.castShadow = true; mesh.receiveShadow = true;

6. Raycasting (Interaction)

const raycaster = new THREE.Raycaster(); const mouse = new THREE.Vector2();

function onMouseClick(event) { mouse.x = (event.clientX / window.innerWidth) * 2 - 1; mouse.y = -(event.clientY / window.innerHeight) * 2 + 1;

raycaster.setFromCamera(mouse, camera); const intersects = raycaster.intersectObjects(scene.children, true);

if (intersects.length > 0) { const object = intersects[0].object; object.material.color.set(0xff0000); } }

window.addEventListener('click', onMouseClick);

Integration Patterns

With GSAP for Animation

import gsap from 'gsap';

// Animate camera gsap.to(camera.position, { x: 5, y: 3, z: 10, duration: 2, ease: "power2.inOut", onUpdate: () => { camera.lookAt(scene.position); } });

// Animate mesh properties gsap.to(mesh.rotation, { y: Math.PI * 2, duration: 3, repeat: -1, ease: "none" });

With React (see react-three-fiber skill)

// Three.js integrates naturally with React Three Fiber // Use the react-three-fiber skill for React integration patterns

With Post-Processing

import { EffectComposer } from 'three/addons/postprocessing/EffectComposer.js'; import { RenderPass } from 'three/addons/postprocessing/RenderPass.js'; import { UnrealBloomPass } from 'three/addons/postprocessing/UnrealBloomPass.js';

const composer = new EffectComposer(renderer); composer.addPass(new RenderPass(scene, camera));

const bloomPass = new UnrealBloomPass( new THREE.Vector2(window.innerWidth, window.innerHeight), 1.5, // strength 0.4, // radius 0.85 // threshold ); composer.addPass(bloomPass);

// In animation loop: composer.render();

Performance Optimization

1. Geometry Reuse

// Bad: Creates new geometry for each mesh for (let i = 0; i < 100; i++) { const geometry = new THREE.BoxGeometry(1, 1, 1); const mesh = new THREE.Mesh(geometry, material); scene.add(mesh); }

// Good: Reuse geometry const sharedGeometry = new THREE.BoxGeometry(1, 1, 1); for (let i = 0; i < 100; i++) { const mesh = new THREE.Mesh(sharedGeometry, material); scene.add(mesh); }

2. Use InstancedMesh for Repeated Objects

For hundreds/thousands of identical objects, use InstancedMesh (see pattern above).

3. Texture Optimization

// Compress textures texture.generateMipmaps = true; texture.minFilter = THREE.LinearMipmapLinearFilter; texture.magFilter = THREE.LinearFilter;

// Use power-of-two dimensions (512, 1024, 2048) // Consider texture atlases for multiple small textures

4. Level of Detail (LOD)

const lod = new THREE.LOD(); lod.addLevel(highDetailMesh, 0); // 0-50 units lod.addLevel(mediumDetailMesh, 50); // 50-100 units lod.addLevel(lowDetailMesh, 100); // 100+ units scene.add(lod);

5. Frustum Culling

Three.js automatically culls objects outside the camera's view. Ensure objects have correct bounding spheres:

mesh.geometry.computeBoundingSphere();

6. Dispose Resources

function disposeScene() { scene.traverse((object) => { if (object.geometry) object.geometry.dispose(); if (object.material) { if (Array.isArray(object.material)) { object.material.forEach(material => material.dispose()); } else { object.material.dispose(); } } }); renderer.dispose(); }

Best Practices

1. Use Animation Clocks for Consistent Timing

const clock = new THREE.Clock();

function animate() { const deltaTime = clock.getDelta(); const elapsedTime = clock.getElapsedTime();

// Use deltaTime for frame-independent animations mesh.rotation.y += deltaTime * Math.PI * 0.5; // 90° per second

renderer.render(scene, camera); }

2. Camera Setup Guidelines

• FOV: 45-75° for most applications

• Near plane: As far as possible (avoid z-fighting)

• Far plane: As close as possible (precision)

• Aspect ratio: Always match canvas dimensions

3. Material Selection

• MeshBasicMaterial: Unlit, flat colors (debugging, UI)

• MeshLambertMaterial: Cheap diffuse lighting (mobile)

• MeshPhongMaterial: Specular highlights (older standard)

• MeshStandardMaterial: PBR, realistic (recommended)

• MeshPhysicalMaterial: Advanced PBR (clearcoat, transmission)

4. Coordinate System

• Three.js uses right-handed coordinate system

• +Y is up, +Z is toward camera, +X is right

• Rotations use radians (Math.PI = 180°)

5. Scene Organization

// Group related objects const building = new THREE.Group(); building.add(walls, roof, windows); scene.add(building);

// Use meaningful names mesh.name = 'player-character'; const found = scene.getObjectByName('player-character');

Common Pitfalls

1. Not Updating Aspect Ratio on Resize

Always update camera aspect ratio and projection matrix when window resizes.

2. Creating New Objects in Animation Loop

// Bad: Memory leak function animate() { const geometry = new THREE.BoxGeometry(); // Created every frame! // ... }

// Good: Create once outside loop const geometry = new THREE.BoxGeometry(); function animate() { // Reuse geometry }

3. Forgetting to Enable Shadows

Remember to enable shadows on renderer, lights, and objects.

4. Z-Fighting (Flickering)

• Increase near plane distance

• Decrease far plane distance

• Avoid overlapping coplanar surfaces

• Use material.polygonOffset = true with material.polygonOffsetFactor

5. Color Space Issues

// Always set color space for textures texture.colorSpace = THREE.SRGBColorSpace;

// Set renderer output encoding renderer.outputColorSpace = THREE.SRGBColorSpace;

6. Not Disposing Resources

Always call .dispose() on geometries, materials, textures, and renderers when no longer needed.

Resources

This skill includes bundled resources to accelerate Three.js development:

references/

• api_reference.md : Quick API reference for core classes (Scene, Camera, Renderer, etc.)

• materials_guide.md : Comprehensive material types and properties

• optimization_checklist.md : Performance optimization strategies

scripts/

• setup_scene.py : Generate boilerplate Three.js scene setup code

• texture_optimizer.py : Batch optimize textures for web (resize, compress)

• gltf_validator.py : Validate glTF models before use

assets/

• starter_scene/ : Complete HTML/JS boilerplate project

• shaders/ : Custom GLSL shader examples (vertex, fragment)

• hdri/ : Environment maps for PBR lighting

• draco/ : DRACO decoder for compressed models

Advanced Topics

Custom Shaders (GLSL)

const material = new THREE.ShaderMaterial({ uniforms: { uTime: { value: 0.0 }, uColor: { value: new THREE.Color(0x00ff00) } }, vertexShader: varying vec2 vUv; void main() { vUv = uv; gl_Position = projectionMatrix * modelViewMatrix * vec4(position, 1.0); } , fragmentShader: uniform float uTime; uniform vec3 uColor; varying vec2 vUv; void main() { gl_FragColor = vec4(uColor * vUv.x, 1.0); } });

Render Targets (Render-to-Texture)

const renderTarget = new THREE.WebGLRenderTarget(512, 512);

// Render scene to texture renderer.setRenderTarget(renderTarget); renderer.render(scene, camera); renderer.setRenderTarget(null);

// Use texture const material = new THREE.MeshBasicMaterial({ map: renderTarget.texture });

GPU Computation (GPGPU)

Use GPUComputationRenderer for particle simulations, cloth physics, etc.

When to Use This Skill

Use this skill when:

• Building interactive 3D web experiences

• Creating product configurators or visualizers

• Implementing WebGL/WebGPU rendering

• Working with 3D models, scenes, or animations

• Optimizing Three.js performance

• Integrating Three.js with other libraries (GSAP, React, etc.)

• Debugging Three.js rendering issues

For React integration, use the react-three-fiber skill. For animation, combine with the gsap-scrolltrigger skill. For UI animations, use the motion-framer skill.