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JavaScript library for creating and displaying animated 3D computer graphics in web browsers

Core Idea: Three.js is a cross-browser JavaScript library that abstracts WebGL complexity, providing a high-level API for creating and rendering 3D graphics in web applications with minimal code.

Key Elements

Core Components

• Scene: Container that holds all objects, lights, and cameras
• Camera: Defines the viewpoint (perspective, orthographic, etc.)
• Renderer: Draws the scene from camera perspective (WebGL, CSS3D, SVG)
• Meshes: 3D objects composed of geometry and materials
• Materials: Define object appearance (color, texture, shininess)
• Geometries: Define object shape (vertices, faces, normals)
• Lights: Illuminate the scene with various light types
• Loaders: Import 3D models and textures from external files

Rendering Pipeline

• Scene Graph: Hierarchical organization of 3D objects
• Animation Loop: Continuous rendering for dynamic content
• Shaders: GLSL programs for advanced visual effects
• Post-processing: Effects applied after rendering (bloom, DOF)
• WebGL Integration: Low-level communication with graphics hardware

Development Workflow

• Setup: Creating renderer, scene, camera, and animation loop
• Scene Construction: Adding meshes, lights, and other objects
• Material Configuration: Applying colors, textures, and lighting properties
• Animation: Implementing motion and transformations
• Interaction: Adding user controls and event handling
• Optimization: Improving performance for complex scenes

Implementation Examples

Basic Scene Setup

// Create a scene
const scene = new THREE.Scene();

// Create a camera
const camera = new THREE.PerspectiveCamera(
  75,                   // Field of view
  window.innerWidth / window.innerHeight, // Aspect ratio
  0.1,                  // Near clipping plane
  1000                  // Far clipping plane
);
camera.position.z = 5;  // Position camera

// Create a renderer
const renderer = new THREE.WebGLRenderer({ antialias: true });
renderer.setSize(window.innerWidth, window.innerHeight);
document.body.appendChild(renderer.domElement);

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

// Add lighting
const light = new THREE.AmbientLight(0x404040); // Soft white light
scene.add(light);
const directionalLight = new THREE.DirectionalLight(0xffffff, 0.5);
directionalLight.position.set(1, 1, 1);
scene.add(directionalLight);

// Animation loop
function animate() {
  requestAnimationFrame(animate);
  
  // Rotate the cube
  cube.rotation.x += 0.01;
  cube.rotation.y += 0.01;
  
  // Render the scene
  renderer.render(scene, camera);
}
animate();

Advanced Material Usage

// Standard physically-based material
const standardMaterial = new THREE.MeshStandardMaterial({
  color: 0x049ef4,
  roughness: 0.5,
  metalness: 0.7,
  envMap: environmentTexture,
  map: colorTexture,
  normalMap: normalTexture,
  aoMap: ambientOcclusionTexture,
  displacementMap: heightTexture,
  displacementScale: 0.2
});

// Creating a custom shader material
const customMaterial = new THREE.ShaderMaterial({
  uniforms: {
    time: { value: 1.0 },
    resolution: { value: new THREE.Vector2() }
  },
  vertexShader: document.getElementById('vertexShader').textContent,
  fragmentShader: document.getElementById('fragmentShader').textContent
});

Loading 3D Models

// GLTF loader example
const loader = new THREE.GLTFLoader();
loader.load(
  'models/scene.gltf',
  function(gltf) {
    // Model loaded successfully
    scene.add(gltf.scene);
    
    // Access animations
    const animations = gltf.animations;
    const mixer = new THREE.AnimationMixer(gltf.scene);
    const action = mixer.clipAction(animations[0]);
    action.play();
  },
  function(xhr) {
    // Loading progress
    console.log((xhr.loaded / xhr.total * 100) + '% loaded');
  },
  function(error) {
    // Error occurred
    console.error('An error happened', error);
  }
);

Integration Approaches

Web Applications

• Single-page Applications: 3D visualization embedded in React, Vue, or Angular
• WebXR: Virtual and augmented reality experiences
• Data Visualization: 3D charts and interactive data exploration
• Product Configurators: Interactive 3D product customization

Mobile Integration

• React Native: Using Three.js via Expo GL or react-native-webgl
• Progressive Web Apps: Responsive 3D content for mobile browsers
• WebView Integration: Embedding Three.js content in native applications
• Performance Considerations: Optimization for mobile GPUs and battery life

Game Development

• Game Mechanics: Physics, collision detection, input handling
• Level Design: Procedural generation, terrain systems
• Entity Management: Game object hierarchies and interactions
• Multiplayer: Network synchronization of 3D scenes
• UI Integration: Combining 3D world with 2D interface elements

Optimization Techniques

• Geometry Management:

  • Use BufferGeometry for better performance
  • Implement geometry instancing for repeated objects
  • Apply level-of-detail (LOD) for distance-based simplification

• Rendering Optimization:

  • Frustum culling to skip rendering unseen objects
  • Occlusion culling to avoid rendering hidden objects
  • Object pooling to reduce garbage collection

• Memory Management:

  • Proper disposal of geometries and materials
  • Texture compression and mipmapping
  • Shared materials and geometries

• Shader Optimization:

  • Custom shader simplification for mobile
  • Defer expensive calculations to vertex shader when possible
  • Use shader chunks for code reusability

Ecosystem and Extensions

• Official Extensions:

  • Controls (OrbitControls, FlyControls, etc.)
  • Effects (OutlineEffect, StereoEffect, etc.)
  • Exporters and importers for various 3D formats

• Community Addons:

  • Physics engines (Ammo.js, Cannon.js, Oimo.js)
  • Post-processing libraries
  • Animation frameworks
  • Particle systems

• Development Tools:

  • Three.js Editor for visual scene creation
  • Three.js Inspector for debugging
  • Performance analyzers (stats.js)

Connections

• Related Concepts: WebGL (underlying technology), 3D Graphics Fundamentals (theoretical basis), GLSL Shaders (extension point)
• Broader Context: Web Graphics Technologies (broader field), Browser-based Game Development (application area)
• Applications: Three.js in React Native (mobile implementation), Data Visualization (practical use)
• Components: Perlin Noise (used for procedural generation), 3D Asset Creation (content production)

References

1. Three.js official documentation (https://threejs.org/docs/)
2. "3D Graphics with Three.js" by various authors
3. "WebGL Programming Guide" for underlying concepts

#three-js #webgl #3d-graphics #javascript #web-development

Connections:

Sources:

• From: notJust․dev - Vibe Coding a 3D GAME in React Native and ThreeJS (with AI)