Three.js Fundamentals
Quick Start
javascript
import * as THREE from "three";
// Create scene, camera, renderer
const scene = new THREE.Scene();
const camera = new THREE.PerspectiveCamera(
75,
window.innerWidth / window.innerHeight,
0.1,
1000,
);
const renderer = new THREE.WebGLRenderer({ antialias: true });
renderer.setSize(window.innerWidth, window.innerHeight);
renderer.setPixelRatio(Math.min(window.devicePixelRatio, 2));
document.body.appendChild(renderer.domElement);
// Add a mesh
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 light
scene.add(new THREE.AmbientLight(0xffffff, 0.5));
const dirLight = new THREE.DirectionalLight(0xffffff, 1);
dirLight.position.set(5, 5, 5);
scene.add(dirLight);
camera.position.z = 5;
// Animation loop
function animate() {
requestAnimationFrame(animate);
cube.rotation.x += 0.01;
cube.rotation.y += 0.01;
renderer.render(scene, camera);
}
animate();
// Handle resize
window.addEventListener("resize", () => {
camera.aspect = window.innerWidth / window.innerHeight;
camera.updateProjectionMatrix();
renderer.setSize(window.innerWidth, window.innerHeight);
});
Core Classes
Scene
javascript
const scene = new THREE.Scene(); scene.background = new THREE.Color(0x000000); scene.fog = new THREE.Fog(0xffffff, 1, 100);
Cameras
javascript
// PerspectiveCamera(fov, aspect, near, far) const camera = new THREE.PerspectiveCamera(75, window.innerWidth / window.innerHeight, 0.1, 1000); camera.position.set(0, 5, 10); camera.lookAt(0, 0, 0);
WebGLRenderer
javascript
const renderer = new THREE.WebGLRenderer({ antialias: true, alpha: true });
renderer.setSize(width, height);
renderer.setPixelRatio(Math.min(window.devicePixelRatio, 2));
renderer.shadowMap.enabled = true;
renderer.shadowMap.type = THREE.PCFSoftShadowMap;
renderer.toneMapping = THREE.ACESFilmicToneMapping;
renderer.outputColorSpace = THREE.SRGBColorSpace;
Object3D
javascript
obj.position.set(x, y, z);
obj.rotation.set(x, y, z);
obj.scale.set(x, y, z);
obj.add(child);
obj.remove(child);
obj.traverse((child) => { /* ... */ });
Math Utilities
Vector3
javascript
const v = new THREE.Vector3(x, y, z); v.add(v2); v.sub(v2); v.normalize(); v.lerp(target, alpha); v.length(); v.distanceTo(v2); v.dot(v2); v.cross(v2);
MathUtils
javascript
THREE.MathUtils.clamp(value, min, max); THREE.MathUtils.lerp(start, end, alpha); THREE.MathUtils.degToRad(degrees); THREE.MathUtils.randFloat(min, max);
Common Patterns
Clock for Animation
javascript
const clock = new THREE.Clock();
function animate() {
const delta = clock.getDelta();
mesh.rotation.y += delta * 0.5;
requestAnimationFrame(animate);
renderer.render(scene, camera);
}
Proper Cleanup
javascript
function dispose() {
mesh.geometry.dispose();
mesh.material.dispose();
scene.remove(mesh);
renderer.dispose();
}
See Also
- •
threejs-geometry- Geometry creation - •
threejs-materials- Material types - •
threejs-lighting- Light types and shadows