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name: threejs-fundamentals description: Three.js 场景设置、相机、渲染器、Object3D 层级结构、坐标系统。在设置 3D 场景、创建相机、配置渲染器、管理对象层级或处理变换时使用。 risk: unknown source: community

Three.js 基础

何时使用

• 你需要设置 Three.js 场景的核心结构。
• 任务涉及场景、相机、渲染器、变换、窗口大小调整处理或对象层级基础。
• 你需要在处理着色器或后处理等专业主题之前获得基础的 Three.js 指导。

快速开始

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);
});

核心类

Scene（场景）

所有 3D 对象、灯光和相机的容器。

const scene = new THREE.Scene();
scene.background = new THREE.Color(0x000000); // Solid color
scene.background = texture; // Skybox texture
scene.background = cubeTexture; // Cubemap
scene.environment = envMap; // Environment map for PBR
scene.fog = new THREE.Fog(0xffffff, 1, 100); // Linear fog
scene.fog = new THREE.FogExp2(0xffffff, 0.02); // Exponential fog

Cameras（相机）

PerspectiveCamera（透视相机） - 最常用，模拟人眼。

// PerspectiveCamera(fov, aspect, near, far)
const camera = new THREE.PerspectiveCamera(
  75, // Field of view (degrees)
  window.innerWidth / window.innerHeight, // Aspect ratio
  0.1, // Near clipping plane
  1000, // Far clipping plane
);

camera.position.set(0, 5, 10);
camera.lookAt(0, 0, 0);
camera.updateProjectionMatrix(); // Call after changing fov, aspect, near, far

OrthographicCamera（正交相机） - 无透视变形，适合 2D/等距视图。

// OrthographicCamera(left, right, top, bottom, near, far)
const aspect = window.innerWidth / window.innerHeight;
const frustumSize = 10;
const camera = new THREE.OrthographicCamera(
  (frustumSize * aspect) / -2,
  (frustumSize * aspect) / 2,
  frustumSize / 2,
  frustumSize / -2,
  0.1,
  1000,
);

ArrayCamera（阵列相机） - 多视口与子相机。

const cameras = [];
for (let i = 0; i < 4; i++) {
  const subcamera = new THREE.PerspectiveCamera(40, 1, 0.1, 100);
  subcamera.viewport = new THREE.Vector4(
    Math.floor(i % 2) * 0.5,
    Math.floor(i / 2) * 0.5,
    0.5,
    0.5,
  );
  cameras.push(subcamera);
}
const arrayCamera = new THREE.ArrayCamera(cameras);

CubeCamera（立方体相机） - 渲染反射用的环境贴图。

const cubeRenderTarget = new THREE.WebGLCubeRenderTarget(256);
const cubeCamera = new THREE.CubeCamera(0.1, 1000, cubeRenderTarget);
scene.add(cubeCamera);

// Use for reflections
material.envMap = cubeRenderTarget.texture;

// Update each frame (expensive!)
cubeCamera.position.copy(reflectiveMesh.position);
cubeCamera.update(renderer, scene);

WebGLRenderer（WebGL 渲染器）

const renderer = new THREE.WebGLRenderer({
  canvas: document.querySelector("#canvas"), // Optional existing canvas
  antialias: true, // Smooth edges
  alpha: true, // Transparent background
  powerPreference: "high-performance", // GPU hint
  preserveDrawingBuffer: true, // For screenshots
});

renderer.setSize(width, height);
renderer.setPixelRatio(Math.min(window.devicePixelRatio, 2));

// Tone mapping
renderer.toneMapping = THREE.ACESFilmicToneMapping;
renderer.toneMappingExposure = 1.0;

// Color space (Three.js r152+)
renderer.outputColorSpace = THREE.SRGBColorSpace;

// Shadows
renderer.shadowMap.enabled = true;
renderer.shadowMap.type = THREE.PCFSoftShadowMap;

// Clear color
renderer.setClearColor(0x000000, 1);

// Render
renderer.render(scene, camera);

Object3D

所有 3D 对象的基类。Mesh、Group、Light、Camera 都继承自 Object3D。

const obj = new THREE.Object3D();

// Transform
obj.position.set(x, y, z);
obj.rotation.set(rx, ry, rz);
obj.scale.set(sx, sy, sz);