Three.js 自定义遮罩通道教程

自定义遮罩通道 ·Custom Mask· ▶ 在线运行案例

• 案例合集：三维可视化功能案例（threehub.cn）
• 开源仓库github地址：https://github.com/z2586300277/three-cesium-examples
• 400个案例代码:网盘链接

你将学到什么

• EffectComposer 多 Pass 后期处理管线
• OrbitControls 相机轨道交互
• 自定义 ShaderPass 调色/特效
• requestAnimationFrame渲染循环与resize自适应

效果说明

本案例演示自定义遮罩通道效果：原场景渲染后经 EffectComposer 叠加 Bloom/模糊等全屏后期；核心用到 EffectComposer、OrbitControls、自定义。建议先打开文首在线案例查看动态画面，再对照下方源码逐步理解。

核心概念

• Scene / Camera / WebGLRenderer构成最小渲染闭环；大场景可开logarithmicDepthBuffer缓解 Z-fighting。
• EffectComposer以多 Pass 链式渲染：RenderPass → 特效 Pass → 输出屏幕，替代直接renderer.render。
• OrbitControls提供轨道旋转/缩放；开启enableDamping后需在 animate 中controls.update()。

实现步骤

• 搭建 Scene、PerspectiveCamera、WebGLRenderer，挂载 canvas 并处理resize
• 定义 uniforms / onBeforeCompile 或 ShaderMaterial，编写 GLSL 与材质参数
• 组装 EffectComposer Pass 链，在 animate 中调用composer.render()
• 创建 OrbitControls（及 Raycaster 等交互控件，若源码包含）
• 在requestAnimationFrame循环中更新状态并 render（Cesium 为viewer.render或自动渲染）

• 代码要点

  import * as THREE from 'three'
  import { OrbitControls } from 'three/examples/jsm/controls/OrbitControls.js' import { ShaderPass } from 'three/examples/jsm/postprocessing/ShaderPass.js' import { EffectComposer } from 'three/examples/jsm/postprocessing/EffectComposer.js' import { RenderPass } from 'three/examples/jsm/postprocessing/RenderPass.js'
  class ScreenMaskPass extends ShaderPass {
  constructor() {
  super({
  name: 'ScreenMaskShader',
  uniforms: { tDiffuse: { value: null }, opacity: { value: 1.0 }, intensity: { value: 2.0 }, maskColor: { value: new THREE.Color(1, 1, 1) }, R: { value: 0.1 }, sr: { value: 1.2 } },
  vertexShader:varying vec2 vUv; void main() { vUv = uv; gl_Position = projectionMatrixmodelViewMatrixvec4( position, 1.0 ); },
  fragmentShader:uniform float opacity; uniform float intensity; uniform sampler2D tDiffuse; uniform vec3 maskColor; uniform float R; uniform float sr; varying vec2 vUv; void main() { // 阴影颜色 vec4 texel = texture2D( tDiffuse, vUv ); // 距离中心的距离 float dist = sqrt((vUv.x-0.5)(vUv.x-0.5)+(vUv.y-0.5)(vUv.y-0.5)); // 渐变, sr 是开始黑色参数 float rr = (sr - smoothstep(R, R + 0.5, dist)); // 叠加黑色 texel= vec4(maskColorrr * vec3(intensity,intensity,intensity), 1.0); gl_FragColor = opacity * texel; }
  })
  }
  }
  const box = document.getElementById('box')
  const scene = new THREE.Scene()
  const camera = new THREE.PerspectiveCamera(75, box.clientWidth / box.clientHeight, 0.1, 1000)
  camera.position.set(0, 2, 8)
  const renderer = new THREE.WebGLRenderer()
  renderer.setSize(box.clientWidth, box.clientHeight)
  box.appendChild(renderer.domElement)
  new OrbitControls(camera, renderer.domElement)
  const composer = new EffectComposer(renderer)
  const renderPass = new RenderPass(scene, camera)
  composer.addPass(renderPass)
  const screenMaskPass = new ScreenMaskPass()
  composer.addPass(screenMaskPass)
  scene.add(new THREE.AxesHelper(500), new THREE.GridHelper(500, 50))
  animate()
  function animate() {
  requestAnimationFrame(animate)
  composer.render()
  }
  window.onresize = () => {
  renderer.setSize(box.clientWidth, box.clientHeight)
  camera.aspect = box.clientWidth / box.clientHeight
  camera.updateProjectionMatrix()
  }
  // 文件地址 const urls = [0, 1, 2, 3, 4, 5].map(k => ('https://z2586300277.github.io/three-editor/dist/files/scene/skyBox0/' + (k + 1) + '.png'));
  const textureCube = new THREE.CubeTextureLoader().load(urls);
  scene.background = textureCube;

  完整源码：GitHub

  小结

  • 本文提供自定义遮罩通道完整 Three.js 源码与在线 Demo，建议先运行案例再改 uniform/参数做二次实验
  • 更多 Three.js 实战案例见 three-cesium-examples 合集 与 GitHub 开源仓库