Three.js 心教程

心 ·Heart Shader· ▶ 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

  • ShaderMaterial 自定义着色器实现核心视觉效果
  • EffectComposer 多 Pass 后期处理管线
  • UnrealBloomPass 辉光 Bloom 效果
  • OrbitControls 相机轨道交互
  • requestAnimationFrame渲染循环与resize自适应

效果说明

本案例演示效果:原场景渲染后经 EffectComposer 叠加 Bloom/模糊等全屏后期;核心用到 ShaderMaterial、EffectComposer、UnrealBloomPass。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。
  • ShaderMaterial通过uniforms+ 自定义 GLSL 控制逐像素/逐点效果;透明粒子常配合depthTest: false
  • 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)
  • 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 { UnrealBloomPass } from 'three/examples/jsm/postprocessing/UnrealBloomPass.js'; import { EffectComposer } from 'three/examples/jsm/postprocessing/EffectComposer.js'; import { RenderPass } from 'three/examples/jsm/postprocessing/RenderPass.js';

    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, 0, 20)

    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 bloomPass = new UnrealBloomPass(new THREE.Vector2(window.innerWidth, window.innerHeight), 5, 1.2, 0)

    composer.addPass(bloomPass);

    window.onresize = () => {

    renderer.setSize(box.clientWidth, box.clientHeight)

    camera.aspect = box.clientWidth / box.clientHeight

    camera.updateProjectionMatrix()

    }

    class HeartCurve extends THREE.Curve { constructor(scale = 1) { super(); this.scale = scale; }

    getPoint(a, optionalTarget = new THREE.Vector3()) { const t = aMath.PI2; const tx = 16 * Math.pow(Math.sin(t), 3); const ty = 13Math.cos(t) - 5Math.cos(2t) - 2Math.cos(3t) - Math.cos(4t); const tz = 0;

    return optionalTarget.set(tx, ty, tz).multiplyScalar(this.scale); } }

    const geometry = new THREE.TubeGeometry(new HeartCurve(0.5), 100, 0.1, 30, false);

    const vertexShader =varying vec2 vUv; void main(void) { vUv = uv; gl_Position = projectionMatrixmodelViewMatrixvec4(position, 1.0); }; const fragmentShader =varying vec2 vUv; uniform float uSpeed; uniform float uTime; uniform vec2 uFade; uniform vec3 uColor; uniform float uDirection; void main() { vec3 color =uColor; float s=0.0; float v=0.0; if(uDirection==1.0){ v=vUv.x; s=-uTime*uSpeed; }else{ v= -vUv.x; s= -uTime*uSpeed; } float d=mod( (v + s) ,1.0) ; if(d>uFade.y)discard; else{ float alpha = smoothstep(uFade.x, uFade.y, d); if (alpha < 0.0001) discard; gl_FragColor = vec4(color,alpha); } };

    const getMaterial = (uniforms) => { return new THREE.ShaderMaterial({ uniforms, vertexShader, fragmentShader, transparent: true }); }

    const material1 = getMaterial({ uColor: { value: new THREE.Color('pink') }, uTime: { value: 0 }, uDirection: { value: 1 }, uSpeed: { value: 1 }, uFade: { value: new THREE.Vector2(0, 0.5) }, uDirection: { value: 1 }, uSpeed: { value: 1 } })

    const material2 = getMaterial({ uColor: { value: new THREE.Color('#00BFFF') }, uTime: { value: 0.5 }, uDirection: { value: 1 }, uSpeed: { value: 1 }, uFade: { value: new THREE.Vector2(0, 0.5) }, uDirection: { value: 1 }, uSpeed: { value: 1 } })

    const mesh = new THREE.Mesh(geometry, material1) const mesh2 = new THREE.Mesh(geometry, material2)

    scene.add(mesh);

    scene.add(mesh2)

    animate()

    function animate() {

    material1.uniforms.uTime.value += 0.002 material2.uniforms.uTime.value += 0.002

    requestAnimationFrame(animate)

    renderer.render(scene, camera)

    composer.render();

    }

    完整源码:GitHub

    小结

    • 本文提供完整 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