Three.js 场景雪教程

场景雪 ·sceneSnowEffect· ▶ 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
• OrbitControls 相机轨道交互
• THREE.Points 粒子点渲染
• glTF/Draco 模型加载与优化
• BufferGeometry 自定义顶点/索引数据
• requestAnimationFrame渲染循环与resize自适应

效果说明

本案例演示场景雪效果：基于 WebGL 实现「场景雪」可视化效果，附完整可运行源码；核心用到 ShaderMaterial、OrbitControls、THREE.Points。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。
• OrbitControls提供轨道旋转/缩放；开启enableDamping后需在 animate 中controls.update()。
• THREE.Points将每个顶点渲染为可控大小的粒子；可用自定义 attribute（如u_index）驱动片元/顶点动画。

实现步骤

• 搭建 Scene、PerspectiveCamera、WebGLRenderer，挂载 canvas 并处理resize
• 异步加载模型 / 3D Tiles / GeoJSON 等资源并加入 scene 或 entities
• 定义 uniforms / onBeforeCompile 或 ShaderMaterial，编写 GLSL 与材质参数
• 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 Stats from 'three/examples/jsm/libs/stats.module.js'; import {GLTFLoader} from "three/examples/jsm/loaders/GLTFLoader.js"; import {OrbitControls} from 'three/examples/jsm/controls/OrbitControls.js' import {DRACOLoader} from "three/examples/jsm/loaders/DRACOLoader.js"; import {GUI} from "three/addons/libs/lil-gui.module.min.js" console.log('Three.js 版本:', THREE.REVISION); const gui = new GUI() const size = { width: window.innerWidth, height: window.innerHeight, maxX: 20, minX: -20, maxY: 20, minY: 0, maxZ: 20, minZ: -20 } const vertices = [] const offset = [] let particleCount=1000 const geometry = new THREE.BufferGeometry() for (let i = 0; i < particleCount; i++) { const x = 1000 * (Math.random() - 0.5) const y = 600 * Math.random() const z = 1000 * (Math.random() - 0.5)
  vertices.push(x, y, z) offset.push(Math.random() - 0.5, 0, Math.random() - 0.5) } geometry.setAttribute('position', new THREE.Float32BufferAttribute(vertices, 3)) /*纹理/ const texture = new THREE.TextureLoader().load(HOST + 'files/images/snow.png') const pointMesh = new THREE.Points( geometry, new THREE.PointsMaterial({ size: 5, depthTest: true, map: texture, transparent: true, blending: THREE.AdditiveBlending, opacity: 0.8, sizeAttenuation: true }) ) // 创建一个控制对象 const params = { snowEnabled: true, // 默认值为true snowAmount: 0.7 };
  //后处理管理对象 const postprocessing = {}
  // 添加GUI控制 const folder = gui.addFolder('调节参数'); // 添加checkbox folder.add(params, 'snowEnabled').name('启用雪效果').onChange((value) => { params.snowEnabled = value; }); folder.add(params, "snowAmount", 0, 1, 0.01).name('雪量').onChange((value) => { postprocessing.finalMaterial.uniforms.snowAmount.value = value; });
  // 初始化场景、相机、渲染器 const scene = new THREE.Scene(); const camera = new THREE.PerspectiveCamera(75, window.innerWidth / window.innerHeight, 0.1, 10000); camera.position.set(0, 100, 300); // 明确设置相机初始位置 camera.lookAt(0, 0, 0); // 看向场景中心 scene.add(camera); const renderer = new THREE.WebGLRenderer({ antialias: true, alpha: true, logarithmicDepthBuffer: true }); renderer.outputColorSpace = 'srgb' renderer.setSize(window.innerWidth, window.innerHeight); renderer.setClearColor(0x000000); document.body.appendChild(renderer.domElement);
  const ambientLight = new THREE.AmbientLight('#fff', 2); scene.add(ambientLight); scene.add(pointMesh); // 添加性能监控 const stats = new Stats(); document.body.appendChild(stats.dom); // 初始化控制器 const controls = new OrbitControls(camera, renderer.domElement); controls.enableDamping = true;
  const gltfLoader = new GLTFLoader() const dracoLoader = new DRACOLoader() dracoLoader.setDecoderPath(FILE_HOST + 'js/three/draco/') gltfLoader.setDRACOLoader(dracoLoader) //加载模型 使用私有对象存储带宽较低耐心等待一下 // "http://app.foxicle.xyz:9000/public-bucket/model/city/index.gltf" gltfLoader.load(FILE_HOST + 'models/modern_city.glb', (gltf) => { gltf.scene.scale.set(0.01, 0.01, 0.01); scene.add(gltf.scene) }, (event) => { const percentComplete = (event.loaded / event.total * 100).toFixed(2); console.log(模型加载进度: ${percentComplete}%); });
  initPostprocessing(window.innerWidth, window.innerHeight)
  function updatePoints(){ for (let i = 1; i < vertices.length; i += 3) { vertices[i] -= 0.5 vertices[i - 1] -= offset[i - 1] vertices[i + 1] -= offset[i + 1] if (vertices[i] < 0) { vertices[i] = 600 }
  if (vertices[i - 1] < size.minX || vertices[i - 1] > size.maxX) { offset[i - 1] = -offset[i - 1] }
  if (vertices[i + 1] < size.minZ || vertices[i + 1] > size.maxZ) { offset[i + 1] = -offset[i + 1] } }
  pointMesh.geometry.setAttribute('position', new THREE.Float32BufferAttribute(vertices, 3)) }
  // 动画渲染 function animate() { requestAnimationFrame(animate)
  if (params.snowEnabled) { pointMesh.visible=true updatePoints() scene.overrideMaterial = null //写入原场景渲染图 renderer.setRenderTarget(postprocessing.difusse) renderer.render(scene, camera) // //将定点数据 法相数据存入通道 scene.overrideMaterial = postprocessing.gBufferPass renderer.setRenderTarget(postprocessing.gBuffer) renderer.render(scene, camera) renderer.setRenderTarget(null) renderer.render(postprocessing.scene, postprocessing.camera); } else { pointMesh.visible=false scene.overrideMaterial = null renderer.setRenderTarget(null) renderer.render(scene, camera) } stats.update() controls.update() }
  animate();
  /**
  核心逻辑,备注:对场景中部分透明物体渲染存在错误,需要额外处理,这里主要是提供思路
  @param renderTargetWidth
  @param renderTargetHeight
  */ function initPostprocessing(renderTargetWidth, renderTargetHeight) { postprocessing.scene = new THREE.Scene(); postprocessing.camera = new THREE.OrthographicCamera(-1, 1, 1, -1, 0, 1); postprocessing.scene.add(postprocessing.camera); //漫射 postprocessing.difusse = new THREE.WebGLRenderTarget(renderTargetWidth, renderTargetHeight, { format: THREE.RGBAFormat, type: THREE.FloatType, colorSpace: THREE.SRGBColorSpace, depthBuffer: true, samples: 4, minFilter: THREE.NearestFilter, magFilter: THREE.NearestFilter, stencilBuffer: false, }) postprocessing.gBuffer = new THREE.WebGLRenderTarget(renderTargetWidth, renderTargetHeight, { format: THREE.RGBAFormat, // 使用 RGBAFormat 确保有 alpha 通道 type: THREE.FloatType, // 使用 FloatType 以确保存储精度 depthBuffer: true, // 确保有深度缓冲 samples: 4, count: 2 })
  // G-BUFFER 管线 postprocessing.gBufferPass = new THREE.ShaderMaterial({ vertexShader:out vec3 vNormal; out vec3 vWorldPosition; void main() { vNormal = normal; // 计算顶点的世界坐标，模型矩阵将顶点从模型空间转换到世界空间 vec4 worldPosition = modelMatrix * vec4(position, 1.0); vWorldPosition = worldPosition.xyz; gl_Position = projectionMatrixviewMatrixworldPosition; }, fragmentShader:in vec3 vNormal; in vec3 vWorldPosition; layout(location = 0) out vec4 gPosition; layout(location = 1) out vec4 gNormal; void main() { gPosition = vec4(vWorldPosition, 1.0); gNormal = normalize(vec4(vNormal, 1.0)); }, glslVersion: '300 es' })
  postprocessing.finalMaterial = new THREE.ShaderMaterial({ defines: { EMISSIVE: 10, }, vertexShader:out vec2 vUv; void main() { vUv = uv; gl_Position = projectionMatrixviewMatrixmodelMatrix * vec4(position, 1.0); }, fragmentShader:precision highp float; precision highp int; uniform sampler2D tPosition; uniform sampler2D tNormal; uniform sampler2D tDiffuse; uniform vec2 resolution; uniform float time; uniform vec3 uCameraPosition; uniform float snowAmount; uniform float snowNoise; uniform float snowEdge; in vec2 vUv; out vec4 fragColor; // 改进的噪声函数 float rand(vec2 co) { return fract(sin(dot(co.xy, vec2(12.9898, 78.233))) * 43758.5453); } float noise(vec2 p) { vec2 ip = floor(p); vec2 fp = fract(p); float a = rand(ip); float b = rand(ip + vec2(1.0, 0.0)); float c = rand(ip + vec2(0.0, 1.0)); float d = rand(ip + vec2(1.0, 1.0)); vec2 u = fpfp(3.0 - 2.0 * fp); return mix(a, b, u.x) + (c - a)u.y(1.0 - u.x) + (d - b)u.xu.y; } float fbm(vec2 p) { float total = 0.0; float amplitude = 1.0; for (int i = 0; i < 4; i++) { total += noise(p) * amplitude; p *= 2.0; amplitude *= 0.5; } return total; } void main() { // 从G-Buffer读取数据 vec3 position = texture(tPosition, vUv).rgb; vec3 normal = normalize(texture(tNormal, vUv).rgb); vec4 diffuseSample = texture(tDiffuse, vUv); vec3 diffuse = diffuseSample.rgb; if (diffuseSample.a<0.01) discard; // 计算积雪因子 - 基于法线Y分量 float snowFactor = max(0.0, dot(normal, vec3(0.0, 1.0, 0.0))); snowFactor = pow(snowFactor, 3.0);// 增强对比度 // 添加噪声效果 vec2 noiseCoord = position.xz0.5 + vec2(time0.05); float noiseVal = fbm(noiseCoord); snowFactor = clamp(snowFactor + (noiseVal - 0.5) * snowNoise, 0.0, 1.0); snowFactor *= snowAmount; // 边缘积雪增强 vec2 texelSize = 1.0 / resolution; float depthCenter = texture(tPosition, vUv).z; float depthRight = texture(tPosition, vUv + vec2(texelSize.x, 0.0)).z; float depthBottom = texture(tPosition, vUv + vec2(0.0, texelSize.y)).z; float depthDiff = max(abs(depthCenter - depthRight), abs(depthCenter - depthBottom)); snowFactor = max(snowFactor, smoothstep(0.0, 0.1, depthDiff) * snowEdge); // 雪的颜色 - 使用更纯的白色，减少蓝色调 vec3 snowColor = mix(vec3(0.95, 0.96, 0.98), vec3(1.0), noiseVal * 0.2); // 最终颜色混合 - 使用更激进的混合 vec3 finalColor = mix(diffuse, snowColor, smoothstep(0.3, 0.7, snowFactor)); // 修改高光效果 - 更柔和、更白的高光 if (snowFactor > 0.3) { vec3 lightDir = normalize(vec3(1.0, 1.0, 1.0)); vec3 viewDir = normalize(uCameraPosition - position); vec3 halfDir = normalize(lightDir + viewDir); float spec = pow(max(0.0, dot(normal, halfDir)), 32.0); // 使用白色高光，强度降低 finalColor += spec0.1vec3(1.0) * snowFactor; } // 提高整体亮度 finalColor = mix(finalColor, vec3(1.0), snowFactor * 0.3); fragColor = vec4(finalColor, 1.0); }, glslVersion: '300 es', uniforms: { tPosition: {value: postprocessing.gBuffer.textures[0]}, tNormal: {value: postprocessing.gBuffer.textures[1]}, tDiffuse: {value: postprocessing.difusse.texture}, resolution: {value: new THREE.Vector2(window.innerWidth, window.innerHeight)}, time: {value: 0}, uCameraPosition: {value: new THREE.Vector3()}, // 对应着色器中的重命名 snowAmount: {value: 0.7}, snowNoise: {value: 0.3}, snowEdge: {value: 0.5} }, }); postprocessing.quad = new THREE.Mesh( new THREE.PlaneGeometry(2.0, 2.0), postprocessing.finalMaterial ); postprocessing.scene.add(postprocessing.quad);
  }
  // 窗口大小调整 window.addEventListener('resize', onWindowResize, false);
  function onWindowResize() { camera.aspect = window.innerWidth / window.innerHeight; camera.updateProjectionMatrix(); renderer.setSize(window.innerWidth, window.innerHeight); }

  完整源码：GitHub

  小结

  • 本文提供场景雪完整 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