Three.js 城市线条教程-洪萨配资

城市线条 ·City Line· ▶ 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
FBXLoader 加载 FBX 城市/角色模型
EdgesGeometry 模型边线提取
requestAnimationFrame渲染循环与resize自适应

效果说明

本案例演示城市线条效果：基于 WebGL 实现「城市线条」可视化效果，附完整可运行源码；核心用到 ShaderMaterial、OrbitControls、FBXLoader。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()。

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 { OrbitControls } from 'three/examples/jsm/controls/OrbitControls.js' import { FBXLoader } from 'three/examples/jsm/loaders/FBXLoader.js'
class City {
constructor() { this.fbxLoader = new FBXLoader(); this.group = new THREE.Group(); this.clock = new THREE.Clock() this.surroundLineMaterial = null;// 定义包围线材质属性 this.time = { value: 0 }; this.startTime = { value: 0 }; this.startLength = { value: 2 } this.isStart = false;
this.fbxLoader.load(FILE_HOST + 'models/fbx/shanghai.FBX', (group) => {
this.group.add(group); group.traverse((child) => { // 设置城市建筑（mesh物体），材质基本颜色 if (child.name == 'CITY_UNTRIANGULATED') { const materials = Array.isArray(child.material) ? child.material : [child.material] materials.forEach((material) => { material.transparent = true; material.color.setStyle("#9370DB"); }) }
// 设置城市地面（mesh物体），材质基本颜色 if (child.name == 'LANDMASS') { const materials = Array.isArray(child.material) ? child.material : [child.material] materials.forEach((material) => { material.transparent = true; material.color.setStyle("#040912"); }) } })
this.init(); }); }
// 初始化城市类的实例 init() { this.isStart = true; // 城市渲染启动 this.clock.start() this.surroundLine(); }
// 创建包围线条效果 surroundLine() { let cityBuildings // 城市建筑群 this.group.traverse(child => { if (child.name !== 'CITY_UNTRIANGULATED') return cityBuildings = child })
const geometry = new THREE.EdgesGeometry(cityBuildings.geometry); const surroundLineMaterial = new THREE.ShaderMaterial({ transparent: true, uniforms: { uColor: { value: new THREE.Color('#FFF') } }, vertexShader:void main() { gl_Position = projectionMatrixmodelViewMatrixvec4(position, 1.0); }, fragmentShader:uniform vec3 uColor; void main() { gl_FragColor = vec4(uColor, 1); }});
const line = new THREE.LineSegments(geometry, surroundLineMaterial); line.name = 'surroundLine'; line.applyMatrix4(cityBuildings.matrix.clone()) cityBuildings.parent.add(line) }
updateData = () => { if (!this.isStart) return false; const dt = this.clock.getDelta(); this.time.value += dt; this.startTime.value += dt; if (this.startTime.value >= this.startLength.value) { this.startTime.value = this.startLength.value; } } }
const box = document.getElementById('box')
const scene = new THREE.Scene()
const camera = new THREE.PerspectiveCamera(75, box.clientWidth / box.clientHeight, 0.1, 1000000) camera.position.set(600, 750, -1221)
const renderer = new THREE.WebGLRenderer({ antialias: true, alpha: true }) renderer.setSize(box.clientWidth, box.clientHeight) renderer.setPixelRatio(Math.min(window.devicePixelRatio, 2)); renderer.setClearColor(new THREE.Color('#32373E'), 1);
const controls = new OrbitControls(camera, renderer.domElement) controls.enableDamping = true
window.onresize = () => { renderer.setSize(box.clientWidth, box.clientHeight) camera.aspect = box.clientWidth / box.clientHeight camera.updateProjectionMatrix() }
box.appendChild(renderer.domElement)
// 坐标轴 scene.add(new THREE.AxesHelper(100000)) const light = new THREE.AmbientLight(0xadadad, 3); // 环境光，soft white light const directionalLight = new THREE.DirectionalLight(0xffffff, 1.5); // 方向光 directionalLight.position.set(100, 100, 0); scene.add(light); scene.add(directionalLight);
// 实例化 const city = new City({}); scene.add(city.group);// 渲染 animate() function animate() { city.updateData(); controls.update() renderer.render(scene, camera) requestAnimationFrame(animate) }