Three.js 发散飞线教程
发散飞线 ·Diffuse 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
- THREE.Points 粒子点渲染
- QuadraticBezierCurve3 二次贝塞尔曲线路径
- Raycaster 鼠标拾取与交互
- BufferGeometry 自定义顶点/索引数据
requestAnimationFrame渲染循环与resize自适应
效果说明
本案例演示发散飞线效果：从中心或锚点定时生成随机曲线，沿路径播放粒子流光，支持鼠标拾取、绘制或拖拽交互；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。 - 曲线类
getPoints(n)将贝塞尔/样条离散为路径点，再写入 BufferGeometry 驱动飞线或路径动画。
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
- 用曲线离散点构建 BufferGeometry，写入自定义 attribute 驱动动画
- 创建 OrbitControls（及 Raycaster 等交互控件，若源码包含）
- 在定时器或 GSAP 时间轴中更新 uniform / 变换，驱动特效播放
- 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 Stats from 'three/examples/jsm/libs/stats.module.js';
class InitFly { constructor({ texture } = opt) { this.flyId = 0; //id this.flyArr = []; //存储所有飞线 this.baicSpeed = 1; //基础速度 this.texture = 0.0; if (texture && !texture.isTexture) { this.texture = new THREE.TextureLoader().load(texture) } else { this.texture = texture; } this.flyShader = { vertexshader:
uniform float size; uniform float time; uniform float u_len; attribute float u_index; varying float u_opacitys; void main() { if( u_index < time + u_len && u_index > time){ float u_scale = 1.0 - (time + u_len - u_index) /u_len; u_opacitys = u_scale; vec4 mvPosition = modelViewMatrix * vec4(position, 1.0); gl_Position = projectionMatrix * mvPosition; gl_PointSize = sizeu_scale300.0 / (-mvPosition.z); } }, fragmentshader:uniform sampler2D u_map; uniform float u_opacity; uniform vec3 color; uniform float isTexture; varying float u_opacitys; void main() { vec4 u_color = vec4(color,u_opacity * u_opacitys); if( isTexture != 0.0 ){ gl_FragColor = u_color * texture2D(u_map, vec2(gl_PointCoord.x, 1.0 - gl_PointCoord.y)); }else{ gl_FragColor = u_color; } }} } /**- [addFly description]
- * @param {String} opt.color [颜色_透明度]
- @param {Array} opt.curve [线的节点]
- @param {Number} opt.width [宽度]
- @param {Number} opt.length [长度]
- @param {Number} opt.speed [速度]
- @param {Number} opt.repeat [重复次数]
- @return {Mesh} [return 图层]
- 根据线条组生成路径
- [remove 删除]
- @param {Object} mesh [当前飞线]
- [animation 动画]
- @param {Number} delta [执行动画间隔时间]
function pad2(c) { return c.length == 1 ? '0' + c : '' + c; } return _arr; } }
function Initialize(opt) { var camera, controls, scene, renderer; var clock = new THREE.Clock(); var thm = this; var df_Mouse, df_Raycaster; var df_Width, df_Height; //当前盒子的高宽 var df_canvas;
var stats
function init() { camera = new THREE.PerspectiveCamera(60, window.innerWidth / window.innerHeight, 1, 10000); camera.position.set(0, 400, 400); camera.lookAt(new THREE.Vector3(0, 0, 0)) scene = new THREE.Scene()
renderer = new THREE.WebGLRenderer({ antialias: true }); renderer.setPixelRatio(window.devicePixelRatio * 1.3); renderer.setSize(window.innerWidth, window.innerHeight);
document.querySelector(opt.id).appendChild(renderer.domElement); df_canvas = renderer.domElement controls = new OrbitControls(camera, renderer.domElement); window.addEventListener('resize', onWindowResize, false); renderer.domElement.addEventListener('mouseup', onDocumentMouseUp, false); df_Width = window.innerWidth; df_Height = window.innerHeight; df_Mouse = new THREE.Vector2(); df_Raycaster = new THREE.Raycaster(); // onload if (opt.load) { opt.load({ camera, controls, scene, renderer }) } if (Stats) { stats = new Stats(); document.querySelector(opt.id).appendChild(stats.dom); } }
function onDocumentMouse(event) { event.preventDefault(); df_Mouse.x = ((event.clientX - df_canvas.getBoundingClientRect().left) / df_canvas.offsetWidth) * 2 - 1; df_Mouse.y = -((event.clientY - df_canvas.getBoundingClientRect().top) / df_canvas.offsetHeight) * 2 + 1; df_Raycaster.setFromCamera(df_Mouse, camera); return { mouse: df_Mouse, event: event, raycaster: df_Raycaster } } function onWindowResize() { camera.aspect = window.innerWidth / window.innerHeight; camera.updateProjectionMatrix(); renderer.setSize(window.innerWidth, window.innerHeight); } function onDocumentMouseUp(event) { if (typeof opt.mouseUp === 'function') { opt.mouseUp(onDocumentMouse(event)) } } function animate() { requestAnimationFrame(animate); var delta = clock.getDelta(); renderer.render(scene, camera); if (opt.animation) opt.animation(delta); if (stats) stats.update(); } init(); animate(); }
var _Fly; var GL = new Initialize({ id: "#box", animation: function (dalte) { if (_Fly) { // 更新线 必须 _Fly.animation(dalte); } }, load({ scene, camera }) { _Fly = new InitFly({ texture: FILE_HOST + "threeExamples/application/flyLine/point.png" }); let index = 0; var time = setInterval(() => { if (index >= 4000) { clearInterval(time) } var x = 0; var z = 0; var x1 = THREE.MathUtils.randFloat(-200, 200); var z1 = THREE.MathUtils.randFloat(-200, 200); var curve = new THREE.QuadraticBezierCurve3( new THREE.Vector3(x, 0, z), new THREE.Vector3((x + x1) / 2, THREE.MathUtils.randInt(200, 420), (z1 + z) / 2), new THREE.Vector3(x1, 0, z1) ); var points = curve.getPoints(500); var flyMesh = _Fly.addFly({ color:rgba(${THREE.MathUtils.randInt(0, 255)},${THREE.MathUtils.randInt(0, 255)},${THREE.MathUtils.randInt(0, 255)},1), curve: points, width: 9, length: 150, speed: 1, repeat: Infinity }) scene.add(flyMesh); index++; }) } })完整源码：GitHub
小结
- 本文提供发散飞线完整 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