今天我们来用ThreeJS的库实现一个波纹粒子效果，我们用到的ThreeJS的库有CanvasRenderer.js，OrbitControls.js，Projector.js，stats.min.js和three.js。这些库都是不可或缺的，我们先来看看实现的效果，如下图所示。
我们再来看看项目结构是怎么样的，项目结构如下图所示。
我们的效果全部写在了index.html里，现在我们直接贴出index.html的代码，同学们可以直接拿来运行，代码如下。
<!DOCTYPE html><html lang="en"><head> ???<meta charset="UTF-8"> ???<title>演示页面</title> ???<script src="three.js"></script> ???<script src="Projector.js"></script> ???<script src="CanvasRenderer.js"></script> ???<script src="stats.min.js"></script> ???<script src="OrbitControls.js"></script></head><body></body><script> ???var SEPARATION = 200, ???????AMOUNTX = 60, ???????AMOUNTY = 60; ???var container, stats; ???var camera, scene, renderer, controls; ???var particles, particle, count = 0; ???var windowHalfX = window.innerWidth / 2; ???var windowHalfY = window.innerHeight / 2; ???var raycaster = new THREE.Raycaster(); ???var mouse = new THREE.Vector2(); ???function init() { ???????container = document.createElement(‘div‘); ???????document.body.appendChild(container); ???????camera = new THREE.PerspectiveCamera(75, window.innerWidth / window.innerHeight, 1, 10000); ???????scene = new THREE.Scene(); ???????/** ????????* 设置光源 ????????* */ ???????//点光源 ???????var point = new THREE.PointLight(0xffffff);//白光 ???????point.position.set(1200, 1200, 1200);//点光源位置 ???????scene.add(point);//点光源添加进场景 ???????//环境光 ???????var ambient = new THREE.AmbientLight(0x999999);//白光 ???????scene.add(ambient);//环境光添加进场景 ???????//模型 ???????var cubeGeometry = new THREE.CubeGeometry(1000, 1000, 1000); ???????var cubeMaterial = new THREE.MeshLambertMaterial({ ???????????color:0xffff00 ???????????//side:THREE.DoubleSide ???????});//材质对象 ???????var cubeMesh = new THREE.Mesh(cubeGeometry, cubeMaterial);//网格模型对象 ???????cubeMesh.translateY(500); ???????scene.add(cubeMesh);//正方体网格模型添加到场景中 ???????//粒子 ???????particles = new Array(); ???????var PI2 = Math.PI * 2; ???????var material = new THREE.SpriteCanvasMaterial({ ???????????color: 0xffffff, ???????????program: function(context) { ???????????????context.beginPath(); ???????????????context.arc(0, 0, 0.5, 0, PI2, true); ???????????????context.fill(); ???????????} ???????}); ???????var i = 0; ???????for (var ix = 0; ix < AMOUNTX; ix++) { ???????????for (var iy = 0; iy < AMOUNTY; iy++) { ???????????????particle = particles[i++] = new THREE.Sprite(material); ???????????????particle.position.x = ix * SEPARATION - ((AMOUNTX * SEPARATION) / 2); ???????????????particle.position.z = iy * SEPARATION - ((AMOUNTY * SEPARATION) / 2); ???????????????scene.add(particle); ???????????} ???????} ???????/** ????????* 创建渲染器对象 ????????* */ ???????renderer = new THREE.CanvasRenderer(); ???????renderer.setPixelRatio(window.devicePixelRatio); ???????renderer.setSize(window.innerWidth, window.innerHeight); ???????container.appendChild(renderer.domElement); ???????window.addEventListener(‘resize‘, onWindowResize, false); ???????//交互控制器 ???????/** ????????* 鼠标键盘事件监听器 ????????* */ ???????controls = new THREE.OrbitControls(camera, renderer.domElement); ???????controls.enableDamping = true; ???????controls.dampingFactor = 0.1; ???????controls.screenSpacePanning = true; ???????controls.minDistance = 0; ???????controls.maxDistance = 5000; ???????controls.maxPolarAngle = 2*Math.PI; ???????/** ????????* 模型拾取 ????????* */ ???????mouse.x = -10000; ???????mouse.y = -10000; ???????function onMouseMove( event ) { ???????????// calculate mouse position in normalized device coordinates ???????????// (-1 to +1) for both components ???????????mouse.x = ( event.clientX / window.innerWidth ) * 2 - 1; ???????????mouse.y = - ( event.clientY / window.innerHeight ) * 2 + 1; ???????} ???????window.addEventListener( ‘mousemove‘, onMouseMove, false ); ???} ???function pickUp() { ???????// update the picking ray with the camera and mouse position ???????raycaster.setFromCamera( mouse, camera ); ???????// calculate objects intersecting the picking ray ???????var intersects = raycaster.intersectObjects( scene.children ); ???????for ( var i = 0; i < intersects.length; i++ ) { ???????????intersects[ i ].object.material.color.set( 0xff00ff ); ???????} ???????if(intersects.length === 0){ ???????????scene.children[2].material.color.set( 0xffff00 ); ???????????for(var i=3; i<scene.children.length; i++){ ???????????????scene.children[i].material.color.set( 0xffffff ); ???????????} ???????} ???????renderer.render( scene, camera ); ???} ???function onWindowResize() { ???????windowHalfX = window.innerWidth / 2; ???????windowHalfY = window.innerHeight / 2; ???????camera.aspect = window.innerWidth / window.innerHeight; ???????camera.updateProjectionMatrix(); ???????renderer.setSize(window.innerWidth, window.innerHeight); ???} ???var rad = 0; ???function render() { ???????camera.position.set(2600, 500, 2600); ???????camera.up = new THREE.Vector3(0, 1, 0); ???????camera.lookAt(new THREE.Vector3(0, 500, 0)); ???????var i = 0; ???????for (var ix = 0; ix < AMOUNTX; ix++) { ???????????for (var iy = 0; iy < AMOUNTY; iy++) { ???????????????particle = particles[i++]; ???????????????particle.position.y = (Math.sin((ix + count) * 0.2) * 500) + ???????????????????(Math.sin((iy + count) * 0.2) * 500); ???????????????particle.scale.y = (Math.sin((ix + count) * 0.3) + 1) * 3 + ???????????????????(Math.sin((iy + count) * 0.3) + 1) * 3; ???????????????particle.scale.x = (Math.sin((ix + count) * 0.3) + 1) * 3 + ???????????????????(Math.sin((iy + count) * 0.3) + 1) * 3; ???????????} ???????????scene.children[2].translateY(Math.cos(ix + count/2)*5); ???????} ???????//模型旋转 ???????scene.children[2].rotateY(Math.PI/180); ???????camera.position.x = 2600*Math.cos(Math.PI/180*rad); ???????camera.position.z = -2600*Math.sin(Math.PI/180*rad); ???????//点光源位置 ???????scene.children[0].position.x = 1200*Math.cos(Math.PI/180*rad+Math.PI*0.1); ???????scene.children[0].position.z = -1200*Math.sin(Math.PI/180*rad+Math.PI*0.1); ???????????????controls.update(); ???????renderer.render(scene, camera); ???????count += 0.1; ???????rad += 0.2; ???} ???function animate() { ???????requestAnimationFrame(animate); ???????render(); ???????pickUp(); ???} ???init(); ???animate();</script></html> 我们分析一下段代码，首先我们看到requestAnimationFrame，这是主循环，我们在init()初始化函数中往scene场景中添加了particle粒子，这些粒子是在XoZ平面上均匀网格散布的。然后我们主循环每次render()都改变粒子的Y坐标，修改的规则是通过sin函数进行Y轴向扰动。每次重绘我们都修改Y坐标，就实现了粒子的波动特效。
代码很简单，希望能帮助大家做出一套粒子波动的背景特效。鲫鱼非常愿意和大家讨论学习WebGL和ThreeJS的技术，欢迎大家留言，谢谢。本文系原创，如需引用请注明出处：https://www.cnblogs.com/ccentry/p/10125686.html
ThreeJS实现波纹粒子效果
原文地址：https://www.cnblogs.com/ccentry/p/10125686.html