Three.js是一个跨浏览器的脚本，使用JavaScript函数库或API来在网页浏览器中创建和展示动画的三维计算机图形。Three.js使用WebGL。源代码托管在GitHub。

国庆期间整理电脑数据，发现一段用three.js写的光射线效果代码，好像是从阿里云推广的专题页面扒下来的。效果酷炫，适用于banner的动态背景，给人一种高大上的感觉。

如图，点击查看实例。

代码：

(function () {
function init() {
//自适应屏幕
window.addEventListener('resize', onWindowResize, false);
function onWindowResize() {
var height = document.body.clientHeight;
var width = document.body.clientWidth;
camera.aspect = width / height;
camera.updateProjectionMatrix();
renderer.setSize(width, height);
}

var group = new THREE.Group();
var group2 = new THREE.Group();
var group3 = new THREE.Group();
var groupD = new THREE.Group();
var groupDD = new THREE.Group();
groupD.add(group2);
group.add(groupD);
groupDD.add(group3);
group.add(groupDD);

//自适应屏幕
// window.addEventListener( 'resize', onWindowResize, false );
// function onWindowResize() {
// camera.aspect = window.innerWidth / window.innerHeight;
// camera.updateProjectionMatrix();
// renderer.setSize( window.innerWidth, window.innerHeight );
// }

var scene = new THREE.Scene();
//scene.fog = new THREE.Fog(0xffffff,68,700);//雾化的颜色，近，远
scene.fog = new THREE.FogExp2(0x000000, 0.0052);//雾化的颜色，浓度

var camera = new THREE.PerspectiveCamera(90, window.innerWidth / window.innerHeight, 1, 1000);
// antialias 抗锯齿
var renderer = new THREE.WebGLRenderer({ alpha: false, antialias: false });
renderer.setClearColor(0x000000, 0);
renderer.setSize(window.innerWidth, window.innerHeight);
renderer.shadowMapEnabled = true;//渲染器支持阴影

function pm() {
for (var jiaodu = 0; jiaodu <= 360; jiaodu++) {
dx = Math.cos(jiaodu) * 10 * 2.5;
dy = -0.5 * jiaodu * Math.PI;//互相垂直
//dy = -0.5*Math.PI; //互相平行
dz = Math.sin(jiaodu) * 25;
var planeGeometryX = new THREE.PlaneGeometry(0.6, 10, 0);
planeMaterialX = new THREE.MeshPhongMaterial();
planeMaterialX.opacity = 1;
planeMaterialX.side = THREE.DoubleSide;
//planeMaterialX.wireframe =true;
planeMaterialX.transparent = true;
planeMaterialX.color = new THREE.Color(0xffffff);
var dd1 = new THREE.Mesh(planeGeometryX, planeMaterialX);
dd1.position.x = dx;
dd1.rotation.y = dy;
dd1.position.z = dz;
dd1.position.y = -Math.random() * 220;
dd1.scale.y = Math.random() * 1;
dd1.scale.x = Math.random() * 1;
dd1.scale.z = Math.random() * 1;
group2.add(dd1);
group2.position.set(0, 0, 0);
}

for (var jiaodu = 0; jiaodu <= 360; jiaodu++) {
dx = Math.cos(jiaodu) * 10 * 2.5;
dy = -0.5 * jiaodu * Math.PI;//互相垂直
//dy = 0.5*Math.PI; //互相平行
dz = Math.sin(jiaodu) * 25;
var planeGeometryX = new THREE.PlaneGeometry(0.5, 10, 0);
planeMaterialX = new THREE.MeshPhongMaterial();
planeMaterialX.opacity = 0.7;
planeMaterialX.side = THREE.DoubleSide;
//planeMaterialX.wireframe =true;
planeMaterialX.transparent = true;
planeMaterialX.color = new THREE.Color(0xffffff);
var dd1 = new THREE.Mesh(planeGeometryX, planeMaterialX);
dd1.position.x = dx;
dd1.rotation.y = dy;
dd1.position.z = dz;
dd1.position.y = -Math.random() * 220;
dd1.scale.y = Math.random() * 4;
dd1.scale.x = Math.random() * 2;
dd1.scale.z = Math.random() * 1;
group3.add(dd1);
group3.position.set(0, 0, 0);
}

for (var jiaodu2 = 0; jiaodu2 <= 60; jiaodu2++) {
dx2 = Math.cos(jiaodu2) * 10;
dz2 = Math.sin(jiaodu2) * 10;
dy2 = Math.cos(Math.random() * jiaodu2) * 0.5;
var planeGeometryX2 = new THREE.SphereGeometry(Math.cos(jiaodu2) * 2, Math.sin(jiaodu2), 0);
planeMaterialX2 = new THREE.MeshLambertMaterial();
planeMaterialX2.side = THREE.DoubleSide;
//planeMaterialX2.wireframe =true;
planeMaterialX2.transparent = true;
planeMaterialX2.opacity = 0.5;
planeMaterialX2.color = new THREE.Color(0xffffff);
var dd2 = new THREE.Mesh(planeGeometryX2, planeMaterialX2);
dd2.position.x = dx2 * 2.5;
dd2.position.z = dz2 * 2.5;

dd2.rotation.y = 0.5 * jiaodu2 * Math.PI;
dd2.position.y = -Math.random() * 240;

group2.add(dd2);
group2.position.set(0, 0, 0);

}

for (var jiaodu2 = 0; jiaodu2 <= 60; jiaodu2++) {
dx2 = Math.cos(jiaodu2) * 10;
dz2 = Math.sin(jiaodu2) * 10;
dy2 = Math.cos(Math.random() * jiaodu2) * 0.5;
var planeGeometryX2 = new THREE.SphereGeometry(Math.cos(jiaodu2) * 2, Math.sin(jiaodu2), 0);
planeMaterialX2 = new THREE.MeshLambertMaterial();
planeMaterialX2.side = THREE.DoubleSide;
//planeMaterialX2.wireframe =true;
planeMaterialX2.transparent = true;
planeMaterialX2.opacity = 0.5;
planeMaterialX2.color = new THREE.Color(0xffffff);
var dd2 = new THREE.Mesh(planeGeometryX2, planeMaterialX2);
dd2.position.x = dx2 * 2.5;
dd2.position.z = dz2 * 2.5;

dd2.rotation.y = 0.5 * jiaodu2 * Math.PI;
dd2.position.y = -Math.random() * 240;

group3.add(dd2);
group3.position.set(0, 0, 0);

}
}
pm();

// 设置摄像机
camera.position.set(-30, 30, 30);
camera.lookAt(scene.position);// 摄像机指向场景中心

//设置光源
var spotLight = new THREE.SpotLight();
spotLight.position.set(0, 10, 50);
//spotLight.castShadow = true;
spotLight.intensity = 10;
scene.add(spotLight);

var spotLight2 = new THREE.SpotLight(0x00C1DE);
spotLight2.position.set(0, 50, 0);
spotLight2.intensity = 4;
scene.add(spotLight2);

var spotLight3 = new THREE.SpotLight();
spotLight3.position.set(50, 10, -50);
spotLight3.intensity = 5;
scene.add(spotLight3);

//设置环境光
var ambientLight = new THREE.AmbientLight(0x222222);
scene.add(ambientLight);

// 将渲染输出到叫"WebGL-output"的div中
document.getElementById("WebGL-output").appendChild(renderer.domElement);
//renderer.render(scene, camera);

var step = 0;
renderScene();
scene.add(group);

group3.position.y = -240;
function renderScene() {
step += 0.005;
r = 0.2 * Math.abs(Math.cos(step));
g = 0.1 * Math.abs(Math.sin(step));
b = 0.4 * Math.abs(Math.cos(step));
spotLight.color = new THREE.Color(r, g, b * 2);

spotLight3.color = new THREE.Color(b, r * 2, g);
groupD.rotation.x = 0.5 * Math.PI;
groupD.rotation.z = 0.25 * Math.PI;
groupD.rotation.y = -0.25 * Math.PI;
groupDD.rotation.x = .5 * Math.PI;
groupDD.rotation.z = 0.25 * Math.PI;
groupDD.rotation.y = -0.25 * Math.PI;
// group2.rotation.y = -0.57*Math.PI;
// group3.rotation.y = -0.57*Math.PI;
group2.rotation.y -= 0.0025;
group3.rotation.y -= 0.0025;
if (group2.position.y < 270) {
group2.position.y += 0.5;
} else {
group2.position.y = -200;
}
if (group3.position.y < 290) {
group3.position.y += 0.5;
} else {
//scene.remove(group);
group3.position.y = -210;
}
//spotLight.position.x =20*Math.abs(Math.cos(step));
requestAnimationFrame(renderScene);//循环执行某动作
renderer.render(scene, camera);// 渲染这个场景
}
//end

onWindowResize();
}
init();
})();