Three.js 快速入门：核心五步构建3D场景

var renderer;
function initThree(){
 width = document.getElementById("box").clientWidth;
 height = document.getElementById("box").clientHeight;
 /**
 //声明渲染器对象：WebGLRenderer 
 renderer=new THREE.WebGLRenderer({ 
  antialias:true, //是否开启反锯齿 
  precision:"highp", //着色精度选择 
  alpha:true,  //是否可以设置背景色透明 
  premultipliedAlpha:false, 
  stencil:false, 
  preserveDrawingBuffer:true, //是否保存绘图缓冲 
  maxLights:1  //maxLights:最大灯光数 
 }); 
 */
 renderer = new THREE.WebGLRenderer({
 antialias:true
 });/*生成渲染器对象（属性：抗锯齿效果为设置有效）*/
 renderer.setSize(width,height);
 document.getElementById("box").appendChild(renderer.domElement);
 /*设置canvas背景色(clearColor)和背景色透明度（clearAlpha） */
 renderer.setClearColor(0xFFFFFF,1.0);
}

var camera;
function initCamera(){
 /*PerspectiveCamera的四个参数
 参数1：为视野角 ,
 参数2：纵横比。这参数几乎总是使用的元素的宽度除以高度，否则你会看到像老电影中的那样,图像被压扁了.
 参数3：相机允许离物体的最近距离.
 参数4；相机允许离物体的最远距离.默认情况之下,相机的上方向为Y轴,右方向为X轴,向里为Z轴.*/
 camera = new THREE.PerspectiveCamera(45,width/height,1,10000);
 camera.position.x = 0;
 camera.position.y = 1000;
 camera.position.z = 0;
 camera.up.x = 0;
 camera.up.y = 0;
 camera.up.z = 1;
 camera.lookAt({x:0,y:0,z:0}); //设置视野的中心坐标 
}

var scene;
function initScene(){
 scene = new THREE.Scene();
}

var light;
function initLight(){
 light = new THREE.DirectionalLight(0xFF0000, 1.0, 0); //平行光
 light.position.set(100, 100, 200); //设置光源位置
 scene.add(light); //将官员添加到场景
}

var sphere;
function initObject(){
 sphere = new THREE.Mesh(new THREE.SphereGeometry(200,200)/*设置球体的大小*/,new THREE.MeshLambertMaterial({color:0xff0000})/*设置球体的材质*/); //材质设定 
 scene.add(sphere); 
 sphere.position.set(0,0,0); /*设置物体位置*/
} 

function threeExcute(){ 
 initThree(); 
 initCamera(); 
 initScene(); 
 initLight(); 
 initObject(); 
 renderer.clear(); 
 renderer.render(scene,camera); 
}

<!DOCTYPE html>
<html lang="en">
<head>
 <meta charset="UTF-8">
 <title>Document</title>
 <script src="http://cdn.bootcss.com/three.js/r83/three.min.js"></script>
</head>
 <!-- Three.js的核心五步就是：
 1.设置three.js渲染器
 2.设置摄像机camera
 3.设置场景scene
 4.设置光源light
 5.设置物体object 
 -->
 <script>
 // 1.设置three.js渲染器
 var renderer;
 function initThree(){
 width = document.getElementById("box").clientWidth;
 height = document.getElementById("box").clientHeight;
 renderer = new THREE.WebGLRenderer({
 antialias:true
 });/*生成渲染器对象（属性：抗锯齿效果为设置有效）*/
 renderer.setSize(width,height);
 document.getElementById("box").appendChild(renderer.domElement);
 /*设置canvas背景色(clearColor)和背景色透明度（clearAlpha） */
 renderer.setClearColor(0xFFFFFF,1.0);
 }
 // 2.设置摄像机camera
 var camera;
 function initCamera(){
 camera = new THREE.PerspectiveCamera(45,width/height,1,10000);
 camera.position.x = 0;
 camera.position.y = 1000;
 camera.position.z = 0;
 camera.up.x = 0;
 camera.up.y = 0;
 camera.up.z = 1;
 camera.lookAt({x:0,y:0,z:0}); //设置视野的中心坐标 
 }
 // 3.设置场景
 var scene;
 function initScene(){
 scene = new THREE.Scene();
 }
 // 4.设置光源light
 var light;
 function initLight(){
 light = new THREE.DirectionalLight(0xFF0000, 1.0, 0); //平行光
 light.position.set(100, 100, 200); //设置光源位置
 scene.add(light); //将官员添加到场景
 }
 //5.设置物体 
 var sphere;
 function initObject(){
 sphere = new THREE.Mesh(new THREE.SphereGeometry(200,200)/*设置球体的大小*/,new THREE.MeshLambertMaterial({color:0xff0000})/*设置球体的材质*/); //材质设定 
  scene.add(sphere); 
  sphere.position.set(0,0,0); /*设置物体位置*/
 } 
 //6.执行 
 function threeExcute(){ 
  initThree(); 
  initCamera(); 
  initScene(); 
  initLight(); 
  initObject(); 
  renderer.clear(); 
  renderer.render(scene,camera); 
 } 
 </script>
 <style type="text/css">
 div#box{
  border: none;
  cursor: move;
  width: 1400px;
  height: 600px;
  background-color: #EEEEEE;
  }
 </style>
 <body onload="threeExcute();">
 <div id="box"></div>
 </body>
</html>