function init(){

            var stats = initStats();

            //场景/相机/渲染器/坐标轴
            var scene = new THREE.Scene();

            var camera = new THREE.PerspectiveCamera(45,window.innerWidth/window.innerHeight,0.1,1000);
            camera.position.set(-30,40,30);
            camera.lookAt(scene.position);

            var renderer = new THREE.WebGLRenderer();
            renderer.setClearColor(new THREE.Color(0xEEEEEE));
            renderer.setSize(window.innerWidth,window.innerHeight);
            renderer.shadowMap.enabled = true;

            var axes = new THREE.AxesHelper(20);
            scene.add(axes);
            //底部
            var planeGeometry = new THREE.PlaneGeometry(60,20);
            var planeMeterial = new THREE.MeshLambertMaterial({color:0xffffff});
            var plane = new THREE.Mesh(planeGeometry,planeMeterial);
            plane.rotation.x = -0.5*Math.PI;
            plane.position.set(15,0,0);
            plane.receiveShadow = true;
            scene.add(plane);
            //方形
            var cubeGeometry = new THREE.BoxGeometry(4,4,4);
            var cubeMaterial = new THREE.MeshLambertMaterial({color:0xff0000});
            var cube = new THREE.Mesh(cubeGeometry,cubeMaterial);
            cube.position.set(-4,3,0);
            cube.castShadow = true;
            scene.add(cube);
            //圆形
            var sphereGeometry = new THREE.SphereGeometry(4,20,20);
            var sphereMaterial = new THREE.MeshLambertMaterial({color:0x7777ff});
            var sphere = new THREE.Mesh(sphereGeometry,sphereMaterial);
            sphere.position.set(20,4,2);
            sphere.castShadow = true;
            scene.add(sphere);
            //聚光灯
            var spotLight = new THREE.SpotLight(0xffffff);
            spotLight.position.set(-40,60,-10);
            spotLight.castShadow = true;
            scene.add(spotLight);
            //将渲染器放入dom
            document.getElementById("WebGL-output").appendChild(renderer.domElement);
            renderer.render(scene,camera);

            var step = 0;

            var controls = {
                rotationSpeed:0.02,
                bouncingSpeed:0.03
            };
            var gui = new dat.GUI();
            gui.add(controls,"rotationSpeed",0,0.5);
            gui.add(controls,"bouncingSpeed",0,0.5);

            renderScene();
            function renderScene(){
                stats.update();
                cube.rotation.x += controls.rotationSpeed;
                cube.rotation.y += controls.rotationSpeed;
                cube.rotation.z += controls.rotationSpeed;

                step += controls.bouncingSpeed;
                sphere.position.x = 20 + (10 * Math.cos(step));
                sphere.position.y = 2 + (10 * Math.abs( Math.sin(step) ));
                requestAnimationFrame(renderScene);
                renderer.render(scene,camera);
            }
            function initStats(){
                var stats = new Stats();
                stats.setMode(0);
                stats.domElement.style.position = "absolute";
                stats.domElement.style.left = "0";
                stats.domElement.style.top = "0";
                document.getElementById("Stats-output").appendChild(stats.domElement);
                return stats;
            }
            window.addEventListener("resize",function(){
                camera.aspect = window.innerWidth/window.innerHeight;
                camera.updateProjectionMatrix();
                renderer.setSize(window.innerWidth,window.innerHeight);
            })
        }
        window.onload = init;