<script src="/lib/three.js"></script>
<script src="/lib/js/controls/OrbitControls.js"></script>
<script src="/lib/js/libs/stats.min.js"></script>
<script src="/lib/js/libs/dat.gui.min.js"></script>
<script>
    var renderer;
    function initRender() {
        renderer = new THREE.WebGLRenderer({antialias: true});
        renderer.setSize(window.innerWidth, window.innerHeight);
        //告诉渲染器需要阴影效果
        renderer.shadowMap.enabled = true;
        renderer.shadowMap.type = THREE.PCFSoftShadowMap; // 默认的是,没有设置的这个清晰 THREE.PCFShadowMap
        document.body.appendChild(renderer.domElement);
    }

    var camera;
    function initCamera() {
        camera = new THREE.PerspectiveCamera(45, window.innerWidth / window.innerHeight, 0.1, 1000);
        camera.position.set(0, 40, 100);
        camera.lookAt(new THREE.Vector3(0, 0, 0));
    }

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

    //初始化dat.GUI简化试验流程
    var gui;
    function initGui() {
        //声明一个保存需求修改的相关数据的对象
        gui = {
        };
        var datGui = new dat.GUI();
        //将设置属性添加到gui当中,gui.add(对象,属性,最小值,最大值)
    }

    var ambientLight,directionalLight;
    function initLight() {
        ambientLight = new THREE.AmbientLight("#111111");
        scene.add(ambientLight);

        spotLight = new THREE.PointLight("#ffffff");
        spotLight.position.set(15, 30, 10);

        //告诉平行光需要开启阴影投射
        spotLight.castShadow = true;

        scene.add(spotLight);
    }

    var cube,plane;
    function initModel() {

        //辅助工具
        var helper = new THREE.AxisHelper(10);
        scene.add(helper);

        //球体
        var sphereGeometry = new THREE.SphereGeometry(10,30,30);
        var sphereMaterial = new THREE.MeshPhongMaterial({color:0xeeeeee});
        var sphere = new THREE.Mesh(sphereGeometry,sphereMaterial);
        sphere.position.set(-20,20,0);

        sphere.castShadow = true;

        scene.add(sphere);

        //立方体
        var cubeGeometry = new THREE.CubeGeometry(10,10,10);

        var cubeMaterial = new THREE.MeshPhongMaterial({color: 0x00ffff});

        cube = new THREE.Mesh(cubeGeometry, cubeMaterial);
        cube.position.x = 30;
        cube.position.y = 5;
        cube.position.z = -5;

        //告诉立方体需要投射阴影
        cube.castShadow = true;

        scene.add(cube);

        //底部平面
        var planeGeometry = new THREE.PlaneGeometry(5000, 5000, 20, 20);
        var planeMaterial = new THREE.MeshPhongMaterial({color: 0xaaaaaa});

        plane = new THREE.Mesh(planeGeometry, planeMaterial);
        plane.rotation.x = -0.5 * Math.PI;
        plane.position.y = -0;

        //告诉底部平面需要接收阴影
        plane.receiveShadow = true;

        scene.add(plane);

    }

    //初始化性能插件
    var stats;
    function initStats() {
        stats = new Stats();
        document.body.appendChild(stats.dom);
    }

    //用户交互插件 鼠标左键按住旋转,右键按住平移,滚轮缩放
    var controls;
    function initControls() {

        controls = new THREE.OrbitControls(camera, renderer.domElement);

        // 如果使用animate方法时,将此函数删除
        //controls.addEventListener( 'change', render );
        // 使动画循环使用时阻尼或自转 意思是否有惯性
        controls.enableDamping = true;
        //动态阻尼系数 就是鼠标拖拽旋转灵敏度
        //controls.dampingFactor = 0.25;
        //是否可以缩放
        controls.enableZoom = true;
        //是否自动旋转
        controls.autoRotate = false;
        //设置相机距离原点的最远距离
        controls.minDistance = 50;
        //设置相机距离原点的最远距离
        controls.maxDistance = 200;
        //是否开启右键拖拽
        controls.enablePan = true;
    }

    function render() {
        renderer.render(scene, camera);
    }

    //窗口变动触发的函数
    function onWindowResize() {

        camera.aspect = window.innerWidth / window.innerHeight;
        camera.updateProjectionMatrix();
        render();
        renderer.setSize(window.innerWidth, window.innerHeight);

    }

    function animate() {
        //更新控制器
        render();

        //更新性能插件
        stats.update();

        controls.update();

        requestAnimationFrame(animate);
    }

    function draw() {
        initGui();
        initRender();
        initScene();
        initCamera();
        initLight();
        initModel();
        initControls();
        initStats();

        animate();
        window.onresize = onWindowResize;
    }
</script>