<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.setClearColor(new THREE.Color(0xEEEEEE, 1.0)); //设置背景颜色
        renderer.setSize(window.innerWidth, window.innerHeight);
        document.body.appendChild(renderer.domElement);
    }

    var camera;

    function initCamera() {
        camera = new THREE.PerspectiveCamera(45, window.innerWidth / window.innerHeight, 1, 10000);
        camera.position.set(0, 0, 500);
    }

    var scene;

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

    var light;

    function initLight() {
        scene.add(new THREE.AmbientLight(0x404040));

        light = new THREE.DirectionalLight(0xffffff);
        light.position.set(1, 1, 1);
        scene.add(light);
    }

    function initModel() {

        //轴辅助 (每一个轴的长度)
        var object = new THREE.AxesHelper(500);
        scene.add(object);

        var material = new THREE.SpriteMaterial();

        for (var x = -5; x <= 5; x++) {
            for (var y = -5; y <= 5; y++) {
                var sprite = new THREE.Sprite(material);
                sprite.position.set(x * 10, y * 10, 0);
                scene.add(sprite);
            }
        }

    }

    //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 = 20;
        //设置相机距离原点的最远距离
        controls.maxDistance = 10000;
        //是否开启右键拖拽
        controls.enablePan = true;
    }

    //生成gui设置配置项
    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)
    }

    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
        controls.update();
        render();

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

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

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