example/lights/Shandow.html

<!DOCTYPE html>
<html lang="en">

<head>
    <meta charset="UTF-8">
    <title>平行光 - 投影</title>
    <style>
        body {
            margin: 0;
            overflow: hidden;
            /* 隐藏body窗口区域滚动条 */
        }
    </style>
    <!--引入three.js三维引擎-->
    <script src="../js/threejs/three.js"></script>
    <!-- 引入threejs扩展控件OrbitControls.js -->
    <script src="../js/controls/OrbitControls.js"></script>
</head>

<body>
    <script>
        /**
         * 创建场景对象Scene
         */
        var scene = new THREE.Scene();
        /**
         * 创建网格模型
         */
        var geometry = new THREE.BoxGeometry(40, 100, 40); //创建一个立方体几何对象Geometry
        var material = new THREE.MeshLambertMaterial({
            color: 0x0000ff,
            side: THREE.DoubleSide, //两面可见
        }); //材质对象Material
        var mesh = new THREE.Mesh(geometry, material); //网格模型对象Mesh
        scene.add(mesh); //网格模型添加到场景中
        // 设置产生投影的网格模型
        mesh.castShadow = true;
        mesh.position.set(0,0,0)

        //创建一个平面几何体作为投影面
        var planeGeometry = new THREE.PlaneGeometry(300, 200);
        var planeMaterial = new THREE.MeshLambertMaterial({
            color: 0x999999,
            side: THREE.DoubleSide, //两面可见
        }); //材质对象Material

        // 平面网格模型作为投影面
        var planeMesh = new THREE.Mesh(planeGeometry, planeMaterial); //网格模型对象Mesh
        scene.add(planeMesh); //网格模型添加到场景中
        planeMesh.rotateX(-Math.PI / 2); //旋转网格模型
        planeMesh.position.y = -50; //设置网格模型y坐标
        // 设置接收阴影的投影面
        planeMesh.receiveShadow = true;
        /**
         * 光源设置
         */
        //环境光   环境光颜色RGB成分分别和物体材质颜色RGB成分分别相乘
        var ambient = new THREE.AmbientLight(0x444444);
        scene.add(ambient); //环境光对象添加到scene场景中

        // 方向光
        var directionalLight = new THREE.DirectionalLight(0xffffff, 1);
        // 设置光源位置
        directionalLight.position.set(60, 100, 40);
        scene.add(directionalLight);
        // 设置用于计算阴影的光源对象
        directionalLight.castShadow = true;
        // 设置计算阴影的区域，最好刚好紧密包围在对象周围
        // 计算阴影的区域过大：模糊  过小：看不到或显示不完整
        directionalLight.shadow.camera.near = 0.5;
        directionalLight.shadow.camera.far = 300;
        directionalLight.shadow.camera.left = -50;
        directionalLight.shadow.camera.right = 50;
        directionalLight.shadow.camera.top = 200;
        directionalLight.shadow.camera.bottom = -100;
        // 设置mapSize属性可以使阴影更清晰，不那么模糊
        directionalLight.shadow.mapSize.set(1024,1024)
        console.log(directionalLight.shadow.camera);
        /**
         * 相机设置
         */
        var width = window.innerWidth; //窗口宽度
        var height = window.innerHeight; //窗口高度
        var k = width / height; //窗口宽高比
        var s = 150; //三维场景显示范围控制系数，系数越大，显示的范围越大
        //创建相机对象
        var camera = new THREE.OrthographicCamera(-s * k, s * k, s, -s, 1, 1000);
        camera.position.set(200, 300, 200); //设置相机位置
        camera.lookAt(scene.position); //设置相机方向(指向的场景对象)
        /**
         * 创建渲染器对象
         */
        var renderer = new THREE.WebGLRenderer();
        renderer.setSize(width, height); //设置渲染区域尺寸
        renderer.setClearColor(0xb9d3ff, 1); //设置背景颜色
        document.body.appendChild(renderer.domElement); //body元素中插入canvas对象
        // 设置渲染器，允许场景中使用阴影贴图
        renderer.shadowMap.enabled = true;
        // 渲染函数
        function render() {
            renderer.render(scene, camera); //执行渲染操作
        }
        render();
        //创建控件对象  相机对象camera作为参数   控件可以监听鼠标的变化，改变相机对象的属性
        var controls = new THREE.OrbitControls(camera);
        //监听鼠标事件，触发渲染函数，更新canvas画布渲染效果
        controls.addEventListener('change', render);
    </script>
</body>

</html>