Three.js - 使用 CubeCamera 创建反光效果

使用环境贴图可以创建虚假的反光效果,但是是静态的,并且不能实现镜面反射的效果,镜面所反射的物体是动态的,可以通过THREE.CubeCamera来实现镜面反射的效果。

1、示例

示例
https://ithanmang.gitee.io/threejs/home/201809/20180906/01-envMap-cubeCamera-texture.html
效果

可以看到,不仅可以反射环境贴图,也可以反射动态的物体对象,类似镜面的效果

2、实现步骤

2.1、CubeCamera 构造函数

CubeCamera( near : Number, far : Number, cubeResolution : Number )
参数
near:近裁剪距离
far:远裁剪距离
cubeResolution:分辨率

2.2、创建立方体相机
cubeCamera = new THREE.CubeCamera(0.1, 1000, 2048);
scene.add(cubeCamera);
2.3、创建镜子
let boxGeometry = new THREE.BoxGeometry(100, 100, 1);
let boxMaterial = new THREE.MeshPhongMaterial({envMap: cubeCamera.renderTarget.texture});
let box = new THREE.Mesh(boxGeometry, boxMaterial);

将镜子的材质envMap属性设置为cubeCamera.renderTarget.texture立方体相机渲染目标的纹理。

2.4、循环更新渲染目标
cubeCamera.update(renderer, scene);

注意:需要镜面反射的相机的位置,最好需要和带有反光面的对象的位置一样
cubeCamera1.position.copy(sphere.position);
cubeCamera2.position.copy(box.position);
上面是创建了两个立方体相机,一个加入球体一个加入了一面镜子,然后让这两个相机与需要反射光源的位置相同

3、示例代码

<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <link rel="icon" href="../../../three.png">
    <title>使用 CubeCamera 创建反光效果</title>
    <style>
        body {
            margin: 0;
            overflow: hidden; /* 溢出隐藏 */
        }

        #loading {
            position: fixed;
            top: 50%;
            left: 50%;
            color: #FFFFFF;
            font-size: 20px;
            margin-top: -30px;
            margin-left: -40px;
        }
    </style>
    <script src="../../libs/build/three-r93.js"></script>
    <script src="../../libs/examples/js/Detector.js"></script>
    <script src="../../libs/examples/js/libs/dat.gui.min.js"></script>
    <script src="../../libs/examples/js/libs/stats.min.js"></script>
    <script src="../../libs/examples/js/controls/OrbitControls.js"></script>
    <script src="../../libs/examples/js/loaders/GLTFLoader.js"></script>
</head>
<body>
<p id="loading">loading......</p>
<script>

    let scene, camera, renderer, controls, guiControls;
    let stats = initStats();

    /* 场景 */
    function initScene() {

        scene = new THREE.Scene();
        scene.background = new THREE.CubeTextureLoader().setPath('../../textures/cube/Bridge2/')
            .load([
                'posx.jpg',
                'negx.jpg',
                'posy.jpg',
                'negy.jpg',
                'posz.jpg',
                'negz.jpg'
            ]);

    }

    /* 相机 */
    let cubeCamera1;
    let cubeCamera2;

    function initCamera() {

        camera = new THREE.PerspectiveCamera(45, window.innerWidth / window.innerHeight, 0.1, 10000);
        camera.position.set(0, 10, 200);
        camera.lookAt(new THREE.Vector3(0, 0, 0));

        // cubeCamera1
        cubeCamera1 = new THREE.CubeCamera(0.1, 1000, 2048);
        cubeCamera2 = new THREE.CubeCamera(0.1, 1000, 2048);

    }

    /* 渲染器 */
    function initRender() {

        renderer = new THREE.WebGLRenderer({antialias: true});
        renderer.setSize(window.innerWidth, window.innerHeight);
        renderer.setPixelRatio(window.devicePixelRatio);
        renderer.gammaOutput = true;

        document.body.appendChild(renderer.domElement);

    }

    /* 灯光 */
    function initLight() {

        light = new THREE.HemisphereLight(0xbbbbff, 0x444422);
        light.position.set(0, 1, 0);
        scene.add(light);

    }

    /* 控制器 */
    function initControls() {

        /* 地图控件 */
        controls = new THREE.OrbitControls(camera);

        /* 属性参数 */

    }

    /* 调试插件 */
    function initGui() {

        guiControls = new function () {


        };

        let gui = new dat.GUI();

    }

    /* 场景中的内容 */
    let model;
    function initContent() {
        let material = new THREE.MeshPhongMaterial({envMap: cubeCamera1.renderTarget.texture});
        let material2 = new THREE.MeshPhongMaterial({envMap: cubeCamera2.renderTarget.texture});

        let sphereGeometry = new THREE.SphereGeometry(15, 100, 100);
        let boxGeometry = new THREE.BoxGeometry(300,200, 1);

        let sphere = new THREE.Mesh(sphereGeometry, material);
        sphere.position.z = -10;
        sphere.position.x = -20;

        let box = new THREE.Mesh(boxGeometry, material2);
        box.translateZ(-300);
        scene.add(box);

        let loader = new THREE.GLTFLoader();
        loader.load('../../models/gltf/DamagedHelmet/glTF/DamagedHelmet.gltf', function (gltf) {

            gltf.scene.traverse(function (child) {

                if (child.isMesh) {
                    child.scale.set(13, 13, 13);
                    child.material.envMap = scene.background;
                    child.translateX(30);
                    model = child;
                }

            });

            scene.add(gltf.scene);
            scene.add(sphere);

            cubeCamera1.position.copy(sphere.position);
            cubeCamera2.position.copy(box.position);

            removeLoading();

        });

    }

    /* 移除加载元素 */
    function removeLoading() {

        document.getElementById('loading').style.display = 'none';

    }

    /* 性能插件 */
    function initStats() {

        let stats = new Stats();

        document.body.appendChild(stats.domElement);

        return stats;

    }

    /* 窗口变动触发 */
    function onWindowResize() {

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

    }

    /* 数据更新 */
    function update() {

        stats.update();

        controls.update();

        cubeCamera1.update(renderer, scene);
        cubeCamera2.update(renderer, scene);

        if (model) {

            model.rotateZ(0.05);

        }


    }

    /* 初始化 */
    function init() {

        if (!Detector.webgl) Detector.addGetWebGLMessage();

        initScene();
        initCamera();
        initRender();
        initLight();
        initControls();
        initContent();
        initGui();

        /* 监听事件 */
        window.addEventListener('resize', onWindowResize, false);

    }

    /* 循环渲染 */
    function animate() {

        requestAnimationFrame(animate);
        renderer.render(scene, camera);
        update();

    }

    /* 初始加载 */
    (function () {
        console.log("three init start...");

        init();
        animate();

        console.log("three init end...");
    })();

</script>
</body>
</html>

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