100 Three.js使用VideoTexture实现视频Video更新纹理

案例查看地址:http://www.wjceo.com/blog/threejs/2018-05-10/163.html

简介

既然我们可以使用canvas元素创建纹理,Three.js也给我们提供了可以实现video创建纹理的方法。我们通过Three.js提供的VideoTexture来实现创建视频纹理。

案例实现

  • 首先还是需要有一个video标签,我们将video放到左下角:
  • 然后我们通过video标签创建一个VideoTexture并赋值给materialmap即可:
//获取到video对象
var video = document.querySelector("#video");
//通过video对象实例化纹理
var texture = new THREE.VideoTexture(video);
texture.wrapS = texture.wrapT = THREE.ClampToEdgeWrapping;
texture.minFilter = THREE.LinearFilter;
material = new THREE.MeshBasicMaterial( { map: texture } );

在上面,我们设置了wrapSwrapT平铺,因为视频的格式一般都不会是标准的纹理尺寸。

案例代码



<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>Threejs使用canvas更新纹理title>
    <style type="text/css">
        html, body {
            margin: 0;
            height: 100%;
        }

        canvas {
            display: block;
        }

        #video{
            position: fixed;
            left:0;
            bottom:0;
        }
    style>
head>

<body onload="draw();">
<video id="video" autoplay controls >
    <source src="/lib/textures/sintel.ogv" type='video/ogg; codecs="theora, vorbis"'>
    <source src="/lib/textures/sintel.mp4" type='video/mp4; codecs="avc1.42E01E, mp4a.40.2"'>
video>
body>
<script src="https://cdn.bootcss.com/three.js/91/three.min.js">script>
<script src="/lib/js/controls/OrbitControls.js">script>
<script src="https://cdn.bootcss.com/stats.js/r17/Stats.min.js">script>
<script src="https://cdn.bootcss.com/dat-gui/0.7.1/dat.gui.min.js">script>
<script src="/lib/js/Detector.js">script>

<script>
    var renderer, camera, scene, gui, light, stats, controls;

    function initRender() {
        renderer = new THREE.WebGLRenderer({antialias: true});
        renderer.setPixelRatio(window.devicePixelRatio);
        renderer.setSize(window.innerWidth, window.innerHeight);
        renderer.setClearColor(0xeeeeee);
        renderer.shadowMap.enabled = true;
        //告诉渲染器需要阴影效果
        document.body.appendChild(renderer.domElement);
    }

    function initCamera() {
        camera = new THREE.PerspectiveCamera(45, window.innerWidth / window.innerHeight, 0.1, 1000);
        camera.position.set(0, 0, 15 );
    }

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

    //初始化dat.GUI简化试验流程
    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 initLight() {
        scene.add(new THREE.AmbientLight(0x444444));

        light = new THREE.DirectionalLight(0xffffff);
        light.position.set(0, 20, 20 );

        light.castShadow = true;
        light.shadow.camera.top = 10;
        light.shadow.camera.bottom = -10;
        light.shadow.camera.left = -10;
        light.shadow.camera.right = 10;

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

        scene.add(light);
    }

    function initModel() {

        //辅助工具
        var helper = new THREE.AxesHelper(50);
        scene.add(helper);

        //添加立方体
        var geometry = new THREE.BoxBufferGeometry( 10, 5, 5 );

        //获取到video对象
        var video = document.querySelector("#video");
        //通过video对象实例化纹理
        var texture = new THREE.VideoTexture(video);
        texture.wrapS = texture.wrapT = THREE.ClampToEdgeWrapping;
        texture.minFilter = THREE.LinearFilter;
        material = new THREE.MeshBasicMaterial( { map: texture } );

        scene.add(new THREE.Mesh(geometry, material));
    }

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

    function initControls() {

        controls = new THREE.OrbitControls(camera, renderer.domElement);
        //设置控制器的中心点
        //controls.target.set( 0, 5, 0 );
        // 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;
        controls.autoRotateSpeed = 0.5;
        //设置相机距离原点的最远距离
        controls.minDistance = 1;
        //设置相机距离原点的最远距离
        controls.maxDistance = 2000;
        //是否开启右键拖拽
        controls.enablePan = true;
    }

    function render() {

    }

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

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

    }

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

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

        controls.update();

        renderer.render(scene, camera);

        requestAnimationFrame(animate);
    }

    function draw() {
        //兼容性判断
        if (!Detector.webgl) Detector.addGetWebGLMessage();

        initGui();
        initRender();
        initScene();
        initCamera();
        initLight();
        initModel();
        initControls();
        initStats();

        animate();
        window.onresize = onWindowResize;
    }


script>
html>

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