小生最近学习three.js，将three.js官网提供的网站实例翻译翻译，共同学习。接下来翻译一下 webgl_video_panorama_equirectangular.html
运行结果https://threejs.org/examples/#webgl_video_panorama_equirectangular
<!DOCTYPE html>
<html lang="en">
<head>
<title>three.js webgl - equirectangular video panorama</title>
<meta charset="utf-8">
<meta name="viewport" content="width=device-width, user-scalable=no, minimum-scale=1.0, maximum-scale=1.0">
<style>
body {
background-color: #000000;
margin: 0px;
overflow: hidden;
}
#info {
position: absolute;
top: 0px; width: 100%;
color: #ffffff;
padding: 5px;
font-family:Monospace;
font-size:13px;
font-weight: bold;
text-align:center;
}
a {
color: #ffffff;
}
</style>
</head>
<body>
<div id="container"></div>
<script src="../build/three.js"></script>
<script>
//原理：通过three.js建立一个球模型,将视频贴到球模型上,通过矩阵变换将视频贴到模型内部,观察点不动,通过鼠标拖动,改变相机的位置来实现全景视频的观看。
//当然需要将模型添加到场景中，通过渲染器不断的渲染
var camera, scene, renderer;
var texture_placeholder,//多余代码
isUserInteracting = false,//鼠标按下的标志，开始鼠标没有按下为false
onMouseDownMouseX = 0, onMouseDownMouseY = 0,
lon = 0,//记录水平方向的偏角,即水平角
onMouseDownLon = 0,//多余代码
lat = 0,//记录竖直方向的偏角,即仰俯角
onMouseDownLat = 0,//多余代码
phi = 0,//在three.js中 phi代表与xoy平面的夹角,即仰俯角
theta = 0, //theta代表与xoy平面的夹角, 即水平角
distance = 500,//观察点到相机的距离,即球半径
onPointerDownPointerX = 0,//记录鼠标按下瞬间的屏幕x值
onPointerDownPointerY = 0,//记录鼠标按下瞬间的屏幕x值
onPointerDownLon = 0,//记录上一次鼠标水平移动的角度.
onPointerDownLat = 0;//记录上一次鼠标竖直移动的角度.
init();
animate();
function init() {
var container, mesh;
container = document.getElementById( 'container' );
camera = new THREE.PerspectiveCamera(75, window.innerWidth / window.innerHeight, 1, 1100);//透视投影,即远景相机,模仿人眼
camera.target = new THREE.Vector3( 0, 0, 0 );//初始化相机观察点
scene = new THREE.Scene();//初始化场景
var geometry = new THREE.SphereBufferGeometry( 500, 60, 40 );//建立半径为500,水平垂直分割面分别为60,40的缓冲球面
geometry.scale( -1, 1, 1 );//进行缩放，进行矩阵变换,将视频贴在球内表面
var video = document.createElement( 'video' );
video.width = 640;
video.height = 360;
video.loop = true;//视频是否循环
video.muted = true;//是否关闭音频
video.src = "textures/pano.webm";
video.setAttribute( 'webkit-playsinline', 'webkit-playsinline' );
video.play();
var texture = new THREE.VideoTexture( video );//视频纹理
texture.minFilter = THREE.LinearFilter;//纹理在缩小时的过滤方式,默认THREE.LinearMipMapNearestFilter选择最临近的mip层，并执行线性过滤
texture.format = THREE.RGBFormat;//像素数据的颜色格式, 默认为THREE.RGBAFormat,还有以下可选参数
//THREE.AlphaFormat = 1019; //GL_ALPHA Alpha 值
//THREE.RGBFormat = 1020; //Red, Green, Blue 三原色值
//THREE.RGBAFormat = 1021; //Red, Green, Blue 和 Alpha 值
//THREE.LuminanceFormat = 1022; //灰度值
//THREE.LuminanceAlphaFormat = 1023; //灰度值和 Alpha 值
var material = new THREE.MeshBasicMaterial({ map: texture });//基础网孔材料
mesh = new THREE.Mesh( geometry, material );
scene.add( mesh );
renderer = new THREE.WebGLRenderer();//webGL渲染器
renderer.setPixelRatio(window.devicePixelRatio);//返回当前设备的像素比
renderer.setSize( window.innerWidth, window.innerHeight );
container.appendChild( renderer.domElement );
document.addEventListener( 'mousedown', onDocumentMouseDown, false );
document.addEventListener( 'mousemove', onDocumentMouseMove, false );
document.addEventListener( 'mouseup', onDocumentMouseUp, false );
document.addEventListener( 'wheel', onDocumentMouseWheel, false );
//
window.addEventListener( 'resize', onWindowResize, false );
}
function onWindowResize() {
//自适应
camera.aspect = window.innerWidth / window.innerHeight;
camera.updateProjectionMatrix();
renderer.setSize( window.innerWidth, window.innerHeight );
}
//鼠标按下
function onDocumentMouseDown( event ) {
event.preventDefault();//阻止默认行为
isUserInteracting = true;
onPointerDownPointerX = event.clientX;
onPointerDownPointerY = event.clientY;
onPointerDownLon = lon;
onPointerDownLat = lat;
}
function onDocumentMouseMove( event ) {
if ( isUserInteracting === true ) {
//按下并移动,计算移动的角度
lon = ( onPointerDownPointerX - event.clientX ) * 0.1 + onPointerDownLon;
lat = ( onPointerDownPointerY -event.clientY ) * 0.1 + onPointerDownLat;
}
}
//鼠标抬起
function onDocumentMouseUp( event ) {
isUserInteracting = false;
}
//鼠标滚轮操作,改变相机位置
function onDocumentMouseWheel( event ) {
distance += event.deltaY * 0.05;
}
function animate() {
requestAnimationFrame( animate );
update();
}
function update() {
//将角度转化为弧度
lat = Math.max( - 85, Math.min( 85, lat ) );
phi = THREE.Math.degToRad( 90 - lat );
theta = THREE.Math.degToRad( lon );
//球面坐标计算公式,相当于相机在球面移动,观察点不动
camera.position.x = distance * Math.sin( phi ) * Math.cos( theta );
camera.position.y = distance * Math.cos( phi );
camera.position.z = distance * Math.sin( phi ) * Math.sin( theta );
camera.lookAt( camera.target );
/*
// distortion
camera.position.copy( camera.target ).negate();
*/
//渲染
renderer.render( scene, camera );
}
