three.js模拟实现太阳系行星体系功能

// 初始化场景var scene = new THREE.Scene();// 初始化相机，第一个参数为摄像机视锥体垂直视野角度，第二个参数为摄像机视锥体长宽比，// 第三个参数为摄像机视锥体近端面，第四个参数为摄像机视锥体远端面var camera = new THREE.PerspectiveCamera(20, dom.clientWidth / dom.clientHeight, 1, 100000);// 设置相机位置，对应参数分别表示x，y，z位置camera.position.set(0, 0, 500);var renderer = new THREE.WebGLRenderer({      alpha: true,      antialias: true});

// 设置窗口尺寸，第一个参数为宽度，第二个参数为高度renderer.setSize(dom.clientWidth, dom.clientHeight);// 初始化控制器var orbitcontrols = new THREE.OrbitControls(camera,renderer.domElement);// 将渲染器加载到dom中dom.appendChild(renderer.domElement);

// 定义太阳材质var sunTexture = THREE.ImageUtils.loadTexture('./image/sun_bg.jpg', {}, function () {    renderer.render(scene, camera);});// 太阳以及太阳材质设定centerBall = new THREE.Mesh(new THREE.SphereGeometry(30, 30, 30), new THREE.MeshBasicMaterial({    map: sunTexture}));scene.add(centerBall);

/*** 实现球体发光* @param color 颜色的r,g和b值,比如：“123,123,123”;* @returns {Element} 返回canvas对象*/var generateSprite = function (color) {   var canvas = document.createElement('canvas');   canvas.width = 16;   canvas.height = 16;   var context = canvas.getContext('2d');   var gradient = context.createRadialGradient(canvas.width / 2, canvas.height / 2, 0, canvas.width / 2,    canvas.height / 2, canvas.width / 2);   gradient.addColorStop(0, 'rgba(' + color + ',1)');   gradient.addColorStop(0.2, 'rgba(' + color + ',1)');   gradient.addColorStop(0.4, 'rgba(' + color + ',.6)');   gradient.addColorStop(1, 'rgba(0,0,0,0)');   context.fillStyle = gradient;   context.fillRect(0, 0, canvas.width, canvas.height);   return canvas;};// 添加太阳发光效果var centerBallLite = new THREE.Sprite(new THREE.SpriteMaterial({   map: new THREE.CanvasTexture(generateSprite(sunSpriteColor)),   blending: THREE.AdditiveBlending}));centerBallLite.scale.x = centerBallLite.scale.y = centerBallLite.scale.z = sunScaleSize;scene.add(centerBallLite);

/** * 返回行星轨道的组合体 * @param starLiteSize 行星的大小 * @param starLiteRadius 行星的旋转半径 * @param rotation 行星组合体的x,y,z三个方向的旋转角度 * @param speed 行星运动速度 * @param imgUrl 行星的贴图 * @param scene 场景 * @returns {{satellite: THREE.Mesh, speed: *}} 卫星组合对象;速度*/var initSatellite = function (starLiteSize, starLiteRadius, rotation, speed, imgUrl, scene) {var track = new THREE.Mesh(new THREE.RingGeometry(starLiteRadius, starLiteRadius + 0.05, 50, 1), new THREE.MeshBasicMaterial());var centerMesh = new THREE.Mesh(new THREE.SphereGeometry(1, 1, 1), new THREE.MeshLambertMaterial()); //材质设定var starLite = new THREE.Sprite(new THREE.SpriteMaterial({     map: THREE.ImageUtils.loadTexture(imgUrl)}));starLite.scale.x = starLite.scale.y = starLite.scale.z = starLiteSize;starLite.position.set(starLiteRadius, 0, 0);var pivotPoint = new THREE.Object3D();pivotPoint.add(starLite);pivotPoint.add(track);centerMesh.add(pivotPoint);centerMesh.rotation.set(rotation.x, rotation.y, rotation.z);scene.add(centerMesh);   return {starLite: centerMesh, speed: speed};};

// 执行函数var render = function () {    renderer.render(scene, camera);    centerBall.rotation.y -= 0.01;    for (var i = 0; i < starLites.length; i++) {        starLites[i].starLite.rotation.z -= starLites[i].speed;    }    orbitcontrols.update();    requestAnimationFrame(render);}