PLY全称（Polygon or Stanford Triangle Format）多边形或三角形格式，可以有效地保存和加载简单、静态的3D内容,支持二进制和ascii格式。
可以存储顶点位置、颜色、法线和uv坐标，不能保存纹理。
示例：
http://ithanmang.com/threeJs/home/201808/20180829/04-generate-points.html
① 导入 ply 格式的模型
引入PLYLoader.js文件
<script src="../../libs/examples/js/loaders/PLYLoader.js"></script>加载ply的文件
let loader = new THREE.PLYLoader();
loader.load('../../models/ply/test.ply', function (obj) {
console.log(obj);
}查看回调函数中打印输出的信息，可以看到是一个BufferGeometry缓存几何对象，因为ply格式的文件，只能保存模型的几何数据。
② 通过 导入的几何数据创建粒子系统
通过加载ply格式的文件，可以直接创建THREE.Points粒子系统对象
let mateial = new THREE.PointsMaterial({
color: 0xffffff,
size: 0.05,
opacity: 0.5,
transparent: true,
blending: THREE.AdditiveBlending,
map: generateSprite()
});
points = new THREE.Points(loadGeometry, mateial);
points.translateZ(-5);
points.translateY(2);
scene.add(points);generateSprite()用于生成粒子的纹理
③ 示例代码
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<title>从加载进来的模型生成粒子系统</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/PLYLoader.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.Color(0x050505);
}
/* 相机 */
function initCamera() {
camera = new THREE.PerspectiveCamera(45, window.innerWidth / window.innerHeight, 0.1, 10000);
camera.position.set(-10, 13, 25);
camera.lookAt(new THREE.Vector3(0, 0, 0));
}
/* 渲染器 */
function initRender() {
renderer = new THREE.WebGLRenderer({antialias: true});
renderer.setSize(window.innerWidth, window.innerHeight);
document.body.appendChild(renderer.domElement);
}
/* 灯光 */
function initLight() {
scene.add(new THREE.AmbientLight(0x0c0c0c));
let spotLight = new THREE.SpotLight(0xffffff);
spotLight.position.set(-100, -100, -100);
let spotLight2 = new THREE.SpotLight(0xffffff);
spotLight2.position.set(100, 100, 100);
scene.add(spotLight);
scene.add(spotLight2);
}
/* 控制器 */
function initControls() {
controls = new THREE.OrbitControls(camera, renderer.domElement);
/* 属性参数默认 */
}
/* 调试插件 */
function initGui() {
guiControls = new function () {
};
let controls = new dat.GUI({width: 300});
}
/* 场景中的内容 */
let loadGeometry;
let points;
function initContent() {
let loader = new THREE.PLYLoader();
loader.load('../../models/ply/test.ply', function (obj) {
console.log(obj);
obj.computeVertexNormals();
loadGeometry = obj.clone();
var material = new THREE.MeshStandardMaterial({color: 0x7FFF00, flatShading: true});
var mesh = new THREE.Mesh(loadGeometry, material);
mesh.translateZ(5);
mesh.translateY(2);
scene.add(mesh);
let mateial = new THREE.PointsMaterial({
color: 0xffffff,
size: 0.05,
opacity: 0.5,
transparent: true,
blending: THREE.AdditiveBlending,
map: generateSprite()
});
points = new THREE.Points(loadGeometry, mateial);
points.translateZ(-5);
points.translateY(2);
scene.add(points);
document.getElementById('loading').style.display = 'none';
});
}
// from THREE.js examples
function generateSprite() {
let canvas = document.createElement('canvas');
canvas.width = 16;
canvas.height = 16;
let context = canvas.getContext('2d');
let gradient = context.createRadialGradient(canvas.width / 2, canvas.height / 2, 0, canvas.width / 2, canvas.height / 2, canvas.width / 2);
gradient.addColorStop(0, 'rgba(255,255,255,1)');
gradient.addColorStop(0.2, 'rgba(0,255,255,1)');
gradient.addColorStop(0.4, 'rgba(0,0,64,1)');
gradient.addColorStop(1, 'rgba(0,0,0,1)');
context.fillStyle = gradient;
context.fillRect(0, 0, canvas.width, canvas.height);
let texture = new THREE.Texture(canvas);
texture.needsUpdate = true;
return texture;
}
/* 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();
}
/* 初始化 */
function init() {
initScene();
initCamera();
initRender();
initLight();
initControls();
initContent();
initGui();
/* 监听事件 */
document.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 send...");
})();
</script>
</body>
</html>