79 Three.js 使用导入的模型生成粒子
简介
前几节我已经将现在一些经常使用的模型导入的方法。之前也接触粒子的创建。这个案例是把两者结合起来，通过导入模型获得几何体的数据，然后创建粒子。
实现案例
案例查看地址：http://www.wjceo.com/blog/threejs/2018-03-25/139.html
- 首先，引入script加载器，这里的案例是使用的
STL格式的文件生成，所以，引入STL文件加载器
<script src="/lib/js/loaders/STLLoader.js">script>- 然后，获取到模型的几何体，然后创建点云。
var loader = new THREE.STLLoader();
loader.load("/lib/assets/models/SolidHead_2_lowPoly_42k.stl", function (geometry) {
//创建纹理
var material = new THREE.PointsMaterial({
color: 0xffffff,
size: 0.4,
opacity: 0.6,
transparent: true,
blending: THREE.AdditiveBlending,
depthTest: false,
map: generateSprite()
});
var mesh = new THREE.Points(geometry, material);
mesh.rotation.x = -0.5 * Math.PI; //将模型摆正
mesh.scale.set(0.1, 0.1, 0.1); //缩放
geometry.center(); //居中显示
scene.add(mesh);
});案例代码
<html lang="en">
<head>
<meta charset="UTF-8">
<title>Titletitle>
<style type="text/css">
html, body {
margin: 0;
height: 100%;
}
canvas {
display: block;
}
style>
head>
<body onload="draw();">
body>
<script src="/lib/three.js">script>
<script src="/lib/js/loaders/STLLoader.js">script>
<script src="/lib/js/controls/OrbitControls.js">script>
<script src="/lib/js/libs/stats.min.js">script>
<script src="/lib/js/libs/dat.gui.min.js">script>
<script>
var renderer;
function initRender() {
renderer = new THREE.WebGLRenderer({antialias:true});
renderer.setSize(window.innerWidth, window.innerHeight);
//告诉渲染器需要阴影效果
renderer.setClearColor(0x000000);
document.body.appendChild(renderer.domElement);
}
var camera;
function initCamera() {
camera = new THREE.PerspectiveCamera(45, window.innerWidth/window.innerHeight, 0.1, 1000);
camera.position.set(0, 20, 25);
camera.lookAt(new THREE.Vector3(0,0,0));
}
var scene;
function initScene() {
scene = new THREE.Scene();
}
//初始化dat.GUI简化试验流程
var gui;
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）
}
var light;
function initLight() {
scene.add(new THREE.AmbientLight(0x444444));
light = new THREE.PointLight(0xffffff);
light.position.set(0,50,50);
//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);
var loader = new THREE.STLLoader();
loader.load("/lib/assets/models/SolidHead_2_lowPoly_42k.stl", function (geometry) {
//创建纹理
var material = new THREE.PointsMaterial({
color: 0xffffff,
size: 0.4,
opacity: 0.6,
transparent: true,
blending: THREE.AdditiveBlending,
depthTest: false,
map: generateSprite()
});
var mesh = new THREE.Points(geometry, material);
mesh.rotation.x = -0.5 * Math.PI; //将模型摆正
mesh.scale.set(0.1, 0.1, 0.1); //缩放
geometry.center(); //居中显示
scene.add(mesh);
});
}
//使用canvas生成粒子的纹理
function generateSprite() {
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(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);
var texture = new THREE.Texture(canvas);
texture.needsUpdate = true;
return texture;
}
//初始化性能插件
var stats;
function initStats() {
stats = new Stats();
document.body.appendChild(stats.dom);
}
//用户交互插件 鼠标左键按住旋转，右键按住平移，滚轮缩放
var controls;
function initControls() {
controls = new THREE.OrbitControls( camera, renderer.domElement );
// 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 = true;
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 = 200;
//是否开启右键拖拽
controls.enablePan = true;
}
function render() {
renderer.render( scene, camera );
}
//窗口变动触发的函数
function onWindowResize() {
camera.aspect = window.innerWidth / window.innerHeight;
camera.updateProjectionMatrix();
render();
renderer.setSize( window.innerWidth, window.innerHeight );
}
function animate() {
//更新控制器
render();
//更新性能插件
stats.update();
controls.update();
requestAnimationFrame(animate);
}
function draw() {
initGui();
initRender();
initScene();
initCamera();
initLight();
initModel();
initControls();
initStats();
animate();
window.onresize = onWindowResize;
}
script>
html>