介绍
由于实现了下雨的效果，实现下雪的效果就简单多了。首先就是更换一张图片，然后在渲染的时候，降低y轴的速度，就实现了下雪的效果。
案例代码
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<title>Title</title>
<style type="text/css">
html, body {
margin: 0;
height: 100%;
}
canvas {
display: block;
}
</style>
</head>
<body onload="draw();">
</body>
<script src="https://johnson2heng.github.io/three.js-demo/lib/three.js"></script>
<script src="https://johnson2heng.github.io/three.js-demo/lib/js/controls/OrbitControls.js"></script>
<script src="https://johnson2heng.github.io/three.js-demo/lib/js/libs/stats.min.js"></script>
<script src="https://johnson2heng.github.io/three.js-demo/lib/js/libs/dat.gui.min.js"></script>
<script>
var renderer;
function initRender() {
renderer = new THREE.WebGLRenderer({antialias: true});
renderer.setClearColor(new THREE.Color(0xffffff)); //设置背景颜色
renderer.setSize(window.innerWidth, window.innerHeight);
document.body.appendChild(renderer.domElement);
}
var camera;
function initCamera() {
camera = new THREE.PerspectiveCamera(45, window.innerWidth / window.innerHeight, 1, 200);
camera.position.set(0, 20, 100);
camera.lookAt(new THREE.Vector3(0, 30, 0));
}
var scene;
function initScene() {
scene = new THREE.Scene();
}
var light;
function initLight() {
scene.add(new THREE.AmbientLight(0x404040));
light = new THREE.DirectionalLight(0xffffff);
light.position.set(1, 1, 1);
scene.add(light);
}
function initModel() {
//轴辅助 （每一个轴的长度）
var object = new THREE.AxesHelper(500);
//scene.add(object);
}
//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 = false;
//设置相机距离原点的最远距离
controls.minDistance = 20;
//设置相机距离原点的最远距离
controls.maxDistance = 10000;
//是否开启右键拖拽
controls.enablePan = true;
}
//生成gui设置配置项
var gui;
var cloud;
function initGui() {
//声明一个保存需求修改的相关数据的对象
gui = {
"size": 2,
"transparent": true,
"opacity": 0.6,
"vertexColors": true,
"color": 0xffffff,
"sizeAttenuation": true,
"rotateSystem": false,
redraw: function () {
if (cloud) {
scene.remove(cloud);
}
createParticles(gui.size, gui.transparent, gui.opacity, gui.vertexColors, gui.sizeAttenuation, gui.color);
//设置是否自动旋转
controls.autoRotate = gui.rotateSystem;
}
};
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）gui.add(controls, 'size', 0, 10).onChange(controls.redraw);
datGui.add(gui, 'size',0.1,10).onChange(gui.redraw);
datGui.add(gui, 'transparent').onChange(gui.redraw);
datGui.add(gui, 'opacity', 0, 1).onChange(gui.redraw);
datGui.add(gui, 'vertexColors').onChange(gui.redraw);
datGui.addColor(gui, 'color').onChange(gui.redraw);
datGui.add(gui, 'sizeAttenuation').onChange(gui.redraw);
datGui.add(gui, 'rotateSystem').onChange(gui.redraw);
gui.redraw();
}
//生成粒子的方法
function createParticles(size, transparent, opacity, vertexColors, sizeAttenuation, color) {
var texture = new THREE.TextureLoader().load("./snow.png");
//存放粒子数据的网格
var geom = new THREE.Geometry();
//样式化粒子的THREE.PointCloudMaterial材质
var material = new THREE.PointsMaterial({
size: size,
transparent: transparent,
opacity: opacity,
vertexColors: vertexColors,
sizeAttenuation: sizeAttenuation,
color: color,
map:texture,
depthTest: false //设置解决透明度有问题的情况
});
var range = 120;
for (var i = 0; i < 15000; i++) {
//添加顶点的坐标
var particle = new THREE.Vector3(Math.random() * range - range / 2, Math.random() * range - range / 2, Math.random() * range - range / 2);
particle.velocityY = 0.1 + Math.random() / 5;
particle.velocityX = (Math.random() - 0.5) / 3;
geom.vertices.push(particle);
var color = new THREE.Color(0xffffff);
//.setHSL ( h, s, l ) h — 色调值在0.0和1.0之间 s — 饱和值在0.0和1.0之间 l — 亮度值在0.0和1.0之间。 使用HSL设置颜色。
//随机当前每个粒子的亮度
//color.setHSL(color.getHSL().h, color.getHSL().s, Math.random() * color.getHSL().l);
geom.colors.push(color);
}
//生成模型，添加到场景当中
cloud = new THREE.Points(geom, material);
cloud.verticesNeedUpdate = true;
scene.add(cloud);
}
function render() {
//产生雨滴动画效果
var vertices = cloud.geometry.vertices;
vertices.forEach(function (v) {
v.y = v.y - (v.velocityY);
v.x = v.x - (v.velocityX)*.5;
if (v.y <= -60) v.y = 60;
if (v.x <= -20 || v.x >= 20) v.velocityX = v.velocityX * -1;
});
//设置实时更新网格的顶点信息
cloud.geometry.verticesNeedUpdate = true;
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
controls.update();
render();
//更新性能插件
stats.update();
requestAnimationFrame(animate);
}
function draw() {
initRender();
initScene();
initCamera();
initLight();
initModel();
initControls();
initStats();
initGui();
animate();
window.onresize = onWindowResize;
}
</script>
</html>
