<!DOCTYPE html>
<html>
<head>
<meta charset="utf-8">
<title>Canvas</title>
<style type="text/css">
*{
margin: 0;
padding: 0;
}
html, body{
height: 100%;
}
#myCanvas{
background-color: #87CEEB;
}
</style>
</head>
<body>
<canvas id="myCanvas" width="1000" height="600">您的浏览器不支持Canvas元素</canvas>
<script type="text/javascript">
var canvas = document.getElementById("myCanvas");
var context = canvas.getContext("2d");
var deg = Math.PI/180;
var practicles = [];
for (var i = 0; i < 500; i++) {//循环生成500粒
practicles.push({
x: Math.random()*(window.innerWidth),
y: Math.random()*(window.innerHeight),
vx: Math.random()-0.5,
vy: Math.random()+0.5,
size: Math.random()*25+1,
color: "#FFF"
})
}
function timeUpdate(){
context.clearRect(0,0,window.innerWidth,window.innerHeight);//清除画布区域
var practicle;
for (var i = 0; i < 500; i++) {
var practicle = practicles[i];
practicle.x += practicles[i].vx;
practicle.y += practicles[i].vy;
if (practicle.x<0) {practicle.x=window.innerWidth}
if (practicle.x>window.innerWidth) {practicle.x=0}
if (practicle.y>window.innerHeight) {practicle.y=0}
context.beginPath();
//context.arc(practicle.x,practicle.y,practicle.size,0,Math.PI*2);
snowflake(context,3,practicle.x,practicle.y,practicle.size);
}
}
//实现科赫雪花
function snowflake(c,n,x,y,len) {
c.save();
c.translate(x,y);
c.moveTo(0,0);
leg(n);
c.rotate(-120*deg);
leg(n);
c.rotate(-120*deg);
leg(n);
c.closePath();
function leg(n) {
c.save();
if(n==0){
c.lineTo(len,0);
}else{
c.scale(1/3,1/3);
leg(n-1);
c.rotate(60*deg);
leg(n-1);
c.rotate(-120*deg);
leg(n-1);
c.rotate(60*deg);
leg(n-1);
}
c.restore();
c.translate(len,0)
}
c.stroke();
c.fillStyle = "#fff";
c.fill();
c.restore();
}
setInterval(timeUpdate,40);
</script>
</body>
</html>
最后效果:
