<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Strict//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-strict.dtd">
<html xmlns="http://www.w3c.org/1999/xhtml">
<head>
<title>Polygons</title>
<style type='text/css'>
* {
margin:0;
padding:0;
}
canvas {
position:absolute;
top:50%;
left:50%;
margin-top:-200px;
margin-left:-320px;
border:1px solid #000;
}
</style>
<script type='text/javascript'>
function drawpoly(x,y,angles,radius,rotate) {
var x,y,angles,radius,rotate,angdif,cang,cx,xy,i
if (!x) x=320
if (!y) y=200
if (!angles) angles=5
if (!radius) radius=50
if (!rotate) rotate=0
angdif=360/angles
cang=90-rotate
cx=Math.cos(cang*Math.PI/180)*radius
cy=-Math.sin(cang*Math.PI/180)*radius
for (i=1;i<angles+1;i++) {
cang=i*angdif+90-rotate
ctx.beginPath()
ctx.moveTo(x+cx,y+cy)
cx=Math.cos(cang*Math.PI/180)*radius
cy=-Math.sin(cang*Math.PI/180)*radius
ctx.lineTo(x+cx,y+cy)
ctx.stroke()
}
}
function dps() {
ctx.clearRect(0,0,640,400)
for (var i=0;i<num;i++) {
drawpoly(gx[i],gy[i],gang[i],grad[i],grot[i])
grad[i]+=mrad[i]*Math.floor(Math.random()*3)
if (grad[i]<10) mrad[i]=1
else if (grad[i]>100) mrad[i]=-1
grot[i]+=mrot[i]*Math.floor(Math.random()*3)
if (grot[i]<0) mrot[i]=1
else if (grot[i]>360) mrot[i]=-1
gx[i]+=mdirx[i]*(Math.floor(Math.random()*5)+1)
gy[i]+=mdiry[i]*(Math.floor(Math.random()*5)+1)
if (gx[i]<grad[i]+5) mdirx[i]=1
else if (gx[i]>640-grad[i]-5) mdirx[i]=-1
if (gy[i]<grad[i]+5) mdiry[i]=1
else if (gy[i]>400-grad[i]-5) mdiry[i]=-1
}
setTimeout("dps()",40)
}
function load() {
ctx=document.getElementById('canvas').getContext('2d')
gang=new Array()
grad=new Array()
grot=new Array()
gx=new Array()
gy=new Array()
mdirx=new Array()
mdiry=new Array()
mrad=new Array()
mrot=new Array()
num=10
for (var i=0;i<num;i++) {
gang[i]=Math.floor(Math.random()*8)+3
grad[i]=Math.floor(Math.random()*26)+25
grot[i]=Math.floor(Math.random()*360)
gx[i]=Math.floor(Math.random()*(640-grad[i]*2))+grad[i]
gy[i]=Math.floor(Math.random()*(400-grad[i]*2))+grad[i]
mdirx[i]=Math.floor(Math.random()*2)*2-1
mdiry[i]=Math.floor(Math.random()*2)*2-1
mrad[i]=Math.floor(Math.random()*2)*2-1
mrot[i]=Math.floor(Math.random()*2)*2-1
}
dps()
}
window.onload=load
</script>
</head>
<body>
<canvas id='canvas' width='640' height='400'></canvas>
</body>
</html>