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@conspirator
Created February 12, 2012 21:06
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I 'borrowed' this JavaScript from a page, and am tweaking it a bit. Pretty cool effect.
<html>
<head>
<title>Pixie</title>
</head>
<body style="background:#000;">
<canvas id="pixie" style="display:block;margin:50px auto;width:480px;"></canvas>
<script src="pixie.js"></script>
<script>
window.onload = function() {
canvas = document.getElementById('pixie');
canvas.setAttribute("width",WIDTH);
canvas.setAttribute("height",HEIGHT);
con = canvas.getContext('2d');
for(var i = 0; i < 100; i++) {
pxs[i] = new Circle();
pxs[i].reset();
}
setInterval(draw,rint);
}
</script>
</body>
</html>
var canvas, con, g, pxs = new Array(), rint = 60,
WIDTH = 480,
HEIGHT = 580;
function draw() {
con.clearRect(0,0,WIDTH,HEIGHT);
for(var i = 0; i < pxs.length; i++) {
pxs[i].fade();
pxs[i].move();
pxs[i].draw();
}
}
function Circle() {
this.color = '49,102,152'; // '77,101,181'
this.s = {ttl:8000, xmax:5, ymax:2, rmax:10, rt:1, xdef:960, ydef:540, xdrift:4, ydrift: 4, random:true, blink:true};
this.reset = function() {
this.x = (this.s.random ? WIDTH*Math.random() : this.s.xdef);
this.y = (this.s.random ? HEIGHT*Math.random() : this.s.ydef);
this.r = ((this.s.rmax-1)*Math.random()) + 1;
this.dx = (Math.random()*this.s.xmax) * (Math.random() < .5 ? -1 : 1);
this.dy = (Math.random()*this.s.ymax) * (Math.random() < .5 ? -1 : 1);
this.hl = (this.s.ttl/rint)*(this.r/this.s.rmax);
this.rt = Math.random()*this.hl;
this.s.rt = Math.random()+1;
this.stop = Math.random()*.2+.4;
this.s.xdrift *= Math.random() * (Math.random() < .5 ? -1 : 1);
this.s.ydrift *= Math.random() * (Math.random() < .5 ? -1 : 1);
}
this.fade = function() {
this.rt += this.s.rt;
}
this.draw = function() {
if(this.s.blink && (this.rt <= 0 || this.rt >= this.hl)) this.s.rt = this.s.rt*-1;
else if(this.rt >= this.hl) this.reset();
var newo = 1-(this.rt/this.hl);
con.beginPath();
con.arc(this.x,this.y,this.r,0,Math.PI*2,true);
con.closePath();
var cr = this.r*newo;
g = con.createRadialGradient(this.x,this.y,0,this.x,this.y,(cr <= 0 ? 1 : cr));
g.addColorStop(0.0, 'rgba(255,255,255,'+newo+')');
g.addColorStop(this.stop, 'rgba('+this.color+','+(newo*.6)+')');
g.addColorStop(1.0, 'rgba('+this.color+',0)');
con.fillStyle = g;
con.fill();
}
this.move = function() {
this.x += (this.rt/this.hl)*this.dx;
this.y += (this.rt/this.hl)*this.dy;
if(this.x > WIDTH || this.x < 0) this.dx *= -1;
if(this.y > HEIGHT || this.y < 0) this.dy *= -1;
}
this.getX = function() { return this.x; }
this.getY = function() { return this.y; }
}
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