<link href="//netdna.bootstrapcdn.com/bootstrap/3.0.0/css/bootstrap.min.css" rel="stylesheet" id="bootstrap-css">
<script src="//netdna.bootstrapcdn.com/bootstrap/3.0.0/js/bootstrap.min.js"></script>
<script src="//code.jquery.com/jquery-1.11.1.min.js"></script>
<!------ Include the above in your HEAD tag ---------->
<canvas id="canvas"></canvas>
html {
height: 100%;
}
body{
padding: 0; margin: 0;
min-height: 400px; height: 100%;
width: 100%;
overflow: hidden;
}
// shim layer with setTimeout fallback
window.requestAnimFrame = (function(){
return window.requestAnimationFrame ||
window.webkitRequestAnimationFrame ||
window.mozRequestAnimationFrame ||
window.oRequestAnimationFrame ||
window.msRequestAnimationFrame ||
function( callback ){
window.setTimeout(callback, 1000 / 60);
};
})();
var canvas = document.getElementById("canvas"),
ctx = canvas.getContext("2d"),
W = window.innerWidth,
H = window.innerHeight,
circles = [];
canvas.width = W;
canvas.height = H;
//Random Circles creator
function create() {
//Place the circles at the center
this.x = W/2;
this.y = H/2;
//Random radius between 2 and 6
this.radius = 2 + Math.random()*3;
//Random velocities
this.vx = -5 + Math.random()*10;
this.vy = -5 + Math.random()*10;
//Random colors
this.r = Math.round(Math.random())*255;
this.g = Math.round(Math.random())*255;
this.b = Math.round(Math.random())*255;
}
for (var i = 0; i < 500; i++) {
circles.push(new create());
}
function draw() {
//Fill canvas with black color
ctx.globalCompositeOperation = "source-over";
ctx.fillStyle = "rgba(0,0,0,0.15)";
ctx.fillRect(0, 0, W, H);
//Fill the canvas with circles
for(var j = 0; j < circles.length; j++){
var c = circles[j];
//Create the circles
ctx.beginPath();
ctx.arc(c.x, c.y, c.radius, 0, Math.PI*2, false);
ctx.fillStyle = "rgba("+c.r+", "+c.g+", "+c.b+", 0.5)";
ctx.fill();
c.x += c.vx;
c.y += c.vy;
c.radius -= .02;
if(c.radius < 0)
circles[j] = new create();
}
}
function animate() {
requestAnimFrame(animate);
draw();
}
$(document).ready(function() {
animate();
});
