Created
April 16, 2013 04:59
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A CodePen by Noel Delgado.
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var canvas = document.createElement('canvas'), | |
ctx = canvas.getContext('2d'), | |
W = document.body.offsetWidth, | |
H = document.body.offsetHeight, | |
COLOURS = [ "#0B9CB6", "#1A7795", "#295376", "#372E53" ], | |
A = new Node(), | |
B = new Node(); | |
document.body.appendChild( canvas ); | |
var g = ctx.createLinearGradient(0, 0, W, H), | |
intervals = 100 / COLOURS.length, | |
interval = 0; | |
for (var i = 0; i < COLOURS.length; i += 1) { | |
g.addColorStop( "." + interval, COLOURS[i] ); | |
interval += intervals; | |
} | |
function Node( x, y ) { | |
this.x = Math.random() * W; | |
this.y = Math.random() * H; | |
this.vx = Math.random() * 15; | |
this.vy = Math.random() * 15; | |
this.radius = 3; | |
this.colour = COLOURS[ ~~( Math.random() * COLOURS.length ) ]; | |
} | |
var setSize = function(){ | |
W = window.innerWidth; | |
H = window.innerHeight; | |
canvas.width = W; | |
canvas.height = H; | |
}; | |
var fillNode = function( NODE ) { | |
ctx.fillStyle = g; | |
ctx.arc( NODE.x, NODE.y, NODE.radius, Math.PI * 2, false); | |
ctx.fill(); | |
}; | |
var render = function() { | |
ctx.globalCompositeOperation = 'lighter'; | |
ctx.globalAlpha = 0.1; | |
fillNode(A); | |
fillNode(B); | |
ctx.globalAlpha = 1; | |
ctx.beginPath(); | |
ctx.lineWidth = 1; | |
ctx.moveTo( A.x, A.y ); | |
ctx.lineTo( B.x, B.y ); | |
ctx.strokeStyle = g; | |
ctx.stroke(); | |
ctx.closePath(); | |
}; | |
var update = function() { | |
A.x += A.vx; | |
A.y += A.vy; | |
B.x += B.vx; | |
B.y += B.vy; | |
if ( is_colliding(A) || is_colliding(B) ) { | |
A.colour = COLOURS[ ~~(Math.random() * COLOURS.length)]; | |
B.colour = COLOURS[ ~~(Math.random() * COLOURS.length)]; | |
} | |
}; | |
var is_colliding = function( NODE ) { | |
if (NODE.x < 0) { | |
NODE.x = 0; | |
NODE.vx *= -1; | |
return true; | |
} | |
if (NODE.x > W) { | |
NODE.x = W; | |
NODE.vx *= -1; | |
return true; | |
} | |
if (NODE.y < 0) { | |
NODE.y = 0; | |
NODE.vy *= -1; | |
return true; | |
} | |
if (NODE.y > H) { | |
NODE.y = H; | |
NODE.vy *= -1; | |
return true; | |
} | |
return false; | |
}; | |
var draw = function() { | |
requestAnimFrame(draw); | |
update(); | |
render(); | |
} | |
window.requestAnimFrame = (function() { | |
return window.requestAnimationFrame || | |
window.webkitRequestAnimationFrame || | |
window.mozRequestAnimationFrame || | |
window.oRequestAnimationFrame || | |
window.msRequestAnimationFrame || | |
function( callback ) { | |
window.setTimeout(callback, 1000 / 60); | |
} | |
})(); | |
window.addEventListener('load', setSize, false); | |
window.addEventListener('resize', setSize, false); | |
draw(); |
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
@import "compass" | |
html, body | |
width: 100% | |
height: 100% | |
background-color: #222 | |
margin: 0 | |
canvas | |
display: block |
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