Created
November 6, 2013 13:54
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| <!DOCTYPE html> | |
| <html> | |
| <head> | |
| <meta charset=utf-8 /> | |
| <title>JS Bin</title> | |
| </head> | |
| <body> | |
| <canvas id="canvas" width="480" height="340"></canvas> | |
| </body> | |
| </html> |
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| var canvas = document.getElementById("canvas"); | |
| var ctx = canvas.getContext("2d"); | |
| var width = 480; | |
| var height = 340; | |
| var size = 4; | |
| var speed = 6; | |
| var interval = Math.floor(1000 / 24); | |
| var particle; | |
| var updateParticle = function(){ | |
| particle.x = particle.x + particle.dx; | |
| particle.y = particle.y + particle.dy; | |
| if(particle.x < 0 || particle.x > width){ | |
| particle.dx = particle.dx * -1; | |
| } | |
| if(particle.y < 0 || particle.y > height){ | |
| particle.dy = particle.dy * -1; | |
| } | |
| }; | |
| var draw = function(){ | |
| if(ctx !== null){ | |
| ctx.globalCompositeOperation = "source-over"; | |
| ctx.fillStyle = "rgba(0, 8, 16, 0.4)"; | |
| ctx.fillRect(0, 0, width, height); | |
| ctx.globalCompositeOperation = "lighter"; | |
| ctx.beginPath(); | |
| ctx.arc(particle.x, particle.y, particle.size, 0, 2 * Math.PI); | |
| ctx.closePath(); | |
| ctx.fillStyle = particle.color; | |
| ctx.fill(); | |
| } | |
| }; | |
| var update = function(){ | |
| updateParticle(); | |
| draw(); | |
| setTimeout(update, interval); | |
| }; | |
| var initialize = function(){ | |
| particle = { | |
| x: Math.floor(Math.random() * width), | |
| y: Math.floor(Math.random() * height), | |
| dx: speed, | |
| dy: speed, | |
| size: size, | |
| color: "rgb(00, 150, 221)" | |
| }; | |
| setTimeout(update, interval); | |
| }; | |
| initialize(); |
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