Created
April 9, 2013 17:19
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A CodePen by Paul Reny.
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<canvas id="stage"></canvas> |
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/* | |
Original: http://retromodular.com/ | |
*/ | |
var glitcher = { | |
init: function () { | |
setTimeout((function () { | |
this.canvas = document.getElementById( 'stage' ); | |
this.context = this.canvas.getContext( '2d' ); | |
this.initOptions(); | |
this.resize(); | |
this.tick(); | |
}).bind(this), 100); | |
}, | |
initOptions: function () { | |
var gui = new dat.GUI(), | |
current = gui.addFolder('Current'), | |
controls = gui.addFolder('Controls'); | |
this.width = document.documentElement.offsetWidth; | |
this.height = window.innerHeight; | |
this.font = 'bold 12vw Arial'; | |
this.context.font = this.font; | |
this.text = "GLITCH"; | |
this.textWidth = (this.context.measureText(this.text)).width; | |
this.fps = 60; | |
this.channel = 0; // 0 = red, 1 = green, 2 = blue | |
this.compOp = 'lighter'; // CompositeOperation = lighter || darker || xor | |
this.phase = 0.0; | |
this.phaseStep = 0.05; //determines how often we will change channel and amplitude | |
this.amplitude = 0.0; | |
this.amplitudeBase = 2.0; | |
this.amplitudeRange = 2.0; | |
this.alphaMin = 0.8; | |
this.glitchAmplitude = 20.0; | |
this.glitchThreshold = 0.9; | |
this.scanlineBase = 40; | |
this.scanlineRange = 40; | |
this.scanlineShift = 15; | |
current.add(this, 'channel', 0, 2).listen(); | |
current.add(this, 'phase', 0, 1).listen(); | |
current.add(this, 'amplitude', 0, 5).listen(); | |
var text = controls.add(this, 'text'); | |
text.onChange((function (value) { | |
this.textWidth = (this.context.measureText(this.text)).width; | |
}).bind(this)); | |
controls.add(this, 'fps', 1, 60); | |
controls.add(this, 'phaseStep', 0, 1); | |
controls.add(this, 'alphaMin', 0, 1); | |
controls.add(this, 'amplitudeBase', 0, 5); | |
controls.add(this, 'amplitudeRange', 0, 5); | |
controls.add(this, 'glitchAmplitude', 0, 100); | |
controls.add(this, 'glitchThreshold', 0, 1); | |
controls.open(); | |
// gui.add(fizzyText, 'noiseStrength', 0, 100).listen(); | |
}, | |
tick: function () { | |
setTimeout((function () { | |
this.phase += this.phaseStep; | |
if( this.phase > 1 ) { | |
this.phase = 0.0; | |
this.channel = (this.channel === 2) ? 0 : this.channel + 1; | |
this.amplitude = this.amplitudeBase + (this.amplitudeRange * Math.random()); | |
} | |
this.render(); | |
this.tick(); | |
}).bind(this), 1000 / this.fps); | |
}, | |
render: function () { | |
var x0 = this.amplitude * Math.sin( (Math.PI * 2) * this.phase ) >> 0, | |
x1, x2, x3; | |
if( Math.random() >= this.glitchThreshold ) { | |
x0 *= this.glitchAmplitude; | |
} | |
x1 = this.width - this.textWidth >> 1; | |
x2 = x1 + x0; | |
x3 = x1 - x0; | |
this.context.clearRect( 0, 0, this.width, this.height ); | |
this.context.globalAlpha = this.alphaMin + ((1-this.alphaMin) * Math.random()); | |
switch( this.channel ) { | |
case 0: this.renderChannels(x1, x2, x3); break; | |
case 1: this.renderChannels(x2, x3, x1); break; | |
case 2: this.renderChannels(x3, x1, x2); break; | |
} | |
this.renderScanline(); | |
}, | |
renderChannels: function (x1, x2, x3) { | |
this.context.font = this.font; | |
this.context.fillStyle = "rgb(255,0,0)"; | |
this.context.fillText(this.text, x1, this.height/2); | |
this.context.globalCompositeOperation = this.compOp; | |
this.context.fillStyle = "rgb(0,255,0)"; | |
this.context.fillText(this.text, x2, this.height/2); | |
this.context.fillStyle = "rgb(0,0,255)"; | |
this.context.fillText(this.text, x3, this.height/2); | |
}, | |
renderScanline: function () { | |
var y = this.height * Math.random() >> 0, | |
o = this.context.getImageData( 0, y, this.width, 1 ), | |
d = o.data, | |
i = d.length, | |
s = this.scanlineBase + this.scanlineRange * Math.random() >> 0, | |
x = -this.scanlineShift + this.scanlineShift * 2 * Math.random() >> 0; | |
while( i-- > 0 ) { | |
d[i] += s; | |
} | |
this.context.putImageData( o, x, y ); | |
}, | |
resize: function () { | |
if(this.canvas) { | |
this.canvas.width = document.documentElement.offsetWidth; | |
this.canvas.height = window.innerHeight; | |
} | |
} | |
}; | |
glitcher.init(); | |
window.onresize = glitcher.resize; |
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@import "compass"; | |
body { background: black; overflow: hidden; } | |
img { display: none; } |
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