mirror of
https://github.com/Tonejs/Tone.js
synced 2024-11-17 00:58:09 +00:00
72 lines
2 KiB
JavaScript
72 lines
2 KiB
JavaScript
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///////////////////////////////////////////////////////////////////////////////
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//
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// BIT CRUSHER
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//
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// downsample incoming signal
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// inspiration from https://github.com/jaz303/bitcrusher/blob/master/index.js
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///////////////////////////////////////////////////////////////////////////////
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define(["core/Tone"], function(Tone){
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//@param {number=} bits
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//@param {number=} frequency
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//@param {number=} channels
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Tone.BitCrusher = function(bits, frequency, channels){
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Tone.call(this);
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//the math
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this.bits = this.defaultArg(bits, 8);
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this.frequency = this.defaultArg(frequency, .5);
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this.step = 2 * Math.pow(0.5, this.bits);
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this.invStep = 1/this.step;
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this.phasor = 0;
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this.last = 0;
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this.channels = this.defaultArg(channels, 1);
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//the node
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this.crusher = this.context.createScriptProcessor(this.bufferSize, this.channels, this.channels);
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this.crusher.onaudioprocess = this.audioprocess.bind(this);
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//connect it up
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this.chain(this.input, this.crusher, this.output);
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}
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Tone.extend(Tone.BitCrusher);
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Tone.BitCrusher.prototype.audioprocess = function(event){
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var bufferSize = this.crusher.bufferSize;
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var phasor = this.phasor;
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var freq = this.frequency;
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var invStep = this.invStep;
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var floor = Math.floor;
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var last = this.last;
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var step = this.step;
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var channel = 0;
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var input = event.inputBuffer.getChannelData(channel);
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var output = event.outputBuffer.getChannelData(channel);
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for (var i = 0, len = output.length; i < len; i++) {
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phasor += freq;
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if (phasor >= 1) {
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phasor -= 1;
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last = step * floor((input[i] * invStep) + 0.5);
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}
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output[i] = last;
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}
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/*for (var channel = 0; channel < channels; channel++){
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}*/
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this.phasor = phasor;
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this.last = last;
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}
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Tone.BitCrusher.prototype.setBits = function(bits){
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this.bits = bits;
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this.step = 2 * Math.pow(0.5, this.bits);
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this.invStep = 1/this.step;
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}
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Tone.BitCrusher.prototype.setFrequency = function(freq){
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this.frequency = freq;
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}
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return Tone.BitCrusher;
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});
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