519 lines
No EOL
15 KiB
JavaScript
519 lines
No EOL
15 KiB
JavaScript
'use strict';
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(function () {
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var Dancer = function () {
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this.audioAdapter = new Dancer.adapters.webaudio(this);
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this.events = {};
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this.sections = [];
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this.bind('update', update);
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};
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Dancer.version = 'X.X.X';
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Dancer.adapters = {};
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Dancer.prototype = {
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load: function (source, boost) {
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this.audio = this.audioAdapter.load(source, boost);
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return this;
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},
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/* Actions */
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createKick: function (options) {
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return new Dancer.Kick(this, options);
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},
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bind: function (name, callback) {
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if (!this.events[name]) {
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this.events[name] = [];
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}
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this.events[name].push(callback);
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return this;
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},
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unbind: function (name) {
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if (this.events[name]) {
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delete this.events[name];
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}
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return this;
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},
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trigger: function (name) {
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var _this = this;
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if (this.events[name]) {
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this.events[name].forEach(function (callback) {
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callback.call(_this);
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});
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}
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return this;
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},
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// Returns the magnitude of a frequency or average over a range of frequencies
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getFrequency: function (freq, endFreq) {
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var sum = 0;
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if (endFreq !== undefined) {
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for (var i = freq; i <= endFreq; i++) {
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sum += this.getSpectrum()[i];
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}
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return sum / (endFreq - freq + 1);
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} else {
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return this.getSpectrum()[freq];
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}
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},
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getWaveform: function () {
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return this.audioAdapter.getWaveform();
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},
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getSpectrum: function () {
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return this.audioAdapter.getSpectrum();
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},
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/* Sections */
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after: function (time, callback) {
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var _this = this;
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this.sections.push({
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condition: function () {
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return _this.getTime() > time;
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},
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callback: callback
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});
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return this;
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},
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before: function (time, callback) {
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var _this = this;
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this.sections.push({
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condition: function () {
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return _this.getTime() < time;
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},
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callback: callback
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});
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return this;
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},
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between: function (startTime, endTime, callback) {
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var _this = this;
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this.sections.push({
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condition: function () {
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return _this.getTime() > startTime && _this.getTime() < endTime;
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},
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callback: callback
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});
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return this;
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},
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onceAt: function (time, callback) {
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var
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_this = this,
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thisSection = null;
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this.sections.push({
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condition: function () {
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return _this.getTime() > time && !this.called;
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},
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callback: function () {
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callback.call(this);
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thisSection.called = true;
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},
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called: false
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});
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// Baking the section in the closure due to callback's this being the dancer instance
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thisSection = this.sections[this.sections.length - 1];
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return this;
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}
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};
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function update() {
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for (var i in this.sections) {
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if (this.sections[i].condition && this.sections[i].condition())
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this.sections[i].callback.call(this);
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}
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}
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window.Dancer = Dancer;
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})();
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(function (Dancer) {
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var CODECS = {
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'mp3': 'audio/mpeg;',
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'ogg': 'audio/ogg; codecs="vorbis"',
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'wav': 'audio/wav; codecs="1"',
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'aac': 'audio/mp4; codecs="mp4a.40.2"'
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},
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audioEl = document.createElement('audio');
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Dancer.options = {};
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Dancer.setOptions = function (o) {
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for (var option in o) {
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if (o.hasOwnProperty(option)) {
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Dancer.options[option] = o[option];
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}
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}
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};
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})(window.Dancer);
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(function (undefined) {
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var Kick = function (dancer, o) {
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o = o || {};
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this.dancer = dancer;
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this.frequency = o.frequency !== undefined ? o.frequency : [0, 5];
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this.threshold = o.threshold !== undefined ? o.threshold : 0.3;
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this.decay = o.decay !== undefined ? o.decay : 0.02;
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this.onKick = o.onKick;
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this.offKick = o.offKick;
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this.isOn = false;
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this.currentThreshold = this.threshold;
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this.previousMag = 0;
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this.canUseRatio = true;
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this.canUseRatioHandle = null;
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var _this = this;
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this.dancer.bind('update', function () {
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_this.onUpdate();
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});
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};
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Kick.prototype = {
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on: function () {
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this.isOn = true;
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return this;
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},
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off: function () {
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this.isOn = false;
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return this;
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},
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set: function (o) {
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o = o || {};
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this.frequency = o.frequency !== undefined ? o.frequency : this.frequency;
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this.threshold = o.threshold !== undefined ? o.threshold : this.threshold;
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this.decay = o.decay !== undefined ? o.decay : this.decay;
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this.onKick = o.onKick || this.onKick;
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this.offKick = o.offKick || this.offKick;
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},
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onUpdate: function () {
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if (!this.isOn) { return; }
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var magnitude = this.maxAmplitude(this.frequency);
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if (magnitude >= this.currentThreshold && magnitude >= this.threshold) {
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this.currentThreshold = magnitude;
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this.onKick && this.onKick.call(this.dancer, magnitude);
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this.canUseRatio = false;
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if (this.canUseRatioHandle) {
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clearTimeout(this.canUseRatioHandle);
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this.canUseRatioHandle = null;
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}
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var self = this;
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this.canUseRatioHandle = setTimeout(function () {
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self.canUseRatio = true;
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}, 5000);
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} else {
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if (magnitude / this.previousMag > this.threshold * 5 && magnitude > 0.1 && this.canUseRatio) {
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this.onKick && this.onKick.call(this.dancer, magnitude, magnitude / this.previousMag);
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} else {
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this.offKick && this.offKick.call(this.dancer, magnitude);
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}
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this.currentThreshold -= this.decay;
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this.previousMag = (magnitude > 0) ? magnitude : 0.0001;
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}
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},
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maxAmplitude: function (frequency) {
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var max = 0, fft = this.dancer.getSpectrum();
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// Sloppy array check
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if (!frequency.length) {
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return frequency < fft.length ?
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fft[~~frequency] :
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null;
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}
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for (var i = frequency[0], l = frequency[1]; i <= l; i++) {
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if (fft[i] > max) { max = fft[i]; }
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}
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return max;
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}
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};
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window.Dancer.Kick = Kick;
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})();
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(function () {
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var
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SAMPLE_SIZE = 2048,
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SAMPLE_RATE = 44100;
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var adapter = function (dancer) {
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var context;
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if ('AudioContext' in window) {
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context = new AudioContext();
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} else {
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context = new webkitAudioContext();
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}
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this.dancer = dancer;
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this.context = context;
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};
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adapter.prototype = {
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load: function (_source, boost) {
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var _this = this;
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this.source = this.context.createMediaStreamSource(_source);
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this.isLoaded = false;
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this.progress = 0;
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if (this.proc) {
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this.proc.onaudioprocess = null;
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delete this.proc;
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}
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this.proc = this.context.createScriptProcessor(SAMPLE_SIZE / 2, 1, 1);
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this.proc.onaudioprocess = function (e) {
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_this.update.call(_this, e);
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};
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this.gain = this.context.createGain();
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this.fft = new FFT(SAMPLE_SIZE / 2, SAMPLE_RATE, boost);
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this.signal = new Float32Array(SAMPLE_SIZE / 2);
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connectContext.call(_this);
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return this.source;
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},
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getWaveform: function () {
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return this.signal;
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},
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getSpectrum: function () {
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return this.fft.spectrum;
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},
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update: function (e) {
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var
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buffers = [],
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channels = e.inputBuffer.numberOfChannels,
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resolution = SAMPLE_SIZE / channels,
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sum = function (prev, curr) {
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return prev[i] + curr[i];
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}, i;
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for (i = channels; i--;) {
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buffers.push(e.inputBuffer.getChannelData(i));
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}
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for (i = 0; i < resolution; i++) {
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this.signal[i] = channels > 1 ?
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buffers.reduce(sum) / channels :
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buffers[0][i];
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}
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this.fft.forward(this.signal);
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this.dancer.trigger('update');
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}
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};
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function connectContext() {
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this.source.connect(this.proc);
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this.source.connect(this.gain);
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this.gain.connect(this.context.destination);
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this.proc.connect(this.context.destination);
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this.isLoaded = true;
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this.progress = 1;
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this.dancer.trigger('loaded');
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}
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Dancer.adapters.webaudio = adapter;
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})();
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/*
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* DSP.js - a comprehensive digital signal processing library for javascript
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*
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* Created by Corban Brook <corbanbrook@gmail.com> on 2010-01-01.
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* Copyright 2010 Corban Brook. All rights reserved.
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*
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*/
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// Fourier Transform Module used by DFT, FFT, RFFT
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function FourierTransform(bufferSize, sampleRate, boost) {
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this.bufferSize = bufferSize;
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this.sampleRate = sampleRate;
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this.bandwidth = 2 / bufferSize * sampleRate / 2;
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this.boost = boost ? boost : 1;
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this.spectrum = new Float32Array(bufferSize / 2);
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this.real = new Float32Array(bufferSize);
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this.imag = new Float32Array(bufferSize);
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this.peakBand = 0;
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this.peak = 0;
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/**
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* Calculates the *middle* frequency of an FFT band.
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*
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* @param {Number} index The index of the FFT band.
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*
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* @returns The middle frequency in Hz.
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*/
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this.getBandFrequency = function (index) {
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return this.bandwidth * index + this.bandwidth / 2;
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};
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this.setBoost = function (boost) {
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this.boost = boost;
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};
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this.calculateSpectrum = function () {
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var spectrum = this.spectrum,
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real = this.real,
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imag = this.imag,
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boost = this.boost,
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bSi = 2 / this.bufferSize,
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sqrt = Math.sqrt,
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rval,
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ival,
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mag;
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for (var i = 0, N = bufferSize / 2; i < N; i++) {
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rval = real[i];
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ival = imag[i];
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mag = bSi * sqrt(rval * rval + ival * ival);
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if (mag > this.peak) {
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this.peakBand = i;
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this.peak = mag;
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}
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spectrum[i] = mag * boost;
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}
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};
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}
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/**
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* FFT is a class for calculating the Discrete Fourier Transform of a signal
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* with the Fast Fourier Transform algorithm.
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*
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* @param {Number} bufferSize The size of the sample buffer to be computed. Must be power of 2
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* @param {Number} sampleRate The sampleRate of the buffer (eg. 44100)
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* @param {Number} boost The coefficient
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*
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* @constructor
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*/
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function FFT(bufferSize, sampleRate, boost) {
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FourierTransform.call(this, bufferSize, sampleRate, boost);
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this.reverseTable = new Uint32Array(bufferSize);
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var limit = 1;
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var bit = bufferSize >> 1;
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var i;
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while (limit < bufferSize) {
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for (i = 0; i < limit; i++) {
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this.reverseTable[i + limit] = this.reverseTable[i] + bit;
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}
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limit = limit << 1;
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bit = bit >> 1;
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}
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this.sinTable = new Float32Array(bufferSize);
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this.cosTable = new Float32Array(bufferSize);
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for (i = 0; i < bufferSize; i++) {
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this.sinTable[i] = Math.sin(-Math.PI / i);
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this.cosTable[i] = Math.cos(-Math.PI / i);
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}
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}
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/**
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* Performs a forward transform on the sample buffer.
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* Converts a time domain signal to frequency domain spectra.
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*
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* @param {Array} buffer The sample buffer. Buffer Length must be power of 2
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*
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* @returns The frequency spectrum array
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*/
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FFT.prototype.forward = function (buffer) {
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// Locally scope variables for speed up
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var bufferSize = this.bufferSize,
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cosTable = this.cosTable,
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sinTable = this.sinTable,
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reverseTable = this.reverseTable,
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real = this.real,
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imag = this.imag,
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spectrum = this.spectrum;
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var k = Math.floor(Math.log(bufferSize) / Math.LN2);
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if (Math.pow(2, k) !== bufferSize) { throw "Invalid buffer size, must be a power of 2."; }
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if (bufferSize !== buffer.length) { throw "Supplied buffer is not the same size as defined FFT. FFT Size: " + bufferSize + " Buffer Size: " + buffer.length; }
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var halfSize = 1,
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phaseShiftStepReal,
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phaseShiftStepImag,
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currentPhaseShiftReal,
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currentPhaseShiftImag,
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off,
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tr,
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ti,
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tmpReal,
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i;
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for (i = 0; i < bufferSize; i++) {
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real[i] = buffer[reverseTable[i]];
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imag[i] = 0;
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}
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while (halfSize < bufferSize) {
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//phaseShiftStepReal = Math.cos(-Math.PI/halfSize);
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//phaseShiftStepImag = Math.sin(-Math.PI/halfSize);
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phaseShiftStepReal = cosTable[halfSize];
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phaseShiftStepImag = sinTable[halfSize];
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currentPhaseShiftReal = 1;
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currentPhaseShiftImag = 0;
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for (var fftStep = 0; fftStep < halfSize; fftStep++) {
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i = fftStep;
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while (i < bufferSize) {
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off = i + halfSize;
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tr = (currentPhaseShiftReal * real[off]) - (currentPhaseShiftImag * imag[off]);
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ti = (currentPhaseShiftReal * imag[off]) + (currentPhaseShiftImag * real[off]);
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real[off] = real[i] - tr;
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imag[off] = imag[i] - ti;
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real[i] += tr;
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imag[i] += ti;
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i += halfSize << 1;
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}
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tmpReal = currentPhaseShiftReal;
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currentPhaseShiftReal = (tmpReal * phaseShiftStepReal) - (currentPhaseShiftImag * phaseShiftStepImag);
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currentPhaseShiftImag = (tmpReal * phaseShiftStepImag) + (currentPhaseShiftImag * phaseShiftStepReal);
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}
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halfSize = halfSize << 1;
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}
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return this.calculateSpectrum();
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}; |