mirror of
https://github.com/Tonejs/Tone.js
synced 2024-11-16 16:48:00 +00:00
276 lines
No EOL
7.4 KiB
JavaScript
276 lines
No EOL
7.4 KiB
JavaScript
define(["Tone/core/Tone", "Tone/core/Transport"], function(Tone){
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"use strict";
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/**
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* @class A timed note. Creating a note will register a callback
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* which will be invoked on the channel at the time with
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* whatever value was specified.
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*
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* @constructor
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* @param {number|string} channel the channel name of the note
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* @param {Tone.Time} time the time when the note will occur
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* @param {string|number|Object|Array} value the value of the note
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*/
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Tone.Note = function(channel, time, value){
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/**
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* the value of the note. This value is returned
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* when the channel callback is invoked.
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*
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* @type {string|number|Object}
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*/
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this.value = value;
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/**
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* the channel name or number
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*
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* @type {string|number}
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* @private
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*/
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this._channel = channel;
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/**
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* an internal reference to the id of the timeline
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* callback which is set.
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*
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* @type {number}
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* @private
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*/
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this._timelineID = Tone.Transport.setTimeline(this._trigger.bind(this), time);
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};
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/**
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* invoked by the timeline
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* @private
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* @param {number} time the time at which the note should play
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*/
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Tone.Note.prototype._trigger = function(time){
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//invoke the callback
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channelCallbacks(this._channel, time, this.value);
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};
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/**
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* clean up
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*/
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Tone.Note.prototype.dispose = function(){
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Tone.Tranport.clearTimeline(this._timelineID);
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this.value = null;
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};
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/**
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* @private
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* @static
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* @type {Object}
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*/
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var NoteChannels = {};
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/**
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* invoke all of the callbacks on a specific channel
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* @private
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*/
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function channelCallbacks(channel, time, value){
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if (NoteChannels.hasOwnProperty(channel)){
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var callbacks = NoteChannels[channel];
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for (var i = 0, len = callbacks.length; i < len; i++){
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var callback = callbacks[i];
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if (Array.isArray(value)){
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callback.apply(window, [time].concat(value));
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} else {
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callback(time, value);
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}
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}
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}
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}
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/**
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* listen to a specific channel, get all of the note callbacks
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* @static
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* @param {string|number} channel the channel to route note events from
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* @param {function(*)} callback callback to be invoked when a note will occur
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* on the specified channel
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*/
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Tone.Note.route = function(channel, callback){
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if (NoteChannels.hasOwnProperty(channel)){
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NoteChannels[channel].push(callback);
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} else {
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NoteChannels[channel] = [callback];
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}
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};
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/**
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* remove a callback from a channel
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* @static
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*/
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Tone.Note.unroute = function(channel, callback){
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if (NoteChannels.hasOwnProperty(channel)){
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var channelCallback = NoteChannels[channel];
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var index = channelCallback.indexOf(callback);
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if (index !== -1){
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NoteChannels[channel].splice(index, 1);
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}
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}
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};
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/**
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* Parses a score and registers all of the notes along the timeline.
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*
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* Scores are a JSON object with instruments at the top level
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* and an array of time and values. The value of a note can be 0 or more
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* parameters.
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*
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* The only requirement for the score format is that the time is the first (or only)
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* value in the array. All other values are optional and will be passed into the callback
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* function registered using ""
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*
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* ```javascript
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* var score = {
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* "synth" : [["0", "C3"], ["0:1", "D3"], ["0:2", "E3"], ... ],
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* "bass" : [["0", "C2"], ["1:0", "A2"], ["2:0", "C2"], ["3:0", "A2"], ... ],
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* "kick" : ["0", "0:2", "1:0", "1:2", "2:0", ... ],
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* //...
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* };
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* ```
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*
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* To convert MIDI files to score notation, take a look at utils/MidiToScore.js
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*
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* @static
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* @param {Object} score
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* @return {Array<Tone.Note>} an array of all of the notes that were created
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*/
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Tone.Note.parseScore = function(score){
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var notes = [];
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for (var inst in score){
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var part = score[inst];
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if (inst === "tempo"){
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Tone.Transport.setBpm(part);
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} else if (inst === "timeSignature"){
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Tone.Transport.setTimeSignature(part[0], part[1]);
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} else if (Array.isArray(part)){
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for (var i = 0; i < part.length; i++){
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var noteDescription = part[i];
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var note;
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if (Array.isArray(noteDescription)){
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var time = noteDescription[0];
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var value = noteDescription.slice(1);
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note = new Tone.Note(inst, time, value);
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} else {
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note = new Tone.Note(inst, noteDescription);
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}
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notes.push(note);
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}
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} else {
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throw new TypeError("score parts must be Arrays");
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}
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}
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return notes;
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};
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///////////////////////////////////////////////////////////////////////////
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// MUSIC NOTES
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//
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// Augments Tone.prototype to include note methods
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///////////////////////////////////////////////////////////////////////////
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var noteToIndex = { "c" : 0, "c#" : 1, "db" : 1, "d" : 2, "d#" : 3, "eb" : 3,
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"e" : 4, "f" : 5, "f#" : 6, "gb" : 6, "g" : 7, "g#" : 8, "ab" : 8,
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"a" : 9, "a#" : 10, "bb" : 10, "b" : 11
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};
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var noteIndexToNote = ["C", "C#", "D", "D#", "E", "F", "F#", "G", "G#", "A", "A#", "B"];
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var middleC = 261.6255653005986;
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/**
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* convert a note name to frequency (i.e. A4 to 440)
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* defined in "Tone/core/Note"
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*
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* @param {string} note
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* @return {number}
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*/
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Tone.prototype.noteToFrequency = function(note){
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//break apart the note by frequency and octave
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var parts = note.split(/(\d+)/);
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if (parts.length === 3){
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var index = noteToIndex[parts[0].toLowerCase()];
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var octave = parts[1];
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var noteNumber = index + parseInt(octave, 10) * 12;
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return Math.pow(2, (noteNumber - 48) / 12) * middleC;
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} else {
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return 0;
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}
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};
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/**
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* convert a note name (i.e. A4, C#5, etc to a frequency)
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* defined in "Tone/core/Note"
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*
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* @param {number} freq
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* @return {string}
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*/
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Tone.prototype.frequencyToNote = function(freq){
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var log = Math.log(freq / middleC) / Math.LN2;
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var noteNumber = Math.round(12 * log) + 48;
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var octave = Math.floor(noteNumber/12);
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var noteName = noteIndexToNote[noteNumber % 12];
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return noteName + octave.toString();
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};
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/**
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* convert an interval (in semitones) to a frequency ratio
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* defined in "Tone/core/Note"
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*
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* ```javascript
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* tone.intervalToFrequencyRatio(0); // returns 1
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* tone.intervalToFrequencyRatio(12); // returns 2
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* ```
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*
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* @param {number} interval the number of semitones above the base note
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* @return {number} the frequency ratio
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*/
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Tone.prototype.intervalToFrequencyRatio = function(interval){
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return Math.pow(2,(interval/12));
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};
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/**
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* convert a midi note number into a note name
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* defined in "Tone/core/Note"
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*
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* ```javascript
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* tone.midiToNote(60); // returns "C3"
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* ```
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*
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* @param {number} midiNumber the midi note number
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* @return {string} the note's name and octave
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*/
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Tone.prototype.midiToNote = function(midiNumber){
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var octave = Math.floor(midiNumber / 12) - 2;
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var note = midiNumber % 12;
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return noteIndexToNote[note] + octave;
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};
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/**
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* convert a note to it's midi value
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* defined in "Tone/core/Note"
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*
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* ```javascript
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* tone.noteToMidi("C3"); // returns 60
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* ```
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*
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* @param {string} note the note name (i.e. "C3")
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* @return {number} the midi value of that note
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*/
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Tone.prototype.noteToMidi = function(note){
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//break apart the note by frequency and octave
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var parts = note.split(/(\d+)/);
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if (parts.length === 3){
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var index = noteToIndex[parts[0].toLowerCase()];
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var octave = parts[1];
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return index + (parseInt(octave, 10) + 2) * 12;
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} else {
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return 0;
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}
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};
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return Tone.Note;
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}); |