//JS modules
var _ = require('lodash');
/**
* @author David B - laopunk
* @class notePlayer
* @classdesc A musical note that can be played in a browser. Plays for however long it has been defined to.
* @param {Object} obj - properties needed to instanciate the class
* @param {Object} obj.keynb - corresponding number on a piano keyboard
* @param {Object} obj.freq - sound frequency, in Hertz
* @param {Object} obj.octave - musical octave the note belongs to [1-8]
* @param {Object} obj.name - Full name of the note
* @property {number} pianoKeyNb - corresponding number on a piano keyboard
* @property {number} frequency - sound frequency, in Hertz
* @property {number} octave - musical octave the note belongs to [1-8]
* @property {string} name - Full name of the note
* @property {number} duration - length of time the sound has to be played, in seconds
* @property {number} volume - volume [0-1]
* @property {Boolean} verbose - verbose mode (true/false)
* @property {number} attack - time to ramp up to the desired volume [0-1]
* @property {number} release - time to ramp up from the desired volume to silence [0-1]
* @property {Object} audioContext - WebAudio audioContext
* @property {Object} destinationNode - WebAudio destinationNode
*/
function notePlayer(obj){
try{
//properties
this.pianoKeyNb = obj.keynb
this.frequency = obj.freq
this.octave = obj.name.substr(-1,1)
this.name = obj.name
this.duration = _.random(0.5,3,true)
this.volume = 1
this.verbose = false
this.attack = 0.3
this.release = 0.1
//audio API
this.audioContext = (obj.audioContext === void 0) ? new (window.AudioContext || window.webkitAudioContext)() : obj.audioContext;
this.destinationNode = this.audioContext.destination
}catch(err){
console.error(err)
return null
}
}
/**
* @function buildFromName
* @description builds a notePlayer from a specific musical note name
* @example buildFromName("C4")
* @param {string} noteName - Concatenation of note + octave [1-8]
* @param {Object} [audioContext] - The audioContext to render the sound. Created if not provided
*/
notePlayer.buildFromName = function(noteName,audioContext){
try{
//verify input
if (noteName === void 0) {throw "note name was not provided"};
//verify octave
OCTAVE_INPUT = parseInt(noteName.slice(-1))
if (OCTAVE_INPUT < 1 || OCTAVE_INPUT > 8) {throw "Invalid octave: "+noteName};
//replace flats with sharp if need be
NOTE_INPUT = noteName.slice(0,2)
DICT_TRANSLATIONS = {
"Cb": "B",
"Db": "C#",
"Eb": "D#",
"Fb": "E",
"Gb": "F#",
"Ab": "G#",
"Bb": "A#"
}
noteName = (DICT_TRANSLATIONS[NOTE_INPUT]) ? DICT_TRANSLATIONS[NOTE_INPUT]+OCTAVE_INPUT : noteName;
n = _(this.getNotesInfo()).find(function(e){
return e.name == noteName
})
if ( !n) { throw "Invalid note name: "+noteName+", did you forget to mention the octave nb ?"}
else{
n.audioContext = audioContext
return new notePlayer(n)
}
}catch(e){
console.error("NOTEPLAYER ERROR: "+e)
console.warn("USAGE: notePlayer.buildFromName(noteNameWithOctave,[audioContext]). i.e: buildFromName('G4')")
return null
}
}
/**
* @function buildFromFrequency
* @description builds a notePlayer from a specific frequence
* @example buildFromFrequency(440)
* @param {number} noteFreq - sound frequency, in Hertz
* @param {Object} [audioContext] - The audioContext to render the sound. Created if not provided
*/
notePlayer.buildFromFrequency = function(noteFreq,audioContext){
try{
//verify input
if (noteFreq === void 0) {throw "note frequency was not provided"};
list = this.getNotesInfo()
//eliminate junk
if (noteFreq < list[0].freq || noteFreq > list[list.length-1].freq) {
throw "Invalid frequency (out of range 27.5-4186): "+noteFreq
return null
}
//find closest frequency
closest = list.reduce(function (prev, curr) {
return (Math.abs(curr.freq - noteFreq) < Math.abs(prev.freq - noteFreq) ? curr : prev);
});
return this.buildFromName(closest.name,audioContext)
}catch(e){
console.error("NOTEPLAYER ERROR: "+e)
console.warn("USAGE: notePlayer.buildFromFrequency(frequency,[audioContext]). i.e: buildFromFrequency(440)")
return null
}
}
/**
* @function buildFromKeyNb
* @description builds a notePlayer from a specific piano key number
* @example buildFromKeyNb(49)
* @param {number} noteKeyNb - corresponding number on a piano keyboard
* @param {Object} [audioContext] - The audioContext to render the sound. Created if not provided
*/
notePlayer.buildFromKeyNb = function(noteKeyNb,audioContext){
try{
//verify input
if (noteKeyNb === void 0) {throw "note keyNumber was not provided"};
n = _(this.getNotesInfo()).find(function(e){
return e.keynb == noteKeyNb
})
if ( !n) { throw "Invalid keyNumber: "+noteKeyNb+", has to be within range 1-88"}
n.audioContext = audioContext
return new notePlayer(n)
}catch(e){
console.error("NOTEPLAYER ERROR: "+e)
console.warn("USAGE: notePlayer.buildFromKeyNb(noteKeyNb,[audioContext]). i.e: buildFromKeyNb(49)")
return null
}
}
/**
* @function buildFromKeyNb
* @description builds a notePlayer from a specific piano key number
* @example buildFromKeyNb(49)
* @param {number} noteKeyNb - corresponding number on a piano keyboard
* @param {Object} [audioContext] - The audioContext to render the sound. Created if not provided
*/
notePlayer.getNotesInfo = function(){
DICT_KEYS = ["A","A#","B","C","C#","D","D#","E","F","F#","G","G#"]
DICT_OCTAVES =[0,1,2,3,4,5,6,7,8]
FREQ = 25.95654359874657 //starting point for G#-1
KEYNB = 0 //sarting point for A0
return _(DICT_OCTAVES).map(function(v,k){
return _(DICT_KEYS).map(function(v2,k2){
KEYNB++
FREQ = FREQ * Math.pow(2, 1/12)
return {
"keynb": KEYNB
, "freq": FREQ
, "name": v2+v
}
})
.value()
})
.flatten()
.dropRightWhile(function(e,i){
return i >= 88
})
.value()
}
/**
* @function play
* @description plays the note
* @example play(function(){console.log("end play")})
* @param {Function} [callback] - callback function
* @returns {Object} Oscillator
*/
notePlayer.prototype.play = function(callback) {
if (this.verbose){
console.log("Note "+this.name+" will play for a duration of "+this.duration)
}
//creating oscillator & gain
var oscillator = this.audioContext.createOscillator()
oscillator.frequency.value = this.frequency
var gainNode = this.audioContext.createGain()
gainNode.gain.linearRampToValueAtTime(this.volume, this.audioContext.currentTime + this.attack);
gainNode.gain.setTargetAtTime(0, this.audioContext.currentTime + this.attack, this.release || this.attack);
//Connections
oscillator.connect(gainNode)
gainNode.connect(this.destinationNode)
//launch play
oscillator.start(0)
//event listeners
t_np = this
setTimeout(function(){
if(t_np.verbose){console.log("Note "+t_np.name+" has finished playing")}
oscillator.stop(0)
}, this.duration * 1000); //leaving time for the fadeout
oscillator.onended = function() {
if( callback ) { callback() }
}
return oscillator;
};
/**
* @function setAudioContext
* @description assigns a specific audiocontext to the note
* @example setAudioContext(ac)
* @param {Object} ac - Web Audio audioContext
*/
notePlayer.prototype.setAudioContext = function(ac) {
this.audioContext = (ac == void 0) ? this.audioContext : ac;
};
/**
* @function setDestinationNode
* @description assigns a specific destination node to the note (any connectable audioNode)
* @example setDestinationNode(audioContext.destination)
* @param {Object} dn - Web Audio destinationNode
*/
notePlayer.prototype.setDestinationNode = function(dn) {
this.destinationNode = (dn === void 0) ? this.audiocontext.destination : dn;
};
/**
* @function setDuration
* @description changes the time the note has to be played for
* @example setDuration(2.3)
* @param {Number} d - Time to play the note for, in second
*/
notePlayer.prototype.setDuration = function(d) {
this.duration = (d === void 0) ? this.duration : d;
};
/**
* @function setVolume
* @description changes the volume
* @example setVolume(0.5)
* @param {Number} v - Volume level
*/
notePlayer.prototype.setVolume = function(v) {
this.volume = (v === void 0) ? this.volume : v;
};
/**
* @function setVerbose
* @description switches verbose mode on/ff
* @example setVerbose(); setVerbose(false)
* @param {Number} [v] - True or false, default is true
*/
notePlayer.prototype.setVerbose = function(v) {
this.verbose = (v === void 0 || v === true) ? true : false;
};
/**
* @function setAttack
* @description Updates value of the note's attack
* @example setAttack(0.3)
* @param {Number} n - [0-1] the closer to 0 the longer the attack
*/
notePlayer.prototype.setAttack = function(n) {
this.attack = (n === void 0 || n % 1 === 0 ) ? this.attack : n;
};
/**
* @function setRelease
* @description Updates value of the note's release
* @example setRelease(0.3)
* @param {Number} n - [0-1] the closer to 0 the longer the release
*/
notePlayer.prototype.setRelease = function(n) {
this.release = (n === void 0 || n % 1 === 0 ) ? this.release : n;
};
module.exports = notePlayer