/**
* A module for creating differnt kinds of noise ( defined as any nonconventional and/or mathematically calculated sound buffer )
* @module BB.AudioNoise
* @extends BB.AudioBase
*/
define(['./BB', './BB.AudioBase' ],
function( BB, AudioBase ){
'use strict';
/**
* A module for creating differnt kinds of noise ( defined as any nonconventional and/or mathematically calculated sound buffer )
* @class BB.AudioNoise
* @constructor
* @extends BB.AudioBase
*
* @param {Object} config this can either be a string (type of noise "white","pink","brown","perlin" ), or a custom function ( see example further down ) or a config object to initialize the Noise
* can contain the following:<br><br>
* <code class="code prettyprint">
* {<br>
* context: BB.Audio.context[2], // choose specific context <br>
* connect: fft, // overide default destination <br>
* volume: 0.5, // technically master "gain" (expolential multiplier)<br>
* duraton: 2, // in seconds (corresponds to length of buffer)<br>
* channels: 1, // channels in buffer <br>
* type: "pink", // "white","pink","brown","perlin" or custom function<br>
* }
* </code>
* <br>
* <br>
* @example
* in the example below instantiating the BB.AudioNoise creates a <a href="https://developer.mozilla.org/en-US/docs/Web/API/GainNode" target="_blank">GainNode</a> ( essentially the Noise's output ) connected to the default BB.Audio.context ( ie. AudioDestination )
* <br> <img src="../assets/images/audiosampler1.png"/>
* <br> everytime noise is played, for example: <code> white.makeNoise()</code>, a corresponding <a href="https://developer.mozilla.org/en-US/docs/Web/API/AudioBufferSourceNode" target="_blank">SourceNode</a> with the appropriate sound buffer (the initialized noise data) is created and connected to the Noise's master GainNode
* <br>
* <code class="code prettyprint">
* BB.Audio.init();<br>
* <br>
* var white = new BB.AudioNoise('white');<br>
* <br>
* white.makeNoise();// plays noise <br>
* var now = BB.Audio.context.currentTime; <br>
* white.makeNoise( 8, 0.5, now+3 ); // plays noise for 8 seconds, at half volume, 3 seconds from now <br><br>
*
* // example with config object<br>
* var brown = new BB.AudioNoise({<br>
* volume: 0.75,<br>
* type: "brown"<br>
* });<br><br>
*
* // example with custom function type<br>
* var noisey = new BB.AudioNoise(function(){<br>
* var frameCount = this.ctx.sampleRate \* this.duration;<br>
* for (var ch = 0; ch < this.channels; ch++) {<br>
* var data = this.buffer.getChannelData( ch );<br>
* for (var i = 0; i < frameCount; i++) {<br>
* data[i] = Math.random() * 2 - 1;<br>
* };<br>
* };<br>
* });<br>
* </code>
*
* view basic <a href="../../examples/editor/?file=audio-noise" target="_blank">BB.AudioNoise</a> example
*/
BB.AudioNoise = function( config ) {
BB.AudioBase.call(this, config);
var types = ["white","pink","brown","perlin"];
if(typeof config === "undefined"){ config = {}; }
else if(typeof config === "function" || typeof config === "string" && types.indexOf( config) >= 0 ){
var t = config;
config = { type:t };
} else if(typeof config === "string" && types.indexOf( config) < 0 ){
throw new Error('BB.AudioNoise: type should be either "white","pink","brown","perlin" or be a custom function');
}
this._type = (typeof config.type !== "undefined") ? config.type : "white";
if(typeof this._type==="string" && types.indexOf( this._type ) < 0 )
throw new Error('BB.AudioNoise: type should be either "white","pink","brown","perlin" or be a custom function');
else if( typeof this._type !== "string" && typeof this._type !== "function" )
throw new Error('BB.AudioNoise: type should be either "white","pink","brown","perlin" or be a custom function');
else if( typeof this._type === "function" ){
this._typecallback = config.type;
this._type = "custom";
}
/**
* buffer length in seconds
* @property duration
* @type Number
* @default 1
*/
this.duration = (typeof config.duration !== "undefined") ? config.duration : 1; // seconds
/**
* number of channels
* @property channels
* @type Number
* @default 2
*/
this.channels = (typeof config.channels !== "undefined") ? config.channels : 2; // stereo
/**
* the source node
* @property node
* @type AudioNode
*/
this.node = null;
/**
* the buffer object
* @property buffer
* @type AudioBuffer
*/
this.buffer = null;
this.isPlaying = false;
this._isOn = false;
this._durTimeout = null; // time out for makeNoise
this._initBuffer();
};
BB.AudioNoise.prototype = Object.create(BB.AudioBase.prototype);
BB.AudioNoise.prototype.constructor = BB.AudioNoise;
/**
* "white","pink","brown" or "custom"
* @property type
* @type String
* @default "white"
*/
Object.defineProperty(BB.AudioNoise.prototype, "type", {
get: function() {
return this._type;
},
set: function(v) {
var types = ["white","pink","brown","perlin"];
if(typeof v==="string" && types.indexOf( v ) < 0 )
throw new Error('BB.AudioNoise: type should be either "white","pink","brown","perlin" or be a custom function');
else if( typeof v !== "string" && typeof v !== "function" )
throw new Error('BB.AudioNoise: type should be either "white","pink","brown","perlin" or be a custom function');
if( typeof v === "string" ){
this._type = v;
if(this._isOn===true){
this.noiseOff();
this._initBuffer();
this.noiseOn();
} else {
this._initBuffer();
}
}
else if( typeof v === "function" ){
this._type = "custom";
this._typecallback = v;
if(this._isOn===true){
this.noiseOff();
this._initBuffer();
this.noiseOn();
} else {
this._initBuffer();
}
} else {
throw new Error('BB.AudioNoise: type should be either "white","pink","brown","perlin" or be a custom function');
}
}
});
// ---------------
BB.AudioNoise.prototype._initBuffer = function(){
var frameCount = this.ctx.sampleRate * this.duration;
this.buffer = this.ctx.createBuffer( this.channels, frameCount, this.ctx.sampleRate );
// noise maths via: http://noisehack.com/generate-noise-web-audio-api/
var ch, data, i, white;
if( this._type == "white" ){
// generate white noise buffer
for (ch = 0; ch < this.channels; ch++) {
data = this.buffer.getChannelData( ch );
for (i = 0; i < frameCount; i++) {
data[i] = Math.random() * 2 - 1;
}
}
}
else if ( this._type == "pink" ){
// generate pink noise buffer
for (ch = 0; ch < this.channels; ch++) {
var b0, b1, b2, b3, b4, b5, b6;
b0 = b1 = b2 = b3 = b4 = b5 = b6 = 0.0;
data = this.buffer.getChannelData( ch );
for (i = 0; i < frameCount; i++) {
white = Math.random() * 2 - 1;
b0 = 0.99886 * b0 + white * 0.0555179;
b1 = 0.99332 * b1 + white * 0.0750759;
b2 = 0.96900 * b2 + white * 0.1538520;
b3 = 0.86650 * b3 + white * 0.3104856;
b4 = 0.55000 * b4 + white * 0.5329522;
b5 = -0.7616 * b5 - white * 0.0168980;
data[i] = b0 + b1 + b2 + b3 + b4 + b5 + b6 + white * 0.5362;
data[i] *= 0.11; // (roughly) compensate for gain
b6 = white * 0.115926;
}
}
}
else if ( this._type == "brown" ){
// generate pink brownian ( aka. brown or red ) buffer
for (ch = 0; ch < this.channels; ch++) {
data = this.buffer.getChannelData( ch );
var lastOut = 0.0;
for (i = 0; i < frameCount; i++) {
white = Math.random() * 2 - 1;
data[i] = (lastOut + (0.02 * white)) / 1.02;
lastOut = data[i];
data[i] *= 3.5; // (roughly) compensate for gain
}
}
}
else if ( this._type == "perlin" ){
// generate perlin noise buffer...
// ... right now just sounds like short white noise buffer on loop
// ... need to make this more interesting?
for (ch = 0; ch < this.channels; ch++) {
data = this.buffer.getChannelData( ch );
for (i = 0; i < frameCount; i++) {
data[i] = BB.MathUtils.noise(i) * 2 - 1;
}
}
}
else if( this._type == "custom" ){
this._typecallback();
// ---- FOR EXMPLE ----
// function(){
// var frameCount = this.ctx.sampleRate * this.duration;
// for (var ch = 0; ch < this.channels; ch++) {
// var data = this.buffer.getChannelData( ch );
// for (var i = 0; i < frameCount; i++) {
// data[i] = Math.random() * 2 - 1;
// };
// };
// }
}
};
// ---------------
/**
* plays noise for a specified period of time
* @method makeNoise
* @param {Number} [duration] how long to play the noise (in seconds)
* @param {Number} [velocity] how loud (scalar value applied to master volume)
* @param {Number} [schedule] when to play it
*
* @example
* <code class="code prettyprint">
* BB.Audio.init();<br>
* <br>
* var whitenoise = new BB.AudioNoise({<br>
* type: "white",<br>
* volume: 0.75<br>
* });<br>
* <br>
* // plays for a quarter second, at twice the initial 0.75 volume ( ie. 1.5 ) <br>
* whitenoise.makeNoise( 0.25, 2 ); <br><br>
* // plays for 1 second at the original volume (0.75), will start playing 5 seconds from now<br>
* var now = BB.Audio.context.currentTime; <br>
* whitenoise.makeNoise( 1, 1, now+5 );
* </code>
*/
BB.AudioNoise.prototype.makeNoise = function( duration, velocity, schedule ){
var dur = (typeof duration!=="undefined") ? duration : this.duration;
var initvol;
if(typeof velocity !== "undefined") {
initvol = this.volume;
this.volume = velocity;
}
this.noiseOn( schedule, true );
if( this._durTimeout !== "undefined" ) clearTimeout( this._durTimeout );
var self = this;
this._durTimeout = setTimeout(function(){
self.noiseOff( true );
if(typeof velocity !== "undefined") self.volume = initvol;
}, dur*1000 );
};
/**
* starts playing the noise
* @method noiseOn
* @param {Number} [schedule] when to play
*
* @example
* <code class="code prettyprint">
* BB.Audio.init();<br>
* <br>
* var whitenoise = new BB.AudioNoise(); // default white noise<br>
* <br>
* whitenoise.noiseOn();
* </code>
*/
BB.AudioNoise.prototype.noiseOn = function( schedule, fromMakeNoise ){
if( this.isPlaying === true ) throw new Error('BB.AudioNoise.noiseOn: is already on');
if(typeof schedule === "undefined") schedule = 0;
this.node = this.ctx.createBufferSource();
this.node.buffer = this.buffer;
this.node.loop = true;
this.node.connect( this.gain );
this.node.start(schedule);
if(typeof fromMakeNoise==="undefined" || fromMakeNoise===false) this._isOn = true;
this.isPlaying = true;
};
/**
* stops playing the noise
* @method noiseOff
*
* @example
* <code class="code prettyprint">
* BB.Audio.init();<br>
* <br>
* var whitenoise = new BB.AudioNoise(); // default white noise<br>
* <br>
* whitenoise.noiseOn();<br>
* whitenoise.noiseOff();
* </code>
*/
BB.AudioNoise.prototype.noiseOff = function( fromMakeNoise ){
if( this.isPlaying === false ) throw new Error('BB.AudioNoise.noiseOn: is already off');
this.node.stop();
this.isPlaying = false;
if(typeof fromMakeNoise==="undefined" || fromMakeNoise===false) this._isOn = false;
};
return BB.AudioNoise;
});
