Tone.js/Tone/component/CrossFade.js
2015-07-04 15:25:37 -04:00

106 lines
2.7 KiB
JavaScript

define(["Tone/core/Tone", "Tone/signal/Signal", "Tone/signal/Expr", "Tone/signal/EqualPowerGain"], function(Tone){
"use strict";
/**
* @class Tone.Crossfade provides equal power fading between two inputs.
* More on crossfading technique [here](https://en.wikipedia.org/wiki/Fade_(audio_engineering)#Crossfading).
*
* @constructor
* @extends {Tone}
* @param {NormalRange} [initialFade=0.5]
* @example
* var crossFade = new Tone.CrossFade(0.5);
* //connect effect A to crossfade from
* //effect output 0 to crossfade input 0
* effectA.connect(crossFade, 0, 0);
* //connect effect B to crossfade from
* //effect output 0 to crossfade input 1
* effectB.connect(crossFade, 0, 1);
* crossFade.fade.value = 0;
* // ^ only effectA is output
* crossFade.fade.value = 1;
* // ^ only effectB is output
* crossFade.fade.value = 0.5;
* // ^ the two signals are mixed equally.
*/
Tone.CrossFade = function(initialFade){
Tone.call(this, 2, 1);
/**
* Alias for <code>input[0]</code>.
* @type {GainNode}
*/
this.a = this.input[0] = this.context.createGain();
/**
* Alias for <code>input[1]</code>.
* @type {GainNode}
*/
this.b = this.input[1] = this.context.createGain();
/**
* The mix between the two inputs. A fade value of 0
* will output 100% <code>input[0]</code> and
* a value of 1 will output 100% <code>input[1]</code>.
* @type {NormalRange}
* @signal
*/
this.fade = new Tone.Signal(this.defaultArg(initialFade, 0.5), Tone.Type.NormalRange);
/**
* equal power gain cross fade
* @private
* @type {Tone.EqualPowerGain}
*/
this._equalPowerA = new Tone.EqualPowerGain();
/**
* equal power gain cross fade
* @private
* @type {Tone.EqualPowerGain}
*/
this._equalPowerB = new Tone.EqualPowerGain();
/**
* invert the incoming signal
* @private
* @type {Tone}
*/
this._invert = new Tone.Expr("1 - $0");
//connections
this.a.connect(this.output);
this.b.connect(this.output);
this.fade.chain(this._equalPowerB, this.b.gain);
this.fade.chain(this._invert, this._equalPowerA, this.a.gain);
this._readOnly("fade");
};
Tone.extend(Tone.CrossFade);
/**
* clean up
* @returns {Tone.CrossFade} this
*/
Tone.CrossFade.prototype.dispose = function(){
Tone.prototype.dispose.call(this);
this._writable("fade");
this._equalPowerA.dispose();
this._equalPowerA = null;
this._equalPowerB.dispose();
this._equalPowerB = null;
this.fade.dispose();
this.fade = null;
this._invert.dispose();
this._invert = null;
this.a.disconnect();
this.a = null;
this.b.disconnect();
this.b = null;
return this;
};
return Tone.CrossFade;
});