Tone.js/Tone/component/AmplitudeEnvelope.js

import Tone from "../core/Tone";
import "../component/Envelope";
import "../core/Gain";

/**
 *  @class  Tone.AmplitudeEnvelope is a Tone.Envelope connected to a gain node.
 *          Unlike Tone.Envelope, which outputs the envelope's value, Tone.AmplitudeEnvelope accepts
 *          an audio signal as the input and will apply the envelope to the amplitude
 *          of the signal. Read more about ADSR Envelopes on [Wikipedia](https://en.wikipedia.org/wiki/Synthesizer#ADSR_envelope).
 *
 *  @constructor
 *  @extends {Tone.Envelope}
 *  @param {Time|Object} [attack] The amount of time it takes for the envelope to go from
 *                               0 to it's maximum value.
 *  @param {Time} [decay]	The period of time after the attack that it takes for the envelope
 *                       	to fall to the sustain value.
 *  @param {NormalRange} [sustain]	The percent of the maximum value that the envelope rests at until
 *                                	the release is triggered.
 *  @param {Time} [release]	The amount of time after the release is triggered it takes to reach 0.
 *  @example
 * var ampEnv = new Tone.AmplitudeEnvelope({
 * 	"attack": 0.1,
 * 	"decay": 0.2,
 * 	"sustain": 1.0,
 * 	"release": 0.8
 * }).toMaster();
 * //create an oscillator and connect it
 * var osc = new Tone.Oscillator().connect(ampEnv).start();
 * //trigger the envelopes attack and release "8t" apart
 * ampEnv.triggerAttackRelease("8t");
 */
Tone.AmplitudeEnvelope = function(){

	Tone.Envelope.apply(this, arguments);

	/**
	 *  the input node
	 *  @type {GainNode}
	 *  @private
	 */
	this.input = this.output = new Tone.Gain();

	this._sig.connect(this.output.gain);
};

Tone.extend(Tone.AmplitudeEnvelope, Tone.Envelope);

/**
 *  Clean up
 *  @return  {Tone.AmplitudeEnvelope}  this
 */
Tone.AmplitudeEnvelope.prototype.dispose = function(){
	Tone.Envelope.prototype.dispose.call(this);
	return this;
};

export default Tone.AmplitudeEnvelope;