mirror of
https://github.com/Tonejs/Tone.js
synced 2024-11-16 16:48:00 +00:00
118 lines
2.8 KiB
JavaScript
118 lines
2.8 KiB
JavaScript
define(["Tone/core/Tone", "Tone/signal/Abs", "Tone/signal/Subtract",
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"Tone/signal/Signal", "Tone/type/Type", "Tone/core/Delay", "Tone/core/AudioNode"], function(Tone){
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"use strict";
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/**
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* @class Tone.Follower is a crude envelope follower which will follow
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* the amplitude of an incoming signal. Read more about envelope followers (also known
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* as envelope detectors) on [Wikipedia](https://en.wikipedia.org/wiki/Envelope_detector).
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*
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* @constructor
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* @extends {Tone.AudioNode}
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* @param {Time} [smoothing=0.05] The rate of change of the follower.
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* @example
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* var follower = new Tone.Follower(0.3);
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*/
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Tone.Follower = function(){
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var options = Tone.defaults(arguments, ["smoothing"], Tone.Follower);
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Tone.AudioNode.call(this);
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this.createInsOuts(1, 1);
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/**
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* @type {Tone.Abs}
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* @private
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*/
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this._abs = new Tone.Abs();
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/**
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* the lowpass filter which smooths the input
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* @type {BiquadFilterNode}
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* @private
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*/
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this._filter = this.context.createBiquadFilter();
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this._filter.type = "lowpass";
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this._filter.frequency.value = 0;
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this._filter.Q.value = 0;
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/**
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* @type {Tone.Subtract}
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* @private
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*/
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this._sub = new Tone.Subtract();
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/**
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* delay node to compare change over time
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* @type {Tone.Delay}
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* @private
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*/
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this._delay = new Tone.Delay(this.blockTime);
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/**
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* the smoothing value
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* @private
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* @type {Number}
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*/
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this._smoothing = options.smoothing;
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this.input.connect(this._delay, this._sub);
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this.input.connect(this._sub, 0, 1);
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this._sub.chain(this._abs, this._filter, this.output);
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//set the smoothing initially
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this.smoothing = options.smoothing;
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};
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Tone.extend(Tone.Follower, Tone.AudioNode);
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/**
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* @static
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* @type {Object}
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*/
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Tone.Follower.defaults = {
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"smoothing" : 0.05,
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};
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/**
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* The attack time.
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* @memberOf Tone.Follower#
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* @type {Time}
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* @name smoothing
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*/
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Object.defineProperty(Tone.Follower.prototype, "smoothing", {
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get : function(){
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return this._smoothing;
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},
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set : function(smoothing){
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this._smoothing = smoothing;
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this._filter.frequency.value = Tone.Time(smoothing).toFrequency() * 0.5;
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}
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});
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/**
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* Borrows the connect method from Signal so that the output can be used
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* as a Tone.Signal control signal.
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* @function
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*/
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Tone.Follower.prototype.connect = Tone.SignalBase.prototype.connect;
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/**
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* dispose
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* @returns {Tone.Follower} this
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*/
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Tone.Follower.prototype.dispose = function(){
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Tone.AudioNode.prototype.dispose.call(this);
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this._filter.disconnect();
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this._filter = null;
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this._delay.dispose();
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this._delay = null;
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this._sub.disconnect();
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this._sub = null;
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this._abs.dispose();
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this._abs = null;
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return this;
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};
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return Tone.Follower;
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});
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