mirror of
https://github.com/Tonejs/Tone.js
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384 lines
No EOL
11 KiB
JavaScript
384 lines
No EOL
11 KiB
JavaScript
define(["Tone/core/Tone", "Tone/signal/WaveShaper", "Tone/core/Type"], function(Tone){
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"use strict";
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/**
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* @class A signal is an audio-rate value. Tone.Signal is a core component of the library.
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* Unlike a number, Signals can be scheduled with sample-level accuracy. Tone.Signal
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* has all of the methods available to native Web Audio
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* [AudioParam](http://webaudio.github.io/web-audio-api/#the-audioparam-interface)
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* as well as additional conveniences. Read more about working with signals
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* [here](https://github.com/Tonejs/Tone.js/wiki/Signals).
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*
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* @constructor
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* @extends {Tone.SignalBase}
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* @param {Number|AudioParam} [value] Initial value of the signal. If an AudioParam
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* is passed in, that parameter will be wrapped
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* and controlled by the Signal.
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* @param {string} [units=Number] unit The units the signal is in.
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* @example
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* var signal = new Tone.Signal(10);
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*/
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Tone.Signal = function(){
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var options = this.optionsObject(arguments, ["value", "units"], Tone.Signal.defaults);
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/**
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* The units of the signal.
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* @type {string}
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*/
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this.units = options.units;
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/**
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* When true, converts the set value
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* based on the units given. When false,
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* applies no conversion and the units
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* are merely used as a label.
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* @type {boolean}
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*/
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this.convert = options.convert;
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/**
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* True if the signal value is being overridden by
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* a connected signal.
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* @readOnly
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* @type {boolean}
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* @private
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*/
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this.overridden = false;
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/**
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* The node where the constant signal value is scaled.
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* @type {GainNode}
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* @private
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*/
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this.output = this._scaler = this.context.createGain();
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/**
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* the minimum output value
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* @type {number}
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* @private
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*/
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this._minOutput = 0.00001;
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/**
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* The node where the value is set.
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* @type {AudioParam}
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* @private
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*/
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this.input = this._value = this._scaler.gain;
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if (options.value instanceof AudioParam){
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this._scaler.connect(options.value);
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//zero out the value
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options.value.value = 0;
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} else {
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if (!this.isUndef(options.param)){
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this._scaler.connect(options.param);
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options.param.value = 0;
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}
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this.value = options.value;
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}
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//connect the constant 1 output to the node output
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Tone.Signal._constant.chain(this._scaler);
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};
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Tone.extend(Tone.Signal, Tone.SignalBase);
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/**
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* The default values
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* @type {Object}
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* @static
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* @const
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*/
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Tone.Signal.defaults = {
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"value" : 0,
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"param" : undefined,
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"units" : Tone.Type.Default,
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"convert" : true,
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};
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/**
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* The current value of the signal.
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* @memberOf Tone.Signal#
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* @type {Number}
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* @name value
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*/
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Object.defineProperty(Tone.Signal.prototype, "value", {
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get : function(){
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return this._toUnits(this._value.value);
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},
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set : function(value){
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var convertedVal = this._fromUnits(value);
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this._value.value = convertedVal;
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}
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});
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/**
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* Convert the given value from the type specified by Tone.Signal.units
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* into the destination value (such as gain).
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* @private
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* @param {*} val the value to convert
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* @return {number} the number which the value should be set to
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*/
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Tone.Signal.prototype._fromUnits = function(val){
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if (this.convert || this.isUndef(this.convert)){
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switch(this.units){
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case Tone.Type.Time:
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return this.toSeconds(val);
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case Tone.Type.Frequency:
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return this.toFrequency(val);
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case Tone.Type.Decibels:
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return this.dbToGain(val);
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case Tone.Type.NormalRange:
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return Math.min(Math.max(val, 0), 1);
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case Tone.Type.AudioRange:
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return Math.min(Math.max(val, -1), 1);
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case Tone.Type.Positive:
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return Math.max(val, 0);
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default:
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return val;
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}
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} else {
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return val;
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}
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};
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/**
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* Convert the signals true value into the units specified by Tone.Signal.units.
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* @private
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* @param {number} val the value to convert
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* @return {number}
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*/
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Tone.Signal.prototype._toUnits = function(val){
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if (this.convert || this.isUndef(this.convert)){
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switch(this.units){
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case Tone.Type.Decibels:
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return this.gainToDb(val);
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default:
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return val;
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}
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} else {
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return val;
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}
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};
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/**
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* Schedules a parameter value change at the given time.
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* @param {*} value The value to set the signal.
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* @param {Time} time The time when the change should occur.
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* @returns {Tone.Signal} this
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* @example
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* //set the frequency to "G4" in exactly 1 second from now.
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* freq.setValueAtTime("G4", "+1");
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*/
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Tone.Signal.prototype.setValueAtTime = function(value, time){
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value = this._fromUnits(value);
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this._value.setValueAtTime(value, this.toSeconds(time));
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return this;
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};
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/**
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* Creates a schedule point with the current value at the current time.
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* This is useful for creating an automation anchor point in order to
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* schedule changes from the current value.
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*
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* @param {number=} now (Optionally) pass the now value in.
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* @returns {Tone.Signal} this
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*/
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Tone.Signal.prototype.setRampPoint = function(now){
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now = this.defaultArg(now, this.now());
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var currentVal = this._value.value;
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this._value.setValueAtTime(currentVal, now);
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return this;
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};
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/**
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* Schedules a linear continuous change in parameter value from the
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* previous scheduled parameter value to the given value.
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*
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* @param {number} value
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* @param {Time} endTime
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* @returns {Tone.Signal} this
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*/
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Tone.Signal.prototype.linearRampToValueAtTime = function(value, endTime){
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value = this._fromUnits(value);
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this._value.linearRampToValueAtTime(value, this.toSeconds(endTime));
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return this;
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};
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/**
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* Schedules an exponential continuous change in parameter value from
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* the previous scheduled parameter value to the given value.
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*
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* @param {number} value
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* @param {Time} endTime
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* @returns {Tone.Signal} this
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*/
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Tone.Signal.prototype.exponentialRampToValueAtTime = function(value, endTime){
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value = this._fromUnits(value);
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value = Math.max(this._minOutput, value);
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this._value.exponentialRampToValueAtTime(value, this.toSeconds(endTime));
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return this;
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};
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/**
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* Schedules an exponential continuous change in parameter value from
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* the current time and current value to the given value over the
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* duration of the rampTime.
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*
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* @param {number} value The value to ramp to.
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* @param {Time} rampTime the time that it takes the
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* value to ramp from it's current value
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* @returns {Tone.Signal} this
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* @example
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* //exponentially ramp to the value 2 over 4 seconds.
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* signal.exponentialRampToValue(2, 4);
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*/
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Tone.Signal.prototype.exponentialRampToValue = function(value, rampTime){
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var now = this.now();
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// exponentialRampToValueAt cannot ever ramp from 0, apparently.
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// More info: https://bugzilla.mozilla.org/show_bug.cgi?id=1125600#c2
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var currentVal = this.value;
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this.setValueAtTime(Math.max(currentVal, this._minOutput), now);
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this.exponentialRampToValueAtTime(value, now + this.toSeconds(rampTime));
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return this;
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};
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/**
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* Schedules an linear continuous change in parameter value from
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* the current time and current value to the given value over the
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* duration of the rampTime.
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*
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* @param {number} value The value to ramp to.
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* @param {Time} rampTime the time that it takes the
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* value to ramp from it's current value
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* @returns {Tone.Signal} this
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* @example
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* //linearly ramp to the value 4 over 3 seconds.
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* signal.linearRampToValue(4, 3);
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*/
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Tone.Signal.prototype.linearRampToValue = function(value, rampTime){
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var now = this.now();
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this.setRampPoint(now);
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this.linearRampToValueAtTime(value, now + this.toSeconds(rampTime));
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return this;
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};
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/**
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* Start exponentially approaching the target value at the given time with
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* a rate having the given time constant.
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* @param {number} value
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* @param {Time} startTime
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* @param {number} timeConstant
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* @returns {Tone.Signal} this
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*/
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Tone.Signal.prototype.setTargetAtTime = function(value, startTime, timeConstant){
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value = this._fromUnits(value);
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// The value will never be able to approach without timeConstant > 0.
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// http://www.w3.org/TR/webaudio/#dfn-setTargetAtTime, where the equation
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// is described. 0 results in a division by 0.
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value = Math.max(this._minOutput, value);
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timeConstant = Math.max(this._minOutput, timeConstant);
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this._value.setTargetAtTime(value, this.toSeconds(startTime), timeConstant);
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return this;
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};
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/**
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* Sets an array of arbitrary parameter values starting at the given time
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* for the given duration.
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*
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* @param {Array} values
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* @param {Time} startTime
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* @param {Time} duration
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* @returns {Tone.Signal} this
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*/
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Tone.Signal.prototype.setValueCurveAtTime = function(values, startTime, duration){
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for (var i = 0; i < values.length; i++){
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values[i] = this._fromUnits(values[i]);
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}
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this._value.setValueCurveAtTime(values, this.toSeconds(startTime), this.toSeconds(duration));
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return this;
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};
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/**
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* Cancels all scheduled parameter changes with times greater than or
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* equal to startTime.
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*
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* @param {Time} startTime
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* @returns {Tone.Signal} this
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*/
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Tone.Signal.prototype.cancelScheduledValues = function(startTime){
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this._value.cancelScheduledValues(this.toSeconds(startTime));
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return this;
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};
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/**
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* Ramps to the given value over the duration of the rampTime.
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* Automatically selects the best ramp type (exponential or linear)
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* depending on the `units` of the signal
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*
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* @param {number} value
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* @param {Time} rampTime the time that it takes the
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* value to ramp from it's current value
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* @returns {Tone.Signal} this
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* @example
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* //ramp to the value either linearly or exponentially
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* //depending on the "units" value of the signal
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* signal.rampTo(0, 10);
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*/
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Tone.Signal.prototype.rampTo = function(value, rampTime){
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rampTime = this.defaultArg(rampTime, 0);
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if (this.units === Tone.Type.Frequency || this.units === Tone.Type.BPM){
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this.exponentialRampToValue(value, rampTime);
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} else {
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this.linearRampToValue(value, rampTime);
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}
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return this;
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};
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/**
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* dispose and disconnect
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* @returns {Tone.Signal} this
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*/
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Tone.Signal.prototype.dispose = function(){
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Tone.prototype.dispose.call(this);
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this._value = null;
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this._scaler = null;
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return this;
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};
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///////////////////////////////////////////////////////////////////////////
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// STATIC
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///////////////////////////////////////////////////////////////////////////
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/**
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* Generates a constant output of 1.
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* @static
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* @private
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* @const
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* @type {AudioBufferSourceNode}
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*/
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Tone.Signal._constant = null;
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/**
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* initializer function
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*/
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Tone._initAudioContext(function(audioContext){
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var buffer = audioContext.createBuffer(1, 128, audioContext.sampleRate);
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var arr = buffer.getChannelData(0);
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for (var i = 0; i < arr.length; i++){
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arr[i] = 1;
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}
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Tone.Signal._constant = audioContext.createBufferSource();
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Tone.Signal._constant.channelCount = 1;
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Tone.Signal._constant.channelCountMode = "explicit";
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Tone.Signal._constant.buffer = buffer;
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Tone.Signal._constant.loop = true;
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Tone.Signal._constant.start(0);
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Tone.Signal._constant.noGC();
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});
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return Tone.Signal;
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}); |