Tone.js/Tone/signal/Signal.js
2015-03-21 23:24:54 -04:00

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10 KiB
JavaScript

define(["Tone/core/Tone", "Tone/signal/WaveShaper"], function(Tone){
"use strict";
/**
* @class Constant audio-rate signal.
* Tone.Signal is a core component which allows for sample-accurate
* synchronization of many components. Tone.Signal can be scheduled
* with all of the functions available to AudioParams
*
* @constructor
* @extends {Tone.SignalBase}
* @param {number|AudioParam} [value=0] initial value or the AudioParam to control
* note that the signal has no output
* if an AudioParam is passed in.
* @param {Tone.Signal.Unit} [units=Number] unit the units the signal is in
* @example
* var signal = new Tone.Signal(10);
*/
Tone.Signal = function(value, units){
/**
* the units the signal is in
* @type {Tone.Signal.Type}
*/
this.units = this.defaultArg(units, Tone.Signal.Units.Number);
/**
* The node where the constant signal value is scaled.
* @type {AudioParam}
* @private
*/
this.output = this._scaler = this.context.createGain();
/**
* The node where the value is set.
* @type {AudioParam}
* @private
*/
this.input = this._value = this._scaler.gain;
if (value instanceof AudioParam){
this._scaler.connect(value);
//zero out the value
value.value = 0;
} else {
this.value = this.defaultArg(value, Tone.Signal.defaults.value);
}
//connect the constant 1 output to the node output
Tone.Signal._constant.chain(this._scaler);
};
Tone.extend(Tone.Signal, Tone.SignalBase);
/**
* The default values
* @type {Object}
* @static
* @const
*/
Tone.Signal.defaults = {
"value" : 0
};
/**
* The value of the signal.
* @memberOf Tone.Signal#
* @type {Tone.Time|Tone.Frequency|number}
* @name value
*/
Object.defineProperty(Tone.Signal.prototype, "value", {
get : function(){
return this._toUnits(this._value.value);
},
set : function(value){
var convertedVal = this._fromUnits(value);
//is this what you want?
this.cancelScheduledValues(0);
this._value.value = convertedVal;
}
});
/**
* @private
* @param {Tone.Time|Tone.Volume|Tone.Frequency|number|undefined} val the value to convert
* @return {number} the number which the value should be set to
*/
Tone.Signal.prototype._fromUnits = function(val){
switch(this.units){
case Tone.Signal.Units.Time:
return this.toSeconds(val);
case Tone.Signal.Units.Frequency:
return this.toFrequency(val);
case Tone.Signal.Units.Decibels:
return this.dbToGain(val);
case Tone.Signal.Units.Normal:
return Math.min(Math.max(val, 0), 1);
case Tone.Signal.Units.Audio:
return Math.min(Math.max(val, -1), 1);
default:
return val;
}
};
/**
* convert to the desired units
* @private
* @param {number} val the value to convert
* @return {number}
*/
Tone.Signal.prototype._toUnits = function(val){
switch(this.units){
case Tone.Signal.Units.Decibels:
return this.gainToDb(val);
default:
return val;
}
};
/**
* Schedules a parameter value change at the given time.
* @param {number} value
* @param {Tone.Time} time
* @returns {Tone.Signal} `this`
*/
Tone.Signal.prototype.setValueAtTime = function(value, time){
value = this._fromUnits(value);
this._value.setValueAtTime(value, this.toSeconds(time));
return this;
};
/**
* Creates a schedule point with the current value at the current time.
*
* @param {number=} now (optionally) pass the now value in
* @returns {Tone.Signal} `this`
*/
Tone.Signal.prototype.setCurrentValueNow = function(now){
now = this.defaultArg(now, this.now());
var currentVal = this._value.value;
this.cancelScheduledValues(now);
this._value.setValueAtTime(currentVal, now);
return this;
};
/**
* Schedules a linear continuous change in parameter value from the
* previous scheduled parameter value to the given value.
*
* @param {number} value
* @param {Tone.Time} endTime
* @returns {Tone.Signal} `this`
*/
Tone.Signal.prototype.linearRampToValueAtTime = function(value, endTime){
value = this._fromUnits(value);
this._value.linearRampToValueAtTime(value, this.toSeconds(endTime));
return this;
};
/**
* Schedules an exponential continuous change in parameter value from
* the previous scheduled parameter value to the given value.
*
* @param {number} value
* @param {Tone.Time} endTime
* @returns {Tone.Signal} `this`
*/
Tone.Signal.prototype.exponentialRampToValueAtTime = function(value, endTime){
value = this._fromUnits(value);
//can't go below a certain value
value = Math.max(0.00001, value);
// exponentialRampToValueAt cannot ever ramp from 0, apparently.
// More info: https://bugzilla.mozilla.org/show_bug.cgi?id=1125600#c2
if (this._value.value === 0) {
this._value.setValueAtTime(0.00001, this.now());
}
this._value.exponentialRampToValueAtTime(value, this.toSeconds(endTime));
return this;
};
/**
* Schedules an exponential continuous change in parameter value from
* the current time and current value to the given value.
*
* @param {number} value
* @param {Tone.Time} rampTime the time that it takes the
* value to ramp from it's current value
* @returns {Tone.Signal} `this`
* @example
* //exponentially ramp to the value 2 over 4 seconds.
* signal.exponentialRampToValueNow(2, 4);
*/
Tone.Signal.prototype.exponentialRampToValueNow = function(value, rampTime ){
var now = this.now();
this.setCurrentValueNow(now);
this.exponentialRampToValueAtTime(value, now + this.toSeconds(rampTime ));
return this;
};
/**
* Schedules an linear continuous change in parameter value from
* the current time and current value to the given value at the given time.
*
* @param {number} value
* @param {Tone.Time} rampTime the time that it takes the
* value to ramp from it's current value
* @returns {Tone.Signal} `this`
* @example
* //linearly ramp to the value 4 over 3 seconds.
* signal.linearRampToValueNow(4, 3);
*/
Tone.Signal.prototype.linearRampToValueNow = function(value, rampTime){
var now = this.now();
this.setCurrentValueNow(now);
this.linearRampToValueAtTime(value, now + this.toSeconds(rampTime));
return this;
};
/**
* Start exponentially approaching the target value at the given time with
* a rate having the given time constant.
* @param {number} value
* @param {Tone.Time} startTime
* @param {number} timeConstant
* @returns {Tone.Signal} `this`
*/
Tone.Signal.prototype.setTargetAtTime = function(value, startTime, timeConstant){
value = this._fromUnits(value);
// The value will never be able to approach without timeConstant > 0.
// http://www.w3.org/TR/webaudio/#dfn-setTargetAtTime, where the equation
// is described. 0 results in a division by 0.
timeConstant = Math.max(0.00001, timeConstant);
this._value.setTargetAtTime(value, this.toSeconds(startTime), timeConstant);
return this;
};
/**
* Sets an array of arbitrary parameter values starting at the given time
* for the given duration.
*
* @param {Array<number>} values
* @param {Tone.Time} startTime
* @param {Tone.Time} duration
* @returns {Tone.Signal} `this`
*/
Tone.Signal.prototype.setValueCurveAtTime = function(values, startTime, duration){
for (var i = 0; i < values.length; i++){
values[i] = this._fromUnits(values[i]);
}
this._value.setValueCurveAtTime(values, this.toSeconds(startTime), this.toSeconds(duration));
return this;
};
/**
* Cancels all scheduled parameter changes with times greater than or
* equal to startTime.
*
* @param {Tone.Time} startTime
* @returns {Tone.Signal} `this`
*/
Tone.Signal.prototype.cancelScheduledValues = function(startTime){
this._value.cancelScheduledValues(this.toSeconds(startTime));
return this;
};
/**
* Ramps to the given value over the duration of the rampTime.
* Automatically selects the best ramp type (exponential or linear)
* depending on the `units` of the signal
*
* @param {number} value
* @param {Tone.Time} rampTime the time that it takes the
* value to ramp from it's current value
* @returns {Tone.Signal} `this`
* @example
* //ramp to the value either linearly or exponentially
* //depending on the "units" value of the signal
* signal.rampTo(0, 10);
*/
Tone.Signal.prototype.rampTo = function(value, rampTime){
rampTime = this.defaultArg(rampTime, 0);
if (this.units === Tone.Signal.Units.Frequency || this.units === Tone.Signal.Units.BPM){
this.exponentialRampToValueNow(value, rampTime);
} else {
this.linearRampToValueNow(value, rampTime);
}
return this;
};
/**
* dispose and disconnect
* @returns {Tone.Signal} `this`
*/
Tone.Signal.prototype.dispose = function(){
Tone.prototype.dispose.call(this);
this._value = null;
this._scaler = null;
return this;
};
/**
* The units the Signal is in
* @enum {string}
*/
Tone.Signal.Units = {
/** The default type. */
Number : "number",
/** Tone.Time will be converted into seconds. */
Time : "time",
/** Tone.Frequency will be converted into hertz. */
Frequency : "frequency",
/** A Gain value. */
Gain : "gain",
/** Within normal range [0,1]. */
Normal : "normal",
/** Within normal range [-1,1]. */
Audio : "audio",
/** In decibels. */
Decibels : "db",
/** In half-step increments, i.e. 12 is an octave above the root. */
Interval : "interval",
/** Beats per minute. */
BPM : "bpm"
};
///////////////////////////////////////////////////////////////////////////
// STATIC
///////////////////////////////////////////////////////////////////////////
/**
* the constant signal generator
* @static
* @private
* @const
* @type {OscillatorNode}
*/
Tone.Signal._generator = null;
/**
* the signal generator waveshaper. makes the incoming signal
* only output 1 for all inputs.
* @static
* @private
* @const
* @type {Tone.WaveShaper}
*/
Tone.Signal._constant = null;
/**
* initializer function
*/
Tone._initAudioContext(function(audioContext){
Tone.Signal._generator = audioContext.createOscillator();
Tone.Signal._constant = new Tone.WaveShaper([1,1]);
Tone.Signal._generator.connect(Tone.Signal._constant);
Tone.Signal._generator.start(0);
Tone.Signal._generator.noGC();
});
return Tone.Signal;
});