@azgaar/tone
Version:
A fork of Web Audio framework for making interactive music in the browser.
91 lines • 3.02 kB
JavaScript
import { optionsFromArguments } from "../../core/util/Defaults";
import { Envelope } from "./Envelope";
import { Scale } from "../../signal/Scale";
import { Pow } from "../../signal/Pow";
import { assertRange } from "../../core/util/Debug";
/**
* FrequencyEnvelope is an [[Envelope]] which ramps between [[baseFrequency]]
* and [[octaves]]. It can also have an optional [[exponent]] to adjust the curve
* which it ramps.
* @example
* const oscillator = new Tone.Oscillator().toDestination().start();
* const freqEnv = new Tone.FrequencyEnvelope({
* attack: 0.2,
* baseFrequency: "C2",
* octaves: 4
* });
* freqEnv.connect(oscillator.frequency);
* freqEnv.triggerAttack();
* @category Component
*/
export class FrequencyEnvelope extends Envelope {
constructor() {
super(optionsFromArguments(FrequencyEnvelope.getDefaults(), arguments, ["attack", "decay", "sustain", "release"]));
this.name = "FrequencyEnvelope";
const options = optionsFromArguments(FrequencyEnvelope.getDefaults(), arguments, ["attack", "decay", "sustain", "release"]);
this._octaves = options.octaves;
this._baseFrequency = this.toFrequency(options.baseFrequency);
this._exponent = this.input = new Pow({
context: this.context,
value: options.exponent
});
this._scale = this.output = new Scale({
context: this.context,
min: this._baseFrequency,
max: this._baseFrequency * Math.pow(2, this._octaves),
});
this._sig.chain(this._exponent, this._scale);
}
static getDefaults() {
return Object.assign(Envelope.getDefaults(), {
baseFrequency: 200,
exponent: 1,
octaves: 4,
});
}
/**
* The envelope's minimum output value. This is the value which it
* starts at.
*/
get baseFrequency() {
return this._baseFrequency;
}
set baseFrequency(min) {
const freq = this.toFrequency(min);
assertRange(freq, 0);
this._baseFrequency = freq;
this._scale.min = this._baseFrequency;
// update the max value when the min changes
this.octaves = this._octaves;
}
/**
* The number of octaves above the baseFrequency that the
* envelope will scale to.
*/
get octaves() {
return this._octaves;
}
set octaves(octaves) {
this._octaves = octaves;
this._scale.max = this._baseFrequency * Math.pow(2, octaves);
}
/**
* The envelope's exponent value.
*/
get exponent() {
return this._exponent.value;
}
set exponent(exponent) {
this._exponent.value = exponent;
}
/**
* Clean up
*/
dispose() {
super.dispose();
this._exponent.dispose();
this._scale.dispose();
return this;
}
}
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