mirror of
https://github.com/Tonejs/Tone.js
synced 2024-11-15 16:17:58 +00:00
85 lines
2.2 KiB
TypeScript
85 lines
2.2 KiB
TypeScript
import { Time } from "../../core/type/Units";
|
|
import { InputNode, OutputNode, ToneAudioNode, ToneAudioNodeOptions } from "../../core/context/ToneAudioNode";
|
|
import { optionsFromArguments } from "../../core/util/Defaults";
|
|
import { OnePoleFilter } from "../filter/OnePoleFilter";
|
|
import { Abs } from "../../signal/Abs";
|
|
|
|
export interface FollowerOptions extends ToneAudioNodeOptions {
|
|
smoothing: Time;
|
|
}
|
|
|
|
/**
|
|
* Follower is a simple envelope follower.
|
|
* It's implemented by applying a lowpass filter to the absolute value of the incoming signal.
|
|
* ```
|
|
* +-----+ +---------------+
|
|
* Input +--> Abs +----> OnePoleFilter +--> Output
|
|
* +-----+ +---------------+
|
|
* ```
|
|
* @category Component
|
|
*/
|
|
export class Follower extends ToneAudioNode<FollowerOptions> {
|
|
|
|
readonly name: string = "Follower";
|
|
|
|
readonly input: InputNode;
|
|
readonly output: OutputNode;
|
|
|
|
/**
|
|
* Private reference to the smoothing parameter
|
|
*/
|
|
private _smoothing: Time;
|
|
|
|
/**
|
|
* The lowpass filter
|
|
*/
|
|
private _lowpass: OnePoleFilter;
|
|
|
|
/**
|
|
* The absolute value
|
|
*/
|
|
private _abs: Abs;
|
|
|
|
/**
|
|
* @param smoothing The rate of change of the follower.
|
|
*/
|
|
constructor(smoothing?: Time);
|
|
constructor(options?: Partial<FollowerOptions>);
|
|
constructor() {
|
|
super(optionsFromArguments(Follower.getDefaults(), arguments, ["smoothing"]));
|
|
const options = optionsFromArguments(Follower.getDefaults(), arguments, ["smoothing"]);
|
|
|
|
this._abs = this.input = new Abs({ context: this.context });
|
|
this._lowpass = this.output = new OnePoleFilter({
|
|
context: this.context,
|
|
frequency: 1 / this.toSeconds(options.smoothing),
|
|
type: "lowpass"
|
|
});
|
|
this._abs.connect(this._lowpass);
|
|
this._smoothing = options.smoothing;
|
|
}
|
|
|
|
static getDefaults(): FollowerOptions {
|
|
return Object.assign(ToneAudioNode.getDefaults(), {
|
|
smoothing: 0.05
|
|
});
|
|
}
|
|
|
|
/**
|
|
* The amount of time it takes a value change to arrive at the updated value.
|
|
*/
|
|
get smoothing(): Time {
|
|
return this._smoothing;
|
|
}
|
|
set smoothing(smoothing) {
|
|
this._smoothing = smoothing;
|
|
this._lowpass.frequency = 1 / this.toSeconds(this.smoothing);
|
|
}
|
|
|
|
dispose(): this {
|
|
super.dispose();
|
|
this._abs.dispose();
|
|
this._lowpass.dispose();
|
|
return this;
|
|
}
|
|
}
|