tone/build/esm/effect/PitchShift.js

import { FeedbackEffect } from "./FeedbackEffect.js";
import { optionsFromArguments } from "../core/util/Defaults.js";
import { LFO } from "../source/oscillator/LFO.js";
import { Delay } from "../core/context/Delay.js";
import { CrossFade } from "../component/channel/CrossFade.js";
import { Signal } from "../signal/Signal.js";
import { readOnly } from "../core/util/Interface.js";
import { intervalToFrequencyRatio } from "../core/type/Conversions.js";
/**
 * PitchShift does near-realtime pitch shifting to the incoming signal.
 * The effect is achieved by speeding up or slowing down the delayTime
 * of a DelayNode using a sawtooth wave.
 * Algorithm found in [this pdf](http://dsp-book.narod.ru/soundproc.pdf).
 * Additional reference by [Miller Pucket](http://msp.ucsd.edu/techniques/v0.11/book-html/node115.html).
 * @category Effect
 */
export class PitchShift extends FeedbackEffect {
    constructor() {
        const options = optionsFromArguments(PitchShift.getDefaults(), arguments, ["pitch"]);
        super(options);
        this.name = "PitchShift";
        this._frequency = new Signal({ context: this.context });
        this._delayA = new Delay({
            maxDelay: 1,
            context: this.context,
        });
        this._lfoA = new LFO({
            context: this.context,
            min: 0,
            max: 0.1,
            type: "sawtooth",
        }).connect(this._delayA.delayTime);
        this._delayB = new Delay({
            maxDelay: 1,
            context: this.context,
        });
        this._lfoB = new LFO({
            context: this.context,
            min: 0,
            max: 0.1,
            type: "sawtooth",
            phase: 180,
        }).connect(this._delayB.delayTime);
        this._crossFade = new CrossFade({ context: this.context });
        this._crossFadeLFO = new LFO({
            context: this.context,
            min: 0,
            max: 1,
            type: "triangle",
            phase: 90,
        }).connect(this._crossFade.fade);
        this._feedbackDelay = new Delay({
            delayTime: options.delayTime,
            context: this.context,
        });
        this.delayTime = this._feedbackDelay.delayTime;
        readOnly(this, "delayTime");
        this._pitch = options.pitch;
        this._windowSize = options.windowSize;
        // connect the two delay lines up
        this._delayA.connect(this._crossFade.a);
        this._delayB.connect(this._crossFade.b);
        // connect the frequency
        this._frequency.fan(this._lfoA.frequency, this._lfoB.frequency, this._crossFadeLFO.frequency);
        // route the input
        this.effectSend.fan(this._delayA, this._delayB);
        this._crossFade.chain(this._feedbackDelay, this.effectReturn);
        // start the LFOs at the same time
        const now = this.now();
        this._lfoA.start(now);
        this._lfoB.start(now);
        this._crossFadeLFO.start(now);
        // set the initial value
        this.windowSize = this._windowSize;
    }
    static getDefaults() {
        return Object.assign(FeedbackEffect.getDefaults(), {
            pitch: 0,
            windowSize: 0.1,
            delayTime: 0,
            feedback: 0,
        });
    }
    /**
     * Repitch the incoming signal by some interval (measured in semi-tones).
     * @example
     * const pitchShift = new Tone.PitchShift().toDestination();
     * const osc = new Tone.Oscillator().connect(pitchShift).start().toDestination();
     * pitchShift.pitch = -12; // down one octave
     * pitchShift.pitch = 7; // up a fifth
     */
    get pitch() {
        return this._pitch;
    }
    set pitch(interval) {
        this._pitch = interval;
        let factor = 0;
        if (interval < 0) {
            this._lfoA.min = 0;
            this._lfoA.max = this._windowSize;
            this._lfoB.min = 0;
            this._lfoB.max = this._windowSize;
            factor = intervalToFrequencyRatio(interval - 1) + 1;
        }
        else {
            this._lfoA.min = this._windowSize;
            this._lfoA.max = 0;
            this._lfoB.min = this._windowSize;
            this._lfoB.max = 0;
            factor = intervalToFrequencyRatio(interval) - 1;
        }
        this._frequency.value = factor * (1.2 / this._windowSize);
    }
    /**
     * The window size corresponds roughly to the sample length in a looping sampler.
     * Smaller values are desirable for a less noticeable delay time of the pitch shifted
     * signal, but larger values will result in smoother pitch shifting for larger intervals.
     * A nominal range of 0.03 to 0.1 is recommended.
     */
    get windowSize() {
        return this._windowSize;
    }
    set windowSize(size) {
        this._windowSize = this.toSeconds(size);
        this.pitch = this._pitch;
    }
    dispose() {
        super.dispose();
        this._frequency.dispose();
        this._delayA.dispose();
        this._delayB.dispose();
        this._lfoA.dispose();
        this._lfoB.dispose();
        this._crossFade.dispose();
        this._crossFadeLFO.dispose();
        this._feedbackDelay.dispose();
        return this;
    }
}
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