tone/build/esm/source/Noise.js

import { ToneAudioBuffer } from "../core/context/ToneAudioBuffer.js";
import { optionsFromArguments } from "../core/util/Defaults.js";
import { assert } from "../core/util/Debug.js";
import { Source } from "../source/Source.js";
import { ToneBufferSource } from "./buffer/ToneBufferSource.js";
/**
 * Noise is a noise generator. It uses looped noise buffers to save on performance.
 * Noise supports the noise types: "pink", "white", and "brown". Read more about
 * colors of noise on [Wikipedia](https://en.wikipedia.org/wiki/Colors_of_noise).
 *
 * @example
 * // initialize the noise and start
 * const noise = new Tone.Noise("pink").start();
 * // make an autofilter to shape the noise
 * const autoFilter = new Tone.AutoFilter({
 * 	frequency: "8n",
 * 	baseFrequency: 200,
 * 	octaves: 8
 * }).toDestination().start();
 * // connect the noise
 * noise.connect(autoFilter);
 * // start the autofilter LFO
 * autoFilter.start();
 * @category Source
 */
export class Noise extends Source {
    constructor() {
        const options = optionsFromArguments(Noise.getDefaults(), arguments, [
            "type",
        ]);
        super(options);
        this.name = "Noise";
        /**
         * Private reference to the source
         */
        this._source = null;
        this._playbackRate = options.playbackRate;
        this.type = options.type;
        this._fadeIn = options.fadeIn;
        this._fadeOut = options.fadeOut;
    }
    static getDefaults() {
        return Object.assign(Source.getDefaults(), {
            fadeIn: 0,
            fadeOut: 0,
            playbackRate: 1,
            type: "white",
        });
    }
    /**
     * The type of the noise. Can be "white", "brown", or "pink".
     * @example
     * const noise = new Tone.Noise().toDestination().start();
     * noise.type = "brown";
     */
    get type() {
        return this._type;
    }
    set type(type) {
        assert(type in _noiseBuffers, "Noise: invalid type: " + type);
        if (this._type !== type) {
            this._type = type;
            // if it's playing, stop and restart it
            if (this.state === "started") {
                const now = this.now();
                this._stop(now);
                this._start(now);
            }
        }
    }
    /**
     * The playback rate of the noise. Affects
     * the "frequency" of the noise.
     */
    get playbackRate() {
        return this._playbackRate;
    }
    set playbackRate(rate) {
        this._playbackRate = rate;
        if (this._source) {
            this._source.playbackRate.value = rate;
        }
    }
    /**
     * internal start method
     */
    _start(time) {
        const buffer = _noiseBuffers[this._type];
        this._source = new ToneBufferSource({
            url: buffer,
            context: this.context,
            fadeIn: this._fadeIn,
            fadeOut: this._fadeOut,
            loop: true,
            onended: () => this.onstop(this),
            playbackRate: this._playbackRate,
        }).connect(this.output);
        this._source.start(this.toSeconds(time), Math.random() * (buffer.duration - 0.001));
    }
    /**
     * internal stop method
     */
    _stop(time) {
        if (this._source) {
            this._source.stop(this.toSeconds(time));
            this._source = null;
        }
    }
    /**
     * The fadeIn time of the amplitude envelope.
     */
    get fadeIn() {
        return this._fadeIn;
    }
    set fadeIn(time) {
        this._fadeIn = time;
        if (this._source) {
            this._source.fadeIn = this._fadeIn;
        }
    }
    /**
     * The fadeOut time of the amplitude envelope.
     */
    get fadeOut() {
        return this._fadeOut;
    }
    set fadeOut(time) {
        this._fadeOut = time;
        if (this._source) {
            this._source.fadeOut = this._fadeOut;
        }
    }
    _restart(time) {
        // TODO could be optimized by cancelling the buffer source 'stop'
        this._stop(time);
        this._start(time);
    }
    /**
     * Clean up.
     */
    dispose() {
        super.dispose();
        if (this._source) {
            this._source.disconnect();
        }
        return this;
    }
}
//--------------------
// THE NOISE BUFFERS
//--------------------
// Noise buffer stats
const BUFFER_LENGTH = 44100 * 5;
const NUM_CHANNELS = 2;
/**
 * Cache the noise buffers
 */
const _noiseCache = {
    brown: null,
    pink: null,
    white: null,
};
/**
 * The noise arrays. Generated on initialization.
 * borrowed heavily from https://github.com/zacharydenton/noise.js
 * (c) 2013 Zach Denton (MIT)
 */
const _noiseBuffers = {
    get brown() {
        if (!_noiseCache.brown) {
            const buffer = [];
            for (let channelNum = 0; channelNum < NUM_CHANNELS; channelNum++) {
                const channel = new Float32Array(BUFFER_LENGTH);
                buffer[channelNum] = channel;
                let lastOut = 0.0;
                for (let i = 0; i < BUFFER_LENGTH; i++) {
                    const white = Math.random() * 2 - 1;
                    channel[i] = (lastOut + 0.02 * white) / 1.02;
                    lastOut = channel[i];
                    channel[i] *= 3.5; // (roughly) compensate for gain
                }
            }
            _noiseCache.brown = new ToneAudioBuffer().fromArray(buffer);
        }
        return _noiseCache.brown;
    },
    get pink() {
        if (!_noiseCache.pink) {
            const buffer = [];
            for (let channelNum = 0; channelNum < NUM_CHANNELS; channelNum++) {
                const channel = new Float32Array(BUFFER_LENGTH);
                buffer[channelNum] = channel;
                let b0, b1, b2, b3, b4, b5, b6;
                b0 = b1 = b2 = b3 = b4 = b5 = b6 = 0.0;
                for (let i = 0; i < BUFFER_LENGTH; i++) {
                    const white = Math.random() * 2 - 1;
                    b0 = 0.99886 * b0 + white * 0.0555179;
                    b1 = 0.99332 * b1 + white * 0.0750759;
                    b2 = 0.969 * b2 + white * 0.153852;
                    b3 = 0.8665 * b3 + white * 0.3104856;
                    b4 = 0.55 * b4 + white * 0.5329522;
                    b5 = -0.7616 * b5 - white * 0.016898;
                    channel[i] =
                        b0 + b1 + b2 + b3 + b4 + b5 + b6 + white * 0.5362;
                    channel[i] *= 0.11; // (roughly) compensate for gain
                    b6 = white * 0.115926;
                }
            }
            _noiseCache.pink = new ToneAudioBuffer().fromArray(buffer);
        }
        return _noiseCache.pink;
    },
    get white() {
        if (!_noiseCache.white) {
            const buffer = [];
            for (let channelNum = 0; channelNum < NUM_CHANNELS; channelNum++) {
                const channel = new Float32Array(BUFFER_LENGTH);
                buffer[channelNum] = channel;
                for (let i = 0; i < BUFFER_LENGTH; i++) {
                    channel[i] = Math.random() * 2 - 1;
                }
            }
            _noiseCache.white = new ToneAudioBuffer().fromArray(buffer);
        }
        return _noiseCache.white;
    },
};
//# sourceMappingURL=Noise.js.map