tone/Tone/component/filter/FeedbackCombFilter.worklet.ts

A Web Audio framework for making interactive music in the browser.

import "../../core/worklet/SingleIOProcessor.worklet.js";
import "../../core/worklet/DelayLine.worklet.js";
import { registerProcessor } from "../../core/worklet/WorkletGlobalScope.js";

export const workletName = "feedback-comb-filter";

const feedbackCombFilter = /* javascript */ `
	class FeedbackCombFilterWorklet extends SingleIOProcessor {

		constructor(options) {
			super(options);
			this.delayLine = new DelayLine(this.sampleRate, options.channelCount || 2);
		}

		static get parameterDescriptors() {
			return [{
				name: "delayTime",
				defaultValue: 0.1,
				minValue: 0,
				maxValue: 1,
				automationRate: "k-rate"
			}, {
				name: "feedback",
				defaultValue: 0.5,
				minValue: 0,
				maxValue: 0.9999,
				automationRate: "k-rate"
			}];
		}

		generate(input, channel, parameters) {
			const delayedSample = this.delayLine.get(channel, parameters.delayTime * this.sampleRate);
			this.delayLine.push(channel, input + delayedSample * parameters.feedback);
			return delayedSample;
		}
	}
`;

registerProcessor(workletName, feedbackCombFilter);