Add devices from @zenfs/devices

package.json

@@ -11,6 +11,9 @@
 	"type": "module",
 	"homepage": "https://github.com/zen-fs/dom",
 	"author": "James Prevett <[email protected]> (https://jamespre.dev)",
+	"contributors": [
+		"David Konsumer <[email protected]>"
+	],
 	"license": "MIT",
 	"repository": {
 		"type": "git",

src/devices/audioworklet.d.ts

@@ -0,0 +1,32 @@
+/* Types pulled from @types/audioworklet */
+
+/* eslint-disable no-var, @typescript-eslint/no-explicit-any */
+
+/** [MDN Reference](https://developer.mozilla.org/docs/Web/API/AudioWorkletProcessor) */
+interface AudioWorkletProcessor {
+	/** [MDN Reference](https://developer.mozilla.org/docs/Web/API/AudioWorkletProcessor/port) */
+	readonly port: MessagePort;
+
+	process(inputs: Float32Array[][], outputs: Float32Array[][], parameters: Record<string, Float32Array>): boolean;
+}
+
+declare var AudioWorkletProcessor: {
+	prototype: AudioWorkletProcessor;
+	new (): AudioWorkletProcessor;
+};
+
+interface AudioWorkletProcessorConstructor {
+	new (options: any): AudioWorkletProcessor;
+}
+
+/** [MDN Reference](https://developer.mozilla.org/docs/Web/API/AudioWorkletGlobalScope/currentFrame) */
+declare var currentFrame: number;
+
+/** [MDN Reference](https://developer.mozilla.org/docs/Web/API/AudioWorkletGlobalScope/currentTime) */
+declare var currentTime: number;
+
+/** [MDN Reference](https://developer.mozilla.org/docs/Web/API/AudioWorkletGlobalScope/sampleRate) */
+declare var sampleRate: number;
+
+/** [MDN Reference](https://developer.mozilla.org/docs/Web/API/AudioWorkletGlobalScope/registerProcessor) */
+declare function registerProcessor(name: string, processor: AudioWorkletProcessorConstructor): void;

src/devices/dsp.ts

@@ -0,0 +1,72 @@
+/* Credit: David Konsumer */
+import type { DeviceDriver, DeviceFile } from '@zenfs/core';
+import './audioworklet.d.ts';
+
+if ('AudioWorkletProcessor' in globalThis) {
+	class Dsp extends AudioWorkletProcessor {
+		protected buffer?: Float32Array;
+
+		public constructor() {
+			super();
+			this.port.onmessage = ({ data }: MessageEvent<Float32Array>) => {
+				this.buffer = new Float32Array(data);
+			};
+		}
+
+		public process(inputs: Float32Array[][], outputs: Float32Array[][]): boolean {
+			if (this.buffer && this.buffer.byteLength >= 128) {
+				outputs[0][0].set(this.buffer.slice(0, 128));
+				this.buffer = this.buffer.slice(128);
+			}
+			return true;
+		}
+
+		public static get parameterDescriptors() {
+			return [
+				{
+					name: 'gain',
+					defaultValue: 1,
+					minValue: 0,
+					maxValue: 1,
+					automationRate: 'a-rate',
+				},
+			];
+		}
+	}
+
+	registerProcessor('zenfs:dsp', Dsp);
+}
+
+export interface DspOptions {
+	audioContext?: AudioContext;
+}
+
+export async function dsp(options: DspOptions = {}): Promise<DeviceDriver<AudioWorkletNode>> {
+	const context = options.audioContext || new AudioContext();
+
+	await context.audioWorklet.addModule(import.meta.url);
+
+	const dsp = new AudioWorkletNode(context, 'zenfs:dsp');
+	dsp.connect(context.destination);
+
+	// add a click-handler to resume (due to web security) https://goo.gl/7K7WLu
+	document.addEventListener('click', () => {
+		if (context.state != 'running') {
+			void context.resume().catch(() => {});
+		}
+	});
+
+	return {
+		name: 'dsp',
+		init() {
+			return { data: dsp, major: 14, minor: 3 };
+		},
+		read() {
+			return 0;
+		},
+		write(file: DeviceFile, data: Uint8Array): number {
+			dsp.port.postMessage(data.buffer);
+			return data.byteLength;
+		},
+	};
+}

src/devices/framebuffer.ts

@@ -0,0 +1,39 @@
+/* Credit: David Konsumer */
+import { Errno, ErrnoError } from '@zenfs/core';
+import type { DeviceDriver, DeviceFile } from '@zenfs/core';
+
+export interface FramebufferOptions {
+	canvas?: HTMLCanvasElement | null;
+}
+
+let framebufferN = 0;
+
+export function framebuffer({ canvas }: FramebufferOptions = {}): DeviceDriver<CanvasRenderingContext2D> {
+	if (!canvas) {
+		canvas = document.createElement('canvas');
+		document.body.appendChild(canvas);
+	}
+	const ctx = canvas.getContext('2d');
+
+	if (!ctx) {
+		throw new ErrnoError(Errno.EIO, 'Could not get context from canvas whilst initializing frame buffer.');
+	}
+
+	return {
+		name: 'framebuffer',
+		init() {
+			return { data: ctx, major: 29, minor: framebufferN++ };
+		},
+		read() {
+			return 0;
+		},
+		write(file: DeviceFile, data: Uint8Array) {
+			if (data.byteLength < 4 * canvas.width * canvas.height) {
+				return 0;
+			}
+			const imageData = new ImageData(new Uint8ClampedArray(data), canvas.width, canvas.height);
+			ctx.putImageData(imageData, 0, 0);
+			return data.byteLength;
+		},
+	};
+}

src/devices/index.ts

@@ -0,0 +1,2 @@
+export * from './dsp.js';
+export * from './framebuffer.js';