Add FFT ripple mode

src/backend/pattern/fftRipple.ts

@@ -0,0 +1,73 @@
+import { IColorGetter, IColorMapper, IArrColor } from 'src/typings'
+import { callIndexedGetter } from './mappers'
+import { pixelsCount, hueToColor } from '../shared'
+import { settings } from 'src/settings'
+import { audioState } from '../wsAudio'
+
+interface Ripple {
+	pos: number
+	radius: number
+	brightness: number
+	hue: number
+}
+
+let ripples: Ripple[] = []
+let lastTime = Date.now()
+let averages: number[] = []
+const attenuation = 0.9
+const speed = 60
+
+function spawnRipple(bin: number, mag: number) {
+	const hue = (bin / audioState.bins.length) * 270
+	ripples.push({
+		pos: (bin / audioState.bins.length) * pixelsCount,
+		radius: 1,
+		brightness: Math.min(1, mag),
+		hue,
+	})
+}
+
+function update(time: number) {
+	const dt = (time - lastTime) * settings.effectSpeed
+	lastTime = time
+	const bins = audioState.bins
+	if (bins && bins.length) {
+		if (averages.length !== bins.length) averages = bins.slice()
+		for (let i = 0; i < bins.length; i++) {
+			const m = bins[i]
+			averages[i] = averages[i] * 0.9 + m * 0.1
+			if (m > averages[i] * 1.5) spawnRipple(i, m)
+		}
+	}
+	ripples.forEach(r => {
+		r.radius += (speed * dt) / 1000
+		r.brightness *= Math.pow(attenuation, dt / 16)
+	})
+	ripples = ripples.filter(r => r.brightness > 0.05)
+}
+
+export const getFftRippleColor: IColorGetter = (index, time) => {
+	if (index === 0) update(time)
+	let r = 0
+	let g = 0
+	let b = 0
+	for (const ripple of ripples) {
+		const dist = Math.abs(index - ripple.pos)
+		if (dist <= ripple.radius) {
+			const intensity = ripple.brightness * (1 - dist / ripple.radius)
+			const { r: rr, g: gg, b: bb } = hueToColor(ripple.hue).rgb()
+			r += rr * intensity
+			g += gg * intensity
+			b += bb * intensity
+		}
+	}
+	return [Math.min(255, Math.round(r)), Math.min(255, Math.round(g)), Math.min(255, Math.round(b))]
+}
+
+export function resetFftRipples() {
+	ripples = []
+	lastTime = Date.now()
+	averages = []
+}
+
+export const fftRippleMapper: IColorMapper = () => callIndexedGetter(getFftRippleColor)

src/backend/pattern/index.ts

@@ -10,6 +10,7 @@ import { getWaveColor } from './wave'
 import { getHeartbeatColor, getStrobeColor, getPulseColor, getGradientPulseColor, getMultiPulseColor } from './extra'
 import { rippleMapper } from './ripple'
 import { musicRippleMapper } from './musicRipple'
+import { fftRippleMapper } from './fftRipple'
 import { createIndexedMapper, createFlatMapper } from './mappers'
 
 const transitionDuration = 250
@@ -39,6 +40,7 @@ const mappers: Record<IMode, IColorMapper> = {
 	[IMode.MultiPulse]: createIndexedMapper(getMultiPulseColor),
 	[IMode.Ripple]: rippleMapper,
 	[IMode.MusicRipple]: musicRippleMapper,
+	[IMode.FftRipple]: fftRippleMapper,
 }
 
 export function getPixels(mode: IMode): IArrColor[][] {

src/backend/wsAudio.ts

@@ -6,9 +6,10 @@ export interface AudioState {
 	hue: number
 	level: number
 	freq: number
+	bins: number[]
 }
 
-export const audioState: AudioState = { hue: 0, level: 0, freq: 0 }
+export const audioState: AudioState = { hue: 0, level: 0, freq: 0, bins: [] }
 
 export function startAudioServer(port = 8081) {
 	const wss = new WebSocketServer({ port })
@@ -24,6 +25,7 @@ export function processAudio(buffer: Buffer, sampleRate = 44100) {
 	const input = Array.from(samples, s => s / 32768)
 	const spectrum = fft(input)
 	const mags = util.fftMag(spectrum)
+	audioState.bins = mags.slice(0, mags.length / 2)
 	let max = 0
 	let idx = 0
 	for (let i = 1; i < mags.length / 2; i++) {

src/typings.ts

@@ -27,6 +27,7 @@ export enum IMode {
 	MultiPulse,
 	Ripple,
 	MusicRipple,
+	FftRipple,
 }
 
 export interface ISettings {

tests/fftRipple.test.ts

@@ -0,0 +1,17 @@
+import { getFftRippleColor, resetFftRipples } from '../src/backend/pattern/fftRipple'
+import { audioState } from '../src/backend/wsAudio'
+
+beforeEach(() => {
+  resetFftRipples()
+  audioState.bins = Array(8).fill(0)
+})
+
+describe('fft ripple pattern', () => {
+  test('spawns ripple on spike', () => {
+  audioState.bins[0] = 2
+  ;(getFftRippleColor as any)(0, 0)
+  audioState.bins[0] = 10
+  const color = (getFftRippleColor as any)(0, 16)
+  expect(color).not.toEqual([0, 0, 0])
+  })
+})