[WIP] Add new audio-reactive palettes for smoothed FFT data

usermods/audioreactive/audio_reactive.cpp

@@ -71,7 +71,7 @@
   #define PLOT_PRINTF(x...)
 #endif
 
-#define MAX_PALETTES 3
+#define MAX_PALETTES 5
 
 static volatile bool disableSoundProcessing = false;      // if true, sound processing (FFT, filters, AGC) will be suspended. "volatile" as its shared between tasks.
 static uint8_t audioSyncEnabled = 0;          // bit field: bit 0 - send, bit 1 - receive (config value)
@@ -98,6 +98,9 @@ static bool udpSamplePeak = false;   // Boolean flag for peak. Set at the same t
 static unsigned long timeOfPeak = 0; // time of last sample peak detection.
 static uint8_t fftResult[NUM_GEQ_CHANNELS]= {0};// Our calculated freq. channel result table to be used by effects
 
+static float   paletteBandAvg[NUM_GEQ_CHANNELS] = {0.0f}; // Slowly smoothed band averages used only by audio palettes 3 & 4 (EMA, alpha=0.05 → ~400ms time constant at 20ms cycle)
+static constexpr float PALETTE_SMOOTHING = 0.05f;         // EMA smoothing factor for paletteBandAvg: 0.05 gives ~400ms time constant; increase for faster response, decrease for slower
+
 // TODO: probably best not used by receive nodes
 //static float agcSensitivity = 128;            // AGC sensitivity estimation, based on agc gain (multAgc). calculated by getSensitivity(). range 0..255
 
@@ -1683,6 +1686,7 @@ class AudioReactive : public Usermod {
       memset(fftCalc, 0, sizeof(fftCalc)); 
       memset(fftAvg, 0, sizeof(fftAvg)); 
       memset(fftResult, 0, sizeof(fftResult)); 
+      memset(paletteBandAvg, 0, sizeof(paletteBandAvg));
       for(int i=(init?0:1); i<NUM_GEQ_CHANNELS; i+=2) fftResult[i] = 16; // make a tiny pattern
       inputLevel = 128;                                    // reset level slider to default
       autoResetPeak();
@@ -1723,6 +1727,7 @@ class AudioReactive : public Usermod {
       // reset sound data
       volumeRaw = 0; volumeSmth = 0;
       for(int i=(init?0:1); i<NUM_GEQ_CHANNELS; i+=2) fftResult[i] = 16; // make a tiny pattern
+      memset(paletteBandAvg, 0, sizeof(paletteBandAvg));
       autoResetPeak();
       if (init) {
         if (udpSyncConnected) {   // close UDP sync connection (if open)
@@ -2223,6 +2228,69 @@ CRGB AudioReactive::getCRGBForBand(int x, int pal) {
       hsv = CHSV(fftResult[b], 255, map(fftResult[b], 0, 255, 30, 255));  // pick hue
       value = hsv;  // convert to R,G,B
       break;
+    // AI: below section was generated by an AI
+    case 3: {
+      // "Track Character" palette (palette index 3)
+      // Uses the spectral centroid of paletteBandAvg[] to derive a single hue that
+      // reflects the tonal balance of the music over the past ~400ms:          // softhack007 this statement is wrong
+      //   low centroid  (bass-heavy drop)     → warm red/orange  (hue ≈ 0)
+      //   mid centroid  (vocals/melody)        → green/cyan       (hue ≈ 80-120)
+      //   high centroid (cymbals/bright synth) → blue/purple      (hue ≈ 200)
+      // x (0-255) spreads palette positions ±30 hue units around that base hue.
+      static const float bandFreq[NUM_GEQ_CHANNELS] = {       // approximate centre frequency (Hz) of each GEQ channel
+        65, 107, 172, 258, 365, 495, 689, 969,
+        1270, 1658, 2153, 2713, 3359, 4091, 5792, 8182
+      };
+      float wSum = 0, tEnergy = 0;
+      for (int i = 0; i < NUM_GEQ_CHANNELS; i++) {
+        wSum += paletteBandAvg[i] * bandFreq[i];               // frequency-weighted energy
+        tEnergy += paletteBandAvg[i];                          // total energy
+      }
+      // centroid = energy-weighted average frequency; default to 500 Hz when signal is silent
+      float centroid = (tEnergy > 1.0f) ? (wSum / tEnergy) : 500.0f;
+      // Map centroid to hue on a log scale (human pitch perception is logarithmic).
+      // log2(60 Hz) ≈ 5.9,  log2(8000 Hz) ≈ 13.0  →  hue range 0..200 (red → blue-purple)
+      float logC = log2f(constrain(centroid, 60.0f, 8000.0f));   // softhack007 ToDO: use logf() instead of log2f()
+      uint8_t baseHue = (uint8_t)mapf(logC, 5.9f, 13.0f, 0.0f, 200.0f); // mapf() cannot produce negative results due to previous constrain() --> safe to directly cast to uint8_t
+      int8_t  hueSpread  = map(x, 0, 255, -30, 30);            // spread palette positions ±30 hue units // softhack007 ToDO: use CHSV32 with 16bit HUE
+      uint8_t saturation = (uint8_t)constrain((int)(tEnergy / 6.0f) + 180, 180, 255);  // louder = more saturated  // softhack007 WTF dude?
+      hsv = CHSV(baseHue + hueSpread, saturation, (uint8_t)constrain(x, 30, 255));
+      value = hsv;
+      break;
+    }
+    // AI: end
+    // AI: below section was generated by an AI
+    case 4: {
+      // "Spectral Balance" palette (palette index 4)
+      // Divides the spectrum into three broad bands and uses their energy ratio to derive hue:
+      //   bass dominant  (channels  0-3,  ~43-301 Hz)  → warm hue  ≈ 20  (red/orange)
+      //   mid dominant   (channels  4-9,  ~301-1895 Hz) → green hue ≈ 110 (green/cyan)
+      //   high dominant  (channels 10-15, ~1895-9259 Hz)→ cool hue  ≈ 190 (blue/violet)
+      // x (0-255) spreads palette positions ±25 hue units around that weighted hue,
+      // giving a smooth colour band rather than a single flat colour.
+      float bassEnergy = 0, midEnergy = 0, highEnergy = 0;
+      for (int i = 0;  i < 4;  i++) bassEnergy += paletteBandAvg[i];  // sub-bass + bass
+      for (int i = 4;  i < 10; i++) midEnergy  += paletteBandAvg[i];  // midrange
+      for (int i = 10; i < 16; i++) highEnergy += paletteBandAvg[i];  // high-mid + high
+      float total = bassEnergy + midEnergy + highEnergy;
+      if (total < 1.0f) total = 1.0f;                          // avoid division by zero when silent
+      float bassRatio = bassEnergy / total;                     // fraction of energy in bass band
+      float midRatio  = midEnergy  / total;
+      float highRatio = highEnergy / total;
+      // Weighted hue: pure bass→20, pure mid→110, pure high→190
+      int weightedHue = roundf(bassRatio * 20.0f + midRatio * 110.0f + highRatio * 190.0f);
+      uint8_t hue     = min(255, max(0, weightedHue));     // clamp to [0...255]
+      // Saturation: dominated spectrum (one band clearly wins) → high sat; balanced → lower sat
+      float   maxRatio = max(bassRatio, max(midRatio, highRatio));
+      uint8_t sat      = (uint8_t)constrain((int)(maxRatio * 255.0f * 1.5f), 180, 255); // softhack007 OMG,  WTF?
+      int8_t  hueOffset = map(x, 0, 255, -25, 25);             // spread palette positions ±25 hue units // softhack007 ToDO: use CHSV32 with 16bit HUE
+      // brightness: minimum 30, boosted by overall loudness and palette position
+      uint8_t val = (uint8_t)constrain((int)(total / 8.0f) + (int)map(x, 0, 255, 30, 255), 30, 255);
+      hsv = CHSV(hue + hueOffset, sat, val);
+      value = hsv;
+      break;
+    }
+    // AI: end
     default:
       if (x == 1) {
         value = CRGB(fftResult[10]/2, fftResult[4]/2, fftResult[0]/2);
@@ -2240,6 +2308,17 @@ void AudioReactive::fillAudioPalettes() {
   if (!palettes) return;
   size_t lastCustPalette = customPalettes.size();
   if (int(lastCustPalette) >= palettes) lastCustPalette -= palettes;
+
+  // AI: below section was generated by an AI
+  // Update slowly-smoothed band averages used by palettes 3 & 4.
+  // Alpha=PALETTE_SMOOTHING gives ~400ms time constant at a 20ms update cycle,
+  // so palette colours reflect the overall tonal character of the music rather than
+  // reacting to individual beats (which would appear "twitchy").
+  for (int i = 0; i < NUM_GEQ_CHANNELS; i++) {
+    paletteBandAvg[i] += PALETTE_SMOOTHING * ((float)fftResult[i] - paletteBandAvg[i]); // BUG: this IIR filter assumes 20ms activation rate (which is totally wrong)
+  }
+  // AI: end
+
   for (int pal=0; pal<palettes; pal++) {
     uint8_t tcp[16];  // Needs to be 4 times however many colors are being used.
                       // 3 colors = 12, 4 colors = 16, etc.