Added arpeggiato, fixed notes. TODO: Fix menu options for arpeggio. Persistent config/save+load option

sketch/sketch.ino

@@ -28,12 +28,19 @@ Adafruit_SSD1306 display(OLED_W, OLED_H, &Wire);
 
 // Modes
 int mode = 0;
-  String mode_names[4] = {"Vol", "Sou", "Oct", "Env"};
+String mode_names[7] = { "Vol", "Sou", "Oct", "Env", "Arp", "ArpΔ", "Arp"};
 int mode_count = sizeof(mode_names) / sizeof(mode_names[0]);
 
 // Octave
 int octave = 2;
 
+// Arpeggio
+//int arp_pattern[5] = {1 ,3 ,5 ,3 ,1 };
+int arp_pattern[5] = {0 ,4 ,7 ,3 ,1 };
+int arpeggio = 1;  // 0 = Off, 1 =
+int arp_notes = 3; // Now many notes to arpeggiate
+int arp_delay = 150; // 300 ms
+
 
 // ---- Audio ----
 //constexpr uint32_t SAMPLE_RATE = 96000;
@@ -80,10 +87,13 @@ void initNotes() {
 struct Voice {
   bool active = false;
   float freq = 0;
+  float startFreq = 0;
   float phase1 = 0;
   float phase2 = 0;
   float env = 0;
   float amp = 0;
+  long  arp_time = 0;
+  int   arp_position = 0;
 };
 
 Voice voices[MAX_VOICES];
@@ -92,8 +102,11 @@ void noteOn(float freq) {
   for (auto &v : voices) {
     if (!v.active) {
       v.active = true;
-      v.freq = freq*(funcKey ? 1.25f : 1.0f);
+      v.freq = freq;
+      v.startFreq = freq;
       v.env = VOL;
+      v.arp_time = millis();
+      v.arp_position = 0;
       v.phase1 = 0.5f;
       v.phase2 = 0.5f;
       return;
@@ -103,7 +116,7 @@ void noteOn(float freq) {
 
 void noteOff(float freq) {
   for (auto &v : voices) {
-    if (v.active && fabs(v.freq - freq) < 0.01f) {
+    if (v.active && fabs(v.startFreq - freq) < 0.01f) {
       v.active = false;
     }
   }
@@ -146,11 +159,16 @@ int genWaveTable(){
   }
   return 0;
 }
+
+
+float transposeSemitones(float freq, int semitones) {
+    return freq * powf(2.0f, semitones / 12.0f);
+}
 /* =========================================================
    SYNTH STREAM
    ========================================================= */
 
-class JunoStream : public Stream {
+class SynthStream : public Stream {
 public:
   uint8_t frame[4];
   uint8_t index = 4;
@@ -167,7 +185,9 @@ public:
   float scope[128]{};
   int scopeIndex = 0;
 
-  int available() override { return 4; }
+  int available() override {
+    return 4;
+  }
 
   int read() override {
     if (index >= 4) {
@@ -177,8 +197,12 @@ public:
     return frame[index++];
   }
 
-  int peek() override { return -1; }
+  int peek() override {
-  size_t write(uint8_t) override { return 0; }
+    return -1;
+  }
+  size_t write(uint8_t) override {
+    return 0;
+  }
 
 private:
   void generate() {
@@ -188,6 +212,13 @@ private:
       if (!v.active) continue;
       float osc = 0.0f;
 
+
+      if (arpeggio>0 && (millis()-v.arp_time)>arp_delay){
+        v.arp_time = millis();
+        v.arp_position++;
+        v.arp_position = v.arp_position % arp_notes;
+        v.freq = transposeSemitones(v.startFreq, arp_pattern[v.arp_position]);
+      }
       // Defined voices
       switch (sound) {
         // Saw+Sine
@@ -228,10 +259,13 @@ private:
 
       mix += osc * v.amp;
     }
+    // Handle reverb
+    mix = (handleReverb(mix) + mix) / 2.0f;
+
 
     lp += cutoff * (mix - lp);
     float out = lp * 0.4f;
-    //out = (handleReverb(out)+out)/2.0f;
+
 
     int r = (delayIndex - 480 + DELAY_SAMPLES) % DELAY_SAMPLES;
     float ch = out + delayL[r] * 0.6f;
@@ -256,7 +290,7 @@ private:
    ========================================================= */
 
 I2SStream i2s;
-JunoStream synth;
+SynthStream synth;
 StreamCopy copier(i2s, synth);
 
 /* =========================================================
@@ -269,7 +303,7 @@ uint16_t scanMatrix() {
 
   for (int x = 0; x < 4; x++) {
     digitalWrite(X_PINS[x], HIGH);
-    delayMicroseconds(5);
+    delayMicroseconds(10);
 
     for (int y = 0; y < 4; y++) {
       if (digitalRead(Y_PINS[y])) {
@@ -311,7 +345,8 @@ void handleInputs(){
         if (keys & (1 << 13)) {
           switch (mode) {
             case 0:  // Volume
-              if(VOL > 0.1f){ VOL-=0.1f; } break;
+              if (VOL > 0.1f) { VOL -= 0.1f; }
+              break;
             case 1:  // Sound
               sound = sound - 1;
               if (sound < 0) { sound = sound_count - 1; }
@@ -396,8 +431,7 @@ void drawScope() {
       mid - synth.scope[i1] * scale * height,
       x + 1,
       mid - synth.scope[i2] * scale * height,
-      SSD1306_WHITE
+      SSD1306_WHITE);
-    );
   }
 }
 
@@ -432,8 +466,6 @@ void drawInfo(){
   display.print(mode_names[mode]);
   display.setCursor(90, 18);
   display.print("Oct:" + String(octave));
-
-
 }
 
 void updateOLED(uint16_t keys) {