Flamingo/FM/FM.ino

#include <MozziGuts.h>
#include <mozzi_midi.h>
#include <Oscil.h> // oscillator 
#include <tables/cos2048_int8.h> // table for Oscils to play
#include <Smooth.h>
#include <AutoMap.h> // maps unpredictable inputs to a range
#include <MIDIUSB.h>
#include <MIDI.h>

MIDI_CREATE_DEFAULT_INSTANCE();

#define CONTROL_RATE 64
#define MIDI_CHANNEL 3

bool gate = 0;
byte noteBuffer[8];
byte bufferIndex = 0;

// desired intensity max and min, for AutoMap, note they're inverted for reverse dynamics
const int MIN_INTENSITY = 700;
const int MAX_INTENSITY = 10;

// desired mod speed max and min, for AutoMap, note they're inverted for reverse dynamics
const int MIN_MOD_SPEED = 10000;
const int MAX_MOD_SPEED = 1;

const int MIN = 10;
const int MAX = 1;

const int MIN_2 = 1;
const int MAX_2 = 15;

AutoMap kMapIntensity(0,1023,MIN_INTENSITY,MAX_INTENSITY);
AutoMap kMapModSpeed(0,1023,MIN_MOD_SPEED,MAX_MOD_SPEED);
AutoMap mapThis(0,1023,MIN,MAX);
AutoMap mapThisToo(0,1023,MIN_2,MAX_2);

//Mapping the knob pins
const int CONTROLL1 = 0;
const int CONTROLL2 = 1;
const int CONTROLL3 = 2;
const int CONTROLL4 = 3;

Oscil<COS2048_NUM_CELLS, AUDIO_RATE> aCarrier(COS2048_DATA);
Oscil<COS2048_NUM_CELLS, AUDIO_RATE> aModulator(COS2048_DATA);
Oscil<COS2048_NUM_CELLS, CONTROL_RATE> kIntensityMod(COS2048_DATA);

int mod_ratio = 5; // brightness (harmonics)
long fm_intensity; // carries control info from updateControl to updateAudio

// smoothing for intensity to remove clicks on transitions
float smoothness = 0.95f;
Smooth <long> aSmoothIntensity(smoothness);

int carrier_freq;

void noteOn(byte channel, byte note, byte velocity) {
  if (channel == MIDI_CHANNEL) {
    gate = 1;
    updateBuffer(note, gate);
    //playNote(); // this is called from within buffer update
  }
}

void noteOff(byte channel, byte note, byte velocity) {
  if (channel == MIDI_CHANNEL) {
    gate = 0;
    updateBuffer(note, gate);
  }
}

void updateBuffer(byte bNote, bool bGate) {
  if (bGate == 1) {
    noteBuffer[bufferIndex] = bNote;
    playNote();
    bufferIndex++;
  }
  if (bGate == 0) { // && bufferIndex != 0
    for (int i = 0; i <= bufferIndex; i++) {
      if (noteBuffer[i] == bNote) {
        // Removing the note from the array and shifting everything to close the gap 
        for (int n = i; n <= bufferIndex; n++) {
          noteBuffer[n] = noteBuffer[n + 1]; // what happens if it's the last note in buffer?
        }      
        if (i == bufferIndex) { //this does not fire
          bufferIndex--;
          gate = 1;
          playNote();          
        } else { //this does fire
          bufferIndex--;
        }
      }
    }
  }
}

void playNote() {
  byte note = noteBuffer[bufferIndex];  
  carrier_freq = mtof((int) note);
}

void setup(){
  // switch rx and tx leds of, so they don't blink on midi
  pinMode(LED_BUILTIN_TX,INPUT);
  pinMode(LED_BUILTIN_RX,INPUT);

  startMozzi();

  //MIDI DIN
  MIDI.setHandleNoteOn(noteOn);
  MIDI.setHandleNoteOff(noteOff);
  MIDI.begin(MIDI_CHANNEL);  
}

void updateControl(){
  //MIDI USB
  midiEventPacket_t rx;
  do {
    rx = MidiUSB.read();
    if (rx.header == 0x09) {
      noteOn(rx.byte1 - 143, rx.byte2, rx.byte3); //need to figure out what's with this 143 and 127 on noteoff
    } else if (rx.header == 0x08) {
      noteOff(rx.byte1 - 127, rx.byte2, rx.byte3);
    }
  } while (rx.header != 0);

  //Knob 3  
  int freqVal = mozziAnalogRead(CONTROLL3); // value is 0-1023
  int FRQ = mapThis(freqVal);

  //Knob 4
  int knob4 = mozziAnalogRead(CONTROLL4); // value is 0-1023
  int knob4calibrated = mapThis(knob4);
  
  //calculate the modulation frequency to stay in ratio
  int mod_freq = carrier_freq * mod_ratio * FRQ;
  
  // set the FM oscillator frequencies
  aCarrier.setFreq(carrier_freq); 
  aModulator.setFreq(mod_freq);

  //Knob 1
  int Knob1value= mozziAnalogRead(CONTROLL1); // value is 0-1023
  int Knob1calibrated = kMapIntensity(Knob1value);
  
  // calculate the fm_intensity
  fm_intensity = ((long)Knob1calibrated * knob4calibrated * (kIntensityMod.next()+128))>>8; // shift back to range after 8 bit multiply
  
  // Knob 2
  int Knob2value= mozziAnalogRead(CONTROLL2); // value is 0-1023
  
  // use a float here for low frequencies
  float mod_speed = (float)kMapModSpeed(Knob2value)/1000;
  kIntensityMod.setFreq(mod_speed);

  // Debugging
  Serial.print("Buffer Index: ");
  Serial.print(bufferIndex);

  Serial.print(" | Knob1: "); //3rd on the pannel, connected to A0
  Serial.print(Knob1calibrated);
  
  Serial.print(" | Knob2: "); //2nd on the pannel, conntcted to A1
  Serial.print(Knob2value);
  
  Serial.print(" | Knob3: "); //1st on the pannel, connected to A2, unstable around 0
  Serial.print(FRQ);
  
  Serial.print(" | Knob4: "); //4th on the pannel, A3
  Serial.print(knob4calibrated);
  
  Serial.println();

  // MIDI DIN
  MIDI.read();
}


AudioOutput_t updateAudio(){
  long modulation = aSmoothIntensity.next(fm_intensity) * aModulator.next();
  if (gate == 1) {
    return aCarrier.phMod(modulation);//(int)(envelope.next() * aCarrier.phMod(modulation))>>8;
  }
}

void loop(){
  audioHook();
}