uilleann/synth.ino

#include <Audio.h>
#include <Wire.h>
#include <Adafruit_NeoTrellisM4.h>
#include <SFE_MicroOLED.h>
#include <Adafruit_MPR121.h>
#include "synth.h"
#include "patches.h"
#include "notes.h"
#include "fingering.h"

#define KNEE_OFFSET 0
#define KEY_OFFSET 2

float cmaj_low[8] = { 130.81, 146.83, 164.81, 174.61, 196.00, 220.00, 246.94, 261.63 };
float cmaj_high[8] = { 261.6, 293.7, 329.6, 349.2, 392.0, 440.0, 493.9, 523.3 };

AudioEffectEnvelope *envs[] = {&env1, &env2, &env3, &env4};
AudioSynthWaveformSineModulated *oscs[] = {&osc1, &osc2, &osc3, &osc4};

int currentPatch = 0;

Adafruit_MPR121 cap = Adafruit_MPR121();
Adafruit_NeoTrellisM4 trellis = Adafruit_NeoTrellisM4();
MicroOLED oled(9, 1);

// Hat tip to Kyle Gann
// https://www.kylegann.com/tuning.html
float JustPitches[MaxNote + 1];
void setupJustPitches(uint8_t baseNote, float basePitch) {
  JustPitches[baseNote +  0] = basePitch *  1 /  1;
  JustPitches[baseNote +  1] = basePitch * 16 / 15;
  JustPitches[baseNote +  2] = basePitch *  9 /  8;
  JustPitches[baseNote +  3] = basePitch *  6 /  5;
  JustPitches[baseNote +  4] = basePitch *  5 /  4;
  JustPitches[baseNote +  5] = basePitch *  4 /  3;
  JustPitches[baseNote +  6] = basePitch * 45 / 32;
  JustPitches[baseNote +  7] = basePitch *  3 /  2;
  JustPitches[baseNote +  8] = basePitch *  8 /  5;
  JustPitches[baseNote +  9] = basePitch *  5 /  3;
  JustPitches[baseNote + 10] = basePitch *  9 /  5;
  JustPitches[baseNote + 11] = basePitch * 15 /  8;

  // Octaves
  for (int note = baseNote; note < baseNote + 12; note++) {
    for (int i = 1; i < 9; i++) {
      int multiplier = 1<<i;
      int shift = i*12;
      int upNote = note + shift;
      int dnNote = note - shift;
      
      if (upNote <= MaxNote) {
        JustPitches[upNote] = JustPitches[note] * multiplier;
      }
      if (dnNote >= 0) {
        JustPitches[dnNote] = JustPitches[note] / multiplier;
      }
    }
  }
}

void loadPatch(Patch p) {
  for (int i=0; i<4; i++) {
    Operator op = p.operators[i];

    oscs[i]->amplitude(op.gain);
    envs[i]->delay(op.delay);
    envs[i]->attack(op.attack);
    envs[i]->hold(op.hold);
    envs[i]->decay(op.decay);
    envs[i]->sustain(op.sustain);
    envs[i]->release(op.release);
  }
  feedback.gain(0, p.feedback);
}

void setup(){
  setupJustPitches(NOTE_D4, PITCH_D4);
  pinMode(LED_BUILTIN, OUTPUT);

  // Wire.begin needs a moment
  delay(100);
  Wire.begin();

  // Initialize OLED display
  oled.begin();
  oled.clear(ALL);

  // Initialize the Trellis
  trellis.begin();

  // Initialize touch sensor
  bool blink = true;
  while (!cap.begin(0x5A)) {
    oled.clear(PAGE);
    oled.setCursor(0, 0);
    oled.print("No Pipe?");
    oled.display();

    trellis.setPixelColor(0, blink?0xff6666:0);
    blink = !blink;
    delay(200);
  }

  // Set aside some memory for the audio library  
  AudioMemory(120);

  // initialize tunables
  updateTunables(3, 0);

  // Initialize processor and memory measurements
  AudioProcessorUsageMaxReset();
  AudioMemoryUsageMaxReset();
}

void setPitch(float freq) {
  for (int i=0; i<4; i++) {
    Operator op = Bank[currentPatch].operators[i];
    oscs[i]->frequency(op.baseFrequency + freq*op.multiplier);
  }
}

void noteOn(float freq) {
  AudioNoInterrupts();
  for (int i=0; i<4; i++) {
    Operator op = Bank[currentPatch].operators[i];
    oscs[i]->frequency(op.baseFrequency + freq*op.multiplier);
    envs[i]->noteOn();
  }
  AudioInterrupts();
}

void noteOff() {
  AudioNoInterrupts();
  for (int i=0; i<4; i++) {
    envs[i]->noteOff();
  }
  AudioInterrupts();
}

#define BUTTON_UP 0
#define BUTTON_DOWN 8
#define BUTTON_PITCH 24
#define BUTTON_VOLUME 25

#define INIT_PITCH_ADJUST 0
#define INIT_GAIN 0.1
#define INIT_PATCH 0

int16_t pitchAdjust;
float gain;
int patch;

void updateTunables(uint8_t buttons, int note) {
  // Pitch adjust if playing A
  if (!note || (note == NOTE_A4)) {
    switch (buttons) {
    case 3:
      pitchAdjust = INIT_PITCH_ADJUST;
      break;
    case 2:
      pitchAdjust += 4;
      break;
    case 1:
      pitchAdjust -= 4;
      break;
    }
  }

  float adj = pow(2, pitchAdjust / 32768.0);
  setupJustPitches(NOTE_D4, PITCH_D4*adj);
  trellis.setPixelColor(BUTTON_PITCH, trellis.ColorHSV(uint16_t(pitchAdjust), 255, 80));

  if (!note || (note == NOTE_G4)) {
    // Volume adjust if playing G
    switch (buttons) {
    case 3:
      gain = INIT_GAIN;
      break;
    case 2:
      gain = min(gain+0.005, 1.0);
      break;
    case 1:
      gain = max(gain-0.005, 0.0);
      break;
    }
  }

  mixL.gain(0, gain);
  mixR.gain(0, gain);
  trellis.setPixelColor(BUTTON_VOLUME, trellis.ColorHSV(uint16_t(gain * 65535), 255, 80));

  if (!note || (note == NOTE_CS5)) {
    if (buttons == 3) {
      patch = INIT_PATCH;
    } else if (trellis.justPressed(BUTTON_DOWN)) {
      patch -= 1;
    } else if (trellis.justPressed(BUTTON_UP)) {
      patch += 1;
    }

    // wrap
    int bankSize = sizeof(Bank) / sizeof(Bank[0]);
    patch = (patch + bankSize) % bankSize;

    Patch p = Bank[patch];
    loadPatch(p);

    oled.clear(PAGE);
    oled.setFontType(0);
    oled.setCursor(0, 0);
    oled.print(p.name);
    oled.setCursor(0, 10);
    oled.print("Patch ");
    oled.print(patch);
    oled.display();
  }
}

const uint8_t CLOSEDVAL = 0x30;
const uint8_t OPENVAL = 0x70;
const uint8_t GLISSANDO_STEPS = OPENVAL - CLOSEDVAL;

bool playing = false;

void loop() {
  uint8_t keys = 0;
  uint8_t note;
  uint8_t glissandoKeys = 0;
  uint8_t glissandoNote;
  float glissandoOpenness = 0;
  bool bag = false;
  bool silent = false;
  bool knee = cap.filteredData(KNEE_OFFSET) < CLOSEDVAL;
  uint8_t buttons = trellis.isPressed(BUTTON_DOWN)?1:0 | trellis.isPressed(BUTTON_UP)?2:0;

  trellis.tick();

  for (int i = 0; i < 8; i++) {
    uint16_t val = max(cap.filteredData(i+KEY_OFFSET), CLOSEDVAL);
    float openness = ((val - CLOSEDVAL) / float(GLISSANDO_STEPS));

    // keys = all keys which are at least touched
    // glissandoKeys = all keys which are fully closed
    // The glissando operation computes the difference.
    if (openness < 1.0) {
      glissandoOpenness = max(glissandoOpenness, openness);
      bitSet(keys, i);

      if (openness == 0.0) {
        bitSet(glissandoKeys, i);
      }
    }
    
    // print key states
    //trellis.setPixelColor(7 - i, trellis.ColorHSV(65536/12, 255, 120*openness));
    trellis.setPixelColor(7 - i, trellis.ColorHSV(22222*openness, 255, 40));
  }
  
  note = uilleann_matrix[keys];
  glissandoNote = uilleann_matrix[glissandoKeys];

  bool alt = note & 0x80;
  bool galt = glissandoNote & 0x80;
  note = note & 0x7f;
  glissandoNote = glissandoNote & 0x7f;

  // All keys closed + knee = no sound
  if (knee) {
    if (keys == 0xff) {
      silent = true;
    }
  }

  // Jump octave if the bag is squished
  //bag = !digitalRead(BAG);
  if (bag) {
    if (keys & bit(7)) {
      note += 12;
      glissandoNote += 12;
    }
  }

  // Read some trellis button states
  if (buttons) {
    updateTunables(buttons, note);
  }

  if (silent) {
    noteOff();
    playing = false;
  } else {
    // Calculate pitch, and glissando pitch
    uint16_t pitch = JustPitches[note];
    uint16_t glissandoPitch = JustPitches[glissandoNote];

    if (alt) {
      biquad1.setLowShelf(0, 2000, 0.2, 1);
    } else {
      biquad1.setHighShelf(0, 1000, 1.0, 1);
    }
  
    // Bend pitch if fewer than 3 half steps away
    if (abs(glissandoNote - note) < 3) {
      float diff = glissandoPitch - pitch;
      pitch += diff * glissandoOpenness;
    }

    if (playing) {
      setPitch(pitch);
    } else {
      noteOn(pitch);
    }
    playing = true;
  }
}