/* Arduino "guitar" based on Mozzi audio library by Tim Barrass.
 *
 * Code by Andrew McPherson, Queen Mary University of London, September 2012
 *
 * http://www.eecs.qmul.ac.uk/
 *
 * Circuit: 
 *   audio output on pin 9 (to filter and LM386 amplifier)
 *   analog inputs (knobs/sliders) on pins A0-A3
 *   digital inputs (buttons) on pins 2-5
 */ 
 
#include <MozziGuts.h>
#include <Oscil.h>
#include <tables/sin2048_int8.h>
#include <tables/waveshape_chebyshev_3rd_256_int8.h>
#include <tables/waveshape_chebyshev_6th_256_int8.h>
#include <tables/waveshape_compress_512_to_488_int16.h>
#include <tables/waveshape2_softerclip_int8.h>
#include <tables/saw_analogue512_int8.h>
#include <MozziGuts.h>
#include <Oscil.h>
#include <WaveShaper.h>
#include <EventDelay.h>
#include <utils.h>
#include <Smooth.h>
#include <fixedMath.h> // for fractional modulation frequency
#include <Ead.h> // exponential attack decay

#define CONTROL_RATE 128 // powers of 2 please

// Pin definitions for analog and digital inputs:

#define PITCH_PIN A0
#define VOLUME_PIN A1
#define DECAY_PIN A2
#define TUNING_PIN A3

#define GUITAR1_PIN 2
#define GUITAR2_PIN 3
#define GUITAR3_PIN 4
#define BASS_PIN 5

// Basic pitch of the instrument (MIDI 45 = A2)
#define MIDI_NOTE_MIN (Q16n16)(33L << 16L)

Oscil <SIN2048_NUM_CELLS, AUDIO_RATE> aSinGuitar1(SIN2048_DATA); // sine wave sound source
Oscil <SIN2048_NUM_CELLS, AUDIO_RATE> aSinGuitar2(SIN2048_DATA);
Oscil <SIN2048_NUM_CELLS, AUDIO_RATE> aSinGuitar3(SIN2048_DATA);
Oscil <SAW_ANALOGUE512_NUM_CELLS, AUDIO_RATE> aSawBass(SAW_ANALOGUE512_DATA);

WaveShaper <int> aCompress(WAVESHAPE_COMPRESS_512_TO_488_DATA); // to compress instead of dividing by 2 after adding signals

WaveShaper <char> aGuitar1Shaper(WAVESHAPE2_SOFTERCLIP_DATA);
WaveShaper <char> aGuitar2Shaper(WAVESHAPE2_SOFTERCLIP_DATA);
WaveShaper <char> aGuitar3Shaper(WAVESHAPE2_SOFTERCLIP_DATA);

Ead kEnvelopeGuitar1(CONTROL_RATE);
Ead kEnvelopeGuitar2(CONTROL_RATE);
Ead kEnvelopeGuitar3(CONTROL_RATE);
Ead kEnvelopeBass(CONTROL_RATE);

/* Parameters controlled by analog inputs */
unsigned long pitch;
unsigned char volume;
unsigned int decay;
unsigned int tuning;

unsigned char lastGuitar1Val = 0, lastGuitar2Val = 0, lastGuitar3Val = 0, lastBassVal = 0;
unsigned int attackMilliseconds = 20, decayMilliseconds = 3000;
unsigned int lastDecayValue = 0;
int gainGuitar1, gainGuitar2, gainGuitar3, gainBass;

void updateAttackDecayValues() {
  kEnvelopeGuitar1.set(attackMilliseconds, decayMilliseconds);
  kEnvelopeGuitar2.set(attackMilliseconds, decayMilliseconds);
  kEnvelopeGuitar3.set(attackMilliseconds, decayMilliseconds);
  kEnvelopeBass.set(attackMilliseconds*4, decayMilliseconds*2);  
}

void setup(){
  startMozzi(CONTROL_RATE);
  
  aSinGuitar1.setFreq(110u); // set the frequency with an unsigned int or a float
  aSinGuitar2.setFreq(165u);
  aSinGuitar3.setFreq(275u);
  aSawBass.setFreq(55u);
  
  updateAttackDecayValues();
  setupFastAnalogRead();
  
  Serial.begin(57600); 
}

void updateControl() {
  static Q16n16 midiNote, midiNoteInt, baseFrequency;
  static long midiNoteFrac;
  
  /* Read sensor data and update audio parameters accordingly */
  pitch = analogRead(PITCH_PIN);  // Range: 0 to 1023
  volume = analogRead(VOLUME_PIN) >> 2;  // Range: 0 to 255
  decay = analogRead(DECAY_PIN);  // Range: 0 to 1023
  tuning = analogRead(TUNING_PIN); // Range: 0 to 1023
  
  /* Read digital sensor data (buttons) */
  unsigned char guitar1Val = digitalRead(GUITAR1_PIN);
  unsigned char guitar2Val = digitalRead(GUITAR2_PIN);
  unsigned char guitar3Val = digitalRead(GUITAR3_PIN);
  unsigned char bassVal = digitalRead(BASS_PIN);
  
  /* Only change the decay value if a significant change has occurred,
   * to filter out noise on the input. This will reduce unneeded calculations. */
  if(abs(decay - lastDecayValue) > 4) {
    decayMilliseconds = decay << 2; 
    lastDecayValue = decay; 
    updateAttackDecayValues();
  }
  
  /* Values that are high now and were low last cycle mean that
   * a button has been pushed. Start the corresponding string. */
  if(guitar1Val == HIGH && lastGuitar1Val == LOW) {
    kEnvelopeGuitar1.start();
  }
  if(guitar2Val == HIGH && lastGuitar2Val == LOW) {
    kEnvelopeGuitar2.start();
  }
  if(guitar3Val == HIGH && lastGuitar3Val == LOW) {
    kEnvelopeGuitar3.start();
  }
  if(bassVal == HIGH && lastBassVal == LOW) {
    kEnvelopeBass.start();
  }
  
  lastGuitar1Val = guitar1Val;
  lastGuitar2Val = guitar2Val;
  lastGuitar3Val = guitar3Val;
  lastBassVal = bassVal;
  
  /* pitch: 0 = minimum value; 1024 = +32 semitones (~2.5 octaves) 
   * 6 bits left to get to decimal point + 5 bits more = 11 bit shift */
  
  midiNote = MIDI_NOTE_MIN + (Q16n16)(pitch << 11);
  
  /* Set the amount the pitch is quantized. */
  midiNoteInt = (midiNote + 0x00008000) & 0xFFFF0000; // Nearest MIDI note (Q16n16 rounding)
  midiNoteFrac = (long)midiNote - (long)midiNoteInt; /* Fractional part only */
  midiNoteFrac = (midiNoteFrac * (1023 - tuning)) >> 10; /* Scale the fractional part */
  midiNote = midiNoteInt + midiNoteFrac;
  
  baseFrequency = Q16n16_mtof(midiNote);
  
  aSinGuitar1.setFreq_Q16n16(baseFrequency * 3);
  aSinGuitar2.setFreq_Q16n16(baseFrequency << 2);
  aSinGuitar3.setFreq_Q16n16(baseFrequency * 5);
  aSawBass.setFreq_Q16n16(baseFrequency); // down 1 octave
  
  gainGuitar1 = kEnvelopeGuitar1.next();
  gainGuitar2 = kEnvelopeGuitar2.next();
  gainGuitar3 = kEnvelopeGuitar3.next();
  gainBass = kEnvelopeBass.next();
  
  if(gainGuitar1 > 96) gainGuitar1 = 96;
  if(gainGuitar2 > 96) gainGuitar2 = 96;
  if(gainGuitar3 > 96) gainGuitar3 = 96;
}


int updateAudio(){
  char aGuitar1 = aSinGuitar1.next(); // sine wave source
  char aGuitar2 = aSinGuitar2.next(); // sine wave source
  char aGuitar3 = aSinGuitar3.next(); // sine wave source
  char aBass = aSawBass.next(); // sawtooth wave source
  
  int aGuitar1Shaped = aGuitar1Shaper.next(aGuitar1);
  int aGuitar2Shaped = aGuitar2Shaper.next(aGuitar2);
  int aGuitar3Shaped = aGuitar3Shaper.next(aGuitar3);

  long waveSum = (gainGuitar1*aGuitar1Shaped + gainGuitar2*aGuitar2Shaped + gainGuitar3*aGuitar3Shaped + gainBass*aBass) >> 8;
  waveSum = (waveSum * volume) >> 8;

  // use a waveshaping table to squeeze 2 summed 8 bit signals into the range -244 to 243
  int waveshapedOut = aCompress.next(256u + waveSum);
  
  return waveshapedOut;
}


void loop(){
  audioHook();
}