qmk_firmware/quantum/audio/audio_arm.c

/* Copyright 2016 Jack Humbert
 *
 * This program is free software: you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation, either version 2 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program.  If not, see <http://www.gnu.org/licenses/>.
 */

#include "audio.h"
#include "ch.h"
#include "hal.h"

#include <string.h>
#include "print.h"
#include "keymap.h"

#include "eeconfig.h"

// -----------------------------------------------------------------------------

int voices = 0;
int voice_place = 0;
float frequency = 0;
float frequency_alt = 0;
int volume = 0;
long position = 0;

float frequencies[8] = {0, 0, 0, 0, 0, 0, 0, 0};
int volumes[8] = {0, 0, 0, 0, 0, 0, 0, 0};
bool sliding = false;

float place = 0;

uint8_t * sample;
uint16_t sample_length = 0;

bool     playing_notes = false;
bool     playing_note = false;
float    note_frequency = 0;
float    note_length = 0;
uint8_t  note_tempo = TEMPO_DEFAULT;
float    note_timbre = TIMBRE_DEFAULT;
uint16_t note_position = 0;
float (* notes_pointer)[][2];
uint16_t notes_count;
bool     notes_repeat;
bool     note_resting = false;

uint16_t current_note = 0;
uint8_t rest_counter = 0;

#ifdef VIBRATO_ENABLE
float vibrato_counter = 0;
float vibrato_strength = .5;
float vibrato_rate = 0.125;
#endif

float polyphony_rate = 0;

static bool audio_initialized = false;

audio_config_t audio_config;

uint16_t envelope_index = 0;
bool glissando = true;

#ifndef STARTUP_SONG
    #define STARTUP_SONG SONG(STARTUP_SOUND)
#endif
float startup_song[][2] = STARTUP_SONG;

static void gpt_cb8(GPTDriver *gptp);

#define DAC_BUFFER_SIZE 720
#ifndef DAC_SAMPLE_MAX
#define DAC_SAMPLE_MAX  65535U
#endif

#define START_CHANNEL_1() gptStart(&GPTD6, &gpt6cfg1); \
    gptStartContinuous(&GPTD6, 2U)
#define START_CHANNEL_2() gptStart(&GPTD7, &gpt7cfg1); \
    gptStartContinuous(&GPTD7, 2U)
#define STOP_CHANNEL_1() gptStopTimer(&GPTD6)
#define STOP_CHANNEL_2() gptStopTimer(&GPTD7)
#define RESTART_CHANNEL_1() STOP_CHANNEL_1(); \
    START_CHANNEL_1()
#define RESTART_CHANNEL_2() STOP_CHANNEL_2(); \
    START_CHANNEL_2()
#define UPDATE_CHANNEL_1_FREQ(freq) gpt6cfg1.frequency = freq * DAC_BUFFER_SIZE; \
    RESTART_CHANNEL_1()
#define UPDATE_CHANNEL_2_FREQ(freq) gpt7cfg1.frequency = freq * DAC_BUFFER_SIZE; \
    RESTART_CHANNEL_2()
#define GET_CHANNEL_1_FREQ gpt6cfg1.frequency
#define GET_CHANNEL_2_FREQ gpt7cfg1.frequency


/*
 * GPT6 configuration.
 */
// static const GPTConfig gpt6cfg1 = {
//   .frequency    = 1000000U,
//   .callback     = NULL,
//   .cr2          = TIM_CR2_MMS_1,    /* MMS = 010 = TRGO on Update Event.    */
//   .dier         = 0U
// };

GPTConfig gpt6cfg1 = {
  .frequency    = 440U*DAC_BUFFER_SIZE,
  .callback     = NULL,
  .cr2          = TIM_CR2_MMS_1,    /* MMS = 010 = TRGO on Update Event.    */
  .dier         = 0U
};

GPTConfig gpt7cfg1 = {
  .frequency    = 440U*DAC_BUFFER_SIZE,
  .callback     = NULL,
  .cr2          = TIM_CR2_MMS_1,    /* MMS = 010 = TRGO on Update Event.    */
  .dier         = 0U
};

GPTConfig gpt8cfg1 = {
  .frequency    = 10,
  .callback     = gpt_cb8,
  .cr2          = TIM_CR2_MMS_1,    /* MMS = 010 = TRGO on Update Event.    */
  .dier         = 0U
};


/*
 * DAC test buffer (sine wave).
 */
// static const dacsample_t dac_buffer[DAC_BUFFER_SIZE] = {
//   2047, 2082, 2118, 2154, 2189, 2225, 2260, 2296, 2331, 2367, 2402, 2437,
//   2472, 2507, 2542, 2576, 2611, 2645, 2679, 2713, 2747, 2780, 2813, 2846,
//   2879, 2912, 2944, 2976, 3008, 3039, 3070, 3101, 3131, 3161, 3191, 3221,
//   3250, 3278, 3307, 3335, 3362, 3389, 3416, 3443, 3468, 3494, 3519, 3544,
//   3568, 3591, 3615, 3637, 3660, 3681, 3703, 3723, 3744, 3763, 3782, 3801,
//   3819, 3837, 3854, 3870, 3886, 3902, 3917, 3931, 3944, 3958, 3970, 3982,
//   3993, 4004, 4014, 4024, 4033, 4041, 4049, 4056, 4062, 4068, 4074, 4078,
//   4082, 4086, 4089, 4091, 4092, 4093, 4094, 4093, 4092, 4091, 4089, 4086,
//   4082, 4078, 4074, 4068, 4062, 4056, 4049, 4041, 4033, 4024, 4014, 4004,
//   3993, 3982, 3970, 3958, 3944, 3931, 3917, 3902, 3886, 3870, 3854, 3837,
//   3819, 3801, 3782, 3763, 3744, 3723, 3703, 3681, 3660, 3637, 3615, 3591,
//   3568, 3544, 3519, 3494, 3468, 3443, 3416, 3389, 3362, 3335, 3307, 3278,
//   3250, 3221, 3191, 3161, 3131, 3101, 3070, 3039, 3008, 2976, 2944, 2912,
//   2879, 2846, 2813, 2780, 2747, 2713, 2679, 2645, 2611, 2576, 2542, 2507,
//   2472, 2437, 2402, 2367, 2331, 2296, 2260, 2225, 2189, 2154, 2118, 2082,
//   2047, 2012, 1976, 1940, 1905, 1869, 1834, 1798, 1763, 1727, 1692, 1657,
//   1622, 1587, 1552, 1518, 1483, 1449, 1415, 1381, 1347, 1314, 1281, 1248,
//   1215, 1182, 1150, 1118, 1086, 1055, 1024,  993,  963,  933,  903,  873,
//    844,  816,  787,  759,  732,  705,  678,  651,  626,  600,  575,  550,
//    526,  503,  479,  457,  434,  413,  391,  371,  350,  331,  312,  293,
//    275,  257,  240,  224,  208,  192,  177,  163,  150,  136,  124,  112,
//    101,   90,   80,   70,   61,   53,   45,   38,   32,   26,   20,   16,
//     12,    8,    5,    3,    2,    1,    0,    1,    2,    3,    5,    8,
//     12,   16,   20,   26,   32,   38,   45,   53,   61,   70,   80,   90,
//    101,  112,  124,  136,  150,  163,  177,  192,  208,  224,  240,  257,
//    275,  293,  312,  331,  350,  371,  391,  413,  434,  457,  479,  503,
//    526,  550,  575,  600,  626,  651,  678,  705,  732,  759,  787,  816,
//    844,  873,  903,  933,  963,  993, 1024, 1055, 1086, 1118, 1150, 1182,
//   1215, 1248, 1281, 1314, 1347, 1381, 1415, 1449, 1483, 1518, 1552, 1587,
//   1622, 1657, 1692, 1727, 1763, 1798, 1834, 1869, 1905, 1940, 1976, 2012
// };

// static const dacsample_t dac_buffer_2[DAC_BUFFER_SIZE] = {
//     12,    8,    5,    3,    2,    1,    0,    1,    2,    3,    5,    8,
//     12,   16,   20,   26,   32,   38,   45,   53,   61,   70,   80,   90,
//    101,  112,  124,  136,  150,  163,  177,  192,  208,  224,  240,  257,
//    275,  293,  312,  331,  350,  371,  391,  413,  434,  457,  479,  503,
//    526,  550,  575,  600,  626,  651,  678,  705,  732,  759,  787,  816,
//    844,  873,  903,  933,  963,  993, 1024, 1055, 1086, 1118, 1150, 1182,
//   1215, 1248, 1281, 1314, 1347, 1381, 1415, 1449, 1483, 1518, 1552, 1587,
//   1622, 1657, 1692, 1727, 1763, 1798, 1834, 1869, 1905, 1940, 1976, 2012,
//   2047, 2082, 2118, 2154, 2189, 2225, 2260, 2296, 2331, 2367, 2402, 2437,
//   2472, 2507, 2542, 2576, 2611, 2645, 2679, 2713, 2747, 2780, 2813, 2846,
//   2879, 2912, 2944, 2976, 3008, 3039, 3070, 3101, 3131, 3161, 3191, 3221,
//   3250, 3278, 3307, 3335, 3362, 3389, 3416, 3443, 3468, 3494, 3519, 3544,
//   3568, 3591, 3615, 3637, 3660, 3681, 3703, 3723, 3744, 3763, 3782, 3801,
//   3819, 3837, 3854, 3870, 3886, 3902, 3917, 3931, 3944, 3958, 3970, 3982,
//   3993, 4004, 4014, 4024, 4033, 4041, 4049, 4056, 4062, 4068, 4074, 4078,
//   4082, 4086, 4089, 4091, 4092, 4093, 4094, 4093, 4092, 4091, 4089, 4086,
//   4082, 4078, 4074, 4068, 4062, 4056, 4049, 4041, 4033, 4024, 4014, 4004,
//   3993, 3982, 3970, 3958, 3944, 3931, 3917, 3902, 3886, 3870, 3854, 3837,
//   3819, 3801, 3782, 3763, 3744, 3723, 3703, 3681, 3660, 3637, 3615, 3591,
//   3568, 3544, 3519, 3494, 3468, 3443, 3416, 3389, 3362, 3335, 3307, 3278,
//   3250, 3221, 3191, 3161, 3131, 3101, 3070, 3039, 3008, 2976, 2944, 2912,
//   2879, 2846, 2813, 2780, 2747, 2713, 2679, 2645, 2611, 2576, 2542, 2507,
//   2472, 2437, 2402, 2367, 2331, 2296, 2260, 2225, 2189, 2154, 2118, 2082,
//   2047, 2012, 1976, 1940, 1905, 1869, 1834, 1798, 1763, 1727, 1692, 1657,
//   1622, 1587, 1552, 1518, 1483, 1449, 1415, 1381, 1347, 1314, 1281, 1248,
//   1215, 1182, 1150, 1118, 1086, 1055, 1024,  993,  963,  933,  903,  873,
//    844,  816,  787,  759,  732,  705,  678,  651,  626,  600,  575,  550,
//    526,  503,  479,  457,  434,  413,  391,  371,  350,  331,  312,  293,
//    275,  257,  240,  224,  208,  192,  177,  163,  150,  136,  124,  112,
//    101,   90,   80,   70,   61,   53,   45,   38,   32,   26,   20,   16
// };

// squarewave
static const dacsample_t dac_buffer[DAC_BUFFER_SIZE] = {
  // First half is max, second half is 0
  [0                 ... DAC_BUFFER_SIZE/2-1] = DAC_SAMPLE_MAX,
  [DAC_BUFFER_SIZE/2 ... DAC_BUFFER_SIZE  -1] = 0,
};

// squarewave
static const dacsample_t dac_buffer_2[DAC_BUFFER_SIZE] = {
  // opposite of dac_buffer above
  [0                 ... DAC_BUFFER_SIZE/2-1] = 0,
  [DAC_BUFFER_SIZE/2 ... DAC_BUFFER_SIZE  -1] = DAC_SAMPLE_MAX,
};

/*
 * DAC streaming callback.
 */
size_t nx = 0, ny = 0, nz = 0;
static void end_cb1(DACDriver *dacp, dacsample_t *buffer, size_t n) {

  (void)dacp;

  nz++;
  if (dac_buffer == buffer) {
    nx += n;
  }
  else {
    ny += n;
  }

  if ((nz % 1000) == 0) {
    // palTogglePad(GPIOD, GPIOD_LED3);
  }
}

/*
 * DAC error callback.
 */
static void error_cb1(DACDriver *dacp, dacerror_t err) {

  (void)dacp;
  (void)err;

  chSysHalt("DAC failure");
}

static const DACConfig dac1cfg1 = {
  .init         = DAC_SAMPLE_MAX,
  .datamode     = DAC_DHRM_12BIT_RIGHT
};

static const DACConversionGroup dacgrpcfg1 = {
  .num_channels = 1U,
  .end_cb       = end_cb1,
  .error_cb     = error_cb1,
  .trigger      = DAC_TRG(0)
};

static const DACConfig dac1cfg2 = {
  .init         = DAC_SAMPLE_MAX,
  .datamode     = DAC_DHRM_12BIT_RIGHT
};

static const DACConversionGroup dacgrpcfg2 = {
  .num_channels = 1U,
  .end_cb       = end_cb1,
  .error_cb     = error_cb1,
  .trigger      = DAC_TRG(0)
};

void audio_init() {

  if (audio_initialized) {
    return;
  }

  // Check EEPROM
  #if defined(STM32_EEPROM_ENABLE) || defined(PROTOCOL_ARM_ATSAM) || defined(EEPROM_SIZE)
    if (!eeconfig_is_enabled()) {
      eeconfig_init();
    }
    audio_config.raw = eeconfig_read_audio();
#else // ARM EEPROM
    audio_config.enable = true;
  #ifdef AUDIO_CLICKY_ON
    audio_config.clicky_enable = true;
  #endif
#endif // ARM EEPROM

  /*
   * Starting DAC1 driver, setting up the output pin as analog as suggested
   * by the Reference Manual.
   */
  palSetPadMode(GPIOA, 4, PAL_MODE_INPUT_ANALOG);
  palSetPadMode(GPIOA, 5, PAL_MODE_INPUT_ANALOG);
  dacStart(&DACD1, &dac1cfg1);
  dacStart(&DACD2, &dac1cfg2);

  /*
   * Starting GPT6/7 driver, it is used for triggering the DAC.
   */
  START_CHANNEL_1();
  START_CHANNEL_2();

  /*
   * Starting a continuous conversion.
   */
  dacStartConversion(&DACD1, &dacgrpcfg1, (dacsample_t *)dac_buffer, DAC_BUFFER_SIZE);
  dacStartConversion(&DACD2, &dacgrpcfg2, (dacsample_t *)dac_buffer_2, DAC_BUFFER_SIZE);

  audio_initialized = true;

  if (audio_config.enable) {
    PLAY_SONG(startup_song);
  } else {
    stop_all_notes();
  }

}

void stop_all_notes() {
    dprintf("audio stop all notes");

    if (!audio_initialized) {
        audio_init();
    }
    voices = 0;

    gptStopTimer(&GPTD6);
    gptStopTimer(&GPTD7);
    gptStopTimer(&GPTD8);

    playing_notes = false;
    playing_note = false;
    frequency = 0;
    frequency_alt = 0;
    volume = 0;

    for (uint8_t i = 0; i < 8; i++)
    {
        frequencies[i] = 0;
        volumes[i] = 0;
    }
}

void stop_note(float freq) {
  dprintf("audio stop note freq=%d", (int)freq);

  if (playing_note) {
    if (!audio_initialized) {
      audio_init();
    }
    for (int i = 7; i >= 0; i--) {
      if (frequencies[i] == freq) {
        frequencies[i] = 0;
        volumes[i] = 0;
        for (int j = i; (j < 7); j++) {
          frequencies[j] = frequencies[j+1];
          frequencies[j+1] = 0;
          volumes[j] = volumes[j+1];
          volumes[j+1] = 0;
        }
        break;
      }
    }
    voices--;
    if (voices < 0) {
      voices = 0;
    }
    if (voice_place >= voices) {
      voice_place = 0;
    }
    if (voices == 0) {
      STOP_CHANNEL_1();
      STOP_CHANNEL_2();
      gptStopTimer(&GPTD8);
      frequency = 0;
      frequency_alt = 0;
      volume = 0;
      playing_note = false;
    }
  }
}

#ifdef VIBRATO_ENABLE

float mod(float a, int b) {
  float r = fmod(a, b);
  return r < 0 ? r + b : r;
}

float vibrato(float average_freq) {
  #ifdef VIBRATO_STRENGTH_ENABLE
    float vibrated_freq = average_freq * pow(vibrato_lut[(int)vibrato_counter], vibrato_strength);
  #else
    float vibrated_freq = average_freq * vibrato_lut[(int)vibrato_counter];
  #endif
  vibrato_counter = mod((vibrato_counter + vibrato_rate * (1.0 + 440.0/average_freq)), VIBRATO_LUT_LENGTH);
  return vibrated_freq;
}

#endif

static void gpt_cb8(GPTDriver *gptp) {
  float freq;

  if (playing_note) {
    if (voices > 0) {

      float freq_alt = 0;
      if (voices > 1) {
        if (polyphony_rate == 0) {
          if (glissando) {
            if (frequency_alt != 0 && frequency_alt < frequencies[voices - 2] && frequency_alt < frequencies[voices - 2] * pow(2, -440/frequencies[voices - 2]/12/2)) {
              frequency_alt = frequency_alt * pow(2, 440/frequency_alt/12/2);
            } else if (frequency_alt != 0 && frequency_alt > frequencies[voices - 2] && frequency_alt > frequencies[voices - 2] * pow(2, 440/frequencies[voices - 2]/12/2)) {
              frequency_alt = frequency_alt * pow(2, -440/frequency_alt/12/2);
            } else {
              frequency_alt = frequencies[voices - 2];
            }
          } else {
            frequency_alt = frequencies[voices - 2];
          }

          #ifdef VIBRATO_ENABLE
            if (vibrato_strength > 0) {
              freq_alt = vibrato(frequency_alt);
            } else {
              freq_alt = frequency_alt;
            }
          #else
            freq_alt = frequency_alt;
          #endif
        }

        if (envelope_index < 65535) {
          envelope_index++;
        }

        freq_alt = voice_envelope(freq_alt);

        if (freq_alt < 30.517578125) {
          freq_alt = 30.52;
        }

        if (GET_CHANNEL_2_FREQ != (uint16_t)freq_alt) {
          UPDATE_CHANNEL_2_FREQ(freq_alt);
        } else {
          RESTART_CHANNEL_2();
        }
        //note_timbre;
      }

      if (polyphony_rate > 0) {
        if (voices > 1) {
          voice_place %= voices;
          if (place++ > (frequencies[voice_place] / polyphony_rate)) {
            voice_place = (voice_place + 1) % voices;
            place = 0.0;
          }
        }

        #ifdef VIBRATO_ENABLE
          if (vibrato_strength > 0) {
              freq = vibrato(frequencies[voice_place]);
          } else {
              freq = frequencies[voice_place];
          }
        #else
          freq = frequencies[voice_place];
        #endif
      } else {
        if (glissando) {
          if (frequency != 0 && frequency < frequencies[voices - 1] && frequency < frequencies[voices - 1] * pow(2, -440/frequencies[voices - 1]/12/2)) {
            frequency = frequency * pow(2, 440/frequency/12/2);
          } else if (frequency != 0 && frequency > frequencies[voices - 1] && frequency > frequencies[voices - 1] * pow(2, 440/frequencies[voices - 1]/12/2)) {
            frequency = frequency * pow(2, -440/frequency/12/2);
          } else {
            frequency = frequencies[voices - 1];
          }
        } else {
          frequency = frequencies[voices - 1];
        }

        #ifdef VIBRATO_ENABLE
          if (vibrato_strength > 0) {
            freq = vibrato(frequency);
          } else {
            freq = frequency;
          }
        #else
          freq = frequency;
        #endif
      }

      if (envelope_index < 65535) {
        envelope_index++;
      }

      freq = voice_envelope(freq);

      if (freq < 30.517578125) {
        freq = 30.52;
      }


      if (GET_CHANNEL_1_FREQ != (uint16_t)freq) {
        UPDATE_CHANNEL_1_FREQ(freq);
      } else {
        RESTART_CHANNEL_1();
      }
      //note_timbre;
    }
  }

  if (playing_notes) {
    if (note_frequency > 0) {
      #ifdef VIBRATO_ENABLE
        if (vibrato_strength > 0) {
          freq = vibrato(note_frequency);
        } else {
          freq = note_frequency;
        }
      #else
        freq = note_frequency;
      #endif

      if (envelope_index < 65535) {
        envelope_index++;
      }
      freq = voice_envelope(freq);


      if (GET_CHANNEL_1_FREQ != (uint16_t)freq) {
        UPDATE_CHANNEL_1_FREQ(freq);
        UPDATE_CHANNEL_2_FREQ(freq);
      }
      //note_timbre;
    } else {
        // gptStopTimer(&GPTD6);
        // gptStopTimer(&GPTD7);
    }

    note_position++;
    bool end_of_note = false;
    if (GET_CHANNEL_1_FREQ > 0) {
      if (!note_resting)
        end_of_note = (note_position >= (note_length*8 - 1));
      else
        end_of_note = (note_position >= (note_length*8));
    } else {
      end_of_note = (note_position >= (note_length*8));
    }

    if (end_of_note) {
      current_note++;
      if (current_note >= notes_count) {
        if (notes_repeat) {
          current_note = 0;
        } else {
          STOP_CHANNEL_1();
          STOP_CHANNEL_2();
          // gptStopTimer(&GPTD8);
          playing_notes = false;
          return;
        }
      }
      if (!note_resting) {
        note_resting = true;
        current_note--;
        if ((*notes_pointer)[current_note][0] == (*notes_pointer)[current_note + 1][0]) {
          note_frequency = 0;
          note_length = 1;
        } else {
          note_frequency = (*notes_pointer)[current_note][0];
          note_length = 1;
        }
      } else {
        note_resting = false;
        envelope_index = 0;
        note_frequency = (*notes_pointer)[current_note][0];
        note_length = ((*notes_pointer)[current_note][1] / 4) * (((float)note_tempo) / 100);
      }

      note_position = 0;
    }
  }

  if (!audio_config.enable) {
    playing_notes = false;
    playing_note = false;
  }
}

void play_note(float freq, int vol) {

  dprintf("audio play note freq=%d vol=%d", (int)freq, vol);

  if (!audio_initialized) {
      audio_init();
  }

  if (audio_config.enable && voices < 8) {

     // Cancel notes if notes are playing
    if (playing_notes) {
      stop_all_notes();
    }

    playing_note = true;

    envelope_index = 0;

    if (freq > 0) {
      frequencies[voices] = freq;
      volumes[voices] = vol;
      voices++;
    }

    gptStart(&GPTD8, &gpt8cfg1);
    gptStartContinuous(&GPTD8, 2U);
    RESTART_CHANNEL_1();
    RESTART_CHANNEL_2();
  }

}

void play_notes(float (*np)[][2], uint16_t n_count, bool n_repeat) {

  if (!audio_initialized) {
    audio_init();
  }

  if (audio_config.enable) {

    // Cancel note if a note is playing
    if (playing_note) {
      stop_all_notes();
    }

    playing_notes = true;

    notes_pointer = np;
    notes_count = n_count;
    notes_repeat = n_repeat;

    place = 0;
    current_note = 0;

    note_frequency = (*notes_pointer)[current_note][0];
    note_length = ((*notes_pointer)[current_note][1] / 4) * (((float)note_tempo) / 100);
    note_position = 0;

    gptStart(&GPTD8, &gpt8cfg1);
    gptStartContinuous(&GPTD8, 2U);
    RESTART_CHANNEL_1();
    RESTART_CHANNEL_2();
  }
}

bool is_playing_notes(void) {
  return playing_notes;
}

bool is_audio_on(void) {
  return (audio_config.enable != 0);
}

void audio_toggle(void) {
  audio_config.enable ^= 1;
  eeconfig_update_audio(audio_config.raw);
  if (audio_config.enable) {
    audio_on_user();
  }
}

void audio_on(void) {
  audio_config.enable = 1;
  eeconfig_update_audio(audio_config.raw);
  audio_on_user();
}

void audio_off(void) {
  stop_all_notes();
  audio_config.enable = 0;
  eeconfig_update_audio(audio_config.raw);
}

#ifdef VIBRATO_ENABLE

// Vibrato rate functions

void set_vibrato_rate(float rate) {
  vibrato_rate = rate;
}

void increase_vibrato_rate(float change) {
  vibrato_rate *= change;
}

void decrease_vibrato_rate(float change) {
  vibrato_rate /= change;
}

#ifdef VIBRATO_STRENGTH_ENABLE

void set_vibrato_strength(float strength) {
  vibrato_strength = strength;
}

void increase_vibrato_strength(float change) {
  vibrato_strength *= change;
}

void decrease_vibrato_strength(float change) {
  vibrato_strength /= change;
}

#endif  /* VIBRATO_STRENGTH_ENABLE */

#endif /* VIBRATO_ENABLE */

// Polyphony functions

void set_polyphony_rate(float rate) {
  polyphony_rate = rate;
}

void enable_polyphony() {
  polyphony_rate = 5;
}

void disable_polyphony() {
  polyphony_rate = 0;
}

void increase_polyphony_rate(float change) {
  polyphony_rate *= change;
}

void decrease_polyphony_rate(float change) {
  polyphony_rate /= change;
}

// Timbre function

void set_timbre(float timbre) {
  note_timbre = timbre;
}

// Tempo functions

void set_tempo(uint8_t tempo) {
  note_tempo = tempo;
}

void decrease_tempo(uint8_t tempo_change) {
  note_tempo += tempo_change;
}

void increase_tempo(uint8_t tempo_change) {
  if (note_tempo - tempo_change < 10) {
    note_tempo = 10;
  } else {
    note_tempo -= tempo_change;
  }
}