qmk_firmware_custom/quantum/audio/muse.c

enum {
  MUSE_OFF,
  MUSE_ON,
  MUSE_C_1_2,
  MUSE_C1,
  MUSE_C2,
  MUSE_C4,
  MUSE_C8,
  MUSE_C3,
  MUSE_C6,
  MUSE_B1,
  MUSE_B2,
  MUSE_B3,
  MUSE_B4,
  MUSE_B5,
  MUSE_B6,
  MUSE_B7,
  MUSE_B8,
  MUSE_B9,
  MUSE_B10,
  MUSE_B11,
  MUSE_B12,
  MUSE_B13,
  MUSE_B14,
  MUSE_B15,
  MUSE_B16,
  MUSE_B17,
  MUSE_B18,
  MUSE_B19,
  MUSE_B20,
  MUSE_B21,
  MUSE_B22,
  MUSE_B23,
  MUSE_B24,
  MUSE_B25,
  MUSE_B26,
  MUSE_B27,
  MUSE_B28,
  MUSE_B29,
  MUSE_B30,
  MUSE_B31
};

bool number_of_ones_to_bool[16] = {
  1, 0, 0, 1, 0, 1, 1, 0,
  0, 1, 1, 0, 1, 0, 0, 1
};

uint8_t muse_interval[4] = {0};
uint8_t muse_theme[4] = {0};

bool timer_1bit = 0;
uint8_t timer_2bit = 0;
uint8_t timer_2bit_counter = 0;
uint8_t timer_4bit = 0;
uint32_t timer_31bit = 0;

bool bit_for_value(uint8_t value) {
  switch (value) {
    case MUSE_OFF:
      return 0;
    case MUSE_ON:
      return 1;
    case MUSE_C_1_2:
      return timer_1bit;
    case MUSE_C1:
      return (timer_4bit & 1);
    case MUSE_C2:
      return (timer_4bit & 2);
    case MUSE_C4:
      return (timer_4bit & 4);
    case MUSE_C8:
      return (timer_4bit & 8);
    case MUSE_C3:
      return (timer_2bit & 1);
    case MUSE_C6:
      return (timer_2bit & 2);
    default:
      return timer_31bit & (1UL << (value - MUSE_B1));
  }
}

uint8_t clock_pulse() {

  bool top = number_of_ones_to_bool[
    bit_for_value(muse_theme[0]) +
    bit_for_value(muse_theme[1]) << 1 +
    bit_for_value(muse_theme[2]) << 2 +
    bit_for_value(muse_theme[3]) << 3
  ];

  if (timer_1bit == 0) {
    if (timer_2bit_counter == 0) {
      timer_2bit = (timer_2bit + 1) % 4;
      timer_2bit_counter = (timer_2bit_counter + 1) % 3;
    }
    timer_4bit = (timer_4bit + 1) % 16;
    timer_31bit = (timer_31bit << 1) + top;
  }

  timer_1bit = (timer_1bit + 1) % 2;

  return
    bit_for_value(muse_interval[0]) +
    bit_for_value(muse_interval[1]) << 1 +
    bit_for_value(muse_interval[2]) << 2 +
    bit_for_value(muse_interval[3]) << 3;

}