path: root/src/midi.c

#include "midi.h"
#include "notes.h"
#include "control.h"

#include <string.h>

void midi_decode(uint32_t msg, synth_t * synth) {
  //  printf("MIDI message: 0x%X\n", msg);
  uint8_t status = msg;
  uint8_t data1 = (msg >> 8) & 0xFF;
  uint8_t data2 = (msg >> 16) & 0xFF;
  uint8_t channel = (status & 0x0F) + 1; // convert to human
  uint8_t message = status >> 4;

  int flag = 1;

  switch (message) {
    case 0x08:
      printf("Note Off: channel=%d, note=%d, velocity=%d\n", channel, data1, data2);
      synth->midi_note[data1].noteOff = Pa_GetStreamTime(synth->stream);
      synth->midi_note[data1].noteOffSample = synth->midi_note[data1].elapsed;
      break;
    case 0x09:
      printf("Note On: channel=%d, note=%d, velocity=%d\n", channel, data1, data2);
      //synth->midi_note[i].n = -1;
      synth->midi_note[data1].freq = notes[data1 % 12][(data1 / 12) % 8];
      synth->midi_note[data1].channel = channel;
      synth->midi_note[data1].noteOn = Pa_GetStreamTime(synth->stream);
      synth->midi_note[data1].noteOff = 0;
      synth->midi_note[data1].velocity = (float)data2 / 127.0;
      synth->midi_note[data1].elapsed = 0;
      synth->midi_note[data1].active = 1;
      for (int i = 0; i < synth->midi_active_n; i++) {
        if (synth->midi_active[i] == &synth->midi_note[data1]) {
          flag = 0;
        }
      }
      if (flag) {
        synth->midi_active[synth->midi_active_n++] = &synth->midi_note[data1];
      }
      synth->active = 1;
      break;
    case 0x0A:
      printf("Aftertouch: channel=%d, note=%d, pressure=%d\n", channel, data1, data2);
      break;
    case 0x0B:
      // printf("Control Change: channel=%d, controller=%d, value=%d\n", channel, data1, data2);
      int x = data2 < 64 ? 1 : -1;
      switch (data1) {
      case 0:
        synth->adsr.a = synth->adsr.a + (x * 0.01);
        //synth->freq_offset = synth->freq_offset + (x*5);
        //cc_step(&synth->cc_cutoff, x);
        break;
      case 1:
        synth->adsr.d = synth->adsr.d + (x * 0.01);
        break;
      case 2:
        synth->adsr.s = synth->adsr.s + (x * 0.01);
        break;
      case 3:
        synth->adsr.r = synth->adsr.r + (x * 0.01);
        break;
      case 4:
        cc_step(&synth->cc_cutoff, x);
        //synth->cutoff = synth->cutoff + (x * (10 * log10(synth->cutoff)));
        break;
      case 5:
        cc_step(&synth->cc_resonance, x);
        break;
      case 6:
        cc_step(&synth->cc_pitch, x);
        //synth->lfo.freq = synth->lfo.freq + (x * 0.1);
        break;
      case 7:
        cc_reset(&synth->cc_pitch);
        synth->lfo.amp = synth->lfo.amp + (x * 0.002);
        break;
        break;
      case 28:
        synth->filter = x - 1;
        break;
      case 29:
        break;
      default:
      }
      break;
    case 0x0C:
      printf("Program Change: channel=%d, program=%d\n", channel, data1);
      break;
    case 0x0D:
      printf("Channel Pressure: channel=%d, pressure=%d\n", channel, data1);
      break;
    case 0x0E:
      int val = ((data2 << 7) | data1) - 8192;
      printf("Pitch Bend: channel=%d, value=%d\n", channel, val);
      float pitch;
      float semitones = 2;
      if (val == 0) {
        pitch = 1;
      } else if (val > 0) {
        pitch = 1 + ((float)val / 8191) * semitones * pow(2.0, 1.0 / 12.0) / 12;
      } else {
        pitch = 1 + ((float)val / 8192) * semitones * pow(2.0, 1.0 / 12.0) / 12;
      }
      synth->cc_pitch.target = pitch;
      /* cc_step(synth->cc_pitch, 1); */
      break;
    default:
      printf("Unknown MIDI message\n");
      break;
  }
}


void
midiCallback(PtTimestamp timestamp, void *userData) {
  midi_t * m = (midi_t *)userData;

  if (!m->stream) return;

  //  if (!Pm_Poll(m->stream)) return;

  PmEvent buf;
  int e = Pm_Read(m->stream, &buf, 1);
  if (e == 0) return; // nothing to do
  if (e < 0) {
    printf("Pm_Read error %d\n", e);
    return;
  }

  //printf("%d\n", buf.message);
  midi_decode(buf.message, m->synth);
  
}

void
init_midi(midi_t *m, synth_t *synth)
{
  m->stream = NULL;
  m->synth = synth;
  
  Pm_Initialize();

  printf("midi devs: %d\n", Pm_CountDevices());
  const PmDeviceInfo *info;
  int i;
  for (i = 0; i < Pm_CountDevices(); i++) {
    info = Pm_GetDeviceInfo(i);
    printf("%d: %s [input: %d output: %d opened: %d is_virt:%d] (interf: %s) -- %d\n", i, info->name, info->input, info->output, info->opened, info->is_virtual, info->interf, Pm_GetDefaultInputDeviceID());
    //if (!strcmp("MPK225 MIDI", info->name) && !info->input) break;
    if (!strcmp("MPK225 Port A", info->name) && info->input == 1) break;
    //if (!strcmp("CH345 MIDI 1", info->name) && info->input == 1) break;
    //if (!strcmp("Midi Through Port-0", info->name) && info->input == 1) break;
    //if (!strcmp("DigitalKBD MIDI 1", info->name) && info->input == 1) break;
  }

  Pt_Start(1, midiCallback, m);

  Pm_OpenInput(&(m->stream),
               i, //Pm_GetDefaultInputDeviceID(),
               NULL,
               128,
               NULL,
               NULL);
}

void
terminate_midi(midi_t *m)
{
  Pt_Stop();
  Pm_Close(m->stream);
  Pm_Terminate();
}