path: root/src/midi.c

#include "midi.h"
#include "notes.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;

  switch (message) {
    case 0x08:
      printf("Note Off: channel=%d, note=%d, velocity=%d\n", channel, data1, data2);
      if (synth->n.key == data1) {
        synth->n.noteOff = Pa_GetStreamTime(synth->stream);
      }
      break;
    case 0x09:
      printf("Note On: channel=%d, note=%d, velocity=%d\n", channel, data1, data2);
      synth->n.key = data1;
      synth->n.freq = notes[data1 % 12][(data1 / 12) % 8];
      synth->n.noteOn = Pa_GetStreamTime(synth->stream);
      synth->n.noteOff = 0;
      synth->n.elapsed = 0;
      synth->adsr.elapsed = 0;
      synth->active = 1;
      synth->gain = data2 / 127.0;

      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);
      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:
      printf("Pitch Bend: channel=%d, value=%d\n", channel, ((data2 << 7) | data1) - 8192);
      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;
  Pm_Read(m->stream, &buf, 1);

  //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;
  }

  Pt_Start(1, midiCallback, m);

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

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