sekai/examples/realtime_demo/jack.cpp

/*

  Author: Harry van Haaren
  E-mail: harryhaaren@gmail.com
  Copyright (C) 2010 Harry van Haaren
  Copyright (C) 2015 Tobias Platen


  PrintSynth 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 3 of the License, or
  (at your option) any later version.

  PrintJackMidi 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 PrintJackMidi.  If not, see <http://www.gnu.org/licenses/>. */

#include "jack.hpp"
#include <unistd.h>
#include "midi.h"

using namespace std;

Jack::Jack() {
  std::cout << "Jack()" << std::flush;

  if ((client = jack_client_open("SampleMidiSynth", JackNullOption, NULL)) ==
      0) {
    std::cout << "jack server not running?" << std::endl;
  }

  synth.init(jack_get_sample_rate(client), jack_get_buffer_size(client));
  bufferSize = jack_get_buffer_size(client);

  inputPort = jack_port_register(client, "midi_in", JACK_DEFAULT_MIDI_TYPE,
                                 JackPortIsInput, 0);
  outputPort = jack_port_register(client, "audio_out", JACK_DEFAULT_AUDIO_TYPE,
                                  JackPortIsOutput, 0);

  inputBuffer = jack_ringbuffer_create(4096);
  outputBuffer = jack_ringbuffer_create(4096 * sizeof(float));

  jack_set_process_callback(client, staticProcess, static_cast<void *>(this));

  std::cout << "\t\t\tDone!" << std::endl;
}

Jack::~Jack() { std::cout << "~Jack()" << std::endl; }

void Jack::activate() {
  std::cout << "activate()" << std::flush;

  if (jack_activate(client) != 0) {
    std::cout << "cannot activate client" << std::endl;
    return;
  }
  std::cout << "\t\tDone!" << std::endl;

  jack_connect(client, "a2j:MIDIMATE II [20] (capture): MIDIMATE II MIDI 1",
               "SampleMidiSynth:midi_in");
  jack_connect(client, "SampleMidiSynth:audio_out", "system:playback_1");
  jack_connect(client, "SampleMidiSynth:audio_out", "system:playback_2");

  std::thread *thr = new std::thread(Jack::staticWorkerThread, this);
  (void) thr;
}

int Jack::staticProcess(jack_nframes_t nframes, void *arg) {
  return static_cast<Jack *>(arg)->process(nframes);
}

int Jack::process(jack_nframes_t nframes) {
  jack_midi_event_t in_event;
  //jack_nframes_t event_index = 0;
  //jack_position_t position;
  //jack_transport_state_t transport;

  // get the port data
  void *inputPortBuf = jack_port_get_buffer(inputPort, nframes);
  //void *outputPortBuf = jack_port_get_buffer(outputPort, nframes);

  jack_nframes_t event_count = jack_midi_get_event_count(inputPortBuf);
  if (event_count > 0) {
    for (uint i = 0; i < event_count; i++) {
      jack_midi_event_get(&in_event, inputPortBuf, i);

      unsigned char event[4];
      event[0] = 0;
      event[1] = in_event.buffer[0];
      event[2] = in_event.buffer[1];
      event[3] = in_event.buffer[2];
      if (jack_ringbuffer_write_space(inputBuffer) > 4) {
        jack_ringbuffer_write(inputBuffer, (char *)event, 4);
      }
    }
  }

  jack_default_audio_sample_t *out =
      (jack_default_audio_sample_t *)jack_port_get_buffer(outputPort, nframes);

  if (jack_ringbuffer_read_space(outputBuffer) > nframes * sizeof(float) * 2) {
    jack_ringbuffer_read(outputBuffer, (char *)out, nframes * sizeof(float));
  }

  return 0;
}

void Jack::staticWorkerThread(Jack *self) {
  fprintf(stderr, "worker thread - non realtime\n");
  while (1) {
    if (jack_ringbuffer_read_space(self->inputBuffer) >= 4) {
      unsigned char event[4];
      jack_ringbuffer_read(self->inputBuffer, (char *)event, 4);
      int sb = event[1];
      int arg1 = event[2];
      int arg2 = event[3];

      if (MIDI_STATUS(sb) == MIDI_NOTEOFF ||
          (MIDI_STATUS(sb) == MIDI_NOTEON && arg2 == 0))
        self->synth.noteOff(arg1);
      else if (MIDI_STATUS(sb) == MIDI_NOTEON)
        self->synth.noteOn(arg1, arg2);
      else if (MIDI_STATUS(sb) == MIDI_CONTROLLER)
        self->synth.controllerEvent(arg1, arg2);
      else if (MIDI_STATUS(sb) == MIDI_PITCHBEND)
        self->synth.pitchBend(arg1, arg2);
    }
    if (jack_ringbuffer_write_space(self->outputBuffer) >=
        self->bufferSize * sizeof(float)) {
      float buffer[self->bufferSize];
      self->synth.fill(buffer, self->bufferSize);
      jack_ringbuffer_write(self->outputBuffer, (char *)buffer,
                            self->bufferSize * sizeof(float));
    }
    usleep(1000);
  }
}