root/trunk/jack/example-clients/midiseq.c

/*
    Copyright (C) 2004 Ian Esten
    
    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, write to the Free Software
    Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
*/

#include <jack/jack.h>
#include <jack/midiport.h>
#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>

jack_client_t *client;
jack_port_t *output_port;

unsigned char* note_frqs;
jack_nframes_t* note_starts;
jack_nframes_t* note_lengths;
jack_nframes_t num_notes;
jack_nframes_t loop_nsamp;
jack_nframes_t loop_index;

void usage()
{
        fprintf(stderr, "usage: jack_midiseq name nsamp [startindex note nsamp] ...... [startindex note nsamp]\n");
        fprintf(stderr, "eg: jack_midiseq Sequencer 24000 0 60 8000 12000 63 8000\n");
        fprintf(stderr, "will play a 1/2 sec loop (if srate is 48khz) with a c4 note at the start of the loop\n");
        fprintf(stderr, "that lasts for 12000 samples, then a d4# that starts at 1/4 sec that lasts for 800 samples\n");
}

int process(jack_nframes_t nframes, void *arg)
{
        int i,j;
        void* port_buf = jack_port_get_buffer(output_port, nframes);
        unsigned char* buffer;
        jack_midi_clear_buffer(port_buf);
        /*memset(buffer, 0, nframes*sizeof(jack_default_audio_sample_t));*/

        for(i=0; i<nframes; i++)
        {
                for(j=0; j<num_notes; j++)
                {
                        if(note_starts[j] == loop_index)
                        {
                                buffer = jack_midi_event_reserve(port_buf, i, 3);
/*                              printf("wrote a note on, port buffer = 0x%x, event buffer = 0x%x\n", port_buf, buffer);*/
                                buffer[2] = 64;         /* velocity */
                                buffer[1] = note_frqs[j];
                                buffer[0] = 0x90;       /* note on */
                        }
                        else if(note_starts[j] + note_lengths[j] == loop_index)
                        {
                                buffer = jack_midi_event_reserve(port_buf, i, 3);
/*                              printf("wrote a note off, port buffer = 0x%x, event buffer = 0x%x\n", port_buf, buffer);*/
                                buffer[2] = 64;         /* velocity */
                                buffer[1] = note_frqs[j];
                                buffer[0] = 0x80;       /* note off */
                        }
                }
                loop_index = loop_index+1 >= loop_nsamp ? 0 : loop_index+1;
        }
        return 0;
}

int main(int narg, char **args)
{
        int i;
        jack_nframes_t nframes;
        if((narg<6) || ((narg-3)%3 !=0))
        {
                usage();
                exit(1);
        }
        if((client = jack_client_open (args[1], JackNullOption, NULL)) == 0)
        {
                fprintf (stderr, "jack server not running?\n");
                return 1;
        }
        jack_set_process_callback (client, process, 0);
        output_port = jack_port_register (client, "out", JACK_DEFAULT_MIDI_TYPE, JackPortIsOutput, 0);
        nframes = jack_get_buffer_size(client);
        loop_index = 0;
        num_notes = (narg - 3)/3;
        note_frqs = malloc(num_notes*sizeof(unsigned char));
        note_starts = malloc(num_notes*sizeof(unsigned char));
        note_lengths = malloc(num_notes*sizeof(jack_nframes_t));
        loop_nsamp = atoi(args[2]);
        for(i=0; i<num_notes; i++)
        {
                note_starts[i] = atoi(args[3 + 3*i]);
                note_frqs[i] = atoi(args[4 + 3*i]);
                note_lengths[i] = atoi(args[5 + 3*i]);
        }

        if (jack_activate(client))
        {
                fprintf (stderr, "cannot activate client");
                return 1;
        }

        while (1)
        {
                sleep(1);
        };
        
}