wernermisc/midi2osc/midi2osc.c

/*
 * midi2osc.c - MIDI to OSC forwarder
 *
 * Written 2011 by Werner Almesberger
 * Copyright 2011 Werner Almesberger
 *
 * 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.
 */


#include <stdint.h>
#include <stdlib.h>
#include <stdio.h>
#include <alsa/asoundlib.h>
#include "lo/lo.h"


#define	NAME "midi2osc"


static void forward(snd_seq_t *midi, lo_address osc)
{
	snd_seq_event_t *ev;
	uint8_t msg[4] = { 0, };

	while (snd_seq_event_input(midi, &ev)) {
		switch (ev->type) {
		case SND_SEQ_EVENT_NOTEON:
			msg[1] = 0x90 | ev->data.control.channel;
			msg[2] = ev->data.note.note;
			msg[3] = ev->data.note.velocity;
			break;
		case SND_SEQ_EVENT_CONTROLLER:
			msg[1] = 0xb0 | ev->data.control.channel;
			msg[2] = ev->data.control.param;
			msg[3] = ev->data.control.value;
			break;
		case SND_SEQ_EVENT_PITCHBEND:
			msg[1] = 0xe0 | ev->data.control.channel;
			msg[2] = ev->data.control.value;
			msg[3] = 0;
			break;
		default:
			/* Flickernoise currently doesn't support any others */
			snd_seq_free_event(ev);
			continue;
		}
		if (lo_send(osc, "/midi", "m", msg) < 0)
			fprintf(stderr, "%s\n", lo_address_errstr(osc));
		snd_seq_free_event(ev);
	}
}


static void usage(const char *name)
{
	fprintf(stderr, "usage: %s hostname [port]\n", name);
	exit(1);
}


int main(int argc, char **argv)
{
	const char *port = "4444";	/* Milkymist One OSC port */
	lo_address osc;
	snd_seq_t *midi;

	switch (argc) {
	case 2:
		break;
	case 3:
		port = argv[2];
		break;
	default:
		usage(*argv);
	}

	osc = lo_address_new(argv[1], port);
	if (!osc) {
		fprintf(stderr, "invalid address %s %s\n", argv[1], port);
		exit(1);
	}

	if (snd_seq_open(&midi, "hw", SND_SEQ_OPEN_INPUT,0) < 0) {
		fprintf(stderr, "can't open ALSA sequencer\n");
		exit(1);
	}
	snd_seq_set_client_name(midi, NAME);
	if (snd_seq_create_simple_port(midi, NAME,
              SND_SEQ_PORT_CAP_WRITE | SND_SEQ_PORT_CAP_SUBS_WRITE,
              SND_SEQ_PORT_TYPE_APPLICATION) < 0) {
		fprintf(stderr, "can't create sequencer port\n");
		exit(1);
	}

	forward(midi, osc);

	return 0;
}