I wrote a little ALSA app to do the same thing. Attachments aren't working so I've put it inline below (g++ -o rbd2midi_test rbd2midi.cpp -lasound to compile)
- Ed
//
// rbd2midi - convert a Rock Band (tm) usb drum event stream to midi events
//
// example usage:
//
// > # start up rbd2midi
// > rbd2midi &
// Opened "Rock Band Drums" [129:0]
//
// > # find out the available ports:
// > aconnect -i -o -l
//
// client 0: 'System' [type=kernel]
// 0 'Timer '
// 1 'Announce '
// Connecting To: 15:0
// client 14: 'Midi Through' [type=kernel]
// 0 'Midi Through Port-0'
// client 128: 'TiMidity' [type=user]
// 0 'TiMidity port 0 '
// 1 'TiMidity port 1 '
// 2 'TiMidity port 2 '
// 3 'TiMidity port 3 '
// client 129: 'Rock Band Drums' [type=user]
// 0 'Rock Band Drums '
// client 130: 'Hydrogen' [type=user]
// 0 'Hydrogen Midi-In'
//
// # connect to hydrogen (http://www.hydrogen-music.org/)
// > aconnect 129:0 130:0
//
#include <unistd.h>
#include <stdlib.h>
#include <stdio.h>
#include <linux/joystick.h>
#include <alsa/asoundlib.h>
// this is the name that other apps will see
static const char *my_name = "Rock Band Drums";
// for more printy goodness
static const int verbose = 0;
static snd_seq_t *seq_handle = NULL;
static int my_client, my_port;
static snd_seq_event_t ev;
// by allowing the user to set these and doing a snd_seq_connect_to(...)
// we could drive a midi synth directly (instead of needing aconnect)
// for now just hard-wire us as a generic application input device
static const int seq_client = SND_SEQ_ADDRESS_SUBSCRIBERS;
static const int seq_port = 0;
static const int chan_no = 0;
// the following note values seem to work for hydrogen:
static int orange_note = 36; // kick
static int red_note = 40; // rock snare
static int yellow_note = 45; // high tom
static int blue_note = 46; // open HH
static int green_note = 49; // crash
//
// close_sequencer - clean up and shut down
//
void close_sequencer()
{
if (seq_handle != NULL)
{
snd_seq_close( seq_handle );
seq_handle = NULL;
}
}
//
// open_sequencer - open the sequencer and advertise our midi input
//
int open_sequencer()
{
if (snd_seq_open( &seq_handle, "hw", SND_SEQ_OPEN_OUTPUT, 0 ) < 0)
{
fprintf( stderr, "Failed to open sequencer\n" );
return( 0 );
}
my_client = snd_seq_client_id( seq_handle );
snd_seq_set_client_name( seq_handle, my_name );
//snd_seq_set_client_group( seq_handle, "input" );
my_port = snd_seq_create_simple_port( seq_handle, my_name,
SND_SEQ_PORT_CAP_READ | SND_SEQ_PORT_CAP_SUBS_READ,
SND_SEQ_PORT_TYPE_MIDI_GENERIC | SND_SEQ_PORT_TYPE_APPLICATION );
if (my_port < 0)
{
fprintf( stderr, "Failed to create port\n" );
close_sequencer();
return 0;
}
printf( "Opened \"%s\" [%d:%d]\n", my_name, my_client, my_port );
return( 1 );
}
//
// flush_events - flush our event queue
//
static void flush_events()
{
snd_seq_drain_output( seq_handle );
}
//
// send_event - queue an event to go out of our midi port
//
static void send_event()
{
snd_seq_ev_set_direct( &ev );
snd_seq_ev_set_source( &ev, my_port );
snd_seq_ev_set_dest( &ev, seq_client, seq_port );
snd_seq_event_output( seq_handle, &ev );
// apparently you really need to flush each event?!?
flush_events();
}
//
// hit_drum - generate a drum hit or release
//
static void hit_drum( int note, int is_hit, int vel )
{
if (verbose) fprintf( stderr, "drum %d %s\n", note, is_hit ? "hit" : "off" );
is_hit ? snd_seq_ev_set_noteon( &ev, chan_no, note, vel ) : snd_seq_ev_set_noteoff( &ev, chan_no, note, 0 );
send_event();
}
//
// main - generate midi notes from joystick inputs
//
int main( int argc, char *argv[] )
{
if (!open_sequencer()) return( 0 );
int fd = open( "/dev/js0", O_RDONLY );
if (fd < 0) goto Abort;
// note sure this is necessary...
snd_seq_ev_set_controller( &ev, 0, 0, 0 );
send_event();
snd_seq_ev_set_pgmchange( &ev, chan_no, 0 );
send_event();
snd_seq_ev_set_pitchbend( &ev, chan_no, 0 );
send_event();
flush_events();
while (1)
{
struct js_event e;
while (read( fd, &e, sizeof(e) ) > 0)
{
const char *init = (e.type & JS_EVENT_INIT) ? "INIT:" : "";
const char *type = ((e.type & ~JS_EVENT_INIT) == JS_EVENT_BUTTON) ? "BUTTON" : "AXIS";
if (verbose) printf( "time %d val %d type %s%s num %d\n", e.time, e.value, init, type, e.number );
if ((e.type & ~JS_EVENT_INIT) == JS_EVENT_BUTTON)
{
switch (e.number)
{
case 0: // blue/square
hit_drum( blue_note, e.value, 127 );
break;
case 1: // green/X
hit_drum( green_note, e.value, 127 );
break;
case 2: // red/O
hit_drum( red_note, e.value, 127 );
break;
case 3: // yellow/triangle
hit_drum( yellow_note, e.value, 127 );
break;
case 4: // orange (kick)
hit_drum( orange_note, e.value, 127 );
break;
}
}
}
flush_events();
}
Abort:
if (fd >= 0) close( fd ), fd = 0;
close_sequencer();
return( 0 );
}
