Commit | Line | Data |
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f2e16dc5 H |
1 | /* Modified code from http://tldp.org/HOWTO/MIDI-HOWTO-9.html |
2 | * This will print ALSA-Seq (MIDI) events to stdout for further processing eg.: in Arduino | |
3 | */ | |
4 | ||
5 | #include <stdio.h> | |
6 | #include <stdlib.h> | |
7 | #include <unistd.h> | |
8 | #include <alsa/asoundlib.h> | |
9 | ||
10 | #define MIDI_NOTE_OFF 128 | |
11 | #define MIDI_NOTE_ON 144 | |
12 | #define MIDI_CONTROL 176 | |
13 | #define MIDI_PITCH_BEND 224 | |
359fba90 H |
14 | #define MIDI_FORMAT "%c%c%c" |
15 | #define MIDI_FORMAT_ERR "%d:%d:%d\n" | |
f2e16dc5 H |
16 | |
17 | snd_seq_t *open_seq(); | |
18 | void midi_action(snd_seq_t *seq_handle); | |
19 | ||
20 | snd_seq_t *open_seq() { | |
21 | ||
22 | snd_seq_t *seq_handle; | |
23 | int portid; | |
24 | ||
25 | if (snd_seq_open(&seq_handle, "hw", SND_SEQ_OPEN_DUPLEX, 0) < 0) { | |
26 | fprintf(stderr, "Error opening ALSA sequencer.\n"); | |
27 | exit(1); | |
28 | } | |
29 | snd_seq_set_client_name(seq_handle, "ALSA Sequencer Pipe"); | |
30 | if ((portid = snd_seq_create_simple_port(seq_handle, "ALSA Sequencer Pipe", | |
31 | SND_SEQ_PORT_CAP_WRITE|SND_SEQ_PORT_CAP_SUBS_WRITE, | |
32 | SND_SEQ_PORT_TYPE_APPLICATION)) < 0) { | |
33 | fprintf(stderr, "Error creating sequencer port.\n"); | |
34 | exit(1); | |
35 | } | |
36 | return(seq_handle); | |
37 | } | |
38 | ||
39 | void midi_action(snd_seq_t *seq_handle) { | |
40 | ||
41 | snd_seq_event_t *ev; | |
42 | ||
43 | do { | |
44 | snd_seq_event_input(seq_handle, &ev); | |
45 | switch (ev->type) { | |
46 | case SND_SEQ_EVENT_CONTROLLER: | |
47 | printf(MIDI_FORMAT, MIDI_CONTROL, ev->data.control.channel, ev->data.control.value); | |
48 | break; | |
49 | case SND_SEQ_EVENT_PITCHBEND: | |
50 | printf(MIDI_FORMAT, MIDI_PITCH_BEND, ev->data.control.channel, ev->data.control.value); | |
51 | break; | |
52 | case SND_SEQ_EVENT_NOTEON: | |
53 | printf(MIDI_FORMAT, MIDI_NOTE_ON, ev->data.control.channel, ev->data.note.note); | |
54 | break; | |
55 | case SND_SEQ_EVENT_NOTEOFF: | |
56 | printf(MIDI_FORMAT, MIDI_NOTE_OFF, ev->data.control.channel, ev->data.note.note); | |
57 | break; | |
58 | } | |
359fba90 | 59 | fflush(stdout); fflush(stderr); |
f2e16dc5 H |
60 | snd_seq_free_event(ev); |
61 | } while (snd_seq_event_input_pending(seq_handle, 0) > 0); | |
62 | } | |
63 | ||
64 | int main(int argc, char *argv[]) { | |
65 | ||
66 | snd_seq_t *seq_handle; | |
67 | int npfd; | |
68 | struct pollfd *pfd; | |
69 | ||
70 | seq_handle = open_seq(); | |
71 | npfd = snd_seq_poll_descriptors_count(seq_handle, POLLIN); | |
72 | pfd = (struct pollfd *)alloca(npfd * sizeof(struct pollfd)); | |
73 | snd_seq_poll_descriptors(seq_handle, pfd, npfd, POLLIN); | |
74 | ||
75 | fprintf(stderr, "COMMAND:CHANNEL:NOTE\nCommands are described on http://www.ec.vanderbilt.edu/computermusic/musc216site/MIDI.Commands.html\n\n"); | |
76 | while (1) { | |
77 | if (poll(pfd, npfd, 100000) > 0) { | |
78 | midi_action(seq_handle); | |
79 | } | |
80 | } | |
81 | } |