exemplos-compmus/_examples/c/alsamidi2.c

87 lines
2.2 KiB
C

---
author: "Flávio Schiavoni"
description: Obla !
---
#include <signal.h>
#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <alsa/asoundlib.h>
extern struct timespec timespec_diff(struct timespec start, struct timespec end);
extern double timespec_millis(struct timespec time);
snd_seq_t *open_seq();
void midi_action(snd_seq_t *seq_handle);
int keep_walking;
static void sigint_handler(int i){
keep_walking = 0;
}
int main(int argc, char *argv[]) {
int note_on_time = 1000000; // 1 segundo
int note_off_time = 1000000; // 1 segundo (em microsegundos)
signal(SIGINT, &sigint_handler);
signal(SIGTERM, &sigint_handler);
keep_walking = 1;
// Crio o dispositivo MIDI
snd_seq_t *seq_handle;
int portid;
if (snd_seq_open(&seq_handle, "hw", SND_SEQ_OPEN_DUPLEX, 0) < 0) {
fprintf(stderr, "Error opening ALSA sequencer.\n");
exit(1);
}
snd_seq_set_client_name(seq_handle, "Teclado");
if ((portid = snd_seq_create_simple_port(seq_handle, "keyb",
SND_SEQ_PORT_CAP_READ|SND_SEQ_PORT_CAP_SUBS_READ,
SND_SEQ_PORT_TYPE_APPLICATION)) < 0) {
fprintf(stderr, "Error creating sequencer port.\n");
exit(1);
}
snd_seq_event_t ev;
snd_seq_ev_clear(&ev);
snd_seq_ev_set_source(&ev, 0);
snd_seq_ev_set_subs(&ev);
snd_seq_ev_set_direct(&ev);
while (keep_walking) {
int key = getchar();
printf("Pressionou o %d\n", key);
switch(key){
case 'a':
snd_seq_ev_set_noteon(&ev, 0, 60, 127);
snd_seq_event_output(seq_handle, &ev);
snd_seq_drain_output(seq_handle);
usleep(note_on_time / 3);
snd_seq_ev_set_noteoff(&ev, 0, 60, 0);
snd_seq_event_output(seq_handle, &ev);
snd_seq_drain_output(seq_handle);
break;
case 's':
snd_seq_ev_set_noteon(&ev, 0, 62, 127);
snd_seq_event_output(seq_handle, &ev);
snd_seq_drain_output(seq_handle);
usleep(note_on_time / 3);
snd_seq_ev_set_noteoff(&ev, 0, 62, 0);
snd_seq_event_output(seq_handle, &ev);
snd_seq_drain_output(seq_handle);
}
}
snd_seq_close(seq_handle);
return 0;
}