#include <stdio.h>
#include <string.h>
#include <unistd.h>
#include <fcntl.h>
#include <linux/uinput.h>
#include <stdlib.h>
#define msleep(ms) usleep((ms)*1000)
// miditest3.c
// midi to uinput button test mapping notes to buttons, and mod/pitch/volume to axes
// by Golden Child
// just maps the low register of the keyboard into button pressess
// using examples from
//
// https://gist.github.com/matthewaveryusa/a721aad80ae89a5c69f7c964fa20fec1
// https://github.com/GrantEdwards/uinput-joystick-demo
// https://www.kernel.org/doc/html/v4.12/input/uinput.html
// https://blog.marekkraus.sk/c/linuxs-uinput-usage-tutorial-virtual-gamepad/
static void setup_abs(int fd, unsigned chan, int min, int max);
int main(int argc, char* argv[])
{
int midi_fd = open("/dev/midi1", O_RDONLY | O_NONBLOCK);
if (midi_fd < 0)
{
perror("open /dev/midi1");
return 1;
}
//sleep(1); // wait for a second
int fd = open("/dev/uinput", O_WRONLY | O_NONBLOCK);
if (fd < 0)
{
perror("open /dev/uinput");
return 1;
}
ioctl(fd, UI_SET_EVBIT, EV_KEY); // enable button/key handling
// event codes from linux/input-event-codes.h
int translatetable[] = {
0xc, BTN_0,
0xd, BTN_1,
0xe, BTN_2,
0xf, BTN_3,
0x10, BTN_4,
0x11, BTN_5,
0x12, BTN_6,
0x13, BTN_7,
0x14, BTN_8,
0x15, BTN_9,
0x16, BTN_TRIGGER_HAPPY1,
0x17, BTN_TRIGGER_HAPPY2,
0x18, BTN_DPAD_UP,
0x19, BTN_DPAD_LEFT,
0x1a, BTN_DPAD_DOWN,
0x1b, BTN_DPAD_RIGHT,
0x1c, 0x2ff,
0x1d, 0x280, // 0x300 doesn't work
0x1e, 0x2F0, // 2F0 seems to be undefined but works
0x1f, 0x2F1,
0x20, 0x224, // 224 - 22f undefined
0x21, 0x22f,
0x22, 0x120,
0x23, 0x12f,
0x24, 0x130,
0x25, 0x13e }; // greater than 0x2ff key max doesn't show up as a button press
int translatetablelen = sizeof(translatetable) / sizeof (int);
// tell uinput which BTN events we will generate
for (int i=0;i<translatetablelen;i+=2) ioctl(fd, UI_SET_KEYBIT, translatetable[i+1]);
for (int i=0;i<translatetablelen;i+=2) printf("%d => %d\n",translatetable[i],translatetable[i+1]);
ioctl(fd, UI_SET_EVBIT, EV_ABS); // enable analog absolute position handling
// setup_abs(fd, ABS_X, -512, 512);
// setup_abs(fd, ABS_Y, -512, 512);
// setup_abs(fd, ABS_Z, 0, 32767);
setup_abs(fd, ABS_X, 0, 127);
setup_abs(fd, ABS_Y, 0, 127);
setup_abs(fd, ABS_Z, 0, 127);
struct uinput_setup setup =
{
.name = "Userspace Joystick",
.id =
{
.bustype = BUS_USB,
.vendor = 0x3,
.product = 0x3,
.version = 2,
}
};
if (ioctl(fd, UI_DEV_SETUP, &setup))
{
perror("UI_DEV_SETUP");
return 1;
}
if (ioctl(fd, UI_DEV_CREATE))
{
perror("UI_DEV_CREATE");
return 1;
}
printf("Press CTRL+C to exit or top key on keyboard to quit\n");
struct input_event button_event;
unsigned char buffer[256];
int doquit = 0;
while (1) {
int readval;
if ( readval = read(midi_fd, &buffer, 3), readval != -1 ) {
printf("read: %x %x %x\n",buffer[0],buffer[1],buffer[2]);
if (buffer[0] == 0x90) // note on/off convert to EV_KEY events
{ if (buffer[1] == 0x3c) doquit = 1;
for (int i=0;i<translatetablelen;i+=2)
if (buffer[1] == translatetable[i])
{
button_event.type = EV_KEY;
button_event.code = translatetable[i+1];
button_event.value = (buffer[2]!=0) ? 1 : 0; // 1 for button down, 0 for button up
printf("readval=%d ev type=%d key in=%d => button out=%d value=%d\n",
readval,
button_event.type,
buffer[1],
button_event.code,
button_event.value);
if(write(fd, &button_event, sizeof button_event) < 0)
{
perror("write");
return 1;
}
// send SYNC event
button_event.type = EV_SYN;
button_event.code = 0;
button_event.value = 0;
if(write(fd, &button_event, sizeof button_event) < 0)
{
perror("write");
return 1;
}
}
}
else if (buffer[0]==0xb0) // convert midi controller message into EV_ABS events
{
button_event.type = EV_ABS;
button_event.code = (buffer[1]==1) ? ABS_X : (buffer[1]==7) ? ABS_Y : 0; // my midi keyboard has 1 for volume, 7 for modulation
button_event.value = (buffer[2]);
printf("0xb0 readval=%d ev type=%d key in=%d => button out=%d value=%d\n",
readval,
button_event.type,
buffer[1],
button_event.code,
button_event.value);
if(write(fd, &button_event, sizeof button_event) < 0)
{
perror("write");
return 1;
}
// send SYNC event
button_event.type = EV_SYN;
button_event.code = 0;
button_event.value = 0;
if(write(fd, &button_event, sizeof button_event) < 0)
{
perror("write");
return 1;
}
}
else if (buffer[0]==0xe0) // pitch bend wheel message to EV_ABS event
{
button_event.type = EV_ABS;
button_event.code = ABS_Z;
button_event.value = (buffer[2]);
printf("0xb0 readval=%d ev type=%d key in=%d => button out=%d value=%d\n",
readval,
button_event.type,
buffer[1],
button_event.code,
button_event.value);
if(write(fd, &button_event, sizeof button_event) < 0)
{
perror("write");
return 1;
}
// send SYNC event
button_event.type = EV_SYN;
button_event.code = 0;
button_event.value = 0;
if(write(fd, &button_event, sizeof button_event) < 0)
{
perror("write");
return 1;
}
}
}
if (readval <=0) msleep(50); // sleep for a bit so we don't use all the cpu
if (doquit) break;
}
close(midi_fd);
if(ioctl(fd, UI_DEV_DESTROY))
{
printf("UI_DEV_DESTROY");
return 1;
}
close(fd);
return 0;
}
// enable and configure an absolute "position" analog channel
static void setup_abs(int fd, unsigned chan, int min, int max)
{
if (ioctl(fd, UI_SET_ABSBIT, chan))
perror("UI_SET_ABSBIT");
struct uinput_abs_setup s =
{
.code = chan,
.absinfo = { .minimum = min, .maximum = max },
};
if (ioctl(fd, UI_ABS_SETUP, &s))
perror("UI_ABS_SETUP");
}
![[Linked Image from i.imgur.com]](https://i.imgur.com/1FamNxn.png)
