Linux Joystick Mapper Git

#include <unistd.h>
#include <fcntl.h>
#include <sys/ioctl.h>
#include <linux/joystick.h>
#include <stdio.h>
#include <stdlib.h>

void print_data(int aval[], int bval[], int axes, int btns) {
    int i;
    for (i=0; i<btns; i++) {
        printf("%2d |", bval[i]);
    }
    for (i=0; i<axes; i++) {
        printf(" %5d |", aval[i]);
    }
    printf("    \r");
    fflush(stdout);
}

void print_data_hdr(int aval[], int bval[], int axes, int btns) {
    int i;
    printf("js0: axes=%d, buttons=%d\n", axes, btns);
    for (i=0; i<btns; i++) {
        printf("b%02d|", i);
    }
    for (i=0; i<axes; i++) {
        printf("  a%02d  |", i, aval[i]);
    }
    printf("\n");
    for (i=0; i<btns; i++) {
        printf("____");
    }
    for (i=0; i<axes; i++) {
        printf("________");
    }
    printf("\n");
}

int main(int argc, char *argv[]) {
    int fd,i;
    int aval[256];
    int bval[256];
    int min[256];
    int max[256];
    int dmin[256];
    int dmax[256];
    int count=0;
    int nobutton=0;
    unsigned char axes, btns;
    struct js_event ev;
    struct js_corr cor[64];
    if (argc>=2)
        fd=open(argv[1], O_RDONLY|O_NONBLOCK);
    else
        fd=open("/dev/input/js0", O_RDONLY|O_NONBLOCK);
    if (fd<0) {    
        perror("Failed to open device");
        return 1;
    }
    ioctl(fd, JSIOCGAXES, &axes);
    ioctl(fd, JSIOCGBUTTONS, &btns);
    for (i=0; i<64; i++) {
        cor[i].type=JS_CORR_NONE;
        cor[i].coef[0]=128;
        cor[i].coef[1]=128;
        cor[i].coef[2]=65536*64;
        cor[i].coef[3]=65536*64;
    }
    ioctl(fd, JSIOCSCORR, cor);

    printf("Leave all axes centred, press a button when ready\n");
    print_data_hdr(aval, bval, axes, btns);

    for (i=0; i<axes; i++) aval[i]=128;
    for (i=0; i<axes; i++) bval[i]=0;
    //get initial values;
    nobutton=0;
    while (nobutton==0) {
        while (read(fd, &ev, sizeof(ev))==sizeof(ev)) {
            if (ev.type&JS_EVENT_BUTTON)
                bval[ev.number]=ev.value;
            if (ev.type&JS_EVENT_AXIS)
                aval[ev.number]=ev.value;
        }
        print_data(aval, bval, axes, btns);
        nobutton=0;
        for (i=0; i<btns; i++) nobutton+=bval[i];
    }
    //set initial deadzone
    for (i=0; i<axes; i++) dmin[i]=dmax[i]=aval[i];
    nobutton=0;
    
    //wait five seconds for scan of deadzone
    count=0;
    while (count<500) {
        while (read(fd, &ev, sizeof(ev))==sizeof(ev)) {
            if (ev.type&JS_EVENT_BUTTON)
                bval[ev.number]=ev.value;
            if (ev.type&JS_EVENT_AXIS) {
                aval[ev.number]=ev.value;
                if (aval[ev.number]<dmin[ev.number])
                    dmin[ev.number]=aval[ev.number];
                if (aval[ev.number]>dmax[ev.number])
                    dmax[ev.number]=aval[ev.number];
            }
        }
        print_data(aval, bval, axes, btns);
        usleep(1000);
        count++;
    }


    for (i=0; i<axes; i++) min[i]=max[i]=aval[i];
    printf("\n\n");
    printf("Move axes through complete range of motion.\n");
    printf("Press a button when complete\n");
    print_data_hdr(aval, bval, axes, btns);
    while (nobutton==0) {
        while (read(fd, &ev, sizeof(ev))==sizeof(ev)) {
            if (ev.type&JS_EVENT_BUTTON)
                bval[ev.number]=ev.value;
            if (ev.type&JS_EVENT_AXIS) {
                aval[ev.number]=ev.value;
                if (aval[ev.number]<min[ev.number])
                    min[ev.number]=aval[ev.number];
                if (aval[ev.number]>max[ev.number])
                    max[ev.number]=aval[ev.number];
            }
        }
        print_data(aval, bval, axes, btns);
        nobutton=0;
        for (i=0; i<btns; i++) nobutton+=bval[i];
    }
    printf("\n");
    for (i=0; i<axes; i++) {
        cor[i].type=JS_CORR_BROKEN;
        printf("%d: %d %d %d %d\n", i, dmin[i], dmax[i], min[i], max[i]);
        if (max[i]==dmax[i]) dmax[i]=max[i]-1;
        if (min[i]==dmin[i]) dmin[i]=min[i]+1;
        cor[i].coef[0]=dmin[i];
        cor[i].coef[1]=dmax[i];
        cor[i].coef[2]=32768*16384/(dmin[i]-min[i]);
        cor[i].coef[3]=32768*16384/(max[i]-dmax[i]);
    }
    ioctl(fd, JSIOCSCORR, cor);
    return 0;
}