flightgear/utils/js_server/js_server.cxx

/*
     Plib based joystick server based on PLIBs js_demo.cxx

     js_server is Copyright (C) 2003 
     by Stephen Lowry and Manuel Bessler

     PLIB - A Suite of Portable Game Libraries
     Copyright (C) 2001  Steve Baker

     This program is free software; you can redistribute it and/or modify
     it under the terms of the GNU General Public License as published by
     the Free Software Foundation; either version 2 of the License, or
     (at your option) any later version.

     This program is distributed in the hope that it will be useful,
     but WITHOUT ANY WARRANTY; without even the implied warranty of
     MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
     GNU General Public License for more details.

     You should have received a copy of the GNU General Public License
     along with this program; if not, write to the Free Software
     Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA.

     For further information visit http://plib.sourceforge.net

*/

#include <math.h>
#include <memory>
#include <stdint.h>
#include <stdio.h>

#include <plib/netSocket.h>

#include "FlightGear_js.h"

void usage(char* progname)
{
    printf("This is an UDP based remote joystick server.\n");
    printf("usage: %s <hostname> <port>\n", progname);
}

int main(int argc, char** argv)
{
    int port = 16759;
    char* host; /* = "192.168.1.7"; */
    int activeaxes = 4;

    if (argc != 3) {
        usage(argv[0]);
        exit(1);
    }
    host = argv[1];
    port = atoi(argv[2]);

    jsInit();

    auto js = std::make_unique<jsJoystick>(0);

    if (js->notWorking()) {
        printf("no Joystick detected... exitting\n");
        exit(1);
    }
    printf("Joystick is \"%s\"\n", js->getName());

    int numaxes = js->getNumAxes();
    auto ax = std::make_unique<float[]>(numaxes);
    activeaxes = numaxes;

    if (numaxes > 4) {
        printf("max 4 axes joysticks supported at the moment, however %i axes were detected\nWill only use the first 4 axes!\n", numaxes);
        activeaxes = 4;
    }

    // Must call this before any other net stuff
    netInit(&argc, argv);

    netSocket c;

    if (!c.open(false)) { // open a UDP socket
        printf("error opening socket\n");
        return -1;
    }

    c.setBlocking(false);

    if (c.connect(host, port) == -1) {
        printf("error connecting to %s:%d\n", host, port);
        return -1;
    }

    char packet[256] = "Hello world!";
    while (1) {
        int b;
        int len = 0;
        int axis = 0;

        js->read(&b, ax.get());
        for (axis = 0; axis < activeaxes; axis++) {
            int32_t axisvalue = (int32_t)(ax[axis] * 2147483647.0);
            printf("axisval=%li\n", (long)axisvalue);
            memcpy(packet + len, &axisvalue, sizeof(axisvalue));
            len += sizeof(axisvalue);
        }
        // fill emtpy values into packes when less than 4 axes
        for (; axis < 4; axis++) {
            int32_t axisvalue = 0;
            memcpy(packet + len, &axisvalue, sizeof(axisvalue));
            len += sizeof(axisvalue);
        }

        int32_t b_l = b;
        memcpy(packet + len, &b_l, sizeof(b_l));
        len += sizeof(b_l);

        const char* termstr = "\0\0\r\n";
        memcpy(packet + len, termstr, 4);
        len += 4;

        c.send(packet, len, 0);

        /* give other processes a chance */

#ifdef _WIN32
        Sleep(1);
#elif defined(sgi)
        sginap(1);
#else
        usleep(200);
#endif
        printf(".");
        fflush(stdout);
    }

    return 0;
}