[.. upper level ..]

VG3_keys_nw_addkeys()

  #include <stdio.h>
  #include <stdlib.h>
  #include <string.h>
  #include <sys/types.h>
  #include <unistd.h>
  #include <vgagames3.h>

  /* define key reference number, just one indicating pressing the key */
  #define KEYREF_PRESSED 1

  /* output text centered onto the window */
  static void
  print_text(struct vg3_window *wstruct, const char *text)
  {
    struct vg3_rect rect;
    struct vg3_text stxt;
    int w0, h0;

    if (wstruct == NULL || text == NULL || *text == '\0') { return; }

    VG3_window_getsize(wstruct, &w0, &h0);

    VG3_draw_clear(wstruct, NULL, VGAG3_COLOR_BLACK);
    VGAG3_TEXT_ATTRIBUTES_SET(&stxt, NULL, '\n', 0, text);
    rect.x = rect.y = 0; rect.w = w0; rect.h = h0;
    rect = VG3_draw_text(wstruct, NULL, &rect, 0, &stxt, VGAG3_COLOR_YELLOW, VGAG3_COLOR_BLACK, 1);
    rect.x = w0 / 2 - rect.w / 2; rect.y = h0 / 2 - rect.h / 2;
    VG3_draw_text(wstruct, NULL, &rect, 0, &stxt, VGAG3_COLOR_YELLOW, VGAG3_COLOR_BLACK, 0);
    rect.x--; rect.y--; rect.w += 2; rect.h += 2;
    VG3_draw_rect(wstruct, NULL, &rect, 0, VGAG3_COLOR_YELLOW);
  }


  /* main program */
  int main(int argc, char **argv) {
    struct vg3_window *wstruct;
    struct vg3_nwclient *nwptr;
    int retw, is_master, masterbyte, clnr, clmax, cli, dowait, jid;
    char remhost[128], *ipsrv, buf[256], *sysm_string;
    struct vg3_sysmenu *sysm;
    struct vg3_sysmenu_submenu *subm_keyb, *subm_gc;
    struct vg3_keys *skeys;
    FILE *ffp;

    /* called with parameter "-m" indicates master-client */
    is_master = masterbyte = 0;
    if (argc >= 2 && strcmp(argv[1], "-m") == 0) { is_master = 1, masterbyte = 1; printf("MASTER\n"); }

    /* master starts multicast/broadcast server and network server */
    if (is_master) {
      VG3_nw_mbcast_start();
      VG3_nw_server(NULL);
    }

    /* open window */
    wstruct = VG3_window_new(argv[0], VGAG3_VGAVERSION_LOW, VGAG3_WINSCALE_NOSCALE);
    if (wstruct == NULL) { fprintf(stderr, "%s\n", VG3_error()); exit(1); }

    retw = 0;

    /* don't catch mouse */
    VG3_mouserelease(wstruct, VGAG3_KEY_NOKEY);

    /* create system menu
     * - install exit menu
     * - install empty keyboard submenu
     * - install empty gamecontroller submenu,
     *   but only if at least one gamecontroller/joystick is found
     * variables:
     * - "sysm" gets system menu
     * - "subm_keyb" gets keyboard submenu
     * - "subm_gc" gets gamecontroller submenu or is set to NULL
     */
    sysm = VG3_sysmenu_new(wstruct, NULL, VG3_color_brightness(VGAG3_COLOR_GREEN, 50), VGAG3_COLOR_GREEN);
    VG3_sysmenu_simple_exitmenu(sysm, NULL, "Exit game");
    subm_keyb = VG3_sysmenu_simple_keyboardmenu(sysm, NULL);
    subm_gc = NULL;
    if (VG3_gamecontroller_getall(wstruct, NULL) > 0) { subm_gc = VG3_sysmenu_simple_gcmenu(sysm, NULL); }

    /* read saved key definitions for system menu from file */
    if ((ffp = fopen("nwkeys.keysave", "r")) != NULL) {
      fgets(buf, sizeof(buf), ffp);
      fclose(ffp);
    } else {
      *buf = '\0';
    }
    sysm_string = strdup(buf);

    /* initialize keys-struct for simplifying key-handling with system menu (and network) */
    skeys = VG3_keys_new(wstruct, sysm);
    if (skeys == NULL) { fprintf(stderr, "%s\n", VG3_error()); retw = 1; goto endgame; }

    /* insert KEYREF_PRESSED into keyboard submenu and possibly gamecontroller submenu */
    VG3_keys_menu_insert(skeys, sysm_string, NULL,
                         KEYREF_PRESSED, "Key pressed", "Key pressed",
                         subm_keyb, VGAG3_KEY_SPACE,
                         subm_gc, VGAG3_GC_BUTTON_A,
                         "Button-1");

    /* if a gamecontroller/joystick is found, use it, else use keyboard */
    jid = 0;
    if (subm_gc != NULL) {
      int *jidf;
      VG3_gamecontroller_getall(wstruct, &jidf);
      if (jidf[0] > 0) { jid = jidf[1]; }  /* use first found one */
      free(jidf);
    }

    /* retrieve ip of network server via multicast/broadcast
     * variables:
     * - "ipsrv" gets server ip
     * - "remhost" gets server name
     */
    if (VG3_inputevent_update(wstruct)) { goto endgame; }
    print_text(wstruct, "Searching for network-server...");
    VG3_window_update(wstruct, 0, 0);
    ipsrv = VG3_nw_mbcast_getip(remhost, sizeof(remhost));
    if (ipsrv == NULL) { fprintf(stderr, "%s\n", VG3_error()); retw = 1; goto endgame; }

    /* show server name and ip */
    if (VG3_inputevent_update(wstruct)) { goto endgame; }
    snprintf(buf, sizeof(buf), "%s: %s", remhost, ipsrv);
    print_text(wstruct, buf);
    VG3_window_update(wstruct, 0, 0);
    sleep(3);

    /* get initialized network struct */
    nwptr = VG3_nw_open(wstruct);

    /* add keys (here just KEYREF_PRESSED) installed into the system menu to network server */
    VG3_keys_nw_addkeys(skeys, nwptr, jid);

    /* clear window and connect to network server */
    if (VG3_inputevent_update(wstruct)) { goto endgame; }
    VG3_draw_clear(wstruct, NULL, VG3_color_brightness(VGAG3_COLOR_PINK, 70));
    VG3_window_update(wstruct, 0, 0);
    clnr = VG3_nw_connect(nwptr, ipsrv, NULL, NULL, 0, &masterbyte);
    if (clnr < 0) { fprintf(stderr, "%s\n", VG3_error()); retw = 1; goto endgame; }
    if (clnr == 0) { goto endgame; }
    if (VG3_inputevent_update(wstruct)) { goto endgame; }
    free(ipsrv);

    /* show own client number */
    snprintf(buf, sizeof(buf), "Connected. client no: %d", clnr);
    print_text(wstruct, buf);
    VG3_window_update(wstruct, 0, 0);
    sleep(3);

    /* master stops multicast/broadcast server */
    if (is_master) { VG3_nw_mbcast_stop(); }

    /* get number of connected clients and show their names
     * variables:
     * - "clmax" gets number of connected clients
     */
    *buf = '\0';
    clmax = VG3_nw_numberofclients(nwptr);
    if (VG3_inputevent_update(wstruct)) { goto endgame; }
    for (cli = 1; cli <= clmax; cli++) {
      const char *name;
      if (VG3_nw_getclientinfo(nwptr, cli, &name)) {
        snprintf(buf + strlen(buf), sizeof(buf) - strlen(buf), "[%d]: %s\n", cli, name);
      }
    }
    print_text(wstruct, buf);
    VG3_window_update(wstruct, 0, 0);
    sleep(3);

    /* game-loop */
    for (;;) {
      if (VG3_nw_update(nwptr, &dowait)) { break; }

      /* exit */
      if (VG3_key_ispressed(wstruct, VGAG3_KEY_Q, VGAG3_IS_PRESSED)) { break; }

      /* call system menu */
      if (VG3_key_ispressed(wstruct, VGAG3_KEY_ESC, VGAG3_IS_NEW_PRESSED)) {
        if (VG3_sysmenu_exec(sysm)) { break; }
      }

      /* for each client get status whether key is pressed or not */
      *buf = '\0';
      for (cli = 1; cli <= clmax; cli++) {
        /* check whether client is still connected */
        if (!VG3_nw_getclientinfo(nwptr, cli, NULL)) { continue; }

        snprintf(buf + strlen(buf), sizeof(buf) - strlen(buf), "[%d]:", cli);

        if (VG3_keys_key_ispressed(skeys, nwptr, cli, -1, KEYREF_PRESSED, VGAG3_IS_PRESSED)) {
          snprintf(buf + strlen(buf), sizeof(buf) - strlen(buf), " is pressed");
        } else {
          snprintf(buf + strlen(buf), sizeof(buf) - strlen(buf), " is not pressed");
        }

        snprintf(buf + strlen(buf), sizeof(buf) - strlen(buf), "\n");
      }

      /* show retrieved status */
      print_text(wstruct, buf);
      VG3_window_update(wstruct, 0, 0);

      if (dowait) { VG3_wait_time(30); }
    }

    /* ending */

    /* close network */
    VG3_nw_close(nwptr);

    /* save key definitions for system menu into file */
    { char *sysm_string_new = VG3_sysmenu_savestring_insert(sysm, sysm_string);
      if ((ffp = fopen("nwkeys.keysave", "w")) != NULL) { fprintf(ffp, "%s", sysm_string_new); fclose(ffp); }
      free(sysm_string_new);
    }

    /* freeing */
    free(sysm_string);
    VG3_keys_free(skeys);
    VG3_sysmenu_free(sysm);

  endgame:
    VG3_window_free(wstruct);

    exit(retw);
  }