Aw world attributes send C example 1

This is a simple example of how to do world attribute zones in a world.

#include "Aw.h"
#include "Reason.h"
#include <stdio.h>
#include <stdlib.h>

void handle_avatar_add (void);
void handle_avatar_change (void);

int main(int argc, char *argv[])
{
  int rc;
  
  /* Check command line */
  if (argc < 4)
  {
    printf ("Usage: %s number password world\n", argv[0]);
    return 1;
  }   
  
  /* Initialize Active Worlds API */
  rc = aw_init (AW_BUILD);
  if (rc != RC_SUCCESS)
  {
    printf ("Unable to initialize API (reason %d)\n", rc);
    return 1;
  }
  
  /* Install event handlers */
  aw_event_set (AW_EVENT_AVATAR_ADD, handle_avatar_add);
  aw_event_set (AW_EVENT_AVATAR_CHANGE, handle_avatar_change);
  
  /* Create bot instance */
  rc = aw_create (NULL, 0, NULL);
  if (rc != RC_SUCCESS)
  {
    printf ("Unable to create bot instance (reason %d)\n", rc);
    return 1;
  }
  
  /* Log bot into the universe */
  aw_int_set (AW_LOGIN_OWNER, atoi (argv[1]));
  aw_string_set (AW_LOGIN_PRIVILEGE_PASSWORD, argv[2]);
  aw_string_set (AW_LOGIN_APPLICATION, "aw_world_attributes_send sample application #1");
  aw_string_set (AW_LOGIN_NAME, "MyBot");
  rc = aw_login ();
  if (rc != RC_SUCCESS)
  {
    printf ("Unable to login (reason %d)\n", rc);
    return 1;
  }
  
   /* Use global mode to allow zones anywhere in world */
  aw_bool_set (AW_ENTER_GLOBAL, 1);
  
  /* Enter bot into the world */
  rc = aw_enter (argv[3]);
  if (rc != RC_SUCCESS)
  {
    printf ("Unable to enter world (reason %d)\n", rc);
    return 1;
  }
  
  /* Main event loop */
  while (aw_wait (-1) == RC_SUCCESS);
  
  /* Close everything down */
  aw_destroy ();
  aw_term ();
  
  return 0;
}

/* Array of all sessions, a static array in this example;
 * You are advised to make this a dynamic array, e.g. <map> with stdc++
 * and remove the array entry on world-exit (not shown in this example).
 */
static int zones[100000];
 
int zone_from_cm (int x, int z)
{
  /* zone 1 */
  if (x >= 10000 && x < 20000)    /* 10W to 20W */
    if (z >= 10000 && z < 20000)  /* 10N to 20N */
      return 1;
  
  /* zone 2 */
  if (x >= -20000 && x < -10000)   /* 10E to 20E */
    if (z >= -20000 && z < -10000) /* 10S to 20S */
      return 2;
  
  /* ... zone N */
  
  /* zone 0 means the coordinates do not lie within any of the zones */
  return 0;
}

void handle_avatar_change ()
{
  int session; /* session number of avatar */
  int before;  /* zone before moving */
  int after;   /* zone after moving */
  int rc;
  
  session = aw_int (AW_AVATAR_SESSION);
  
  before = zones[session];
  after = zone_from_cm (aw_int (AW_AVATAR_X), aw_int (AW_AVATAR_Z));
  zones[session] = after;
  
  if (before == after)
  {
    /* avatar is still within the same zone */
    return;
  }
  
  /* send world attributes that differ depending on zone */
  switch (after)
  {
    case 0: /* default zone */
      aw_float_set (AW_WORLD_GRAVITY, 1.0);
      break;
    case 1: /* zone 1 */
      aw_float_set (AW_WORLD_GRAVITY, 0);
      break;
    case 2: /* zone 2 */
      aw_float_set (AW_WORLD_GRAVITY, -1.0);
      break;
    /* ... zone N */
  }
  rc = aw_world_attributes_send (session);
  if (rc != RC_SUCCESS)
    printf ("Unable to send attributes (reason %d)\n", rc);
}

void handle_avatar_add ()
{
  int session; /* session number of avatar */
  
  session = aw_int (AW_AVATAR_SESSION);
  zones[session] = 0; /* default zone */
  
  /* check if avatar has entered outside of the default zone */
  handle_avatar_change();
}