EDIT: Just saw your most recent post and it doesn't look like this is what you wanted, but you can use this as a base to do what you want (it would take a lot of time to get it perfect, and a lot of processing).
I threw this plugin together going off of some of the information Orangutanz posted.
I didn't do any testing to check if it is correct or not, I'll leave that up to you.
Note: Changing the GRID_SIZE will change how accurate it is, but in return it will change how fast it processes.
Note 2: Yes it's sloppy... feel free to optimize it.
How to use:
1) Compile plugin.
2) Add plugin to server.
3) Type "mapsize" in server console.
4) Read the output (in the server console).
Not sure if this is what you wanted or not, I'm tired :)
#include <amxmodx>
#include <fakemeta>
#define PLUGIN "Map Size"
#define VERSION "1.0"
#define AUTHOR "hlstriker"
#define MAP_MIN -4096
#define MAP_MAX 4096
// Smallest size is most accurate, BUT takes longer to process
//#define GRID_SIZE 1
//#define GRID_SIZE 2
#define GRID_SIZE 4
//#define GRID_SIZE 8
//#define GRID_SIZE 16
//#define GRID_SIZE 32
new Float:g_flOrigin[3];
new g_iMin_X, g_iMax_X;
new g_iMin_Y = -5000, g_iMax_Y;
new g_iMin_Z, g_iMax_Z;
public plugin_init()
{
register_plugin(PLUGIN, VERSION, AUTHOR);
register_srvcmd("mapsize", "get_map_size");
}
public get_map_size()
{
new iCurrentY = MAP_MIN;
new iTemp;
server_print("Gathering map size information, please be patient.");
while(iCurrentY <= MAP_MAX)
{
// Get minimum X origin
iTemp = check_min_x(iCurrentY);
if(iTemp < g_iMin_X)
g_iMin_X = iTemp;
// Get maximum X origin
iTemp = check_max_x(iCurrentY);
if(iTemp > g_iMax_X)
g_iMax_X = iTemp;
// Get minimum Z origin
iTemp = check_min_z(iCurrentY);
if(iTemp < g_iMin_Z)
g_iMin_Z = iTemp;
// Get maximum Z origin
iTemp = check_max_z(iCurrentY);
if(iTemp > g_iMax_Z)
g_iMax_Z = iTemp;
iCurrentY += GRID_SIZE;
}
server_print("[Min X = %i] [Max X = %i]", g_iMin_X, g_iMax_X);
server_print("[Min Y = %i] [Max Y = %i]", g_iMin_Y, g_iMax_Y);
server_print("[Min Z = %i] [Max Z = %i]", g_iMin_Z, g_iMax_Z);
}
// Start X coords
check_min_x(const iCurrentY)
{
// Return the minimum X origin that isn't empty
static iContents, iCurrentX, bool:mHit, bool:mEmpty;
mEmpty = false;
mHit = false;
iContents = 0;
iCurrentX = MAP_MIN;
g_flOrigin[1] = 0.0; // Z
g_flOrigin[2] = float(iCurrentY); // Y
while(iCurrentX <= MAP_MAX)
{
g_flOrigin[0] = float(iCurrentX); // X
iContents = engfunc(EngFunc_PointContents, g_flOrigin);
if(iContents != -1 && mEmpty)
{
mHit = true;
break;
}
else if(iContents == -1)
mEmpty = true;
iCurrentX += GRID_SIZE;
}
// Check the Y origin
if(mHit)
{
if(g_iMin_Y < MAP_MIN)
g_iMin_Y = iCurrentY;
else
g_iMax_Y = iCurrentY;
}
return iCurrentX;
}
check_max_x(const iCurrentY)
{
// Return the maximum X origin that isn't empty
static iContents, iCurrentX, bool:mHit, bool:mEmpty;
mEmpty = false;
mHit = false;
iContents = 0;
iCurrentX = MAP_MAX;
g_flOrigin[1] = 0.0; // Z
g_flOrigin[2] = float(iCurrentY); // Y
while(iCurrentX >= MAP_MIN)
{
g_flOrigin[0] = float(iCurrentX); // X
iContents = engfunc(EngFunc_PointContents, g_flOrigin);
if(iContents != -1 && mEmpty)
{
mHit = true;
break;
}
else if(iContents == -1)
mEmpty = true;
iCurrentX -= GRID_SIZE;
}
// Check the Y origin
if(mHit)
{
if(g_iMin_Y < MAP_MIN)
g_iMin_Y = iCurrentY;
else
g_iMax_Y = iCurrentY;
}
return iCurrentX;
}
// Start Z coords
check_min_z(const iCurrentY)
{
// Return the minimum Z origin that isn't empty
static iContents, iCurrentZ, bool:mHit, bool:mEmpty;
mEmpty = false;
mHit = false;
iContents = 0;
iCurrentZ = MAP_MIN;
g_flOrigin[0] = 0.0; // X
g_flOrigin[2] = float(iCurrentY); // Y
while(iCurrentZ <= MAP_MAX)
{
g_flOrigin[1] = float(iCurrentZ); // Z
iContents = engfunc(EngFunc_PointContents, g_flOrigin);
if(iContents != -1 && mEmpty)
{
mHit = true;
break;
}
else if(iContents == -1)
mEmpty = true;
iCurrentZ += GRID_SIZE;
}
// Check the Y origin
if(mHit)
{
if(g_iMin_Y < MAP_MIN)
g_iMin_Y = iCurrentY;
else
g_iMax_Y = iCurrentY;
}
return iCurrentZ;
}
check_max_z(const iCurrentY)
{
// Return the maximum Z origin that isn't empty
static iContents, iCurrentZ, bool:mHit, bool:mEmpty;
mEmpty = false;
mHit = false;
iContents = 0;
iCurrentZ = MAP_MAX;
g_flOrigin[0] = 0.0; // X
g_flOrigin[2] = float(iCurrentY); // Y
while(iCurrentZ >= MAP_MIN)
{
g_flOrigin[1] = float(iCurrentZ); // Z
iContents = engfunc(EngFunc_PointContents, g_flOrigin);
if(iContents != -1 && mEmpty)
{
mHit = true;
break;
}
else if(iContents == -1)
mEmpty = true;
iCurrentZ -= GRID_SIZE;
}
// Check the Y origin
if(mHit)
{
if(g_iMin_Y < MAP_MIN)
g_iMin_Y = iCurrentY;
else
g_iMax_Y = iCurrentY;
}
return iCurrentZ;
}