Z&A As the Crow Flies (Measure points on a sim)

Z&A As the Crow Flies.lsl

//////////////////////////////////////////////////////////////////////
// Z&A As the Crow Flies -- Find the distance between two points.
// By Antony Fairport
//
// Rez one or more prims around a place where you want to know how
// far away they are. Name each prim to something that will mean
// something to you. Now drop this script in each of them. Finally,
// touch the prim that you consider to be the point from which you
// want to measure.
//
// This is handy for things like ensuring that your hunt objects
// are within a specific distance of your sign or landing point if
// you're taking part in a hunt with a rule about how far an object
// can be from where hunters land.

//////////////////////////////////////////////////////////////////////
// Globals.
integer g_iChannel;
integer g_iListen;

//////////////////////////////////////////////////////////////////////
// Default state.
default
{
    //////////////////////////////////////////////////////////////////
    // Configure the script.
    state_entry()
    {
        // Create the channel based on the owner's UUID.
        g_iChannel = ( -1 * (integer) ( "0x" + llGetSubString( (string) llGetOwner(), -5, -1 ) ) );
        
        // Offset the channel a little so we don't obviously clash with anything else
        // that has the same idea. Not really needed but... meh, why not, eh?
        g_iChannel += 23;
        
        // Listen for a call.
        g_iListen = llListen( g_iChannel, "", NULL_KEY, "" );
    }
    
    //////////////////////////////////////////////////////////////////
    // On touch, send out the information for this prim.
    touch_start( integer total_number )
    {
        llRegionSay( g_iChannel, "AsTheCrowFlys|" + ( (string) llGetOwner() ) + "|" + ( (string) llGetPos() ) + "|" + llGetObjectName() );
    }

    //////////////////////////////////////////////////////////////////
    // React to a message coming in on a listen event.
    listen( integer channel, string name, key id, string message )
    {
        // If it's on the right channel...
        if ( channel == g_iChannel )
        {
            // Split the message up
            list lMessage = llParseString2List( message, [ "|" ], [] );

            // Is it a ping from another AtCF object?
            if ( llList2String( lMessage, 0 ) == "AsTheCrowFlys" )
            {            
                // From the owner?
                if ( llList2String( lMessage, 1 ) == ( (string) llGetOwner() ) )
                {
                    // Get the information we need about the other object.
                    vector vPos      = (vector) llList2String( lMessage, 2 );
                    string sName     = llList2String( lMessage, 3 );
                    float  nDistance = llVecDist( llGetPos(), vPos );
                    
                    // Send a message to the owner, telling them how far away it is.
                    llInstantMessage( llGetOwner(), "Distance to object '" + sName + "': " + ( (string) nDistance ) + "m" );
                }
            }
        }
    }

    //////////////////////////////////////////////////////////////////
    // Look for a change event.
    changed( integer change )
    {
        // If the owner has changed...
        if ( change & CHANGED_OWNER )
        {
            // ...do a reset.
            llResetScript();
        }
    }
}