Basic llCastRay script

// Rez a prim and put this script in it contents. Take the prim and attach to HUD center.

list avibtns;
list Targets;
integer lchan;
integer lhandle;
key Owner;
key Target;
integer Trigger;


list order_buttons(list buttons)
{
    return llList2List(buttons, -3, -1) + llList2List(buttons, -6, -4) +
        llList2List(buttons, -9, -7) + llList2List(buttons, -12, -10);
}

Timer()
{
    llSetTimerEvent(0.0);
    llSetTimerEvent(120.0);
}

default
{


state_entry()
{

Owner = llGetOwner();
lchan = -(integer) ( "0x" + (string) llGetKey() ) - 987653;


}


attach(key id)
{

 if(id)
 {
  llRequestPermissions(id, PERMISSION_TRACK_CAMERA);
  llOwnerSay("Focus your camera on an avatar then touch the HUD to target them.");
}

  else
  Trigger = FALSE;

}

run_time_permissions(integer perms)
{

   if(perms & PERMISSION_TRACK_CAMERA )
   {

       Trigger = TRUE;
    }


}


touch_end(integer num)
{

if(llDetectedKey(0) == Owner && Trigger)
{



avibtns = [];


Targets = llCastRay(llGetCameraPos(),llGetCameraPos() + (llRot2Fwd(llGetCameraRot())*15),[ RC_MAX_HITS,10, RC_REJECT_TYPES, RC_REJECT_PHYSICAL | RC_REJECT_NONPHYSICAL | RC_REJECT_LAND  ]);


/// Gets a list of the nearest 10 avatars that collide with ray cast from your line of sight within a max distance of 15 meters.  The line of sight is determined by casting a ray from camera position to a point so many meters away from the camera position's forward rotation. To change the distance of the ray just change the number the camera rotation is multiplied by. 1 = 1 meter.  Restricts collisions to avatars only by rejecting land and object collisions.

     if(llList2String(Targets,0) != "0") // if there are targets nearby
     {
      integer llength= llGetListLength(Targets);




        integer i;

        for(i = 0; i < llength-2; i = i+2)
        {


            avibtns += [llKey2Name(llList2Key(Targets,i))] + [llList2Key(Targets,i)]; // Adds name of avatar + key to a list.


        }



    llListenRemove(lhandle);
    lhandle = llListen(lchan,"",Owner,"");

    Timer();

         llDialog(Owner,"\nSelect the person in your line of sight that you want to target, or click Cancel to cancel.", order_buttons(llList2ListStrided(avibtns,0,-1,2) +["Cancel"]),lchan);
         }

         else
         {

              llDialog(Owner,"\nThere are no targets nearby.", [],lchan);


         }



  }
}






  listen(integer chan, string name, key id, string msg)
{

if(chan == lchan)
{

if(msg != "Cancel")
{
   integer aviidx = llListFindList(avibtns,[msg]); // Finds the name selected in the list.

      if(aviidx !=-1)
      {

         Target = llList2Key(avibtns,aviidx+1);

      }


    llOwnerSay("Target locked on " + llKey2Name(Target) + ".");
    }


    llListenRemove(lhandle);


    }



}

timer()
{

 llSetTimerEvent(0.0);
 llListenRemove(lhandle);


}

}