User:Strife Onizuka/UpdateLinkSitTarget

<lsl>//Sets / Updates the sit target moving the avatar on it if necessary. UpdateLinkSitTarget(integer link, vector pos, rotation rot) {//Using this while the object is moving may give unpredictable results.

   llLinkSitTarget(link, pos, rot);//Set the sit target
   key user = llAvatarOnLinkSitTarget(link);
   if(user)//true if there is a user seated on the sittarget, if so update their position
   {
       vector size = llGetAgentSize(user);
       if(size)//This tests to make sure the user really exists.
       {
           integer linkNum = llGetNumberOfPrims();
           do{
               if(user == llGetLinkKey( linkNum ))//just checking to make sure the index is valid.
               {
                   //We need to make the position and rotation local to the current prim
                   list local;
                   if(llGetLinkKey(link) != llGetLinkKey(1))//only need the local rot if it's not the root.
                       local = llGetLinkPrimitiveParams(link, [PRIM_POS_LOCAL, PRIM_ROT_LOCAL]);
                   pos.z += 0.4;
                   llSetLinkPrimitiveParamsFast(linkNum, [
                           PRIM_POS_LOCAL, ((pos - (llRot2Up(rot) * size.z * 0.02638)) * llList2Rot(local, 1)) + llList2Vector(local, 0),
                           PRIM_ROT_LOCAL, rot * llList2Rot(local, 1)
                       ]);
                   jump end;//cheaper but a tad slower then return
               }
           }while( --linkNum );
       }
       else
       {//It is rare that the sit target will bork but it does happen, this can help to fix it.
           llUnSit(user);
       }
   }
   @end;

}//Written by Strife Onizuka, size adjustment provided by Escort DeFarge</lsl> <lsl>list GetSitTarget(integer prim, key av) {//WARNING: llGetObjectDetails can introduce an error that goes as far as the 5th decimal place!

//This is highly unlikely to be ever noticed unless compounded over time.
//Do not use while moving (like in a moving vehicle)!!!
   vector tp = llGetAgentSize(av);
   if(tp)
   {
       list details = [OBJECT_POS, OBJECT_ROT];
       integer linkNum = llGetNumberOfPrims();
       do {
           if(av == llGetLinkKey(linkNum)) {
               details = llGetLinkPrimitiveParams(link, [PRIM_POS_LOCAL, PRIM_ROT_LOCAL]);
               if(llGetLinkKey(prim) != llGetLinkKey(1))
                   details += llGetLinkPrimitiveParams(prim, [PRIM_POS_LOCAL, PRIM_ROT_LOCAL]);
               jump next;
           }
       } while( --linkNum );
       details = llGetObjectDetails(av, details) + llGetObjectDetails(llGetLinkKey(prim), details);
       @next;
       rotation f = llList2Rot(details, 1);
       rotation r = llList2Rot(details, 3) / f;
       return [((llList2Vector(details, 2) - llList2Vector(details, 0)) / f) + (llRot2Up(r) * tp.z * 0.02638) - <0.0, 0.0, 0.4>, r];
   }
   return [];

}//Written by Strife Onizuka</lsl>