WarpPos

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Revision as of 11:45, 5 October 2012 by Kireji Haiku (talk | contribs) (updated from llSetPrimitiveParams([___]); to llSetLinkPrimitiveParamsFast(LINK_ROOT, [___]); to make warping faster (no 200 milisecond delay))
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WarpPos is a method by which the 10m limit on non-physical movement can be avoided, by exploiting a misfeature in llSetPrimitiveParams in which multiple parameters of the same flag type are executed in a single server frame. <lsl> warpPos( vector destinationRootPosition ) {

   //R&D by Keknehv Psaltery, 05/25/2006
   //with a little poking by Strife, and a bit more
   //some more munging by Talarus Luan
   //Final cleanup by Keknehv Psaltery
   //Changed jump value to 411 (4096 ceiling) by Jesse Barnett
   // Compute the number of jumps necessary
   vector currentRootPosition = llGetRootPosition();
   integer jumps = (integer)(llVecDist(destinationRootPosition, currentRootPosition) / 10.0) + 1;
   // Try and avoid stack/heap collisions
   if (jumps > 411)
       jumps = 411;
   // The start for the rules list
   list rules = [ PRIM_POSITION, destinationRootPosition ];
   integer count = 1;
   while ( ( count = count << 1 ) < jumps)
       rules = (rules=[]) + rules + rules;// should tighten memory use.
   llSetLinkPrimitiveParamsFast(LINK_ROOT,
       rules + llList2List( rules, (count - jumps) << 1, count) );
   //Failsafe
   currentRootPosition = llGetRootPosition();
   if ( llVecDist( currentRootPosition, destinationRootPosition ) > .001 )
       while ( --jumps ) 
           llSetLinkPrimitiveParamsFast(LINK_ROOT, [PRIM_POSITION, destinationRootPosition] );

} </lsl>

Quote: warpPos -- llSetPos without the limits ~~ Keknehv Psaltery

A few observations:
Sim crossings are perilous for AVs. Depending on connection speed and whether or not you are connected to the sim (can see it on the mini-map), it may screw up your client. However, it seems like objects, by themselves, can cross great distances. I managed to send an object 4 sims away diagonally. Further testing would help us to understand these things.
...
The average time this function takes to execute is under .2 seconds, which is barely noticeable at all, and can easily be attributed to general lag. A simple optimization for an object with a known destination might be to calculate the list beforehand, and then call llSetPrimitiveParams with that list.
...
a Linden ... response ... go ahead and find a workaround - I'd love to see it, I'm sure it is usefull, but it might not work very well across sim borders