GTA3 car path links bug

[firedihm]

There's a famous bug in GTA3 that involves car pathfinding: AI often ignores vertical distance between path nodes. This was fixed in earlier versions of SP, but only for aggressive drivers—those that follow player—specifically in “Bait” mission. This issue persists for regular drivers, or “cars on rails.”

Video demonstration of the bug. In the video cars driving on underpass can connect to path nodes above the tunnel.

This loop needs to have a pos.z check added for proper path node linking.

// find closest unconnected node
nearestId = -1;
nearestDist = maxdist;
for(k = 0; k < TempListLength; k++){
    dx = tempnodes[k].pos.x - CoorsXFormed.x;
    if(Abs(dx) < nearestDist){
        dy = tempnodes[k].pos.y - CoorsXFormed.y;
        if(Abs(dy) < nearestDist){
            /* ideally, add z pos checking here */
            nearestDist = Max(Abs(dx), Abs(dy));
            nearestId = k;
        }
    }
}