/** Recursively determines the distance the beginning (lower end) of the quads
* have from the start of the track.
* \param node The node index for which to set the distance from start.
* \param new_distance The new distance for the specified graph node.
*/
void QuadGraph::computeDistanceFromStart(unsigned int node, float new_distance)
{
GraphNode *gn = m_all_nodes[node];
float current_distance = gn->getDistanceFromStart();
// If this node already has a distance defined, check if the new distance
// is longer, and if so adjust all following nodes. Without this the
// length of the track (as taken by the distance from start of the last
// node) could be smaller than some of the paths. This can result in
// incorrect results for the arrival time estimation of the AI karts.
// See trac #354 for details.
// Then there is no need to test/adjust any more nodes.
if(current_distance>=0)
{
if(current_distance<new_distance)
{
float delta = new_distance - current_distance;
updateDistancesForAllSuccessors(gn->getQuadIndex(), delta, 0);
}
return;
}
// Otherwise this node has no distance defined yet. Set the new
// distance, and recursively update all following nodes.
gn->setDistanceFromStart(new_distance);
for(unsigned int i=0; i<gn->getNumberOfSuccessors(); i++)
{
GraphNode *gn_next = m_all_nodes[gn->getSuccessor(i)];
// The start node (only node with distance 0) is reached again,
// recursion can stop now
if(gn_next->getDistanceFromStart()==0)
continue;
computeDistanceFromStart(gn_next->getQuadIndex(),
new_distance + gn->getDistanceToSuccessor(i));
} // for i
} // computeDistanceFromStart
