//DOKU
private void TraverseSearch(Point query,
OctreeBox node, NeigbourCollector neighbours)
{
if (node.IsLeaf)
{
foreach (Point p in node.Points)
{
neighbours.AddNeighbour(p);
}
return;
}
// not leaf
foreach (OctreeBox subNode in node.SubBoxes)
{
double curMinSDist = subNode.MinimumSquareDistanceTo(query);
//TODO that shit about the Neighbourlist count
// is really, really crappy!
if (neighbours.BestNeighbours.Count > 0 &&
curMinSDist > neighbours.LargestSquareDistance)
{
continue;
}
TraverseSearch(query, subNode, neighbours);
}
return;
}
//DOKU
public List <Point> ClosestNeighbours(Point query, int amount)
{
NeigbourCollector neighbours = new NeigbourCollector(query, amount);
TraverseSearch(query, RootNode, neighbours);
return(neighbours.BestNeighbours);
}
/// <summary>
/// Recursive search for neighbours.
/// </summary>
/// <param name="query">center of the search</param>
/// <param name="node">current checked node</param>
/// <param name="depth">current recursion depth</param>
/// <param name="neighbours">KDTreeNeighbours-object, collecting results of nm-search</param>
private void NMSearch(Point query,
KDTreeNode node, int depth, NeigbourCollector neighbours)
{
// The NM-search does only look for potential neighbours. The
// final decision if this node is to be returned or not will
// be done by the KDTreeNeighbours-object
// If there is no node, return.
if (node == null)
{
return;
}
// If the node is a leaf, it will always be added to the neighbours-list
if (node.IsLeaf())
{
neighbours.AddNeighbour(node.Point);
return;
}
// locked to 3 axis
int axis = depth % 3;
// One subtree usually lies closer to the query point along the currently
// viewed axis. This one is the close-tree. The other one is the far-tree.
KDTreeNode farSubTree, closeSubTree;
if (query[axis] < node.Point[axis])
{
farSubTree = node.Right;
closeSubTree = node.Left;
}
else
{
farSubTree = node.Left;
closeSubTree = node.Right;
}
// Search the close-tree first
NMSearch(query, closeSubTree, depth + 1, neighbours);
// Since the current point was not sortet out by the
// previous recursion level, it needs to be added to
// the neighbour list.
neighbours.AddNeighbour(node.Point);
// If the current 'boundary' lies closer to the query
// point than the farest approved neighbour so far,
// the other side of the boundary also needs to be
// searched.
if (System.Math.Pow(node.Point[axis] -
query[axis], 2) < neighbours.LargestSquareDistance)
{
NMSearch(query, farSubTree, depth + 1, neighbours);
}
return;
}
/// <summary>
/// Returns the n closest neighbours to a query point.
/// </summary>
/// <param name="query">query point</param>
/// <param name="amount">n, the amount of desired neighbours</param>
/// <returns>The n closest neighbours to query</returns>
public List <Point> FindClosestNeighbours(Point query, int amount)
{
// This method is just a "wrapper". The real search will be
// done by NMSearch().
// This approach was necessary to define and return the
// neighbours list.
NeigbourCollector neighbours = new NeigbourCollector(query, amount);
NMSearch(query, RootNode, 0, neighbours);
return(neighbours.BestNeighbours);
}
