private Int64 GetChildCode(LinearNode <T> node, Int32 direction)
{
Int64 childCode = node.Code;
childCode += Convert.ToInt64(Math.Pow(4, _maxLevel - node.Region.Level - 1)) * direction;
return(childCode);
}
private List <LinearNode <T> > CalculateLeafProperties()
{
// source: Aizawa, K. et al.: Constant Time Neighbor Finding in Quadtrees, ISCCSP 2008.
_q = new List <LinearNode <T> >();
LinearNode <T> node = new LinearNode <T>(_root, 0);
_q.Add(node);
LinearNode <T> firstGrey = GetFirstGrey(_q);
while (firstGrey != null)
{
SetNeighbourLevels(firstGrey);
_q.Remove(firstGrey);
LinearNode <T>[] children = new LinearNode <T> [4];
children[0] = CreateChildNode(firstGrey, 0);
children[1] = CreateChildNode(firstGrey, 1);
children[2] = CreateChildNode(firstGrey, 2);
children[3] = CreateChildNode(firstGrey, 3);
SetChildNeighbourLevels(firstGrey, children);
_q.InsertRange(0, children);
firstGrey = GetFirstGrey(_q);
}
return(_q);
}
/// <summary>
/// Gets the neighbor of the given node in the given direction.
/// </summary>
/// <param name="node">The node.</param>
/// <param name="d">The direction<./param>
/// <returns>The neighbor, or <c>null</c> if there is no neighbor in the given direction.</returns>
public LinearNode <T> GetNeighbor(LinearNode <T> node, Direction d)
{
// source: Aizawa, K. et al.: Constant Time Neighbor Finding in Quadtrees, ISCCSP 2008.
Int32?dd = null;
long dnq = 0;
switch (d)
{
case Direction.North:
dd = node.North;
dnq = _dn;
break;
case Direction.South:
dd = node.South;
dnq = _ds;
break;
case Direction.East:
dd = node.East;
dnq = _de;
break;
case Direction.West:
dd = node.West;
dnq = _dw;
break;
}
if (dd.HasValue)
{
Int64 mq;
Int64 nq = node.Code;
Int32 l = node.Region.Level;
if (dd < 0)
{
mq = Add(((nq >> 2 * (_maxLevel - l - dd.Value)) << 2 * (_maxLevel - l - dd.Value)), dnq << (2 * (_maxLevel - l - dd.Value)));
}
else
{
mq = Add(nq, dnq << (2 * (_maxLevel - l)));
}
//
LinearNode <T> result = GetNode(mq, _q);
// Fix the algorithm
if (dd > 0 && (d == Direction.South || d == Direction.West))
{
return(NodeOf(GetMostNorthEastRecursive(result.Region.Parent)));
}
return(result);
}
else
{
return(null);
}
}
private void SetNeighbourLevels(LinearNode <T> firstGrey)
{
Int32 l = firstGrey.Region.Level;
// EAST
Int64 id = Add(firstGrey.Code, (_de << (2 * (_maxLevel - l))));
LinearNode <T> node = GetNode(id, _q);
if (node != null)
{
LinearNode <T> n = node;
if (node.Region.Level == l && node.West != null)
{
n.West = node.West + 1;
}
}
// NORTH
id = Add(firstGrey.Code, (_dn << (2 * (_maxLevel - l))));
node = GetNode(id, _q);
if (node != null)
{
LinearNode <T> n = node;
if (node.Region.Level == l && node.South != null)
{
n.South = node.South + 1;
}
}
// WEST
id = Add(firstGrey.Code, (_dw << (2 * (_maxLevel - l))));
node = GetNode(id, _q);
if (node != null)
{
LinearNode <T> n = node;
if (node.Region.Level == l && node.East != null)
{
n.East = node.East + 1;
}
}
// SOUTH
id = Add(firstGrey.Code, (_ds << (2 * (_maxLevel - l))));
node = GetNode(id, _q);
if (node != null)
{
LinearNode <T> n = node;
if (node.Region.Level == l && node.North != null)
{
n.North = node.North + 1;
}
}
}
private LinearNode <T> CreateChildNode(LinearNode <T> parent, Int32 p)
{
return(new LinearNode <T>(parent.Region.Childs[p], GetChildCode(parent, p)));
}
private void SetChildNeighbourLevels(LinearNode <T> parent, LinearNode <T>[] children)
{
LinearNode <T> neighbor;
Int32 l = parent.Region.Level + 1;
children[0].East = 0;
children[0].North = 0;
if (parent.West != null)
{
children[0].West = (parent.West - 1);
neighbor = GetNode(Add(children[0].Code, _dw << (2 * (_maxLevel - l))), _q);
if (neighbor != null && neighbor.Region.Level == l)
{
LinearNode <T> n = neighbor;
n.East = n.East + 1;
}
}
if (parent.South != null)
{
children[0].South = parent.South - 1;
neighbor = GetNode(Add(children[0].Code, _ds << (2 * (_maxLevel - l))), _q);
if (neighbor != null && neighbor.Region.Level == l)
{
LinearNode <T> n = neighbor;
n.North = n.North + 1;
}
}
children[1].North = 0;
children[1].West = 0;
if (parent.East != null)
{
children[1].East = parent.East - 1;
neighbor = GetNode(Add(children[1].Code, _de << (2 * (_maxLevel - l))), _q);
if (neighbor != null && neighbor.Region.Level == l)
{
LinearNode <T> n = neighbor;
n.West = n.West + 1;
}
}
if (parent.South != null)
{
children[1].South = parent.South - 1;
neighbor = GetNode(Add(children[1].Code, _ds << (2 * (_maxLevel - l))), _q);
if (neighbor != null && neighbor.Region.Level == l)
{
LinearNode <T> n = neighbor;
n.North = n.North + 1;
}
}
children[2].South = 0;
children[2].East = 0;
if (parent.North != null)
{
children[2].North = parent.North - 1;
neighbor = GetNode(Add(children[2].Code, _dn << (2 * (_maxLevel - l))), _q);
if (neighbor != null && neighbor.Region.Level == l)
{
LinearNode <T> n = neighbor;
n.South = n.South + 1;
}
}
if (parent.West != null)
{
children[2].West = parent.West - 1;
neighbor = GetNode(Add(children[2].Code, _dw << (2 * (_maxLevel - l))), _q);
if (neighbor != null && neighbor.Region.Level == l)
{
LinearNode <T> n = neighbor;
n.East = n.East + 1;
}
}
children[3].South = 0;
children[3].West = 0;
if (parent.North != null)
{
children[3].North = parent.North - 1;
neighbor = GetNode(Add(children[3].Code, _dn << (2 * (_maxLevel - l))), _q);
if (neighbor != null && neighbor.Region.Level == l)
{
LinearNode <T> n = neighbor;
n.South = n.South + 1;
}
}
if (parent.East != null)
{
children[3].East = parent.East - 1;
neighbor = GetNode(Add(children[3].Code, _de << (2 * (_maxLevel - l))), _q);
if (neighbor != null && neighbor.Region.Level == l)
{
LinearNode <T> n = neighbor;
n.West = n.West + 1;
}
}
}
