/// <summary>
/// Get list of nodes that intersect the given bounds.
/// </summary>
/// <param name="bounds">The bounds to test</param>
/// <returns>The list of nodes intersecting the given bounds</returns>
IEnumerable <QuadNode> GetNodes(Rect bounds)
{
List <QuadNode> result = new List <QuadNode>();
if (_root != null)
{
_root.GetIntersectingNodes(result, bounds);
}
return(result);
}
/// <summary>
/// Rebuild all the Quadrants according to the current QuadTree Bounds.
/// </summary>
private void ReIndex()
{
Quadrant oldRoot = this.root;
this.root = new Quadrant(this.realExtent);
if (oldRoot != null)
{
foreach (var node in oldRoot.GetIntersectingNodes(this.realExtent))
{
// Todo: It would be more efficient if we added a code path that allowed reuse of the QuadNode wrappers.
Insert(node.Item1.Node, node.Item1.Bounds, node.Item1.Priority);
}
}
}
/// <summary>
/// Returns all nodes in this quadrant that intersect the given bounds.
/// The nodes are returned in pretty much random order as far as the caller is concerned.
/// </summary>
/// <param name="nodes">List of nodes found in the given bounds</param>
/// <param name="bounds">The bounds that contains the nodes you want returned</param>
internal void GetIntersectingNodes(List <QuadNode> nodes, Rect bounds)
{
if (bounds.IsEmpty)
{
return;
}
double w = _bounds.Width / 2;
double h = _bounds.Height / 2;
// assumption that the Rect struct is almost as fast as doing the operations
// manually since Rect is a value type.
Rect topLeft = new Rect(_bounds.Left, _bounds.Top, w, h);
Rect topRight = new Rect(_bounds.Left + w, _bounds.Top, w, h);
Rect bottomLeft = new Rect(_bounds.Left, _bounds.Top + h, w, h);
Rect bottomRight = new Rect(_bounds.Left + w, _bounds.Top + h, w, h);
// See if any child quadrants completely contain this node.
if (topLeft.IntersectsWith(bounds) && _topLeft != null)
{
_topLeft.GetIntersectingNodes(nodes, bounds);
}
if (topRight.IntersectsWith(bounds) && _topRight != null)
{
_topRight.GetIntersectingNodes(nodes, bounds);
}
if (bottomLeft.IntersectsWith(bounds) && _bottomLeft != null)
{
_bottomLeft.GetIntersectingNodes(nodes, bounds);
}
if (bottomRight.IntersectsWith(bounds) && _bottomRight != null)
{
_bottomRight.GetIntersectingNodes(nodes, bounds);
}
GetIntersectingNodes(_nodes, nodes, bounds);
}
