/// <summary>
/// Walk the given linked list and test each node against the given bounds/
/// </summary>
/// <param name="last">The last node in the circularly linked list.</param>
/// <param name="bounds">Bounds to test</param>
/// <returns>Return true if a node in the list intersects the bounds</returns>
static Boolean HasIntersectingNodes(QuadNode <T> last, Rect bounds)
{
if (last != null)
{
QuadNode <T> n = last;
do
{
n = n.Next; // first node.
if (n.Bounds.IntersectsWith(bounds))
{
return(true);
}
} while (n != last);
}
return(false);
}
/// <summary>
/// Insert the given node
/// </summary>
/// <param name="node">The node </param>
/// <param name="bounds">The bounds of that node</param>
/// <returns></returns>
internal Quadrant <T> Insert(T node, Rect bounds)
{
Debug.Assert(bounds.Width != 0 && bounds.Height != 0);
if (bounds.Width == 0 || bounds.Height == 0)
{
// todo: localize
throw new ArgumentException("Bounds of quadrant cannot be zero width or height");
}
Double w = Bounds.Width / 2;
if (w == 0)
{
w = 1;
}
Double h = Bounds.Height / 2;
if (h == 0)
{
h = 1;
}
// 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);
Quadrant <T> child = null;
// See if any child quadrants completely contain this node.
if (topLeft.Contains(bounds))
{
if (TopLeft == null)
{
TopLeft = new Quadrant <T>(this, topLeft);
}
child = TopLeft;
}
else if (topRight.Contains(bounds))
{
if (TopRight == null)
{
TopRight = new Quadrant <T>(this, topRight);
}
child = TopRight;
}
else if (bottomLeft.Contains(bounds))
{
if (BottomLeft == null)
{
BottomLeft = new Quadrant <T>(this, bottomLeft);
}
child = BottomLeft;
}
else if (bottomRight.Contains(bounds))
{
if (BottomRight == null)
{
BottomRight = new Quadrant <T>(this, bottomRight);
}
child = BottomRight;
}
if (child != null)
{
return(child.Insert(node, bounds));
}
else
{
QuadNode <T> n = new QuadNode <T>(node, bounds);
if (Nodes == null)
{
n.Next = n;
}
else
{
// link up in circular link list.
QuadNode <T> x = Nodes;
n.Next = x.Next;
x.Next = n;
}
Nodes = n;
return(this);
}
}
