private void Relocate(QuadTreeObject <T> item)
{
// Are we still inside our parent?
if (QuadRect.Contains(item.Data.Rect))
{
// Good, have we moved inside any of our children?
if (childTL != null)
{
QuadTreeNode <T> dest = GetDestinationTree(item);
if (item.Owner != dest)
{
// Delete the item from this quad and add it to our child
// Note: Do NOT clean during this call, it can potentially delete our destination quad
QuadTreeNode <T> formerOwner = item.Owner;
Delete(item, false);
dest.Insert(item);
// Clean up ourselves
formerOwner.CleanUpwards();
}
}
}
else
{
// We don't fit here anymore, move up, if we can
if (parent != null)
{
parent.Relocate(item);
}
}
}
public void Add(T item)
{
QuadTreeObject <T> wrappedObject = new QuadTreeObject <T>(item);
wrappedDictionary.Add(item, wrappedObject);
quadTreeRoot.Insert(wrappedObject);
}
internal void Insert(QuadTreeObject <T> item)
{
// If this quad doesn't contain the items rectangle, do nothing, unless we are the root
if (!rect.Contains(item.Data.Rect))
{
System.Diagnostics.Debug.Assert(parent == null, "We are not the root, and this object doesn't fit here. How did we get here?");
if (parent == null)
{
// This object is outside of the QuadTree bounds, we should add it at the root level
Add(item);
}
else
{
return;
}
}
if (objects == null ||
(childTL == null && objects.Count + 1 <= maxObjectsPerNode))
{
// If there's room to add the object, just add it
Add(item);
}
else
{
// No quads, create them and bump objects down where appropriate
if (childTL == null)
{
Subdivide();
}
// Find out which tree this object should go in and add it there
QuadTreeNode <T> destTree = GetDestinationTree(item);
if (destTree == this)
{
Add(item);
}
else
{
destTree.Insert(item);
}
}
}
private void Subdivide()
{
Point size = new Point(rect.Width / 2, rect.Height / 2);
Point mid = new Point(rect.X + size.X, rect.Y + size.Y);
childTL = new QuadTreeNode <T>(this, new Rectangle(rect.Left, rect.Top, size.X, size.Y));
childTR = new QuadTreeNode <T>(this, new Rectangle(mid.X, rect.Top, size.X, size.Y));
childBL = new QuadTreeNode <T>(this, new Rectangle(rect.Left, mid.Y, size.X, size.Y));
childBR = new QuadTreeNode <T>(this, new Rectangle(mid.X, mid.Y, size.X, size.Y));
for (int i = 0; i < objects.Count; i++)
{
QuadTreeNode <T> destTree = GetDestinationTree(objects[i]);
if (destTree != this)
{
destTree.Insert(objects[i]);
Remove(objects[i]);
i--;
}
}
}
