/// <summary>
/// Handles item movement
/// </summary>
/// <param name="item">The item that moved</param>
public void ItemMove(QuadTreePositionItem <T> item)
{
// Find the item
if (Items.Contains(item))
{
int i = Items.IndexOf(item);
// Try to push the item down to the child
if (!PushItemDown(i))
{
// otherwise, if not root, push up
if (ParentNode != null)
{
PushItemUp(i);
}
else if (!ContainsRect(item.Rect))
{
WorldResize(new FRect(
Vector2.Min(Rect.TopLeft, item.Rect.TopLeft) * 2,
Vector2.Max(Rect.BottomRight, item.Rect.BottomRight) * 2));
}
}
}
else
{
// this node doesn't contain that item, stop notifying it about it
item.Move -= new QuadTreePositionItem <T> .MoveHandler(ItemMove);
}
}
/// <summary>
/// Push an item up to this node's parent
/// </summary>
/// <param name="i">The index of the item to push up</param>
public void PushItemUp(int i)
{
QuadTreePositionItem <T> m = Items[i];
RemoveItem(i);
ParentNode.Insert(m);
}
/// <summary>
/// Inserts an item into one of this node's children
/// </summary>
/// <param name="item">The item to insert in a child</param>
/// <returns>Whether or not the insert succeeded</returns>
protected bool InsertInChild(QuadTreePositionItem <T> item)
{
if (!IsPartitioned)
{
return(false);
}
if (TopLeftNode.ContainsRect(item.Rect))
{
TopLeftNode.Insert(item);
}
else if (TopRightNode.ContainsRect(item.Rect))
{
TopRightNode.Insert(item);
}
else if (BottomLeftNode.ContainsRect(item.Rect))
{
BottomLeftNode.Insert(item);
}
else if (BottomRightNode.ContainsRect(item.Rect))
{
BottomRightNode.Insert(item);
}
else
{
return(false); // insert in child failed
}
return(true);
}
/// <summary>
/// Removes an item from this node
/// </summary>
/// <param name="item">The item to remove</param>
public void RemoveItem(QuadTreePositionItem <T> item)
{
// Find and remove the item
if (Items.Contains(item))
{
item.Move -= new QuadTreePositionItem <T> .MoveHandler(ItemMove);
item.Destroy -= new QuadTreePositionItem <T> .DestroyHandler(ItemDestroy);
Items.Remove(item);
}
}
/// <summary>
/// Inserts an item into the QuadTree
/// </summary>
/// <param name="item">The item to insert</param>
/// <remarks>Checks to see if the world needs resizing and does so if needed</remarks>
public void Insert(QuadTreePositionItem <T> item)
{
// check if the world needs resizing
if (!headNode.ContainsRect(item.Rect))
{
Resize(new FRect(
Vector2.Min(headNode.Rect.TopLeft, item.Rect.TopLeft) * 2,
Vector2.Max(headNode.Rect.BottomRight, item.Rect.BottomRight) * 2));
}
headNode.Insert(item);
}
/// <summary>
/// Inserts an item into the QuadTree
/// </summary>
/// <param name="parent">The parent of the new position item</param>
/// <param name="position">The position of the new position item</param>
/// <param name="size">The size of the new position item</param>
/// <returns>A new position item</returns>
/// <remarks>Checks to see if the world needs resizing and does so if needed</remarks>
public QuadTreePositionItem <T> Insert(T parent, Vector2 position, Vector2 size)
{
QuadTreePositionItem <T> item = new QuadTreePositionItem <T>(parent, position, size);
// check if the world needs resizing
if (!headNode.ContainsRect(item.Rect))
{
Resize(new FRect(
Vector2.Min(headNode.Rect.TopLeft, item.Rect.TopLeft) * 2,
Vector2.Max(headNode.Rect.BottomRight, item.Rect.BottomRight) * 2));
}
headNode.Insert(item);
return(item);
}
/// <summary>
/// Insert an item in this node
/// </summary>
/// <param name="item">The item to insert</param>
public void Insert(QuadTreePositionItem <T> item)
{
// If partitioned, try to find child node to add to
if (!InsertInChild(item))
{
item.Destroy += new QuadTreePositionItem <T> .DestroyHandler(ItemDestroy);
item.Move += new QuadTreePositionItem <T> .MoveHandler(ItemMove);
Items.Add(item);
// Check if this node needs to be partitioned
if (!IsPartitioned && Items.Count >= MaxItems)
{
Partition();
}
}
}
/// <summary>
/// Finds the node containing a specified item
/// </summary>
/// <param name="Item">The item to find</param>
/// <returns>The node containing the item</returns>
public QuadTreeNode <T> FindItemNode(QuadTreePositionItem <T> Item)
{
if (Items.Contains(Item))
{
return(this);
}
else if (IsPartitioned)
{
QuadTreeNode <T> n = null;
// Check the nodes that could contain the item
if (TopLeftNode.ContainsRect(Item.Rect))
{
n = TopLeftNode.FindItemNode(Item);
}
if (n == null &&
TopRightNode.ContainsRect(Item.Rect))
{
n = TopRightNode.FindItemNode(Item);
}
if (n == null &&
BottomLeftNode.ContainsRect(Item.Rect))
{
n = BottomLeftNode.FindItemNode(Item);
}
if (n == null &&
BottomRightNode.ContainsRect(Item.Rect))
{
n = BottomRightNode.FindItemNode(Item);
}
return(n);
}
else
{
return(null);
}
}
/// <summary>
/// Handles item destruction
/// </summary>
/// <param name="item">The item that is being destroyed</param>
public void ItemDestroy(QuadTreePositionItem <T> item)
{
RemoveItem(item);
}