public QuadTreeItem <T>?QueryNearest(RectangleF range, PointF start)
{
var items = Query(range);
if (items == null)
{
return(null);
}
bool hasValue = false;
float lastItemDst = default;
QuadTreeItem <T> lastItem = default;
foreach (var item in items)
{
if (hasValue &&
item.Bounds.SquaredDistanceTo(start).CompareTo(lastItemDst) >= 0)
{
continue;
}
hasValue = true;
lastItem = item;
lastItemDst = item.Bounds.SquaredDistanceTo(start);
}
QuadTreePool <T> .Return(items);
if (!hasValue)
{
return(null);
}
return(lastItem);
}
public void Clear()
{
void RecursiveTreeReturn(QuadTree <T> tree, bool isRoot = false)
{
if (tree.IsDivided)
{
RecursiveTreeReturn(tree.TopLeft);
RecursiveTreeReturn(tree.TopRight);
RecursiveTreeReturn(tree.BottomLeft);
RecursiveTreeReturn(tree.BottomRight);
}
tree.TopLeft = null;
tree.TopRight = null;
tree.BottomLeft = null;
tree.BottomRight = null;
tree.IsDivided = false;
if (!isRoot)
{
QuadTreePool <T> .Return(tree);
}
}
RecursiveTreeReturn(this, isRoot: true);
Items.Clear();
}
public void Resize(RectangleF boundary)
{
Bounds = boundary;
var items = GetItems();
Clear();
foreach (var item in items)
{
Insert(item);
}
QuadTreePool <T> .Return(items);
}
private void Subdivide()
{
float x = Bounds.X;
float y = Bounds.Y;
float w = Bounds.Width / 2f;
float h = Bounds.Height / 2f;
// we cannot allow fuzzyBoundaries for leaf trees as that breaks precision
TopLeft = QuadTreePool <T> .Rent(x, y, w, h, Threshold, AllowOverflow, fuzzyBoundaries : false);
TopRight = QuadTreePool <T> .Rent(x + w, y, w, h, Threshold, AllowOverflow, fuzzyBoundaries : false);
BottomLeft = QuadTreePool <T> .Rent(x, y + h, w, h, Threshold, AllowOverflow, fuzzyBoundaries : false);
BottomRight = QuadTreePool <T> .Rent(x + w, y + h, w, h, Threshold, AllowOverflow, fuzzyBoundaries : false);
IsDivided = true;
}
/// <summary>
/// Returns a list containing every item from this <see cref="QuadTree{T}"/>.
/// </summary>
/// <returns><see cref="ListArray{QuadTreeItem{T}}"/> containing every item.</returns>
public ListArray <QuadTreeItem <T> > GetItems()
{
var items = QuadTreePool <T> .RentItemList();
void AddToList(QuadTree <T> tree)
{
items.AddRange(tree.Items);
if (tree.IsDivided)
{
AddToList(tree.TopLeft);
AddToList(tree.TopRight);
AddToList(tree.BottomLeft);
AddToList(tree.BottomRight);
}
}
AddToList(this);
return(items);
}
public ListArray <QuadTreeItem <T> > Query(RectangleF range)
{
if (!Bounds.Intersects(range))
{
return(null);
}
var result = QuadTreePool <T> .RentItemList();
var items = GetItems();
foreach (var item in items)
{
if (range.Intersects(item.Bounds))
{
result.Add(item);
}
}
QuadTreePool <T> .Return(items);
return(result);
}
