private OctreeNode <T> ResizeAndAdd(OctreeItem <T> octreeItem)
{
OctreeNode <T> oldRoot = this;
Vector3 oldRootCenter = Bounds.GetCenter();
Vector3 oldRootHalfExtents = Bounds.GetDimensions() * 0.5f;
Vector3 expandDirection = Vector3.Normalize(octreeItem.Bounds.GetCenter() - oldRootCenter);
Vector3 newCenter = oldRootCenter;
if (expandDirection.X >= 0) // oldRoot = Left
{
newCenter.X += oldRootHalfExtents.X;
}
else
{
newCenter.X -= oldRootHalfExtents.X;
}
if (expandDirection.Y >= 0) // oldRoot = Bottom
{
newCenter.Y += oldRootHalfExtents.Y;
}
else
{
newCenter.Y -= oldRootHalfExtents.Y;
}
if (expandDirection.Z >= 0) // oldRoot = Far
{
newCenter.Z += oldRootHalfExtents.Z;
}
else
{
newCenter.Z -= oldRootHalfExtents.Z;
}
BoundingBox newRootBounds = new BoundingBox(newCenter - oldRootHalfExtents * 2f, newCenter + oldRootHalfExtents * 2f);
OctreeNode <T> newRoot = _nodeCache.GetNode(ref newRootBounds);
OctreeNode <T> fittingNode = newRoot.SplitChildren(ref octreeItem.Bounds, oldRoot);
if (fittingNode != null)
{
bool succeeded = fittingNode.CoreAddItem(octreeItem);
Debug.Assert(succeeded, "Octree node returned from SplitChildren must fit the item given to it.");
return(newRoot);
}
else
{
return(newRoot.CoreAddRootItem(octreeItem));
}
}
private bool CoreAddItem(OctreeItem <T> item)
{
if (Bounds.Contains(ref item.Bounds) != ContainmentType.Contains)
{
return(false);
}
if (_items.Count >= MaxChildren && Children.Length == 0)
{
OctreeNode <T> newNode = SplitChildren(ref item.Bounds, null);
if (newNode != null)
{
bool succeeded = newNode.CoreAddItem(item);
Debug.Assert(succeeded, "Octree node returned from SplitChildren must fit the item given to it.");
return(true);
}
}
else if (Children.Length > 0)
{
foreach (var child in Children)
{
if (child.CoreAddItem(item))
{
return(true);
}
}
}
// Couldn't fit in any children.
#if DEBUG
foreach (var child in Children)
{
Debug.Assert(child.Bounds.Contains(ref item.Bounds) != ContainmentType.Contains);
}
#endif
_items.Add(item);
item.Container = this;
return(true);
}