/// <summary>
/// Adds the neighboring quad nodes.
/// </summary>
private void AddNeighbors()
{
switch (Type)
{
case NodeType.TopLeft:
#region The direct neighbors that DO NOT belong within the current node's parent:
// In case this is not the topmost quad node of the whole tree
if (Parent.NeighborTop != null)
{
// The parent's top neighbor's next-level bottom-left quad node.
// This is effectively the adjacent quad node of the same size as this one.
NeighborTop = Parent.NeighborTop.ChildBottomLeft;
}
// In case this is not the leftmost quad node of the whole tree
if (Parent.NeighborLeft != null)
{
// The parent's left neighbor's next-level top-right quad node.
// This is effectively the adjacent quad node of the same size as this one.
NeighborLeft = Parent.NeighborLeft.ChildTopRight;
}
#endregion
#region The direct neighbors within the same parent:
NeighborRight = Parent.ChildTopRight;
NeighborBottom = Parent.ChildBottomLeft;
#endregion
break;
case NodeType.TopRight:
#region The direct neighbors that DO NOT belong within the current node's parent:
if (Parent.NeighborTop != null)
{
NeighborTop = Parent.NeighborTop.ChildBottomRight;
}
if (Parent.NeighborRight != null)
{
NeighborRight = Parent.NeighborRight.ChildTopLeft;
}
#endregion
#region The direct neighbors within the same parent:
NeighborLeft = Parent.ChildTopLeft;
NeighborBottom = Parent.ChildBottomRight;
#endregion
break;
case NodeType.BottomLeft:
#region The direct neighbors that DO NOT belong within the current node's parent:
if (Parent.NeighborBottom != null)
{
NeighborBottom = Parent.NeighborBottom.ChildTopLeft;
}
if (Parent.NeighborLeft != null)
{
NeighborLeft = Parent.NeighborLeft.ChildBottomRight;
}
#endregion
#region The direct neighbors within the same parent:
NeighborRight = Parent.ChildBottomRight;
NeighborTop = Parent.ChildTopLeft;
#endregion
break;
case NodeType.BottomRight:
#region The direct neighbors that DO NOT belong within the current node's parent:
if (Parent.NeighborBottom != null)
{
NeighborBottom = Parent.NeighborBottom.ChildTopRight;
}
if (Parent.NeighborRight != null)
{
NeighborRight = Parent.NeighborRight.ChildBottomLeft;
}
#endregion
#region The direct neighbors within the same parent:
NeighborLeft = Parent.ChildBottomLeft;
NeighborTop = Parent.ChildTopRight;
#endregion
break;
}
if (hasChildren)
{
// recursively add neighbors for all children.
ChildTopLeft.AddNeighbors();
ChildTopRight.AddNeighbors();
ChildBottomLeft.AddNeighbors();
ChildBottomRight.AddNeighbors();
}
}
