/// <summary>
/// Constructor.
/// </summary>
public SphereTree(int numChildrenPerNode)
{
// Store the number of children per node and clamp
_numChildrenPerNode = numChildrenPerNode;
if (_numChildrenPerNode < 2)
{
_numChildrenPerNode = 2;
}
// Create the root node
_root = new SphereTreeNode <T>(default(T), new Sphere(Vector3.zero, 1.0f));
_root.SetFlagsBits(BVHNodeFlags.Root);
}
/// <summary>
/// Integrates 'node' inside the tree. This is a recursive method which will
/// search for the best place where to place this node inside the tree.
/// </summary>
/// <param name="parent">
/// Keeps track of the current parent node we are processing., Allow us to keep
/// going down the tree hierarchy.
/// </param>
private void IntegrateNodeRecurse(SphereTreeNode <T> node, SphereTreeNode <T> parent)
{
// Are we dealing with a terminal node?
if (!parent.IsFlagBitSet(BVHNodeFlags.Terminal))
{
// This is not a terminal node. First thing to do is check if this node has
// room for one more child. If it does, we add the node here. Otherwise, we
// keep searching.
if (parent.NumChildren < _numChildrenPerNode)
{
node.SetFlagsBits(BVHNodeFlags.Terminal);
node.SetParent(parent);
parent.EncapsulateChildrenBottomUp();
}
else
{
// Find the child closest to 'node' and recurse down that path
SphereTreeNode <T> closestChild = parent.ClosestChild(node);
if (closestChild != null)
{
IntegrateNodeRecurse(node, closestChild);
}
}
}
else
{
// We have reached a terminal node. We have no choice but to create a new non-terminal
// node to take the place of the terminal one and then attach the integration node and
// the old terminal node as children of this new node.
SphereTreeNode <T> newParentNode = new SphereTreeNode <T>(default(T), parent.Sphere);
newParentNode.SetParent(parent.Parent);
parent.SetParent(newParentNode);
node.SetParent(newParentNode);
node.SetFlagsBits(BVHNodeFlags.Terminal);
newParentNode.EncapsulateChildrenBottomUp();
}
}
