/// <summary>
/// Splits node's primitives into 8 new children nodes.
/// </summary>
private void split()
{
if (boundingBox == null)
throw new Exception("Cannot split null bounding box");
try
{
this.childs = new OctreeNode[8];
for (int i = 0; i < 8; i++)
{
childs[i] = new OctreeNode();
childs[i].boundingBox = new BoundingBox(new Vector(), new Vector());
}
double dx2 = (boundingBox.RightBottomBack.X - boundingBox.LeftTopFront.X) / 2;
double dy2 = (boundingBox.RightBottomBack.Y - boundingBox.LeftTopFront.Y) / 2;
double dz2 = (boundingBox.RightBottomBack.Z - boundingBox.LeftTopFront.Z) / 2;
childs[0].boundingBox.LeftTopFront = boundingBox.LeftTopFront;
childs[1].boundingBox.LeftTopFront = boundingBox.LeftTopFront + new Vector(dx2, 0, 0);
childs[2].boundingBox.LeftTopFront = boundingBox.LeftTopFront + new Vector(0, dy2, 0);
childs[3].boundingBox.LeftTopFront = boundingBox.LeftTopFront + new Vector(dx2, dy2, 0);
childs[4].boundingBox.LeftTopFront = boundingBox.LeftTopFront + new Vector(0, 0, dz2);
childs[5].boundingBox.LeftTopFront = boundingBox.LeftTopFront + new Vector(dx2, 0, dz2);
childs[6].boundingBox.LeftTopFront = boundingBox.LeftTopFront + new Vector(0, dy2, dz2);
childs[7].boundingBox.LeftTopFront = boundingBox.LeftTopFront + new Vector(dx2, dy2, dz2);
Vector sizeVector = new Vector(dx2, dy2, dz2);
// all childs same size
for (int i = 0; i < 8; i++)
{
childs[i].boundingBox.RightBottomBack =
childs[i].boundingBox.LeftTopFront + sizeVector;
}
// distribute primitives into children
foreach (Primitive primitive in primitives)
{
// primitive may fall into multiple children at the same time
// ideally it will fall in only 1 child
for (int i = 0; i < 8; i++)
{
if (primitive.BoundingBox.Intersects(childs[i].boundingBox))
{
childs[i].Add(primitive);
}
}
}
primitives = null;
}
catch
{
// in case of exception clean up any inconsistencies
this.childs = null;
this.boundingBox = BoundingBox.Zero;
throw;
}
}
// checker. can be more than items inserted if some fall into multiple nodes
private int totalPrimitivesIn(OctreeNode node)
{
int sum = node.PrimitiveCount;
if (node.childs != null)
{
foreach (OctreeNode child in node.childs)
{
sum += totalPrimitivesIn(child);
}
}
return sum;
}
// returns all leaf nodes hit by the ray
private void traverse(OctreeNode node, Ray ray, LinkedList<OctreeNode> list)
{
if (node.primitives != null)
{
list.AddLast(node);
}
if (node.childs != null)
{
for (int i = 0; i < 8; i++)
{
if (node.childs[i].boundingBox.GetIntersection(ray) != Constants.Infinity)
{
traverse(node.childs[i], ray, list);
}
}
}
}
private void init()
{
compiled = false;
root = new OctreeNode();
bigObjects = new PrimitiveList();
}