public void Construct(Aggregate aggregate)
{
Material = ((IIntersectable)aggregate).Material;
Aggregate objects = new IntersectableList();
foreach (IIntersectable intersectable in aggregate.GetObjects())
{
objects.Add(intersectable);
}
BoundingBox = ((IIntersectable)aggregate).BoundingBox;
//Calculate max treed depth = 8+1.3*log(n);
maxTreeDepth = (int)Math.Ceiling(8 + (1.3 * Math.Log(objects.Intersectables.Count)));
RootNode = new BspNode();
//Kick off the recursive tree construction
RootNode.BuildSubTree(objects, BoundingBox, maxTreeDepth, 0);
}
public void BuildSubTree(Aggregate intersectables, IBoundingBox boundingBox, int maxTreeDepth, int currentTreeDetph)
{
Intersectables = intersectables;
BoundingBox = boundingBox;
if (Intersectables.GetNumberOfComponents() <= 5 || currentTreeDetph == maxTreeDepth)
{
IsLeaf = true;
}
else
{
Aggregate leftIntersectables = new IntersectableList();
Aggregate rightIntersectables = new IntersectableList();
//Find the maximal Axis
Axis = 0;
float max = BoundingBox.Dimension.X;
if (BoundingBox.Dimension.Y > max)
{
Axis = 1;
}
if (BoundingBox.Dimension.Z > max)
{
Axis = 2;
}
//Axis = currentTreeDetph % 3;
PlanePos = BoundingBox.MaxVector[Axis] - (BoundingBox.MaxVector[Axis] - BoundingBox.MinVector[Axis]) / 2;
Vector3 leftMin = Vector3.Zero;
Vector3 leftMax = Vector3.Zero;
Vector3 rightMin = Vector3.Zero;
Vector3 rightMax = Vector3.Zero;
switch (Axis)
{
case 0:
leftMin = new Vector3(PlanePos, BoundingBox.MinVector.Y, BoundingBox.MinVector.Z);
leftMax = new Vector3(BoundingBox.MaxVector);
rightMin = new Vector3(BoundingBox.MinVector);
rightMax = new Vector3(PlanePos, BoundingBox.MaxVector.Y, BoundingBox.MaxVector.Z);
break;
case 1:
leftMin = new Vector3(BoundingBox.MinVector.X, PlanePos, BoundingBox.MinVector.Z);
leftMax = new Vector3(BoundingBox.MaxVector);
rightMin = new Vector3(BoundingBox.MinVector);
rightMax = new Vector3(BoundingBox.MaxVector.X, PlanePos, BoundingBox.MaxVector.Z);
break;
case 2:
leftMin = new Vector3(BoundingBox.MinVector.X, BoundingBox.MinVector.Y, PlanePos);
leftMax = new Vector3(BoundingBox.MaxVector);
rightMin = new Vector3(BoundingBox.MinVector);
rightMax = new Vector3(BoundingBox.MaxVector.X, BoundingBox.MaxVector.Y, PlanePos);
break;
}
IBoundingBox leftBb = new AxisAlignedBoundingBox(leftMin, leftMax);
IBoundingBox rightBb = new AxisAlignedBoundingBox(rightMin, rightMax);
LeftNode = new BspNode();
RightNode = new BspNode();
foreach (IIntersectable intersectable in Intersectables.GetObjects())
{
if (intersectable.BoundingBox.Intersect(leftBb))
{
leftIntersectables.Add(intersectable);
}
if (intersectable.BoundingBox.Intersect(rightBb))
{
rightIntersectables.Add(intersectable);
}
}
LeftNode.BuildSubTree(leftIntersectables, leftBb, maxTreeDepth, currentTreeDetph + 1);
RightNode.BuildSubTree(rightIntersectables, rightBb, maxTreeDepth, currentTreeDetph + 1);
Intersectables = null; //Clear up the intersectables in non leaf nodes to save space
}
}