public KDopBounds SplitTriangleList(int startIndex, int numTriangles, KDopTree kDopTree)
{
if (numTriangles > 4)
{
isLeaf = false;
int BestPlane = -1;
float BestMean = 0.0f;
float BestVariance = 0.0f;
for (int nPlane = 0; nPlane < KDopTree.NUM_PLANES; nPlane++)
{
float Mean = 0.0f;
float Variance = 0.0f;
for (int nTriangle = startIndex; nTriangle < startIndex + numTriangles; nTriangle++)
{
Mean += kDopTree.triangles[nTriangle].GetCentroid()[nPlane];
}
Mean /= (float)numTriangles;
for (int nTriangle = startIndex; nTriangle < startIndex + numTriangles; nTriangle++)
{
float Dot = kDopTree.triangles[nTriangle].GetCentroid()[nPlane];
Variance += (Dot - Mean) * (Dot - Mean);
}
Variance /= (float)numTriangles;
if (Variance >= BestVariance)
{
BestPlane = nPlane;
BestVariance = Variance;
BestMean = Mean;
}
}
int Left = startIndex - 1;
int Right = startIndex + numTriangles;
while (Left < Right)
{
float Dot;
do
{
Dot = kDopTree.triangles[++Left].GetCentroid()[BestPlane];
}while (Dot < BestMean && Left < Right);
do
{
Dot = kDopTree.triangles[--Right].GetCentroid()[BestPlane];
}while (Dot >= BestMean && Right > 0 && Left < Right);
if (Left < Right)
{
KDopTriangle Temp = kDopTree.triangles[Left];
kDopTree.triangles[Left] = kDopTree.triangles[Right];
kDopTree.triangles[Right] = Temp;
}
}
if (Left == startIndex + numTriangles || Right == startIndex)
{
Left = startIndex + (numTriangles / 2);
}
KDopNode leftNode = new KDopNode();
int leftNodeIndex = kDopTree.nodes.Count;
kDopTree.nodes.Add(leftNode);
data.leftNode = leftNodeIndex;
KDopNode rightNode = new KDopNode();
int rightNodeIndex = kDopTree.nodes.Count;
kDopTree.nodes.Add(rightNode);
data.rightNode = rightNodeIndex;
KDopBounds leftBoundingVolume = leftNode.SplitTriangleList(startIndex, Left - startIndex, kDopTree);
KDopBounds rightBoundingVolume = rightNode.SplitTriangleList(Left, startIndex + numTriangles - Left, kDopTree);
boundingVolumes.Encapsulate(leftBoundingVolume);
boundingVolumes.Encapsulate(rightBoundingVolume);
kDopTree.nodes[leftNodeIndex] = leftNode;
kDopTree.nodes[rightNodeIndex] = rightNode;
}
else
{
isLeaf = true;
data.startIndex = startIndex;
data.numTriangles = numTriangles;
for (int triIndex = data.startIndex; triIndex < data.startIndex + numTriangles; ++triIndex)
{
KDopTriangle tri = kDopTree.triangles[triIndex];
boundingVolumes.Encapsulate(tri.v0);
boundingVolumes.Encapsulate(tri.v1);
boundingVolumes.Encapsulate(tri.v2);
}
}
return(boundingVolumes);
}
