private void balanceSegment(Photon[] pbal, Photon[] porg, int index, int start, int end)
{
// compute new median
int median = 1;
while ((4 * median) <= (end - start + 1))
{
median += median;
}
if ((3 * median) <= (end - start + 1))
{
median += median;
median += start - 1;
}
else
{
median = end - median + 1;
}
// find axis to split along
short axis = 2;
if ((bboxMax.x() - bboxMin.x()) > (bboxMax.y() - bboxMin.y()) && (bboxMax.x() - bboxMin.x()) > (bboxMax.z() - bboxMin.z()))
{
axis = 0;
}
else if ((bboxMax.y() - bboxMin.y()) > (bboxMax.z() - bboxMin.z()))
{
axis = 1;
}
// partition photon block around the median
medianSplit(porg, start, end, median, axis);
pbal[index] = porg[median];
pbal[index].plane = axis;
// recursively balance the left and right block
if (median > start)
{
// balance left segment
if (start < (median - 1))
{
double temp = bboxMax.get(axis);
bboxMax.set(axis, pbal[index].position.get(axis));
balanceSegment(pbal, porg, (2 * index), start, (median - 1));
bboxMax.set(axis, temp);
}
else
{
pbal[2 * index] = porg[start];
}
}
if (median < end)
{
// balance right segment
if ((median + 1) < end)
{
double temp = bboxMin.get(axis);
bboxMin.set(axis, pbal[index].position.get(axis));
balanceSegment(pbal, porg, (2 * index) + 1, (median + 1), end);
bboxMin.set(axis, temp);
}
else
{
pbal[(2 * index) + 1] = porg[end];
}
}
}