public BVHNode(Hitable[] p, int n, float time0, float time1)
{
int Compare(Hitable a, Hitable b, int i)
{
AABB l = new AABB(), r = new AABB();
if (!a.BoundingBox(0, 0, ref l) || !b.BoundingBox(0, 0, ref r))
{
throw new Exception("NULL");
}
return(l.min[i] - r.min[i] < 0 ? -1 : 1);
}
Hitable[] Split_array(Hitable[] Source, int StartIndex, int EndIndex)
{
var result = new Hitable[EndIndex - StartIndex + 1];
for (var i = 0; i <= EndIndex - StartIndex; i++)
{
result[i] = Source[i + StartIndex];
}
return(result);
}
var pl = p.ToList();
var method = (int)(3 * MyLabrary.Random.Get());
pl.Sort((a, b) => Compare(a, b, method));
p = pl.ToArray();
switch (n)
{
case 1:
left = right = p[0];
break;
case 2:
left = p[0];
right = p[1];
break;
default:
left = new BVHNode(Split_array(p, 0, n / 2 - 1), n / 2, time0, time1);
right = new BVHNode(Split_array(p, n / 2, n - 1), n - n / 2, time0, time1);
break;
}
AABB box_left = new AABB(), box_right = new AABB();
if (!left.BoundingBox(time0, time1, ref box_left) || !right.BoundingBox(time0, time1, ref box_right))
{
throw new Exception("no bounding box in bvh_node constructor");
}
box = GetBox(box_left, box_right);
}
public FilpNormals(Hitable p) => hitable = p;
