public static Vector3 GetBBCenter(this IHitable hitable)
{
var bb = hitable.GetGenericBoundingBox();
return(new Vector3(
(bb.Min.X + bb.Max.X) / 2,
(bb.Min.Y + bb.Max.Y) / 2,
(bb.Min.Z + bb.Max.Z) / 2
));
}
public BVHNode(params IHitable[] children)
{
if (children.Length == 0)
{
return;
}
AxisSelector.Axis sortingAxis = AxisSelector.GetMaxVarianceAxis(children);
IEnumerable <IHitable> sortedChildren = children.OrderBy(child =>
{
var bbCenter = child.GetBBCenter();
switch (sortingAxis)
{
case AxisSelector.Axis.X:
return(bbCenter.X);
case AxisSelector.Axis.Y:
return(bbCenter.Y);
case AxisSelector.Axis.Z:
return(bbCenter.Z);
default:
return(0);
}
});
switch (children.Length)
{
case 1:
Left = Right = children[0];
break;
case 2:
Left = children[0];
Right = children[1];
break;
default:
int firstHalfSize = children.Length / 2;
Left = new BVHNode(sortedChildren.Take(firstHalfSize).ToArray());
Right = new BVHNode(sortedChildren.Skip(firstHalfSize).ToArray());
break;
}
_boundingBox = new BoundingBox(Left.GetGenericBoundingBox(), Right.GetGenericBoundingBox());
}
