This enumerated type is used in determining to what extent an object, the occludee,
is visible during horizon culling. An occluder may fully block an occludee, in which case
it has no visibility, may partially block an occludee from view, or may not block it at all,
leading to full visibility.
Members
Represents that an object is visible in its entirety.
Represents that no part of an object is visible.
Represents that part, but not all, of an object is visible