proc aabb(self: VisibilityNotifier): AABB {.
gcsafe, locks: 0, raises: [], tags: []
.}

proc aabb=(self: VisibilityNotifier; val: AABB) {.
gcsafe, locks: 0, raises: [], tags: []
.}

proc isOnScreen(self: VisibilityNotifier): bool {.
gcsafe, locks: 0, raises: [], tags: []
.}