public IEnumerable<int> GetQuadsInFrustum(Frustum frustum, bool treestart = false)
{
if (treestart || frustum.Check(BoundingBox))
{
if (SubContainer == null)
return new List<int> { ContainedQuad };
return SubContainer.SelectMany(container => container.GetQuadsInFrustum(frustum)).Where(quadId => quadId != -1);
}
return new List<int> { -1 };
}
