And while Mustang’s demo looks really cool, I can’t see how adding city lights and all the complexities will help answer the original question that was asked.
Mustang did answer the original question though, in 4 easy steps. He didn't provide a code snippet admittedly, but this should be straightforward stuff for anyone with a modicum of B3D experience.
Anyway, I hope Mustang is not put off by the criticism and does eventually release his demo.