A proper explanation of how graphics cards emulate real lighting conditions

This is a pretty cool video from NVIDIA about their new Maxwell architecture graphics cards (available in the NVIDIA GeForce GTX 980 and GTX 970 graphics cards). It's a thorough explanation of why realistic lighting is often so hard to recreate and even harder to render without proper GPU resources (we're talking about real-time rendering here).

It's a very simple animation but one that I think is pretty clear in why more and more, video games are harder to distinguish from real video.