A 17-year-old and his older brother made $20 million from a game they built themselves in Nanterre, France. Their core discovery was about the human brain, and the entire game industry missed it for twenty years. Bodycam looks like leaked combat footage. Not "impressive graphics." Footage. Here's the trick. The brothers didn't hand-model their forests and buildings. They used photogrammetry libraries, where every log, wall, and patch of dirt is a 3D scan of a real log, wall, and patch of…