John D. Carmack II (born August 20, 1970) is an American computer programmer and video game developer. He co-founded the video game company id Software and was the lead programmer of its 1990s games Commander Keen, Wolfenstein 3D, Doom, Quake, and their sequels. Carmack made innovations in 3D computer graphics, such as his Carmack's Reverse algorithm for shadow volumes. In 2013, he resigned from id to work full-time at Oculus VR, where he served as CTO and later Consulting CTO in 2019.