John Carmack is a game programmer, aerospace and virtual reality engineer. He co-founded id Software. Carmack was the lead programmer of COMMANDER KEEN, WOLFENSTEIN 3D, DOOM, QUAKE, RAGE and their sequels. Carmack is known for his innovations in 3D graphics, such as his Carmack's Reverse algorithm for shadow volumes, and is also a rocketry enthusiast and the founder and lead engineer of Armadillo Aerospace. In August 2013, Carmack left id to take the position of Chief Technology Officer at Oculus VR.