Doom and Quake co-creator John Carmack is a legend in the computer industry. In a lengthy Facebook post, the Oculus CTO writes about his memories and relationship with another famous figure: Apple co-founder Steve Jobs.

Carmack reveals his teenage admiration for both Jobs and fellow Apple co-founder Steve Wozniak. He especially liked Jobs’ NeXT workstations and wanted to include the slogan “Developed on NeXT” on Doom. The request was denied, yet some time after Doom launched and had become a cultural phenomenon, Jobs said he would be happy for it to sport the NeXT brand. But as Carmack notes, “that ship had sailed.”

That situation reflected Jobs’ view on gaming. “Several things over the years made me conclude that, at his core, Steve didn’t think very highly of games, and always wished they weren’t as important to his platforms as they turned out to be,” Carmack writes. “I never took it personally.”

Carmack’s mission to get Apple to adopt OpenGL as its 3D graphics API led to a lot of arguments with Jobs. “Part of his method, at least with me, was to deride contemporary options and dare me to tell him differently. They might be pragmatic, but couldn’t actually be good. “I have Pixar. We will make something [an API] that is actually good.””

“It was often frustrating, because he could talk, with complete confidence, about things he was just plain wrong about, like the price of memory for video cards and the amount of system bandwidth exploitable by the AltiVec extensions.”

Carmack says getting Apple to adopt OpenGL resulted in his biggest indirect impact on the industry, as it led to phone makers adopting it when mobile devices started getting GPUs years later. This prevented a scenario where "half a dozen SoC vendors [roll] their own API back at the dawn of the mobile age."

Another incident saw Jobs try to get Carmack to reschedule his wedding so he could make a presentation at one of Apple’s keynotes. But their relationship hit its lowest point after a fight over letting apps run natively on the iPhone. Carmack believed that Apple could offer access to app developers that allowed them to create software that ran natively, all while keeping the iPhone secure. Jobs didn’t feel the same way. “He came back with a snide “You’re a smart guy John, why don’t you write a new OS?” At the time, my thought was, “F*ck you, Steve.” Thanks to other Apple executives convincing him, Jobs later changed his mind; a decision that led to the creation of the App store.

“The Steve Jobs “hero / shithead” rollercoaster was real, and after riding high for a long time, I was now on the down side. Someone told me that Steve explicitly instructed them to not give me access to the early iPhone SDK when it finally was ready.”

Carmack said that as Jobs’ health declined, he started writing several emails that he hoped would express something positive and meaningful to the Apple boss, but they were never finished—something Carmack regrets.