How could you say Steve Jobs is not a gamer? Look at that Atari joystick he’s holding!

When John Carmack talks publicly these days, he’s usually focused on intricate technical matters, the blue-sky potential of virtual reality, or occasionally business-focused lawsuits. So when the Doom co-creator and Oculus CTO used a lengthy Facebook post to open up about his memories of Apple’s late CEO Steve Jobs, it provided an interesting and rare look into two enigmatic tech luminaries.

Carmack leads off by recalling his fondness for Jobs’ expensive NeXT workstations, mentioning a failed marketing deal to feature “Developed on NeXT” branding on the original Doom, well before it was a cultural phenomenon. That failed marketing deal put Jobs and Carmack in each others’ orbit, a proximity which Carmack says he used to convince Jobs to adopt OpenGL 3D graphics standards on Macintosh, rather than using Apple’s own proprietary API.

Despite the problems with Apple’s OpenGL support (many of which the newer Vulkan standard seeks to fix), Carmack says getting Apple to adopt the open graphics standard ended up being key to getting mobile phone companies to adopt it years later, preventing a situation where “half a dozen SoC vendors [roll] their own API back at the dawn of the mobile age.” He considers that knock-on effect “one of the biggest indirect impacts on the industry that I have had.”