Facebook may face legal troubles over its purchase of virtual reality (VR) firm Oculus, as US games firm ZeniMax claims that it owns key parts of the technology.
ZeniMax is the former employer of John Carmack, the gaming legend who developed Doom and was hired to much acclaim by Oculus as chief technology officer in August 2013. In letters sent by ZeniMax to Oculus and Facebook, the firm claims that Carmack shared its intellectual property (IP) with Oculus, both before and after he joined the company.
Carmack, though, seems unhappy about the manoeuvring, and has tweeted to distance himself from it .
The Wall Street Journal's Liz Hoffman and Reed Albergotti report ZeniMax's allegation that it was its IP which propelled Oculus into the big leagues, and put it in the position to be acquired by Facebook.
The dispute dates to 2012, when Carmack was working for ZeniMax subsidiary ID Software. Carmack contacted Oculus founder Palmer Luckey, and received a prototype headset from the firm, which he demonstrated in modified form at that year's E3 convention; in one video from August's Quakecon, Carmack talks about the extent to which his software helped get Oculus working.
"I was heading down almost the same route on there. I was cobbling some things together myself," Carmack said at Quakecon. "I ran into Palmer [Luckey] and he had basically built something probably better than something I would have done if I had put it together myself. So I'm like, OK, I can abandon work on all of these projects and this is the platform."
"Mostly as a software guy, I want something to write software for," he continued. "It's fun to tinker with the hardware, but I'd really just as soon have someone else do that. It's only in cases where I can't see someone else doing the right thing that I find the need to make something happen myself."
ZeniMax began talking with Oculus about compensation for this work in August 2012, the Journal reports.
But Carmack seems unhappy about the moves. Since the news broke, he has tweeted that "No work I have ever done has been patented. Zenimax owns the code that I wrote, but they don't own VR" and later added "Oculus uses zero lines of code that I wrote while under contract to Zenimax."
In September 2012, Oculus closed its Kickstarter campaign having raised $2.5m. Eighteen months later, the firm sold to Facebook for $2bn.
ZeniMax itself has little public profile, but the company's subsidiaries include Carmack's ID Software, which developed the Doom and Quake series, and Bethesda, developer and publisher of the Elder Scrolls and Fallout games. It is privately held, the largest of its sort in the US video games industry.
• Oculus: Facebook buys virtual reality gaming firm for $2bn
