We’ve had a writer in a Dallas courtroom following the ZeniMax vs. Oculus court case this week and taking notes. Covering a court case as technical as this is new for us, as is the fast paced back and forth of questioning, so we are planning to dive more deeply into the specifics of the case as it progresses.

That said, our writer on the ground reports Oculus CTO John Carmack was on the stand much of the week as ZeniMax seemed to push for evidence in questioning that he violated his agreements with the company and shared information he shouldn’t have with Oculus.

The case, filed by ZeniMax after the 2014 acquisition of Oculus by Facebook for more than $2 billion, centers on Carmack’s agreements with ZeniMax as well as information and technology he allegedly shared with Oculus co-founder Palmer Luckey. In 2013 Carmack left ZeniMax-owned Id Software, the videogame company Carmack co-founded in 1991, to become the chief technology officer at Oculus, though he was involved as early as 2012 in helping popularize the Oculus Rift.

I wanted to remain a technical adviser for Id, but it just didn’t work out. Probably for the best, as the divided focus was challenging. — John Carmack (@ID_AA_Carmack) November 22, 2013

Carmack is “a singularly experienced and highly proficient” programmer, as an amended complaint by ZeniMax describes him, and he’s popularly known as one of the fathers of modern 3D gaming, as well as for giving multi-hour technical talks at conferences with no speaking notes or breaks. This week, he answered hours of questions.

Among the exchanges our ears in the room overheard, he explained in open court what source code is and that ‘BFG’ stands for ‘Big Fucking Gun.’ In some instances his back and forth during questioning became relatively heated, with ZeniMax attorney Anthony Sammi pressing for answers about how Carmack handled certain computer equipment. One line of questioning asked whether Carmack knew about a “secret meeting” in a hotel room with Oculus co-founders Nate Mitchell and Palmer Luckey, to which Carmack responded “No I didn’t, it was a secret.” A MacBook was brought up during questioning as well, with the lawyer asking why it was never wiped, with Carmack responding: “I am not a Mac user unless under duress.”

The defense for Oculus is expected to weigh heavily on showing the jury that the startup designed all the components of the first Rift development kit, and developed its own software development kit without software or hardware from ZeniMax. One exchange in particular between Carmack and Sammi underscored the different claims being made in the case about the technical contributions made to the Rift, with Carmack saying early on that “Palmer provided the system” while Sammi claimed “Palmer provided the simple lenses.”

Editor’s Note: Writer Garrett Glass is in a Dallas courtroom this week following what’s going on for UploadVR. Stay tuned for more updates as the case continues next week.