[joakleaf]

He was developing large parts of e.g. Doom: He didn't write the BSP traversal and texture mapper (the graphics engine), but he did write monster AI, level behavior, and level editor.

I think, I heard him state in an interview that he also did a lot of development on Quake in addition to the levels. Obviously the graphics engine was Abrash and Carmack's

[rckclmbr]

I think Carmacks programming principle would be "be a genius"

[jackmott]

No, if you learn more about him, its really more work ethic. I think he is smarter than an average person, but not smarter than the average programmer by a whole lot. Just robotic like work ethic.

[patrickyeon]

There's a bit at the end of Chuck Yeager's autobiography, where he takes to task the idea of test pilots being men who have "the right stuff" (specifically addressing the book by that title).

"And in the end, the one big reason why I was better than average as a pilot was because I flew more than anybody else. If there is such a thing as 'the right stuff' in piloting, then it is experience."

[Koshkin]

Then mine would be "don't be an idiot." :)

[erikbye]

Carmack has programmed professionally at least since 1990, he was 19 then, 20 when he founded id Software. Genius or not, he obviously has a lot of programming experience, and familiarity with a subject counts for a lot. He has worked really hard, written millions of LoC. Obviously his "genius" lies not in learning a programming language and syntax, anyone can do that. But he evidently has a knack for developing new techniques (e.g. in graphics). He has a good understanding of especially light physics and hence physical based rendering. Considering his ventures with Armadillo Aerospace it's probably safe to say he's got a good understanding of physics in general. How many game developers went from games to aerospace?

http://www.geek.com/geek-cetera/elon-musk-and-john-carmack-t...

https://techcrunch.com/2015/01/16/elon-musk-tries-to-woo-joh...

Elon Musk practically offered Carmack a job at SpaceX, tweeting "Well, if you love rockets, come work on them with me at SpaceX!"

Carmack is a very enthusiastic person, who is hard working, and genuinely passionate about everything he pursues. I have "followed" him for a good while. It's not difficult to tell he's a lot smarter than your average Joe, but he also seems quite a bit sharper than your average smart programmer. I recommend watching all his talks and interviews.

Some amusing and revealing stuff on his childhood: http://www.giantbomb.com/john-carmack/3040-4576/

"In the gaming industry, there are a lot of people that are specifically in it because they love games and they want to create things. My love for programming is a more abstract thing. I'm taking a great deal of enjoyment writing device drivers for Linux. I could also be having a good time writing a database manager or something because there are always interesting problems. There are some things that are inherently more rewarding than others. Graphics and games are probably the most generally rewarding area of programming."

On software engineering: https://www.youtube.com/watch?v=wt-iVFxgFWk

Another smart and nice guy in the business is Tim Sweeney. About the same age as Carmack, and also founded Epic the same year id Software was founded, at 21. Sweeney got his first taste of programming at 11.

"It was astonishing seeing the IBM PC. It was such a crisp machine. I'd seen a Commodore PET computer before, and it was a crappy device that never really did what you wanted, I couldn't figure it out and nobody was there to show me how to use it. I sat down at this IBM and every key you pressed made this bright, quick sound. [It had] this nice clear screen, this very powerful basic programming language. It just took me a couple of days to figure out how to use that. It was totally love at first sight. From that point on, I tried to dedicate all of the time I had free to learning to do more with computers."

He seems to share a similar passion to that of Carmack's.