8 Questions with John Carmack

Amber Bouman

John Carmack needs no introduction - since 1991 he's been the main engine development guy for id Software . Shortly after his 40th birthday, we caught up with the tru engineer for a quick 8-question Q&A.

Do you have a target performance level or specific platform in mind when you begin planning your engines?
For this generation, we picked the 360 / PS3 as the target platform, knowing that the PC platform would be well past that performance level when we were done.  I am thinking about the next generation now, which is rather difficult because we don’t know much about what is being considered for future consoles.  I may just try to see what I can do with a state of the art PC platform in research mode.

What’s been the most challenging aspect of building the id Tech 5 engine?

The enormous virtual textures have been challenging for both the workflow and runtime code, but that was the core bet that we made for the project.

We’re curious to hear your take on hardware-accelerated tessellation. Any thoughts?
Tesselation has been expected to be “the next big thing” for the last three hardware generations.  It hasn’t been.  Extreme geometric smoothness is needed for movie rendering where it is common for a character’s face to occupy the entire screen for extended periods of times, but that isn’t common for games.  In most cases, the additional vertexes needed for the control mesh on traditional geometric patches could be better spent on additional interesting triangular detail.

With the very latest generation of hardware, we may finally be at a point where displacement mapped surfaces are a credible design target.  It has been possible to do it for a while, but it only makes good sense when the average triangle size gets down to only a couple pixels, which used to waste large fractions of the fill rate on GPUs.  Good anti-aliasing is also required to prevent all those tessellated and displaced edges from turning into a ton of noise on screen.

If it doesn’t turn out that some form of ray tracing can cut it for our next gen game engine, my fallback plan has always been to extend the current megatexture architecture and workflow to support unique displacement maps on the entire world.



What kind of system have you been using to work on the new engine?

I have been using an eight core intel system, but I am upgrading to a 12 core/24 thread system this week.  A 64 bit OS is now mandatory for our development tools.

Will we be able to benchmark using Rage / id Tech 5?
We haven’t added specific benchmark code yet, but I’m sure we will before shipping.  It will be a little more complicated because of the dynamic streaming nature of the texturing, so we will probably have to offer a “locked page file cache” option or possibly a “no texture updates” option to give repeatable results.

A lot of attention has focused on how id Tech 5 is more developer-friendly. Beyond this, what other features are you most excited about?
The combination of designed-for-60fps gameplay and the character that the world has with the unique art everywhere are the prime things that the technology has enabled.  Every aspect of the game is damn good, but my involvement in performance and graphics biases my views.



What’s your take on PC gaming these days? Last year, people were saying it’s dead, which was clearly an exaggeration. The category feels like it’s picking up now, however.
We expect to be successful in the PC market, but the consoles are still the dominant targets for an action game.

As you approach your 40th birthday, do you have any reflections on some of the gaming-related tech you’ve helped kick-start -- the first person-shooter genre; 3D acceleration; etc – or PC gaming in general? Are you still playing games?
I did go through a period where I had pretty much stopped playing games, but in recent years I have been playing regularly with my son, which has been a good thing for my engagement with my work.  I’m proud of what I have done, but I almost never reminisce about the past, because I am so excited about the present and future.

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