Black Ops II is based on earlier code, but improvements have been made to the graphics.
A entirely new game engine isn't required in order for Treyarch to push Black Ops II's visuals further than previous Call of Duty games, studio head Mark Lamia has told One of Swords.
"People always ask me, 'Is this a new engine?' I liken it to people who live in an older house that has been remodelled. Just because you're remodelling the house and it will look new or it will have a new kitchen, you don't tear out the foundation, or break out some of the framing. You might even go as hardcore as replacing the plumbing, and we will do that sort of thing, as an analogy. It's a gross simplification, but it's one way to say that. There's a lot of good still in that foundation that you wouldn't get rid of, and we don't. We look to advance in the areas that support our game design.
"Engines, each time they get touched, they change. The creators alter them; they don't modify what they don't need to, and then they alter what they need to. You can't make a competitive product if you're not upgrading that engine along the way."
Lamia added: "I think the whole thing about a new engine...sometimes that's a great buzzword. Well, I have a new graphics engine - is that a new engine? Where does it start and stop? Elements of the code, you can trace back for a very very long time...but whole parts of the code are entirely new. Two areas we did focus on for this game were the graphics and the lighting - a pretty significant amount of work is going into that."
He concluded: "I think what people are asking for is for us to push. They want us to make a better-looking game; they want things. I don't think those are things people can't ask for. We asked ourselves that very same question - we wanted to advance the graphics. I think the questions are valid. The answer may not need to be an entirely new engine, but you might need to do an entire overhaul of your entire lighting system.
"The trick is, we're not willing to do that if we can't keep it running at 60 frames per second - but we did that this time. So this is the Black Ops II engine."
Black Ops II will be released November 13.