Developer Infinity Ward's game engine runs one of the most popular franchises in the world at 60 frames per second every tear, and it doesn't even have a name.
Later this year, the developer will release Call of Duty: Ghosts, a pivotal installment in the first-person shooter phenomenon. It will introduce new characters and a new sub-brand to the Call of Duty franchise, and it's being built in a new engine designed to take advantage of next-gen consoles.
"We're not engine guys, in the sense that we don't sell our engine," Mark Rubin, executive producer at Infinity Ward, told Polygon at E3 2013. "We're not trying to market our engine. We don't even, you know, name it. It doesn't even have a name. It's just called IW6 because it's the sixth engine we made, so we just call it IW6."
Though Infinity Ward is referring to the engine as new, it is informed by what the developer learned creating its first five iterations. Thanks to the new hardware on next-gen platforms, however, it's allowed Infinity Ward to implement features that weren't possible on current-gen systems.
"You don't go, 'Okay, all that stuff we did is gone. Let's bring out a blank piece of paper. Wait! We've got pencils! Alright, let's start writing.' No, it doesn't work that way," he said with a laugh.
"The components of that engine, a lot of them actually did start from blank paper. You don't just take a lighting engine and go, 'Okay. You're now a new lighting engine. There's no switch. So you do rewrite from scratch a lot of the components. What we keep, though, is that structure. The structure and the way we do things. The pipelines. You don't want to drastically change the way your pipelines work, so you keep that kind of philosophy and that kind of skeleton, and then you rewrite the components that go on that skeleton."
We got a look at IW6 in action during E3. Two of the three campaign levels we were shown — "No Man's Land," staring Riley the dog and the underwater excursion called "Into the Deep" — will be familiar to those who watched the game's pre-E3 reveal and show the lighting and texture upgrades that bring a greater sense of realism to the franchise. A third level, "Federation Day," which took place in Caracas, Venezuela, made a brief appearance during the reveal, particularly in a shot of a soldier cutting through glass on the side of a high-rise.
It began on a rooftop with fireworks, which highlighted the IW6 engine's lighting prowess. As the elite soldiers shot mounted their zip lines and took to the skies above the streets below, we could see the series' trademark fluidity of motion, but this time rendered in much greater detail, thanks to the high-res textures — another benefit of the retooled engine.
"We can create assets that are super high quality, cinema quality assets, and those assets we use as source to create the best-looking assets for each platform, rather than what we used to do: make one asset that has to look good on all the platforms," he said.
To Rubin, IW6 is really about three "big pillars" that he's most excited about. The first is the lighting and the textures and the game's ability to scale based on what's seen and needed at the time. The second is a layer on top of that: the game's new audio engine, which models sound based on the entire environment. If you're in a steel room, the reverb reflects that. The same applies if you're in an open field or a jungle. Moreover, if there's a jungle on your left and a wooden building on your right, the ADSR audio engine will account for both in real-time.
The third feature is a retooling of the first-person animation system, which he said will bolster the game's fluidity. Now, when a character is running toward a wall, you can press a button within a certain window and your charter will vault over it seamlessly. In Call of Duty: Ghosts, there's no more stopping and standing and pressing a button to advance.
All of these changes, he said, are in service of immersion.
"For us, I think we would fail if you go into the game and you're going, 'That tech looks awesome.' Because we don't want you to focus on the tech. We want you to focus on the experience, that immersion. We want you to go into a level and be so into it and never pulled away from it. And that's the key.
"If you come up and are like, 'Oh, wow! They have the volumetric lighting looks — that's a really cool way they're doing it. Look at the way the shadows...' No! Don't look at that. Play the game and enjoy the experience.
"You want people to just forget they're playing a game."