While Nvidia CEO Jen-Hsun Huang was busy brainstorming a surprise way to introduce the latest Titan X GPU, his research team was hard at work reducing the processing demands that future virtual reality games will impose on it.
The researchers concentrated on "foveated rendering," a graphics technique that has been around for more than a decade, but holds new promise for VR apps. By reducing the detail of images at the edges of a user's field of view, they can create smoother VR experiences with less processing power.
At its most basic, foveated rendering is a simple two-step process, despite its lofty name. The sides of an image are first blurred to reduce the amount of rendering power required to display them. Then, their contrast is increased to help them blend in with the rest of the fully rendered image.
If it's done right, your eyes will hardly tell the difference. If it's done wrong, you'll experience a bad case of tunnel vision. The goal, explains Nvidia graphics research director Aaron Lefohn, is to concentrate the foveation on "pixels they can't see because they're in people's peripheral vision."
"If you get this right, you can do all kinds of things," he said. Getting it right in VR, though, requires extremely accurate eye tracking, something that itself requires lots of processing power and very low latency. Lefohn's team enlisted SensoMotoric Instruments to develop the eye-tracking algorithms and prototypes of infrared sensors that surround the edges of a the lens in VR glasses.
Like VR in general, it's still early days for Nvidia's foveated rendering. It works in the lab, but device manufacturers like Oculus and HTC will have to incorporate it into their hardware, and developers will have to support it in their games and apps.
Still, Lefohn is drawn to what he sees as foveated rendering's universality, in that it harnesses the immense power of virtual reality itself.
"It's applicable to any VR experience that's eye-tracked," he said. That could include anything from quicker display calibration to enhancing the movement of a player's avatar.