During the presentation of its GeForce RTX 2080 graphics cards last week, Nvidia spent most of its time on ray tracing. This is the high-end light modeling tech that could bring a new level of realism to games. But these new cards can do more than just ray tracing. One of the other potential standout features is variable-rate shading, which is a powerful feature that is an important prerequisite to another technology called foveated rendering.
Dynamic foveated rendering is a process that only fully renders the part of the screen you are looking at. Everything outside of that circle of focus is only as detailed as your brain needs to convince you it is real. This is beneficial because it saves the graphical horsepower of a computer only for the part of the image that matters, and all of the power that foveated rendering saves can get put back into making the focal point look even better.
Foveated rendering is something that could start showing up in more places — especially in virtual reality. Saving processing power is crucial to keeping high framerates in VR, and that’s a big problem for standalone headsets that could replace the current tethered solutions.
Nvidia’s new GPUs, the RTX 2070, 2080, and 2080 Ti, all come with support for the variable-rate shading that should enable foveated rendering. I won’t pretend to fully understand how variable-rate shading works. It’s something Microsoft only just patented in February. But put in simple terms, it enables a graphical program to switch the quality of rendering of certain parts of a 3D scene on the fly. This quick switching in quality should enable the rendering side foveation to keep up with the movement of your eyes.
As for keeping track of where you’re looking, we already have that technology in the Tobii Eye Tracker. That imaging device can look at your eyes and understand exactly where on a screen you’re looking.
I reached out to Tobii to ask it about variable-rate shading, and it sees this as a major chance for the tech to take off.
“Nvidia’s new variable-rate shading creates many opportunities for rendering optimization, including benefits for eye-tracking based foveation driven by Tobii eye tracking hardware and SDKs,” a Tobii spokesperson said. “As more organizations across the hardware and software ecosystem develop and evolve native support for foveated rendering related features, we should expect increasingly better results.”
Of course, Tobii recognizes that no one piece of the puzzle is going to lead to an adoption of foveated rendering overnight. The technology is going to need time.
“The reality is that while key components such as the GPU and eye tracking hardware are important parts of making foveated rendering a reality,” Tobii’s spokesperson said. “Fully realizing the benefits requires that every part of the stack — like the CPU, GPU, game engine, and eye tracking hardware — is designed and optimized to support foveated rendering. The good news is that there is rapid progress happening right now in these areas, bringing the promise of this technology closer than ever.”
The bottom line here, though, is that the inclusion of variable-rate shading in the RTX chips should make it even easier for the other parts of the rendering chain. Tobii expects game engines to quickly implement support for dynamic foveation based on what the Nvidia cards are capable of, and then that should enable developers to experiment with the tech.
And if you’re skeptical of the tech, don’t be.
It works so well that it’s scary.