Lens Matched Shading is another VRWorks feature that is a further refinement of the multi-projection architecture used in Maxwell, and takes into account lens correction that is necessary for users wearing VR headsets. In practice, this Pascal-exclusive feature reduces the number of pixels that need to be rendered to each eye, thus giving users a performance boost without downgrading peripheral fidelity (something that does take place with Multi-Res Shading).
Image on the left shows rending of more pixels than necessary before outputting final result to a headset.
“In technical terms, the final image shown in the headset is 1.1 Megapixels per eye, the first-pass image without Lens Matched Shading is 2.1 Megapixels per eye, and with Lens Matched Shading is just 1.4 Megapixels per eye,” writes NVIDIA. “That's a 50% increase in throughput available for pixel shading.”
Lens Matched Shading divides original image into quadrants beforehand to lower rendering requirements.
Given the stiff system requirements that are often necessary for a compelling VR experience, any “tricks” that can be deployed to improve performance is definitely welcome. In fact, NVIDIA says that the reduction in resources required have allowed developers to either make their software look even better, or step down the graphics requirements a bit to allow less powerful hardware to be used in VR titles.
To give you an idea of what kind of effect that Lens Matched Shading has on VR performance, Everest VR developer Solfar says that it has seen a 15 percent uplift in performance compared to Multi-Res Shading. That’s an impressive figure for sure, and we’re eager to see what kind of performance other developers will be able to extract with Lens Matched Shading.