Just wondering if there is some kind of solution already in Unreal to do this: How Valve got passable VR running on a four-year-old graphics card | Ars Technica
Where by defining regions of the render, you can keep highRes in the middle, 3/4 on the borders and even expand it like 3 concentric circles where:
- The center is HighRes
- The second one is 3/4 Res
- The last one is half Res