Just before the launch of the SteamVR-powered HTC Vive in 2016, Valve released a hardware testing tool to establish a minimum GPU power baseline for virtual reality. Now, with the impending release of the higher-resolution Vive Pro, Valve is updating SteamVR to ensure that higher-end headsets will work well at a variety of GPU power levels.
The auto-resolution scaling system, as described in a Steam Community announcement today, measures "how many 'VR megapixels per second' we believe your GPU is safely capable of for the majority of applications available." That number is then used to calculate the appropriate native resolution for the VR app being run, regardless of the display resolution of the attached VR headset.
That means systems with high-end GPUs will automatically see VR apps "up-res'ed" to "fully utilize" the power of the graphics card, Valve writes. The effect of that change will be most apparent on high-end headsets like the upcoming Vive Pro (which includes two 1400×1600 resolution displays) and certain Windows Mixed Reality headsets, but this kind of native "supersampling" can improve the clarity of VR apps even on years-old, "low-end" headsets like the Vive and Oculus Rift (which both have dual 1080×1200 displays).
If your gaming rig can't quite hit the maximum display resolution and frame rate of the Vive Pro (or future high-end headsets), SteamVR will automatically render your VR apps "at a slightly lower resolution" to maximize clarity while providing a consistent frame rate. That automatic resolution downscaling will never dip below the 1080×1200 per eye minimum set by the Vive and Rift, though, and can be overridden in Steam's Video settings if you want to push your hardware a bit more than the recommended level.
As described, it sounds like the new auto-scaling system sets a single VR resolution target for your GPU based on "the majority of applications available" rather than customizing based on the level of detail and scene complexity of the specific VR app being run. It also sounds like the system sets a single static resolution for the app rather than dynamically scaling based on real-time GPU utilization, a method Valve itself has shown can help maximize performance while maintaining consistent frame rates.
Details aside, Valve writes, the point of the update is to essentially "take the headset out of the equation for [VR] developers." Rather than having to tune VR performance for a wide array of different display resolutions and refresh rates, those developers can now "test their application against the GPUs they support without worrying about what future headsets will require." All SteamVR apps will work with the resolution scaling technology without the need for an update.
The auto-scaling system also means gamers won't absolutely need to upgrade their PC hardware when they upgrade their VR headset, Valve writes. With resolution auto-scaling, you can buy a Vive Pro even if your gaming rig is only powerful enough for the 2016 edition of the Vive, secure in the knowledge you'll be getting your machine's maximum VR graphics performance now and also if and when you upgrade to a new GPU.
"This is exactly what most PC games have done for decades for different resolution monitors and TVs," Valve writes. "We are now applying this same logic to the SteamVR runtime that will then set the resolution for all VR applications running through Steam on your system."