Valve has released a new patch for its virtual reality title, Half-Life: Alyx, adding support for foveated rendering in the PC version of the game. This update comes six years after the game's initial release and offers a way to potentially improve performance, especially for players using VR headsets equipped with eye-tracking technology.
The foveated rendering option can be found within the Advanced Performance settings menu. According to Valve's patch notes, enabling this feature can increase rendering performance. For DirectX, it is supported on Nvidia GTX 16XX series and newer, as well as RTX 20XX series and newer. AMD users can enable it by launching the game with the '-vulkan' command-line argument. The developers note that enabling eye-tracking on the headset provides the best results.
Foveated rendering functions by rendering the center of the image, where the user's gaze is focused, at a higher quality, while the peripheral areas are rendered at a lower resolution. This technique reduces the overall rendering load on the system. When combined with eye-tracking, the game can dynamically adjust the rendering quality to ensure the area of clearest vision is always rendered at its best.
While foveated rendering can technically be enabled on any VR headset, Valve highlights several headsets where it is particularly effective or supported, including the Steam Frame, Meta Quest Pro, Bigscreen Beyond 2e, Apple Vision Pro, PS VR2, Pimax Dream Air, Pimax Crystal series, and Varjo Aero, among others.
This implementation of foveated rendering is distinct from foveated streaming, a technology used for reducing bandwidth for wireless VR gaming, such as on the Steam Frame itself. The PC Gamer review of the Steam Frame noted that the foveated rendering implementation in that port was noticeable, with visible edges between high and low-quality rendering areas. Nevertheless, the update is expected to be beneficial for players experiencing performance issues on high-resolution VR headsets.