Recently Oculus announced the release of Asynchronous SpaceWarp 2.0 for the Rift. It’s an upgrade to its ASW technology for smoothing out visuals inside headset to reduce latency and compensate for fluctuations in performance. Both SpaceWarp (to smooth frame motion) and TimeWarp (to keep latency low) are combined by ASW for apps that can’t keep a stable 90 FPS to complement 90Hz display of Rift. Furthermore, it maintains satisfactory visual performance even with lower-end hardware when running virtual reality apps even at 45 FPS.
TimeWarp works by sampling the headset position at the last second, once rendering of latest frame is done, thus warping the frame to match user’s head motion just before it is sent to the display in headset. Consequently, a significant reduction is noticed in the perceived latency.
In its previous version, ASW 1.0, all positional movement were left untouched and TimeWarp was only functional for headset rotation. However, ASW reduces positional latency as well as TimeWarp can also be applied on position. This is done when depth information is leveraged from a virtual reality app, accounting for positional movement by allowing the frame to be accurately warped at the last moment. This upgrade is also predicted to have a better control of performance fluctuations.
While the previous version performed well provided that the app could keep up a 45 FPS rate, it failed to maintain smooth motion when a further drop in framerate was noticed. However, ASW 2.0 is capable of maintaining a satisfactory view in virtual reality even at less than 45 FPS. This is because for lower frame rates, depth based reprojection of positional TimeWarp works more accurately.
When depth information is incorporated into calculations, it allows the new version to predict how different parts of the same scene should move in interpolated frame, particularly in difficult cases such as high contrast patterns.
“Most Rift apps on the Oculus Store built on Unreal Engine 4 and Unity already provide the depth information required to make ASW 2.0 work.”
~ Oculus
Despite having a better functionality and upgraded features, not all apps will be compatible with ASW 2.0 but many will. The apps that don’t work with the new version will need to be updated to benefit from the functionalities provided by it. All in all, apps that are developed such that they work in synch with Oculus Dash interface are already built correctly, making them automatically compatible with ASW 2.0.