Asynchronous Spacework works by intervening every frame in order to time wrap the last submitted eye buffers and this works even if the application is taking long to render the next frame. The low frame rate of 45fps is compensated by adding artificial frames and achieving the 90fps required for VR experience. Asynchronous Spacewarp (ASW) is a frame-rate smoothing technique that halves the CPU/GPU time as we explained earlier. The ASW has enabled automatically and doesn’t require the developers to make any changes to accommodate the same. Also, ASW helps in minimizing the latency and improves the overall experience of the particular software and hardware combination. The best part is that ASW will scale the current content to suit devices with lower specs. This is how it all happens, ASW works in sync with ATW to cover all the visual motion in the virtual reality motion including the camera movement, Touch controller movement, and the player’s positional movement. In cases where the application is behind the frame rates the experience is expected to be at its best. Well, for a better understanding of ATW have a look at the scene below. It’s a simple scene wherein the gun is moving from right to left. The gun moves from Frame 0 to Frame 1 and then the application displays a generated frame based on the movement of the gun thus compensating for the lower framerate.
The ATW and the ASW are like brothers in arms and kind of complement each other, while TimeWarp is great for head rotation the Spacewarp is good for animated objects that are in close range. With both the technologies working in tandem, the effective latency is kept low and head tracking remains as smooth as it would have been on a high specced machine. That said, the very fact that the visuals are rendered at half the framerate can cause some undesirable effects like Rapid brightness changes, pattern repeats and fast movement of head locked units. Perhaps this is the very reason that Oculus still suggests that developers should maintain 90 fps rendering on the recommended spec systems. Furthermore, the ASW is not needed in the machines with higher configurations and is more of an on demand feature that switches on when the application cannot maintain the nominal frame rate expected for the VR display. On a related note, Oculus has also announced Avatars SDK allowing developers to integrate avatars into the VR experiences.
