A couple of years ago, we released Asynchronous Spacewarp (ASW) for the Oculus Rift PC runtime. ASW technology works behind the scenes to effectively give our users “free” CPU and GPU upgrades, to provide higher-quality VR on lower-spec hardware. ASW activates as the headset rotates (3DOF), predicting head movement, extrapolating and smoothing frames, and reducing judder to make VR more comfortable.
Until now, ASW has been self-contained in the runtime, where it just works—but we knew it could be better. Today, we’re excited to release the first major upgrade to ASW. ASW 2.0 builds on our previous version, activating to support headset performance in a full 6DOF space, accounting for depth and rotation. ASW 2.0 combines ASW with an existing experimental technology, Positional Timewarp (PTW) to take our PC runtime prediction accuracy to the next level and further boost app performance and frame rate.
The strengths of ASW 2.0 are best seen in several situations:
ASW 2.0 asks developers to expose depth information. With the Rift system interface Dash, the Oculus PC runtime already uses PTW to smooth performance, blending the Dash interface over an app’s depth-composition layers. As such, 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. As more apps provide this information, ASW 2.0 support will become increasingly ubiquitous.
For applications that don’t provide the necessary depth data, the Oculus PC runtime will revert to ASW 1.0. However, it’s easy for developers to patch their applications should they choose to activate ASW 2.0 while also activating depth-composition with Oculus Dash.
Even with all of the advancements in ASW 2.0, there may be some instances where it doesn’t work perfectly. That’s why we always ask developers to optimize their VR apps to be able to render at the native HMD refresh rate. Given the wide range of PC hardware capable of running VR, features like ASW 2.0 can help smooth out bleeding-edge VR experiences for both end-users and developers.
We’re excited to bring ASW 2.0 to the Rift community and can’t wait to hear your feedback. There’s no shortage of possibilities for future improvements as we continue to push the envelope of ASW and related techniques. Stay tuned for more on this space.