[Plugin] Leap Motion - Event Driven

[getnamo]

@martin_vr;641935

Hi ,

In my setup there seems to be quite a latency before the hands correct their position when moving the HMD sideways or up and down. As a result they have hard time staying in place. They jitter. In the LeapMotion vizualizer there’s almost no latency or jitter.

Could it be something in my UE4 config?

My setup: Ue4.14.1 / Rift CV1 / Leap controller firmware v1.7 / Orion 3.2.0 / GTX1080

I tried a screen recording but noticed that in the VR Preview window there is no latency. It’s only in the HMD.

This has to do with lack of proper timewarp support, currently tracked as an issue: https://.com//leap-ue4/issues/9.

Modern HMD software stack is late updated in the render thread with a fair bit of magic to make sure the perceived latency is 0. Leap timewarp is the attempt of ensuring the latest available leap tracking data is orientation warped by the hmd rotation that happened since that sample was taken.

I did make an attempt of adding this feature, but so far it becomes unstable when you overdrive it (real jitter) to get 0 perceived latency. Something is still missing.

This is the major holdout for the UE plugin in the current state and I want to take another look at it, likely when I’ll do the modern rewrite for this plugin. If you feel like you can help, by all means take a look at the source ! Perhaps someone will spot why our version of timewarp is jittery while Unity’s is not.