Objects drifting when rotating head with Morpheus

Hello,

We’re developing PS4 VR game with UE 4.10.0 and PS4 SDK 3.0.

However, we met a tracking problem.
We have an FPS actor (VRDebugProprs) showing at left-top corner of viewport, following HMD’s position and rotation.

When rotating head with HMD, FPS actor can’t follow with HMD perfectly. It seems moving slower than HMD.

We tried another empty project with only single table. table seems drifting like a pirate ship when rotating head, too.

Our FPS is around 60.
Are there any suggestions? Thanks.

Morpheus uses temporal reprojection techniques similar to Rift and Vive. Basically, if your game is not running at native headset refresh rate, headset driver will take most recent rendered image, and distort it so that it appears to be rotating along with player’s head movements.

You can read about it here: http://ps4daily.com/2015/03/ps4-vr-headset-120-fps/

However, as you have noticed, one of limitations of this technique is that objects which are locked to player’s view (like a visor above their head) will appear to lag behind rotation of player’s head. There is no way to avoid this except to run at 120hz.

(Actually, there may be other ways, but I am not familiar enough with PS VR to recommend anything. If you didn’t already know how temporal reprojection works, there is no chance you would be able to implement this for your game.)

I suggest you change your game so that there are not any objects in your game world locked to player’s head rotation. There is probably nothing else you can do.

Thank you for reply :slight_smile:
I understand limitation of reprojection now. (Object can’t move & head can’t move)
My apologies, drifting isn’t specific enough for this phenomena.
It’s not only just blurred, it seems moved much slower.
Something like lag.
Even static table also affected.

I tried to disable reprojection. Debug text is still drifting & lag.

Sorry, I don’t think I can help you any further. By way, I believe developer agreement for kit doesn’t allow too much specific information to be discussed publicly, so you might not get much help here.

Hi Katalla,

As cancel mentions below, you need to be careful to not break developer agreement with Sony. It doesn’t look like you have so far, but I would encourage you to bring this question to our private forums for PS4 development or Sony’s Morpheus forums. generally wants all Morpheus support questions on their forums.

I believe developer agreement for kit doesn’t allow too much specific information to be discussed publicly, so you might not get much help here.