dabulla
commented
4 years ago Which Qt Version did you try? They optimized latency of Qt3D recently, potentially removing more than one frame lag (I did not yet try Qt5.15). Lag/Latency is really a huge issue. I think it got better over time - or maybe I'm just getting immune to the lag.
It has been some time, that I worked on this but I try to recap what the state of this is:
- I tried different timing solutions to get rid of the lag using the RenderControl.
- I tried changing the timestamp for predicting the head-pose as a workaround. It does not solve the issue and introduces weird miss-predictions/over compensation.
- There is a way for Qt3D "Aspects" to add dependent aspects. Aspects execute in different Threads and I suspect, that the Head-pose is calculated after rendering resulting in at least one frame latency. With "addDependency" Aspects will be executed before certain other aspects when rendering. Sadly, there is no way to add a dependency to the RenderAspect or to "prepend" an aspect just before rendering.
Recently on twitter I saw Qt Quick 3D supporting VR, maybe this will replace my project here sooner or later.
However, I'll work on this project in the next months. But I'm not sure how far I get with it.
mean-ui-thread
I tried your example with the OculusSDK. Recompiled libOVR.lib with
/MDand/MDd, Also had to change Windows 8.1 SDK to Windows 10 SDK because I don't have Windows 8.1 SDK installed, modified yourvr-sdks.prito disable OpenVR (not using it at the moment), made sure the OculusSDK paths are pointing to the correct location. Modifiedmain.cppto requestOculusSDK. It builds, and it runs. So far so good!However, there is a huge head tracking lag when I pivot my head from left to right. I tried compiling it in release but it doesn't seem to make any difference at all. The lag is quite significant: it feels at least a quarter of a second behind. Any idea?
Thanks!