[4.19] Planar reflections performance in VR

Development Platform & Builds XR Development
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1

Hey all, i have issues getting the planar reflections to behave as usual.
My scene renders well in 4.18 + VR but with just “switching” the unreal version i cant even get below 30 ms anymore.
The gpu profiler tells me a frame needs below 7ms to render so it must be some kind of misconfiguration or bug affecting the game thread or something else. When i remove the planar reflection it returns back to normal.

Steps to reproduce:
0. Download Project files to skip the following steps: https://we.tl/6TI8sjgDk1

  1. Create Project with Realistic Render Template for each version (4.18 and 4.19)
  2. Enable Forward Shading, MSAA, Global Clip Planes
  3. Let the shaders recompile
  4. Add Planar Refleciton to scene and change the floor material to be able to recieve it.

5.Watch in VR
Result on my 1070 Laptop:
4.19 45fps or less
4.18 90fps

(i tought maybe the new resolution thing might be the case but it is still visible with r.screenpercentage 130 in 4.18 and vr.pixeldensity 1 on 4.19)

2

Got same problems in my project, tested on Geforce 1070 and 1080. Hope someone at Epic will notice this bug

3

Same problem for me as well. I have no idea how to fix this.

Is there a useless solution on how to fake a planar reflection?

4

Hey all, i found the bug in 4.19. Just move the Screenpercentage to 100 on the planar reflection and there you get 90fps and now frame issues (as long as your hardware can handle it) but anything below 100 and even 99 kills the performance!!!

FIXED IN 4.20

5

NOT fixed, same issue on 4.22.3
Same on Oculus SDK 1.36 and 1.40

Kill the performance even when not visible and at 10% screen percentage, and even at 100%
It was not the case before on 4.21