Quest 3 - Deferred Rendering via PC

Development Platform & Builds XR Development
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1

I am using the Quest 3 - deferred rendering for VR PC.
For some odd reason, I am getting a so called unwanted “mirage” effect.
No mater what GI, Reflection, AA, or Shadow Solution.

It’s a riddle I can’t solve. I switch to Forward Rendering and the “mirage” effect is gone.

But the whole point is to use Deferred Rendering, so I can use Shader Model 6.
Besides, no matter what Shader Domain I use - no reflection, it’s all the same even when using a simple plain material.

  • Does anyone experience similar issues?
  • Any ideas or thoughts what could cause that issue?

Thx a bunch for any ideas, appreciate it!

2

Hi there @BernhardRieder

If you disable screen-space post-process effects, does it still happen?

3

Yes, I killed it all and tested everything separated.
The Mirage effect is extreme dominant as soon as I switch to deferred rendering.

It checked the following:

  • Materials with different Domains (plus Roughness, Normals, Opacity, Translucency, etc.)
  • AA
  • GI
  • Reflections

In the end, I had everything disabled, one light only with one plain material, one solid color.
Same issue - the “mirage” effect is not going away.

Geometry changed from Nanite, to Nanite disabled.

Nothing. I thought perhaps the project file is corrupt, or any other overrides.
So I started a blank VR Template from scratch. Guess what, same issue.

Of course, the unwanted “mirage” effect appears when I load the architectural geometry.
However, I checked if it could be caused by UVW’s as well. Nada.

Also, when importing my geo (static meshes only),not very dense, or complex.
The FPS drops to 30FPS - which is not sufficient, even in unlight mode.

I do have two A6000 - and a very beafy workstation.
Latest Nvidia drivers, etc.

I am running out of ideas… thanks for any hints!

4

I’d suggest using a frame debugger like RenderDoc and looking over the render calls to see where the effect gets added.

Do you have any screenshots videos of how it looks?

5

hmm.. you mean RenderDoc will specifically show me what’s causing the mirage effect?

It’s strange. Even when using the VR Template and switching to DX12 and SM6 - kaboom, you’ll run immediately into that issue.

Not sure if it’s possible to see the mirage effect on a still or screenshot. Because it’s happening when using the VR headset.

6

yes, it has nothing to do with the Screen Space GI. In general, you use DX12 and SM6 - kaboom, you have the unwanted “mirage” effect.

How can we fix this?

7

The effect would have to be visible in the output framebuffer, but RenderDoc could help show where in the rendering process it is added. If it’s a deferred pass, the main render pass, or postprocessing.

If it’s not visible in a screen recording, an option is to film it though the headset lens. It’s hard to give advice on a rendering on a description alone.

8

Some screen shots would be very helpful in this situation.

9

Hey, screenshots don’t capture this unwanted artifact or effect.
Also video capture via the VR Headset isn’t cutting it.

I was prepping a simple VR Project file, that includes basically the default VR-Template, but with the Project Settings for PCVR, DX12 and DLSS.
You can Download from here. (290MB)

Screenshot attached:

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HighresScreenshot000001920×1080 56.7 KB

Unreal Engine 5.4.4
RHI: DX12
Deferred Rendering, DLSS

Issue is consistent:
You can’t use DX12 for VRPC without running into the so called “mirage” artifacts.
The scene provided is the VR-Template with one Direct Light only and highlights this major issue.

Curious about everyone’s else test results, thoughts and ideas.
Cheers