Bug QUEST 2 Render issues left eye when using grass (compute)shader.

Hi all. I am using a grass solution created by MinionsArt in my VR game for Quest 2 and added the work to make it work with singlepass rendering. However when I build my game and load it on the Quest 2 the moment the grass is enabled on the build the left eye seems to start glitching when I move my head around. The image seems to jitter a bit (this does not show up on a recording).

I have added a zip with the source code used and a image I created in photoshop to show the effect while moving around.

I hope someone is able to help me find a possible solution so I can have beautiful grass! I am using 2021.3.17f but also tried .16f. I also tried enabling / disabled all graphics and it is really the grass creating my issue.

Project settings:

Spoiler

Render pipeline: URP Version 12.1.8

URP Settings:
Depth texture: Enabled
Opaque texture: Disabled
Terrain holes: Disabled

Quality:
HDR: Enabled
MSAA: 4x
Render scale 1
Upscaling filter: Automatic

Lighting:
All lighting (Main and additional) is disabled.

Shadows:
Max distance: 0
Working unit: percent
Cascade count: 1
Last border: 20
Depth bias: 1
Normal bias: 1
Soft shadows: Enabled (Dynamic shadows are not really used)

URP Forward renderer settings:
Opaque layer mask: Everything
Transparent layer mask: Everything

Rendering path: Forward
Depth priming mode: Disabled
Depth texture mode: After opaque

Native render pass: Disabled
Transparent receive shadows: Disabled
Post processing: Disabled
Overrides stencil: Disable

Quality settings:
VSync count: Dont sync
Teture quality: Full res
Anisotropic texture: Disabled
Texture streaming: Disabled

Particle raycast budget: 64
Billboard face camera position: Disabled
Shadowmask mode: Shadowmask
Buffer size: 16

XR Plug-in management settings:
Render mode: Singlepass instanced / Multi-view
Depth submission mode: None
Low overhead & phase sync: Enabled


OVR Manager settings:
Use recommended MSAA Level: Enabled
Monoscopic: Disabled
Min render scale: 0.7
Max render scale: 1

Build player settings:
Color space: Linear
Auto graphics api: Disabled
Graphics api's: OpenGLES3
Multithreaded rendering: Enabled
static batching: Enabled
Compute skinning: Enabled
Graphic jobs: Disabled
Texture compression format: ASTC
Normal map encoding: XYZ
Lightmap encoding: High quality
Virtual texturing: Disabled
Scripting backend: IL2CPP
Shader precision model: Use platform package
Keep loaded shader alive: Disabled

 

I did not have a any luck yet fining a solution, turning the instance count to 1 on DrawProceduralIndirect did nothing to resolve my issue.

 

Anyone who might be able to help us with this?

 

Might have the answer, but I am running on limited knowledge of your VR build settings. This issue appears when the shader is not properly supported by Unity XR with their either URP or HDRP as shaders are rendered differently using VR. Getting around this requires extended coding knowledge and you have to know what you are doing when developing this.
I can only refer back to this post without knowing what your settings are : https://github.com/ColinLeung-NiloCat/UnityURPUnlitScreenSpaceDecalShader/issues/13
There might be some more good explanations there to why your problem is appearing.
Best of luck!

 

Thank you so much for answering! Good note that my settings might influence behavior so let me share these here as well (I will also update the original post).

Render pipeline: URP Version 12.1.8

URP Settings:
Depth texture: Enabled
Opaque texture: Disabled
Terrain holes: Disabled

Quality:
HDR: Enabled
MSAA: 4x
Render scale 1
Upscaling filter: Automatic

Lighting:
All lighting (Main and additional) is disabled.

Shadows:
Max distance: 0
Working unit: percent
Cascade count: 1
Last border: 20
Depth bias: 1
Normal bias: 1
Soft shadows: Enabled (Dynamic shadows are not really used)

URP Forward renderer settings:
Opaque layer mask: Everything
Transparent layer mask: Everything

Rendering path: Forward
Depth priming mode: Disabled
Depth texture mode: After opaque

Native render pass: Disabled
Transparent receive shadows: Disabled
Post processing: Disabled
Overrides stencil: Disable

Quality settings:
VSync count: Dont sync
Teture quality: Full res
Anisotropic texture: Disabled
Texture streaming: Disabled

Particle raycast budget: 64
Billboard face camera position: Disabled
Shadowmask mode: Shadowmask
Buffer size: 16

XR Plug-in management settings:
Render mode: Singlepass instanced / Multi-view
Depth submission mode: None
Low overhead & phase sync: Enabled


OVR Manager settings:
Use recommended MSAA Level: Enabled
Monoscopic: Disabled
Min render scale: 0.7
Max render scale: 1

Build player settings:
Color space: Linear
Auto graphics api: Disabled
Graphics api's: OpenGLES3
Multithreaded rendering: Enabled
static batching: Enabled
Compute skinning: Enabled
Graphic jobs: Disabled
Texture compression format: ASTC
Normal map encoding: XYZ
Lightmap encoding: High quality
Virtual texturing: Disabled
Scripting backend: IL2CPP
Shader precision model: Use platform package
Keep loaded shader alive: Disabled

 

After some thought I find it weird that it cannot show up on a recording, which means it only shows in the headset.. Or? There's different ways to record Quest image output, either show both eyes, 1 eye or directly from the computer. All in all I think the shader is just not properly coded to support VR/ your headset. If you are trying to use a shader made by someone outside of Unity I would contact them and ask for support to make it work with your project.

 

I tried contacting to no avail and tried converting the shader myself. It seems to only happen on the quest 2 native build version indeed. I will try to record the left eye natively and hope to capture it that way.

 

Study their solution/logic and read up on how shaders are implemented for the Quest2 and you might just fix your problem. Sounds like a pain in the *** but I don't think this is anything else than just some fiddling about and you'll make it work. if not, make your own shader that will work for you!

 

I will do that, I hoped adding the single pass support would be enough hahaha

 

I have found a solution for the issue with the compute shader by upping the instance count to two, but now a weird screen tear effect is present with the object on.