GLSL Link Errors on using URP: "Constant register limit exceeded" [Linux]

My system setup:
* Ubuntu 19.10
* Geforce 970
* nvidia-driver-435​

Hey everyone,

When using 2020.1.0b3, I get several variations of the following error on loading the example URP project:

-------- GLSL link error: Fragment info
-------------
(0) : error C6020: Constant register limit exceeded at _MainLightPosition; more than 1024 registers needed to compile program
(0) : error C6020: Constant register limit exceeded at _MainLightColor; more than 1024 registers needed to compile program
(0) : error C6020: Constant register limit exceeded at _DrawObjectPassData; more than 1024 registers needed to compile program
(0) : error C6020: Constant register limit exceeded at _AdditionalLightsCount; more than 1024 registers needed to compile program
(0) : error C6020: Constant register limit exceeded at unity_FogColor; more than 1024 registers needed to compile program
(0) : error C6020: Constant register limit exceeded at _CascadeShadowSplitSpheres0; more than 1024 registers needed to compile program
(0) : error C6020: Constant register limit exceeded at _CascadeShadowSplitSpheres1; more than 1024 registers needed to compile program
(0) : error C6020: Constant register limit exceeded at _CascadeShadowSplitSpheres2; more than 1024 registers needed to compile program
(0) : error C6020: Constant register limit exceeded at _CascadeShadowSplitSpheres3; more than 1024 registers needed to compile program
(0) : error C6020: Constant register limit exceeded at _CascadeShadowSplitSphereRadii; more than 1024 registers needed to compile program
(0) : error C6020: Constant register limit exceeded at _MainLightShadowParams; more than 1024 registers needed to compile program
(0) : error C6020: Constant register limit exceeded at _MainLightShadowmapSize; more than 1024 registers needed to compile program
(0) : error C6020: Constant register limit exceeded at _AdditionalShadowmapSize; more than 1024 registers needed to compile program
(0) : error C6020: Constant register limit exceeded at unity_SpecCube0; more than 1024 registers needed to compile program
(0) : error C6020: Constant register limit exceeded at _BaseMap; more than 1024 registers needed to compile program
(0) : error C6020: Constant register limit exceeded at _BumpMap; more than 1024 registers needed to compile program
(0) : error C6020: Constant register limit exceeded at _MetallicGlossMap; more than 1024 registers needed to compile program
(0) : error C6020: Constant register limit exceeded at hlslcc_zcmp_MainLightShadowmapTexture; more than 1024 registers needed to compile program
(0) : error C6020: Constant register limit exceeded at hlslcc_zcmp_AdditionalLightsShadowmapTexture; more than 1024 registers needed to compile program​

This results in glitched graphics (see screenshots below).
This error does not occur in 2019.3.7f1, so I don't think it's a linux issue.
I can also work around this error in 2020.1.0b3 by switching the graphics API to "Vulkan" in the Player Settings.

I attached screenshots comparing the behaviour of both editor versions.

2020.1.0b3 <OpenGL 4.5>:

2019.3.7f1 <OpenGL 4.5>:

2020.1.0b3 <Vulkan>:


I spent some time trying to find causes or an explanation online. Unfortunately, I did not find information that would explain how this error is related to Unity, so I decided to post it to these forums first.
Am I correct in assuming that this is a bug introduced with 2020.1.0b3?

 

It's using URP version 8.0.1.
I've now submitted the bug report for this, Case 1233237.

​

 

Same problem here with Unity 2020.1.0b4.3439 and URP 8.0.1
(Using Ubuntu 18.04.4 and nvidia-430)

I did some tests, and the only materials that are working are unlit ones, all lit materials are pink.

 

Also running into this with: Ubuntu 20.04, Unity 2020.1.0b6.3521, OpenGL 4.5, nvidia-driver-440, URP

 

That fixed the issue for me; Apologies for not noticing there was a newer version available. Thanks!

 

URP 8.1.0 doesn't fix it for me. I still get pink shaders and warnings spam.

Edit: This seems to occur if you have many objects in the scene. When I disable most of them the bug disappears.
Edit: It's point lights with many objects. If I disable all point lights it works.

 

I did. Case: 1262602
Happens with URP 8.1.x, doesn't happen with 9.0.0-35.

 

Did this get fixed? It is happening for me on Windows, GL ES 3.2

 

yeah, we are writing a mobile game, but I found it's a lot easier to test GL ES specific issues in Windows rather than waiting on builds and testing on Android.

 

Yes I recognize that, but for example it helped me last week when debugging why shadows weren't working (inverted Z buffer). So I get what you are saying, but for some issues, it definitely helps.

 

iirc, in this case the issue wasn't reproduced in GL. Well actually now that I remember, the issue turned out to be I was checking for GL ES, not GL ES 3 (GL ES maps to ES 2 in the shader).

Is GL ES just not supported at all on Windows?

 

I was surprised it worked to begin with tbh, but I understand. Thanks.