Strange compilation error URP Lit shader

Unity Engine
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1

I am using Unity 2021.3.21f1 and URP 12.1.10
I slightly modified the standard URP Lit shader. I managed to fix many compilation errors, but I can not fix one error for several days. Moreover, this error does not occur during normal compilation in the Uity editor - IT OCCURRS ONLY WHEN BUILDING THE WHOLE PROJECT.
The error is like this:
Shader error in ‘GK/URP_Lit’: Fragment program ‘DepthNormalsFragment’: Unrecognized sampler ‘sampler_basemap’ - does not match any texture and is not a recognized inline name (should contain filter and wrap modes). at line 266 (on d3d11)

As you can see, the error is in the ‘GK/URP_Lit’ shader and is related to the ‘DepthNormals’ pass, specifically in the fragment program ‘DepthNormalsFragment’, which is located in the GK_URP_LitDepthNormalsPass.hlsl file at the very bottom.

This is all clear. But there are questions.

  1. There is no ‘sampler_basemap’ sampler in this shader, there is only such ‘sampler_BaseMap’.
  2. If line 93 :
    float3 normalTS = SampleNormal( uv, TEXTURE2D_ARGS(_NormalMap, sampler_BaseMap), _NormalMul );
    replace with this
    float3 normalTS = float3(0.0, 0.0, 1.0);
    then the ERROR DOES NOT occur, and a little higher in the DepthNormalsFragment() function there is line 77
    Alpha( SampleAlbedoAlpha(input.uv, TEXTURE2D_ARGS(_BaseMap, sampler_BaseMap)).a, _BaseColor, _Cutoff );
    it also uses sampler_BaseMap and there are no errors!
  3. Another ‘ForwardLit’ pass also uses the sampler_BaseMap sampler for _BaseMap, _NormalMap, _MetallicMap, _RoughnessMap textures and everything is fine - no errors.

You can, of course, create your own sampler for _NormalMap and use it, but I want to figure out why sampler_BaseMap works for _NormalMap for one pass, but does not work for another pass.

Also noticed one not clear moment.
For the ForwardLit pass in the Varyings structure (file GK_URP_LitForwardPass.hlsl) for uv, TEXCOORD0 is used:
float2 uv : TEXCOORD0;
And for the DepthNormals pass in the Varyings structure (GK_URP_LitDepthNormalsPass.hlsl file) for uv, TEXCOORD1 is used:
float2 uv : TEXCOORD1;
Why?

8954163–1229598–Shader GK_URPLit.unitypackage (17.9 KB)

2

Hi!
This can happen if the compiler decides that the texture for this sampler is not used in the pass.

3

At first I also thought that the compiler for some reason for the DepthNormals pass does not use the _BaseMap texture, and therefore the sampler_BaseMap, which is why this error occurs.
But why is there an error like this:

Alpha( SampleAlbedoAlpha(input.uv, TEXTURE2D_ARGS(_BaseMap, sampler_BaseMap)).a, _BaseColor, _Cutoff );
…
float3 normalTS = SampleNormal( input.uv, TEXTURE2D_ARGS(_NormalMap, sampler_BaseMap), _NormalMul );

and there is no error:

Alpha( SampleAlbedoAlpha(input.uv, TEXTURE2D_ARGS(_BaseMap, sampler_BaseMap)).a, _BaseColor, _Cutoff );
…
float3 normalTS = float3(0.0, 0.0, 1.0);

I wrote about this in the first post in question number 2. Both variants use sampler_BaseMap.

4

I think the second snippet doesn’t use neither _BaseMap nor the sampler_BaseMap, so there’s no errors.

5

Maybe. We don’t know exactly how the shader compiler works, so, as I wrote above, I will create another sampler_NormalMap sampler and use it.
Thanks for the comments.