Surface Shaders: Ignoring clip() during shadow casting, respecting it during shadow collection

Hello, I have a cube with a surface shader that runs

clip(IN.uv_MainTex.y > 0.5 ? 1 : -1);

as a simple clipping test. Naively the shader produces the following:



This is resolved by adding

addshadow

to the #pragma line:



...which respects the clip() during shadow casting and collection. However, the output I want is as below:



Where the clip() is ignored during shadow casting and shadow collection (the above image is created by having a duplicate cube with the default Unity material and Shadows Only set). If this seems a bit odd, my use case case is to make objects between the player and the camera use dithered transparency to avoid occlusion. Ideally, the shadows would remain to make the dithering as seamless as possible. Using the frame debugger, we can see that during shadow collection the cube occludes the floor behind it.

...so while I can get the desired effect using duplicated meshes, if there's a straightforward way to do this all in-shader I'd prefer that to make life easier in the long run (rather than having to manage duplicating/destroying new objects etc).

Thanks for any answers,
Erik

 

The shadow caster pass gets used for both the camera depth texture, used for the shadow collection pass as what is being cast into. I posted about something related to your question here:
https://forum.unity.com/threads/surface-shader-offset-shadows-on-z-axis.877618/#post-5775346