Sample "unity_lightmap" outside the fragment shader

Hello!

For my current work, I need to iluminate procedual geometry (gras). By channeling the UV2 coordinates way trought the pipeline (vertex-> hull -> tesselation -> domain -> geometry -> fragment) and finally sampling them inside the fragment shader like below I made very good results.

Code (csharp):

1. DecodeLightmap(tex2D(unity_Lightmap, i.lightmapUV));

It would be sulficiant for me to sample the lightmap inside the domainshader or atleast the geometry shader. But using tex2Dlod like below:

gives the error

It seems to me that "unity_Lightmap" is simpily not defined outside the fragmentshader, Is this a bug? Or is it technically not possible to accsess the texture outside the fragmentshader (I can't really image that)?

TL;DR "unity_Lightmap" can't be sampled outside the fragmentshader. Why?

 

Running into the same problem. Bump.

 

I know this is old, but it is the only thread I was able to find when looking into this. I was able to sample the lightmap in the vertex shader with this macro:

Code (CSharp):

1. o.ambient = UNITY_SAMPLE_TEX2DARRAY_LOD(unity_Lightmap, uv.xy, 0).rgb;

 

Lifesaver, thank you for sharing this.
I was wracking my brain trying to figure out how to make unity_Lightmap and tex2Dlod talk to each other, so that I could sample Unity's lightmaps as vertex colors. Just had to make sure that the right UVs were being passed. (in my case, I had to remove ".rgb" from the end for some reason.)

 

unity_Lightmap.SampleLevel(samplerunity_Lightmap, o.uv2), 0.0);