Access lightmap index in shader

Is there a way to access the lightmapindex in a cg shader? Using "unity_Lightmap" gives me the lightmap texture itself, but I need the index so I can use it to lookup a value in an array.

 

Did you ever find a solution to this? A shader property set between batches would be really useful.

 

Hi,
You can get it in C# script and pass the value to the shader?

 

I don't think I ever found a built in way.

 

any solution ?

 

Bump

 

Memo :
- Surface : https://forum.unity.com/threads/sampling-lightmap-in-surface-shader.185714/
- Vertex Frag : https://gist.github.com/jimfleming/5937437