Extract lightmap from blocks

Hi,

I need a method to extract the lightmap of blocks.
Because I don't know any function to access the lightmap of a block, I have to use a shader. My shader knowledge is ... äh weak. I only wrote Post Porcessing shader in combination with bmap_process. But I can't use this either, because blocks are not exposed as entities, arn't they?
I need to copy the lightmap information into another bitmap and I have no Idea about object shaders.
Any tipps?

Greetings,
patrick

Ok, guys, I figured it out. I simply used the pixel shader part to copy the information into another bmap.

This is the same requirement here
so the pixel part is the trick, I will try that