I present you a pure shader based cube environment mapping. It might be useful for those who, for whatever reason, does not have "samplerCube" texture type support in their engine or want some more flexibility or customization for envmaps. It is a tiny bit slower than the proper version and mip-mapping is not working well, so it is pretty much useless.
This paper helped me a lot: http://www.cs.wustl.edu/~cmg/content/papers/jgt2007em/jgt2007em.pdf
Anyways, the input can be 6 separate textures or cube environment map Blender style. A standard OpenGL style alignment is on the way.
screenshots are in previous post :)