Render to texture (realtime) for GLSL ?

After it took me an entire evening only to find out how to adapt a single shader to work flawlessly in the BGE i can’t find info on my following question.

To complete a mirror, ice, water,ocean shader i would like to know how i render to a target in BlenderPython.
Or do i have do dive to opengl level? Any hints? If somebody wants to tell me, that this is not possible please mention the obstacles.

BTW, who has tried some development with GLSL shaders in Blender yet?