I did that in the previous shadowrenderer.
But the probelem is, that the Terrain does not have a resolution
high enough, to make the "curves" in the terrain look smooth.
So when the part of the terrain has a thin angle, so that it is almost in the shadow,
it will be drawn darker. But this makes hard edges between the faces of the terrain,
looking unrealistic.

Thats why I want only tweo choises "dark" or "lit". The smoothing removes hard edges in the
postprocessing.

The "fine" shadow/light differences will then come from the dynamic lightning of the terrain.


in the video you can see that the terrain looks quite nice ingame:

http://de.youtube.com/watch?v=hyRrjEBkA6g



Here with wather. Its quite Flat, so i have to look for a shader that makes it look good, but
does not drain performance.