Normal maps would work on landscapes and it has been done before - but there is still the problem of the low poly edges on the horizon. I think parhaps what Dreamora meant was that the polygon resolution of the landscape of sswifts terrain engine was too low to make a good normal map from. However, you can always add detail over the top into the normal map, or smooth over the result - but at the end of the day, using a normal map means you can a lot use less poylgons and achieve the same result (Discounting the edges).
I think for normal mapped landscapes to work, you'll also need some way of keeping the edges of the horizon quite high poly and take the camera angle into account. If your terrain is patch based, one way of doing this is pre-determine how complex a patch is by evaluating the differences in the patch heights, then when choosing the correct LOD at render time factor in the complexity value.
I think for normal mapped landscapes to work, you'll also need some way of keeping the edges of the horizon quite high poly and take the camera angle into account. If your terrain is patch based, one way of doing this is pre-determine how complex a patch is by evaluating the differences in the patch heights, then when choosing the correct LOD at render time factor in the complexity value.