Quote:I guess it is not a good idea to use skyboxes and usual water rendering (too expensive), because user never sees sky and on large terrain you must save resources.

I slighty disagree [smile]

1. Yes, you don't need a sky box/dome but you can still benefit from one. Water reflects, so you indirectly see the sky as a reflection in the water [wink]

2. Yes, full blown fresnel reflect/refract water might be overkill but the screenshots you've posted probably use the same basic theory. They've just dropped less significant terms (refraction is horrifically overused in some games to give a "liquid glass" look and feel) and tweaked others.

3. Yes, but with a good resource manager you don't need to worry too much. Especially in the days of multithreaded architectures you can get very good results with a paging/swapfile approach - good performance, good quality and good resource requirements.

Quote:how is the color of wave calculated? As I am thinking, it has something to do with the bump normals (like, the colour of the pixel is calculated by a direction of the normal e.g. if the normal is pointing to the left, the pixel is white, but if the normal is pointing to the right, it is blue (first picture)). Or maybe there is used something like a 2D sky texture for the vawe colur calculation?

This sounds like the right sort of thing. It will be a combination of standard lighting (e.g. the bright pixes are facing the light source) and a reflection model where it's looking up the colour of the sky texture. Then there appears (from the 1st image) to be a standard reflection of the cliff/objects factored in as well...

hth
Jack