Render Sky Dome

[ataulien]

Gothic 2's sky rendering is a bit more sophisticated that what Gothic 1 did: Instead of rendering a plane, it uses a Skydome and an additional layer of clouds. This has been implemented in REGoth before, so the old implementation can serve as a reference:

https://github.com/REGoth-project/REGoth/blob/master/src/render/SkyRendering.cpp

The dome-mesh can be found in the games files if I remember correctly