There was this discussion on another forum, which prompted this short entry:
 

There was this feature, most recently re-implemented into the project (a separate excursion), that provided a cinematic transition between locations; which in return gave more attention to the background. Which was a …

You can also have a look at mapping spheres to 2D textures for single pass shadow-map rendering. Last time I checked it is also quite a bit faster than cube-map shadows.

What you get is basically an UV unwrap of the sphere onto a texture, which you then write your depth info to.
When you need to samp…