Skybox might be to small for the increased terrain height range

[FeXoR]

This screenshot from Atlas suggest that the skybox might not be big enough for the increased terrain height range: ​http://wildfiregames.com/forum/uploads//monthly_09_2015/post-14196-0-00430700-1443195625.jpg

[elexis]

Also it often becomes possible to see the black area below the skybox, which is bad for promotional screenshots.

(There are also other methods to draw the skybox. For example it can has the size 1x1x1, but be rendered independent of the world position of the camera with a different openGL projection, so that the skybox appears infinitely far away. If good textures are chosen, the box shape of the skyset will also become unnoticeable.)

[elexis]

The catch is that the player expects black and not a blue sky at the ground level where the map ends.

So the skybox could become a threeway option (disabled, partial, complete) so that it could be enabled manually for screenshots and when cinematic paths are active, the skyset could always be rendered completely.

Another option might be to just change the size of the skybox so that the map border is always black while the skyset is always visible when viewed from the currently problematic angles (don't know if that's feasible though).

[Vladislav Belov]

In 22039:

Remove hardcoded SkyBox sizes and use the infinity sky. No we render
the skybox at the current camera location, so that the skybox appears
indefinitely far away. Refs #3458.

Reviewed By: wraitii
Tested By: elexis, Stan
Differential Revision: ​https://code.wildfiregames.com/D1683

[Vladislav Belov]

Now the sky is in infinity, so we won't have problem with the sky & terrain intersection.