Allow `Sky fog blending` to function without fog needing to be enabled

[Peregrine05]

Fog can reduce performance if it is enabled, so it would be nice to be able to use the sky-fog blending to change the sky color somewhat without a significant performance cost.

At this point, it might be reasonable to change the name of the control.

[leMaik]

How would sky fog blending possibly work without fog?

[Peregrine05]

This sky fog "blending" has always appeared to me to be a simple color overlay applied to the sky that decreases in intensity with increasing altitude above the horizon, because it acts completely independently from the actual Fog density, and because the actual fog does not have any observable effect on the sky itself. If that is so, then it should be possible to make this sky fog "blending" function completely independently from fog itself actually being enabled.

[jackjt8]

This is certainly a weird case.

I understand what @Peregrine05 is stating as I have experienced it first hand; The "sky fog" simply appears to be a colored gradient overlay that just depends on the fog being enabled and the color of the fog; The fog density has no impact on the appearance of the sky fog which it really should. So on one hand allowing people to freely use 'Sky fog blending' or rather some derivative of this option with a different name and probably it's own color controls makes sense. Sure people can just use a really low value for fog density (ie 0.000001) just to be able to recolour a skymap a touch... but then you need to deal with the performance reduction from having fog enabled.

On the other hand..? Maybe we do need to figure out why the fog density is not being applied to the sky.