Fix this elephant in the room

[AnotherCommander]

We've had this one for millennia. Appears with crescent planets when there is atmosphere with cloud layer. Apart from those "steps", lighting misbehaves as well when moving the camera.

Fixing this one alone would be a great graphics boost.

[oocube]

I checked on my Ubuntu 24 LTE using Oolite_dev_1.93.0.7781-260308-7f79851-x86_64.AppImage and cannot see such effects. Maybe just on Windows, or just on HDR?

Nevertheless, if it can be improved, here is my +1.

[phkb]

Not just HDR. I see this on regular SDR. Don't know about the Windows/Linux thing though.

[AnotherCommander]

Taking the image in this shot from the Screenshots thread: https://bb.oolite.space/viewtopic.php?p=300224#p300224 and just raising gamma a tiny bit (because cbr likes his screenshots very dark) reveals the issue is present also with Linux. Here is that shot at more normal brightness levels:

I think the shot was taken with 1.90 but since the rendering code for planets was not changed for 1.92.x this is still a valid comparison.