Some side work with atmospheric acattering. I tried to implement alternative code, which performs scattering integration on-the-fly in the planet/sky shader, rather than use precomputed scattering tables (textures). It solves a lot of issues with artifacts and inability to change such paramters as atmosphere opacity (optical depth). The drawback is a low performance, so some hybrid method should be used. Probably this method will be used with 3D clouds anyway, because the old code is somewhat incompatible with them.
New code features the ozone layer. Compare with and without the ozone:
Change of atmosphere density: 0.1 - 1 - 3
Artifact-free sunset in autoexposure mode:
And a killer feature: I can specify a custom density profile for any of component (Rayleigh, Mie (aerosols) and ozone). Here is a Mie scattering turned into a haze layer at some height. This will be very useful for Venus and Titan. Screenshots are showing descending through the haze layer. It is dark here, but can be of any color: