Fictional details in textures

[AstroChara]

Currently there is a push for realism in Celestia - with care being taken to implement various features that promote this goal, such as realistic colors for planets and stars, as well as limb darkening for a recent example.

In light of this, I noticed that Celestia contains a fair amount of fictional details used to fill gaps in our knowledge of the universe, such as the unmapped regions of Triton or substructures within Haumea's rings. Contributors appear to have different standards regarding them, so I think this topic is worth discussing about.

[AstroChara]

My personal opinion on this subject is that we should minimize the use of fictional details, especially for the default settings. These fictional details, while they help make objects appear prettier and less jarring, introduces possibility of such features being confused for real details by inexperienced users who do not have understanding of how the program works (speaking from experience).

My main suggestion is about making limit-of-knowledge textures the default textures if possible, while fictional details appear in alternative textures, although I am less certain about this for completely unmapped objects (such as asteroids or exoplanets) and stars, which may still use fictional details by default. I think it is also a good idea to have discussions whenever we implement fictional details in order to make these fictional details as realistic as possible.

[SevenSpheres]

For the ring textures (Haumea as well as Chiron and Chariklo), if you want to create ones based only on real data like you did for Quaoar, those can be used instead of the fictional ones currently present.

[ajtribick]

While I think it would be nice to have limit-of-knowledge as the base texture and fictional as an overlay, the Celestia codebase hardcodes special behavior around the "limit of knowledge" name, so doing it the other way round would break compatibility with 1.6.x. And at the moment, people seem to be opposed to using 1.7.x-only features in this repository.

[AstroChara]

For the ring textures (Haumea as well as Chiron and Chariklo), if you want to create ones based only on real data like you did for Quaoar, those can be used instead of the fictional ones currently present.

We have one from Project Echoes, and it's basically a solid color file. If no one has objections I think we should use it and make fictional one into an addon. Or perhaps use an improved version of that for an addon.

[AstroChara]

While I think it would be nice to have limit-of-knowledge as the base texture and fictional as an overlay, the Celestia codebase hardcodes special behavior around the "limit of knowledge" name, so doing it the other way round would break compatibility with 1.6.x. And at the moment, people seem to be opposed to using 1.7.x-only features in this repository.

The change I proposed (limit of knowledge as base) would simply be based on the codebase, AKA the 'full textures' could still contain fictional details, and the lok overlay is instead on by default. I do prefer your suggestion because I am unsure how a partially fictional texture can be created while making sure that every pixel not obscured by lok are real, but it seems less problematic. That said, I am open to dropping compatibility with 1.6.X, as 'patches' are likely fairly easy to make (for example, you might make the fictional texture on a different layer from the real texture (and I think you really should), and 1.6.X-compatible textures can simply be made by saving different layers).