I have been looking at the code a bit, and if I understand it, from what I see, the tiles loading is designed for object being not too far from the ground, I mean real flying object like the SpaceShuttle right? If yes, I'll be interested to improve it with some exact calculation in spherical geometry, for me that could be some doable project for learning nasal. Is there anything I should know before trying to do so?
To say it bluntly - the whole of Earthview is designed to be seen from low orbit - there's a whole host of things which you would not do from far away (loading 16k textures for starters to see their lowest mipmap levels only
), then having a separation between clouds and terrain which leads to z-fighting,...)
You should know that it's a pretty delicate balance just how and when to load things - if you end up loading 'too much' with 16k textures, you drive even a well-equipped computer into swap - if you load 'too little', so see temporary gaps.
Change at your peril, there's quite a number of ways to get this really badly wrong.