Requirements for Tyler on the sphere

[asinghvi17]

• Intersect the viewing frustum with the sphere and retrieve the area of interest
• potentially center the camera in Google Earth style rotation so that you cant translate, then just use FOV and view_direction to compute the bbox from the spherical cap

[asinghvi17]

The second point is done in my GlobeAxis PR to GeoMakie. The first remains to be solved. One interesting resource might be https://stackoverflow.com/questions/13541526/hierarchical-frustum-culling-of-sphere-tiles.

Maybe some plane-sphere intersections can help with this? But we would need to know how dense to make each area of the globe. It's tricky for sure.

A good enough compromise for now is simply getting the viewed lat/long back, and using the "radius" from (0,0,0) to determine how much detail we need. That would work under the assumptions that: a. The camera always points towards (0, 0, 0) b. The FOV is circular, i.e., a cone that forms a spherical cap when it intersects with the globe (it's not, but that's an OK approximation - not too wasteful for now)