This has always impacted the realism of flight simulators, in my mind - due to performance reasons, you're always flying around in some pea-soup like fog. At altitude, you can easily see hundreds of miles in clear weather, but I haven't seen any flight simulator that comes even near to being able to render out to those distances.

I believe there are two problems in flight simulators:

- insufficient precision of OpenGL 32-bit floats in Earth-scale computations. If you want to render the whole Earth, you'll find that at the ground level your precision is only 16m resulting in jittering as you move. This was usually solved by "zoning" and local coordinate systems, hence it was easier to deal with a smaller set of ground "tiles" and haze out the distant ones. Having said all that, nowadays you can use vertex shaders to simulate 64-bit (or rather 56-bit) precision and get around 1cm resolution at any distance

- the need to have various LODs that include curvature of the Earth with significantly increased error tolerances, which in turn increases memory consumption. Again, nowadays should be no longer an issue given entry-level GPUs having 1GB of RAM and geometry shaders

> due to performance reasons, you're always flying around in some pea-soup like fog

In fairness, this is also the case of 90+% of real-world flights I partake in..

Yes I believe you make a valid point. However the point of the tech demo was to show off the LODing, and the fog distance in my opinion was way too close, thus inbiting the work the author had done.