What's so great about them... Not much. Don't take it seriously. It's not a complete game. Just that a 15Km square with decent texture for a flight sim (brillant idea BTW) + code for LOD models + retarded AI + minimal GUI + code for cam placement (gravity+never get out of terrain bounds), runs pretty good with Irrlicht/winXP/OpenGL. All I can say.
Now where does this 15Km value come from I can hear him say.
256X256 heightmap scaled 2048X2048 = 524288 units square.
Assuming a 1m80 tall person is 60 units (see reference perso model), 1 unit = 3cm.
Thus a square side represents 15728*3/100=15728 meters.
Well, after Belfegor suggested flight sim, I thought terrain doesn't need so many polies, and increased terrain scale from 1024 to 2048. Result: it looks the same, but terrain polies budget falled to 2000/4000, allowing to increase FarValue and FogEnd, while gaining FPS at higher screen resolution. Incredible. This information is probably constructive for people who read us. Kudos to Irrlicht LOD for terrain. Not to mention flat areas will drastically reduce polies budget for terrain.
All what is spared here will allow high-detail models, slicky effects, and keep some left for network layer.
At the moment there is only one heightmap. This is main problem. At some point HDD space will say "no" and heightmap will have to be generated procedurally according to some rules (flat, steppe, ... ) while keeping real heightmaps for particular areas, linked together with large procedural portions.
But for textures, I'm working on a tool to calculate Longitude/Latitude and obtain texture, to make a grid of naturally real blended textures.
Make a networking game entirely as a crew member in a B17, that would be nice
or is this some kind of weird joke?