There are essentially two ways to get at the new polygon code: via the apt.dat system or via an overlay DSF. When should you use apt.dat and when should you use an overlay DSF?
- If you are trying to model something that is directly in the apt.dat spec, use an apt.dat file. For example, use apt.dat if you are making blue taxiway lights.
- Use a custom overlay DSF if you are modeling outside an airport. (Do not make "fake" airports to use apt.dat features.)
- If you need a custom look not supported by apt.dat, use an overlay DSF - it's the only way.
- Use a custom overlay DSF if you are modeling something that isn't found in an airport, even if it looks similar. (For example, if you want blue lights to model some unique architecture in an airport, do not use apt.dat taxiway lights - your lights may look the same, but they are not the same!)
There are essentially two kinds of features in the scenery system:
- Features that do not change how they look, ever. For example, we do not change the way a textured triangle looks in an OBJ file.
- Features that are designed to model the real world. Over time, we change them to look more like the real world. For example, approach lights have changed a lot in 850 to look more like the real world ones.
(This division of all scenery features between ones that are "stable" and ones that are "based on the real world" can also be seen in most parts of the sim. In particular, the flight model is designed with a "based on the real world" philosophy, a very controversial decision I'll have to blog about some other time.)
Next: fixing airport terrain with polygons.