Emesary is a simple and efficient class based interobject communcation system to allow decoupled disparate parts of a system to function together without knowing about each. It allows decoupling and removal of dependencies by using notifications to cause actions or to query values.
Emesary is all about decoupling and removing dependecies, and improving the structure of code. Using Emesary you can more easily define the what rather than the how. By using what is essential an event driven system it is easy to add or remove modules, and also for extra modules to be inserted that the rest of the aircraft knows nothing about (e.g. FGCamera or the Walker).
see: http://chateau-logic.com/content/emesary-nasal-implementation-flightgear
The AN/SPN-46 is an ACLS implementation using Emesary. ACLS is the Navy's version of ILS.
Seems to be a bad commit b528caf6edb34d9df1015b47b598ec09de4774a6 in old fgdata
"Reduce Z-fighting with light pole light volume by extending it below the ground"
introduces a solid, non-transparent light volume.
