Okay, I see - thanks for providing a little more information.
I think you might want to start a wiki article to introduce your idea there, and maybe add your findings to it over time, i.e. to document your whole journey there.
The point being that these projects tend to take time, and it is usually considered unfriendly to newcomers to "search the forum" or "search the mailing list". Whereas telling people to look at the wiki for additional pointers/ideas or code snippets/patches does seem to work surprisingly well.
As a matter of fact, I would suggest to see for yourself, if you'd rather be told to "use the forum search" or look at the wiki, so that you can make up your own mind whether it's worth the hassle or not.
Speaking in general, you are right that there are already many existing components in place for this, but depending on what exactly you have in mind, they may be lacking integration for the time being, or may not even be particularly compatible at the moment.
Personally, I have found the wiki to work exceptionally well - even if it's just to be used as a "dump space" to juggle different ideas while evaluating the current situation. I've seen a number of people and efforts that ended up using the wiki to do a "brainstorming", and even when/if things would ultimately stall (or just fail), such "brainstormings" can still be tremendously useful to people wanting to do similar things some time in the future (possibly months or even years after someone has moved onto other projects).
As far as I can tell, how to proceed from here on depends highly on a number of concrete questions, such as:
- if you'd like this to be specific to FlightGear or possibly other flight simulators ?
- if you would like to "control" more than a single fgfs instance ?
- if fgfs is intended to be only used for visualization purposes ?
- if you don't mind not using fgfs at all (as in using virtual traffic that may not be driven by an actual flight dynamics engine)
- if you would like to be able to run the front-end without running flightgear (think, a headless traffic server)
- if you need update rates higher than 1-2 hz
- if you want your traffic to be able to use navigation fixes (VORs, DME, waypoints etc)
- if you want your traffic to use flight plans
Admittedly, these questions may seem a bit overwhelming at first - but actually you won't have to look at many of the pointers provided above, simply because depending on the approach used, there are some implicit/inherent restrictions here, i.e. certain approaches are not compatible with certain answers.
Depending on your background, these may be no-brainers (that is, if you are able and willing to patch/rebuild source code), or that may prove to be very real showstoppers.
You are using the terms "traffic injection", and that's actually another good search term for the forum - you will find many topics discussing the pros & cons of the various approaches.
There is a quote-based summary of the limitations of the built-in AI system available here:
http://wiki.flightgear.org/Status_of_AI_in_FlightGearThis was originally considered controversial by many contributors, and others suggested a better integrated system:
http://wiki.flightgear.org/An_Integrate ... fic_SystemTo provide another high-level overview covering some of the issues of the built-in "AI traffic system", you can refer to the following wiki article, which sums up issues identified by the core developer who came up with the original AI Traffic System, and who's meanwhile also arrived at the conclusion that it would need to be re-done:
http://wiki.flightgear.org/FGTrafficFor anything involving scripted AI objects, you can look at this:
http://wiki.flightgear.org/Scripted_AI_ObjectsBut again, it doesn't make that much sense to really look at all of these pointers without narrowing down your goals/priorities, sharing your background, roadmap/time frame you have in mind - simply because many of these pointers will not make much sense to pursue depending on your ratio of hard/soft goals - so that pursuing a certain approach may sooner or later turn out to be a dead-end, simply because you were not aware of certain issues (showstoppers).
If anything, these pointers are only helpful to provide a little surrounding context to make you aware of what's possible and what isn't. But other than that, I would suggest not to spend that much time digging through all of these unless you seem to have found something that is doing almost exactly what you have in mind. Even then, it may still save you tons of time to ask more specific questions here.
Like you said, many of the things you have in mind, have already been done by people around here - so there is no need to re-invent the wheel.