Hi, On Thursday, April 14, 2011 06:07:18 cas...@mminternet.com wrote: > Agree with the first part about hacking, but disagree with the second idea > of "cost" > > HLA is a follow-on to DIS and SimNet developed by DARPA and would require > either an extensive rewrite of FG to be HLA (Stanag 4603) > compliant or a wrapper function, In addition, there is a thing called > Run-Time Infrastructure (RTI) that handles the federates interfaces [...] > Maybe something along the lines of an "HLA-lite". From Durk's suggestion, > and the excerpt above it sounds like the multiplayer server might function > in the manner of an RTI for a limited set of object model types ( unless > we want to include submarines, tanks, bad guys, etc, etc... ;-) )
What you cited above is something that an RTI should implement in the end to be maximum scalable. But, you can implement an rti with just fewer of these options working. Much more than the above, the spatial indices implemented in the rti regions will be a huge benefit, since you will only recieve the messages that are relevant near the region of your interrest. Also the way an rti provides time management and time stamped messages, is benefitial. This enables hard syncronized hla federates, exchanging data at relatively high rates with the least possible communication latency. Regarding the ongoing threading discussion and the amount of cores an avarage cpu has today, an rti will provide a way to implement components of the simulation in a single threaded way, living in its own process. This can be done while still having a deterministic and tight coupling with other federates simulating in the same federation. This kind of coupling is required for example for a good simulation of glider towing for example. > However, a quick search indicates there is an open source HLA on > sourceforge License is Apache License V2.0, no idea how that compare to > GPL or LGPL, but might be worth a look-see. Whatever, it is going to take > time and effort (cost) to make FG compliant amd/or turn the multi-player > server into an RTI clone or "play-alike". And perhaps it would add a bit > of formalism to the FG development track. :-) There is also one, at http://developer.berlios.de/projects/openrti/ Which is subject to envolve. But appart from that, the API is standardized by an IEEE standard and used with commertial simulation systems as well. Simgear also already has some rti abstraction library that should help to implement hla federates. Flightgear git already has an alternative multiplayer implementation in place that uses hla. But that is only thought as a proof of concept. The next step is probably to provide a seperate hla federate that runs the ai traffic and feeds that into an rti federation. All I did here started using the above hla implementation. So this one already works for this kind of stuff. So, there is already something in place, and I think that its definitely worth keeping that in mind. Greetings Mathias ------------------------------------------------------------------------------ Benefiting from Server Virtualization: Beyond Initial Workload Consolidation -- Increasing the use of server virtualization is a top priority.Virtualization can reduce costs, simplify management, and improve application availability and disaster protection. Learn more about boosting the value of server virtualization. http://p.sf.net/sfu/vmware-sfdev2dev _______________________________________________ Flightgear-devel mailing list Flightgear-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/flightgear-devel
