> From: Johnathan Van Why <jrvanwhy@gm...> - 2012-08-29 13:20 > > I have a need to run Nasal code at the same rate as the simulation. > > At this point, I am unsure which to pursue. Which method do you find to be > better?
To be frank, the whole idea is just bad in the first place - so I vote for #3: avoid *any* Nasal in the fast simulation loop. Nasal execution is slow and non-deterministic. Running it in the fast simulation loop is the last thing we want. I know, some people on the forum would like to eventually replace fgfs(.exe) with nasal(.exe), because apparently everything is "just better" (tm) when implemented in Nasal (core = bad, nasal = good). But I really think this is a completely wrong direction - and harming the project. Concerning your original issue on implementing an autopilot: a much better way to do it is to avoid Nasal for the actual autopilot controller elements (numeric computation). Instead, use XML "autopilot" rules for the filter, gain, damper, integrator elements: http://wiki.flightgear.org/Autopilot_Configuration_Reference You can then use Nasal for the high level stuff, and enable/disable/switch the individual controller elements (e.g. in order to automatically switch the autopilot mode when capturing the ILS). There are some nice examples with fgdata/Git aircraft. You could look at the 777. This is also how such things are done in the real world: controllers aren't implemented in imperative programming languages these days - especially not in scripting languages. People use model-based design and connect controller elements - using graphical tools like MATLAB/Simulink. Obviously, FG is missing a graphical interface to specify the controller rules - but the idea of specifying through XML is the same and specification is straight forward. cheers, Thorsten ------------------------------------------------------------------------------ Live Security Virtual Conference Exclusive live event will cover all the ways today's security and threat landscape has changed and how IT managers can respond. Discussions will include endpoint security, mobile security and the latest in malware threats. http://www.accelacomm.com/jaw/sfrnl04242012/114/50122263/ _______________________________________________ Flightgear-devel mailing list Flightgear-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/flightgear-devel
