Re: [Flightgear-devel] JSBSim and airports

[<js...@ha...>]

> js...@ha... writes:
> So, to say the fdm is re-init'd superflously, is not entirely true,
> but it appears that JSBSim is not robust to being reinited with
> changed values.  That's not meant as a knock on the JSBSim code.  It
> just means that not all the pieces are playing happily together.

Yikes! Well, perhaps this is true.

> Thoughts:
> 
> 2. Perhaps what we need to do is change the interface so you have:
> 
> An init() routine that is only called once with the FDM is
> instantiated.

This sounds good to me offhand...

> A re-init() routine that is called when we want the FDM to reset to
> some initial condition (i.e. stationary on the ground at a new
> location.)

Same for this one...

> 4. Perhaps JSBSim should be designed so that you can:
> 
>    a) instantiate it (already done)
>    b) define up some initial state (position, velocity, orientation,
>       trimmmed/not trimmed) (I think mostly already done)
>    c) reset to this new initial state. (This needs to be worked on?)

This sounds good. I wonder if it is already this way, though?

> 5. I see that by my reading of the code there is some odd
> confusion/confounding going on.
> 
> The specific FDM interface init() routine calls the generic
> FGInterface::init() routine.  The FGInterface::init() calls the set_*
> routines would could trigger iterations of the flight model.  This
> happens though before the FDM interface init() is allowed to finish
> it's initializing.  I could see where that could cause problems.

and perhaps some wierd recursive problems?

> I think you are right in saying this is a mess ...
> 
> Jon, Tony, I encourage you to step through the program logic
> carefully, I managed to do it right now.  It didn't give me warm
> fuzzies.  I think we should take a closer look at what's going on here
> and see if we can straighten things out a bit so they make more sense.

OK.

How about delaying the new release for a couple days?

Jon