Re: [Flightgear-devel] Expected behavior on "reinit"

[James T. <zak...@ma...>]

On 10 Dec 2014, at 10:59, Anton Gomez Alvedro <gal...@gm...> wrote:

> I have two Nasal modules that try to behave properly on reinit, but I am actually unsure that I am implementing the right behavior.
> 
> (see http://forum.flightgear.org/viewtopic.php?f=30&t=24699&start=15#p226529
> and http://forum.flightgear.org/viewtopic.php?f=66&t=21855&start=90#p226527)
> 
> Could someone please summarize what does /sim/signals/reinit represent (is it only teleporting, a request to start from scratch for every system, other), and how should Nasal scripts behave on such events?
> 
> I also read a while ago that the plan was to drop the Nasal context entirely on reinit, so I wonder if Nasal scripts should take these signals into account or not.

A ‘reset’ now restarts Nasal (and every other subsystem) entirely - this is what happens when changing aircraft or or choosing ‘reset’ from the File menu. (And some other actions can also trigger it).

The old ‘reset’, which does *not* restart Nasal, is now stripped down to the bare minimum of systems needed for repositioning (tele-porting). Since many aircraft Nasal scripts rely on /sim/signals/reinit to do work on being teleported, that behaviour was also retained. 

In an ideal world, there would be a better API to inform aircraft and Nasal modules about a teleport, but for the meantime, the property you mentioned is the one. Eg, really we should have an API to distinguish on-ground vs in-air starts, and adjust the initial state of properties accordingly.

BTW, for the new reset process, the subsystem, including Nasal, is actually destroyed and re-created. This is intentionally to make it almost certain the behaviour after a reset is the same as after the first launch of the sim.

Kind regards,
James