Aircraft Center

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This article describes content/features that may not yet be available in the latest stable version of FlightGear (2020.3).
You may need to install some extra components, use the latest development (Git) version or even rebuild FlightGear from source, possibly from a custom topic branch using special build settings: .

This feature is scheduled for FlightGear 4.2. 50}% completed

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Canvas dialog showing the prototype for an Aircraft Center for directly installing/managing aircraft from within FlightGear, an upcoming feature scheduled for FlightGear 3.2, currently being developed by TheTom and Zakalawe

Background

Cquote1.png The "built-in" GUI/launcher is one of the longest-standing feature requests - but it's not just about the GUI (which is rather straightforward in comparison), but about the simulator never having been developed with this requirement, i.e. run-time reinitialization, in mind - thus, things like "fgrun" (and a plethora of other external launchers) were developed, which acted as a front-end on top of FG, so that FG itself wouldn't need to be changed - i.e. kind of a "remote control" using command line arguments. So it's there for a reason - fgrun uses the FLTK GUI library, which while relatively simple, is much more powerful than our legacy GUI engine, PUI.


Still, people have been asking for this for years, and it's thanks to pretty much a single person, Zakalawe, that switching aircraft is going to become possible pretty soon - he handled all the ugly work of cleaning up the simulator internals to make this happen - it's not exactly glamorous work, you gotta touch a ton of places, and you inevitably introduce a ton of regressions along the way.


— Hooray (Thu Jun 26). Re: About FlightGear being user-friendly or not.
(powered by Instant-Cquotes)
Cquote2.png
Cquote1.png And yes, even the legacy FG GUI is entirely based on XML and configurable through just editiing XML files - but the collection of "widgets" (GUI controls like buttons, checkboxes, labels etc) is extremely small and very inflexible.


This is something that is currently being addressed by TheTom and Zakalawe, who've both been working on a new Canvas GUI, and a new Canvas GUI dialog called "Aircraft Center", which -while still experimental- is intended to eventually allow end-users to easily download/install aircraft right within the simulator, and also switch between aircraft at run-time without having to exit/restart the simulator.

Thus, adopting Canvas is going to address a number of long-standing issues, but it's obviously a process that only just got started, and it will not happen overnight - 2-3 release cycles are not far-fetched, that's how long the whole migration could very well take, unless there are more people interested in helping.


— Hooray (Thu Jun 26). Re: About FlightGear being user-friendly or not.
(powered by Instant-Cquotes)
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Status

Cquote1.png I made some experiments with creating a GUI using Canvas, but it’s not an area I especially enjoy or feel comfortable working in, so progress was slow, and recently, non-existant.
Cquote2.png
Cquote1.png 've pushed now a first version of an aircraft install/removal dialog.

Was a lot more effort than expected, but now there are a lot of
improvements available useful for every type of dialog.


— Thomas Geymayer (2014-06-10). Re: [Flightgear-devel] select/download aircraft.
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Cquote1.png The dialog is available in the menu (File > Aircraft Center) and shows

a list of the 100 first aircrafts available to install/remove. I've
chosen to limit the number, because with showing all aircrafts at once
I got a delay of a few seconds on opening the dialog. I will
investigate into this more later. You can use the according buttons to
install/remove aircrafts - which I have already done successfully.
Currently the dialog does not indicate any progress and needs to be
reopened to update the buttons.

As the feature freeze is already approaching, I won't be able to add
too much features for this release. So I think there won't be any
keyboard input/searching for this release. I want to support different
tabs to show a list of eg. just the installed aircrafts and do a
simple cache for all the downloaded images, to have them visible
faster on opening the dialog.


— Thomas Geymayer (2014-06-10). Re: [Flightgear-devel] select/download aircraft.
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Cquote1.png Thomas Geymayer and I are working on it, I am not sure where’s he go to with the UI, the backend pieces are mostly there but will need some intensive testing. There is a #define flag you can toggle (in HTTPClient.cxx) to enable the code including the Nasal API; it will download / refresh a catalog, which is generated by the scripts I committed to fgmeta a week ago. Then you can access the package system from pkg.root in the Nasal console, using the API defined at the bottom of HTTPClient.cxx.


If you are crazy enough to enable this code, and run it, be aware it downloads zips, unpacks them, makes calls to unlink files, renames directories, and so on. I would recommend some caution, and especially, don’t run it as root - while developing it I had it extract a few zips to ‘/‘ or worse due to screwed up path logic.

Equally, I would welcome a code review of the code in simgear/package/Install.cxx to check any security issues or dangerous behaviour. The code /tries/ to be ‘safe’ - extract zip to a temporary folder, and uses rename/unlink to atomically update if the zip extraction succeeds. But it’s only had one pair of eyes on it so far.


— James Turner (2014-06-10). Re: [Flightgear-devel] select/download aircraft.
Cquote2.png

Placeholder

Cquote1.png also suspect that there are some logistical issues to solve for aircraft downloads, since it needs aircraft developers and ‘the project’ to start thinking about hangar structures and adding better metadata to aircraft -set.xml; but no one is going to consider those issues until the GUI interface exists. Of course we can initially make a hangar / catalog from all aircraft in fgdata - we already have some tooling around this anyway, which Curt & Gijs use to create the aircraft pages on flightgear.org.


My June is going to be busy, and contains two weeks when I’ve got reduced connectivity/availability, so if these features are going to make it into 3.2, someone other than me needs to take charge of making them happen - I am happy to document what currently exists, and what remains to be solved, in more detail than above.


Cquote2.png
Cquote1.png Well, if we make a manual catalog.xml from the current fgdata/Aircraft (which I have parts of a script to do), and we treat the current aircraft zip URLs as canonical, that is possible with current code right now - since it can do the zip download + extraction to a directory of our choice. We could throw an (ugly) PUI UI around that, and then if someone with more talent than me wants to Canvas-GUI-ify it, that will be great.


I will attempt to get a prototype version of this working tonight / tomorrow. I don’t promise to produce anything usable but as you say, anything would be an improvement.


— James Turner (2014-05-30). Re: [Flightgear-devel] select/download aircraft.
Cquote2.png
Cquote1.png f you give me something that shows how to do this I can put it in a

canvas dialog and see what is missing. Nearly all required parts for
the GUI are now finished and I think within a few days I should be
able to commit the remaining parts.


— Thomas Geymayer (2014-05-30). Re: [Flightgear-devel] select/download aircraft.
Cquote2.png
Cquote1.png My next objective will be actually switching to an aircraft, and setting up the correct paths so that dependencies work; this is more or less orthogonal, I will make a new command to select an aircraft (and reset the sim) based on an aircraft ID or fully-qualified ID. (Again to allow catalogs with ID collisions, such as org.flightgear.default.747-400 and nl.gijs-hangar.beta.747-400)


If anyone wishes to start adding tags or more meta-data to aircraft in FGdata, please let me know, especially to keep the tag space coherent and hence useful for searching.


— James Turner (2014-06-10). Re: [Flightgear-devel] select/download aircraft.
Cquote2.png
Cquote1.png the whole thing is still pretty experimental, it’s probably not at the ‘this text should be a little to the left’ point. We’re more at the ‘it didn’t erase your C drive? Great!’ stage….
— James Turner (2014-06-13). Re: [Flightgear-devel] Notes on Aircraft Center....
Cquote2.png
Cquote1.png The layout and widget systems is now maturing, so I think after 3.2 I

can start with porting PUI. Just one major component is missing, namely
keyboard input and the according input focus.

I guess this will take one or two more releases.


— Thomas Geymayer (2014-06-13). Re: [Flightgear-devel] Notes on Aircraft Center....
Cquote2.png

Tagging

Cquote1.png Related to this, does anyone know how standardised the <status> values are? If there is a defined list of values I will add query support and expose them as an enum to Nasal.


And, if anyone who has a custom hangar would like to start maintaining a catalog, please let me know - there is no UI in FG to add additional catalogs yet but it would help with testing. If you already have a web server with zip files of aircraft, you only need to serve one extra XML file to run a ‘package-ified’ hangar. The catalog XML can be hand written or generated using any technology you like - there’s Python scripts in fgmeta, but PHP / shell-script / etc will all work too.


— James Turner (2014-06-11). Re: [Flightgear-devel] select/download aircraft.
Cquote2.png
Cquote1.png have updated my script with to restrict tags to the set I original wrote on the wiki some time ago:


http://wiki.flightgear.org/Catalog_metadata

I am going to do make a drive-by assault on fgdata/Aircraft adding tags - hopefully no maintainer feels this is problematic since it’s purely adding metadata to make the UI more functional. I am sure I will get some entries ‘wrong’ and the tags themselves are still up for discussion, but we have a version control system, and most of the tags are very non-controversial.

The ‘nicer’ Nasal tags syntax is added now too. (Part of the motivation for adding tags to fgdata is to test it better(


— James Turner (2014-06-12). Re: [Flightgear-devel] select/download aircraft.
Cquote2.png

Variants

Cquote1.png I don’t think there’s any pathological examples with more than eight -set.xml. Designating the ‘main’ -set.xml is still an issue.


What I will do is include the set-file and description in a ‘variants’ list, with the first entry being the default. So in the catalog XML, something like:

<package>
<variant>
<id>747-400-FO</id>
<name>747-400 First-officer mode</name>
</variant>
...
</package>

On Package I’ll expose this as string_list of variants() with a nameForVariant(std::string variant) helper. For Nasal I can return a dictionary.

Variant IDs will need to be unique within the Catalog, and I’ll update the search logic to accept /any/ variant ID as matching the package - this will make the aircraft-startup part of everything work, and keeps thing close to how it behaves with unpackaged aircraft.


— James Turner (2014-06-13). Re: [Flightgear-devel] select/download aircraft.
Cquote2.png

Development

Cquote1.png I thought about adding a cache add Canvas::Image or rather at the

HTTPRequest level to cache all HTTP requests/files which have not set
a no-cache header.


— Thomas Geymayer (2014-06-10). Re: [Flightgear-devel] select/download aircraft.
Cquote2.png
Cquote1.png for a first step I want to limit it only to the

HTTPMemoryRequest which is mainly used for downloading canvas images. So
it should not affect too many parts.
Someday we should probably add a cache limit - but not now ;-) I will
also need this for displaying tilemaps.


— Thomas Geymayer (2014-06-10). Re: [Flightgear-devel] select/download aircraft.
Cquote2.png
Cquote1.png A semi-related small thing: I'd like to have saved-between-sessions

"default aircraft/starting airport" properties (/sim/default-aircraft,
/sim/default-airport ?), set by a "make this default" check box in Go To
Airport and the new aircraft dialog, so those who prefer something other
than c172p@... don't have to select it on every startup. I should be
able to implement this, but comments would be appreciated.


— Rebecca N. Palmer (2014-05-30). Re: [Flightgear-devel] select/download aircraft.
Cquote2.png
Cquote1.png Currently box layouts are available. Once they fully

work I'll start thinking of other layouts and widgets.


— Thomas Geymayer (2014-06-13). Re: [Flightgear-devel] Notes on Aircraft Center....
Cquote2.png
Cquote1.png I want

to implement a cache to speed it up after the first time, but not for
3.2. If an image fails to load there should be a message in the terminal.
"No thumbnail available" is shown if there is no image specified in the
catalog.


— Thomas Geymayer (2014-06-13). Re: [Flightgear-devel] Notes on Aircraft Center....
Cquote2.png
Cquote1.png what I’d want is tabs at the top for ‘installed aircraft’, ‘available updates’ and so on. But again the question is really what UI we can build in the time available.
— James Turner (2014-06-13). Re: [Flightgear-devel] Notes on Aircraft Center....
Cquote2.png

Known Issues

Cquote1.png Prior to a reset, if you edit /sim/aircraft, it works as you would expect. However there are some quirks related to aircraft-specific menu items / dialogs, at least on Mac (the custom menu for previous aircraft is not removed).


There may be other bugs, since this feature is not used by anyone yet.


— James Turner (2014-05-30). Re: [Flightgear-devel] select/download aircraft.
Cquote2.png
Cquote1.png If you've created a grid control for Canvas, it would be nice to see the

FDM, Systems, Cockpit and Model ratings broken out into individual columns
so you could sort by them. :)

If you get to the point where you can change aircraft from this dialog,
you might want to include a checkbox that will limit the list to installed
aircraft.

If the Aircraft Center dialog is open, other dialogs don't appear to work
- I tried exiting via File->Exit and none of the items were selectable.
Hitting ESC brings up the Exit dialog, but the buttons were not clickable.

Dismissing the Aircraft Center dialog allowed the other dialogs to operate
properly.


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