[Flightgear-devel] PLIB features in plib svn but not in any release

[Florent R. <f.r...@fr...>]

Hi,

At [1], I had a discussion with Flughund (== "Alex D-HUND", I suppose?)
that could well use your input. The thing is that Franz Melchior
committed improvements to PLIB widgets in January 2009:

  https://www.mail-archive.com/fli...@li.../msg20793.html

but these improvements never made it into a PLIB release (so far). Franz
was somewhat optimistic and made FG use the features if the PLIB version
is strictly later than 1.8.5 (latest version published):

src/GUI/FGPUIDialog.cxx:#if PLIB_VERSION > 185
src/GUI/FGPUIDialog.cxx:#if PLIB_VERSION > 185

(argh, ugly version number encoding that wouldn't work with 1.8.10 and
later...)

The PLIB original author, Steve Baker, wrote in 2011:

,----[ https://sourceforge.net/p/plib/mailman/message/28580157/ ]
| PLIB is no longer being maintained - it would take too much work to bring
| it up to the latest OpenGL standards.
|
| I don't plan any more releases.  I recommend that FlightGear pulls their
| current version into their repository and make it a part of FlightGear
| itself.
`----

We didn't do that AFAIK, at least not completely, and no one seems to be
wanting to take maintainership for PLIB. For download_and_compile.sh
though (at least I presume this is the reason), FG developer Clément de
l'Hamaide set up this repository:

  https://sourceforge.net/projects/libplib/

which has the exact same code as current PLIB svn (I verified this)
plus a working CMake setup, plus the two security patches mentioned a
few days ago here.

Now, what can we do at a reasonable cost to conveniently enable the
features implemented by Franz Melchior for FG users? The wiki page:

  http://wiki.flightgear.org/Building_FlightGear_-_Devuan#plib

suggested so far to run:

  sed s/PLIB_TINY_VERSION\ \ 5/PLIB_TINY_VERSION\ \ 6/ -i src/util/ul.h

before building PLIB. It's okay but a bit of a hack, and not very
user-friendly. :)

FlugHund on the wiki discussion page[1] proposed to set the PLIB version
to 1.8.6 in the repository maintained by Clément, so that users of this
repository benefit from Franz's latest improvements without having to
fiddle with the PLIB version number. Since I haven't seen anyone taking
the responsibility of a plib-ng/plib 2 [whatever the name] project, I
feel slightly uncomfortable asking Clément to do so, without being
strongly opposed either (and I don't know if Clément would like to apply
that).

I proposed a slightly different way, which is to add some:

  #define PLIB_FLIGHTGEAR_VARIANT 1

to https://sourceforge.net/p/libplib/code/ci/master/tree/src/util/ul.h
and change the FG checks from:

  #if PLIB_VERSION > 185

to something like:

  #if (PLIB_VERSION > 185 || \
       PLIB_VERSION == 185 && PLIB_FLIGHTGEAR_VARIANT >= 1)

This would avoid confusing people, I hope, with an unofficial plib 1.8.6
release. The additional info could of course be added there too:

  src/Main/options.cxx:    cout << "PLIB version: " << PLIB_VERSION << endl;

What do you think?

Regards

[1] http://wiki.flightgear.org/Talk:Building_FlightGear_-_Devuan

-- 
Florent