FGFS Status Reports
Updated February 11, 2000
Current Development Summary
Here are some notable landmark items in the development of the Flight
- Flight Model:
Jon Berndt and Tony Peden continue to work on a complete rewrite of
the flight model code in C++. Current efforts involve writing a full
blown flight control system. Tony is developing a C172 model for use
within JSBsim and Jon continues to tweak his X15. You can find out
more information on this corner of the project here:
The LaRCsim flight model code continues to be the default while JSBsim
is being developed. Tony Peden has modified the navion flight model
to pretty accurately represent a c172. The c172 is now the default,
but you can still select the venerable old Navion at compile time.
Work is progressing well on an advanced DEM based terrain/scenery
management system. Tiles are irregularly meshed to significantly
reduce polygon count while maintaining the same detail level, and
eliminating many artifacts of "regular" meshes. The current scenery
includes detailed coastlines, urban areas, and land use data.
Although these "advanced features are mainly found in areas covering
the USA, we are looking into finding date for these features for the
rest of the world too. In addition, a binary file format and database
is being considered that will more effectively store the current
The terrain/scenery work is considered sufficiently important that we
have begun to spin this off as it's own project. We have named this
spin off project "TerraGear". You can find more information about the
TerraGear project and read it's mission statement at
We have a fairly decent configurable HUD implimented with a sample
- 2D Instrument Panels:
This is an area where we have not made a lot of progress. We have a
start of an implimentation, but it relies on OpenGL behavior that
isn't gauranteed to be consistant between all cards.
Recently David Megginson has submitted a replacement for this first
attempt that is "OpenGL complient." The graphics are not as flashy,
but it is more simply coded and more functional. Look for this to
show up soon.
- Astronomical Objects:
We have stars, planets, the Sun, and the Moon. All of these are
placed correctly in the sky for the current time and view
position. The moon has the correct phase. The sun smoothly changes
color and becomes much more orange/red as it aproaches the
horizon. The stars and the planets have the correct magnitudes
(brightness.) Find your favorite constellation in the right spot in
the sky for your location, date, and time. Also, we have realistic day
-> dusk -> night -> dawn -> day lighting transitions and stars are
phased in and out in stages so you don't have the light switch effect
where suddenly all the stars appear in the sky in their full glory.
The sky smoothly blends into haze at the horizon. We have implemented
a smoothly blended redish/orange color When the sun is low in the
horizon (sunset/sunrise.) The sky color and blending is tied to the
sun position so the the transitions between full daylight through
sunset to night is incredibly smooth and realistic.
Look for the sky and many of the astronomical objects to be
reimplemented in ssg sometime in the future.
- Sun and Lighting/Shading:
Correct sun positioning. This is an important feature because we can
tie lighting and shading effects to the current sun position. This
means the correct side of the mountains and valleys will be lit. As
the day progresses from sunrise to sunset (if you are patient) you can
observe the shadows moving from one side to the other. This also
allows us to draw the moon with the correct phase by just illuminating
the moon sphere from the correct sun direction.
The current autopilot has the following features: Heading hold,
Altitude hold, height above terrain hold, and auto throttle. In
addition, a great-circle navigation utility is available that will
allow the autopilot to fly and optimal great circle route to any
airport in the database.
Christian Mayer is working on a system to maintain a live weather
database in a form suitable for extracting local conditions and
interpolating between nearest weather stations. Also, code to read
and parse METAR reports and store the herein contained weather
information has recently been added to FlightGear. Currently no visual
weather effects (other than static clouds) exist, however. Work on
weather visuals is in Progress.
- Aircraft Visuals and External views:
As of version 0.7.0, FlightGear uses plib, written by Steve Baker, for
terrain rendering. A major advantage of this switch is that it will
allow us cool things like external views, or 3D cockpits with relative
ease. Although not much work has been done on 3D cockpits yet, some
experimental code exists that gives us an external view.
Recent versions of plib include a 3ds format file loader so we should
have a large library of objects at our disposal.
One of the goals of FlightGear is to be portable and support as many
platforms as possible. To achieve this goal, Flight Gear is written in
ANSI C/C++, on top of OpenGL and GLUT. In addition, we use plib to
provide support for many other things that typically cause portability
problems such as the joystick, the gui, and sound. This provides a
pretty good amount of portability. The following platforms are
As long as you have a C/C++ compiler, OpenGL, and GLUT you have a
pretty good shot of porting Flight Gear to your platform. If you have
a favorite platform not listed here, feel free to contact us. We would
be more than happy to provide porting assistance and work in support
for new platforms into the core source code tree.
Free versions of Unix make great, powerful, flexible, inexpensive
development platforms. The promise of XFree86 4.0 and DRI means that
these unix will soon have equal or better performance than windows on
the same hardware.
Yeah, we know, but lots of otherwise nice people run it. :-) We have a
working build based on the EGCS overlay to the Cygnus Win32 gcc
compiler. Accelerated OpenGL drivers are supported under Windows.
Of course. Flight Gear and it's terrain is pretty amazing on a high
end graphics workstation.
This is an example of how easy it is to port Flight Gear to just about
any Unix that has OpenGL and GLUT support.
Darrell Walisser (and others before him) have made great progress with
the mac port. There are certain parts that haven't been ported yet,
but minus these few things, running Mac versions have been rumored to exist.
We've heard rumblings about people interested in this platform, but so
far no one has come forward with a port. We are hopeful though, and
are eager to answer questions and help however we can.
Summary by Project
Audio As part of "plib" of TUX_AQFH fame, Steve Baker has been
putting together a basic audio library that can play a sound sample,
loop continuous sound samples, and mix any combination of these. You
can set the volume and pitch of the sounds individually and on the
fly. "Plib" is available at: http://www.woodsoup.org/projs/plib
Jeff Goeke-Smith wrote a basic "heading hold". More recently, the
functionality of the autopilot was extended by Curtis Olson to include
a altitude hold, height above terrain hold, and an auto-throttle.
Norman Vine has written an extension to the heading hold system that
will allow great-circle navigation to a destination airport. He is
also working on a system that will enable/disable the autopilot in a
way that is similar to real airplanes.
Gary van Sickle is working on a binary datafile format for FlightGear
that will allow us to store the scenery tiles more efficiently, and
load them quicker.
2D Cockpits Friedemann Reinhard has begun work on a stand alone
instrument panel library. An early version of this can be found in
3D Cockpits: It looks like Michael Smith can generate 3d
cockpit models in a format that will be usable from within Flight
Gear. It will take some effort to generate the models and incorporate
these into the simulator, but the end results should be slick. You can
check out some of Michael's modeling work at:
Note, there are pluses and minuses to both the 2D and 3D cockpit
approach. Ideally, Flight Gear will support both as best as possible
on today's hardware so the user can toggle between one or the other
and the HUD in whatever ways make sense.
A person from Austrialia who I can't remember their name at the moment
has begun work on an accurate model of the performance and behavior of
a piston engine. If you know who you are, please remind me so I can
insert your name here and not sound like a total fool. :-)
Flight Dynamics Modelling A replacement Flight Dynamics model
is being written by John Berndt that will allow the modelling of a
wide range of different aircraft types. In addition we still have the
Navion modelled in Larcsim, and a C172 replacement (written by Tony
Durk Talsma is working on incorporating Steve Baker's PUI library into
FG so that we can have a runtime point and click interface. Durk has sumitted
the first version of this which basically sets up the menu structure. You
can show/hide the menu by pressing the "F10" key. Functionality has been
added to the menu by Norman Vine. Note that a lot of the proposed menu
items are not yet implemented.
Charlie Hotchkiss and Michelle America began work on
the heads up display. Charlie has completely re-written the original
hud code in C++. Charlie also has navaids and navigation instrument
modeling in his sights. Norman Vine has also contributed
substantially to the appearance and performance of the HUD.
Documentation and Publicity
Michael Basler has written an article on Flight Gear for a German
flight sim magazine. This magazine has agreed to allow us to post the
English translation of this article after July 1, 1998 (??-DT) when
the magazine is mailed out to it's subscribers. Michael has also -in
close cooperation with Bernhard Buckel- written the "Installation and
getting started" document, which is an invaluable document for
FlightGear "rookies" as well as "Veterans".
Curt has been continuing to plow away at scenery and scenery rendering
issues. Thanks to his efforts we currently have a large scenery
database, consisting of large areas of the world. Currently the USA
scenery contists of correct terrain elevations, coastlines, some land
use data such as glaciers and marshes, urban areas, lakes and
rivers. The rest of the world constists currently mainly of elevations
and coastlines. Currently Curt is focusing on matching the various
data sources that are used to generate the FG world even better and
also resolve some nasty data errors. Curt has also indicated that the
next major thing he plans to work on is adding airport runways,
lighting, and other objects to FlightGear.
Time managment / Timezones
Durk Talsma has adapted code from glibc that allows FlightGear to
approximate in which timezone it is currently flying. The current
implementation allows the specification of a given start-up time. The
current version is considered early beta and will require some
cleaning. Durk has also indicated that he wants to attempt to refine
the code for the sun/moon position that is currently still to be found
in the Time subdir. Eventually this should be moved to Astro.
Christian Mayer and Mark Vallevandt, with assistance from Durk
Talsma, have written a weather database system that is capable of
reading and storing, and interpreting METAR reports. Although
currently not used, this database system will eventually pass
atmospherical conditions to the Flight Model and the aircraft
instruments on the one hand, and be used to generate visual weather
effects on the other. Some experimental code exsists that models
the visual effects of Rain, thunderstorms (lightning!!), 2 and 3D
clouds. We also have a Rainbow! None of this code has been added to
(adaptations by Durk Talsma)