FGFS Status Reports

Updated February 11, 2000

Current Development Summary

Here are some notable landmark items in the development of the Flight Gear project.

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: http://www.hal-pc.org/~jsb/flightsim.html
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.
Terrain: 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 terrain."
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 http://www.terragear.org or http://terragear.sourceforge.net.
HUD: We have a fairly decent configurable HUD implimented with a sample configuration.
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.
Sky: 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.
Autopilot: 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.
Weather: 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.

Supported Platforms

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 fulling supported:

Linux/FreeBSD: 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.
Win32: 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.
Irix: Of course. Flight Gear and it's terrain is pretty amazing on a high end graphics workstation.
Solaris: This is an example of how easy it is to port Flight Gear to just about any Unix that has OpenGL and GLUT support.
Macintosh: 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.
BeOS??? 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.

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.

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

Autopilot

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.

Binary Datafiles

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.

Cockpits

2D Cockpits Friedemann Reinhard has begun work on a stand alone instrument panel library. An early version of this can be found in FlightGear.

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: http://www.menet.umn.edu/~curt/fgfs/msmith/

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.

Engine/Thrust Modeling

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 Peden).

GUI

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.

HUD

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".

Scenery

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.

Weather

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 flightgear yet.

(adaptations by Durk Talsma)

Curtis L. Olson