Aerospace Blockset™

Introducing the Flight Simulator Interface

About the FlightGear Interface

The Aerospace Blockset™ product supports an interface to the third-party FlightGear flight simulator, an open source software package available through a GNU General Public License (GPL). The FlightGear flight simulator interface included with the blockset is a unidirectional transmission link from the Simulink^® interface to FlightGear using FlightGear's published net_fdm binary data exchange protocol. Data is transmitted via UDP network packets to a running instance of FlightGear. The blockset supports multiple standard binary distributions of FlightGear. See Running FlightGear with the Simulink^® Models following for interface details.

FlightGear is a separate software entity neither created, owned, nor maintained by The MathWorks.

• To report bugs in or request enhancements to the Aerospace Blockset FlightGear interface, use this form http://www.mathworks.com/contact_TS.html.

• To report bugs or request enhancements to FlightGear itself, visit www.flightgear.org and use the contact page.

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Obtaining FlightGear

You can obtain FlightGear from www.flightgear.org in the download area or by ordering CDs from FlightGear. The download area contains extensive documentation for installation and configuration. Because FlightGear is an open source project, source downloads are also available for customization and porting to custom environments.

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Configuring Your Computer for FlightGear

You must have a high performance graphics card with stable drivers to use FlightGear. For more information, see the FlightGear CD distribution or the hardware requirements and documentation areas of the FlightGear Web site, www.flightgear.org.

MathWorks tests of FlightGear's performance and stability indicate significant sensitivity to computer video cards, driver versions, and driver settings. You need OpenGL^® support with hardware acceleration activated. The OpenGL settings are particularly important. Without proper setup, performance can drop from about a 30 frames-per-second (fps) update rate to less than 1 fps.

Graphics Recommendations for Windows

The MathWorks recommends the following for Windows^® users:

• Choose a graphics card with good OpenGL performance.

• Always use the latest tested and stable driver release for your video card. Test the driver thoroughly on a few computers before deploying to others.

  For Microsoft^® Windows XP systems running on x86 (32-bit) or AMD-64/EM64T chip architectures, the graphics card operates in the unprotected kernel space known as Ring Zero. This means that glitches in the driver can cause Windows to lock or crash. Before buying a large number of computers for 3-D applications, test, with your vendor, one or two computers to find a combination of hardware, operating system, drivers, and settings that are stable for your applications.

Setting Up OpenGL^® Graphics on Windows

For complete information on OpenGL settings, refer to the documentation at the OpenGL Web site: www.opengl.org.

Follow these steps to optimize your video card settings. Your driver's panes might look different.

1. Ensure that you have activated the OpenGL hardware acceleration on your video card. On Windows, access this configuration through Start > Settings > Control Panel > Display, which opens the following dialog box. Select the Settings tab.

   

2. Click the Advanced button in the lower right of the dialog box, which brings up the graphics card's custom configuration dialog box, and go to the OpenGL tab. For an ATI Mobility Radeon 9000 video card, the OpenGL pane looks like this:

   

3. For best performance, move the Main Settings slider near the top of the dialog box to the Performance end of the slider.

4. If stability is a problem, try other screen resolutions, other color depths in the Displays pane, and other OpenGL acceleration modes.

Many cards perform much better at 16 bits-per-pixel color depth (also known as 65536 color mode, 16-bit color). For example, on an ATI Mobility Radeon 9000 running a given model, 30 fps are achieved in 16-bit color mode, while 2 fps are achieved in 32-bit color mode.

Setup on Linux^®, Macintosh^®, and Other Platforms

FlightGear distributions are available for Linux^®, Macintosh^®, and other UNIX^® platforms from the FlightGear Web site, www.flightgear.org. Installation on these platforms, like Windows, requires careful configuration of graphics cards and drivers. Consult the documentation and hardware requirements sections at the FlightGear Web site.

Using MATLAB^® Graphics Controls to Configure Your OpenGL^® Settings

You can also control your OpenGL rendering from the MATLAB^® command line with the MATLAB Graphics opengl command. Consult the opengl command reference for more information.

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Installing and Starting FlightGear

The extensive FlightGear documentation guides you through the installation in detail. Consult the documentation section of the FlightGear Web site for complete installation instructions: www.flightgear.org.

Keep the following points in mind:

• Generous central processor speed, system and video RAM, and virtual memory are essential for good flight simulator performance.

  The MathWorks recommends a minimum of 512 megabytes of system RAM and 128 megabytes of video RAM for reasonable performance.

• Be sure to have sufficient disk space for the FlightGear download and installation.

• The MathWorks recommends configuring your computer's graphics card before you install FlightGear. See the preceding section, Configuring Your Computer for FlightGear.

• Shutting down all running applications (including the MATLAB interface) before installing FlightGear is recommended.

• MathWorks tests indicate that the operational stability of FlightGear is especially sensitive during startup. It is best to not move, resize, mouse over, overlap, or cover up the FlightGear window until the initial simulation scene appears after the startup splash screen fades out.

• The current releases of FlightGear are optimized for flight visualization at altitudes below 100,000 feet. FlightGear does work not well or at all with very high altitude and orbital views.

Aerospace Toolbox supports FlightGear on a number of platforms (http://www.mathworks.com/products/aerotb/requirements.html). The following table lists the properties you should be aware of before you start to use FlightGear.

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About Aerospace Coordinate Systems

Working with the Flight Simulator Interface