Troubleshooting graphics artifacts

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The ATI shrinked viewport issue
Texture compression sometimes generates such artifacts
example of ATI driver texture corruption
Example of ATI driver texture corruption

Troubleshooting graphics artifacts will help you are having graphics issues, but a reasonable performance. These include:

  • corrupted textures, colors or pictures;
  • unreadable menus;
  • seeing terrain tiles through the cockpit panel;
  • black panel instruments;
  • ...

An alternative, more generic but synthetic version of this page is available at this forum post

If your problem is that FlightGear runs slowly, better looking first at Troubleshooting performance issues. However, if that doesn't solve your problems, come back here, as here we tell you also how to ask for support.

Known issues

Shrinked view with light blue background

If you have your view port reduced to the bottom left corner, and the rest of the window is blue, you probably have an ATI card that needs a specific workaround, available since v2.10 of FlightGear. For most cards that need it, it is enabled automatically, but some are still not known, So please use the Help > About dialog to report the needed information on your graphics card. Meanwhile, you can solve the problem by manually enabling the hack: use

--prop:/sim/ati-viewport-hack=1

from command line or set it as a property in FGRun, or add the following line to the <sim></sim> section of your $FG_ROOT/preferences.xml:

<ati-viewport-hack>true</ati-viewport-hack>

Black/unreadable panel instruments

If you have this problem but the world and other models (buildings, AI planes...) look ok, it is very possible that you enabled Rembrandt and the aircraft you're using does not support it yet. You can renounce to Rembrandt, or the aircraft, or contact the aircraft developer and report the issue, but first better posting a screenshot and asking on the forum if anybody else has the same issue with that aircraft.

Corrupt textures on ATI cards

The free ATI drivers are subject of intensive improvement, but can still be problematic (see the pictures). Try disabling 'Use Point Sprites for Runway Lights'. (remember to close from the menu to save the setting). If the menu is unreadable, you can disable that feature in the config files $FG_HOME/autosave.xml and/or $FG_ROOT/preferences.xml:

<point-sprites type="bool">false</point-sprites>

Other issues and solutions

If everything's black, or there are other artifacts, you might lack support for texture compression. You can disable it from FGRun, in last page Advanced > Rendering, uncheck Texture compression. However, this is going to be painful for cards with little video memory, especially the integrated cards (see Problematic Video Cards).

Also, another reason for such problems could be that you're using open drivers and dds textures. These use a proprietary compression algorithm, and will cause you problems. Either you decompress them before, or renounce to them (or move to the dark side of proprietary drivers).

What shoud I try?

Graphics artifacts are often due to unsupported OpenGL features, and that lack of support comes from either the graphics card or the drivers. If the issues are very severe, you should really check that you can actually run any OpenGL program. See Graphics drivers configuration for information on how to check if your drivers and which card are being used by FlightGear, other programs to be used for testing and, of course, how to install the drivers.

If however you can run FlightGear but it looks bad, still it could be a driver support problem (and so you should check them), but possibly your hardware doesn't support certain shaders or other rendering effects. If that's the case, try to disable them all, and reenable them step by step, to see if a particular shader is not supported and causes the artifacts. Note that Atmospheric light scattering is a shader!

If these didn't work, it's possibly a bug or a particular configuration that was not tested (you can help with that by testing future releases!). You'll need to ask support to check if it's a real bug, and possibly report the bug on the bug tracker.

Requesting support

To help us help you, please answer the following questions and post your answers on the forum. The more you can answer, the better!

  • Have you recently modified your system (software/OS/hardware)?
  • What graphics card (GPU) and drivers are you using?
  • Is the problem specific to FlightGear? Does it happen with other OpenGL software (fgviewer, glxgears, UrbanTerror...)?
  • What version of FlightGear are you using (please only report bugs after checking the latest release first!)? Have you ever used other versions?
  • How is your frame rate and frame latency (spacing)?
  • How about other osgviewer-based software such as fgviewer?
  • If this happens with other OpenGL software (simulators/games): What graphics drivers are you using, and have you considered updating or downgrading drivers?
  • Did you modify any of the startup settings, or is this with the FG defaults (try the defaults first!)?
  • Are there any messages shown in the console? Have you tried raising the log level?
  • What is your shader detail level? Does anything change when reducing/disabling features in the rendering settings dialogs?
  • Do all rendering artifacts go away once you disable textures (wireframe mode)?

And please also post a screenshot of the rendering settings dialog, and another one showing the problem.