Canvas issues

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Critical / Bugs

White Square / No FBO

Regarding the Canvas related issues you are mentioning, those would seem to suggest that your GPU/driver is lacking support for features required for Canvas - which is exactly why we're asking people to provide complete bug reports, including their GPU make/model and OS/driver etc (see the red box at the top of the support forum)[1]

The white square is the popup message / tooltip, shown via the Canvas. The texture or framebuffer used for the canvas isn't working. This seems to happen on some very old drivers.[2]

For example, reported on Intel GMA 3100, Intel G33/G31 Express Chipset Family[3]

on an old Intel graphics netbook, and while FG obviously doesn't work very well, some of the osg RTT demos actually DO work correctly. Besides, osgviewer itself, and even fgviewer, work well enough, with acceptable framerates/performance - so it would seem possible to optimie things a bit to also support such hardware.[4]

if in doubt, post more screenshots detailing exactly what you are doing, or even post a youtube video illustrating the problem[5]

please post your hardware specs as per the box at the top of the forum.

It seems that you are lacking some OpenGL support that is required by the new canvas system.

This has been recently reported at least once: viewtopic.php?f=68&t=20887&hilit=canvas+fbo

So please follow up with your exact hardware/software specs, including info from the HELP/ABOUT dialog.

And if you are affected by this, please consider filing a bug report so that we can look into it:[6]

we talked about this issue a (long) while ago - and what would really be interesting is if people seeing this could also try one of the aircraft using other OD_gauge based avionics (navdisplay, agradar, wxradar etc) - because under the hood, this should be using the same OSG code - if those instruments work/display properly, it is likely that this issue can be fixed once and for all by looking at what the Canvas FBO/RTT setup code is doing differently compared to od_gauge based avionics using the same back-end. If I remember correctly, we also once posted patches telling OSG to use a non-FBO fallback - unfortunately nobody seeing this issue was able to follow up to test this. If in doubt, anybody seeing this, PLEASE post a screenshot showing your help/about dialog (and ideally your fgfs.log file): About dialog

Commonly used debugging tools#fgfs.log

About dialog 2.10.png

Likewise, this should affect any other FBO use-cases in FlightGear, including multi-camera setups (think Rembrandt)[7]

could the people getting "white canvases" please get in touch to test a patch ?

Basically, the idea is to check if FBO setup failed and try some more conservative alternatives like pbuffers or ARBs instead.

We can use PIXEL_BUFFER_RTT or PIXEL_BUFFER instead of FRAME_BUFFER_OBJECT: Given that we're going to use Canvas in more and more placed, including the GUI, it would seem like a good idea to get this sorted obviously.

On the other hand, it is hard to troubleshoot this without being affected by the problem yourself :-) it's not a new problem:[8]


  1. Hooray  (Aug 27th, 2014).  Re: Some bugs or errors with the FG 3.2 RC 1 .
  2. zakalawe  (Jan 30th, 2017).  Re: White square error .
  3. Martien van der P.  (Dec 7th, 2015).  Having trouble with changing from to 3.4.0 .
  4. Hooray  (Mar 15th, 2014).  Re: Blank .
  5. Hooray  (Apr 3rd, 2016).  Re: No text in dialog boxes .
  6. Hooray  (Dec 5th, 2013).  Re: Blank .
  7. Hooray  (Feb 25th, 2017).  Re: White square error .
  8. Hooray  (Feb 21st, 2014).  Re: Blank .