X window fades and loses color for SDL program in development.

What is the output of:

lsb_release -a; uname -a

Thanks

root@ast2:/home# lsb_release -a
No LSB modules are available.
Distributor ID: Ubuntu
Description: Ubuntu 14.04.2 LTS
Release: 14.04
Codename: trusty
root@ast2:/home# uname -a
Linux ast2 3.13.0-55-generic #94-Ubuntu SMP Thu Jun 18 00:28:41 UTC 2015 i686 i686 i686 GNU/Linux

Also, I am pretty sure that Ubuntu (window manager) is responsible, and not SDL, because the title bar at the top of the window fades also. It happens more like 4 or 5 seconds after the window appears. I am guessing that the window manager concludes mistakenly that my SDL windows are inactive for some reason.

The program I am testing is on github, if someone else wants to try it on their computer. It is project "michael9422/lensy", program name "spectrograph".

If you try a non composting session like XFCE (sudo apt-get install xfce4) then logoff and log back in to the XFCE session, is it OK?

My knowledge about window management is that a program's window is temporarily greyed if the program does not answer (for a certain period). Are you sure that you are not running into some kind of endless loop in your program? What is the status of that program (running, waiting for io...) when that happens?

Yes, I believe that is what is happening. (I will try XFCE too soon, as actionparsnip suggested). All that the program does so far is to calculate the next image and then redraw it using the SDL2 library. The redrawing continues after fading to gray scale. The windows are not interactive (yet). I do not know what the window manager wants from the program to indicate that it is alive, or what functions in SDL2 would provide that.

It does *not* fade to gray using XFCE.
So, that means it is something specific to the default Ubuntu 14.04
window manager (Unity?).

It does *not* fade to gray using XFCE.
So, that means it is something specific to the Ubuntu 14.04 default window manager (Unity?).

Compiz is the WM. Unity is a plugin for Unity.

Sounds like an issue with Compiz, or that the extra load put on the system due to Compiz is causing some issue.

Agreed. Although, I doubt that it is a excessive CPU load issue, because I tested a loop which repeatedly draws graphics and then sleeps for one second, modifying the graphics each time, and it still fades.

I would like to be able to make a change to the program so it would not do that, but how? Is there a special place for compiz help?

OK. I found the answer by googling "compiz SDL fade". I had to call the SDL2 function SDL_PumpEvents.
Thanks.