[NOT AN ISSUE] Qt 5 on Ubuntu 12.04 with no 3D acceleration



  • Hi,

    I have just converted my project to Qt 5 and I am able to build it on Ubuntu 12.04, but... I can't run it! My Ubuntu 12.04 machine is in fact a virtual machine (under VirtualBox), and I can't enable 3D acceleration on it (either an issue with VirtualBox or my host machine (OS X 10.8.2)). Whatever the case, if I try to run my project, I get the following message:

    bq. Failed to load platform plugin "xcb". Available platforms are:
    Aborted (core dumped)

    So... what am I missing? I initially thought it was an issue with my lack of 3D acceleration, but it can't be since I can run Qt Creator on my Ubuntu 12.04 virtual machine...

    Cheers, Alan.


  • Moderators

    You are missing quite a few libs, probably. Lack of acceleration is not a problem on Linux, as we are blessed by existence of mesa project.

    Please take a look at and install Qt5 dependencies listed "here":http://qt-project.org/wiki/Building_Qt_5_from_Git.



  • Blessing is a little arguable, considering the abysmal performance compared to stock drivers, puts quite a different perspective on the merits of open source. What's the point of getting a 500$ GPU and using drivers that reduce performance to that of a 50$ one...

    Hopefully, the project will pick up the pace in therms of performance.



  • @sierdzio: unless I am mistaken, the Qt 5 dependencies are to build Qt 5 from source which is not what I am trying to do. Still, I noticed something about Libxcb, so I installed the recommended packages for Ubuntu. This being said, it hasn't made any difference. I still can't run my application and I still get the same message that I mentioned above.

    Otherwise, I noticed that Qt 5 is shipped with some "platforms" plugins, one of which is libqxcb.so. So, I thought I would copy those plugins to my application's plugins folder, but again to no avail (I might have done something wrong or missed something else though!).

    So, still stuck...


  • Moderators

    Well yes, good point, I just wanted the post to be a bit more lively than giving only hard facts ;)

    While mesa's performance might not be good, it still puts tux users in a better situation than people on Windows, who have no decent software renderer.


  • Moderators

    [quote author="DocOx" date="1357901121"]@sierdzio: unless I am mistaken, the Qt 5 dependencies are to build Qt 5 from source which is not what I am trying to do. Still, I noticed something about Libxcb, so I installed the recommended packages for Ubuntu. This being said, it hasn't made any difference. I still can't run my application and I still get the same message that I mentioned above.

    Otherwise, I noticed that Qt 5 is shipped with some "platforms" plugins, one of which is libqxcb.so. So, I thought I would copy those plugins to my application's plugins folder, but again to no avail (I might have done something wrong or missed something else though!).

    So, still stuck...[/quote]

    Some of them are needed only for compilation, yes (git, perl, etc.), but others are needed to run Qt (ICU, OpenGL, platform stuff, etc.).

    Platform plugins should be put into "plugins/platforms" directory of your app. It's not needed if you develop with Qt Creator, though, it will provide the app with appropriate environment.



  • Well, I have installed all the possible dependencies and... still no luck. Ok, I guess the next thing for me to try is to get one of Qt 5's example to work on my VM...



  • If it isn't "plugins/platforms" it might be just "platforms" as well (I can't seem to remember this). For testing purposes you can use $QT_QPA_PLATFORM_PLUGIN_PATH or the -platformpluginpath command line argument as well.

    Be aware that even if there is no hardware acceleration support due to VirtualBox beeing moody again you can use a software rasterizer like llvmpipe in order to still get somewhat decent OpenGL support.

    On a sidenote: The reason why there are no competitive open source drivers is the circumstance, that the manufacturers still refuse unwaveringly to release any sort of technical documentation or description, data sheets or any other method to use their hardware properly. The information used to create the current drivers has been made available purerly due to reverse engineering, behavioral analysis and trial and error. So if there is anyone to blame it is for sure not the open source community. There are, however, closed source drivers released by the manufacturers which provide the same performance as on Windows.



  • FWIW, my application should work fine on my Ubuntu 12.04 VM, even without any 3D acceleration. As I mentioned in my original message, Qt Creator works fine and so does a Qt example which I have just built in my VM. So, there has to be something funny with the way I build my application...



  • [quote author="Lukas Geyer" date="1357903535"]If it isn't "plugins/platforms" it might be just "platforms" as well (I can't seem to remember this). For testing purposes you can use $QT_QPA_PLATFORM_PLUGIN_PATH or the -platformpluginpath command line argument as well.[/quote]Did any of this work?



  • [quote author="Lukas Geyer" date="1357911227"][quote author="Lukas Geyer" date="1357903535"]If it isn't "plugins/platforms" it might be just "platforms" as well (I can't seem to remember this). For testing purposes you can use $QT_QPA_PLATFORM_PLUGIN_PATH or the -platformpluginpath command line argument as well.[/quote]Did any of this work?[/quote]

    I tried -platformpluginpath with some path to the platform plugin, and my application was indeed able to pick up some things, but then I got a problem with the SQLite driver not loading (while, again, it used to be all fine before I ported my application to Qt 5).

    Anyway, I don't believe the issue I originally described is valid (since Qt Creator and the Qt example I tried work fine), hence I 'closed' it.



  • Ok, I have 'fixed' my issue. It was a problem with my qt.conf file. I haven't looked into detail, but the one which I used with Qt 4.8 was doing the job, but not with Qt 5.



  • [quote author="DocOx" date="1357910138"]FWIW, my application should work fine on my Ubuntu 12.04 VM, even without any 3D acceleration. As I mentioned in my original message, Qt Creator works fine and so does a Qt example which I have just built in my VM. So, there has to be something funny with the way I build my application...[/quote]

    In Qt5 OpenGL is a dependency for QtGui and is not optional on a per-project basis, even if you don't use OpenGL in your project, the only choice you have to not use OpenGL is to make an entire new build of Qt with OpenGL disabled.



  • Is this issue resolved ?
    Seems that there is a problem with virtualbox & 3D acceleration ?
    I there Any combination which works OK ?



  • @ranshalit I must confess that I can't recall the details of this issue (3 years ago...), but it's certainly working fine now. If it can help, you can look at my project's source code here.


Log in to reply
 

Looks like your connection to Qt Forum was lost, please wait while we try to reconnect.