(Error trying to run qjackctl) libEGL warning: DRI2: failed to authenticate qt5ct: using qt5ct plugin

Question

Running Raspbian installed with NOOBS. qjackctl is installed with all its dependencies using Synaptic. Just trying to run Guitarix on my Pi3 B+. I tried following the instructions in this solution, but the ../configure... command at the end just returned an error about missing directories. Help is appreciated, this is my first time using a Pi or Linux.

Answer 1

According to https://www.raspberrypi.org/forums/viewtopic.php?p=971944 and from my own coding experience (I code for a macOs/Windows/Linux project that makes use of the Qt Libs) the RPi's OpenGLES is the embedded form which is not the same as a full Desktop system OpenGL - and some OpenGL stuff does not work on it (sadly that includes the oldest simplest direct OpenGL 1.0 stuff that is exactly what the project I code for uses).

I tried to build this on my RPi and after cloning the Guitarix project (from my ~/src/ directory): git clone http://git.code.sf.net/p/guitarix/git ./guitarix and after changing to the ~/src/guitarix/trunk/ directory and failing to run the command: ./waf --configure through to successful completion, I needed to work my way through finding and installing needed things - though you should be able to do all the package installation steps (with other associated pacakages) at one swell foop:

• create a symbolic link from gcc/g++ to gcc-6/g++-6: sudo ln -s -i /usr/bin/gcc-6 /usr/bin/gcc and sudo ln -s -i /usr/bin/g++-6 /usr/bin/g++
• install intltool and gettext-devel packages: sudo apt-get install intltool gettext-devel
• install sndfile containing package: sudo apt-get install libsndfile-dev
• install gthread containing package: sudo apt-get install libglib2.0-dev
• install glibmm-2.4 containing package: sudo apt-get install libgmm-2.4
• install header fftw3.f containing package: sudo apt-get install libfftw3-dev
• install libcurl containing package: sudo apt-get install libcurl4-gnutls-dev {note this virtual package could also be provided by: libcurl4-openssl-dev or libcurl4-nss-dev but since I already had libcurl3 I suspected the later version (and its development headers) would be the most straightforward to use}
• install jack >= 1.9.2 containing package: sudo apt get install libjack-jackd2-dev {note this installs the jack 1.9.10 version currently}
• install gkt+-2.0 >= 2.20 containing package: libgtk2.0-dev libpango1.0-dev libcairo2-dev

Unfortunately I hit a - hopefully temporary - blockage in that the RPi is currently using libcairo2 and libcairo-gobject2 at version 1.14.8-1+rpi (i.e. an Raspberry Pi special compilation of those two - the unmodified versions are also available as 1.14.8-1) however libcairo2 is only listed as a version 1.14.8-1 and it only accepts the other libcairo packages without the suffix. I have found this Raspberry Pi forum article about it: "Unable to install libgtk2.0-dev on Raspberry Pi 2" and I have reported my findings and my suspicions that we need a libcairo2-dev version 1.14.8-1+rpi with a dependency on the other suffixed packages.

~That is all I can find out at the moment - I hope I can update this when this issue is sorted...~

Update: Seems that in the past I experimented with a different repository and have got some problems to sort out in that- given that I am away from home (and my RPi) for a few days I cannot do anything until I get back.