How can I configure QT source code if it can't detect default installed OpenGl ES?

[UltraBurstXD]

@SGaist,
libgl-dev, freeglut3-dev, mesa-common-dev and another related. Ubuntu build-essential package too...

[SGaist]

Did you restart the build from a clean state after you installed the development packages ?

[UltraBurstXD]

How do I do that? I'm new in C++, I came from Java. The "clean state" thing... But did some tests, openGL works well for me in the terminal...

[SGaist]

Use an out of source build and nuke it if something goes wrong.

By the way, why are you trying to build from sources ? You can either use the version provided with your distribution or the pre-built version provided by the Qt Company.

[UltraBurstXD]

The one provided by my distro is outdated, very outdated. I downloaded the "offline installer" because there are times I'm without internet.

[SGaist]

The offline installer already provides you with a pre-built Qt.

[UltraBurstXD]

How do I activate it? In tutorial they where explaining how to build from source only... From what I remember. I kinda read the readme file... And the instruction in readme file is:

./configure -prefix $PWD/qtbase <license> -nomake tests
    make -j 4

[SGaist]

Did you actually ran the offline installer ?

[UltraBurstXD]

There is no runnable binary, for what I can see. Or I don't know the name... There are many modules here.

[jsulm]

@UltraBurstXD The offline installer is just one file. But offline installers are not available anymore for open source users (without commercial license). So, what exactly did you download?

[UltraBurstXD]

I downloaded here: https://www.qt.io/offline-installers

[jsulm]

@UltraBurstXD As I said: offline installer is just one file. Make it executable (chmod u+x OFFLINE_INSTALLER_FILE) and execute it. No need to build anything.

[UltraBurstXD]

@jsulm I don't know name of offline installer... It's my first time using qt... perhaps should I specify qt modules path to qt creator? And configure the environment variables?

[jsulm]

@UltraBurstXD Lets do one step after another: you downloaded the offline installer, is that correct? Like http://download.qt.io/official_releases/qt/5.12/5.12.10/qt-opensource-linux-x64-5.12.10.run

[UltraBurstXD]

Yes, I did and extracted the files to home. As seen:

The archive name is qt-everywhere-src-5.15.2.tar.xz

[jsulm]

@UltraBurstXD You did NOT download the offline installer, you downloaded the source code. Can you please post the exact file name you downloaded?

[UltraBurstXD]

It turns out I downloaded Qt 5.15.x Source Packages... My internet data plan... And it can't configure because of OpenGL.

[jsulm]

@UltraBurstXD Didn't you want to install Qt using offline installer as @SGaist suggested? So, what do you want to do now? It is much much easier to install prebuild Qt than to build it by yourself. I suggest you use offline or (better) online installer to install prebuild Qt.

[SGaist]

Then lets go from scratch:

cd /somewhere_NOT_in_Qt_source
mkdir build_Qt
cd build_Qt
/path_to_Qt_sources/configure -nomake tests -nomake examples

What do you get now ?

[UltraBurstXD]

You cannot make a shadow build from a source tree containing a previous build.
Cannot proceed.