GL/gl.h and GL library

SGaist

Where is that file located on your system ?

ugstudent

[ugstudent@localhost ~]$ locate GL/gl.h

/home/ugstudent/Desktop/Qt_5.12.3/5.12.3/Src/qtwebengine/src/3rdparty/chromium/third_party/mesa/src/include/GL/gl.h
/home/ugstudent/Desktop/Qt_5.12.3/GL_lib_stuff/mesa-20.1.2/include/GL/gl.h
/home/ugstudent/Documents/mesa-20.1.2/include/GL/gl.h

SGaist

So in fact, you did not install the OpenGL development package on your system, did you ?

ugstudent

I tried to verify OpenGL and got this

[ugstudent@localhost ~]$ glxinfo | grep OpenGL
OpenGL vendor string: VMware, Inc.
OpenGL renderer string: llvmpipe (LLVM 7.0, 128 bits)
OpenGL version string: 2.1 Mesa 18.3.4
OpenGL shading language version string: 1.20
OpenGL extensions:
OpenGL ES profile version string: OpenGL ES 2.0 Mesa 18.3.4
OpenGL ES profile shading language version string: OpenGL ES GLSL ES 1.0.16
OpenGL ES profile extensions:

If this is incorrect, how do I verify or install OpenGL?

jsulm

@ugstudent "OpenGL development package".
Development packages usually have "-dev" package suffix, like somepackage-dev.rpm.
Please check this: https://doc.qt.io/qt-5/linux.html

sudo yum groupinstall "C Development Tools and Libraries"
sudo yum install mesa-libGL-devel

stretchthebits

@ugstudent
OpenGL is installed on all Linuxes. You have version 2.1 and the renderer (the guys you wrote the driver) is Mesa (the Mesa project).
In other words, you can run programs that need OpenGL 2.1 and below.

For programmers:
In your case, you need to install the development package. I know that there are a few header files. gl.h which is the main one. glext.h if you want functions from GL 1.2 and above. glu.h (contains a few functions for rendering a sphere, cylinder and such and is very old).
There is also a few OS specific functions. I think on Linux, it is the glx.h file that has those functions, such as for swapping the back buffer with the front buffer.
There are also the project called the OpenGL wrangler (aka GLEW). This makes it easier to use GL 1.2 and above functions. What the GLEW library does is dynamically fetch addresses to GL functions.

You just need to figure out how to install the GL development package for your CentOS and QTCreator.

ugstudent

I tried the two commands listed.

Running

sudo yum groupinstall "C Development Tools and Libraries"

I get

Warning: group C Development Tools and Libraries does not exist.
Error: No packages in any requested group available to install or update

and running

sudo yum install mesa-libGL-devel

I get

Package mesa-libGL-devel-18.3.4-7.el7_8.1.x86_64 already installed and latest version
Nothing to do

jsulm

@ugstudent Search for gl.h like this:

find /usr -name gl.h

Is it there?

ugstudent

I got it working. Thank you for all your help.

SGaist

Great !

What did you do ?

sozhg

I met this error on Windows, could you please share your experience on how to solve it?