[SOLVED] Novice, OpenGL, G++ cannot find -lglu

bkelly · 11-16-2018, 01:17 PM

I am using QT Designer from Trolltech version 3.3.8b, the goal is to create a window/panel with an OpenGL display within the QT display. The QT part seems to be fine, it’s the GL part that is a problem.

A tutorial specified to add the two options for lib:

Quote:

-lglut –lglu

G++ says that it cannot find –lglu. It does appear to find –lglut
In path /usr/include/GL there are about 17 files to include glu.h, gl.h, glut.h, and more.

From directory /usr/lib64 issue the command:

Code:

ls –al libGLU.so

to get

Quote:

lrwxrwxrwx 1 root root 15 Oct 25 10:23 libGLU.so -> libGLU.so.1.3.1

That indicates that it exists.
When the -lglu is removed the error is gone but then I must comment out almost everything GL related and the final result from g++ includes this text:

Quote:

DSO missing from command line.

I tried looking at $LIB, $LIBRARY, $LD_LIBRARY_PATH, $LIBPATH, and $SHLIB_PATH but none exist.
I tried the trolltech web site but it is forbidden by the government firewalls and I get a nastygram about how my usage is logged and monitored.
I did try searching this forum for –lglu but found nothing that I could detect as relevant. Where might I look for a solution?

ehartman · 11-16-2018, 02:10 PM

Quote:

Originally Posted by bkelly

I am using QT Designer from Trolltech version 3.3.8b, the goal is to create a window/panel with an OpenGL display within the QT display. The QT part seems to be fine, it’s the GL part that is a problem.

A tutorial specified to add the two options for lib:

G++ says that it cannot find –lglu. It does appear to find –lglut
In path /usr/include/GL there are about 17 files to include glu.h, gl.h, glut.h, and more.

From directory /usr/lib64 issue the command:

Code:

ls –al libGLU.so

You're asking for libglu.* (LOWER case), while the library has its name with UPPER case.
Change the option to -lGLU and it should work.

Background: the -l option asks for a library (mostly in /usr/lib[64]) to be used with the name lib<the string after -l>.a or .so (static or shared library.
So as the library is called libGLU.so the option should be -lGLU

bkelly · 11-16-2018, 02:51 PM

Did that, and in the meantime had tried some other things. Simplifying:
Since -lglu needed to be -LGLU then I wonder why -lglut seemed to work. I say seemed to work because I am not there yet.
Also changed -lglut to LGLUT such that both are in all caps, and it compiles. However, I had commented out all the GL stuff. When glClear(...) is enabled g++ declares:

Quote:

undefined reference to 'glClear'

All the GL calls are commented out except that one. Any reference to GL calls results in an undefined complaint. There appears to be something obvious I have wrong. It did work with just QT stuff and displayed the dialog that has been configured.

After working this all day I have learnt that, in the Libs section of QT Designer is needed:

-lglut -lGL

The first in lower case, the second in uppcase.