F03GL: How to use OpenGL extension functions such as glActiveTextureARB and glMultiTexCoord3fARB

[nightcat]

I want to realize the 3D graph in Intel oneAPI Fortran and VS 2023 by using F03GL (Fortran 2003 Interface to OpenGL) mixed programming of Fortran and C/C++ for my application. 

I tried to test thunderbirdgl.f90 and thunderbirdvbo.f90 from bluebook of f03gl_trunk-r76 download from https://code.launchpad.net/~hwkrus/f03gl/trunk, the F03GL library from  https://www-stone.ch.cam.ac.uk/pub/f03gl/index.xhtml includes all objs from the sources codes of OpenGL_gl.f90, OpenGL_glu.f90, OpenGL_glut.f90, OpenGL_freeglut.f90,gltools.f90, math3d.f90 and glut_fonts.c, and opengl32.lib, glut32.lib, glut64.lib (freeglut.lib), glew32.lib, glew32s.lib. However, I always encounter the same type fatal errors of "error LNK2019: unresolved external symbol_ glActiveTextureARB, ..." when I do this like:compile and link command in x64 CMD:

>ifort /Qm64 thunderbirdgl.f90 gltools.obj gltools_c.obj math3d.obj opengl_gl.obj opengl_glu.obj opengl_glut.obj glut_fonts.obj opengl32.lib glut64.lib glew32.lib glew32s.lib

(All these objs and libs are in the same directory as thunderbirdgl.f90 is.)

After exexuting the above command, the 2 messages of error LNK2019 are shown in CMD window, such as:

thunderbirdgl.obj : error LNK2019: unresolved external symbol _ glActiveTextureARB referenced in function _SETUPRC

thunderbirdgl.obj : error LNK2019: unresolved external symbol _glMultiTexCoord3fARB referenced in function _renderscene 

For thunderbirdvbo.f90, there are the same error messages. 

I note that these OpenGL extension functions have been defined in opengl_gl.f90. 

Now I don't know how to solve this problem.  Can any experienced expert or specialist help me about this?

Many thanks in advance!

[willamabroy2]

To use OpenGL extension functions like first load them using an extension loader then call them like regular OpenGL functions.

[andrew_4619]

A strange comment to add to a topic that is two years old, particularly as is a simplistic comment to a subject that had quite extensive discussion.

[Steve_Lionel]

It's usually indicative of someone who is about to spam the forum.

[andrew_4619]

I think you are correct Steve! 

[willamabroy2]

Include the OpenGL extension headers, then get function pointers using a loader like GLEW . Once loaded, call and like normal functions.

[joywalim]

Include the OpenGL extension headers (like glext.h)  load the functions using a loader (e.g. GLEW or glad)  then call them like this

glActiveTextureARB(GL_TEXTURE0_ARB); glMultiTexCoord3fARB(GL_TEXTURE1_ARB, x, y, z);

Make sure your GPU and driver support the extensions.

[qasimdhool]

In F03GL  use use GL and call extension functions like glActiveTextureARB directly if supported. If not  bind them manually using glGetProcAddress.