OpenGL libraries linking

Why should we link OpenGL libraries? I am using Visual C++ 6.0, I was told to inlcude OpenGL32.lib GLu32.lib glut32.lib into Project/Settings.

But, my program works fine even without including of those libraries. What happen? What is the different if I were to link the libraries and without linking it?

[zukko]

maybe you are including them using #pragma comment(lib,"opengl32.lib"); or maybe you are not using the opengl functions

I never include #pragma (I don't know what it is as well), and I am using pure OpenGL function, just really confuse.

I program OpenGL using Window Console Application, after I have compiled and build the file, I go to my Project Settings/Link, the libraries shown are:

kernel32.lib user32.lib gdi32.lib winspool.lib comdlg32.lib advapi32.lib shell32.lib ole32.lib oleaut32.lib uuid.lib odbc32.lib odbccp32.lib

As you may see, the program works fine even without including any OpenGL libraries. Or may it be the case where the OpenGL libraries are included once, and need not to be included at the subsequent time?

I just want to know whether you all include those OpenGL libraries 'each time' you create a new project, or incluce it once, and no need to include it again next time when creating a new project? Or OpenGL libraries are not necessary for console application?

[dvm]

Someone correct me if I'm wrong, but the libraries is what ties the executables with your source code. You're calling a library function, any function. The compiler will need the library file so it can find the address of the function in the dll file. My guess is that the compiler you're using knows where to find the .lib's
A couple of years ago when I started learning OpenGL this thing had me fumbled for 4 days, as I used an glaux function and my project could not link to the auxiliary library.
In the end, know that the thing happens, even if it is done automatically, and you don't know about it.
PS At least you know what to do if your compiler start spitting link errors

I agree with you too. If any one who have better solution, just hope that you guys may share it here. I think my question is slightly out of OpenGL topic, however, as we are programming in OpenGL, we need to know some lower-end implementation especially for debugging purpose, right?

Meanwhile, I am looking for this answer too, if I manage to get the answer, and I will share it over here.

[zukko]

on your main() function write glLoadIdentity();
then compile and link, if it does it without any errors please tell me

Is this what you mean:

  void main()
{
	glutInitDisplayMode(GLUT_DOUBLE | GLUT_RGB);
	glutInitWindowSize(400, 400);
	glutCreateWindow("libLinking");
	glutDisplayFunc(RenderScene);
	glutReshapeFunc(Reshape);
 
	glLoadIdentity();
 
	setupRC();
 
	glutMainLoop();
}

If this is the code, then my IDE generate no error on it.

I will not reply by today if I am buzy because I am rushing my OpenGL assignment and for another two hours more, it is the assignment deadline. What make ridiculous is that there is one last part remaining, that is I don't know how to transform a straight line to a curve line upon animation.

I know it is not fair to me ask for help for my assignment, but I just want to know is there any OpenGL API function which can transform straight line to a curve line? glTranslate? glScale?

For library linking issues, I hope that we can discuss further later. Now my time here is 05:14am

[zukko]

1) you are using glut
2) i dont have the least idea why it doesnt have errors
3) for your assignment, use a line strip, then gradualy move on the X or Y axis the vertex points to start generating a curve

[mikael_aronsson]

If you are allowed to use glu functions you could also create a spline/nurbs curve, then you can simply transform the line to a curve by moving the control handles for the curve.

Mikael