Calling gluPerspective and gluLookAt gives me an undefined reference?

Question

I'm trying the following source, from Instant Glew:

#include <GL/glew.h>
#include <GL/freeglut.h>
#include <GL/glu.h>
#include <GL/gl.h>

void initGraphics()
{
    glEnable(GL_LIGHTING);
    glEnable(GL_LIGHT0);
    const float lightPos[4] = {1, .5, 1, 0};
    glLightfv(GL_LIGHT0, GL_POSITION, lightPos);

    glEnable(GL_DEPTH_TEST);
    glClearColor(1.0, 1.0, 1.0, 1.0);
}

void onResize(int w, int h)
{
    glMatrixMode(GL_PROJECTION);
    glLoadIdentity();
    glViewport(0, 0, w, h);
    gluPerspective(40, (float) w / h, 1, 100);
    glMatrixMode(GL_MODELVIEW);
}

void onDisplay()
{
    glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);

    glLoadIdentity();
    gluLookAt(0.0, 0.0, 5.0,
          0.0, 0.0, 1.0,
          0.0, 1.0, 0.0);

    glutSolidTeapot(1);
    glutSwapBuffers();
}

int main(int argc, char** argv)
{
    glutInit(&argc, argv);
    glutInitDisplayMode(GLUT_DEPTH | GLUT_DOUBLE);
    glutInitWindowSize(500, 500);
    glutCreateWindow("Teapot");

    initGraphics();
    glutDisplayFunc(onDisplay);
    glutReshapeFunc(onResize);

    glutMainLoop();
    return 0;
}

My build setup is the Windows 10 VSCode, with MSYS2, and a Makefile like this:

OBJS = 01-teapot.cpp
OBJ_NAME = C:/<"MyProjectPath">/build/01-teapot
INC_PATH = -IC:/msys64/mingw64/include/GL -LC:/msys64/mingw64/include/GL
INC_LINK_LIBS = -lglew32 -lopengl32 -lfreeglut
compiling :
    g++ -Wall $(OBJS) $(INC_PATH) $(INC_LINK_LIBS) -o $(OBJ_NAME) -g

But the output is like:

C:\Users\<"myUser">\AppData\Local\Temp\cc5d3AtP.o: In function `onResize(int, int)':
c:\<"MyProjectPath">\PaPu_Instant_GLEW/01-teapot.cpp:22: undefined reference to `gluPerspective'
C:\Users\<"myUser">\AppData\Local\Temp\cc5d3AtP.o: In function `onDisplay()':
c:\<"MyProjectPath">\PaPu_Instant_GLEW/01-teapot.cpp:31: undefined reference to `gluLookAt'
collect2.exe: error: ld returned 1 exit status
make: *** [Makefile:32: compilando] Error 1

I really don't know where I'm failing. Did I forget to link some lib? I tried to add -lglut -lGLU already, on the linked libs, but the compiler can't find it...

`gluLookAt` is a function from the GL utility library. You need to include `-lglu32`. It's explained in [Using GLUT with MinGW](https://www.transmissionzero.co.uk/computing/using-glut-with-mingw/). — legends2k, Apr 10 '18 at 23:44

legends2k · Accepted Answer · 2018-04-10T23:58:18.993

2

gluLookAt is a function from the GL Utility library. You need to include -lglu32 in the linker options. It's explained in Using GLUT with MinGW.

Also the order in which you give the libraries matter; see my related answer for reference. In your case, replace glfw3 with freeglut.

I believe you are using GLUT and GLU for learning OpenGL which is okay but be informed that they were part of OpenGL 1 back in the day but is no longer an integral part of OpenGL and are deprecated. If you're doing production-level work, I'd recommend using a more mature library like GLFW (instead of GLUT/FreeGLUT); GLM has all the convenience functions that GLU provides. See towards the end of datenwolf's answer.

edited Apr 10 '18 at 23:58

answered Apr 10 '18 at 23:50

legends2k

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I could also get rid of the `glu` and `gl` headers, and it's still working fine ! – Victoralm Apr 10 '18 at 23:56
That's because FreeGLUT includes them for its use perhaps. I'd still be okay to have them explicitly listed to know what functions your cpp references from which headers. Read the advice newly appended to the end of the answer. – legends2k Apr 10 '18 at 23:59
You got the point, I'm indeed learning OpenGL. But I think that I go, for production-level, with the `SDL2` and `glew`. Of course, if isn't any downside on it... I'm just using `freeglut` to follow the book exemples. – Victoralm Apr 11 '18 at 00:03
1

SDL2 is quite mature, so sure, use it. I'd not recommend GLEW however; it has some bugs. Instead use http://glad.dav1d.de/ which most people have moved to. Instead of including a library for extensions, since you know, at compile-time what all extensions you'd use, make it a header and plunk it into your project and reduce dependencies; it's simpler and cleaner. See [here](https://www.khronos.org/opengl/wiki/OpenGL_Loading_Library) for more options. – legends2k Apr 11 '18 at 00:05
Thanks for the advise, I'll start looking for `glad` asap !! – Victoralm Apr 11 '18 at 00:10

Calling gluPerspective and gluLookAt gives me an undefined reference?

1 Answers1