Undefined symbols for architecture x86_64:"_glutInit", referenced from:_main in main.o / Netbeans on Mac

Question

I´m a beginner with OpenGL and "my" first program is this Sierpinski Gasket. I´m using Netbeans on my MacBook Pro and I believe I have the libraries installed but maybe they are not linked correctly.

#include <iostream>
#include <stdio.h>
#include <OpenGL/gl.h>
#include <OpenGL/glu.h>
#include <GLUT/glut.h>
#include <OpenGL/glext.h>

void myinit(){
    glClearColor(1.0,1.0,1.0,1.0);
    glColor3f(1.0,0.0,0.0);
    glMatrixMode(GL_PROJECTION);
    glLoadIdentity();
    gluOrtho2D(0.0,50.0,0.0,50.0);
    glMatrixMode(GL_MODELVIEW);
}

void display(){
    GLfloat vertices[3][2]={{0.0,0.0},{25.0,50.0},{50.0,0.0}};
    int i, j, k;
    int rand();
    GLfloat p[2]={7.5,5.0};
    glClear(GL_COLOR_BUFFER_BIT);
    glBegin(GL_POINTS);

    for(k=0; k<5000; k++){
        j=rand()*3;
        p[0]=(p[0]+vertices[j][0])/2.0;
        p[1]=(p[1]+vertices[j][1])/2.0;
        glVertex2fv(p);
    }

    glEnd();
    glFlush();
}


int main(int argc, char** argv) {
    glutInit(&argc,argv);
    glutInitDisplayMode(GLUT_SINGLE | GLUT_RGB);
    glutInitWindowSize(500,500);
    glutInitWindowPosition(0,0);
    glutCreateWindow("Sierpinski Gasket");
    glutDisplayFunc(display);
    myinit();
    glutMainLoop();
}

---

Here are the compilation errors:

Undefined symbols for architecture x86_64:

"_glutInit", referenced from:

 _main in main.o

"_glutInitDisplayMode", referenced from:

 _main in main.o

"_glutInitWindowSize", referenced from:

 _main in main.o

"_glutInitWindowPosition", referenced from:

 _main in main.o

"_glutCreateWindow", referenced from:

 _main in main.o

"_glutDisplayFunc", referenced from:

 _main in main.o

"_glutMainLoop", referenced from:

 _main in main.o

ld: symbol(s) not found for architecture x86_64

collect2: ld returned 1 exit status

make[2]: * [dist/Debug/GNU-MacOSX/sierpinski] Error 1

make[1]: * [.build-conf] Error 2

make: * [.build-impl] Error 2

Answer 1

You need to link the GLUT framework. In Project Properties > Linker > Command Line > Aditional Options, specify

-framework GLUT

Answer 2

Slight correction in your code:

j = rand() % 3;

and not rand() * 3;. That gives seg fault for obvious reasons.