Using OpenGL glutDisplayFunc within class

Question

I've created a C++ class (myPixmap) to encapsulate the work performed by the OpenGL GLUT toolkit. The display() member function of the class contains most of the code required to set up GLUT.


void myPixmap::display()
{
    // open an OpenGL window if it hasn't already been opened
    if (!openedWindow)
    {
        // command-line arguments to appease glut
        char *argv[] = {"myPixmap"};
        int argc = 1;
        glutInit(&argc, argv);
        glutInitDisplayMode(GLUT_SINGLE | GLUT_RGB);
        glutInitWindowSize(640, 480);
        glutInitWindowPosition(30, 30);
        glutCreateWindow("Experiment");
        glutDisplayFunc(draw);
        glClearColor(0.9f, 0.9f, 0.9f, 0.0);
        glClear(GL_COLOR_BUFFER_BIT);
        glutMainLoop();

        openedWindow = true;
    }  
}

The display function passed to glutDisplayFunc() is another member function of the class:


void myPixmap::draw(void)
{
    glDrawPixels( m,n,GL_RGB,GL_UNSIGNED_BYTE, pixel );
}

However, gcc 4.2.1 on Mac OS X 10.6.4 refuses to compile this code, claiming that:

argument of type 'void (myPixmap::)()' does not match 'void (*)()'

Is there a way to use the GLUT toolkit inside a member function of a class, or must I call all GLUT functions within the main function of the program?

Using OpenGL glutDisplayFunc within class

4 Answers