Question

I have attempted to start programming with OpenGl using this tutorial, and have the following code so far:

#include <gl/glut.h> // Include the GLUT header file

void display (void)
{
}

int main(int argc, char **argv)
{
    glutInit(&argc, argv); // Initialize GLUT
    // Set up a basic display buffer (only single buffered for now)
    glutInitDisplayMode (GLUT_SINGLE);
    glutInitWindowSize (500, 500); // Set the width and height of the window
    glutInitWindowPosition (100, 100); // Set the position of the window
    // Set the title for the window
    glutCreateWindow("Your first OpenGL Window!");

    glutDisplayFunc(display);
    glutMainLoop();
    glClearColor(1.f, 0.f, 0.f, 1.f); // Clear the background of our window to red

    return 0;
}

I build and run the project in Eclipse, it compiles all fine, but nothing happens (no windows pop up or anything). Can anybody tell me what I could be doing wrong?

Answer 1

glutInitDisplayMode (GLUT_SINGLE);

You also need to define the kind of framebuffer format you want, i.e. add a GLUT_RGBA, at least (and you probably also want a depth buffer). And there are only few cases where one not wants a double buffer. So: glutInitDisplayMode(GLUT_RGBA | GLUT_DEPTH | GLUT_DOUBLE);

Then your display function will not be called, unless you add a glutDisplayFunc(display); after glutCreateWindow.

glutMainLoop();
glClearColor(1.f, 0.f, 0.f, 1.f);

glutMainLoop does not return. And even if it did, glClearColor had no effect at that place in the program.