GL_SPOT_CUTOFF not working properly

Question

I'm new to OpenGL. I'm studying OpenGL 2.1 and I'm trying to make a little program to test the GL_SPOT_CUTOFF property, but when I set a value between 0.0-90.0, the light doesn't work and everything is dark.

The code:

void lightInit(void) {

    GLfloat light0Position[] = {0.0,0.0,2.0,1.0};
    glEnable(GL_LIGHTING);
    glEnable(GL_LIGHT0);
    glLightf(GL_LIGHT0, GL_SPOT_CUTOFF, 45.0);
    glLightfv(GL_LIGHT0, GL_POSITION, light0Position);
}

void reshapeFunc(int w, int h) {

    glViewport(0, 0, (GLsizei) w, (GLsizei) h);

    glMatrixMode(GL_PROJECTION);
    glLoadIdentity();

    if (w <= h)
        glOrtho(-4, 4, -4*(GLfloat)h/(GLfloat)w, 4*(GLfloat)h/(GLfloat)w, -4.0, 4.0);
    else
        glOrtho(-4*(GLfloat)w/(GLfloat)h,4*(GLfloat)w/(GLfloat)h, -4, 4, -4, 4.0);

    glMatrixMode(GL_MODELVIEW);
    glLoadIdentity();

    gluLookAt(0,0,0,0,0,-1,0,1,0);

}

void displayFunc(void) {

    glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);

    // center sphere
    glutSolidSphere(1, 100,100);

    // right sphere
    glPushMatrix();
        glTranslatef(3,0,0);
        glutSolidSphere(1, 100,100);
    glPopMatrix();

    // left sphere
    glPushMatrix();
        glTranslatef(-3,0,0);
        glutSolidSphere(1, 100,100);
    glPopMatrix();

    glutSwapBuffers();

}

void keyboardFunc(unsigned char key, int x, int y) {

    if (key==27) {
        exit(EXIT_SUCCESS);
    }

}

int main(int argc, char** argv) {

    //freeglut init and windows creation
    glutInit(&argc, argv);
    glutInitDisplayMode(GLUT_DOUBLE | GLUT_RGB | GLUT_DEPTH);
    glutInitWindowSize(600, 500);
    glutInitWindowPosition(300, 100);
    glutCreateWindow("OpenGL");

    //glew init and errors check
    GLenum err = glewInit();
    if (GLEW_OK != err) {
      fprintf(stderr, "Error: %s\n", glewGetErrorString(err));
      return 1;
    }
    fprintf(stdout, "---GLEW %s---\n\n", glewGetString(GLEW_VERSION));

    //general settings
    glClearColor(0.0, 0.0, 0.0, 0.0);
    glShadeModel(GL_SMOOTH);
    glEnable(GL_DEPTH_TEST);

    //light settings
    lightInit();

    //callback functions
    glutDisplayFunc(displayFunc);
    glutReshapeFunc(reshapeFunc);
    glutKeyboardFunc(keyboardFunc);

    glutMainLoop();

    return 0;

}

This code produces this image:

If I delete glLightf(GL_LIGHT0, GL_SPOT_CUTOFF, 45.0);, the next image is produced:

Is there some kind of bug ?

Answer 1

Code works for me, exactly as presented in the question (after adding the missing #include lines). (Ubuntu 14.10, AMD Radeon HD 5870, running the latest Catalyst drivers)

Middle sphere is hit by the spotlight, left and right spheres are not.

Whatever your problem is, it's presumably not the code (although I haven't tested this on any devices other than the one mentioned above. Possible that there's an "undefined behaviour" bug which happens to work nicely under my driver but which isn't working so nicely under yours).