Change the rotation of a 3D sphere to the exact opposite direction with GLUT

I have a program i created with a rotating sphere (glutWireSphere) and i like to change the rotation to the exact opposite direction.

For example if it rotates slowly CW on the Y axis i want it to rotate CCW.

Here is the code i have so far:

float angle = 0.;

    void display() {
    	glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
    	glLoadIdentity();
    	glPushMatrix();
    	glTranslatef(0., -1.5, 0.);
    	glRotatef(angle, 0.5, 1., 0.5);
    	glColor3d(0, 0, 1);
    	glutWireSphere(2, 25, 15);
    	glPopMatrix();
    	glutSwapBuffers();
    	glFlush();
    }
    
    void idle() {
    	angle += 0.2;
    	if (angle > 360.) angle -= 360.;
    	glutPostRedisplay();
    }

    void myinit() {
    	glClearColor(1.0, 1.0, 1.0, 1.0);
    	glMatrixMode(GL_PROJECTION);
    	glLoadIdentity();
    	glOrtho(-6., 6., -6., 6., -6., 6.);
    	glMatrixMode(GL_MODELVIEW);
    }

    void main(int argc, char** argv) {
    	glutInit(&argc, argv);
    	glutInitDisplayMode(GLUT_DOUBLE | GLUT_DEPTH | GLUT_RGB);
    	glutInitWindowSize(400, 400);
    	glutInitWindowPosition(10, 10);
    	glutCreateWindow("3d objects");
    	glutDisplayFunc(display);
    	glutIdleFunc(idle);
    	glEnable(GL_DEPTH_TEST);
    	myinit();
    	glutMainLoop();
    }

To do what i just wrote i changed the values of the X, Y & Z arguments inside the glRotatef function of the display function to -0.5,-1.,-0.5 and i still get the exact same rotation.

I also tried to change the idle function to this (with the original glRotatef arguments):

void idle() {
    	angle -= 0.2;
    	if (angle < 0.) angle += 360.;
    	glutPostRedisplay();
    }

And still, same rotation.

Am i missing something in my understanding here about the glRotatef function?

Hve you tried: glRotatef(-angle, 0.5f, 1.0f, 0.5f);

Yeah, I did…

How can you tell which direction the sphere is rotating? For a wireframe sphere with an orthographic projection and no lighting, the front and back will be indistinguishable. The movement of the vertices at the back will be a mirror image of those at the front, and you can’t tell which is which. So changing the rotation direction will have no visible effect.

If you try it with a solid, texture-mapped sphere with depth tests enabled, you’ll see that you are actually changing the direction of rotation. The difference should also be noticeable with a perspective projection provided that the viewpoint is significantly closer to the front of the sphere than to the back.