// FIXME
void drawBresenhamSphere(int x, int y, int r) {
    for (int i = 0; i < 360; ++i) {
            glPushMatrix();
            {
                glPushMatrix();
                {
                    glRotatef(i, 0, 1, 0);
                    drawBresenhamCircle(x, y, r);
                }
                glPopMatrix();
                glRotatef(90, 1, 0, 0);
                glPushMatrix();
                {
                    glRotatef(i, 0, 1, 0);
                    drawBresenhamCircle(x, y, r);
                }
                glPopMatrix();
            }
            glPopMatrix();
        }
}