title: How to pass non static member function into glutDisplayFunc
body: <p>I have a class which has functionality to initialise opengl and run it in separate thread.</p>
  
  <p>My problem is: openGL callbacks such as glutDisplayFunc, glutMotionFunc etc accepts 
  void (*f) void, and I cannot pass class member function.</p>
  
  <p>ways around.
  1) I can declare member function as static, but in this case I need to declare all used member variables as static, and end up declaring a whole class as a static. </p>
  
  <p>2) I can use some stand alone function and declare my object as global, but its too bad.</p>
  
  <p>I wonder if there are some ways around so I dont need to make my opengl class static ?? (using c++)</p>