Parameters
cbfun
Pointer to a callback function that will be called every time the mouse is moved. The function
should have the following C language prototype:
void GLFWCALL functionname( int x, int y );
Where functionname is the name of the callback function, and x and y are the mouse coordinates
(see glfwGetMousePos for more information on mouse coordinates).
If cbfun is NULL, any previously selected callback function will be deselected.
Return values
none
Description
The function selects which function to be called upon a mouse motion event.
A window has to be opened for this function to have any effect.
Notes
Mouse motion events are recorded continuously, but only reported when glfwPollEvents,
glfwWaitEvents or glfwSwapBuffers is called.