glutButtonBoxFunc  -  sets  the  dial  & button box button
callback for the current window.

glutButtonBoxFunc
	glutButtonBoxFunc(func) -> None

void glutButtonBoxFunc(void (*func)(int button, int state));

func      The new button box callback function.

glutButtonBoxFunc sets the dial & button box button  call-
back  for the current window. The dial & button box button
callback for a window is called when the window has dial &
button box input focus (normally, when the mouse is in the
window) and the user generates dial &  button  box  button
presses.  The  button  parameter will be the button number
(starting at one). The number of available dial  &  button
box    buttons    can    be    determined   with   glutDe-
viceGet(GLUT_NUM_BUTTON_BOX_BUTTONS). The state is  either
GLUT_UP  or  GLUT_DOWN indicating whether the callback was
due to a release or press respectively.

Registering a dial & button box  button  callback  when  a
dial  &  button box device is not available is ineffectual
and not an error. In this case, no dial & button box  but-
ton callbacks will be generated.

Passing  NULL to glutButtonBoxFunc disables the generation
of dial & button box button callbacks. When a  new  window
is  created,  no dial & button box button callback is ini-
tially registered.

glutDialsFunc,   glutDeviceGet,   glutSpaceballButtonFunc,
glutTabletButtonFunc

Mark J. Kilgard (mjk@nvidia.com)