glutTabletButtonFunc  - sets the special keyboard callback
for the current window.

glutTabletButtonFunc
	glutTabletButtonFunc(func) -> None

void glutTabletButtonFunc(void (*func)(int button, int state,
                          int x, int y));

func      The new tablet button callback function.

glutTabletButtonFunc sets the tablet button  callback  for
the  current window. The tablet button callback for a win-
dow is called when the window has tablet input focus (nor-
mally,  when the mouse is in the window) and the user gen-
erates tablet button presses. The button parameter will be
the  button number (starting at one). The number of avail-
able  tablet  buttons  can  be  determined  with   glutDe-
viceGet(GLUT_NUM_TABLET_BUTTONS).   The  state  is  either
GLUT_UP or GLUT_DOWN indicating whether the  callback  was
due  to a release or press respectively. The x and y call-
back parameters indicate the window  relative  coordinates
when the tablet button state changed.

Registering  a tablet button callback when a tablet device
is not available is ineffectual and not an error. In  this
case, no tablet button callbacks will be generated.

Passing  NULL to glutTabletButtonFunc disables the genera-
tion of tablet button callbacks. When a new window is cre-
ated, no tablet button callback is initially registered.

glutTabletMotionFunc,    glutDeviceGet,    glutMotionFunc,
glutSpaceballMotionFunc

Mark J. Kilgard (mjk@nvidia.com)