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glutEnterGameMode(3GLUT)	     GLUT	      glutEnterGameMode(3GLUT)

       glutEnterGameMode,  glutLeaveGameMode  -	 enters	and leaves GLUT's game

       void glutEnterGameMode(void);
       void glutLeaveGameMode(void);

       glutEnterGameMode is designed  to  enable  high-performance  fullscreen
       GLUT rendering, possibly	at a different screen display format.  Calling
       glutEnterGameMode creates a special fullscreen GLUT  window  (with  its
       own  callbacks  and  OpenGL rendering context state).  If the game mode
       string describes	a possible screen display format,  GLUT	 also  changes
       the screen display format to the	one described by the game mode string.
       glutLeaveGameMode leaves	the GLUT game mode and returns the screen dis-
       play format to its default format.

       When game mode is entered, certain GLUT functionality is	disable	to fa-
       cilitate	high-performance fullscreen rendering.	GLUT pop-up menus  are
       not available while in game mode.  Other	created	windows	and subwindows
       are not displayed in GLUT game mode.  Game  mode	 will  also  hide  all
       other  applications  running on the computer's display screen.  The in-
       tent of these restrictions is to	eliminate window clipping issues, per-
       mit  screen display format changes, and permit fullscreen rendering op-
       timization such as page flipping	for fullscreen buffer swaps.

       After leaving game mode,	the GLUT functionality disabled	in  game  mode
       is  available  again.   The  game mode window (and its OpenGL rendering
       state) is destroyed when	leaving	game mode.  Any	windows	and subwindows
       created	before	entering the game mode are displayed in	their previous
       locations.  The OpenGL state of normal GLUT windows and	subwindows  is
       not disturbed by	entering and/or	leaving	game mode.

       The  following GLUT routines are	ignored	in game	mode:  glutFullScreen,
       glutSetWindowTitle,   glutSetIconTitle,	 glutPositionWindow,   glutRe-
       shapeWindow,  glutPopWindow,  glutPushWindow,  glutIconifyWindow, glut-
       ShowWindow, glutHideWindow.

       glutEnterGameMode can be	called when already in game mode.   This  will
       destroy	the  previous game mode	window (including any OpenGL rendering
       state) and create a new game mode window	with a	new  OpenGL  rendering
       context.	 Also if glutEnterGameMode is called when already in game mode
       and if the game mode string has changed and describes a possible	screen
       display	format,	the new	screen display format takes effect.  A reshape
       callback	is generated if	the game mode window changes  size  due	 to  a
       screen display format change.

       Re-entering game	mode provides a	mechanism for changing the screen dis-
       play format while already in game mode.	Note though that the game mode
       window's	 OpenGL	 state	is lost	in this	process	and the	application is
       responsible for re-initializing the  newly  created  game  mode	window
       OpenGL state when re-entering game mode.

       Game mode cannot	be entered while pop-up	menus are in use.

       Note  that  the	glutEnterGameMode  and glutFullScreen routines operate
       differently.  glutFullScreen simply makes the current window match  the
       size  of	the screen.  glutFullScreen does not change the	screen display
       format and does not disable any GLUT features  such  as	pop-up	menus;
       glutFullScreen  continues to operate in a "windowed" mode of operation.
       glutEnterGameMode creates a new	window	style,	possibly  changes  the
       screen  display mode, limits GLUT functionality,	and hides other	appli-

       glutGameModeGet,	glutGameModeString, glutInitDisplayString

       Mark J. Kilgard (

GLUT				      3.7	      glutEnterGameMode(3GLUT)


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