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glutEnterGameMode(3GLUT)             GLUT             glutEnterGameMode(3GLUT)


NAME

       glutEnterGameMode, glutLeaveGameMode - enters and leaves GLUT's game
       mode.


SYNTAX


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


DESCRIPTION

       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
       display format to its default format.

       When game mode is entered, certain GLUT functionality is disable to
       facilitate 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 intent of these restrictions is to eliminate window clipping
       issues, permit screen display format changes, and permit fullscreen
       rendering optimization 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,
       glutReshapeWindow, glutPopWindow, glutPushWindow, glutIconifyWindow,
       glutShowWindow, 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
       display 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
       applications.


SEE ALSO

       glutGameModeGet, glutGameModeString, glutInitDisplayString


AUTHOR

       Mark J. Kilgard (mjk@nvidia.com)

GLUT                                  3.7             glutEnterGameMode(3GLUT)

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