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, glutSetI-conTitle, glutSetIconTitle,
conTitle, 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 sim-ply simply
ply 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(3G), glutGameModeString(3G), glutInitDisplayString(3G)
AUTHOR
Mark J. Kilgard (mjk@nvidia.com)
GLUT 3.7 glutEnterGameMode(3GLUT)
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