glutEnterGameMode(3GLUT) GLUT glutEnterGameMode(3GLUT)NAME
glutEnterGameMode, glutLeaveGameMode - enters and leaves
GLUT's game mode.
SYNTAX
void glutEnterGameMode(void);
void glutLeaveGameMode(void);
DESCRIPTIONglutEnterGameMode is designed to enable high-performance
fullscreen GLUT rendering, possibly at a different screen
display format. Calling glutEnterGameMode creates a spe
cial 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 render
ing. GLUT pop-up menus are not available while in game
mode. Other created windows and subwindows are not dis
played 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 glu
tEnterGameMode 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
GLUT 3.7 1
glutEnterGameMode(3GLUT) GLUT glutEnterGameMode(3GLUT)
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 rou
tines operate differently. glutFullScreen simply makes
the current window match the size of the screen. glut
FullScreen 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 2
