glutInit(3GLUT) GLUT glutInit(3GLUT)

NAME
glutInit - initialize the GLUT library.

SYNTAX
void glutInit(int *argcp, char **argv);

ARGUMENTS
argcp A pointer to the program’s unmodified argc vari-
able from main. Upon return, the value pointed
to by argcp will be updated, because glutInit
extracts any command line options intended for
the GLUT library.

argv The program’s unmodified argv variable from
main. Like argcp, the data for argv will be
updated because glutInit extracts any command
line options understood by the GLUT library.

DESCRIPTION
glutInit will initialize the GLUT library and negotiate a
session with the window system. During this process, glu-
tInit may cause the termination of the GLUT program with
an error message to the user if GLUT cannot be properly
initialized. Examples of this situation include the fail-
ure to connect to the window system, the lack of window
system support for OpenGL, and invalid command line
options.

glutInit also processes command line options, but the spe-
cific options parse are window system dependent.

X IMPLEMENTATION NOTES
The X Window System specific options parsed by glutInit
are as follows:

-display DISPLAY
Specify the X server to connect to. If not speci-
fied, the value of the DISPLAY environment vari-
able is used.

-geometry WxH+X+Y
Determines where window’s should be created on the
screen. The parameter following -geometry should
be formatted as a standard X geometry specifica-
tion. The effect of using this option is to
change the GLUT initial size and initial position
the same as if glutInitWindowSize or glutInitWin-
dowPosition were called directly.

-iconic Requests all top-level windows be created in an
iconic state.

-indirect
Force the use of indirect OpenGL rendering con-
texts.

-direct Force the use of direct OpenGL rendering contexts
(not all GLX implementations support direct ren-
dering contexts). A fatal error is generated if
direct rendering is not supported by the OpenGL
implementation.

If neither -indirect or -direct are used to force
a particular behavior, GLUT will attempt to use
direct rendering if possible and otherwise fall-
back to indirect rendering.

-gldebug
After processing callbacks and/or events, check if
there are any OpenGL errors by calling glGetError.
If an error is reported, print out a warning by
looking up the error code with gluErrorString.
Using this option is helpful in detecting OpenGL
run-time errors.

-sync Enable synchronous X protocol transactions. This
option makes it easier to track down potential X
protocol errors.

SEE ALSO
glutCreateWindow, glutInitWindowPosition, glutInitWindow-
Size, glutMainLoop

AUTHOR
Mark J. Kilgard (mjk@sgi.com)

GLUT 3.2 2