2.1 glutInit

  glutInit is used to initialize the GLUT library.

Usage

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

argcp

A pointer to the program's unmodified argc variable 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, glutInit 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 failure 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 specific 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 specified, the value of the DISPLAY environment variable is used.

-geometry W x H + X + Y

Determines where window's should be created on the screen. The parameter following -geometry should be formatted as a standard X geometry specification. The effect of using this option is to change the GLUT initial size and initial position the same as if glutInitWindowSize or glutInitWindowPosition were called directly.

-iconic

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

-indirect

Force the use of indirect OpenGL rendering contexts.

-direct

Force the use of direct OpenGL rendering contexts (not all GLX implementations support direct rendering 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 fallback 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.