glutInit

glutInit is the initialization routine for the OpenGL Utility Toolkit (GLUT). It initializes the GLUT library and negotiates with the underlying windowing system to prepare for creating windows, contexts, and events. It is typically the first GLUT routine invoked in a program that uses GLUT.

The function is declared as void glutInit(int *argcp, char **argv). It takes pointers to the program’s argc and argv so that GLUT can modify them, usually by removing GLUT-specific command-line options. Because of this, it is common to call glutInit at the very start of main, before other GLUT functions, and to pass the program’s real argc/argv as arguments.

Command-line options processed by GLUT are implementation-dependent, but GLUT may recognize options related to display selection or window geometry and may strip these options from argv as it processes them. Because different implementations (such as freeglut or platform-specific GLUT variants) may support different options, developers should refer to the specific library’s documentation for exact options and behavior.

Relation to other GLUT calls: glutInit must be called before any other GLUT routines, and its primary role is to initialize the library and the window system. After glutInit, a program typically calls glutInitDisplayMode to specify the framebuffer and buffering options, followed by glutInitWindowSize and glutInitWindowPosition, and finally glutCreateWindow to create the application window. In short, glutInit provides the initial setup that enables subsequent GLUT operations.