Window Structure Structure window contains the following: GLuint ID window ID number as returned by the windowing system. See GLUT function glutCreateWindow. GLuint displaymode bit mask for display and depth buffer configuration. See GLUT function glutInitDisplayMode. GLuint xpos horizontal origin of viewport GLuint ypos vertical origin of viewport See GLUT function glutInitWindowPosition. GLuint width width of viewport GLuint height height of viewport See GLUT function glutInitWindowSize.