In fact, you
register a display callback via glutDisplayFunc() before you enter glutMainLoop().
For onscreen windows, you should not depend upon the window concretely existing or being visibile until you are told that it exists and is visible via a registered callback.
The return value is an
It should be positive for valid windows or 0 if failure occurred for some reason (Though traditional GLUT tends to bail out and abort rather than returning errors.) The integer is your Bf Li
window id Ef
. Old GLUT promises that these integers are ``small''; we do not reuse old Bf Li
s, but do produce them sequentially.
You can change the title later via glutSetWindowTitle().