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From: sweetmr@SCT60A.SUNYCT.EDU (michael sweet)
Newsgroups: comp.sys.sgi
Subject: Re: clear() bug?
Message-ID: <1405.on.Thu,.11.Apr.91.08:22:40.EDT.@sct60a.sunyct.edu>
Date: 11 Apr 91 12:22:40 GMT
Sender: daemon@ucbvax.BERKELEY.EDU
Organization: The Internet
Lines: 17

Re:  drawing into the background

> How can I solve this problem, i.e., why doesn't clear() work?

Well, clear() works fine, but you are only working on the back buffer when
drawing (by default.)  One thing that I do (with my stars program) is to
have a clear() count- when a REDRAW event comes in, this is set to 2 so both 
buffers get cleared.  Another way would be to enable the clearing on both
windows:

 frontbuffer(TRUE);
 backbuffer(TRUE); /* default */

and then clear().  Be sure to turn the frontbuffer off with frontbuffer(FALSE)
after the clear, tho...

 -Mike