Path: utzoo!utgpu!watmath!clyde!att!whuts!homxb!antique!cjp
From: cjp@antique.UUCP (Charles Poirier)
Newsgroups: comp.sys.amiga
Subject: Re: BOBS?
Summary: BOB subsets please?
Message-ID: <2448@antique.UUCP>
Date: 6 Dec 88 23:13:30 GMT
References: <3603@crash.cts.com> <737@ardent.UUCP>
Reply-To: vax135!cjp (Charles Poirier)
Organization: AT&T Bell Labs, Holmdel, NJ
Lines: 33

In article <737@ardent.UUCP> rap@ardent.UUCP writes:
>In article <3603@crash.cts.com>, billium@pro-charlotte.cts.com (Bill Blanke) writes:
>
>> (3) How do you use the DoubleBuffer structure. It would seem very easy
>> to enact, since its so small, and by programming BOBs, I've figured out...
>>
>Double buffering bobs entails drawing rendering into one buffer while the
>other buffer is being displayed.  By properly initializing the Double Buffering
>structure, you provide a place for the system to save the background that
>one bob is covering up in one buffer, while the Save Buffer (forgot exact
>terminology here) stores the background area for what you're drawing over
>in the current drawing buffer.  Again I must suggest the RKM for what I
>believe is a fairly good description.  (RJ and I wrote it).

The part that tells you how to set up the double-buffered BOBs is
fine.  What I found missing is a description, at that point in the RKM,
on how to double buffer the containing Intuition window.  As it now
reads, it's not clear (to the novice anyway) how to set up the window's
second BitMap (or is it the RastPort?), nor that such is even needed.

Now for my pet beef.  I can't find a documented way to tell the BOBs
system to redraw only a subset of the BOBs.  I have an application
where I am moving one BOB at a time, and I know that only say three out
of fifty or so BOBs are affected, and I also know which three.  If it
has to redraw all fifty, it becomes unacceptably slow.  Do I have to
write up my own replacement for the BOB system to accomplish this, or
is it possible to hack around this problem?  Any help would be appreciated.

	Thanks,
-- 
	Charles Poirier   (decvax,ucbvax,mcnc,attmail)!vax135!cjp

   "Docking complete...       Docking complete...       Docking complete..."