Path: utzoo!mnetor!uunet!husc6!uwvax!oddjob!ncar!gatech!bloom-beacon!oberon!pollux.usc.edu!papa
From: papa@pollux.usc.edu (Marco Papa)
Newsgroups: comp.sys.amiga.tech
Subject: Re: Horizontal scrolling problems
Message-ID: <9003@oberon.USC.EDU>
Date: 10 May 88 07:06:57 GMT
References: <2465@mit-amt.MEDIA.MIT.EDU>
Sender: news@oberon.USC.EDU
Reply-To: papa@pollux.usc.edu (Marco Papa)
Organization: Felsina Software, Los Angeles, CA
Lines: 28

In article <2465@mit-amt.MEDIA.MIT.EDU> dlleigh@media-lab.media.mit.edu.UUCP (Darren L. Leigh) writes:
>I am trying to create a hi-res, interlaced horizontally scrolling
|display for use in my heart monitor project.  I have been having some
|weird problems with wide bitmaps and with the ScrollVPort function.
|
|When the bitmap I am using is 1024 or fewer pixels wide, the display
                               ^^^^^^^^^^^^^
|is fine and I just get some hashing when I call ScrollVPort (I know
|the docs said there would be some hashing, but that much?!?).  When
|the bitmap is 1025 or more pixels wide, I get junk on the screen (even
               ^^^^^^^^^^^^
|after clearing the associated rastport, and without doing any
|scrolling).  The junk seems to scroll OK, but jumps around a lot.  I
|don't seem to be able to draw onto the junk either.
|The bitmap in question is attached to the second rasinfo structure of
|a dual playfield display (many thanks to those who helped me get that
|working), but I get the same problem with single playfield displays.
|Am I doing something wrong?  Is there a bug?  Or am I just going crazy?

According to the RKM manual (page 2-20 of Vol. 1 of the CBM edition) :
"The big picture (called a raster and represented by the BitMap structure)
can have a maximum size of 1024 by 1024. "

-- Marco Papa 'Doc'
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