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Article View: comp.sys.amiga.tech
Article #2094

Re: Fast/smooth/easy vertical scrolling

#2094
From: Eduardo Horvath
Date: Sun, 12 Nov 1989 20:35
23 lines
1804 bytes
In article <993@mit-amt.MEDIA.MIT.EDU> dlleigh@media-lab.media.mit.edu.UUCP (Darren Leigh) writes:
>I'm looking for various ways to do fast and smooth vertical scrolling
>of text.  Both up and down scrolling are necessary.  Prefereably the
>scrolling should take as little CPU time as possible.  I also need to
>have the sprites usable over the entire screen.
>

	You could consider creating a really big bitmap, and changing the
modulo for the start of the bitmap.  This takes almost zero cpu time.  If
the bitmap is 3x the height (width) of the screen, you can do a quick blit
to copy the bottom of the screen to the top, change the modulo to the top
of the screen, and then continue.


===============================================================================
         //x                                    =  "When things are blackest,
        /// \	Try:  33014-18@sjsumcs.SJSU.EDU =  I just tell myself `cheer
       ///   \                                  =  up, things could be worse!'
      ///     \		Eduardo Horvath		=       And sure enough,
\\\  ///=======\ 				= 	they get worse!"
 \\\///         \				=  	     -The Great Skeeve
  \xxx           \miga. The computer for the corruptive mind.
===============================================================================
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Message-ID: <1989Nov12.203553.18251@sjsumcs.sjsu.edu>
Path: arc1-ca.pugleaf.net!utzoo!utgpu!jarvis.csri.toronto.edu!mailrus!shadooby!samsung!usc!apple!excelan!sjsumcs!33014-18
References: <993@mit-amt.MEDIA.MIT.EDU>

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Path: arc1-ca.pugleaf.net!utzoo!utgpu!jarvis.csri.toronto.edu!mailrus!shadooby!samsung!usc!apple!excelan!sjsumcs!33014-18
From: 33014-18@sjsumcs.sjsu.edu (Eduardo Horvath)
Newsgroups: comp.sys.amiga.tech
Subject: Re: Fast/smooth/easy vertical scrolling
Message-ID: <1989Nov12.203553.18251@sjsumcs.sjsu.edu>
Date: 12 Nov 89 20:35:53 GMT
References: <993@mit-amt.MEDIA.MIT.EDU>
Reply-To: 33014-18@sjsumcs.SJSU.EDU (Eduardo Horvath)
Distribution: na
Organization: San Jose State University
Lines: 23