Path: utzoo!mnetor!uunet!husc6!mailrus!nrl-cmf!ames!oliveb!amiga!boing!dale
From: dale@boing.UUCP (Dale Luck)
Newsgroups: comp.sys.amiga
Subject: Re: Scrolling a single plane -- heart monitor
Message-ID: <110@boing.UUCP>
Date: 15 Mar 88 16:27:15 GMT
References: <2143@mit-amt.MEDIA.MIT.EDU>
Reply-To: dale@boing.UUCP (Dale Luck)
Organization: Boing, Milpitas, Ca.
Lines: 16
Keywords: horizontal scrolling electrocardiogram

In article <2143@mit-amt.MEDIA.MIT.EDU> dlleigh@media-lab.UUCP (Darren L. Leigh) writes:
>Is it possible to horizontally scroll only one plane out of a
>multi-plane bitmap?  How quick is horizontal scrolling?  I mean
>actually moving all that data, not just moving a pointer.  What would
>be the best way to do this?  Any and all ideas are appreciated.
Set up a screen in dual play field mode. Make one of the bitmaps about twice
as wide as the screen. When you want to shift that playfield to the left
increment RxOffset in the RasInfo. Call MakeScreen, Rethink DIsplay, or
try using ScrollVPort. When you get to the middle though you will have to
copy the righthand side over to the left hand side and start back with
RxOffset = 0. Otherwise you will spiral down through your bitmap.
Hope this helps.
There are trickes necessary to create a dualplayfield screen, you have to
create it as a standard screen and then convert it yourself into dual
playfield.
Dale Luck