Path: utzoo!utgpu!jarvis.csri.toronto.edu!cs.utexas.edu!tut.cis.ohio-state.edu!ucbvax!bloom-beacon!eru!luth!sunic!liuida!micja
From: micja@majestix.ida.liu.se (Michael Jansson)
Newsgroups: comp.sys.amiga.tech
Subject: Re: Fast Scrolling
Summary: Fast scrolling in a workbench window!?
Message-ID: <1449@majestix.ida.liu.se>
Date: 1 Dec 89 10:13:17 GMT
References: <13939@eerie.acsu.Buffalo.EDU>
Organization: CIS Dept, Univ of Linkoping, Sweden
Lines: 35


  This is a related question to the previous ones. 

  I am currently trying to implement a classic game called 'Moon lander'
  where I want to be able to scroll a landscape (implemented as a sort of
  fractal) in which a space craft should try to land.

  One of my goals is to do this inside a workbench window (It's much more
  fun to do it this way, and probably harder too ;-).

  The big prob|em with this is that I can't use ScrollVPort because I don't
  have a ViewPort with a RasInfo to modify, and that using a ScrollRaster
  would make the window flicker because the bitplanes will scroll one at a
  time and not all at once.

  In my crrent solution I create a fake RastPort which is a exact copy of
  the original RastPort in the window, except for the bitmap which only have
  one bitplane.  In this way I won't get any flicker because ScrollRaster
  will only scroll one plane and it will be much faster then with the
  original RastPort, BUT I only have two colors to play with now.


  THE BIG QUESTION: Is there a better way to scroll a window in the
  Workbench Screen (better == faster, using all colors and no flicker)?  I
  assume that this could be done with the coper or blitter, but what about
  concurrency of other windows on the Workbench screen (I heard that
  LockLayer and LockIBase have a few bugs!? ;-)



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