Path: utzoo!utgpu!news-server.csri.toronto.edu!cs.utexas.edu!uunet!munnari.oz.au!metro!ipso!fawlty!johnmac
From: johnmac@fawlty.towers.oz (John MacLean)
Newsgroups: comp.sys.apple2
Subject: Re: Animation
Keywords: Animation
Message-ID: <557@fawlty.towers.oz>
Date: 26 Apr 91 05:40:27 GMT
References: <1991Apr17.061057.22357@cs.uow.edu.au>
Reply-To: johnmac@fawlty.ips.oz (John MacLean)
Organization: Tower Technology, Lane Cove, NSW, Australia
Lines: 35

In article <1991Apr17.061057.22357@cs.uow.edu.au> u9050728@cs.uow.edu.au (Shane Kelvin Richards) writes:
>	Hello. I am hoping someone can help me. I am developing a set of
>animation routines for the //GS. So far its okay, BUT things are becoming
>a tad slow when many objects are on the screen. Heres how I am doing it..
> [LDA / AND / ORA / STA instruction sequence deleted]
>       My question is, is my basic ideas/techniquie correct? Am I using
>the wrong method for fast shape manipulation. OR am I using the correct
>method and I should just try to improve upon my code and optimise where
>I can?
>      For simplicity I only let shapes move by 2 pixels so that they 
>always fall on a byte boundary. Also, I am usin the 320x200 resolution.
>	Any ideas, what other techniques are there?
>+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-
>Shane Richards
>u9050728@cs.uow.edu.au
>+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-

At this level there is nothing wrong with the technique you are using.
One thing you can do is use the //ec softswitches, and to move zero page
up to the super hires screen.
Of course, this can be a bit nasty if your using GS/OS / interrupts / etc.
Make sure you're using the most optimal addressing modes, you have
the data bank set to bank 1 etc, etc.

It is also a good idea to base your animation on VBL interrups / so that
your code does not slow down as you add more and more shapes - just set
a limit that has acceptable speed, and update every 3,4,5 VBLs -
whatever seems reasonable.

John MacLean.
-- 
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