Path: chuka.playstation.co.uk!news
From: rs108@mdx.ac.uk (Robert Swan)
Newsgroups: scee.yaroze.programming.2d_graphics
Subject: Re: Animating sprites
Date: Wed, 13 May 1998 14:25:42 GMT
Organization: PlayStation Net Yaroze (SCEE)
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On 8 May 1998 20:06:26 GMT, "Martin Swaine" <martin@lightwork.co.uk>
wrote:

>To keep the thing fast the distance between each consecutive instance of
>the sprite is quite large. The problem is I am seeing a trail of several
>dimmer copies behind the current sprite. 

That sounds quite interesting. I wouldn't mind looking at the source
code to see if the same thing happens with me. There are two things
that spring to mind but Im not sure either are that likely -

1) If your game updates less than 50 times a second you get a visible
double image on screen, but with one sprite that isnt likely!

2) your eye is creating an effect that it always, presistence of
vision, whereby the eyes receptors can't cope with complete changes
from light (where the sprite is) to dark (where the sprite now isnt).
If the gaps are fairly large, then the way the brain compensates
against the receptors by emphasizing a moving object will operate less
and less, and you will tend to see seperate images switching on/off
rather than a smooth movement. But that isnt so likely either

there could be some other obvious reason, like the screen isnt getting
cleared properly and there actually is a trail, but I trust that that
isnt the case!

Robert Swan
rs108@mdx.ac.uk
http;//www.netyaroze-europe.com/~middex2