Path: chuka.playstation.co.uk!news
From: philip gooch <philg@easynet.co.uk>
Newsgroups: scee.yaroze.beginners
Subject: Re: Getting a sprite to leave a trail
Date: Fri, 29 May 1998 14:14:42 -0700
Organization: PlayStation Net Yaroze (SCEE)
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Craig Graham wrote:
> 
> Elliott Lee wrote:
> 
> > The only problem with that is that the previous impressions of the
> > sprite don't fade out.  :(
> >
> > Phil, I take it that you're trying to do some kind of motion blur?
> > If so, I'd take your sprite and make about 4 or 5 copies of it at
> > about 20%-35% intensity and semitransparent.  The overlapping
> > transparent sprites will make the ones closer to the middle of the
> > trail a bit brighter and the ends a little darker.  Then put a
> > non-semitransparent copy of the sprite over the "head".  That
> > shouldn't take up too much GPU time.
> >
> 
> The same approach works on 3D objects as well, just draw a fewcopies with the
> transparency bit set, clear it and draw again - as
> the last thing sorted is drawn first if all objects are level, the final
> 'solid' image will be drawn last (ie. on top).
> 
> If you want a better effect (only easy with sprites), then use the RGB
> scaler to fade out the trailing images as well.....

Thanks guys

So its multiple sprites then to handle the trails. I should be able to 
handle that.

But anyone know how certain other effects are done - for instance I've 
seen Yaroze games where the whole screen melts away, starting from the 
centre. Is there a way of addressing individual pixels in the frame 
buffer to shift them around, apply different transparencies and RGB 
values to them etc to create this effect?

Phil