Path: chuka.playstation.co.uk!news
From: SCEE Developer Support <dev_support@interactive.sony.com>
Newsgroups: scee.yaroze.programming.2d_graphics
Subject: Re: It's just a question of time...
Date: Wed, 23 Apr 1997 08:40:14 +0100
Organization: Sony Computer Entertainment Europe
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Chris Allmark wrote:
> 
> ...well two questions actually.
> 
> The first one : is there a tick count function ( I haven't really looked
> but the manuals drive me CRAZY ) I need something to control a sprites
> frame rate.
> 
> The second one : what's is the real difference between GsSortSprite and
> GsSortFastSprite (apart from the speed as the names suggest). Can you mix
> them ? I'm working on a basic sprite animation routine, but the sprite
> flickers like hell when I use GsSortSprite - I need to use this to perform
> scaling & rotation effects.
> 
> Any Ideas ?
> 
> --
> Chris Allmark, Zoo Software Solutions
> "If you can't plug it in - We don't use it !"

You can access a fast tick ( Sysclk /8 ) using
ResetRCnt/StartRCnt/GetRCnt with RCnt2 ( in the header somewhere )

GsSortFastSprite produces GPU sprites ( very fast - Max 2pixel writes
per cycle )
GsSortSprite produces texture mapped poly's ( Max 1pixel write per cycle
) - Allowing rotation etc..

If your display is flickering you are probally drawing to the wrong
double buffer or not using 2 buffers. ( Normally the flicker is caused
by the initial clear screen being seen by the scanning CRT beam )
Or if you are using interlace ( 480/512y ) you will get flickering if
your drawing update takes more than a single field.

Cheers,


Colin.