Path: chuka.playstation.co.uk!news
From: SCEE Developer Support <dev_support@interactive.sony.com>
Newsgroups: scee.yaroze.programming.3d_graphics
Subject: Re: Perplexing question
Date: Thu, 24 Apr 1997 11:15:32 +0100
Organization: Sony Computer Entertainment Europe
Lines: 34
Message-ID: <335F32C4.354E@interactive.sony.com>
References: <335E7E32.30C9@micronetics.com>
NNTP-Posting-Host: 194.203.13.10
Mime-Version: 1.0
Content-Type: text/plain; charset=us-ascii
Content-Transfer-Encoding: 7bit
X-Mailer: Mozilla 3.01 (Win95; I)

Jim wrote:
> 
> Here's a strange one fer you all.
> 
>         I was tweaking my world editor last night can
>         came across this.
> 
>         I though I had introduced a serious bug, but..
> 
>         I was drawing around 100 flat textured quads all at identical
>         coordinates.  Basically 100 poly on top of each other,
>         and the frame rate was awful.  Really crawling.
> 
>         But if I lay the polys edge on so I get a 10 x 10 playing
>         field, it trotts along at 50 fps no prob.
> 
>         Now this has me a little perplexed.  I have it working as it
>         should now, but why did it go soooo slowly when each poly
>         was at the same coords?
> 
> `       The only thing I can think of is that each poly occupied the
>         same slot in the order table.
> 
>         Does this make sense?  Ideas anyone?
> 
>         Jim

The reason for the slow down is the repeated screen draws. It all
depends on the size of the polygons you are using. By drawing a large
polygon on the screen many times the frame rate does drop, but with a
small polygon there is no problem. But again this depends on the number
of polygons.

Stuart