Path: chuka.playstation.co.uk!scea!greg_labrec@interactive.sony.com
From: Pradip Fatehpuria <pradip_fatehpuria@interactive.sony.com>
Newsgroups: scea.yaroze.programming.gnu_compiler
Subject: Re: Good value for seeding the RNG
Date: Tue, 27 May 1997 10:37:30 -0700
Organization: Sony Computer Entertainment America
Lines: 32
Message-ID: <338B1BDA.A53@interactive.sony.com>
References: <5mcp8h$shk3@scea>
NNTP-Posting-Host: 206.41.6.40
Mime-Version: 1.0
Content-Type: text/plain; charset=us-ascii
Content-Transfer-Encoding: 7bit
X-Mailer: Mozilla 3.0 (Win95; I)

Paul Kearns wrote:
> 
> This doesn't really have anything to do with the GNU compiler, but it doesn't
> have anything to do with graphics or sound, either.  Maybe a
> "programming.misc", "programming.other", or something newsgroup?
> 
> Anyway, I'm looking for a decent number to seed the random number generator
> with.  I've always used the real time clock when working with computers, but
> there doesn't appear to be such a thing on the Playstation.
> 
> I thought about measuring the amount of time it takes for the user to press a
> key, but that doesn't help for the opening animation or non-interactive
> demos.  All of the other volatile numbers, like clock ticks since program
> start or number of vertical blanks since last VSync(), seem like they'll be
> the same for each run.
> 
> Is there a location that will always (or even usually) contain a different
> number each time the Playstation's powered up??  If I read a pixel out of the
> frame buffer without drawing anything, will that be random or zero (and can I
> even do that)?  What about the current horizontal line being drawn or
> something?
> 
> Thanks,
> Paul Keanrs
> paulk@anon.nymserver.com


You can Vsync(-1) to feed the random seed and it gives it preety decent
random number generation.  I used it in Survival which places the wooden
planks randomly when you startup the game.

Pradip K Fatehpuria