From: brett@visix.com (Brett Bourbin)
Newsgroups: comp.sys.amiga.advocacy
Subject: Re: Some things...
Date: 28 Sep 92 16:52:58 GMT
Reply-To: brett@visix.com
Organization: Visix Software, Reston, Virginia

In article <1699@lysator.liu.se> boberg@lysator.liu.se (Stefan Boberg)  
writes:
> Karsten_Weiss@ibase.stgt.sub.org (Karsten Weiss) writes:
> 
> >1. What about the rumour that Commodore WON'T publish the informations  
how
> >   to program the A(G)A chips directly? (i.e. no new Hardware Ref.  
Manual)
> 
>   No rumor. It's a fact. (and a good decision).

IYHO.

> >   This would mean that the new chips would be 'useless' for the game
> >   producers and also for the European Demo Scene as they DON'T WANT to
> >   use the oerating system doing all the stuff for them...
> 
>   Then they will have to change their minds. The new chips are certainly
> not useless to game producers or demo programmers - they only have to
> adopt a new (and better) style of doing things. There is no real draw-
> back in using the OS to get access to the nifty features since the
> only thing you would really need them for is to initalize screens etc.
> and then you can go ahead and bang the bitmaps and blitter whichever
> way you like.

A few things, people (demo and game developers) had to go to the hardware  
BECAUSE the OS COULD NOT DO what they needed. Things like double buffering  
displays, flips within 50/60hz, instant color changes, mid-scanline Copper  
tricks, etc.

> The problem is that these `game coders' and `demo coders' 
> have this strange urge to do EVERYTHING themselves even if the OS
> provides excellent routines to do the same things.

Well, a fallout on the way the Amiga OS is developed, you almost needed to  
do this. If you took over the screen that was on thing. You still needed  
to make sure the OS didn't change your idea of the "ViewLord". Interrupt  
responce time was (is) a real problem with the OS up and running, meaning  
some stuff must be shutdown. I won't go into the speed problem on a 1.3  
A500/512K machine using the OS.

>   Another reason why game and demo programmers `had' to toss the OS and
> go straight at the hardware was that the earlier Amiga models only had
> 512K ChipMem and this could get quite tight when you start making more
> sophisticated games (there are ways around this limit however, which
> we proved in Project X and Alien Breed, who both play samples from 
> FastMemory instead of ChipMem). The AGA Amigas will come with 1M/2M 
> ChipMem minimum, so this is no longer true.

With 1MB standard, the problem will be masked some. There will be less  
size optimizations and more pre-computed images.

> >2. Is it possible to program a one-byte(or word)-per-pixel-screen-mode  
with
> >the A(G)A chips? Such a fx-mode would be VERY useful for vector gfx and  
it
> >   would as make the conversation of PC VGA games easier. However, I  
don't
> >   think it's possible. Still hoping...
> 
>   It's not available, and quite I frankly don't see the usefulness as 
> far as vector graphics is concerned...

Very useful for scaling, perspective, texturing routines, since this is  
how you deal with such data. For instance, all my texturing/scaling  
routines deal with "chunky" data and only convert to planar data in my  
Image/Sprite drawing/blitting routines.
--			 _  _    _      _
Brett Bourbin		(_ |_ | /__ | |(_  4431 Lehigh Road, Suite 151
  brett@visix.com	__)|_ |_\_/ \_/__) College Park, Maryland 20740
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Newsgroups: comp.sys.amiga.advocacy