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From: rmh@apple.com (Rick Holzgrafe)
Newsgroups: comp.sys.mac.games
Subject: Re: Games coprocessor for the Mac (was Re: Risk)
Message-ID: <11467@goofy.Apple.COM>
Date: 7 Dec 90 20:10:40 GMT
Sender: usenet@Apple.COM
Organization: Apple Computer, Inc.
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References:<15722@reed.UUCP> <17578@hydra.gatech.EDU> <5963@uqcspe.cs.uq.oz.au> <17743@hydra.gatech.EDU> <10844@ur-cc.UUCP>

In article <10844@ur-cc.UUCP> mek4_ltd@uhura.cc.rochester.edu (Mark Kern) 
writes:
> Why do Mac games use quickdraw commands for their graphics?  It would 
seem
> that it would be much faster to a) find out where screen memory resides 
on
> a particular machine. b) reserve that memory for the application. c) Use
> assembly language routines that write directly to the screen.

All that gets you is a guarantee that your game will break sometime down 
the line, on new hardware or new system software. It's hard to out-draw 
QuickDraw (on a Mac's hardware, anyway!) QD is written in assembler, uses 
excellent algorithms, and is optimized to hellandgone (wherever that is). 
It's true that trap calls are expensive; but you needn't make many for the 
kind of stuff you're talking about, which would be mostly copying bitmaps 
around. If you're still worried about trap overhead, you can (at run-time) 
learn the actual addresses that the traps trap to, and call the routines 
directly. (This technique also may break in some future system, but it has 
worked for a long time. Things that bypass QuickDraw break regularly.)

A machine with hardware and software designed for arcade-style animation 
will probably out-perform the Mac every time (just my guess; I'm no expert 
in these things). If what you want most from your machine is arcade games, 
you may well be better off with an Atari or an Amiga (or a Nintendo). The 
Mac can do that kind of stuff, but it doesn't seem to be the Mac's strong 
suit.

Just my opinion.

==========================================================================
Rick Holzgrafe              |    {sun,voder,nsc,mtxinu,dual}!apple!rmh
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