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From: daveh@cbmvax.commodore.com (Dave Haynie)
Newsgroups: comp.sys.amiga,comp.sys.amiga.tech,comp.sys.amiga.hardware
Subject: Re: Retargetable graphics. Temporary Stop-gaps.
Keywords: rtg,iff,24bit,video hardware
Message-ID: <16612@cbmvax.commodore.com>
Date: 17 Dec 90 22:36:29 GMT
References: <12437@life.ai.mit.edu>
Reply-To: daveh@cbmvax.commodore.com (Dave Haynie)
Organization: Commodore, West Chester, PA
Lines: 62

In article <12437@life.ai.mit.edu> rjc@wookumz.ai.mit.edu (Ray Cromwell) writes:
>[cross posted since it deals with hardware and software vendors/developers]

> The reason I'm writing this is because it will be atleast another year before
>Commodore releases any retargetable specs/libraries, but we need them now. I
>suggest that the Amiga hardware and software vendors should get together and
>work towards a temporary stop-gap for video independence. 

At least a few folks have already suggested adopting an existing standard,
such as X Windows, Postscript, TIGA, etc.  Although C= should set a standard, 
it would be far better to have two high level imaging standards, one now and 
one later, that have a chance of being cross translated, than 10 or 15 hardware
level "standards" like they have on the IBM PC, which can only be painfully 
emulated at the register level.  

>If the PC world can do it (EISA?), so can we. 

EISA is certainly a standard, though a bus standard.  The PC world is still
confused about graphics.  They just have lots of different standards, with
non-standard subvariations.

>Now I'm not suggesting running Intuition screens on video boards/frame buffers. 
>What I'm suggesting in a simple set of graphic primitives to dump IFF24 bit 
>files to framebuffers. Perhaps, a rtg.library which Commodore can replace at 
>a later date with their own. What this library might contain is calls to plot
>a pixel, plot a line, do a pattern fill, and dump a scanline. (also routines 
>to read pixels/scanlines, and request screen dimensions).

What you're really suggesting is far more than a way to dump IFF24 bit files
into framebuffers, but rather some form of retargetable imaging model.  All you
need to dump IFF files of any kind to any new board is an IFF loader for that
particular board.  A simple, retargetable imaging model is something far more
powerful, since it can be driven interactively by a program, rather than just
used to display a canned image.

>So now the Amiga is getting a myriad of video boards. I feel one way or 
>another this is going to FORCE an rtg standard. 

One would hope so.  Unfortunately, its just as possible for software people to
drive Amiga display boards individually at the register level, just as they 
do on the PC.  This would not be a good trend, and a little harder on the 
Amiga than the IBM.  IBM itself established most of the register conventions
that are emulated by the clones.  So, while they changed things around at
various levels (MDA, CGA, EGA, MCGA, VGA, etc), it wasn't until VGA (except
for Hercules) where lots of different large variations of the basic register
model existed.  C= isn't promoting this, so everyone on the Amiga is pretty
much on their own with register models for display boards.

>The Amiga is not an IBM, we just can't go poking registers on hardware boards, 
>and making drivers for each board.(like IBM programmers have to do with all 
>those cga/ega/vga/super vga/foobar enhanced vga). 

It CAN be done that way on the Amiga, but it SHOULDN'T.  Because every basic
Amiga has Graphics and Intuition libraries, and only a few have other display
cards, this hasn't happened yet except for the bundled paint, etc. programs
that come with alternate display cards.  That doesn't mean it never will...


-- 
Dave Haynie Commodore-Amiga (Amiga 3000) "The Crew That Never Rests"
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		"I can't drive 55"	-Sammy Hagar