[comp.sys.amiga] 24-bit color

portuesi@tweezers.esd.sgi.com (Michael Portuesi) (03/29/90)

>>>>> On 28 Mar 90 20:36:10 GMT, seanc@pro-party.cts.com (Sean Cunningham) said:

> I don't see why nobody's made a true-color board for the Amiga yet.  The
> market IS there...the boards are even cheap on the Mac now.
>  
> Maybe I just want too much...


The Amiga and the Macintosh use two fundamentally different approaches
to its video subsystem.  The Mac uses a very general approach that
supports all kinds of video hardware, but sacrifices speed and special
features. The Amiga provides a very fast built-in video subsystem
with all kinds of special features, but does not provide system
support for other video hardware other than its own.  In essence, the
features that have made the Amiga a graphics/video powerhouse are also
the same features that are stunting its growth.

The biggest problem with developing a 24-bit board and just plugging
it into the Amiga is that the Amiga doesn't have a device-independent
graphics library.  Every Amiga application (except for games) uses the
Graphics Library; Intuition depends on it to function.  If you can't
get the Graphics Library to talk to the 24-bit board, you're stuck
hard-coding your applications to support it.  That's the way the PC
Clones deal with their video cards, and it's the Wrong Way to do
things.

Currently, the Amiga Graphics Library only supports the Amiga Chip
set.  There are two Right Ways for Commodore to bring 24-bit color to
the Amiga:


	* issue a new version of the Amiga chip set and Graphics
	  Library.  This is hard to do on current machines because the
	  CHIP RAM bus doesn't have enough bandwidth to support 24
	  bitplanes of color information.  For current machines, it
	  may be possible to expand the size of the color palette and
	  provide a Super-HAM mode that can display more than 4096
	  colors at once.  It still won't help you get more colors at
	  higher resolutions, though.  A chip set that can deliver
	  more colors at higher resolution will require an Amiga with
	  a faster CHIP RAM bus, pure and simple.


	* produce a device-independent Graphics Library, then open the
	  market for Commodore and third parties to make 24-bit video
	  boards.  You could then shop for the features you wanted and
	  have it seamlessly work with your favorite software.


The Macintosh already supports the latter approach.  This is one of
the areas where Macintosh technology is superior to that of the Amiga.
In any event, it's difficult for a third party company to bring out a
proper implementation of a 24-bit display system without Commodore
doing some ground work first.

And as always, flaming Commodore is a waste of time; I'm sure they're
way ahead of us on this issue.

				--M

-- 
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\/  Michael Portuesi   Silicon Graphics, Inc.   portuesi@sgi.com