Path: utzoo!utgpu!news-server.csri.toronto.edu!cs.utexas.edu!usc!apple!portal!cup.portal.com!Sullivan
From: Sullivan@cup.portal.com (sullivan - segall)
Newsgroups: comp.sys.amiga
Subject: Re: Video Toaster Info-real and current
Message-ID: <28747@cup.portal.com>
Date: 10 Apr 90 02:28:05 GMT
References: <7668@hydra.gatech.EDU> <28725@cup.portal.com>
  <1990Apr8.203857.1571@jarvis.csri.toronto.edu>
Distribution: na
Organization: The Portal System (TM)
Lines: 54

>>If anyone can help with the answers, I'd love to know.  At first glance the 
>>BlackBelt kludge sounds like a better deal for what *I* want to do.  According
>>to the specs, the maximum frame transfer rate to the Toaster is 1/5 second. 
>>Assuming that their values are optimistic even with an efficient CPU, that
>>makes for a really lousy animation.  Also from their literature, I have 
>>difficulty understanding exactly what the Toaster *is*.  At least with the 
>>BB I'd know what I'm getting, how to program it, and how to take full 
>>advantage of its capabilities.  
>
>
>what the hey is a BlackBelt? I thought I was up on all the latest toys.
>
>If this is a stupid question, then put me out of my misery and tell me,
>don't just say 'pfaugh' and skip to another article. (please)
>
>
The BlackBelt kludge is more vaporware.  Like the Toaster it has been shown
to developers, but hasn't yet been released.  IMHO it is a really sweet 
bit of engineering.  The basic idea is this:

Take a hi-res 4 bitplane screen and convert it into a lo-res 8 bitplane screen.
That gets you 256 colors, and their palette is 16million (ie 24bits).  Well
at this point the hardware was still relatively boring, so BB decided to 
make it function in a very HAM-like way.  There are two modes.  In the first
all of the color registers are accessed directly.  The actual pallette is
bank swapped for ~16 banks of 240 colors each.  That way within two pixels 
you can exactly identify 16x240 different colors (24 bits deep).  
In the second mode you modify either the Red, Green or Blue component of
the current value, using seven bit offsets, so that you can access 128 
registers directly, or modify 7 of the eight bits of Red, Green or Blue.
This mode is essentially 21bit color, although the actual registers still 
use 8 bits each (ie 24bits of color).  The first two scan lines are used
for a recognition pattern for the BlackBox, and to preload the registers.
(Registers can also be reused through the scan if you are willing to dump
several pixels at it.)  The blackbox resets whenever it detects a reset
command, or when it sees a full line of color Zero.  This means that sliding
windows will still work correctly.  Problems are:  Pull down windows 
obscure the top two lines which drops the Black Box out of its own mode, 
so any time you select a menu, the picture will become garbage.  (The menus
will look right though.  Another problem is that the bitplanes are now 
interleaved as well as separate.  Animation should be possible at the 
same frame rate as 640xANYx16 is now.
 
                           -Sullivan Segall
_________________________________________________________________
 
/V\  Sullivan  was the first to learn how to jump  without moving.
 '   Is it not proper that the student should surpass the teacher?
To Quote the immortal Socrates: "I drank what?" -Sullivan
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