Path: utzoo!attcan!uunet!snorkelwacker!tut.cis.ohio-state.edu!ucbvax!tekig5.pen.tek.com!wayneck
From: wayneck@tekig5.pen.tek.com
Newsgroups: comp.sys.amiga
Subject: Re: (A) Amy 500 -> 2000? (B) 68040 vs. gfx coprocessor
Message-ID: <9002131907.AA28357@tekig5.pen.tek.com>
Date: 13 Feb 90 19:07:10 GMT
References: <90Feb13.001952est.58517@ugw.utcs.utoronto.ca>
Sender: daemon@ucbvax.BERKELEY.EDU
Lines: 65


Dennis,

    Well I'm sorry if I offended you.  Still I think you are a little off the 
deep end.  You state that dittering can increase the number of colors and
then in the same breath say the TI 34010 is still limited to graphics.  How 
can you have so much vision and then lack of vision in almost the same 
statement?

    I've used dithering very effectively to enchance shading.  Some uses
of dithering do give an apparent increase in the number of colors.  However,
it is a long ways away from using a handful of colors to generate thousands
of color.  At higher resoulitions, sometimes mixing too different colors and
give a completely different third color but clearly not at the Amiga's low
resolutions.  That reminds me that worst part --- dithering reduces the 
resolution of the image.  You must be aware of that.

    Anyway as a point of interest, I can display NewTek's images just fine
with my code.  However no one that I know of yet can handle my 24 bit rendered
output in the Amiga high-res. mode.  I've been forced to go to a enchanced
HAM mode just to get a reasonable display.  Even that mode leaves a lot to
be desired.  One of the biggest problems is that the Amiga's 4 bit DAC      
resolution is also very limiting.  Believe me I using a much dithering as
it is possible. 

    Besides, today color is one of the easiest things to add, memory is cheap,
DACs are cheap, and reasonable coprocessors aren't that expensive.  By the 
way you seem to be using very old prices.  We looked at the TI chips a couple
of years ago for a project and the pricing then was only around $175 a chip
for the 20MHz version.  Currently the chip must be much lower, I'm sure the 
largest cost of a TI 34010 based system will be the RAM, it least it was then. 

     Now let me asure you, that if the system you are working on has a 
resonable amount of memory for programming the TI 34010 is truely very general
purpose.  A few years ago I worked on a oscilloscope project that used a 6802 
processor.  It even has a multi-tasking kernal in it and with the help of
complex tables does an amazing amount of realtime computations.  The TI 34010
instruction set is much more powerful and useful than the 6802 instuction set.
If you can call a 6802 a general purpose processor you can cretainly call a
TI 34010 a general purpose processor.

     I may have a different prespective than you since while I do a very large
amount of software, I'm a electrical engineer by education.  I do a great deal
of software that enable a processor to work with custom hardware.  Anyway that
has given me a large amount experience with making chips do things they weren't
primarly designed for. 

     On the Amiga side I wrote a program called Amination:Titler which uses
the blitter most of the time.  I had to write my own low level interface since
the Amiga Intuition doesn't allow full access to the blitter hardware.  Even
so I'm unimpressed with the Amiga's blitter.  There just isn't much there and
it doesn't run nearly as fast as people think.  I had to pull every trick in
the book to achive smooth continous scrolling which by the way uses nearly
100% of the copper, blitter, and avaible CPU to pull off.  Anyway my blitter
calls run over 3 times faster than the Amiga Intuition calls and still it isn't
very fast.  There is this line that the Amiga custom chips are the fastest
graphics chips in the world --- that may have been true in 1985 but it sure
isn't today.

                                                 Cheers!
                                                   Wayne Knapp

PS. You should look at a software blitter, you may be shocked by how little
code it uses.  As I've said I've seen a blitter routine that live in a 
68020's 256 byte cache that can turn memory just as fast as it can go.