From: Aric.Caley@ofa123.fidonet.org
Newsgroups: comp.sys.amiga.advocacy
Subject: Re: **** A1200 Info ****
Date: 11 Nov 92 16:11:00 GMT
X-Sender: newtout 0.02 Nov  5 1992

> Organization: Dept. of Math. & Computer Science, Odense University,
> Denmark
> From: micro@imada.ou.dk (Klaus Pedersen)
> Message-ID: 1992Nov10.203013.4125@imada.ou.dk
> Newsgroups: comp.sys.amiga.advocacy
>
> bloc1469@ee.ee.uwm.edu (Gregory R. Block) writes:
> >You could also use BOBs.  You'd have to use the base 64-color
> >registers for the background and make your BOB's in ham surrounded by
> >one of the base 64 colors on one side.  But careful planning of your
> >graphics could make that indistinguishable.
>
> OK, "the background can have 64 colours, right!"
> - That is not very nice do you think so?
>  Even an A500 can do that.

First  of all, you are talking about doing games.  I dont CARE about games.
I'm  not  going to buy an A1200 based on how well it plays games!!!  If you
want  to  buy  a  Falcon 030 because it looks a little better in games (and
thats  debatable),  go  ahead!   The  rest of us Amiga owners will be doing
serious applications with our machines.

> "But the BOBS can have real HAM inside! Wow!"
> - Why not use 64 colours for the background and the 192 for the BOBS?

Because you use 64 colours for the background and 262144 for the BOBS.

> On the Falcon030 you can have 65536 colour background and 65536 colour
> 'BOBS'.
> (even though it probaly is faster to plot them with the CPU).
> (65536 colours is a differend colour to every pixel in a
> 256x256 pixel sprite!)

262144 colours is a differenT colour to every pixel in a 640 x 400 SCREEN.

The  A1200  also has sprites - and these wont disturb the HAM images.  They
can be up to 64 pixels wide.  These could prove to be pretty usefull.

> I think that the cookie-cut-sprites in Falcon030-true-colour mode is much
> faster than HAM8 AGA cookie-cut-BOBS.

What  makes  you think that?  Your blitter would have to be MORE than TWICE
as  fast  as the Amiga blitter.  Your true-colour pixels need twice as many
bits  (16  compared  to  8  for  HAM-8).  Plus, from what I understand, the
Falcon  video  DMA  causes  contention with the system when displaying true
colour..  the A1200 does not slow down the system at all when showing HAM-8
at  640  x 200/400 interlaced or less (320 x 200 for typical games).  There
is  no  way  that  "cookie-cuting"  in  the Falcon true-colour mode is much
faster than on the A1200's HAM-8 mode.

> The Falcon030 uses 1 wordaccess for each 2 truecolour pixels (written w.
> movem.l).

1 long access = 32 bits = 2 x 16 bits, for 2 "packed" true colour pixels.
You are essentialy correct, here.

> The AGA BOBS uses 4 wordaccesses per 16 bits of the BOBS.
> This is (4*8/16 = 2 wordaccesses/pixel), 4 times slower than the
> Falcon030.

?!?   This makes no sense.  The Amiga uses a planer arrangment, so you dont
write  a  single  pixel  in  one  write.   You  write  into  each  bitplane
separately.  This lets you do some handy tricks, like writing into selected
bitplanes  only.   This doesnt necessarily make it really slow..  since the
CPU will write part of 32 pixels at once.  It would take 8 long accesses (8
bits  per  pixel)  to  write  32 pixels.  That ends up being 1 "wordaccess"
(actualy a LONG access) for each FOUR pixels - TWICE as fast as the Falcon.
So you are WAY WAY off by saying the Falcon is four times faster!!


> Which one will have the fastest graphics, -and- the most colours?

So  far,  the  Falcon can have more colours on the backround, but the A1200
can have much more colours in the BOBs.  Because the Amiga uses only 8 bits
per  pixel,  instead of 16, it has half as much information to move around;
not  to  mention  needing only half as much RAM for the display and buffers
and  half  as  much disk storage.  The Amiga has no DMA video contention in
the  same  resolutions  as  the  Falcon.  The Amiga has sprites.  The Amiga
blitter  is  more  powerfull,  and  at  least as fast, as the Falcon's; and
combined with the fact that it only needs to move half as much information,
its definately going to be faster.

So I'd say, definately, that the A1200 will have faster graphics and more
colours.

>
> -Klaus

 - Dances With Coyotes - World's slowest programer -Given that the universe-
 ---------------------------------------------------is infinate, and god is-
 ------------ And the fat lady sings... ------------all powerful, would you-
 ---------------------------------------------------like some toast?       -


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