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From: ewhac@well.UUCP (Leo 'Bols Ewhac' Schwab)
Newsgroups: comp.sys.amiga
Subject: Re: Bitplanes from Hell (was: Re: Wishlist for A3000)
Message-ID: <4539@well.UUCP>
Date: Thu, 26-Nov-87 03:56:16 EST
Article-I.D.: well.4539
Posted: Thu Nov 26 03:56:16 1987
Date-Received: Sun, 29-Nov-87 16:09:20 EST
References: <1112@sugar.UUCP> <34828@sun.uucp>
Reply-To: ewhac@well.UUCP (Leo 'Bols Ewhac' Schwab)
Organization: A little; I'm getting better.
Lines: 37
Summary: Halfbrite has limitations.
Spam-Content: High.  So what are ya gonna do about it?


In article <34828@sun.uucp> cmcmanis@sun.UUCP (Chuck McManis) writes:
>In article <1112@sugar.UUCP> peter@sugar.UUCP (Peter da Silva) writes:
>>You can currently get 32 shades of grey by using extra-halfbrite. 
>
>Using what palette? I can get 8 new shades in the lower ( <8 ) intensities :
>
>15/2 = 7.5	11/2 = 5.5	7/2  = 3.5	3/2  = 1.5
>14/2 = 7	10/2 = 5	6/2  = 3	2/2  = 1
>13/2 = 6.5	9/2  = 4.5	5/2  = 2.5	1/2  = .5
>12/2 = 6	8/2  = 4	4/2  = 2	0/2  = 0
>
	BZZZTT!!  Wrong!  You don't win the car.	:-)

	Halfbrite does not fully halve the gun intensities.  It takes the
intensity for each gun and right-shifts it by one bit, and the LSB falls
into the bit bucket.  So your table really looks like this:

15/2 = 7	11/2 = 5	7/2  = 3	3/2  = 1
14/2 = 7	10/2 = 5	6/2  = 3	2/2  = 1
13/2 = 6	9/2  = 4	5/2  = 2	1/2  = 0
12/2 = 6	8/2  = 4	4/2  = 2	0/2  = 0

	Therefore, you don't get any new shades (sigh).  This is from an
old halfbrite tutorial that came from ALG.  I'm 99.9999% sure it is still
correct.

Totally Unrelated Note:
	For those who were at BADGE when I was talking about my message
port/exception problems (where I was getting multiple messages when I had
in fact only sent one), I found out what was wrong.  The problem was that
I'm a profound moron.

_-_-_-_-_-_-_-_-_-_-_-_-_-_-_-_-_-_-_-_-_-_-_-_-_-_-_-_-_-_-_-_-_-_-_-_-_-_-_
Leo L. Schwab -- The Guy who's too	ihnp4!ptsfa -\
 \_ -_	    stupid to remember to call	      dual ---> !{well,unicom}!ewhac
O----^o	    GetMsg() on the reply port.	      hplabs / (pronounced "AE-wack")
"Work FOR?  I don't work FOR anybody!  Good thing, too..."  -- Me