Path: utzoo!utgpu!water!watmath!clyde!att!ucbvax!bloom-beacon!mit-eddie!killer!ltf
From: ltf@killer.DALLAS.TX.US (Lance Franklin)
Newsgroups: comp.sys.amiga.tech
Subject: Re: WaitTOF in interlace mode
Message-ID: <4906@killer.DALLAS.TX.US>
Date: 24 Jul 88 10:20:33 GMT
References: <4860@killer.DALLAS.TX.US> <2596@amiga.UUCP> <3379@cadnetix.COM> <2622@amiga.UUCP>
Reply-To: ltf@killer.DALLAS.TX.US (Lance Franklin)
Organization: The Unix(R) Connection BBS, Dallas, Tx
Lines: 52

In article <2622@amiga.UUCP> jimm@cloyd.UUCP (Jim Mackraz) writes:
>In article <3379@cadnetix.COM> childs@cadnetix.COM (David Childs) writes:
>)In article <2596@amiga.UUCP> jimm@cloyd.UUCP (Jim Mackraz) writes:
>)<Your trick would probably do everything twice, for both bitplanes,
>)<whether the bitplanes were at the same address or not.  You need to lie
>)<about either the BitMap.Depth or the RastPort.mask to get rendering
>)<to only do one plane.
>)
>)I believe Lance was saying he uses a different RastPort structure with a depth
>)of ONE point to the same single plane the other RastPort points to twice, and
>)then uses the second different RastPort to do the blit.  

Yup..Exactly what I do..I thought about using mask, but I didn't want to take
the chance of making an error and writing to the same bitmap twice (or to a
non-existant plane).  Doing it this way let me use all the ROM Kernal routines
that use RastPorts and BitMaps without worrying about anything else.

>Well, I didn't see the key phrase 'with depth equal to one.'  My comments
>apply to bitmaps with multiple pointers pointing to the same bitplane.

Whoops...sorry, didn't make myself clear the first time.  I definately create
a SECOND RastPort and BitMap structure, both with a depth of one, then use those
to do the rendering.  Duplicating the plane pointer in the window ensures that
the window displays the bitmap I'm rendering to.      
 
>Maybe I don't see what the plans for the bitmap with multiplicity was.
>It's perhaps a way of tricking Intuition rendering to restrict itself to
>a single plane, but the more standard way would probably be the rastport
>mask.  It depends on how you want to collapse 4 colors to 2, I guess.

Yeah...the problem with duplicating the bitmap pointers in the window RastPort
was that the colors you ended up with were 00 and 11...ok if you want orange
lettering on a blue background.  It was an experiment, anyway.  I tried it 
another way, doing a regular WBENCH window (no CUSTOMBITMAP) and creating the
second bitmap with a depth of 1 pointing only to the zero'th bitmap in the
window's RastPort.  Got fast rendering with colors 00 and 01, but had an 
extra plane sitting around.  Now, if I could just figure out how to use the
second plane for double-buffering, maybe I could get a REAL smooth scroll
without side-effects.  :-)

>Maybe Lance had it all figured out.

Maybe.

Lance


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