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From: pilgrim@daimi.aau.dk (Jakob G}rdsted)
Newsgroups: comp.sys.amiga.programmer
Subject: I got  problem with overscan*interlace*PAL
Summary: got problems
Keywords: hit me before I hit you
Message-ID: <1991Jun2.183144.22881@daimi.aau.dk>
Date: 2 Jun 91 18:31:44 GMT
Sender: pilgrim@daimi.aau.dk (Jakob G}rdsted)
Organization: DAIMI: Computer Science Department, Aarhus University, Denmark
Lines: 41

OK. I got the source code for WBPic by fridhjof Siebert
(it's in modula-2).
WBPic and SimGen does practically the same thing - they put
a 2-4 colour iff pic in the background, as colour 0.
WBPic does it by making a 8-16 colour pic(using the bit-
planes from both and making a new palette). Maybe SimGen
does it the same way, I don't know.

(We are now closing in on the subject...)

I use a PAL a500. Both of these programs fail on one type
of pictures. That is, interlaced, 4colour overscan pictures.
It seems like, when one tries this, that the machine acts like
the display is NTSC.

In the description of WBPic, it says noninterlaced pictures,
but it seems to work just fine. It works if the pictures are
2colour, but does the above error, if 4colour.

I've looked through the source  code for wbpic, and see no
limitations in it(it is simple, and easy to understand; I
can mail it to you if you're interested or would look at
it). Although he uses a Ifflibrary of some sort, forgot its
name. But SimGen fails also ,so I suspect this isn't the
problem.

I don't understand what goes wrong(why does it work with
2 colours). The overscan workbench is a result of a
'mutant' system-configuration; I haven't edited the numbers
myself, so it should be okay.

I believe NTSC users to have no problems(as it seems like
using NTSC overscan with the 4colour pictures).

I hope some people get curious at this, because I have
almost given up. 
--
From the notorious
                      Jakob Gaardsted, Computer Science Department
Bed og arbejd !            University of Aarhus,  Jylland (!)
(Pray and work!)  AMIGA!  pilgrim@daimi.aau.dk | I'd rather play Moria.