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Article #1028Blitter question
From: Francois Rouaix
Date: Sun, 27 Aug 1989 11:11
Date: Sun, 27 Aug 1989 11:11
23 lines
1350 bytes
1350 bytes
Hello,
Yet another question from a friend that does not have access here:
Using the blitter in line mode, I have problems with diagonal lines.
The start point of the line is always shifted vertically by two pixels,
upwards or downwards, depending on the increment/decrement mode.
Do you have a hint on which register is badly programmed ?
PS: I used the notes of the European Devcon (article by Tomas Rokicki)
and the hardware manual. It seems that there is a typo in the Devcon
notes, page 13, line 2.
blit.cpt=blit.dpt=m + ((x1>>3) & ~1) + y * (wx >> 3)
^^^
Use wy instead of y
Thanks to anybody that can give a hint !
--
*- Francois Rouaix // We are all prisoners here, *
*- rouaix@inria.inria.fr \X/ of our own device *
*- SYSOP of Sgt. Flam's Lonely Amigas Club. (33) (1) 39-55-84-59 (Videotext) *
Disclaimer: Opinions expressed are my own, not those of my employer.
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Path: arc1-ca.pugleaf.net!utzoo!attcan!uunet!mcsun!inria!rouaix From: rouaix@inria.inria.fr (Francois Rouaix) Newsgroups: comp.sys.amiga.tech Subject: Blitter question Keywords: line mode Message-ID: <1387@inria.inria.fr> Date: 27 Aug 89 11:11:49 GMT Organization: FR.A.U.G. Lines: 22