Path: 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



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.