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From: ki@opal.cs.tu-berlin.de (Karsten Isakovic)
Newsgroups: comp.sys.atari.st
Subject: Re: vro_cpyfmt() blues
Keywords: ATARI ST, GEM, VDI, C
Message-ID: <3417@quepasa.cs.tu-berlin.de>
Date: 21 May 91 13:04:50 GMT
References: <1991May21.104617.26475@informatik.uni-erlangen.de>
Organization: Technical University of Berlin, Germany
Lines: 36

In article <1991May21.104617.26475@informatik.uni-erlangen.de> lsmichae@immd4.informatik.uni-erlangen.de (Lars Michael) writes:
>I have some problems with the VDI function 'copy raster opaque'.

>  line = (Getrez()==2)?80:160;	/* get number  of Words in scanline */

Don't use Getrez(). This code will crash under nearly all graphics cards
(MATRIX, MGE, OverScan, Reflex) and even on the TT.
If you blit to / from the screen you must set fd_addr = NULL. In this
case all other values are filled in by the VDI. You can't know how many
BytesPerLine the actual graphics card has.
For the 'offscreen' MFDB, you must use w/16*planes. It does not matter if
the BPL in the offscreen area is different to the screen MFDB (As in
OverScan mode or with the Reflex card), the VDI handles this correctly.

>  src_mfdb.fd_nplanes = 4>>Getrez();

You get the plane count with the vq_extend call or in the AES global[10]
array but NOT with Getrez()!

>The routine will be entered by a call like
>copy_block(Logbase(), temp, xdial, ydial, wdial, hdial);

Don't intercept VDI and XBIOS calls. The Xbios calls are only for the
'main console' of the ST and not for a graphics card. (But most cards
have an emulation of the calls). If you use Getrez() with a Matrix card
installed, you will get the rez of the (probably not connected) ST-monitor.
With Physbase(), Setpallete, Setcolor there is the same problem.

>Now, can someone tell me, what's wrong ?

Your main 'bug' is in the pxy array. The '+3' copys more memory lines than 
possible, so you get an bus-error in the color resolution.

>  lsmichae@faui43.uni-erlangen.de  

Karsten, ki@opal.cs.tu-berlin.de    (Meet me in +Atari on IRC...)