delorie.com/archives/browse.cgi   search  
Mail Archives: djgpp/2001/07/04/01:15:11

From: "Matt" <para AT tampabay DOT rr DOT com>
Newsgroups: comp.os.msdos.djgpp
References: <bwS_6.65731$_T2 DOT 17269145 AT typhoon DOT tampabay DOT rr DOT com> <426926da DOT 0106290713 DOT 1e79eb2c AT posting DOT google DOT com> <2j7%6.60987$WB1 DOT 17947770 AT typhoon DOT tampabay DOT rr DOT com> <9hpbse$bee$1 AT nets3 DOT rz DOT RWTH-Aachen DOT DE>
Subject: Re: DPMI problem
Lines: 30
X-Priority: 3
X-MSMail-Priority: Normal
X-Newsreader: Microsoft Outlook Express 5.50.4522.1200
X-MimeOLE: Produced By Microsoft MimeOLE V5.50.4522.1200
Message-ID: <pqx07.85803$WB1.23437001@typhoon.tampabay.rr.com>
Date: Wed, 04 Jul 2001 05:01:09 GMT
NNTP-Posting-Host: 65.32.103.94
X-Complaints-To: abuse AT rr DOT com
X-Trace: typhoon.tampabay.rr.com 994222869 65.32.103.94 (Wed, 04 Jul 2001 01:01:09 EDT)
NNTP-Posting-Date: Wed, 04 Jul 2001 01:01:09 EDT
Organization: RoadRunner - TampaBay
To: djgpp AT delorie DOT com
DJ-Gateway: from newsgroup comp.os.msdos.djgpp
Reply-To: djgpp AT delorie DOT com

"Hans-Bernhard Broeker" <broeker AT physik DOT rwth-aachen DOT de> wrote in message
news:9hpbse$bee$1 AT nets3 DOT rz DOT RWTH-Aachen DOT DE...
> Matt <para AT tampabay DOT rr DOT com> wrote:
> [...]
> > I cannot use the movedata functions, which I have already looked into.
The
> > game writes direct to video hardware,
>
> It shouldn't. At least not directly, all the time. Note that access to
> video memory is noticeably slower than to main memory, usually.  This
> is especially true for reading from video memory.  I.e. before you
> even _think_ about reading anything back out of the graphics card's
> memory, switch to an invisible framebuffer in main RAM and
> bitblitting.  And for this blitting operation, movedata() is just
> about perfect --- you'll hardly manage to beat it.
>
> --
> Hans-Bernhard Broeker (broeker AT physik DOT rwth-aachen DOT de)
> Even if all the snow were burnt, ashes would remain.

There is a big difference between "shouldn't" and "does", and since I didn't
write this code, "does" is quite operative. It doesn't read vram
fortunately, but it does write directly to vram. The code is poorly
organized, and the only hope I have of fixing it is direct access to some
buffer. I would prefer to back buffer because of the obvious speed
advantages if I have to read it back, however I've yet been unable to figure
out how the entire system works, so that's not a possibility either.


- Raw text -


  webmaster     delorie software   privacy  
  Copyright © 2019   by DJ Delorie     Updated Jul 2019