From:	"sl" <junk AT bbs DOT darktech DOT org>
Newsgroups:	comp.os.msdos.djgpp
Subject:	Allegro, VESA - help
Date:	Mon, 03 Jan 2000 05:40:28 -0500 (EST)
Organization:	Posted via Supernews, http://www.supernews.com
Lines:	25
Message-ID:	<fyoofqnexgrpubet.fnr9ng0.pminews@nntp.generation.net>
X-Complaints-To:	newsabuse AT supernews DOT com
X-Newsreader:	PMINews 2.00.1205 For OS/2
MIME-Version:	1.0
To:	djgpp AT delorie DOT com
DJ-Gateway:	from newsgroup comp.os.msdos.djgpp
Reply-To:	djgpp AT delorie DOT com

Hi,

	I'm writting my own GFX lib and the VESA 1.2 spec is beginning to
really piss me off :) I need the following clarified:

	According to the VESA spec, Memory Windows can be moved by increments
called WinGranularily. These windows move across Memory Banks.. Now,
according to this model, I could have a memory window spanning multiple banks
and there is no indication that BankSize=WinGranularity*1024.. However,
everywhere I look (included in DJGPP's sample VESA code and Allegro itself) I
see this assumption being made.. Why? Furthermore, according to the VESA
specs, BankSize=0 under certain modes (640x400x8bit being one of them, which
I am using to do my testing). This simply indicates that the entire VRAM is
one big bank. However, when I tried putting this to practice, I still ran
into multiple banks (trying to write past a certain range of pixels showed
the bank being 'cut off') ..

	Anyway, I'm very confused and would appreciate any help anyone can
offer me. Especially from the author of Allegro :)

Cheers,

Gili

- Raw text -