From:	"A. Sinan Unur" <sinan DOT unur AT cornell DOT edu>
Newsgroups:	comp.os.msdos.djgpp
Subject:	Re: Kinda long bitmap question...
Date:	Mon, 22 Dec 1997 13:29:21 -0600
Organization:	Cornell University
Lines:	33
Sender:	asu1 AT cornell DOT edu (Verified)
Message-ID:	<349EBF91.EAF@cornell.edu>
References:	<349ea65f DOT 126291690 AT news DOT earthlink DOT net>
Reply-To:	sinan DOT unur AT cornell DOT edu
NNTP-Posting-Host:	facilityk-dns.human.cornell.edu
Mime-Version:	1.0
To:	djgpp AT delorie DOT com
DJ-Gateway:	from newsgroup comp.os.msdos.djgpp

Jaster wrote:
> 
> Ok.. in 320x200 graphics mode, I want to have a buffer[64000] that I
> can copy to a BITMAP * using memcpy.. for example
> 
> memcpy(bitmap->line[0],buffer,64000);
> 
> now my question is.. when I fill buffer[64000] with the int 4 and then
> memcpy it to a bitmap (320x200) that I have previously made.. instead
> of filling the whole bitmap with the color red.. it only fills
> everyother verticle line with red.. I'm not trying to use this as a
> clear_to_color() but I eventually hope to edit the buffer[64000]
> thereby being able to edit the bitmap...
> 
> I hope I put this clearly enough.. If you need to see the source I'm
> using I can post it.. it's not very long.. any help and source code is
> greatly appreciated... thanks
> 

an int is 32 bits = 4 bytes. each pixel in the mode 13 screen
corresponds to a byte. if buffer is an array of int, each element will
be 0x00000004, i.e. 3 consecutive black pixels followed by a red one.

two requests from everyone:

  + especially if you are posting something off-topic, please think a
little before posting. 

 ++ by all means, please provide the smallest piece of code that
exhibits the problem. could you not have at least specified whether
buffer was an aray of int or char?

  -- Sinan

- Raw text -