From:	cs19 AT cityscape DOT co DOT uk (BDC Client Team)
Newsgroups:	comp.os.msdos.djgpp
Subject:	Help with Allegro getpixel()
Date:	Tue, 13 May 1997 12:07:08 GMT
Organization:	IP-GOLD User
Message-ID:	<863525228.17268.0.nnrp-2.9e9829a4@news.demon.co.uk>
NNTP-Posting-Host:	itsb.demon.co.uk
Lines:	31
To:	djgpp AT delorie DOT com
DJ-Gateway:	from newsgroup comp.os.msdos.djgpp

I wonder if anyone can help me with the Allegro getpixel() function?

I am reading in a bitmap and then traversing the bitmap (left to right,
top to bottom) to determine what pixels in the bitmap are 'active' (ie
non-zero)

whatever I try to do, getpixel always returns a 0

Below is a snippet of the code I am using (p is an int, s2 is a bitmap 
containing a sprite):

 . 
 . 
 for (y1=0; y1++; y1<32) 
 {
  for (x1=0; x1++; x1<32) 
  {
   p=getpixel(s2,x1,y1);         
   if ((p!=0) && (p!=-1))                    
    {
     sprintf(msg,"Colour=%d\n", p);
     textout(screen, font, msg,0,0+(10*y1),38);
    }
   }
  }
     
Any ideas anyone?

Neil Chinnery
http://www.geocities.com/SiliconValley/Park/1077

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