From: sfranke/druid- <franke AT eden DOT com>
Newsgroups: comp.os.msdos.djgpp
Subject: having trouble w/ bitmaps in vbe2.0
Date: Thu, 26 Sep 1996 22:45:49 -0600
Organization: Adhesive Media, Inc.
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Message-ID: <324B5BFD.7CF2@eden.com>
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To: djgpp AT delorie DOT com
DJ-Gateway: from newsgroup comp.os.msdos.djgpp

I'm having trouble getting a bitmap loaded and displayed w/ vbe2.0 under
djgpp.  I know this isn't really hard to do (I can do it in real mode
assembler ;) ), but I'm just getting started with djgpp...

I'm using vbe2.0 linear 640x480x8bit.  Most of the code comes from the
vbetest.c file.  I think the problem may have to do with a misuse of
pointers or something.  Or maybe I'm loading the file wrong (I'm using
the same format and method I used for asm).  The palette isn't working
right either...  I'm not sure.. here's excerpts of what I think is
fairly important.  I can email/post the full source if you want it -
it's just one small file..

any help (even just glancing at this) is very much appreciated :)

s.franke/druid-

-----------------------------------------------------------

typedef struct {
	unsigned char r;
	unsigned char g;
	unsigned char b;
} rgbpal;

void drawPic( unsigned char image[65535], unsigned char *vid, int l, int
w, int x, int y);

void set_palette(int entry,int r,int g,int b)
{
   outportb(0x3c8,(BYTE)entry);
   outportb(0x3c9,(BYTE)r);
   outportb(0x3c9,(BYTE)g);
   outportb(0x3c9,(BYTE)b);
}

====IN MAIN====

   unsigned char thepic[65535];
   unsigned char      junk[32];
   rgbpal             pal[256];

fp = fopen("gfx.raw" , "r" );
  fread( junk  , 1, 32, fp );      // has a 32 byte header
  fread( pal   , 1, 768  , fp );   // 768 bytes for the palette
  fread( thepic, 1, 65535, fp );   // a 256 * 256 picture
  fclose( fp );
  for( i=0 ; i<256 ; i++ )
    set_palette(i,(int) pal[i].r/4,(int) pal[i].g/4,(int) pal[i].b/4);

  drawPic(thepic,video,256,256,0,0);

====this is the function for drawing====

void drawPic( unsigned char image[65535], unsigned char *vid, int l, int
w, int x, int y)
{
 int picind = 0;
 int scrind = x * y;
 int pixcnt = 0;
 int xoffset = 640 - l;
 int horiz = 0;
 unsigned char pixel;
 while( pixcnt < l * w )
 {
  pixel=image[picind];
  vid[scrind]=pixel;
  scrind++;
  picind++;
  pixcnt++;
  horiz++;
  if(horiz == l)
  {
   horiz=0;
   scrind+=xoffset;
  }
 }
 return;
}