' =================================================================
' Program Name : BMPREAD.BAS
' Programmer   : B. Kahl
' Date         : February 28, 1996
' Description  : This program will load a Windows 3 bitmap graphics
' file and display it.  generally written for 16color 480x640 screen
' 12 modes.  This is a primative version with slow disk read. (reading
' each pixel line 320 bytes per disk access)  Future versions will
' load larger amounts of pixel data during a single disk access.
'
' Written w/PowerBASIC assisted by Dave Navarro, Jr., Gary J. Sibio,
' and John Pearson
' =================================================================

     cls
     f1% = freefile
'     filename$ = "C:\WINDOWS\BOXES.BMP"
     filename$ = "C:\WINDOWS\CHESS.BMP"

     Open filename$ for binary as f1%
     FiLen& = lof(f1%)

     Map BMPFileHdr$$ * 14,_  'Standrd BMP File Header Record=14Bytes
        2 as FType$$,_     'File Type BM or 0xD42
        4 as FSize$$,_     'File Size
        2 as Resrv1$$,_    'Not Used
        2 as Resrv2$$,_    'Not Used
        4 as OffSet$$      'Offset to Beginning of Data

     seek #f1%,0               'start of BMP
     get$ #f1%,14,BMPFileHdr$$ 'Read stndrd MBP File Header 14 bytes

     if FType$$ <> "BM" then print Ftype$$;"File Not BMP Format Cannot Display":end

     FSize&=cvl(FSize$$)
     OffSet& = cvl(OffSet$$)  '3E = Mono, 76=16 Clr, 436=256 Clr, 36=16.7mil
'                              62dec    , 118dec   , 1078       , 54dec

     Map BMPInfoHdr$$ * 40,_   'Standrd BMP Info Header Record=40Bytes
        4 as Size$$,_          'Len of the header in bytes
        4 as Wid$$,_           'Width of the image in Pixels
        4 as Height$$,_        'height of the image in Pixels
        2 as Planes$$,_        'Num of Planes (min =1)
        2 as BitCnt$$,_        'Bits per Pixel 1,4,8,24
        4 as Comprsn$$,_       'comprsn Scheme 0=none,RGB,RLE8,RLE4
        4 as SizeImage$$,_     'size (bytes) of the bits in image
        4 as XpelsPerMeter$$,_ 'horz Res in Pixels per Meter
        4 as YpelsPerMeter$$,_ 'Ver Res in Pixels per Meter
        4 as ClrUsed$$,_       'Num of Colrs Used 0=max
        4 as ClrImprtnt$$      'Num of Colr Indexes considrd imptnt 0=all

     get$ #f1%,40,BMPInfoHdr$$ 'Read stndrd MBP Info Header 40 bytes

     size&  =cvl(size$$)
     wid%   =cvl(wid$$)
     height%=cvl(height$$)
     Planes%=cvi(Planes$$)
     BitCnt%=cvi(BitCnt$$)

print "File Name$     = ";FileName$
print "FileSize       =";FSize&
print "Offset to Data =";OffSet&
print "Header Size    =";size&
print "Image Width    =";wid%
print "Image Height   =";height%
print "Planes         =";Planes%
print "Bits Per Pixel =";BitCnt%
Print "Press any Key to Continue"
input a$

      Map RGB$$*4,_           'Color Values
        1 as Blue$$,_         '0-255
        1 as Green$$,_        '0-255
        1 as red$$,_          '0-255
        1 as rsrvd$$

     screen 12                 'VGA screen mode 12 16 colors 640x480
                               'this line has to be prior to setting palette
     cls
     for i%=0 to 15
       get$ #f1%,4,RGB$$       'Read RGB Values start at 54 bytes from start 0-255
       Blue?= cvbyt(Blue$$)\4  '1 byte containing Blue Value from file convert to 0-63
       Green?=cvbyt(Green$$)\4 'ditto             Green
       Red?  =cvbyt(red$$)\4   'ditto             red
       reg 1, &h1010           'AX set individual DAC register 5-21 PC Interrupts
       reg 2, i%'p%\256           'BX Register Number from BH
       reg 3, Green?*256+Blue? 'CH=Green, CL=Blue 0-63
       reg 4, Red?*256         'DH=Red 0-63
       call interrupt &h10
     next i%

      seek #f1%,offset&                'offset pnt read from BMP File header
      for y% = height%-1 to 0 step -1  'bottom screen line first in file
        get$ f1%,wid%\2,buf$           'read 1 line data from file @ a time
        for x%=0 TO wid%-1 step 4      'build array from string
          pix??= cvwrd(mid$(buf$,(x%\2)+1,2))  'convert 2bytes string to array val
          ms? = pix??\256              'most significant 8 bits
          ls? = pix?? mod 256          'least significant 8 bits
          pset (x%+2,y%),ms?\16        'most significant 4 bits
          pset (x%+3,y%),ms? mod 16
          pset (x%  ,y%),ls?\16
          pset (x%+1,y%),ls? mod 16    'least signif
          if instat then exit,exit     'exit loop when any key pressed
        next x%
      sound 50,.001
      next y%
      close #f1%
      end