'===========================================================================
' Subject: SMOOTH MODE13H TEXT SCROLLER      Date: 01-14-98 (21:45)       
' Author:  The ABC Programmer                Code: PB                     
' Origin:  voxel@freenet.edmonton.ab.ca    Packet: GRAPHICS.ABC
'===========================================================================
'=====================[ Mode 13h TEXT Scroller ]=======================
' Scrolls using an 8x8 Character Font (more like 16x16)
' Programmed by William Yu (1-14-98) for PowerBASIC
'
' I don't know who wrote the original Pascal code, but I used that as
' my basis for this demo.  I had to use 16x16 for it to work properly
' but at the moment I don't know why... if you can tell me, that would
' really be appreciated!  This code is Public Domain.
'======================================================================
DEFINT A-Z
DIM FOFS AS SHARED WORD, FSEG AS SHARED WORD
DIM Bits (0 TO 7) AS SHARED BYTE
DIM ColTab (0 TO 15) AS SHARED BYTE
DIM ScrT AS SHARED STRING
DIM Position AS SHARED BYTE

FOR I = 0 to 7
  READ Bits(I)
next I
FOR I = 0 to 15
  READ ColTab(I)
next I
DATA 128,64,32,16,8,4,2,1
DATA 1,1,9,9,3,3,11,11,3,3,9,9,1,1,9,3,1
ScrT =" Hi folks, this scroller was brought to you by William Yu "
ScrT=ScrT+"with the help of some Pascal code!                    "

GetFont
Mode13h

  Position = 1

  Mode13h
  GetFont
  DO
    Scroll
  LOOP UNTIL INKEY$<>""
  TextMode
end


SUB Scroll
 DIM I AS WORD,J AS WORD,A AS WORD
 DIM CharPos AS BYTE,Character AS BYTE
 DIM Colour AS BYTE
 DIM Addr AS WORD,COL AS BYTE

    Character = ASC(MID$(ScrT,Position,1))
    for CharPos = 0 to 7
      for I = 0 to 15
        DEF SEG = FSeg
        Addr = PEEK(Fofs+(Character*16)+I)
        IF (Addr AND Bits(CharPos)) <> 0 then
          Colour = ColTab(I)
        else
          Colour = 0
        end if
        DEF SEG=&HA000
        POKE ((23*8)+I)*320+319, Colour
      next I
      WAIT &H3DA,8
      DEF SEG=&HA000
      for J = 0 to 15
        for I = 0 to 318
          A=((23*8)+J)*320+I
          Col = PEEK(A+1)
          POKE A,Col
        next I
      next J
    next CharPos
    incr Position
    if Position = len(ScrT) then Position = 1
END SUB

SUB TextMode
  ! mov AX, &h3
  ! int &h10
END SUB

SUB Mode13h
  ! mov AX, &H13
  ! Int &h10
END SUB

SUB GetFont
  ! push bp
  ! mov ax,&H1130
  ! mov bh,6
  ! int &H10
  ! mov fseg,es
  ! mov fofs,bp
  ! pop bp
END SUB