{
    $Id$
    This file is part of the Free Pascal run time library.
    Copyright (c) 1993-98 by Gernot Tenchio

    Mandelbrot Example using the Graph unit

    See the file COPYING.FPC, included in this distribution,
    for details about the copyright.

    This program is distributed in the hope that it will be useful,
    but WITHOUT ANY WARRANTY; without even the implied warranty of
    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.

 **********************************************************************}
program mandel;

{
  Mandelbrot example using the graph unit.

  Note: For linux you need to run this program as root !!
}

uses
{$ifdef go32v2}
  dpmiexcp,
{$endif go32v2}
  dos,Graph;

{
const
  shift:byte=12;
}

var
  SearchPoint,ActualPoint,NextPoint       : PointType;
  LastColor                              : longint;
  Gd,Gm,
  Max_Color,Max_X_Width,
  Max_Y_Width,Y_Width                    : word;
  Y1,Y2,X1,X2,Dy,Dx                      : Real;
  Zm                                     : Integer;
  SymetricCase                                   : boolean;
  LineY                                  : array [0..600] OF BYTE;
  LineX                                  : array [0..100,0..600] OF INTEGER;
const
    SX : array [0..7] OF SHORTINT=(-1, 0, 1, 1, 1, 0,-1,-1);
    SY : array [0..7] OF SHORTINT=(-1,-1,-1, 0, 1, 1, 1, 0);
type
    arrayType = array[1..50] of integer;

{------------------------------------------------------------------------------}
  function ColorsEqual(c1, c2 : longint) : boolean;
    begin
       ColorsEqual:=((GetMaxColor=$FF) and ((c1 and $FF)=(c2 and $FF))) or
         ((GetMaxColor=$7FFF) and ((c1 and $F8F8F8)=(c2 and $F8F8F8))) or
         ((GetMaxColor=$FFFF) and ((c1 and $F8FCF8)=(c2 and $F8FCF8))) or
         ((GetMaxColor>$10000) and ((c1 and $FFFFFF)=(c2 and $FFFFFF)));
    end;

{------------------------------------------------------------------------------}
function CalcMandel(Point:PointType; z:integer) : Longint ;
var
  x,y,xq,yq,Cx,Cy : real ;
begin
  Cy:=y2 + dy*Point.y ;
  Cx:=x2 + dx*Point.x ;
  X:=-Cx ; Y:=-Cy ;
  repeat
    xq:=x * x;
    yq:=y * y  ;
    y :=x * y;
    y :=y + y - cy;
    x :=xq - yq - cx ;
    z :=z -1;
  until (Z=0) or (Xq + Yq > 4 );
  if Z=0 Then
    CalcMandel:=(blue and $FFFFFF)
  else
    CalcMandel:=(z mod Max_Color) + 1 ;
end;

{-----------------------------------------------------------------------------}
procedure Partition(var A : arrayType; First, Last : Byte);
var
  Right,Left : byte ;
  V,Temp     : integer;
begin
    V := A[(First + Last) SHR 1];
    Right := First;
    Left := Last;
    repeat
      while (A[Right] < V) do
        inc(Right);
      while (A[Left] > V) do
        Dec(Left);
      if (Right <= Left) then
        begin
          Temp:=A[Left];
          A[Left]:=A[Right];
          A[Right]:=Temp;
          Right:=Right+1;
          Left:=Left-1;
        end;
    until Right > Left;
    if (First < Left) then
      Partition(A, First, Left);
    if (Right < Last) then
      Partition(A, Right, Last)
end;

{-----------------------------------------------------------------------------}
function BlackScan(var NextPoint:PointType) : boolean;
begin
  BlackScan:=true;
  repeat
    if NextPoint.X=Max_X_Width then
      begin
        if NextPoint.Y < Y_Width then
          begin
            NextPoint.X:=0 ;
            NextPoint.Y:=NextPoint.Y+1;
          end
        else
          begin
            BlackScan:=false;
            exit;
          end ; { IF }
      end ; { IF }
    NextPoint.X:=NextPoint.X+1;
  until GetPixel(NextPoint.X,NextPoint.Y)=0;
end ;

{------------------------------------------------------------------------------}
procedure Fill(Ymin,Ymax,LastColor:integer);
var
 P1,P3,P4,P    : integer ;
 Len,P2        : byte ;
 Darray        : arraytype;
begin
  SetColor(LastColor);
  for P1:=Ymin+1 to Ymax-1 do
   begin
     Len:=LineY[P1] ;
     if Len >= 2 then
      begin
        for P2:=1 to Len do
          Darray[P2]:=LineX[P2,P1] ;
        if Len > 2 then
          Partition(Darray,1,len);
        P2:=1;
        repeat
          P3:= Darray[P2] ; P4:= Darray[P2 + 1];
          if P3 <> P4 then
           begin
             line ( P3 , P1 , P4 , P1) ;
             if SymetricCase then
              begin
                P:=Max_Y_Width-P1;
                line ( P3 , P , P4 , P ) ;
              end;
           end; { IF }
          P2:=P2+2;
        until P2 >= Len ;
      end; { IF }
   end; { FOR }
end;

{-----------------------------------------------------------------------------}
Function NewPosition(Last:Byte):Byte;
begin
  newposition:=(((last+1) and 254)+6) and 7;
end;

{-----------------------------------------------------------------------------}
procedure CalcBounds;
var
  lastOperation,KK,
  Position                     : Byte ;
  foundcolor                   : longint;
  Start,Found,NotFound         : boolean ;
  MerkY,Ymax                   : Integer ;
label
  L;
begin
  repeat
    FillChar(LineY,SizeOf(LineY),0) ;
    ActualPoint:=NextPoint;
    LastColor:=CalcMandel(NextPoint,Zm) ;
    putpixel (ActualPoint.X,ActualPoint.Y,LastColor);
    if SymetricCase then
      putpixel (ActualPoint.X,Max_Y_Width-ActualPoint.Y,LastColor) ;
    Ymax:=NextPoint.Y ;
    MerkY:=NextPoint.Y ;
    NotFound:=false ;
    Start:=false ;
    LastOperation:=4 ;
    repeat
      Found:=false ;
      KK:=0 ;
      Position:=NewPosition(LastOperation);
      repeat
        LastOperation:=(Position+KK) and 7 ;
        SearchPoint.X:=ActualPoint.X+Sx[LastOperation];
        SearchPoint.Y:=ActualPoint.Y+Sy[LastOperation];
        if ((SearchPoint.X < 0) or
            (SearchPoint.X > Max_X_Width) or
            (SearchPoint.Y < NextPoint.Y) or
            (SearchPoint.Y > Y_Width)) then
          goto L;
        if (SearchPoint.X=NextPoint.X) and (SearchPoint.Y=NextPoint.Y) then
          begin
            Start:=true ;
            Found:=true ;
          end
        else
          begin
            FoundColor:=GetPixel(SearchPoint.X,SearchPoint.Y) ;
            if FoundColor = 0 then
              begin
                FoundColor:= CalcMandel (SearchPoint,Zm) ;
                Putpixel (SearchPoint.X,SearchPoint.Y,FoundColor) ;
                if SymetricCase then
                  PutPixel (SearchPoint.X,Max_Y_Width-SearchPoint.Y,FoundColor) ;
              end ;
            if ColorsEqual(FoundColor,LastColor) then
              begin
                if ActualPoint.Y <> SearchPoint.Y then
                  begin
                    if SearchPoint.Y = MerkY then
                      LineY[ActualPoint.Y]:=LineY[ActualPoint.Y]-1;
                    MerkY:= ActualPoint.Y ;
                    LineY[SearchPoint.Y]:=LineY[SearchPoint.Y]+1;
                  end ;
                LineX[LineY[SearchPoint.Y],SearchPoint.Y]:=SearchPoint.X ;
                if SearchPoint.Y > Ymax then Ymax:= SearchPoint.Y ;
                  Found:=true ;
                ActualPoint:=SearchPoint ;
              end;
L:
            KK:=KK+1;
            if KK > 8 then
              begin
                Start:=true ;
                NotFound:=true ;
              end;
          end;
      until Found or (KK > 8);
    until Start ;
    if not NotFound then
      Fill(NextPoint.Y,Ymax,LastColor) ;
  until not BlackScan(NextPoint);
end ;


{------------------------------------------------------------------------------
                              MAINROUTINE
------------------------------------------------------------------------------}
  var
     error : word;

var neededtime,starttime : longint;
  hour, minute, second, sec100 : word;
const
{$ifdef win32}
  gmdefault : word = m640x480x16;
{$else not win32}
  {$ifdef Linux}
   gmdefault : word = g640x480x256;
  {$else}
   gmdefault : word = m640x480x256;
  {$endif}
{$endif win32}

begin
  if paramcount>0 then
    begin
       val(paramstr(1),gm,error);
       if error<>0 then
         gm:=gmdefault;
    end
  else
    gm:=gmdefault;
  gd:=detect;
  GetTime(hour, minute, second, sec100);
  starttime:=((hour*60+minute)*60+second)*100+sec100;
  InitGraph(gd,gm,'');
  if GraphResult <> grOk then
    begin
      Writeln('Graph driver ',gd,' graph mode ',gm,' not supported');
      Halt(1);
    end;
  Max_X_Width:=GetMaxX;
  Max_y_Width:=GetMaxY;
  Max_Color:=GetMaxColor-1;
  ClearViewPort;

  x1:=-0.9;
  x2:= 2.2;
  y1:= 1.25;
  y2:=-1.25;
  zm:=90;
  dx:=(x1 - x2) / Max_X_Width ;
  dy:=(y1 - y2) / Max_Y_Width ;
  if abs(y1) = abs(y2) then
   begin
     SymetricCase:=true;
     Y_Width:=Max_Y_Width shr 1
   end
  else
   begin
     SymetricCase:=false;
     Y_Width:=Max_Y_Width;
   end;
  NextPoint.X:=0;
  NextPoint.Y:=0;
  LastColor:=CalcMandel(SearchPoint,zm);
  CalcBounds ;
  GetTime(hour, minute, second, sec100);
  neededtime:=((hour*60+minute)*60+second)*100+sec100-starttime;
{$ifndef fpc_profile}
  readln;
{$endif fpc_profile}
  CloseGraph;
  Writeln('Mandel took ',neededtime/100:0:3,' secs to generate mandel graph');
  Writeln('With graph driver ',gd,' and graph mode ',gm);
end.
{
  $Log$
  Revision 1.9  2000-02-22 03:43:55  alex
  fixed the warning

  Revision 1.8  2000/01/04 15:29:42  marco
   * fixed constants for graphmodes

  Revision 1.7  1999/12/22 14:36:07  jonas
    * changed type of max_color to word so it works now with 16bit color modes
      (thanks to Arjan van Dijk for noticing the problem)

  Revision 1.6  1999/12/14 22:59:52  pierre
   * adapted to new graph unit

  Revision 1.5  1999/05/27 21:36:33  peter
    * new demo's
    * fixed mandel for linux

  Revision 1.4  1998/12/20 22:22:10  peter
    * updates

}