{ *************************************************************

   Multi-Plane Star Scroller
   -------------------------


   In conjunction with :-


   M . T . S . I
   -------------

     Multi-Tasking Software Interrupts

         Developed and Written By

               Franz - Josef Ayestaran

                  1992

 ************************************************************** }


program StarScroller;

uses crt, graph;

Type  List  = array[1..50] of integer;
      List2 = array[1..50] of integer;
      List3 = array[1..50] of integer;
      List4 = array[1..50] of integer;

Const

   Gray50  : FillPatternType = ( $AA, $55, $AA, $55, $AA, $55, $AA, $55 );
   Leds    : FillPatternType = ( $AA, $00, $AA, $00, $AA, $00, $AA, $00 );

var   gd, gm, Count, Count2, Loop, Loop2,
     
      StarsScrollCount,  StarsScrollLoop,
      StarX, StarY, Timer, StarColor,
      StarsInterupt, StarsInteruptLength,
      StarsOn_Off
                   : integer;

        OldPattern : FillPatternType;

      StarsX       : List;
      StarsXBackup : List3;
      StarsY       : List2;
      StarsColor   : List3;
      Direction    : char;

{--------------------------------------------------------------}

              {   >>>>  P R O C E D U R E S <<<<   }

 Procedure InitGraphics;

 Var Gd, Gm : integer;

   begin
     Gd := Detect; InitGraph(Gd, Gm, '');
     if GraphResult <> grOK then Halt(1);
   end;

{---------------------------------------------------------------}

   Procedure BackGround;

    begin

     ClearViewPort;
     SetColor(9);
     Rectangle(1,1,GetMaxX,200);
     FloodFill(2,2,9);
    end;

{-----------------------------------------------------------------------}
{--  5 Plane Star Scroller Developed By Franz Ayestaran 23 October 92 --}
{-----------------------------------------------------------------------}

   Procedure InitStars;
    begin
     SetColor(White);

     Randomize;


     Loop := 0;

    Repeat

      StarX     := Random(GetMaxX);
      StarY     := Random(GetMaxY);

     Repeat

      StarColor := 15;

     Until StarColor > 0;

      StarsX[Loop]       := StarX;
      StarsXBackup[Loop] := StarX;
      StarsY[Loop]       := StarY;
      StarsColor[Loop]   := StarColor;

      Loop := Loop + 1;

     Until Loop > 49;
   end;
{===============================================================}

  Procedure ClearStars;
   begin
     Loop := 0;
     Repeat

      StarX := StarsX[Loop];
      StarY := StarsY[Loop];
      PutPixel(StarX,StarY,0);

      Loop := Loop + 1;

     Until Loop > 50;
   end;

{===============================================================}

                  {       M . T . S . I       }

              {   >>>>  P R O C E D U R E S <<<<   }

   Procedure ScrollStarsR2L;
    begin

    StarsInterupt := StarsInterupt + 1;
    If (StarsOn_Off = 1) and (StarsInterupt > StarsInteruptLength) then

    begin
     ClearStars;
     StarsInterupt   := 0;
     Timer           := 0;
     StarsScrollLoop := 0;

        {------------------------------------------------------------}
        {--- The Speed Of The 5 Scroll Planes Are Controlled Here ---}

     Repeat

      StarX := StarsX[StarsScrollLoop];

      If StarX <= 0 then StarX := GetMaxX;

      { --- Star PlayField 1 --- }

      If  (StarsScrollLoop >=  0) and
          (StarsScrollLoop <= 10) then  begin
                                         StarX := StarX - 1;   { <- speed }
                                        end;

      { --- Star PlayField 2 --- }

      If  (StarsScrollLoop >= 10) and
          (StarsScrollLoop <= 20) then  begin
                                         StarX := StarX - 2;
                                        end;

      { --- Star PlayField 3 --- }

      If  (StarsScrollLoop >= 20) and
          (StarsScrollLoop <= 30) then  begin
                                         StarX := StarX - 3;
                                        end;

      { --- Star PlayField 4 --- }

      If  (StarsScrollLoop >= 30) and
          (StarsScrollLoop <= 40) then  begin
                                         StarX := StarX - 4;
                                        end;

      { --- Star PlayField 5 --- }

      If  (StarsScrollLoop >= 40) and
          (StarsScrollLoop <= 50) then  begin
                                         StarX := StarX - 5;
                                        end;


      StarsX[StarsScrollLoop] := StarX;

      StarsScrollLoop := StarsScrollLoop + 1;

     Until StarsScrollLoop >= 51;

{===============================================================}

    Loop := 0;
     Repeat

      StarX     := StarsX[Loop];
      StarY     := StarsY[Loop];
      StarColor := StarsColor[Loop];
      PutPixel(StarX,StarY,StarColor);

      Loop := Loop + 1;

     Until Loop > 50;


                         end;
    end;

{---------------------------------------------------------------}
{---------------------------------------------------------------}
{---------------------------------------------------------------}

   Procedure ScrollStarsL2R;
    begin

    StarsInterupt := StarsInterupt + 1;
    If (StarsOn_Off = 1) and (StarsInterupt > StarsInteruptLength) then

    begin
     ClearStars;
     StarsInterupt   := 0;
     Timer           := 0;
     StarsScrollLoop := 0;

        {------------------------------------------------------------}
        {--- The Speed Of The 5 Scroll Planes Are Controlled Here ---}

     Repeat

      StarX := StarsX[StarsScrollLoop];

      If StarX >= GetMaxX then StarX := 0;

      { --- Star PlayField 1 --- }

      If  (StarsScrollLoop >=  0) and
          (StarsScrollLoop <= 10) then  begin
                                         StarX := StarX + 1;   { <- speed }
                                        end;

      { --- Star PlayField 2 --- }

      If  (StarsScrollLoop >= 10) and
          (StarsScrollLoop <= 20) then  begin
                                         StarX := StarX + 2;
                                        end;

      { --- Star PlayField 3 --- }

      If  (StarsScrollLoop >= 20) and
          (StarsScrollLoop <= 30) then  begin
                                         StarX := StarX + 3;
                                        end;

      { --- Star PlayField 4 --- }

      If  (StarsScrollLoop >= 30) and
          (StarsScrollLoop <= 40) then  begin
                                         StarX := StarX + 4;
                                        end;

      { --- Star PlayField 5 --- }

      If  (StarsScrollLoop >= 40) and
          (StarsScrollLoop <= 50) then  begin
                                         StarX := StarX + 5;
                                        end;


      StarsX[StarsScrollLoop] := StarX;

      StarsScrollLoop := StarsScrollLoop + 1;

     Until StarsScrollLoop >= 51;

{===============================================================}

    Loop := 0;
     Repeat

      StarX     := StarsX[Loop];
      StarY     := StarsY[Loop];
      StarColor := StarsColor[Loop];
      PutPixel(StarX,StarY,StarColor);

      Loop := Loop + 1;

     Until Loop > 50;


                         end;
    end;

{---------------------------------------------------------------}
{---------------------------------------------------------------}
{---------------------------------------------------------------}

   Procedure ScrollStarsT2B;
    begin

    StarsInteruptLength := 300;
    StarsInterupt := StarsInterupt + 1;
    If (StarsOn_Off = 1) and (StarsInterupt > StarsInteruptLength) then

    begin
     ClearStars;
     StarsInterupt   := 0;
     Timer           := 0;
     StarsScrollLoop := 0;

        {------------------------------------------------------------}
        {--- The Speed Of The 5 Scroll Planes Are Controlled Here ---}

     Repeat

      StarY := StarsY[StarsScrollLoop];

      If StarY >= GetMaxY then StarY := 0;

      { --- Star PlayField 1 --- }

      If  (StarsScrollLoop >=  0) and
          (StarsScrollLoop <= 10) then  begin
                                         StarY := StarY + 1;   { <- speed }
                                        end;

      { --- Star PlayField 2 --- }

      If  (StarsScrollLoop >= 10) and
          (StarsScrollLoop <= 20) then  begin
                                         StarY := StarY + 2;
                                        end;

      { --- Star PlayField 3 --- }

      If  (StarsScrollLoop >= 20) and
          (StarsScrollLoop <= 30) then  begin
                                         StarY := StarY + 3;
                                        end;

      { --- Star PlayField 4 --- }

      If  (StarsScrollLoop >= 30) and
          (StarsScrollLoop <= 40) then  begin
                                         StarY := StarY + 4;
                                        end;

      { --- Star PlayField 5 --- }

      If  (StarsScrollLoop >= 40) and
          (StarsScrollLoop <= 50) then  begin
                                         StarY := StarY + 5;
                                        end;


      StarsY[StarsScrollLoop] := StarY;

      StarsScrollLoop := StarsScrollLoop + 1;

     Until StarsScrollLoop >= 51;

{===============================================================}

     Loop := 0;
     Repeat

      StarX     := StarsX[Loop];
      StarY     := StarsY[Loop];
      StarColor := StarsColor[Loop];
      PutPixel(StarX,StarY,StarColor);

      Loop := Loop + 1;

     Until Loop > 50;


                         end;
    end;

{---------------------------------------------------------------}
{---------------------------------------------------------------}
{---------------------------------------------------------------}

   Procedure ScrollStarsB2T;
    begin

    StarsInteruptLength := 300;
    StarsInterupt := StarsInterupt + 1;
    If (StarsOn_Off = 1) and (StarsInterupt > StarsInteruptLength) then

    begin
     ClearStars;
     StarsInterupt   := 0;
     Timer           := 0;
     StarsScrollLoop := 0;

        {------------------------------------------------------------}
        {--- The Speed Of The 5 Scroll Planes Are Controlled Here ---}

     Repeat

      StarY := StarsY[StarsScrollLoop];

      If StarY <= 0 then StarY := GetMaxY;

      { --- Star PlayField 1 --- }

      If  (StarsScrollLoop >=  0) and
          (StarsScrollLoop <= 10) then  begin
                                         StarY := StarY - 1;   { <- speed }
                                        end;

      { --- Star PlayField 2 --- }

      If  (StarsScrollLoop >= 10) and
          (StarsScrollLoop <= 20) then  begin
                                         StarY := StarY - 2;
                                        end;

      { --- Star PlayField 3 --- }

      If  (StarsScrollLoop >= 20) and
          (StarsScrollLoop <= 30) then  begin
                                         StarY := StarY - 3;
                                        end;

      { --- Star PlayField 4 --- }

      If  (StarsScrollLoop >= 30) and
          (StarsScrollLoop <= 40) then  begin
                                         StarY := StarY - 4;
                                        end;

      { --- Star PlayField 5 --- }

      If  (StarsScrollLoop >= 40) and
          (StarsScrollLoop <= 50) then  begin
                                         StarY := StarY - 5;
                                        end;


      StarsY[StarsScrollLoop] := StarY;

      StarsScrollLoop := StarsScrollLoop + 1;

     Until StarsScrollLoop >= 51;

{===============================================================}

     Loop := 0;
     Repeat

      StarX     := StarsX[Loop];
      StarY     := StarsY[Loop];
      StarColor := StarsColor[Loop];
      PutPixel(StarX,StarY,StarColor);

      Loop := Loop + 1;

     Until Loop > 50;


                         end;
    end;

{===============================================================}

 Procedure Demo_1;

   Begin

     Initgraphics;
     InitStars;

     ClearViewPort;

     StarsInterupt       := 1;
     StarsInteruptLength := 250;
     StarsOn_Off         := 1;


                   {------------------------------------}
                   {----- Multi-Tasking Processing -----}

    Repeat

      {-- Multi Task 1 --}

      ScrollStarsR2L;

      {------------------}


    Until KeyPressed;

    closegraph;

  end;
{---------------------------------------------------------------}

     {   >>>>  E N D   O F   P R O C E D U R E S  <<<<   }

{ Main }

begin

 demo_1;

end.