Turtle in Delphi

unit Unit1;

interface

uses
Windows, Messages, SysUtils, Variants, Classes, Graphics, Controls, Forms,
Dialogs, StdCtrls, ExtCtrls;

type
TForm1 = class(TForm)
PaintBox1: TPaintBox;
start: TButton;
Button2: TButton;
Edit1: TEdit;
Edit2: TEdit;
Panel1: TPanel;
GroupBox1: TGroupBox;
Label1: TLabel;
Label2: TLabel;
procedure Button2Click(Sender: TObject);
procedure startClick(Sender: TObject);
private
{ Private-Deklarationen }
public
{ Public-Deklarationen }
end;

Tturtle = class // unser Zeichengerät ^^
private
z: Tpaintbox;
posx, posy: real;
dir: real;
pen: boolean;
public
constructor create(pb:tpaintbox);
procedure SA;
procedure SH;
procedure VW(d:real);
procedure DL(d:real);
procedure DR(d:real);
procedure Links;
procedure rechts;
procedure mitte;
procedure oben;
procedure unten;
procedure setze(x,y,d:integer);
end ;

var
Form1: TForm1;
kurve: tturtle;

implementation

var
n: integer;
l,f: real;

{$R *.dfm}

function arcsin(x:real):real;
begin
arcsin:=arctan(x/sqrt(1-sqr(x)))
end;
function arccos(x:real):real;
begin
arccos:=arctan(sqrt(1-sqr(x))/x);
end;


procedure tturtle.mitte; //turtle kommt in die Mitte vom Bildschirm
begin
posx:=z.width div 2;
posy:=z.Height div 2;
dir:=90;
end;

procedure tturtle.links; //turtle an den linken Rand
begin
posx:=0;
posy:=z.Height div 2;
dir:=0;
end;

procedure tturtle.rechts; //siehe oben
begin
posx:=z.width;
posy:=z.Height div 2;
dir:=180;
end;

procedure tturtle.oben;
begin
posx:=z.width div 2;
posy:=0;
dir:=270;
end;

procedure tturtle.unten;
begin
posx:=z.width div 2;
posy:=z.Height;
dir:=90;
end;


constructor tturtle.create(pb:tpaintbox); //turtle wird erstellt
begin
z:=pb;
posx:=0; posy:=0; dir:=0;
pen:=true;
z.refresh;
end;

procedure tturtle.SA; //Anfang des Zeichnens
begin
if pen=false then
pen:=true;
end;

procedure tturtle.SH; //Ende des Zeichnens
begin
pen:=false;
end;

procedure tturtle.dl(d:real); //linksdrehung
begin
dir:=dir+d;
if dir > 360 then begin
while dir >360 do Dir:=dir-360;
end
else begin
while dir< 0 do dir:= dir+360;
end;
end;

procedure tturtle.dr(d:real); //rechtsdrehung
begin
DL(-d);
end;

procedure tturtle.vw(d:real); //vorwärtsgehen
begin
z.canvas.moveto(trunc(posx),trunc(posy));
posx:=posx+cos(dir/180*pi)*d;
posy:=posy-sin(dir/180*pi)*d;
if pen then z.canvas.lineto (trunc(posx),trunc(posy));
end;

procedure tturtle.setze(x,y,d:integer);
begin
posx:=x;
posy:=y;
dir:=d;
end;

procedure TForm1.Button2Click(Sender: TObject);
begin
close;
end;

procedure rek (n: integer ; l: real); //die prozedur zum zeichnen der äste
begin
if n=1
then
begin
kurve.SA;
kurve.DL(60);
kurve.VW(l);
kurve.SH;
kurve.VW(-l);
kurve.Dr(120);
kurve.SA;
kurve.VW(l);
kurve.SH;
kurve.VW(-l);
kurve.dl(60);
end

else
begin
kurve.SA;
kurve.DL(60);
kurve.VW(l);
rek(n-1 , l*0.6);
kurve.VW(-l);
kurve.Dr(120);
kurve.SA;
kurve.VW(l);
rek(n-1 , l*0.6);
kurve.VW(-l);
kurve.dl(60);
end;
end;

procedure TForm1.startClick(Sender: TObject); //das "hauptprogramm"
begin
n:=strtoint(edit1.Text);
l:=strtofloat(edit2.text);
kurve:=tturtle.create(paintbox1);
kurve.sa;
kurve.Mitte;
kurve.VW(1.6*l);
rek(n,l);
kurve.mitte;
kurve.Dr(120);
kurve.sa;
kurve.VW(1.6*l);
rek(n,l);
kurve.mitte;
kurve.dr(240);
kurve.SA;
kurve.VW(1.6*l);
rek(n,l);


end;

end.