Program draws mandala image

Category: KMP (Club of young programmers)
Author: Ján Benkovič
web: www.tbteacher.host.sk

Program: Mandel2.pas
File exe: Mandel2.exe

{ MANDEL2.PAS                                                       }
{ Program vykresli mandelov obrazec.                                }
{                                                                   }
{ Datum:04.10.1994                             http://www.trsek.com }
 
uses crt;
const XMax=160;  YMax=100;
var cc:char;
 
var X,Xbe,Y:integer;
    dim,dre,Yb,Ye,Xb,Xe:real;
var Z,Z1,C:record
          Re,Im:real;
        end;
    Krok:integer;
 
 
PROCEDURE Mandel;
var p,e:^byte;
begin
  dre:=(Xe-Xb)/XMax;
  dim:=(Ye-Yb)/YMax;
 
  p:=ptr($0a000,0);
  C.Im:=Yb;
  while C.Im>=Ye do
  begin
    e:=p;
    C.Re:=Xb;
    while C.Re<=Xe do
    begin
      Z.Re:=0;
      Z.Im:=0;
      Krok:=0;
      repeat
        Z1.Re:=Z.Re*Z.Re-Z.Im*Z.Im  +C.Re;        {Z[i+1]:=Z[i]*Z[i] + C}
        Z.Im:=2*Z.Re*Z.Im           +C.Im;
 
        Z.Re:=Z1.Re;
        inc(krok);
      until (krok>50) or (Abs(Z.Re*Z.Re+Z.Im*Z.Im)>4);
      p^:=15+krok mod 100;    inc(p);
      C.Re:=C.Re+dre;
    end;
    C.Im:=C.Im+dim;
    p:=e; inc(p,320);
  end;
end;
 
begin
  asm
    mov ax,0013h
    int 10h
  end;
  Y:=0; Xbe:=0;  Yb:=2;  Ye:=-2;  Xb:=-2;  Xe:=2;    Mandel;  cc:=readkey;
{  Y:=0; Xbe:=40;  Yb:=-0.5;  Ye:=-0.4;  Xb:=-0.35;  Xe:=0.15;    Mandel;  cc:=readkey;}
{  Xb:=0.2286305064;  Xe:=0.237024009;  Ye:=-0.553911055;  Yb:=-0.547616189;    Mandel;  cc:=readkey;}
{  Y:=0; Xbe:=0;  Ye:=-1.12;  Yb:=-0.84;  Xb:=-0.2375;  Xe:=0.0375;    Mandel;  cc:=readkey;}
 
end.