MODULE MandelbrotVoyager;

(*
My voyage on the complex plane.

To compile the source on the Oxford Compiler:
obc MandelbrotVoyager.mod -o MandelbrotVoyager

and to run the native code:
./MandelbrotVoyager


Program needs some refinement.
All the best Ty Harness.

ref: Dynamical Systems and Fractals - Karl-Heinz Becker and Michael Dorfler

*)

IMPORT  Out,XYplane;

(*Check your /usr/lib/obc/XYplane.m
has a screen widthxheight of 640x480 change accordingly*)

CONST H=480;
CONST W=640;

(*Complex Number*)
TYPE
Z = RECORD 
Re,i : REAL; 
END;

VAR
LLZ,URZ : Z;
dRe,di : REAL;
aspect : REAL;
Maxiter : INTEGER;
iter : INTEGER;
x,y,xx,yy,rr : REAL;
finished :BOOLEAN;
RetChar : CHAR;

PROCEDURE Init;
BEGIN
 iter := 0;
 finished := FALSE;
 x := 0;
 y := 0;
 xx := 0;
 yy := 0;
 rr := 0;
END Init;


PROCEDURE Draw():CHAR;
VAR
i,j : INTEGER;
c : Z;
a : CHAR;
BEGIN



  c := LLZ;

  FOR j := 0 TO H-1 DO
     FOR i := 0 TO W-1 DO 
      REPEAT
      Calc(c);
      test;
      UNTIL (iter = Maxiter) OR finished;
   
     (*Paint pixel black inside Mandlebrot Set*)
     IF (iter = Maxiter) THEN XYplane.Dot(i,j,XYplane.draw);END; 
  
  c.Re := c.Re + dRe;
  Init();

END;


  IF j < H-1 THEN c.Re := LLZ.Re;END;
  (*Dont reset the value at the end*)

  c.i := c.i + di;

END;


a := XYplane.Key();
RETURN(a);

END Draw;



PROCEDURE Zoomer(percentage:REAL);
BEGIN
LLZ.Re := LLZ.Re*percentage;
LLZ.i  := LLZ.i*percentage;
URZ.Re := URZ.Re*percentage;
URZ.i  := URZ.i*percentage;

(*Complex Number to Pixel transformation step size*)
dRe :=  (URZ.Re - LLZ.Re) / W;
di   := (URZ.i - LLZ.i) / H; 

Init;
XYplane.Clear();
END Zoomer;

PROCEDURE Pan(panRe,pani:REAL);
BEGIN
LLZ.Re := LLZ.Re + LLZ.Re*panRe*0.01;
LLZ.i  := LLZ.i  + LLZ.i*pani*0.01;
URZ.Re := URZ.Re - URZ.Re*panRe*0.01;
URZ.i  := URZ.i  - URZ.i*pani*0.01;
Init;
XYplane.Clear();
END Pan;


PROCEDURE Calc(C:Z);
BEGIN
(*
Square the starting number
add to constant (complex) number
to equal the new number to be squared.
*)

iter := iter +1;
y := x*y;
y := y + y - C.i;
x := xx - yy + C.Re;
xx := x*x;
yy := y*y;
rr := xx + yy;
END Calc;


PROCEDURE test;
BEGIN
 finished := (rr > 4);
END test;


PROCEDURE Writedestructions;
BEGIN
Out.String("Mandlebrot Set Zn+1 = Zn^2 + C");Out.Ln; 
Out.String("Press s to stop and close Xwindow");Out.Ln;
Out.String("Press i to see current parameters");Out.Ln;
Out.String("Press + to zoom in");Out.Ln;
Out.String("Press - to zoom out");Out.Ln;
Out.String("Press l to pan Real axis left");Out.Ln;
Out.String("Press r to pan Real axis right");Out.Ln;
Out.String("Press u to pan imaginery axis up");Out.Ln;
Out.String("Press d to pan imaginery axis down");Out.Ln;
Out.String("Press n to reduce number of iterations");Out.Ln;
Out.String("Press m to increase the number of iterations CAREFUL NOW");Out.Ln;Out.Ln;
END Writedestructions;


PROCEDURE WriteInfo;
BEGIN
Out.String("Boundries of current plot");Out.Ln;
Out.Real(LLZ.Re); Out.String(" + i("); Out.Real(LLZ.i); Out.String(")");
Out.Ln;
Out.Real(URZ.Re); Out.String(" + i("); Out.Real(URZ.i);Out.String(")");
Out.Ln;
Out.String("Max Iterations:"); Out.Int(Maxiter,0);
Out.Ln;
END  WriteInfo;




BEGIN (*Main*)

Writedestructions;

(*Aspect ratio for a non square XYplane W/H *)
aspect := W/H;

(*Set Inital Complex Plane Boundries*)
LLZ.Re := -2;
LLZ.i  := -aspect;
URZ.Re := 1;
URZ.i  := aspect;

(*Complex Number to Pixel transformation step size*)
dRe :=  (URZ.Re - LLZ.Re) / W;
di   := (URZ.i - LLZ.i) / H; 

Maxiter := 24;(*Sensible starting point for Raspberry Pi 2*)
Init;


XYplane.Open; 

REPEAT



RetChar := Draw();

IF RetChar = "+" THEN Zoomer(0.9); END;
IF RetChar = "-" THEN Zoomer(1.1); END;
IF RetChar = "l" THEN Pan(-10,0); END;
IF RetChar = "r" THEN Pan(10,0); END;
IF RetChar = "u" THEN Pan(0,10); END;
IF RetChar = "d" THEN Pan(0,-10); END;

IF RetChar = "m" THEN Maxiter := Maxiter +1; END;
IF RetChar = "n" THEN Maxiter := Maxiter -1; END;
IF Maxiter <= 1 THEN Maxiter := 1;END;
IF Maxiter >= 64 THEN Maxiter := 64;END;
IF (RetChar = "m") OR (RetChar = "n") THEN XYplane.Clear; END;
IF RetChar = "i" THEN  WriteInfo; END;

UNTIL "s" = RetChar;


Out.Ln;
Out.String("Finished - Bye");
Out.Ln;



END MandelbrotVoyager.