Turtle Graphics/Fractal Library SWI Prolog

%http://mundotecfacil.blogspot.com/
%SWI Prolog
turtle_init(Color):-
   retractall(turtle(_,_,_)),
   B is 600,
   H is 600,
   B1 is B /2,
   H1 is H / 2,
   W1 is 0,
   assert(turtle(B1, H1, W1)),
   free(@logo),
   new(@logo, picture('Fractals', size(B, H))),
   send(@logo, background(Color)),
   send(@logo, open_centered).

turtle_term:-
  retractall(logo/3),
  free(@logo).

turtle_drawto(X, Y):-
  retract(turtle(X1, Y1, W)),
  send(@logo, display, new(_, line(X1, Y1, X, Y))),
  assert(turtle(X, Y, W)).

turtle_drawRand(L):-
  retract(turtle(X1, Y1, W)),
  X2 is X1 + L*cos(W*pi/180),
  Y2 is Y1 - L*sin(W*pi/180),
  send(@logo, display, new(LINE, line(X1, Y1, X2, Y2))),
  random(1000, 65535, RAND1),
  random(1000, 65535, RAND2),
  random(1000, 65535, RAND3),
  new(C, colour(@default, RAND1, RAND2, RAND3)),
  send(LINE, colour, C),
  assert(turtle(X2, Y2, W)).

turtle_draw(L):-
  retract(turtle(X1, Y1, W)),
  X2 is X1 + L*cos(W*pi/180),
  Y2 is Y1 - L*sin(W*pi/180),
  send(@logo, display, new(LINE, line(X1, Y1, X2, Y2))),
  new(C, colour(@default, 0, 0, 0)),
  send(LINE, colour, C),
  assert(turtle(X2, Y2, W)).

turtle_moveto(X, Y):-
  retract(turtle(_, _, W)),
  assert(turtle(X, Y, W)).

turtle_drawRGB(L,Rojo,Verde,Azul):-
  retract(turtle(X1, Y1, W)),
  X2 is X1 + L*cos(W*pi/180),
  Y2 is Y1 - L*sin(W*pi/180),
  send(@logo, display, new(LINE, line(X1, Y1, X2, Y2))),
  new(C, colour(@default, Rojo, Verde, Azul)),
  send(LINE, colour, C),
  assert(turtle(X2, Y2, W)).

turtle_move(L):-
  retract(turtle(X1, Y1, W)),
  X2 is X1 + L*cos(W*pi/180),
  Y2 is Y1 - L*sin(W*pi/180),
  assert(turtle(X2, Y2, W)).

 turtle_turn(W):-
  retract(turtle(X, Y, W1)),
  W2 is W1 + W,
  assert(turtle(X, Y, W2)).

turtle_turnto(W):-
  retract(turtle(X, Y, _)),
  assert(turtle(X, Y, W)).

drCorbatin(0,Largo,Rojo,Verde,Azul):-
  turtle_drawRGB(Largo,Rojo,Verde,Azul).

drCorbatin(N,Largo,Rojo,Verde,Azul):-
  Seg is Largo / 4,
  N1 is N - 1,
  turtle_turn(60),
  drCorbatin(N1,Seg,Rojo,Verde,Azul),
  turtle_turn(-120),
  drCorbatin(N1,Seg,Rojo,Verde,Azul),
  drCorbatin(N1,Seg,Rojo,Verde,Azul),
  turtle_turn(120),
  drCorbatin(N1,Seg,Rojo,Verde,Azul),
  turtle_turn(-60).