40 lines
1.1 KiB
Prolog
40 lines
1.1 KiB
Prolog
:- dynamic top/1.
|
|
|
|
sierpinski_iterate(N) :-
|
|
retractall(top(_)),
|
|
sformat(A, 'Sierpinski order ~w', [N]),
|
|
new(D, picture(A)),
|
|
draw_Sierpinski_iterate(D, N, point(550, 50)),
|
|
send(D, open).
|
|
|
|
draw_Sierpinski_iterate(Window, N, point(X,Y)) :-
|
|
assert(top([point(X,Y)])),
|
|
NbTours is 2 ** (N - 1),
|
|
% Size is given here to preserve the "small" triangles when N is big
|
|
Len is 10,
|
|
forall(between(1, NbTours, _I),
|
|
( retract(top(Lst)),
|
|
assert(top([])),
|
|
forall(member(P, Lst),
|
|
draw_Sierpinski(Window, P, Len)))).
|
|
|
|
draw_Sierpinski(Window, point(X, Y), Len) :-
|
|
X1 is X - round(Len/2),
|
|
X2 is X + round(Len/2),
|
|
Y1 is Y + round(Len * sqrt(3) / 2),
|
|
send(Window, display, new(Pa, path)),
|
|
(
|
|
send(Pa, append, point(X, Y)),
|
|
send(Pa, append, point(X1, Y1)),
|
|
send(Pa, append, point(X2, Y1)),
|
|
send(Pa, closed, @on),
|
|
send(Pa, fill_pattern, colour(@default, 0, 0, 0))
|
|
),
|
|
retract(top(Lst)),
|
|
( member(point(X1, Y1), Lst) -> select(point(X1,Y1), Lst, Lst1)
|
|
; Lst1 = [point(X1, Y1)|Lst]),
|
|
|
|
( member(point(X2, Y1), Lst1) -> select(point(X2,Y1), Lst1, Lst2)
|
|
; Lst2 = [point(X2, Y1)|Lst1]),
|
|
|
|
assert(top(Lst2)).
|