RosettaCodeData/Task/Fractal-tree/Prolog/fractal-tree.pro

20 lines
505 B
Prolog

fractal :-
new(D, window('Fractal')),
send(D, size, size(800, 600)),
drawTree(D, 400, 500, -90, 9),
send(D, open).
drawTree(_D, _X, _Y, _Angle, 0).
drawTree(D, X1, Y1, Angle, Depth) :-
X2 is X1 + cos(Angle * pi / 180.0) * Depth * 10.0,
Y2 is Y1 + sin(Angle * pi / 180.0) * Depth * 10.0,
new(Line, line(X1, Y1, X2, Y2, none)),
send(D, display, Line),
A1 is Angle - 30,
A2 is Angle + 30,
De is Depth - 1,
drawTree(D, X2, Y2, A1, De),
drawTree(D, X2, Y2, A2, De).