%% ------------------------------------------------- BOUNCE


toy :-  static([green, red, move, stop, start,quit]),
	*move:=1,*quit:=0,*stop:=0,*start:=1,*red:=0,*green:=1,
        bounce_init(W,R,G),@toy1(W,R,G).

toy1(W,R,G) :- 
	[](event),					% input
	s1,						% automaton
	[]((button_red(R),button_green(G),bounce(W))).  % output

% ?- compile(['../tableau/gi.out']).

event :- nextevent(E),E=E1,event_select(E1).
event_select(noevent) :- true.
event_select(button(_,start)) :- *start := 1, *stop  := 0.
event_select(button(_,stop)) :-  *stop  := 1, *start := 0.
event_select(button(_,quit)) :-  *quit := 1.

button_red(Out) :-
        *red =0, Out => out("").
button_red(Out) :-
        *red =1, Out => out("Red").
button_green(Out) :-
        *green =0, Out => out("").
button_green(Out) :-
        *green =1, Out => out("Green").

% size(400,400,10,fixed) :- true.
size(200,200,5,'7x14') :- true.

bounce_init( [Window0, View0, Circ0, Xout0, X, Yout0, 
        Y, Xd, Yd, Ydd, Xlim, Ylim],Xout0,Yout0) :-
        size(Hight,Width,R,Font),
	H0 = Hight-2, W0 = Width-2,
	H1 = Hight/2, W1 = Width/2,
	View <= view(Hight,Width),
%        View => setcolors(rgb(65000,0,0),white),
	Xout <= output("Red",font(Font)),
	Yout <= output("Green",font(Font)),
	Start <= button("Start",start,font(Font)),
	Stop <= button("Stop",stop,font(Font)),
	Quit <= button("Quit",quit,font(Font)),
	Box <= hbox([vbox([Xout,Yout,space,Start,Stop,Quit]),View]),
	Window <= window("Toy Program",Box),
	Window => open,
	View => rect(0,0,H0,W0),
        View => fillcircle(Circ,H1,W1,R),	
	Window0<--Window, View0<--View, Circ0<--Circ, 
	Xout0<--Xout,  Yout0<--Yout,
	Ylim = Hight-10, Xlim = Width-10, Ydd = -R/2,
	#((@Ylim=Ylim,@Xlim=Xlim,@Ydd=Ydd)),
	@X = H1, @Y = W1, @Xd = R/2, @Yd = R*2.
bounce([_, View, Obj, _Xout, X, _Yout, Y, Xd, Yd, Ydd, Xlim, _]) :- 
	*move = 1,*quit = 0,
	X0 is integer(X), Y0 is integer(Y),
	View => moveto(Obj,X0,Y0),	
	Y1 is Y+Yd,
	calc_xd(X, Xd, Xd1, Xlim),
	calc_yd(Y, Yd, Ydt, Y1, Yt1),
	@X = X+Xd,@Xd = Xd1, @Y = Yt1, @Yd = Ydt+Ydd.
bounce([_, _, _, _, X, _, Y, Xd, Yd, _, _, _]) :- 
	*move = 0,*quit = 0,
	@X = X,@Xd = Xd, @Y = Y, @Yd = Yd.
bounce([W|_]) :-
	*quit = 1,
	W => close.

calc_xd(X, Xd, Xd1, _) :- X < 10,  Xd1 is abs(Xd).
calc_xd(X, Xd, Xd1, Xlim) :- X > Xlim,  Xd1 is -abs(Xd).
calc_xd(_, Xd, Xd, _):-true.

calc_yd(Y, Yd, Ydt, _, Y0) :-
	Y < 10,  Yd > 0 , Ydt = Yd,Y0 = 10.
calc_yd(Y, Yd, Ydt, _, Y0) :-
	Y < 10, Ydt = -Yd*0.9,Y0 = 10.
calc_yd(_, Yd, Yd, Y1, Y1):-true.