% Uses:
% filter_at/5 - from file 'filter.p'
% Please:
% consult('../ch8/filter.p').
% consult('../util/math.p'). % \
% consult('../util/meta.p'). % \
% consult('../util/list.p'). % > - used by 'filter.p'
% consult('../ch8/image.p'). % /
% consult('../ch8/gimage.p'). % /
% The code for Life uses the image processing predicates
% developed for chapter 8
% The code is similar to that in the file 'threshold.p'
% except that it has a more complicated thresholding function
% (either 3 or 4 rather than over a given value) and also
% pre-filters each pixel using a 3x3 filter:
% [ [ 1, 1, 1 ],
% [ 1, 0, 1 ],
% [ 1, 1, 1 ] ]
% This filter effectively counts the population of the neighbouring cells
life_threshold( Pixel, 0 ) :- Pixel < 3, !.
life_threshold( Pixel, 0 ) :- Pixel > 4, !.
life_threshold( Pixel, 1 ).
life_at( Input, X, Y, Out_Pix ) :-
X1 is X-1, Y1 is Y-1,
filter_at( Input, [[1,1,1],[1,0,1],[1,1,1]], X1, Y1, In_Pix ),
life_threshold( In_Pix, Out_Pix ).
life_step( Input, Wid, Ht, Output ) :-
gimage_to_image( ( (X,Y,P), (Wid,Ht),
life_at(Input,X, Y, P) ),
Output ).
draw_life( [] ).
draw_life( [Col|Rest] ) :-
draw_life_col( Col ), nl,
draw_life( Rest ).
draw_life_col( Col ) :- write(Col).
run_life( Input, Wid, Ht, Nos_steps, Output ) :-
Nos_steps > 0, !,
draw_life( Input ), nl,
write('time left:'), write(Nos_steps), nl, nl,
life_step( Input, Wid, Ht, One_step ),
N1 is Nos_steps-1, !,
run_life( One_step, Wid, Ht, N1, Output ).
run_life( Input, _, _, Nos_steps, Input) :-
Nos_steps =< 0,
draw_life( Input ), nl,
write('finished!'), nl, nl.
% Initial state in figure 10.2
example_life( 'figure 10.2', [ [ 0, 0, 0, 0, 0 ],
[ 0, 0, 1, 1, 0 ],
[ 0, 1, 1, 1, 0 ],
[ 0, 1, 0, 0, 0 ],
[ 0, 0, 0, 0, 0 ] ] ).
