Tile Map Generator

Draw a 10x10 map with a tendency to have a lake in the center:

Height=10,Width=10,mc_sample_arg_first(map(Height,Width,M),1,M,[ Map- _ ]).
:- use_module(library(mcintyre)). :- if(current_predicate(use_rendering/1)). :- use_rendering(tiles). :- endif. :-mc. :-begin_lpad. map(H,W,M):- tiles(Tiles), length(Rows,H), M=..[map,Tiles|Rows], foldl(select(H,W),Rows,1,_). select(H,W,Row,N0,N):- length(RowL,W), N is N0+1, Row=..[row|RowL], foldl(pick_row(H,W,N0),RowL,1,_). pick_row(H,W,N,T,M0,M):- M is M0+1, pick_tile(N,M0,H,W,T). % constraints on map generation % the center tile is water pick_tile(HC,WC,H,W,water):- HC is H//2, WC is W//2,!. % in the central area water is more probable (there tend to be a lake in the % center) pick_tile(Y,X,H,W,T):discrete(T,[grass:0.05,water:0.9,tree:0.025,rock:0.025]):- central_area(Y,X,H,W),!. % on the other places tiles are chosen at random with this distribution pick_tile(_,_,_,_,T):discrete(T,[grass:0.5,water:0.3,tree:0.1,rock:0.1]). :-end_lpad. central_area(Y,X,H,W):- HC is H//2, WC is W//2, adjacent(HC,WC,Y1,X1,H,W), adjacent(Y1,X1,Y,X,H,W). adjacent(Y,X,Y1,X1,H,W):- Y >= 1, Y =< H, X >= 1, X =< W, side(Y,X,Y1,X1,H,W). adjacent(Y,X,Y1,X1,H,W):- Y >= 1, Y =< H, X >= 1, X =< W, corner(Y,X,Y1,X1,H,W). side(Y,X,Y1,X1,H,W):- left(Y,X,Y1,X1,H,W). side(Y,X,Y1,X1,H,W):- right(Y,X,Y1,X1,H,W). side(Y,X,Y1,X1,H,W):- above(Y,X,Y1,X1,H,W). side(Y,X,Y1,X1,H,W):- below(Y,X,Y1,X1,H,W). % upper left corner corner(Y,X,Y1,X1,H,W):- left(Y1,X,Y1,X1,H,W), above(Y,X1,Y1,X1,H,W). % upper right corner corner(Y,X,Y1,X1,H,W):- right(Y1,X,Y1,X1,H,W), above(Y,X1,Y1,X1,H,W). % lower left corner corner(Y,X,Y1,X1,H,W):- left(Y1,X,Y1,X1,H,W), below(Y,X1,Y1,X1,H,W). % lower right corner corner(Y,X,Y1,X1,H,W):- right(Y1,X,Y1,X1,H,W), below(Y,X1,Y1,X1,H,W). left(Y,X,Y,X1,_,_):- X > 1, X1 is X-1. right(Y,X,Y,X1,_,W):- X < W, X1 is X+1. above(Y,X,Y1,X,_,_):- Y > 1, Y1 is Y-1. below(Y,X,Y1,X,H,_):- Y < H, Y1 is Y+1. tile_names(T):- findall(Tile,tile(Tile,_URL),T). tiles(T):- findall(tile(Tile,URL),tile(Tile,URL),T). % available tiles % format: tile(name,URL) % tiles from https://github.com/silveira/openpixels tile(grass,'http://cplint.lamping.unife.it/icons/tiles/grass.png'). tile(water,'http://cplint.lamping.unife.it//icons/tiles/water.png'). tile(rock,'http://cplint.lamping.unife.it//icons/tiles/rock.png'). tile(tree,'http://cplint.lamping.unife.it//icons/tiles/tree.png').