2 * slant.c: Puzzle from nikoli.co.jp involving drawing a diagonal
3 * line through each square of a grid.
7 * In this puzzle you have a grid of squares, each of which must
8 * contain a diagonal line; you also have clue numbers placed at
9 * _points_ of that grid, which means there's a (w+1) x (h+1) array
10 * of possible clue positions.
12 * I'm therefore going to adopt a rigid convention throughout this
13 * source file of using w and h for the dimensions of the grid of
14 * squares, and W and H for the dimensions of the grid of points.
15 * Thus, W == w+1 and H == h+1 always.
17 * Clue arrays will be W*H `signed char's, and the clue at each
18 * point will be a number from 0 to 4, or -1 if there's no clue.
20 * Solution arrays will be W*H `signed char's, and the number at
21 * each point will be +1 for a forward slash (/), -1 for a
22 * backslash (\), and 0 for unknown.
45 * In standalone solver mode, `verbose' is a variable which can be
46 * set by command-line option; in debugging mode it's simply always
49 #if defined STANDALONE_SOLVER
50 #define SOLVER_DIAGNOSTICS
52 #elif defined SOLVER_DIAGNOSTICS
57 * Difficulty levels. I do some macro ickery here to ensure that my
58 * enum and the various forms of my name list always match up.
63 #define ENUM(upper,title,lower) DIFF_ ## upper,
64 #define TITLE(upper,title,lower) #title,
65 #define ENCODE(upper,title,lower) #lower
66 #define CONFIG(upper,title,lower) ":" #title
67 enum { DIFFLIST(ENUM
) DIFFCOUNT
};
68 static char const *const slant_diffnames
[] = { DIFFLIST(TITLE
) };
69 static char const slant_diffchars
[] = DIFFLIST(ENCODE
);
70 #define DIFFCONFIG DIFFLIST(CONFIG)
76 typedef struct game_clues
{
90 unsigned char *errors
;
92 int used_solve
; /* used to suppress completion flash */
95 static game_params
*default_params(void)
97 game_params
*ret
= snew(game_params
);
100 ret
->diff
= DIFF_EASY
;
105 static const struct game_params slant_presets
[] = {
114 static int game_fetch_preset(int i
, char **name
, game_params
**params
)
119 if (i
< 0 || i
>= lenof(slant_presets
))
122 ret
= snew(game_params
);
123 *ret
= slant_presets
[i
];
125 sprintf(str
, "%dx%d %s", ret
->w
, ret
->h
, slant_diffnames
[ret
->diff
]);
132 static void free_params(game_params
*params
)
137 static game_params
*dup_params(game_params
*params
)
139 game_params
*ret
= snew(game_params
);
140 *ret
= *params
; /* structure copy */
144 static void decode_params(game_params
*ret
, char const *string
)
146 ret
->w
= ret
->h
= atoi(string
);
147 while (*string
&& isdigit((unsigned char)*string
)) string
++;
148 if (*string
== 'x') {
150 ret
->h
= atoi(string
);
151 while (*string
&& isdigit((unsigned char)*string
)) string
++;
153 if (*string
== 'd') {
156 for (i
= 0; i
< DIFFCOUNT
; i
++)
157 if (*string
== slant_diffchars
[i
])
159 if (*string
) string
++;
163 static char *encode_params(game_params
*params
, int full
)
167 sprintf(data
, "%dx%d", params
->w
, params
->h
);
169 sprintf(data
+ strlen(data
), "d%c", slant_diffchars
[params
->diff
]);
174 static config_item
*game_configure(game_params
*params
)
179 ret
= snewn(4, config_item
);
181 ret
[0].name
= "Width";
182 ret
[0].type
= C_STRING
;
183 sprintf(buf
, "%d", params
->w
);
184 ret
[0].sval
= dupstr(buf
);
187 ret
[1].name
= "Height";
188 ret
[1].type
= C_STRING
;
189 sprintf(buf
, "%d", params
->h
);
190 ret
[1].sval
= dupstr(buf
);
193 ret
[2].name
= "Difficulty";
194 ret
[2].type
= C_CHOICES
;
195 ret
[2].sval
= DIFFCONFIG
;
196 ret
[2].ival
= params
->diff
;
206 static game_params
*custom_params(config_item
*cfg
)
208 game_params
*ret
= snew(game_params
);
210 ret
->w
= atoi(cfg
[0].sval
);
211 ret
->h
= atoi(cfg
[1].sval
);
212 ret
->diff
= cfg
[2].ival
;
217 static char *validate_params(game_params
*params
, int full
)
220 * (At least at the time of writing this comment) The grid
221 * generator is actually capable of handling even zero grid
222 * dimensions without crashing. Puzzles with a zero-area grid
223 * are a bit boring, though, because they're already solved :-)
224 * And puzzles with a dimension of 1 can't be made Hard, which
225 * means the simplest thing is to forbid them altogether.
228 if (params
->w
< 2 || params
->h
< 2)
229 return "Width and height must both be at least two";
235 * Scratch space for solver.
237 struct solver_scratch
{
239 * Disjoint set forest which tracks the connected sets of
245 * Counts the number of possible exits from each connected set
246 * of points. (That is, the number of possible _simultaneous_
247 * exits: an unconnected point labelled 2 has an exit count of
248 * 2 even if all four possible edges are still under
254 * Tracks whether each connected set of points includes a
257 unsigned char *border
;
260 * Another disjoint set forest. This one tracks _squares_ which
261 * are known to slant in the same direction.
266 * Stores slash values which we know for an equivalence class.
267 * When we fill in a square, we set slashval[canonify(x)] to
268 * the same value as soln[x], so that we can then spot other
269 * squares equivalent to it and fill them in immediately via
270 * their known equivalence.
272 signed char *slashval
;
275 * Useful to have this information automatically passed to
276 * solver subroutines. (This pointer is not dynamically
277 * allocated by new_scratch and free_scratch.)
279 const signed char *clues
;
282 static struct solver_scratch
*new_scratch(int w
, int h
)
284 int W
= w
+1, H
= h
+1;
285 struct solver_scratch
*ret
= snew(struct solver_scratch
);
286 ret
->connected
= snewn(W
*H
, int);
287 ret
->exits
= snewn(W
*H
, int);
288 ret
->border
= snewn(W
*H
, unsigned char);
289 ret
->equiv
= snewn(w
*h
, int);
290 ret
->slashval
= snewn(w
*h
, signed char);
294 static void free_scratch(struct solver_scratch
*sc
)
300 sfree(sc
->connected
);
305 * Wrapper on dsf_merge() which updates the `exits' and `border'
308 static void merge_vertices(int *connected
,
309 struct solver_scratch
*sc
, int i
, int j
)
311 int exits
= -1, border
= FALSE
; /* initialise to placate optimiser */
314 i
= dsf_canonify(connected
, i
);
315 j
= dsf_canonify(connected
, j
);
318 * We have used one possible exit from each of the two
319 * classes. Thus, the viable exit count of the new class is
320 * the sum of the old exit counts minus two.
322 exits
= sc
->exits
[i
] + sc
->exits
[j
] - 2;
324 border
= sc
->border
[i
] || sc
->border
[j
];
327 dsf_merge(connected
, i
, j
);
330 i
= dsf_canonify(connected
, i
);
331 sc
->exits
[i
] = exits
;
332 sc
->border
[i
] = border
;
337 * Called when we have just blocked one way out of a particular
338 * point. If that point is a non-clue point (thus has a variable
339 * number of exits), we have therefore decreased its potential exit
340 * count, so we must decrement the exit count for the group as a
343 static void decr_exits(struct solver_scratch
*sc
, int i
)
345 if (sc
->clues
[i
] < 0) {
346 i
= dsf_canonify(sc
->connected
, i
);
351 static void fill_square(int w
, int h
, int x
, int y
, int v
,
353 int *connected
, struct solver_scratch
*sc
)
355 int W
= w
+1 /*, H = h+1 */;
357 assert(x
>= 0 && x
< w
&& y
>= 0 && y
< h
);
359 if (soln
[y
*w
+x
] != 0) {
360 return; /* do nothing */
363 #ifdef SOLVER_DIAGNOSTICS
365 printf(" placing %c in %d,%d\n", v
== -1 ?
'\\' : '/', x
, y
);
371 int c
= dsf_canonify(sc
->equiv
, y
*w
+x
);
376 merge_vertices(connected
, sc
, y
*W
+x
, (y
+1)*W
+(x
+1));
378 decr_exits(sc
, y
*W
+(x
+1));
379 decr_exits(sc
, (y
+1)*W
+x
);
382 merge_vertices(connected
, sc
, y
*W
+(x
+1), (y
+1)*W
+x
);
384 decr_exits(sc
, y
*W
+x
);
385 decr_exits(sc
, (y
+1)*W
+(x
+1));
391 * Solver. Returns 0 for impossibility, 1 for success, 2 for
392 * ambiguity or failure to converge.
394 static int slant_solve(int w
, int h
, const signed char *clues
,
395 signed char *soln
, struct solver_scratch
*sc
,
398 int W
= w
+1, H
= h
+1;
405 memset(soln
, 0, w
*h
);
410 * Establish a disjoint set forest for tracking connectedness
411 * between grid points.
413 for (i
= 0; i
< W
*H
; i
++)
414 sc
->connected
[i
] = i
; /* initially all distinct */
417 * Establish a disjoint set forest for tracking which squares
418 * are known to slant in the same direction.
420 for (i
= 0; i
< w
*h
; i
++)
421 sc
->equiv
[i
] = i
; /* initially all distinct */
424 * Clear the slashval array.
426 memset(sc
->slashval
, 0, w
*h
);
429 * Initialise the `exits' and `border' arrays. Theses is used
430 * to do second-order loop avoidance: the dual of the no loops
431 * constraint is that every point must be somehow connected to
432 * the border of the grid (otherwise there would be a solid
433 * loop around it which prevented this).
435 * I define a `dead end' to be a connected group of points
436 * which contains no border point, and which can form at most
437 * one new connection outside itself. Then I forbid placing an
438 * edge so that it connects together two dead-end groups, since
439 * this would yield a non-border-connected isolated subgraph
440 * with no further scope to extend it.
442 for (y
= 0; y
< H
; y
++)
443 for (x
= 0; x
< W
; x
++) {
444 if (y
== 0 || y
== H
-1 || x
== 0 || x
== W
-1)
445 sc
->border
[y
*W
+x
] = TRUE
;
447 sc
->border
[y
*W
+x
] = FALSE
;
449 if (clues
[y
*W
+x
] < 0)
450 sc
->exits
[y
*W
+x
] = 4;
452 sc
->exits
[y
*W
+x
] = clues
[y
*W
+x
];
456 * Make a one-off preliminary pass over the grid looking for
457 * starting-point arrangements. The ones we need to spot are:
459 * - two adjacent 1s in the centre of the grid imply that each
460 * one's single line points towards the other. (If either 1
461 * were connected on the far side, the two squares shared
462 * between the 1s would both link to the other 1 as a
463 * consequence of neither linking to the first.) Thus, we
464 * can fill in the four squares around them.
466 * - dually, two adjacent 3s imply that each one's _non_-line
467 * points towards the other.
469 * - if the pair of 1s and 3s is not _adjacent_ but is
470 * separated by one or more 2s, the reasoning still applies.
472 * This is more advanced than just spotting obvious starting
473 * squares such as central 4s and edge 2s, so we disable it on
476 * (I don't like this loop; it feels grubby to me. My
477 * mathematical intuition feels there ought to be some more
478 * general deductive form which contains this loop as a special
479 * case, but I can't bring it to mind right now.)
481 if (difficulty
> DIFF_EASY
) {
482 for (y
= 1; y
+1 < H
; y
++)
483 for (x
= 1; x
+1 < W
; x
++) {
484 int v
= clues
[y
*W
+x
], s
, x2
, y2
, dx
, dy
;
485 if (v
!= 1 && v
!= 3)
487 /* Slash value of the square up and left of (x,y). */
488 s
= (v
== 1 ?
+1 : -1);
490 /* Look in each direction once. */
491 for (dy
= 0; dy
< 2; dy
++) {
495 if (x2
+1 >= W
|| y2
+1 >= H
)
496 continue; /* too close to the border */
497 while (x2
+dx
+1 < W
&& y2
+dy
+1 < H
&& clues
[y2
*W
+x2
] == 2)
499 if (clues
[y2
*W
+x2
] == v
) {
500 #ifdef SOLVER_DIAGNOSTICS
502 printf("found adjacent %ds at %d,%d and %d,%d\n",
505 fill_square(w
, h
, x
-1, y
-1, s
, soln
,
507 fill_square(w
, h
, x
-1+dy
, y
-1+dx
, -s
, soln
,
509 fill_square(w
, h
, x2
, y2
, s
, soln
,
511 fill_square(w
, h
, x2
-dy
, y2
-dx
, -s
, soln
,
519 * Repeatedly try to deduce something until we can't.
522 done_something
= FALSE
;
525 * Any clue point with the number of remaining lines equal
526 * to zero or to the number of remaining undecided
527 * neighbouring squares can be filled in completely.
529 for (y
= 0; y
< H
; y
++)
530 for (x
= 0; x
< W
; x
++) {
535 int nu
, nl
, c
, s
, eq
, eq2
, last
, meq
, mj1
, mj2
;
537 if ((c
= clues
[y
*W
+x
]) < 0)
541 * We have a clue point. Start by listing its
542 * neighbouring squares, in order around the point,
543 * together with the type of slash that would be
544 * required in that square to connect to the point.
547 if (x
> 0 && y
> 0) {
548 neighbours
[nneighbours
].pos
= (y
-1)*w
+(x
-1);
549 neighbours
[nneighbours
].slash
= -1;
552 if (x
> 0 && y
< h
) {
553 neighbours
[nneighbours
].pos
= y
*w
+(x
-1);
554 neighbours
[nneighbours
].slash
= +1;
557 if (x
< w
&& y
< h
) {
558 neighbours
[nneighbours
].pos
= y
*w
+x
;
559 neighbours
[nneighbours
].slash
= -1;
562 if (x
< w
&& y
> 0) {
563 neighbours
[nneighbours
].pos
= (y
-1)*w
+x
;
564 neighbours
[nneighbours
].slash
= +1;
569 * Count up the number of undecided neighbours, and
570 * also the number of lines already present.
572 * If we're not on DIFF_EASY, then in this loop we
573 * also track whether we've seen two adjacent empty
574 * squares belonging to the same equivalence class
575 * (meaning they have the same type of slash). If
576 * so, we count them jointly as one line.
580 last
= neighbours
[nneighbours
-1].pos
;
582 eq
= dsf_canonify(sc
->equiv
, last
);
585 meq
= mj1
= mj2
= -1;
586 for (i
= 0; i
< nneighbours
; i
++) {
587 j
= neighbours
[i
].pos
;
588 s
= neighbours
[i
].slash
;
590 nu
++; /* undecided */
591 if (meq
< 0 && difficulty
> DIFF_EASY
) {
592 eq2
= dsf_canonify(sc
->equiv
, j
);
593 if (eq
== eq2
&& last
!= j
) {
595 * We've found an equivalent pair.
596 * Mark it. This also inhibits any
597 * further equivalence tracking
598 * around this square, since we can
599 * only handle one pair (and in
600 * particular we want to avoid
601 * being misled by two overlapping
602 * equivalence pairs).
607 nl
--; /* count one line */
608 nu
-= 2; /* and lose two undecideds */
615 nl
--; /* here's a line */
623 if (nl
< 0 || nl
> nu
) {
625 * No consistent value for this at all!
627 #ifdef SOLVER_DIAGNOSTICS
629 printf("need %d / %d lines around clue point at %d,%d!\n",
632 return 0; /* impossible */
635 if (nu
> 0 && (nl
== 0 || nl
== nu
)) {
636 #ifdef SOLVER_DIAGNOSTICS
639 printf("partially (since %d,%d == %d,%d) ",
640 mj1
%w
, mj1
/w
, mj2
%w
, mj2
/w
);
641 printf("%s around clue point at %d,%d\n",
642 nl ?
"filling" : "emptying", x
, y
);
645 for (i
= 0; i
< nneighbours
; i
++) {
646 j
= neighbours
[i
].pos
;
647 s
= neighbours
[i
].slash
;
648 if (soln
[j
] == 0 && j
!= mj1
&& j
!= mj2
)
649 fill_square(w
, h
, j
%w
, j
/w
, (nl ? s
: -s
), soln
,
653 done_something
= TRUE
;
654 } else if (nu
== 2 && nl
== 1 && difficulty
> DIFF_EASY
) {
656 * If we have precisely two undecided squares
657 * and precisely one line to place between
658 * them, _and_ those squares are adjacent, then
659 * we can mark them as equivalent to one
662 * This even applies if meq >= 0: if we have a
663 * 2 clue point and two of its neighbours are
664 * already marked equivalent, we can indeed
665 * mark the other two as equivalent.
667 * We don't bother with this on DIFF_EASY,
668 * since we wouldn't have used the results
672 for (i
= 0; i
< nneighbours
; i
++) {
673 j
= neighbours
[i
].pos
;
674 if (soln
[j
] == 0 && j
!= mj1
&& j
!= mj2
) {
677 else if (last
== i
-1 || (last
== 0 && i
== 3))
678 break; /* found a pair */
681 if (i
< nneighbours
) {
686 * neighbours[last] and neighbours[i] are
687 * the pair. Mark them equivalent.
689 #ifdef SOLVER_DIAGNOSTICS
692 printf("since %d,%d == %d,%d, ",
693 mj1
%w
, mj1
/w
, mj2
%w
, mj2
/w
);
696 mj1
= neighbours
[last
].pos
;
697 mj2
= neighbours
[i
].pos
;
698 #ifdef SOLVER_DIAGNOSTICS
700 printf("clue point at %d,%d implies %d,%d == %d,"
701 "%d\n", x
, y
, mj1
%w
, mj1
/w
, mj2
%w
, mj2
/w
);
703 mj1
= dsf_canonify(sc
->equiv
, mj1
);
704 sv1
= sc
->slashval
[mj1
];
705 mj2
= dsf_canonify(sc
->equiv
, mj2
);
706 sv2
= sc
->slashval
[mj2
];
707 if (sv1
!= 0 && sv2
!= 0 && sv1
!= sv2
) {
708 #ifdef SOLVER_DIAGNOSTICS
710 printf("merged two equivalence classes with"
711 " different slash values!\n");
715 sv1
= sv1 ? sv1
: sv2
;
716 dsf_merge(sc
->equiv
, mj1
, mj2
);
717 mj1
= dsf_canonify(sc
->equiv
, mj1
);
718 sc
->slashval
[mj1
] = sv1
;
727 * Failing that, we now apply the second condition, which
728 * is that no square may be filled in such a way as to form
729 * a loop. Also in this loop (since it's over squares
730 * rather than points), we check slashval to see if we've
731 * already filled in another square in the same equivalence
734 * The slashval check is disabled on DIFF_EASY, as is dead
735 * end avoidance. Only _immediate_ loop avoidance remains.
737 for (y
= 0; y
< h
; y
++)
738 for (x
= 0; x
< w
; x
++) {
741 #ifdef SOLVER_DIAGNOSTICS
742 char *reason
= "<internal error>";
746 continue; /* got this one already */
751 if (difficulty
> DIFF_EASY
)
752 v
= sc
->slashval
[dsf_canonify(sc
->equiv
, y
*w
+x
)];
757 * Try to rule out connectivity between (x,y) and
758 * (x+1,y+1); if successful, we will deduce that we
759 * must have a forward slash.
761 c1
= dsf_canonify(sc
->connected
, y
*W
+x
);
762 c2
= dsf_canonify(sc
->connected
, (y
+1)*W
+(x
+1));
765 #ifdef SOLVER_DIAGNOSTICS
766 reason
= "simple loop avoidance";
769 if (difficulty
> DIFF_EASY
&&
770 !sc
->border
[c1
] && !sc
->border
[c2
] &&
771 sc
->exits
[c1
] <= 1 && sc
->exits
[c2
] <= 1) {
773 #ifdef SOLVER_DIAGNOSTICS
774 reason
= "dead end avoidance";
779 #ifdef SOLVER_DIAGNOSTICS
780 reason
= "equivalence to an already filled square";
785 * Now do the same between (x+1,y) and (x,y+1), to
786 * see if we are required to have a backslash.
788 c1
= dsf_canonify(sc
->connected
, y
*W
+(x
+1));
789 c2
= dsf_canonify(sc
->connected
, (y
+1)*W
+x
);
792 #ifdef SOLVER_DIAGNOSTICS
793 reason
= "simple loop avoidance";
796 if (difficulty
> DIFF_EASY
&&
797 !sc
->border
[c1
] && !sc
->border
[c2
] &&
798 sc
->exits
[c1
] <= 1 && sc
->exits
[c2
] <= 1) {
800 #ifdef SOLVER_DIAGNOSTICS
801 reason
= "dead end avoidance";
806 #ifdef SOLVER_DIAGNOSTICS
807 reason
= "equivalence to an already filled square";
813 * No consistent value for this at all!
815 #ifdef SOLVER_DIAGNOSTICS
817 printf("%d,%d has no consistent slash!\n", x
, y
);
819 return 0; /* impossible */
823 #ifdef SOLVER_DIAGNOSTICS
825 printf("employing %s\n", reason
);
827 fill_square(w
, h
, x
, y
, +1, soln
, sc
->connected
, sc
);
828 done_something
= TRUE
;
830 #ifdef SOLVER_DIAGNOSTICS
832 printf("employing %s\n", reason
);
834 fill_square(w
, h
, x
, y
, -1, soln
, sc
->connected
, sc
);
835 done_something
= TRUE
;
839 } while (done_something
);
842 * Solver can make no more progress. See if the grid is full.
844 for (i
= 0; i
< w
*h
; i
++)
846 return 2; /* failed to converge */
847 return 1; /* success */
851 * Filled-grid generator.
853 static void slant_generate(int w
, int h
, signed char *soln
, random_state
*rs
)
855 int W
= w
+1, H
= h
+1;
857 int *connected
, *indices
;
862 memset(soln
, 0, w
*h
);
865 * Establish a disjoint set forest for tracking connectedness
866 * between grid points.
868 connected
= snewn(W
*H
, int);
869 for (i
= 0; i
< W
*H
; i
++)
870 connected
[i
] = i
; /* initially all distinct */
873 * Prepare a list of the squares in the grid, and fill them in
876 indices
= snewn(w
*h
, int);
877 for (i
= 0; i
< w
*h
; i
++)
879 shuffle(indices
, w
*h
, sizeof(*indices
), rs
);
882 * Fill in each one in turn.
884 for (i
= 0; i
< w
*h
; i
++) {
890 fs
= (dsf_canonify(connected
, y
*W
+x
) ==
891 dsf_canonify(connected
, (y
+1)*W
+(x
+1)));
892 bs
= (dsf_canonify(connected
, (y
+1)*W
+x
) ==
893 dsf_canonify(connected
, y
*W
+(x
+1)));
896 * It isn't possible to get into a situation where we
897 * aren't allowed to place _either_ type of slash in a
898 * square. Thus, filled-grid generation never has to
901 * Proof (thanks to Gareth Taylor):
903 * If it were possible, it would have to be because there
904 * was an existing path (not using this square) between the
905 * top-left and bottom-right corners of this square, and
906 * another between the other two. These two paths would
907 * have to cross at some point.
909 * Obviously they can't cross in the middle of a square, so
910 * they must cross by sharing a point in common. But this
911 * isn't possible either: if you chessboard-colour all the
912 * points on the grid, you find that any continuous
913 * diagonal path is entirely composed of points of the same
914 * colour. And one of our two hypothetical paths is between
915 * two black points, and the other is between two white
916 * points - therefore they can have no point in common. []
920 v
= fs ?
+1 : bs ?
-1 : 2 * random_upto(rs
, 2) - 1;
921 fill_square(w
, h
, x
, y
, v
, soln
, connected
, NULL
);
928 static char *new_game_desc(game_params
*params
, random_state
*rs
,
929 char **aux
, int interactive
)
931 int w
= params
->w
, h
= params
->h
, W
= w
+1, H
= h
+1;
932 signed char *soln
, *tmpsoln
, *clues
;
934 struct solver_scratch
*sc
;
938 soln
= snewn(w
*h
, signed char);
939 tmpsoln
= snewn(w
*h
, signed char);
940 clues
= snewn(W
*H
, signed char);
941 clueindices
= snewn(W
*H
, int);
942 sc
= new_scratch(w
, h
);
946 * Create the filled grid.
948 slant_generate(w
, h
, soln
, rs
);
951 * Fill in the complete set of clues.
953 for (y
= 0; y
< H
; y
++)
954 for (x
= 0; x
< W
; x
++) {
957 if (x
> 0 && y
> 0 && soln
[(y
-1)*w
+(x
-1)] == -1) v
++;
958 if (x
> 0 && y
< h
&& soln
[y
*w
+(x
-1)] == +1) v
++;
959 if (x
< w
&& y
> 0 && soln
[(y
-1)*w
+x
] == +1) v
++;
960 if (x
< w
&& y
< h
&& soln
[y
*w
+x
] == -1) v
++;
966 * With all clue points filled in, all puzzles are easy: we can
967 * simply process the clue points in lexicographic order, and
968 * at each clue point we will always have at most one square
969 * undecided, which we can then fill in uniquely.
971 assert(slant_solve(w
, h
, clues
, tmpsoln
, sc
, DIFF_EASY
) == 1);
974 * Remove as many clues as possible while retaining solubility.
976 * In DIFF_HARD mode, we prioritise the removal of obvious
977 * starting points (4s, 0s, border 2s and corner 1s), on
978 * the grounds that having as few of these as possible
979 * seems like a good thing. In particular, we can often get
980 * away without _any_ completely obvious starting points,
981 * which is even better.
983 for (i
= 0; i
< W
*H
; i
++)
985 shuffle(clueindices
, W
*H
, sizeof(*clueindices
), rs
);
986 for (j
= 0; j
< 2; j
++) {
987 for (i
= 0; i
< W
*H
; i
++) {
990 y
= clueindices
[i
] / W
;
991 x
= clueindices
[i
] % W
;
995 * Identify which pass we should process this point
996 * in. If it's an obvious start point, _or_ we're
997 * in DIFF_EASY, then it goes in pass 0; otherwise
1000 xb
= (x
== 0 || x
== W
-1);
1001 yb
= (y
== 0 || y
== H
-1);
1002 if (params
->diff
== DIFF_EASY
|| v
== 4 || v
== 0 ||
1003 (v
== 2 && (xb
||yb
)) || (v
== 1 && xb
&& yb
))
1010 if (slant_solve(w
, h
, clues
, tmpsoln
, sc
,
1012 clues
[y
*W
+x
] = v
; /* put it back */
1018 * And finally, verify that the grid is of _at least_ the
1019 * requested difficulty, by running the solver one level
1020 * down and verifying that it can't manage it.
1022 } while (params
->diff
> 0 &&
1023 slant_solve(w
, h
, clues
, tmpsoln
, sc
, params
->diff
- 1) <= 1);
1026 * Now we have the clue set as it will be presented to the
1027 * user. Encode it in a game desc.
1033 desc
= snewn(W
*H
+1, char);
1036 for (i
= 0; i
<= W
*H
; i
++) {
1037 int n
= (i
< W
*H ? clues
[i
] : -2);
1044 int c
= 'a' - 1 + run
;
1048 run
-= c
- ('a' - 1);
1056 assert(p
- desc
<= W
*H
);
1058 desc
= sresize(desc
, p
- desc
, char);
1062 * Encode the solution as an aux_info.
1066 *aux
= auxbuf
= snewn(w
*h
+1, char);
1067 for (i
= 0; i
< w
*h
; i
++)
1068 auxbuf
[i
] = soln
[i
] < 0 ?
'\\' : '/';
1081 static char *validate_desc(game_params
*params
, char *desc
)
1083 int w
= params
->w
, h
= params
->h
, W
= w
+1, H
= h
+1;
1089 if (n
>= 'a' && n
<= 'z') {
1090 squares
+= n
- 'a' + 1;
1091 } else if (n
>= '0' && n
<= '4') {
1094 return "Invalid character in game description";
1098 return "Not enough data to fill grid";
1101 return "Too much data to fit in grid";
1106 static game_state
*new_game(midend_data
*me
, game_params
*params
, char *desc
)
1108 int w
= params
->w
, h
= params
->h
, W
= w
+1, H
= h
+1;
1109 game_state
*state
= snew(game_state
);
1114 state
->soln
= snewn(w
*h
, signed char);
1115 memset(state
->soln
, 0, w
*h
);
1116 state
->completed
= state
->used_solve
= FALSE
;
1117 state
->errors
= snewn(W
*H
, unsigned char);
1118 memset(state
->errors
, 0, W
*H
);
1120 state
->clues
= snew(game_clues
);
1121 state
->clues
->w
= w
;
1122 state
->clues
->h
= h
;
1123 state
->clues
->clues
= snewn(W
*H
, signed char);
1124 state
->clues
->refcount
= 1;
1125 state
->clues
->tmpsoln
= snewn(w
*h
, signed char);
1126 memset(state
->clues
->clues
, -1, W
*H
);
1129 if (n
>= 'a' && n
<= 'z') {
1130 squares
+= n
- 'a' + 1;
1131 } else if (n
>= '0' && n
<= '4') {
1132 state
->clues
->clues
[squares
++] = n
- '0';
1134 assert(!"can't get here");
1136 assert(squares
== area
);
1141 static game_state
*dup_game(game_state
*state
)
1143 int w
= state
->p
.w
, h
= state
->p
.h
, W
= w
+1, H
= h
+1;
1144 game_state
*ret
= snew(game_state
);
1147 ret
->clues
= state
->clues
;
1148 ret
->clues
->refcount
++;
1149 ret
->completed
= state
->completed
;
1150 ret
->used_solve
= state
->used_solve
;
1152 ret
->soln
= snewn(w
*h
, signed char);
1153 memcpy(ret
->soln
, state
->soln
, w
*h
);
1155 ret
->errors
= snewn(W
*H
, unsigned char);
1156 memcpy(ret
->errors
, state
->errors
, W
*H
);
1161 static void free_game(game_state
*state
)
1163 sfree(state
->errors
);
1165 assert(state
->clues
);
1166 if (--state
->clues
->refcount
<= 0) {
1167 sfree(state
->clues
->clues
);
1168 sfree(state
->clues
->tmpsoln
);
1169 sfree(state
->clues
);
1175 * Utility function to return the current degree of a vertex. If
1176 * `anti' is set, it returns the number of filled-in edges
1177 * surrounding the point which _don't_ connect to it; thus 4 minus
1178 * its anti-degree is the maximum degree it could have if all the
1179 * empty spaces around it were filled in.
1181 * (Yes, _4_ minus its anti-degree even if it's a border vertex.)
1183 * If ret > 0, *sx and *sy are set to the coordinates of one of the
1184 * squares that contributed to it.
1186 static int vertex_degree(int w
, int h
, signed char *soln
, int x
, int y
,
1187 int anti
, int *sx
, int *sy
)
1191 assert(x
>= 0 && x
<= w
&& y
>= 0 && y
<= h
);
1192 if (x
> 0 && y
> 0 && soln
[(y
-1)*w
+(x
-1)] - anti
< 0) {
1197 if (x
> 0 && y
< h
&& soln
[y
*w
+(x
-1)] + anti
> 0) {
1202 if (x
< w
&& y
> 0 && soln
[(y
-1)*w
+x
] + anti
> 0) {
1207 if (x
< w
&& y
< h
&& soln
[y
*w
+x
] - anti
< 0) {
1213 return anti ?
4 - ret
: ret
;
1216 static int check_completion(game_state
*state
)
1218 int w
= state
->p
.w
, h
= state
->p
.h
, W
= w
+1, H
= h
+1;
1219 int x
, y
, err
= FALSE
;
1222 memset(state
->errors
, 0, W
*H
);
1225 * An easy way to do loop checking would be by means of the
1226 * same dsf technique we've used elsewhere (loop over all edges
1227 * in the grid, joining vertices together into equivalence
1228 * classes when connected by an edge, and raise the alarm when
1229 * an edge joins two already-equivalent vertices). However, a
1230 * better approach is to repeatedly remove the single edge
1231 * connecting to any degree-1 vertex, and then see if there are
1232 * any edges left over; if so, precisely those edges are part
1233 * of loops, which means we can highlight them as errors for
1236 * We use the `tmpsoln' scratch space in the shared clues
1237 * structure, to avoid mallocing too often.
1239 ts
= state
->clues
->tmpsoln
;
1240 memcpy(ts
, state
->soln
, w
*h
);
1241 for (y
= 0; y
< H
; y
++)
1242 for (x
= 0; x
< W
; x
++) {
1246 * Every time we disconnect a vertex like this, there
1247 * is precisely one other vertex which might have
1248 * become degree 1; so we follow the trail as far as it
1249 * leads. This ensures that we don't have to make more
1250 * than one loop over the grid, because whenever a
1251 * degree-1 vertex comes into existence somewhere we've
1252 * already looked, we immediately remove it again.
1253 * Hence one loop over the grid is adequate; and
1254 * moreover, this algorithm visits every vertex at most
1255 * twice (once in the loop and possibly once more as a
1256 * result of following a trail) so it has linear time
1257 * in the area of the grid.
1259 while (vertex_degree(w
, h
, ts
, vx
, vy
, FALSE
, &sx
, &sy
) == 1) {
1261 vx
= vx
+ 1 + (sx
- vx
) * 2;
1262 vy
= vy
+ 1 + (sy
- vy
) * 2;
1267 * Now mark any remaining edges with ERR_SQUARE.
1269 for (y
= 0; y
< h
; y
++)
1270 for (x
= 0; x
< w
; x
++)
1272 state
->errors
[y
*W
+x
] |= ERR_SQUARE
;
1277 * Now go through and check the degree of each clue vertex, and
1278 * mark it with ERR_VERTEX if it cannot be fulfilled.
1280 for (y
= 0; y
< H
; y
++)
1281 for (x
= 0; x
< W
; x
++) {
1284 if ((c
= state
->clues
->clues
[y
*W
+x
]) < 0)
1288 * Check to see if there are too many connections to
1289 * this vertex _or_ too many non-connections. Either is
1290 * grounds for marking the vertex as erroneous.
1292 if (vertex_degree(w
, h
, state
->soln
, x
, y
,
1293 FALSE
, NULL
, NULL
) > c
||
1294 vertex_degree(w
, h
, state
->soln
, x
, y
,
1295 TRUE
, NULL
, NULL
) > 4-c
) {
1296 state
->errors
[y
*W
+x
] |= ERR_VERTEX
;
1302 * Now our actual victory condition is that (a) none of the
1303 * above code marked anything as erroneous, and (b) every
1304 * square has an edge in it.
1310 for (y
= 0; y
< h
; y
++)
1311 for (x
= 0; x
< w
; x
++)
1312 if (state
->soln
[y
*w
+x
] == 0)
1318 static char *solve_game(game_state
*state
, game_state
*currstate
,
1319 char *aux
, char **error
)
1321 int w
= state
->p
.w
, h
= state
->p
.h
;
1324 int free_soln
= FALSE
;
1325 char *move
, buf
[80];
1326 int movelen
, movesize
;
1331 * If we already have the solution, save ourselves some
1334 soln
= (signed char *)aux
;
1335 bs
= (signed char)'\\';
1338 struct solver_scratch
*sc
= new_scratch(w
, h
);
1339 soln
= snewn(w
*h
, signed char);
1341 ret
= slant_solve(w
, h
, state
->clues
->clues
, soln
, sc
, DIFF_HARD
);
1346 *error
= "This puzzle is not self-consistent";
1348 *error
= "Unable to find a unique solution for this puzzle";
1355 * Construct a move string which turns the current state into
1359 move
= snewn(movesize
, char);
1361 move
[movelen
++] = 'S';
1362 move
[movelen
] = '\0';
1363 for (y
= 0; y
< h
; y
++)
1364 for (x
= 0; x
< w
; x
++) {
1365 int v
= (soln
[y
*w
+x
] == bs ?
-1 : +1);
1366 if (state
->soln
[y
*w
+x
] != v
) {
1367 int len
= sprintf(buf
, ";%c%d,%d", (int)(v
< 0 ?
'\\' : '/'), x
, y
);
1368 if (movelen
+ len
>= movesize
) {
1369 movesize
= movelen
+ len
+ 256;
1370 move
= sresize(move
, movesize
, char);
1372 strcpy(move
+ movelen
, buf
);
1383 static char *game_text_format(game_state
*state
)
1385 int w
= state
->p
.w
, h
= state
->p
.h
, W
= w
+1, H
= h
+1;
1390 * There are h+H rows of w+W columns.
1392 len
= (h
+H
) * (w
+W
+1) + 1;
1393 ret
= snewn(len
, char);
1396 for (y
= 0; y
< H
; y
++) {
1397 for (x
= 0; x
< W
; x
++) {
1398 if (state
->clues
->clues
[y
*W
+x
] >= 0)
1399 *p
++ = state
->clues
->clues
[y
*W
+x
] + '0';
1407 for (x
= 0; x
< W
; x
++) {
1410 if (state
->soln
[y
*w
+x
] != 0)
1411 *p
++ = (state
->soln
[y
*w
+x
] < 0 ?
'\\' : '/');
1421 assert(p
- ret
== len
);
1425 static game_ui
*new_ui(game_state
*state
)
1430 static void free_ui(game_ui
*ui
)
1434 static char *encode_ui(game_ui
*ui
)
1439 static void decode_ui(game_ui
*ui
, char *encoding
)
1443 static void game_changed_state(game_ui
*ui
, game_state
*oldstate
,
1444 game_state
*newstate
)
1448 #define PREFERRED_TILESIZE 32
1449 #define TILESIZE (ds->tilesize)
1450 #define BORDER TILESIZE
1451 #define CLUE_RADIUS (TILESIZE / 3)
1452 #define CLUE_TEXTSIZE (TILESIZE / 2)
1453 #define COORD(x) ( (x) * TILESIZE + BORDER )
1454 #define FROMCOORD(x) ( ((x) - BORDER + TILESIZE) / TILESIZE - 1 )
1456 #define FLASH_TIME 0.30F
1459 * Bit fields in the `grid' and `todraw' elements of the drawstate.
1461 #define BACKSLASH 0x00000001L
1462 #define FORWSLASH 0x00000002L
1463 #define L_T 0x00000004L
1464 #define ERR_L_T 0x00000008L
1465 #define L_B 0x00000010L
1466 #define ERR_L_B 0x00000020L
1467 #define T_L 0x00000040L
1468 #define ERR_T_L 0x00000080L
1469 #define T_R 0x00000100L
1470 #define ERR_T_R 0x00000200L
1471 #define C_TL 0x00000400L
1472 #define ERR_C_TL 0x00000800L
1473 #define FLASH 0x00001000L
1474 #define ERRSLASH 0x00002000L
1475 #define ERR_TL 0x00004000L
1476 #define ERR_TR 0x00008000L
1477 #define ERR_BL 0x00010000L
1478 #define ERR_BR 0x00020000L
1480 struct game_drawstate
{
1487 static char *interpret_move(game_state
*state
, game_ui
*ui
, game_drawstate
*ds
,
1488 int x
, int y
, int button
)
1490 int w
= state
->p
.w
, h
= state
->p
.h
;
1492 if (button
== LEFT_BUTTON
|| button
== RIGHT_BUTTON
) {
1497 * This is an utterly awful hack which I should really sort out
1498 * by means of a proper configuration mechanism. One Slant
1499 * player has observed that they prefer the mouse buttons to
1500 * function exactly the opposite way round, so here's a
1501 * mechanism for environment-based configuration. I cache the
1502 * result in a global variable - yuck! - to avoid repeated
1506 static int swap_buttons
= -1;
1507 if (swap_buttons
< 0) {
1508 char *env
= getenv("SLANT_SWAP_BUTTONS");
1509 swap_buttons
= (env
&& (env
[0] == 'y' || env
[0] == 'Y'));
1512 if (button
== LEFT_BUTTON
)
1513 button
= RIGHT_BUTTON
;
1515 button
= LEFT_BUTTON
;
1521 if (x
< 0 || y
< 0 || x
>= w
|| y
>= h
)
1524 if (button
== LEFT_BUTTON
) {
1526 * Left-clicking cycles blank -> \ -> / -> blank.
1528 v
= state
->soln
[y
*w
+x
] - 1;
1533 * Right-clicking cycles blank -> / -> \ -> blank.
1535 v
= state
->soln
[y
*w
+x
] + 1;
1540 sprintf(buf
, "%c%d,%d", (int)(v
==-1 ?
'\\' : v
==+1 ?
'/' : 'C'), x
, y
);
1547 static game_state
*execute_move(game_state
*state
, char *move
)
1549 int w
= state
->p
.w
, h
= state
->p
.h
;
1552 game_state
*ret
= dup_game(state
);
1557 ret
->used_solve
= TRUE
;
1559 } else if (c
== '\\' || c
== '/' || c
== 'C') {
1561 if (sscanf(move
, "%d,%d%n", &x
, &y
, &n
) != 2 ||
1562 x
< 0 || y
< 0 || x
>= w
|| y
>= h
) {
1566 ret
->soln
[y
*w
+x
] = (c
== '\\' ?
-1 : c
== '/' ?
+1 : 0);
1581 * We never clear the `completed' flag, but we must always
1582 * re-run the completion check because it also highlights
1583 * errors in the grid.
1585 ret
->completed
= check_completion(ret
) || ret
->completed
;
1590 /* ----------------------------------------------------------------------
1594 static void game_compute_size(game_params
*params
, int tilesize
,
1597 /* fool the macros */
1598 struct dummy
{ int tilesize
; } dummy
= { tilesize
}, *ds
= &dummy
;
1600 *x
= 2 * BORDER
+ params
->w
* TILESIZE
+ 1;
1601 *y
= 2 * BORDER
+ params
->h
* TILESIZE
+ 1;
1604 static void game_set_size(game_drawstate
*ds
, game_params
*params
,
1607 ds
->tilesize
= tilesize
;
1610 static float *game_colours(frontend
*fe
, game_state
*state
, int *ncolours
)
1612 float *ret
= snewn(3 * NCOLOURS
, float);
1614 frontend_default_colour(fe
, &ret
[COL_BACKGROUND
* 3]);
1616 ret
[COL_GRID
* 3 + 0] = ret
[COL_BACKGROUND
* 3 + 0] * 0.7F
;
1617 ret
[COL_GRID
* 3 + 1] = ret
[COL_BACKGROUND
* 3 + 1] * 0.7F
;
1618 ret
[COL_GRID
* 3 + 2] = ret
[COL_BACKGROUND
* 3 + 2] * 0.7F
;
1620 ret
[COL_INK
* 3 + 0] = 0.0F
;
1621 ret
[COL_INK
* 3 + 1] = 0.0F
;
1622 ret
[COL_INK
* 3 + 2] = 0.0F
;
1624 ret
[COL_SLANT1
* 3 + 0] = 0.0F
;
1625 ret
[COL_SLANT1
* 3 + 1] = 0.0F
;
1626 ret
[COL_SLANT1
* 3 + 2] = 0.0F
;
1628 ret
[COL_SLANT2
* 3 + 0] = 0.0F
;
1629 ret
[COL_SLANT2
* 3 + 1] = 0.0F
;
1630 ret
[COL_SLANT2
* 3 + 2] = 0.0F
;
1632 ret
[COL_ERROR
* 3 + 0] = 1.0F
;
1633 ret
[COL_ERROR
* 3 + 1] = 0.0F
;
1634 ret
[COL_ERROR
* 3 + 2] = 0.0F
;
1636 *ncolours
= NCOLOURS
;
1640 static game_drawstate
*game_new_drawstate(game_state
*state
)
1642 int w
= state
->p
.w
, h
= state
->p
.h
;
1644 struct game_drawstate
*ds
= snew(struct game_drawstate
);
1647 ds
->started
= FALSE
;
1648 ds
->grid
= snewn((w
+2)*(h
+2), long);
1649 ds
->todraw
= snewn((w
+2)*(h
+2), long);
1650 for (i
= 0; i
< (w
+2)*(h
+2); i
++)
1651 ds
->grid
[i
] = ds
->todraw
[i
] = -1;
1656 static void game_free_drawstate(game_drawstate
*ds
)
1663 static void draw_clue(frontend
*fe
, game_drawstate
*ds
,
1664 int x
, int y
, long v
, long err
)
1667 int ccol
= ((x
^ y
) & 1) ? COL_SLANT1
: COL_SLANT2
;
1668 int tcol
= err ? COL_ERROR
: COL_INK
;
1675 draw_circle(fe
, COORD(x
), COORD(y
), CLUE_RADIUS
, COL_BACKGROUND
, ccol
);
1676 draw_text(fe
, COORD(x
), COORD(y
), FONT_VARIABLE
,
1677 CLUE_TEXTSIZE
, ALIGN_VCENTRE
|ALIGN_HCENTRE
, tcol
, p
);
1680 static void draw_tile(frontend
*fe
, game_drawstate
*ds
, game_clues
*clues
,
1681 int x
, int y
, long v
)
1683 int w
= clues
->w
, h
= clues
->h
, W
= w
+1 /*, H = h+1 */;
1684 int chesscolour
= (x
^ y
) & 1;
1685 int fscol
= chesscolour ? COL_SLANT2
: COL_SLANT1
;
1686 int bscol
= chesscolour ? COL_SLANT1
: COL_SLANT2
;
1688 clip(fe
, COORD(x
), COORD(y
), TILESIZE
, TILESIZE
);
1690 draw_rect(fe
, COORD(x
), COORD(y
), TILESIZE
, TILESIZE
,
1691 (v
& FLASH
) ? COL_GRID
: COL_BACKGROUND
);
1694 * Draw the grid lines.
1696 if (x
>= 0 && x
< w
&& y
>= 0)
1697 draw_rect(fe
, COORD(x
), COORD(y
), TILESIZE
+1, 1, COL_GRID
);
1698 if (x
>= 0 && x
< w
&& y
< h
)
1699 draw_rect(fe
, COORD(x
), COORD(y
+1), TILESIZE
+1, 1, COL_GRID
);
1700 if (y
>= 0 && y
< h
&& x
>= 0)
1701 draw_rect(fe
, COORD(x
), COORD(y
), 1, TILESIZE
+1, COL_GRID
);
1702 if (y
>= 0 && y
< h
&& x
< w
)
1703 draw_rect(fe
, COORD(x
+1), COORD(y
), 1, TILESIZE
+1, COL_GRID
);
1704 if (x
== -1 && y
== -1)
1705 draw_rect(fe
, COORD(x
+1), COORD(y
+1), 1, 1, COL_GRID
);
1706 if (x
== -1 && y
== h
)
1707 draw_rect(fe
, COORD(x
+1), COORD(y
), 1, 1, COL_GRID
);
1708 if (x
== w
&& y
== -1)
1709 draw_rect(fe
, COORD(x
), COORD(y
+1), 1, 1, COL_GRID
);
1710 if (x
== w
&& y
== h
)
1711 draw_rect(fe
, COORD(x
), COORD(y
), 1, 1, COL_GRID
);
1716 if (v
& BACKSLASH
) {
1717 int scol
= (v
& ERRSLASH
) ? COL_ERROR
: bscol
;
1718 draw_line(fe
, COORD(x
), COORD(y
), COORD(x
+1), COORD(y
+1), scol
);
1719 draw_line(fe
, COORD(x
)+1, COORD(y
), COORD(x
+1), COORD(y
+1)-1,
1721 draw_line(fe
, COORD(x
), COORD(y
)+1, COORD(x
+1)-1, COORD(y
+1),
1723 } else if (v
& FORWSLASH
) {
1724 int scol
= (v
& ERRSLASH
) ? COL_ERROR
: fscol
;
1725 draw_line(fe
, COORD(x
+1), COORD(y
), COORD(x
), COORD(y
+1), scol
);
1726 draw_line(fe
, COORD(x
+1)-1, COORD(y
), COORD(x
), COORD(y
+1)-1,
1728 draw_line(fe
, COORD(x
+1), COORD(y
)+1, COORD(x
)+1, COORD(y
+1),
1733 * Draw dots on the grid corners that appear if a slash is in a
1734 * neighbouring cell.
1736 if (v
& (L_T
| BACKSLASH
))
1737 draw_rect(fe
, COORD(x
), COORD(y
)+1, 1, 1,
1738 (v
& ERR_L_T ? COL_ERROR
: bscol
));
1739 if (v
& (L_B
| FORWSLASH
))
1740 draw_rect(fe
, COORD(x
), COORD(y
+1)-1, 1, 1,
1741 (v
& ERR_L_B ? COL_ERROR
: fscol
));
1742 if (v
& (T_L
| BACKSLASH
))
1743 draw_rect(fe
, COORD(x
)+1, COORD(y
), 1, 1,
1744 (v
& ERR_T_L ? COL_ERROR
: bscol
));
1745 if (v
& (T_R
| FORWSLASH
))
1746 draw_rect(fe
, COORD(x
+1)-1, COORD(y
), 1, 1,
1747 (v
& ERR_T_R ? COL_ERROR
: fscol
));
1748 if (v
& (C_TL
| BACKSLASH
))
1749 draw_rect(fe
, COORD(x
), COORD(y
), 1, 1,
1750 (v
& ERR_C_TL ? COL_ERROR
: bscol
));
1753 * And finally the clues at the corners.
1755 if (x
>= 0 && y
>= 0)
1756 draw_clue(fe
, ds
, x
, y
, clues
->clues
[y
*W
+x
], v
& ERR_TL
);
1757 if (x
< w
&& y
>= 0)
1758 draw_clue(fe
, ds
, x
+1, y
, clues
->clues
[y
*W
+(x
+1)], v
& ERR_TR
);
1759 if (x
>= 0 && y
< h
)
1760 draw_clue(fe
, ds
, x
, y
+1, clues
->clues
[(y
+1)*W
+x
], v
& ERR_BL
);
1762 draw_clue(fe
, ds
, x
+1, y
+1, clues
->clues
[(y
+1)*W
+(x
+1)], v
& ERR_BR
);
1765 draw_update(fe
, COORD(x
), COORD(y
), TILESIZE
, TILESIZE
);
1768 static void game_redraw(frontend
*fe
, game_drawstate
*ds
, game_state
*oldstate
,
1769 game_state
*state
, int dir
, game_ui
*ui
,
1770 float animtime
, float flashtime
)
1772 int w
= state
->p
.w
, h
= state
->p
.h
, W
= w
+1, H
= h
+1;
1777 flashing
= (int)(flashtime
* 3 / FLASH_TIME
) != 1;
1783 game_compute_size(&state
->p
, TILESIZE
, &ww
, &wh
);
1784 draw_rect(fe
, 0, 0, ww
, wh
, COL_BACKGROUND
);
1785 draw_update(fe
, 0, 0, ww
, wh
);
1790 * Loop over the grid and work out where all the slashes are.
1791 * We need to do this because a slash in one square affects the
1792 * drawing of the next one along.
1794 for (y
= -1; y
<= h
; y
++)
1795 for (x
= -1; x
<= w
; x
++) {
1796 if (x
>= 0 && x
< w
&& y
>= 0 && y
< h
)
1797 ds
->todraw
[(y
+1)*(w
+2)+(x
+1)] = flashing ? FLASH
: 0;
1799 ds
->todraw
[(y
+1)*(w
+2)+(x
+1)] = 0;
1802 for (y
= 0; y
< h
; y
++) {
1803 for (x
= 0; x
< w
; x
++) {
1804 int err
= state
->errors
[y
*W
+x
] & ERR_SQUARE
;
1806 if (state
->soln
[y
*w
+x
] < 0) {
1807 ds
->todraw
[(y
+1)*(w
+2)+(x
+1)] |= BACKSLASH
;
1808 ds
->todraw
[(y
+2)*(w
+2)+(x
+1)] |= T_R
;
1809 ds
->todraw
[(y
+1)*(w
+2)+(x
+2)] |= L_B
;
1810 ds
->todraw
[(y
+2)*(w
+2)+(x
+2)] |= C_TL
;
1812 ds
->todraw
[(y
+1)*(w
+2)+(x
+1)] |= ERRSLASH
|
1813 ERR_T_L
| ERR_L_T
| ERR_C_TL
;
1814 ds
->todraw
[(y
+2)*(w
+2)+(x
+1)] |= ERR_T_R
;
1815 ds
->todraw
[(y
+1)*(w
+2)+(x
+2)] |= ERR_L_B
;
1816 ds
->todraw
[(y
+2)*(w
+2)+(x
+2)] |= ERR_C_TL
;
1818 } else if (state
->soln
[y
*w
+x
] > 0) {
1819 ds
->todraw
[(y
+1)*(w
+2)+(x
+1)] |= FORWSLASH
;
1820 ds
->todraw
[(y
+1)*(w
+2)+(x
+2)] |= L_T
| C_TL
;
1821 ds
->todraw
[(y
+2)*(w
+2)+(x
+1)] |= T_L
| C_TL
;
1823 ds
->todraw
[(y
+1)*(w
+2)+(x
+1)] |= ERRSLASH
|
1825 ds
->todraw
[(y
+1)*(w
+2)+(x
+2)] |= ERR_L_T
| ERR_C_TL
;
1826 ds
->todraw
[(y
+2)*(w
+2)+(x
+1)] |= ERR_T_L
| ERR_C_TL
;
1832 for (y
= 0; y
< H
; y
++)
1833 for (x
= 0; x
< W
; x
++)
1834 if (state
->errors
[y
*W
+x
] & ERR_VERTEX
) {
1835 ds
->todraw
[y
*(w
+2)+x
] |= ERR_BR
;
1836 ds
->todraw
[y
*(w
+2)+(x
+1)] |= ERR_BL
;
1837 ds
->todraw
[(y
+1)*(w
+2)+x
] |= ERR_TR
;
1838 ds
->todraw
[(y
+1)*(w
+2)+(x
+1)] |= ERR_TL
;
1842 * Now go through and draw the grid squares.
1844 for (y
= -1; y
<= h
; y
++) {
1845 for (x
= -1; x
<= w
; x
++) {
1846 if (ds
->todraw
[(y
+1)*(w
+2)+(x
+1)] != ds
->grid
[(y
+1)*(w
+2)+(x
+1)]) {
1847 draw_tile(fe
, ds
, state
->clues
, x
, y
,
1848 ds
->todraw
[(y
+1)*(w
+2)+(x
+1)]);
1849 ds
->grid
[(y
+1)*(w
+2)+(x
+1)] = ds
->todraw
[(y
+1)*(w
+2)+(x
+1)];
1855 static float game_anim_length(game_state
*oldstate
, game_state
*newstate
,
1856 int dir
, game_ui
*ui
)
1861 static float game_flash_length(game_state
*oldstate
, game_state
*newstate
,
1862 int dir
, game_ui
*ui
)
1864 if (!oldstate
->completed
&& newstate
->completed
&&
1865 !oldstate
->used_solve
&& !newstate
->used_solve
)
1871 static int game_wants_statusbar(void)
1876 static int game_timing_state(game_state
*state
, game_ui
*ui
)
1882 #define thegame slant
1885 const struct game thegame
= {
1886 "Slant", "games.slant",
1893 TRUE
, game_configure
, custom_params
,
1901 TRUE
, game_text_format
,
1909 PREFERRED_TILESIZE
, game_compute_size
, game_set_size
,
1912 game_free_drawstate
,
1916 game_wants_statusbar
,
1917 FALSE
, game_timing_state
,
1918 0, /* mouse_priorities */
1921 #ifdef STANDALONE_SOLVER
1926 * gcc -DSTANDALONE_SOLVER -o slantsolver slant.c malloc.c
1929 void frontend_default_colour(frontend
*fe
, float *output
) {}
1930 void draw_text(frontend
*fe
, int x
, int y
, int fonttype
, int fontsize
,
1931 int align
, int colour
, char *text
) {}
1932 void draw_rect(frontend
*fe
, int x
, int y
, int w
, int h
, int colour
) {}
1933 void draw_line(frontend
*fe
, int x1
, int y1
, int x2
, int y2
, int colour
) {}
1934 void draw_polygon(frontend
*fe
, int *coords
, int npoints
,
1935 int fillcolour
, int outlinecolour
) {}
1936 void draw_circle(frontend
*fe
, int cx
, int cy
, int radius
,
1937 int fillcolour
, int outlinecolour
) {}
1938 void clip(frontend
*fe
, int x
, int y
, int w
, int h
) {}
1939 void unclip(frontend
*fe
) {}
1940 void start_draw(frontend
*fe
) {}
1941 void draw_update(frontend
*fe
, int x
, int y
, int w
, int h
) {}
1942 void end_draw(frontend
*fe
) {}
1943 unsigned long random_bits(random_state
*state
, int bits
)
1944 { assert(!"Shouldn't get randomness"); return 0; }
1945 unsigned long random_upto(random_state
*state
, unsigned long limit
)
1946 { assert(!"Shouldn't get randomness"); return 0; }
1947 void shuffle(void *array
, int nelts
, int eltsize
, random_state
*rs
)
1948 { assert(!"Shouldn't get randomness"); }
1950 void fatal(char *fmt
, ...)
1954 fprintf(stderr
, "fatal error: ");
1957 vfprintf(stderr
, fmt
, ap
);
1960 fprintf(stderr
, "\n");
1964 int main(int argc
, char **argv
)
1968 char *id
= NULL
, *desc
, *err
;
1970 int ret
, diff
, really_verbose
= FALSE
;
1971 struct solver_scratch
*sc
;
1973 while (--argc
> 0) {
1975 if (!strcmp(p
, "-v")) {
1976 really_verbose
= TRUE
;
1977 } else if (!strcmp(p
, "-g")) {
1979 } else if (*p
== '-') {
1980 fprintf(stderr
, "%s: unrecognised option `%s'\n", argv
[0], p
);
1988 fprintf(stderr
, "usage: %s [-g | -v] <game_id>\n", argv
[0]);
1992 desc
= strchr(id
, ':');
1994 fprintf(stderr
, "%s: game id expects a colon in it\n", argv
[0]);
1999 p
= default_params();
2000 decode_params(p
, id
);
2001 err
= validate_desc(p
, desc
);
2003 fprintf(stderr
, "%s: %s\n", argv
[0], err
);
2006 s
= new_game(NULL
, p
, desc
);
2008 sc
= new_scratch(p
->w
, p
->h
);
2011 * When solving an Easy puzzle, we don't want to bother the
2012 * user with Hard-level deductions. For this reason, we grade
2013 * the puzzle internally before doing anything else.
2015 ret
= -1; /* placate optimiser */
2016 for (diff
= 0; diff
< DIFFCOUNT
; diff
++) {
2017 ret
= slant_solve(p
->w
, p
->h
, s
->clues
->clues
,
2023 if (diff
== DIFFCOUNT
) {
2025 printf("Difficulty rating: harder than Hard, or ambiguous\n");
2027 printf("Unable to find a unique solution\n");
2031 printf("Difficulty rating: impossible (no solution exists)\n");
2033 printf("Difficulty rating: %s\n", slant_diffnames
[diff
]);
2035 verbose
= really_verbose
;
2036 ret
= slant_solve(p
->w
, p
->h
, s
->clues
->clues
,
2039 printf("Puzzle is inconsistent\n");
2041 fputs(game_text_format(s
), stdout
);