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 {
85 #define ERR_SQUARE_TMP 4
91 unsigned char *errors;
93 int used_solve; /* used to suppress completion flash */
96 static game_params *default_params(void)
98 game_params *ret = snew(game_params);
101 ret->diff = DIFF_EASY;
106 static const struct game_params slant_presets[] = {
115 static int game_fetch_preset(int i, char **name, game_params **params)
120 if (i < 0 || i >= lenof(slant_presets))
123 ret = snew(game_params);
124 *ret = slant_presets[i];
126 sprintf(str, "%dx%d %s", ret->w, ret->h, slant_diffnames[ret->diff]);
133 static void free_params(game_params *params)
138 static game_params *dup_params(game_params *params)
140 game_params *ret = snew(game_params);
141 *ret = *params; /* structure copy */
145 static void decode_params(game_params *ret, char const *string)
147 ret->w = ret->h = atoi(string);
148 while (*string && isdigit((unsigned char)*string)) string++;
149 if (*string == 'x') {
151 ret->h = atoi(string);
152 while (*string && isdigit((unsigned char)*string)) string++;
154 if (*string == 'd') {
157 for (i = 0; i < DIFFCOUNT; i++)
158 if (*string == slant_diffchars[i])
160 if (*string) string++;
164 static char *encode_params(game_params *params, int full)
168 sprintf(data, "%dx%d", params->w, params->h);
170 sprintf(data + strlen(data), "d%c", slant_diffchars[params->diff]);
175 static config_item *game_configure(game_params *params)
180 ret = snewn(4, config_item);
182 ret[0].name = "Width";
183 ret[0].type = C_STRING;
184 sprintf(buf, "%d", params->w);
185 ret[0].sval = dupstr(buf);
188 ret[1].name = "Height";
189 ret[1].type = C_STRING;
190 sprintf(buf, "%d", params->h);
191 ret[1].sval = dupstr(buf);
194 ret[2].name = "Difficulty";
195 ret[2].type = C_CHOICES;
196 ret[2].sval = DIFFCONFIG;
197 ret[2].ival = params->diff;
207 static game_params *custom_params(config_item *cfg)
209 game_params *ret = snew(game_params);
211 ret->w = atoi(cfg[0].sval);
212 ret->h = atoi(cfg[1].sval);
213 ret->diff = cfg[2].ival;
218 static char *validate_params(game_params *params, int full)
221 * (At least at the time of writing this comment) The grid
222 * generator is actually capable of handling even zero grid
223 * dimensions without crashing. Puzzles with a zero-area grid
224 * are a bit boring, though, because they're already solved :-)
225 * And puzzles with a dimension of 1 can't be made Hard, which
226 * means the simplest thing is to forbid them altogether.
229 if (params->w < 2 || params->h < 2)
230 return "Width and height must both be at least two";
236 * Scratch space for solver.
238 struct solver_scratch {
240 * Disjoint set forest which tracks the connected sets of
246 * Counts the number of possible exits from each connected set
247 * of points. (That is, the number of possible _simultaneous_
248 * exits: an unconnected point labelled 2 has an exit count of
249 * 2 even if all four possible edges are still under
255 * Tracks whether each connected set of points includes a
258 unsigned char *border;
261 * Another disjoint set forest. This one tracks _squares_ which
262 * are known to slant in the same direction.
267 * Stores slash values which we know for an equivalence class.
268 * When we fill in a square, we set slashval[canonify(x)] to
269 * the same value as soln[x], so that we can then spot other
270 * squares equivalent to it and fill them in immediately via
271 * their known equivalence.
273 signed char *slashval;
276 * Useful to have this information automatically passed to
277 * solver subroutines. (This pointer is not dynamically
278 * allocated by new_scratch and free_scratch.)
280 const signed char *clues;
283 static struct solver_scratch *new_scratch(int w, int h)
285 int W = w+1, H = h+1;
286 struct solver_scratch *ret = snew(struct solver_scratch);
287 ret->connected = snewn(W*H, int);
288 ret->exits = snewn(W*H, int);
289 ret->border = snewn(W*H, unsigned char);
290 ret->equiv = snewn(w*h, int);
291 ret->slashval = snewn(w*h, signed char);
295 static void free_scratch(struct solver_scratch *sc)
301 sfree(sc->connected);
306 * Wrapper on dsf_merge() which updates the `exits' and `border'
309 static void merge_vertices(int *connected,
310 struct solver_scratch *sc, int i, int j)
312 int exits = -1, border = FALSE; /* initialise to placate optimiser */
315 i = dsf_canonify(connected, i);
316 j = dsf_canonify(connected, j);
319 * We have used one possible exit from each of the two
320 * classes. Thus, the viable exit count of the new class is
321 * the sum of the old exit counts minus two.
323 exits = sc->exits[i] + sc->exits[j] - 2;
325 border = sc->border[i] || sc->border[j];
328 dsf_merge(connected, i, j);
331 i = dsf_canonify(connected, i);
332 sc->exits[i] = exits;
333 sc->border[i] = border;
338 * Called when we have just blocked one way out of a particular
339 * point. If that point is a non-clue point (thus has a variable
340 * number of exits), we have therefore decreased its potential exit
341 * count, so we must decrement the exit count for the group as a
344 static void decr_exits(struct solver_scratch *sc, int i)
346 if (sc->clues[i] < 0) {
347 i = dsf_canonify(sc->connected, i);
352 static void fill_square(int w, int h, int x, int y, int v,
354 int *connected, struct solver_scratch *sc)
356 int W = w+1 /*, H = h+1 */;
358 assert(x >= 0 && x < w && y >= 0 && y < h);
360 if (soln[y*w+x] != 0) {
361 return; /* do nothing */
364 #ifdef SOLVER_DIAGNOSTICS
366 printf(" placing %c in %d,%d\n", v == -1 ? '\\' : '/', x, y);
372 int c = dsf_canonify(sc->equiv, y*w+x);
377 merge_vertices(connected, sc, y*W+x, (y+1)*W+(x+1));
379 decr_exits(sc, y*W+(x+1));
380 decr_exits(sc, (y+1)*W+x);
383 merge_vertices(connected, sc, y*W+(x+1), (y+1)*W+x);
385 decr_exits(sc, y*W+x);
386 decr_exits(sc, (y+1)*W+(x+1));
392 * Solver. Returns 0 for impossibility, 1 for success, 2 for
393 * ambiguity or failure to converge.
395 static int slant_solve(int w, int h, const signed char *clues,
396 signed char *soln, struct solver_scratch *sc,
399 int W = w+1, H = h+1;
406 memset(soln, 0, w*h);
411 * Establish a disjoint set forest for tracking connectedness
412 * between grid points.
414 for (i = 0; i < W*H; i++)
415 sc->connected[i] = i; /* initially all distinct */
418 * Establish a disjoint set forest for tracking which squares
419 * are known to slant in the same direction.
421 for (i = 0; i < w*h; i++)
422 sc->equiv[i] = i; /* initially all distinct */
425 * Clear the slashval array.
427 memset(sc->slashval, 0, w*h);
430 * Initialise the `exits' and `border' arrays. Theses is used
431 * to do second-order loop avoidance: the dual of the no loops
432 * constraint is that every point must be somehow connected to
433 * the border of the grid (otherwise there would be a solid
434 * loop around it which prevented this).
436 * I define a `dead end' to be a connected group of points
437 * which contains no border point, and which can form at most
438 * one new connection outside itself. Then I forbid placing an
439 * edge so that it connects together two dead-end groups, since
440 * this would yield a non-border-connected isolated subgraph
441 * with no further scope to extend it.
443 for (y = 0; y < H; y++)
444 for (x = 0; x < W; x++) {
445 if (y == 0 || y == H-1 || x == 0 || x == W-1)
446 sc->border[y*W+x] = TRUE;
448 sc->border[y*W+x] = FALSE;
450 if (clues[y*W+x] < 0)
451 sc->exits[y*W+x] = 4;
453 sc->exits[y*W+x] = clues[y*W+x];
457 * Make a one-off preliminary pass over the grid looking for
458 * starting-point arrangements. The ones we need to spot are:
460 * - two adjacent 1s in the centre of the grid imply that each
461 * one's single line points towards the other. (If either 1
462 * were connected on the far side, the two squares shared
463 * between the 1s would both link to the other 1 as a
464 * consequence of neither linking to the first.) Thus, we
465 * can fill in the four squares around them.
467 * - dually, two adjacent 3s imply that each one's _non_-line
468 * points towards the other.
470 * - if the pair of 1s and 3s is not _adjacent_ but is
471 * separated by one or more 2s, the reasoning still applies.
473 * This is more advanced than just spotting obvious starting
474 * squares such as central 4s and edge 2s, so we disable it on
477 * (I don't like this loop; it feels grubby to me. My
478 * mathematical intuition feels there ought to be some more
479 * general deductive form which contains this loop as a special
480 * case, but I can't bring it to mind right now.)
482 if (difficulty > DIFF_EASY) {
483 for (y = 1; y+1 < H; y++)
484 for (x = 1; x+1 < W; x++) {
485 int v = clues[y*W+x], s, x2, y2, dx, dy;
486 if (v != 1 && v != 3)
488 /* Slash value of the square up and left of (x,y). */
489 s = (v == 1 ? +1 : -1);
491 /* Look in each direction once. */
492 for (dy = 0; dy < 2; dy++) {
496 if (x2+1 >= W || y2+1 >= H)
497 continue; /* too close to the border */
498 while (x2+dx+1 < W && y2+dy+1 < H && clues[y2*W+x2] == 2)
500 if (clues[y2*W+x2] == v) {
501 #ifdef SOLVER_DIAGNOSTICS
503 printf("found adjacent %ds at %d,%d and %d,%d\n",
506 fill_square(w, h, x-1, y-1, s, soln,
508 fill_square(w, h, x-1+dy, y-1+dx, -s, soln,
510 fill_square(w, h, x2, y2, s, soln,
512 fill_square(w, h, x2-dy, y2-dx, -s, soln,
520 * Repeatedly try to deduce something until we can't.
523 done_something = FALSE;
526 * Any clue point with the number of remaining lines equal
527 * to zero or to the number of remaining undecided
528 * neighbouring squares can be filled in completely.
530 for (y = 0; y < H; y++)
531 for (x = 0; x < W; x++) {
536 int nu, nl, c, s, eq, eq2, last, meq, mj1, mj2;
538 if ((c = clues[y*W+x]) < 0)
542 * We have a clue point. Start by listing its
543 * neighbouring squares, in order around the point,
544 * together with the type of slash that would be
545 * required in that square to connect to the point.
548 if (x > 0 && y > 0) {
549 neighbours[nneighbours].pos = (y-1)*w+(x-1);
550 neighbours[nneighbours].slash = -1;
553 if (x > 0 && y < h) {
554 neighbours[nneighbours].pos = y*w+(x-1);
555 neighbours[nneighbours].slash = +1;
558 if (x < w && y < h) {
559 neighbours[nneighbours].pos = y*w+x;
560 neighbours[nneighbours].slash = -1;
563 if (x < w && y > 0) {
564 neighbours[nneighbours].pos = (y-1)*w+x;
565 neighbours[nneighbours].slash = +1;
570 * Count up the number of undecided neighbours, and
571 * also the number of lines already present.
573 * If we're not on DIFF_EASY, then in this loop we
574 * also track whether we've seen two adjacent empty
575 * squares belonging to the same equivalence class
576 * (meaning they have the same type of slash). If
577 * so, we count them jointly as one line.
581 last = neighbours[nneighbours-1].pos;
583 eq = dsf_canonify(sc->equiv, last);
586 meq = mj1 = mj2 = -1;
587 for (i = 0; i < nneighbours; i++) {
588 j = neighbours[i].pos;
589 s = neighbours[i].slash;
591 nu++; /* undecided */
592 if (meq < 0 && difficulty > DIFF_EASY) {
593 eq2 = dsf_canonify(sc->equiv, j);
594 if (eq == eq2 && last != j) {
596 * We've found an equivalent pair.
597 * Mark it. This also inhibits any
598 * further equivalence tracking
599 * around this square, since we can
600 * only handle one pair (and in
601 * particular we want to avoid
602 * being misled by two overlapping
603 * equivalence pairs).
608 nl--; /* count one line */
609 nu -= 2; /* and lose two undecideds */
616 nl--; /* here's a line */
624 if (nl < 0 || nl > nu) {
626 * No consistent value for this at all!
628 #ifdef SOLVER_DIAGNOSTICS
630 printf("need %d / %d lines around clue point at %d,%d!\n",
633 return 0; /* impossible */
636 if (nu > 0 && (nl == 0 || nl == nu)) {
637 #ifdef SOLVER_DIAGNOSTICS
640 printf("partially (since %d,%d == %d,%d) ",
641 mj1%w, mj1/w, mj2%w, mj2/w);
642 printf("%s around clue point at %d,%d\n",
643 nl ? "filling" : "emptying", x, y);
646 for (i = 0; i < nneighbours; i++) {
647 j = neighbours[i].pos;
648 s = neighbours[i].slash;
649 if (soln[j] == 0 && j != mj1 && j != mj2)
650 fill_square(w, h, j%w, j/w, (nl ? s : -s), soln,
654 done_something = TRUE;
655 } else if (nu == 2 && nl == 1 && difficulty > DIFF_EASY) {
657 * If we have precisely two undecided squares
658 * and precisely one line to place between
659 * them, _and_ those squares are adjacent, then
660 * we can mark them as equivalent to one
663 * This even applies if meq >= 0: if we have a
664 * 2 clue point and two of its neighbours are
665 * already marked equivalent, we can indeed
666 * mark the other two as equivalent.
668 * We don't bother with this on DIFF_EASY,
669 * since we wouldn't have used the results
673 for (i = 0; i < nneighbours; i++) {
674 j = neighbours[i].pos;
675 if (soln[j] == 0 && j != mj1 && j != mj2) {
678 else if (last == i-1 || (last == 0 && i == 3))
679 break; /* found a pair */
682 if (i < nneighbours) {
687 * neighbours[last] and neighbours[i] are
688 * the pair. Mark them equivalent.
690 #ifdef SOLVER_DIAGNOSTICS
693 printf("since %d,%d == %d,%d, ",
694 mj1%w, mj1/w, mj2%w, mj2/w);
697 mj1 = neighbours[last].pos;
698 mj2 = neighbours[i].pos;
699 #ifdef SOLVER_DIAGNOSTICS
701 printf("clue point at %d,%d implies %d,%d == %d,"
702 "%d\n", x, y, mj1%w, mj1/w, mj2%w, mj2/w);
704 mj1 = dsf_canonify(sc->equiv, mj1);
705 sv1 = sc->slashval[mj1];
706 mj2 = dsf_canonify(sc->equiv, mj2);
707 sv2 = sc->slashval[mj2];
708 if (sv1 != 0 && sv2 != 0 && sv1 != sv2) {
709 #ifdef SOLVER_DIAGNOSTICS
711 printf("merged two equivalence classes with"
712 " different slash values!\n");
716 sv1 = sv1 ? sv1 : sv2;
717 dsf_merge(sc->equiv, mj1, mj2);
718 mj1 = dsf_canonify(sc->equiv, mj1);
719 sc->slashval[mj1] = sv1;
728 * Failing that, we now apply the second condition, which
729 * is that no square may be filled in such a way as to form
730 * a loop. Also in this loop (since it's over squares
731 * rather than points), we check slashval to see if we've
732 * already filled in another square in the same equivalence
735 * The slashval check is disabled on DIFF_EASY, as is dead
736 * end avoidance. Only _immediate_ loop avoidance remains.
738 for (y = 0; y < h; y++)
739 for (x = 0; x < w; x++) {
742 #ifdef SOLVER_DIAGNOSTICS
743 char *reason = "<internal error>";
747 continue; /* got this one already */
752 if (difficulty > DIFF_EASY)
753 v = sc->slashval[dsf_canonify(sc->equiv, y*w+x)];
758 * Try to rule out connectivity between (x,y) and
759 * (x+1,y+1); if successful, we will deduce that we
760 * must have a forward slash.
762 c1 = dsf_canonify(sc->connected, y*W+x);
763 c2 = dsf_canonify(sc->connected, (y+1)*W+(x+1));
766 #ifdef SOLVER_DIAGNOSTICS
767 reason = "simple loop avoidance";
770 if (difficulty > DIFF_EASY &&
771 !sc->border[c1] && !sc->border[c2] &&
772 sc->exits[c1] <= 1 && sc->exits[c2] <= 1) {
774 #ifdef SOLVER_DIAGNOSTICS
775 reason = "dead end avoidance";
780 #ifdef SOLVER_DIAGNOSTICS
781 reason = "equivalence to an already filled square";
786 * Now do the same between (x+1,y) and (x,y+1), to
787 * see if we are required to have a backslash.
789 c1 = dsf_canonify(sc->connected, y*W+(x+1));
790 c2 = dsf_canonify(sc->connected, (y+1)*W+x);
793 #ifdef SOLVER_DIAGNOSTICS
794 reason = "simple loop avoidance";
797 if (difficulty > DIFF_EASY &&
798 !sc->border[c1] && !sc->border[c2] &&
799 sc->exits[c1] <= 1 && sc->exits[c2] <= 1) {
801 #ifdef SOLVER_DIAGNOSTICS
802 reason = "dead end avoidance";
807 #ifdef SOLVER_DIAGNOSTICS
808 reason = "equivalence to an already filled square";
814 * No consistent value for this at all!
816 #ifdef SOLVER_DIAGNOSTICS
818 printf("%d,%d has no consistent slash!\n", x, y);
820 return 0; /* impossible */
824 #ifdef SOLVER_DIAGNOSTICS
826 printf("employing %s\n", reason);
828 fill_square(w, h, x, y, +1, soln, sc->connected, sc);
829 done_something = TRUE;
831 #ifdef SOLVER_DIAGNOSTICS
833 printf("employing %s\n", reason);
835 fill_square(w, h, x, y, -1, soln, sc->connected, sc);
836 done_something = TRUE;
840 } while (done_something);
843 * Solver can make no more progress. See if the grid is full.
845 for (i = 0; i < w*h; i++)
847 return 2; /* failed to converge */
848 return 1; /* success */
852 * Filled-grid generator.
854 static void slant_generate(int w, int h, signed char *soln, random_state *rs)
856 int W = w+1, H = h+1;
858 int *connected, *indices;
863 memset(soln, 0, w*h);
866 * Establish a disjoint set forest for tracking connectedness
867 * between grid points.
869 connected = snewn(W*H, int);
870 for (i = 0; i < W*H; i++)
871 connected[i] = i; /* initially all distinct */
874 * Prepare a list of the squares in the grid, and fill them in
877 indices = snewn(w*h, int);
878 for (i = 0; i < w*h; i++)
880 shuffle(indices, w*h, sizeof(*indices), rs);
883 * Fill in each one in turn.
885 for (i = 0; i < w*h; i++) {
891 fs = (dsf_canonify(connected, y*W+x) ==
892 dsf_canonify(connected, (y+1)*W+(x+1)));
893 bs = (dsf_canonify(connected, (y+1)*W+x) ==
894 dsf_canonify(connected, y*W+(x+1)));
897 * It isn't possible to get into a situation where we
898 * aren't allowed to place _either_ type of slash in a
899 * square. Thus, filled-grid generation never has to
902 * Proof (thanks to Gareth Taylor):
904 * If it were possible, it would have to be because there
905 * was an existing path (not using this square) between the
906 * top-left and bottom-right corners of this square, and
907 * another between the other two. These two paths would
908 * have to cross at some point.
910 * Obviously they can't cross in the middle of a square, so
911 * they must cross by sharing a point in common. But this
912 * isn't possible either: if you chessboard-colour all the
913 * points on the grid, you find that any continuous
914 * diagonal path is entirely composed of points of the same
915 * colour. And one of our two hypothetical paths is between
916 * two black points, and the other is between two white
917 * points - therefore they can have no point in common. []
921 v = fs ? +1 : bs ? -1 : 2 * random_upto(rs, 2) - 1;
922 fill_square(w, h, x, y, v, soln, connected, NULL);
929 static char *new_game_desc(game_params *params, random_state *rs,
930 char **aux, int interactive)
932 int w = params->w, h = params->h, W = w+1, H = h+1;
933 signed char *soln, *tmpsoln, *clues;
935 struct solver_scratch *sc;
939 soln = snewn(w*h, signed char);
940 tmpsoln = snewn(w*h, signed char);
941 clues = snewn(W*H, signed char);
942 clueindices = snewn(W*H, int);
943 sc = new_scratch(w, h);
947 * Create the filled grid.
949 slant_generate(w, h, soln, rs);
952 * Fill in the complete set of clues.
954 for (y = 0; y < H; y++)
955 for (x = 0; x < W; x++) {
958 if (x > 0 && y > 0 && soln[(y-1)*w+(x-1)] == -1) v++;
959 if (x > 0 && y < h && soln[y*w+(x-1)] == +1) v++;
960 if (x < w && y > 0 && soln[(y-1)*w+x] == +1) v++;
961 if (x < w && y < h && soln[y*w+x] == -1) v++;
967 * With all clue points filled in, all puzzles are easy: we can
968 * simply process the clue points in lexicographic order, and
969 * at each clue point we will always have at most one square
970 * undecided, which we can then fill in uniquely.
972 assert(slant_solve(w, h, clues, tmpsoln, sc, DIFF_EASY) == 1);
975 * Remove as many clues as possible while retaining solubility.
977 * In DIFF_HARD mode, we prioritise the removal of obvious
978 * starting points (4s, 0s, border 2s and corner 1s), on
979 * the grounds that having as few of these as possible
980 * seems like a good thing. In particular, we can often get
981 * away without _any_ completely obvious starting points,
982 * which is even better.
984 for (i = 0; i < W*H; i++)
986 shuffle(clueindices, W*H, sizeof(*clueindices), rs);
987 for (j = 0; j < 2; j++) {
988 for (i = 0; i < W*H; i++) {
991 y = clueindices[i] / W;
992 x = clueindices[i] % W;
996 * Identify which pass we should process this point
997 * in. If it's an obvious start point, _or_ we're
998 * in DIFF_EASY, then it goes in pass 0; otherwise
1001 xb = (x == 0 || x == W-1);
1002 yb = (y == 0 || y == H-1);
1003 if (params->diff == DIFF_EASY || v == 4 || v == 0 ||
1004 (v == 2 && (xb||yb)) || (v == 1 && xb && yb))
1011 if (slant_solve(w, h, clues, tmpsoln, sc,
1013 clues[y*W+x] = v; /* put it back */
1019 * And finally, verify that the grid is of _at least_ the
1020 * requested difficulty, by running the solver one level
1021 * down and verifying that it can't manage it.
1023 } while (params->diff > 0 &&
1024 slant_solve(w, h, clues, tmpsoln, sc, params->diff - 1) <= 1);
1027 * Now we have the clue set as it will be presented to the
1028 * user. Encode it in a game desc.
1034 desc = snewn(W*H+1, char);
1037 for (i = 0; i <= W*H; i++) {
1038 int n = (i < W*H ? clues[i] : -2);
1045 int c = 'a' - 1 + run;
1049 run -= c - ('a' - 1);
1057 assert(p - desc <= W*H);
1059 desc = sresize(desc, p - desc, char);
1063 * Encode the solution as an aux_info.
1067 *aux = auxbuf = snewn(w*h+1, char);
1068 for (i = 0; i < w*h; i++)
1069 auxbuf[i] = soln[i] < 0 ? '\\' : '/';
1082 static char *validate_desc(game_params *params, char *desc)
1084 int w = params->w, h = params->h, W = w+1, H = h+1;
1090 if (n >= 'a' && n <= 'z') {
1091 squares += n - 'a' + 1;
1092 } else if (n >= '0' && n <= '4') {
1095 return "Invalid character in game description";
1099 return "Not enough data to fill grid";
1102 return "Too much data to fit in grid";
1107 static game_state *new_game(midend *me, game_params *params, char *desc)
1109 int w = params->w, h = params->h, W = w+1, H = h+1;
1110 game_state *state = snew(game_state);
1115 state->soln = snewn(w*h, signed char);
1116 memset(state->soln, 0, w*h);
1117 state->completed = state->used_solve = FALSE;
1118 state->errors = snewn(W*H, unsigned char);
1119 memset(state->errors, 0, W*H);
1121 state->clues = snew(game_clues);
1122 state->clues->w = w;
1123 state->clues->h = h;
1124 state->clues->clues = snewn(W*H, signed char);
1125 state->clues->refcount = 1;
1126 state->clues->tmpdsf = snewn(W*H, int);
1127 memset(state->clues->clues, -1, W*H);
1130 if (n >= 'a' && n <= 'z') {
1131 squares += n - 'a' + 1;
1132 } else if (n >= '0' && n <= '4') {
1133 state->clues->clues[squares++] = n - '0';
1135 assert(!"can't get here");
1137 assert(squares == area);
1142 static game_state *dup_game(game_state *state)
1144 int w = state->p.w, h = state->p.h, W = w+1, H = h+1;
1145 game_state *ret = snew(game_state);
1148 ret->clues = state->clues;
1149 ret->clues->refcount++;
1150 ret->completed = state->completed;
1151 ret->used_solve = state->used_solve;
1153 ret->soln = snewn(w*h, signed char);
1154 memcpy(ret->soln, state->soln, w*h);
1156 ret->errors = snewn(W*H, unsigned char);
1157 memcpy(ret->errors, state->errors, W*H);
1162 static void free_game(game_state *state)
1164 sfree(state->errors);
1166 assert(state->clues);
1167 if (--state->clues->refcount <= 0) {
1168 sfree(state->clues->clues);
1169 sfree(state->clues->tmpdsf);
1170 sfree(state->clues);
1176 * Utility function to return the current degree of a vertex. If
1177 * `anti' is set, it returns the number of filled-in edges
1178 * surrounding the point which _don't_ connect to it; thus 4 minus
1179 * its anti-degree is the maximum degree it could have if all the
1180 * empty spaces around it were filled in.
1182 * (Yes, _4_ minus its anti-degree even if it's a border vertex.)
1184 * If ret > 0, *sx and *sy are set to the coordinates of one of the
1185 * squares that contributed to it.
1187 static int vertex_degree(int w, int h, signed char *soln, int x, int y,
1188 int anti, int *sx, int *sy)
1192 assert(x >= 0 && x <= w && y >= 0 && y <= h);
1193 if (x > 0 && y > 0 && soln[(y-1)*w+(x-1)] - anti < 0) {
1198 if (x > 0 && y < h && soln[y*w+(x-1)] + anti > 0) {
1203 if (x < w && y > 0 && soln[(y-1)*w+x] + anti > 0) {
1208 if (x < w && y < h && soln[y*w+x] - anti < 0) {
1214 return anti ? 4 - ret : ret;
1217 static int check_completion(game_state *state)
1219 int w = state->p.w, h = state->p.h, W = w+1, H = h+1;
1220 int i, x, y, err = FALSE;
1223 memset(state->errors, 0, W*H);
1226 * To detect loops in the grid, we iterate through each edge
1227 * building up a dsf of connected components, and raise the
1228 * alarm whenever we find an edge that connects two
1229 * already-connected vertices.
1231 * We use the `tmpdsf' scratch space in the shared clues
1232 * structure, to avoid mallocing too often.
1234 * When we find such an edge, we then search around the grid to
1235 * find the loop it is a part of, so that we can highlight it
1236 * as an error for the user. We do this by the hand-on-one-wall
1237 * technique: the search will follow branches off the inside of
1238 * the loop, discover they're dead ends, and unhighlight them
1239 * again when returning to the actual loop.
1241 * This technique guarantees that every loop it tracks will
1242 * surround a disjoint area of the grid (since if an existing
1243 * loop appears on the boundary of a new one, so that there are
1244 * multiple possible paths that would come back to the starting
1245 * point, it will pick the one that allows it to turn right
1246 * most sharply and hence the one that does not re-surround the
1247 * area of the previous one). Thus, the total time taken in
1248 * searching round loops is linear in the grid area since every
1249 * edge is visited at most twice.
1251 dsf = state->clues->tmpdsf;
1252 for (i = 0; i < W*H; i++)
1253 dsf[i] = i; /* initially all distinct */
1254 for (y = 0; y < h; y++)
1255 for (x = 0; x < w; x++) {
1258 if (state->soln[y*w+x] == 0)
1260 if (state->soln[y*w+x] < 0) {
1269 * Our edge connects i1 with i2. If they're already
1270 * connected, flag an error. Otherwise, link them.
1272 if (dsf_canonify(dsf, i1) == dsf_canonify(dsf, i2)) {
1273 int x1, y1, x2, y2, dx, dy, dt, pass;
1278 * Now search around the boundary of the loop to
1281 * We have to do this in two passes. The first
1282 * time, we toggle ERR_SQUARE_TMP on each edge;
1283 * this pass terminates with ERR_SQUARE_TMP set on
1284 * exactly the loop edges. In the second pass, we
1285 * trace round that loop again and turn
1286 * ERR_SQUARE_TMP into ERR_SQUARE. We have to do
1287 * this because otherwise we might cancel part of a
1288 * loop highlighted in a previous iteration of the
1292 for (pass = 0; pass < 2; pass++) {
1300 /* Mark this edge. */
1302 state->errors[min(y1,y2)*W+min(x1,x2)] ^=
1305 state->errors[min(y1,y2)*W+min(x1,x2)] |=
1307 state->errors[min(y1,y2)*W+min(x1,x2)] &=
1312 * Progress to the next edge by turning as
1313 * sharply right as possible. In fact we do
1314 * this by facing back along the edge and
1315 * turning _left_ until we see an edge we
1321 for (i = 0; i < 4; i++) {
1323 * Rotate (dx,dy) to the left.
1325 dt = dx; dx = dy; dy = -dt;
1328 * See if (x2,y2) has an edge in direction
1331 if (x2+dx < 0 || x2+dx >= W ||
1332 y2+dy < 0 || y2+dy >= H)
1333 continue; /* off the side of the grid */
1334 /* In the second pass, ignore unmarked edges. */
1336 !(state->errors[(y2-(dy<0))*W+x2-(dx<0)] &
1339 if (state->soln[(y2-(dy<0))*w+x2-(dx<0)] ==
1345 * In pass 0, we expect to have found
1346 * _some_ edge we can follow, even if it
1347 * was found by rotating all the way round
1348 * and going back the way we came.
1350 * In pass 1, because we're removing the
1351 * mark on each edge that allows us to
1352 * follow it, we expect to find _no_ edge
1353 * we can follow when we've come all the
1354 * way round the loop.
1356 if (pass == 1 && i == 4)
1361 * Set x1,y1 to x2,y2, and x2,y2 to be the
1362 * other end of the new edge.
1368 } while (y2*W+x2 != i2);
1373 dsf_merge(dsf, i1, i2);
1377 * Now go through and check the degree of each clue vertex, and
1378 * mark it with ERR_VERTEX if it cannot be fulfilled.
1380 for (y = 0; y < H; y++)
1381 for (x = 0; x < W; x++) {
1384 if ((c = state->clues->clues[y*W+x]) < 0)
1388 * Check to see if there are too many connections to
1389 * this vertex _or_ too many non-connections. Either is
1390 * grounds for marking the vertex as erroneous.
1392 if (vertex_degree(w, h, state->soln, x, y,
1393 FALSE, NULL, NULL) > c ||
1394 vertex_degree(w, h, state->soln, x, y,
1395 TRUE, NULL, NULL) > 4-c) {
1396 state->errors[y*W+x] |= ERR_VERTEX;
1402 * Now our actual victory condition is that (a) none of the
1403 * above code marked anything as erroneous, and (b) every
1404 * square has an edge in it.
1410 for (y = 0; y < h; y++)
1411 for (x = 0; x < w; x++)
1412 if (state->soln[y*w+x] == 0)
1418 static char *solve_game(game_state *state, game_state *currstate,
1419 char *aux, char **error)
1421 int w = state->p.w, h = state->p.h;
1424 int free_soln = FALSE;
1425 char *move, buf[80];
1426 int movelen, movesize;
1431 * If we already have the solution, save ourselves some
1434 soln = (signed char *)aux;
1435 bs = (signed char)'\\';
1438 struct solver_scratch *sc = new_scratch(w, h);
1439 soln = snewn(w*h, signed char);
1441 ret = slant_solve(w, h, state->clues->clues, soln, sc, DIFF_HARD);
1446 *error = "This puzzle is not self-consistent";
1448 *error = "Unable to find a unique solution for this puzzle";
1455 * Construct a move string which turns the current state into
1459 move = snewn(movesize, char);
1461 move[movelen++] = 'S';
1462 move[movelen] = '\0';
1463 for (y = 0; y < h; y++)
1464 for (x = 0; x < w; x++) {
1465 int v = (soln[y*w+x] == bs ? -1 : +1);
1466 if (state->soln[y*w+x] != v) {
1467 int len = sprintf(buf, ";%c%d,%d", (int)(v < 0 ? '\\' : '/'), x, y);
1468 if (movelen + len >= movesize) {
1469 movesize = movelen + len + 256;
1470 move = sresize(move, movesize, char);
1472 strcpy(move + movelen, buf);
1483 static char *game_text_format(game_state *state)
1485 int w = state->p.w, h = state->p.h, W = w+1, H = h+1;
1490 * There are h+H rows of w+W columns.
1492 len = (h+H) * (w+W+1) + 1;
1493 ret = snewn(len, char);
1496 for (y = 0; y < H; y++) {
1497 for (x = 0; x < W; x++) {
1498 if (state->clues->clues[y*W+x] >= 0)
1499 *p++ = state->clues->clues[y*W+x] + '0';
1507 for (x = 0; x < W; x++) {
1510 if (state->soln[y*w+x] != 0)
1511 *p++ = (state->soln[y*w+x] < 0 ? '\\' : '/');
1521 assert(p - ret == len);
1525 static game_ui *new_ui(game_state *state)
1530 static void free_ui(game_ui *ui)
1534 static char *encode_ui(game_ui *ui)
1539 static void decode_ui(game_ui *ui, char *encoding)
1543 static void game_changed_state(game_ui *ui, game_state *oldstate,
1544 game_state *newstate)
1548 #define PREFERRED_TILESIZE 32
1549 #define TILESIZE (ds->tilesize)
1550 #define BORDER TILESIZE
1551 #define CLUE_RADIUS (TILESIZE / 3)
1552 #define CLUE_TEXTSIZE (TILESIZE / 2)
1553 #define COORD(x) ( (x) * TILESIZE + BORDER )
1554 #define FROMCOORD(x) ( ((x) - BORDER + TILESIZE) / TILESIZE - 1 )
1556 #define FLASH_TIME 0.30F
1559 * Bit fields in the `grid' and `todraw' elements of the drawstate.
1561 #define BACKSLASH 0x00000001L
1562 #define FORWSLASH 0x00000002L
1563 #define L_T 0x00000004L
1564 #define ERR_L_T 0x00000008L
1565 #define L_B 0x00000010L
1566 #define ERR_L_B 0x00000020L
1567 #define T_L 0x00000040L
1568 #define ERR_T_L 0x00000080L
1569 #define T_R 0x00000100L
1570 #define ERR_T_R 0x00000200L
1571 #define C_TL 0x00000400L
1572 #define ERR_C_TL 0x00000800L
1573 #define FLASH 0x00001000L
1574 #define ERRSLASH 0x00002000L
1575 #define ERR_TL 0x00004000L
1576 #define ERR_TR 0x00008000L
1577 #define ERR_BL 0x00010000L
1578 #define ERR_BR 0x00020000L
1580 struct game_drawstate {
1587 static char *interpret_move(game_state *state, game_ui *ui, game_drawstate *ds,
1588 int x, int y, int button)
1590 int w = state->p.w, h = state->p.h;
1592 if (button == LEFT_BUTTON || button == RIGHT_BUTTON) {
1597 * This is an utterly awful hack which I should really sort out
1598 * by means of a proper configuration mechanism. One Slant
1599 * player has observed that they prefer the mouse buttons to
1600 * function exactly the opposite way round, so here's a
1601 * mechanism for environment-based configuration. I cache the
1602 * result in a global variable - yuck! - to avoid repeated
1606 static int swap_buttons = -1;
1607 if (swap_buttons < 0) {
1608 char *env = getenv("SLANT_SWAP_BUTTONS");
1609 swap_buttons = (env && (env[0] == 'y' || env[0] == 'Y'));
1612 if (button == LEFT_BUTTON)
1613 button = RIGHT_BUTTON;
1615 button = LEFT_BUTTON;
1621 if (x < 0 || y < 0 || x >= w || y >= h)
1624 if (button == LEFT_BUTTON) {
1626 * Left-clicking cycles blank -> \ -> / -> blank.
1628 v = state->soln[y*w+x] - 1;
1633 * Right-clicking cycles blank -> / -> \ -> blank.
1635 v = state->soln[y*w+x] + 1;
1640 sprintf(buf, "%c%d,%d", (int)(v==-1 ? '\\' : v==+1 ? '/' : 'C'), x, y);
1647 static game_state *execute_move(game_state *state, char *move)
1649 int w = state->p.w, h = state->p.h;
1652 game_state *ret = dup_game(state);
1657 ret->used_solve = TRUE;
1659 } else if (c == '\\' || c == '/' || c == 'C') {
1661 if (sscanf(move, "%d,%d%n", &x, &y, &n) != 2 ||
1662 x < 0 || y < 0 || x >= w || y >= h) {
1666 ret->soln[y*w+x] = (c == '\\' ? -1 : c == '/' ? +1 : 0);
1681 * We never clear the `completed' flag, but we must always
1682 * re-run the completion check because it also highlights
1683 * errors in the grid.
1685 ret->completed = check_completion(ret) || ret->completed;
1690 /* ----------------------------------------------------------------------
1694 static void game_compute_size(game_params *params, int tilesize,
1697 /* fool the macros */
1698 struct dummy { int tilesize; } dummy = { tilesize }, *ds = &dummy;
1700 *x = 2 * BORDER + params->w * TILESIZE + 1;
1701 *y = 2 * BORDER + params->h * TILESIZE + 1;
1704 static void game_set_size(drawing *dr, game_drawstate *ds,
1705 game_params *params, int tilesize)
1707 ds->tilesize = tilesize;
1710 static float *game_colours(frontend *fe, game_state *state, int *ncolours)
1712 float *ret = snewn(3 * NCOLOURS, float);
1714 frontend_default_colour(fe, &ret[COL_BACKGROUND * 3]);
1716 ret[COL_GRID * 3 + 0] = ret[COL_BACKGROUND * 3 + 0] * 0.7F;
1717 ret[COL_GRID * 3 + 1] = ret[COL_BACKGROUND * 3 + 1] * 0.7F;
1718 ret[COL_GRID * 3 + 2] = ret[COL_BACKGROUND * 3 + 2] * 0.7F;
1720 ret[COL_INK * 3 + 0] = 0.0F;
1721 ret[COL_INK * 3 + 1] = 0.0F;
1722 ret[COL_INK * 3 + 2] = 0.0F;
1724 ret[COL_SLANT1 * 3 + 0] = 0.0F;
1725 ret[COL_SLANT1 * 3 + 1] = 0.0F;
1726 ret[COL_SLANT1 * 3 + 2] = 0.0F;
1728 ret[COL_SLANT2 * 3 + 0] = 0.0F;
1729 ret[COL_SLANT2 * 3 + 1] = 0.0F;
1730 ret[COL_SLANT2 * 3 + 2] = 0.0F;
1732 ret[COL_ERROR * 3 + 0] = 1.0F;
1733 ret[COL_ERROR * 3 + 1] = 0.0F;
1734 ret[COL_ERROR * 3 + 2] = 0.0F;
1736 *ncolours = NCOLOURS;
1740 static game_drawstate *game_new_drawstate(drawing *dr, game_state *state)
1742 int w = state->p.w, h = state->p.h;
1744 struct game_drawstate *ds = snew(struct game_drawstate);
1747 ds->started = FALSE;
1748 ds->grid = snewn((w+2)*(h+2), long);
1749 ds->todraw = snewn((w+2)*(h+2), long);
1750 for (i = 0; i < (w+2)*(h+2); i++)
1751 ds->grid[i] = ds->todraw[i] = -1;
1756 static void game_free_drawstate(drawing *dr, game_drawstate *ds)
1763 static void draw_clue(drawing *dr, game_drawstate *ds,
1764 int x, int y, long v, long err, int bg, int colour)
1767 int ccol = colour >= 0 ? colour : ((x ^ y) & 1) ? COL_SLANT1 : COL_SLANT2;
1768 int tcol = colour >= 0 ? colour : err ? COL_ERROR : COL_INK;
1775 draw_circle(dr, COORD(x), COORD(y), CLUE_RADIUS,
1776 bg >= 0 ? bg : COL_BACKGROUND, ccol);
1777 draw_text(dr, COORD(x), COORD(y), FONT_VARIABLE,
1778 CLUE_TEXTSIZE, ALIGN_VCENTRE|ALIGN_HCENTRE, tcol, p);
1781 static void draw_tile(drawing *dr, game_drawstate *ds, game_clues *clues,
1782 int x, int y, long v)
1784 int w = clues->w, h = clues->h, W = w+1 /*, H = h+1 */;
1785 int chesscolour = (x ^ y) & 1;
1786 int fscol = chesscolour ? COL_SLANT2 : COL_SLANT1;
1787 int bscol = chesscolour ? COL_SLANT1 : COL_SLANT2;
1789 clip(dr, COORD(x), COORD(y), TILESIZE, TILESIZE);
1791 draw_rect(dr, COORD(x), COORD(y), TILESIZE, TILESIZE,
1792 (v & FLASH) ? COL_GRID : COL_BACKGROUND);
1795 * Draw the grid lines.
1797 if (x >= 0 && x < w && y >= 0)
1798 draw_rect(dr, COORD(x), COORD(y), TILESIZE+1, 1, COL_GRID);
1799 if (x >= 0 && x < w && y < h)
1800 draw_rect(dr, COORD(x), COORD(y+1), TILESIZE+1, 1, COL_GRID);
1801 if (y >= 0 && y < h && x >= 0)
1802 draw_rect(dr, COORD(x), COORD(y), 1, TILESIZE+1, COL_GRID);
1803 if (y >= 0 && y < h && x < w)
1804 draw_rect(dr, COORD(x+1), COORD(y), 1, TILESIZE+1, COL_GRID);
1805 if (x == -1 && y == -1)
1806 draw_rect(dr, COORD(x+1), COORD(y+1), 1, 1, COL_GRID);
1807 if (x == -1 && y == h)
1808 draw_rect(dr, COORD(x+1), COORD(y), 1, 1, COL_GRID);
1809 if (x == w && y == -1)
1810 draw_rect(dr, COORD(x), COORD(y+1), 1, 1, COL_GRID);
1811 if (x == w && y == h)
1812 draw_rect(dr, COORD(x), COORD(y), 1, 1, COL_GRID);
1817 if (v & BACKSLASH) {
1818 int scol = (v & ERRSLASH) ? COL_ERROR : bscol;
1819 draw_line(dr, COORD(x), COORD(y), COORD(x+1), COORD(y+1), scol);
1820 draw_line(dr, COORD(x)+1, COORD(y), COORD(x+1), COORD(y+1)-1,
1822 draw_line(dr, COORD(x), COORD(y)+1, COORD(x+1)-1, COORD(y+1),
1824 } else if (v & FORWSLASH) {
1825 int scol = (v & ERRSLASH) ? COL_ERROR : fscol;
1826 draw_line(dr, COORD(x+1), COORD(y), COORD(x), COORD(y+1), scol);
1827 draw_line(dr, COORD(x+1)-1, COORD(y), COORD(x), COORD(y+1)-1,
1829 draw_line(dr, COORD(x+1), COORD(y)+1, COORD(x)+1, COORD(y+1),
1834 * Draw dots on the grid corners that appear if a slash is in a
1835 * neighbouring cell.
1837 if (v & (L_T | BACKSLASH))
1838 draw_rect(dr, COORD(x), COORD(y)+1, 1, 1,
1839 (v & ERR_L_T ? COL_ERROR : bscol));
1840 if (v & (L_B | FORWSLASH))
1841 draw_rect(dr, COORD(x), COORD(y+1)-1, 1, 1,
1842 (v & ERR_L_B ? COL_ERROR : fscol));
1843 if (v & (T_L | BACKSLASH))
1844 draw_rect(dr, COORD(x)+1, COORD(y), 1, 1,
1845 (v & ERR_T_L ? COL_ERROR : bscol));
1846 if (v & (T_R | FORWSLASH))
1847 draw_rect(dr, COORD(x+1)-1, COORD(y), 1, 1,
1848 (v & ERR_T_R ? COL_ERROR : fscol));
1849 if (v & (C_TL | BACKSLASH))
1850 draw_rect(dr, COORD(x), COORD(y), 1, 1,
1851 (v & ERR_C_TL ? COL_ERROR : bscol));
1854 * And finally the clues at the corners.
1856 if (x >= 0 && y >= 0)
1857 draw_clue(dr, ds, x, y, clues->clues[y*W+x], v & ERR_TL, -1, -1);
1858 if (x < w && y >= 0)
1859 draw_clue(dr, ds, x+1, y, clues->clues[y*W+(x+1)], v & ERR_TR, -1, -1);
1860 if (x >= 0 && y < h)
1861 draw_clue(dr, ds, x, y+1, clues->clues[(y+1)*W+x], v & ERR_BL, -1, -1);
1863 draw_clue(dr, ds, x+1, y+1, clues->clues[(y+1)*W+(x+1)], v & ERR_BR,
1867 draw_update(dr, COORD(x), COORD(y), TILESIZE, TILESIZE);
1870 static void game_redraw(drawing *dr, game_drawstate *ds, game_state *oldstate,
1871 game_state *state, int dir, game_ui *ui,
1872 float animtime, float flashtime)
1874 int w = state->p.w, h = state->p.h, W = w+1, H = h+1;
1879 flashing = (int)(flashtime * 3 / FLASH_TIME) != 1;
1885 game_compute_size(&state->p, TILESIZE, &ww, &wh);
1886 draw_rect(dr, 0, 0, ww, wh, COL_BACKGROUND);
1887 draw_update(dr, 0, 0, ww, wh);
1892 * Loop over the grid and work out where all the slashes are.
1893 * We need to do this because a slash in one square affects the
1894 * drawing of the next one along.
1896 for (y = -1; y <= h; y++)
1897 for (x = -1; x <= w; x++) {
1898 if (x >= 0 && x < w && y >= 0 && y < h)
1899 ds->todraw[(y+1)*(w+2)+(x+1)] = flashing ? FLASH : 0;
1901 ds->todraw[(y+1)*(w+2)+(x+1)] = 0;
1904 for (y = 0; y < h; y++) {
1905 for (x = 0; x < w; x++) {
1906 int err = state->errors[y*W+x] & ERR_SQUARE;
1908 if (state->soln[y*w+x] < 0) {
1909 ds->todraw[(y+1)*(w+2)+(x+1)] |= BACKSLASH;
1910 ds->todraw[(y+2)*(w+2)+(x+1)] |= T_R;
1911 ds->todraw[(y+1)*(w+2)+(x+2)] |= L_B;
1912 ds->todraw[(y+2)*(w+2)+(x+2)] |= C_TL;
1914 ds->todraw[(y+1)*(w+2)+(x+1)] |= ERRSLASH |
1915 ERR_T_L | ERR_L_T | ERR_C_TL;
1916 ds->todraw[(y+2)*(w+2)+(x+1)] |= ERR_T_R;
1917 ds->todraw[(y+1)*(w+2)+(x+2)] |= ERR_L_B;
1918 ds->todraw[(y+2)*(w+2)+(x+2)] |= ERR_C_TL;
1920 } else if (state->soln[y*w+x] > 0) {
1921 ds->todraw[(y+1)*(w+2)+(x+1)] |= FORWSLASH;
1922 ds->todraw[(y+1)*(w+2)+(x+2)] |= L_T | C_TL;
1923 ds->todraw[(y+2)*(w+2)+(x+1)] |= T_L | C_TL;
1925 ds->todraw[(y+1)*(w+2)+(x+1)] |= ERRSLASH |
1927 ds->todraw[(y+1)*(w+2)+(x+2)] |= ERR_L_T | ERR_C_TL;
1928 ds->todraw[(y+2)*(w+2)+(x+1)] |= ERR_T_L | ERR_C_TL;
1934 for (y = 0; y < H; y++)
1935 for (x = 0; x < W; x++)
1936 if (state->errors[y*W+x] & ERR_VERTEX) {
1937 ds->todraw[y*(w+2)+x] |= ERR_BR;
1938 ds->todraw[y*(w+2)+(x+1)] |= ERR_BL;
1939 ds->todraw[(y+1)*(w+2)+x] |= ERR_TR;
1940 ds->todraw[(y+1)*(w+2)+(x+1)] |= ERR_TL;
1944 * Now go through and draw the grid squares.
1946 for (y = -1; y <= h; y++) {
1947 for (x = -1; x <= w; x++) {
1948 if (ds->todraw[(y+1)*(w+2)+(x+1)] != ds->grid[(y+1)*(w+2)+(x+1)]) {
1949 draw_tile(dr, ds, state->clues, x, y,
1950 ds->todraw[(y+1)*(w+2)+(x+1)]);
1951 ds->grid[(y+1)*(w+2)+(x+1)] = ds->todraw[(y+1)*(w+2)+(x+1)];
1957 static float game_anim_length(game_state *oldstate, game_state *newstate,
1958 int dir, game_ui *ui)
1963 static float game_flash_length(game_state *oldstate, game_state *newstate,
1964 int dir, game_ui *ui)
1966 if (!oldstate->completed && newstate->completed &&
1967 !oldstate->used_solve && !newstate->used_solve)
1973 static int game_wants_statusbar(void)
1978 static int game_timing_state(game_state *state, game_ui *ui)
1983 static void game_print_size(game_params *params, float *x, float *y)
1988 * I'll use 6mm squares by default.
1990 game_compute_size(params, 600, &pw, &ph);
1995 static void game_print(drawing *dr, game_state *state, int tilesize)
1997 int w = state->p.w, h = state->p.h, W = w+1;
1998 int ink = print_mono_colour(dr, 0);
1999 int paper = print_mono_colour(dr, 1);
2002 /* Ick: fake up `ds->tilesize' for macro expansion purposes */
2003 game_drawstate ads, *ds = &ads;
2004 ads.tilesize = tilesize;
2009 print_line_width(dr, TILESIZE / 16);
2010 draw_rect_outline(dr, COORD(0), COORD(0), w*TILESIZE, h*TILESIZE, ink);
2015 print_line_width(dr, TILESIZE / 24);
2016 for (x = 1; x < w; x++)
2017 draw_line(dr, COORD(x), COORD(0), COORD(x), COORD(h), ink);
2018 for (y = 1; y < h; y++)
2019 draw_line(dr, COORD(0), COORD(y), COORD(w), COORD(y), ink);
2024 print_line_width(dr, TILESIZE / 12);
2025 for (y = 0; y < h; y++)
2026 for (x = 0; x < w; x++)
2027 if (state->soln[y*w+x]) {
2030 * To prevent nasty line-ending artefacts at
2031 * corners, I'll do something slightly cunning
2034 clip(dr, COORD(x), COORD(y), TILESIZE, TILESIZE);
2035 if (state->soln[y*w+x] < 0)
2039 draw_line(dr, COORD(x-1), COORD(ly), COORD(x+2), COORD(ry),
2047 print_line_width(dr, TILESIZE / 24);
2048 for (y = 0; y <= h; y++)
2049 for (x = 0; x <= w; x++)
2050 draw_clue(dr, ds, x, y, state->clues->clues[y*W+x],
2055 #define thegame slant
2058 const struct game thegame = {
2059 "Slant", "games.slant",
2066 TRUE, game_configure, custom_params,
2074 TRUE, game_text_format,
2082 PREFERRED_TILESIZE, game_compute_size, game_set_size,
2085 game_free_drawstate,
2089 TRUE, FALSE, game_print_size, game_print,
2090 game_wants_statusbar,
2091 FALSE, game_timing_state,
2092 0, /* mouse_priorities */
2095 #ifdef STANDALONE_SOLVER
2099 int main(int argc, char **argv)
2103 char *id = NULL, *desc, *err;
2105 int ret, diff, really_verbose = FALSE;
2106 struct solver_scratch *sc;
2108 while (--argc > 0) {
2110 if (!strcmp(p, "-v")) {
2111 really_verbose = TRUE;
2112 } else if (!strcmp(p, "-g")) {
2114 } else if (*p == '-') {
2115 fprintf(stderr, "%s: unrecognised option `%s'\n", argv[0], p);
2123 fprintf(stderr, "usage: %s [-g | -v] <game_id>\n", argv[0]);
2127 desc = strchr(id, ':');
2129 fprintf(stderr, "%s: game id expects a colon in it\n", argv[0]);
2134 p = default_params();
2135 decode_params(p, id);
2136 err = validate_desc(p, desc);
2138 fprintf(stderr, "%s: %s\n", argv[0], err);
2141 s = new_game(NULL, p, desc);
2143 sc = new_scratch(p->w, p->h);
2146 * When solving an Easy puzzle, we don't want to bother the
2147 * user with Hard-level deductions. For this reason, we grade
2148 * the puzzle internally before doing anything else.
2150 ret = -1; /* placate optimiser */
2151 for (diff = 0; diff < DIFFCOUNT; diff++) {
2152 ret = slant_solve(p->w, p->h, s->clues->clues,
2158 if (diff == DIFFCOUNT) {
2160 printf("Difficulty rating: harder than Hard, or ambiguous\n");
2162 printf("Unable to find a unique solution\n");
2166 printf("Difficulty rating: impossible (no solution exists)\n");
2168 printf("Difficulty rating: %s\n", slant_diffnames[diff]);
2170 verbose = really_verbose;
2171 ret = slant_solve(p->w, p->h, s->clues->clues,
2174 printf("Puzzle is inconsistent\n");
2176 fputs(game_text_format(s), stdout);