/* * slant.c: Puzzle from nikoli.co.jp involving drawing a diagonal * line through each square of a grid. */ /* * In this puzzle you have a grid of squares, each of which must * contain a diagonal line; you also have clue numbers placed at * _points_ of that grid, which means there's a (w+1) x (h+1) array * of possible clue positions. * * I'm therefore going to adopt a rigid convention throughout this * source file of using w and h for the dimensions of the grid of * squares, and W and H for the dimensions of the grid of points. * Thus, W == w+1 and H == h+1 always. * * Clue arrays will be W*H `signed char's, and the clue at each * point will be a number from 0 to 4, or -1 if there's no clue. * * Solution arrays will be W*H `signed char's, and the number at * each point will be +1 for a forward slash (/), -1 for a * backslash (\), and 0 for unknown. */ #include #include #include #include #include #include #include #include "puzzles.h" enum { COL_BACKGROUND, COL_GRID, COL_INK, COL_SLANT1, COL_SLANT2, COL_ERROR, NCOLOURS }; /* * In standalone solver mode, `verbose' is a variable which can be * set by command-line option; in debugging mode it's simply always * true. */ #if defined STANDALONE_SOLVER #define SOLVER_DIAGNOSTICS int verbose = FALSE; #elif defined SOLVER_DIAGNOSTICS #define verbose TRUE #endif /* * Difficulty levels. I do some macro ickery here to ensure that my * enum and the various forms of my name list always match up. */ #define DIFFLIST(A) \ A(EASY,Easy,e) \ A(HARD,Hard,h) #define ENUM(upper,title,lower) DIFF_ ## upper, #define TITLE(upper,title,lower) #title, #define ENCODE(upper,title,lower) #lower #define CONFIG(upper,title,lower) ":" #title enum { DIFFLIST(ENUM) DIFFCOUNT }; static char const *const slant_diffnames[] = { DIFFLIST(TITLE) }; static char const slant_diffchars[] = DIFFLIST(ENCODE); #define DIFFCONFIG DIFFLIST(CONFIG) struct game_params { int w, h, diff; }; typedef struct game_clues { int w, h; signed char *clues; int *tmpdsf; int refcount; } game_clues; #define ERR_VERTEX 1 #define ERR_SQUARE 2 #define ERR_SQUARE_TMP 4 struct game_state { struct game_params p; game_clues *clues; signed char *soln; unsigned char *errors; int completed; int used_solve; /* used to suppress completion flash */ }; static game_params *default_params(void) { game_params *ret = snew(game_params); ret->w = ret->h = 8; ret->diff = DIFF_EASY; return ret; } static const struct game_params slant_presets[] = { {5, 5, DIFF_EASY}, {5, 5, DIFF_HARD}, {8, 8, DIFF_EASY}, {8, 8, DIFF_HARD}, {12, 10, DIFF_EASY}, {12, 10, DIFF_HARD}, }; static int game_fetch_preset(int i, char **name, game_params **params) { game_params *ret; char str[80]; if (i < 0 || i >= lenof(slant_presets)) return FALSE; ret = snew(game_params); *ret = slant_presets[i]; sprintf(str, "%dx%d %s", ret->w, ret->h, slant_diffnames[ret->diff]); *name = dupstr(str); *params = ret; return TRUE; } static void free_params(game_params *params) { sfree(params); } static game_params *dup_params(game_params *params) { game_params *ret = snew(game_params); *ret = *params; /* structure copy */ return ret; } static void decode_params(game_params *ret, char const *string) { ret->w = ret->h = atoi(string); while (*string && isdigit((unsigned char)*string)) string++; if (*string == 'x') { string++; ret->h = atoi(string); while (*string && isdigit((unsigned char)*string)) string++; } if (*string == 'd') { int i; string++; for (i = 0; i < DIFFCOUNT; i++) if (*string == slant_diffchars[i]) ret->diff = i; if (*string) string++; } } static char *encode_params(game_params *params, int full) { char data[256]; sprintf(data, "%dx%d", params->w, params->h); if (full) sprintf(data + strlen(data), "d%c", slant_diffchars[params->diff]); return dupstr(data); } static config_item *game_configure(game_params *params) { config_item *ret; char buf[80]; ret = snewn(4, config_item); ret[0].name = "Width"; ret[0].type = C_STRING; sprintf(buf, "%d", params->w); ret[0].sval = dupstr(buf); ret[0].ival = 0; ret[1].name = "Height"; ret[1].type = C_STRING; sprintf(buf, "%d", params->h); ret[1].sval = dupstr(buf); ret[1].ival = 0; ret[2].name = "Difficulty"; ret[2].type = C_CHOICES; ret[2].sval = DIFFCONFIG; ret[2].ival = params->diff; ret[3].name = NULL; ret[3].type = C_END; ret[3].sval = NULL; ret[3].ival = 0; return ret; } static game_params *custom_params(config_item *cfg) { game_params *ret = snew(game_params); ret->w = atoi(cfg[0].sval); ret->h = atoi(cfg[1].sval); ret->diff = cfg[2].ival; return ret; } static char *validate_params(game_params *params, int full) { /* * (At least at the time of writing this comment) The grid * generator is actually capable of handling even zero grid * dimensions without crashing. Puzzles with a zero-area grid * are a bit boring, though, because they're already solved :-) * And puzzles with a dimension of 1 can't be made Hard, which * means the simplest thing is to forbid them altogether. */ if (params->w < 2 || params->h < 2) return "Width and height must both be at least two"; return NULL; } /* * Scratch space for solver. */ struct solver_scratch { /* * Disjoint set forest which tracks the connected sets of * points. */ int *connected; /* * Counts the number of possible exits from each connected set * of points. (That is, the number of possible _simultaneous_ * exits: an unconnected point labelled 2 has an exit count of * 2 even if all four possible edges are still under * consideration.) */ int *exits; /* * Tracks whether each connected set of points includes a * border point. */ unsigned char *border; /* * Another disjoint set forest. This one tracks _squares_ which * are known to slant in the same direction. */ int *equiv; /* * Stores slash values which we know for an equivalence class. * When we fill in a square, we set slashval[canonify(x)] to * the same value as soln[x], so that we can then spot other * squares equivalent to it and fill them in immediately via * their known equivalence. */ signed char *slashval; /* * Stores possible v-shapes. This array is w by h in size, but * not every bit of every entry is meaningful. The bits mean: * * - bit 0 for a square means that that square and the one to * its right might form a v-shape between them * - bit 1 for a square means that that square and the one to * its right might form a ^-shape between them * - bit 2 for a square means that that square and the one * below it might form a >-shape between them * - bit 3 for a square means that that square and the one * below it might form a <-shape between them * * Any starting 1 or 3 clue rules out four bits in this array * immediately; a 2 clue propagates any ruled-out bit past it * (if the two squares on one side of a 2 cannot be a v-shape, * then neither can the two on the other side be the same * v-shape); we can rule out further bits during play using * partially filled 2 clues; whenever a pair of squares is * known not to be _either_ kind of v-shape, we can mark them * as equivalent. */ unsigned char *vbitmap; /* * Useful to have this information automatically passed to * solver subroutines. (This pointer is not dynamically * allocated by new_scratch and free_scratch.) */ const signed char *clues; }; static struct solver_scratch *new_scratch(int w, int h) { int W = w+1, H = h+1; struct solver_scratch *ret = snew(struct solver_scratch); ret->connected = snewn(W*H, int); ret->exits = snewn(W*H, int); ret->border = snewn(W*H, unsigned char); ret->equiv = snewn(w*h, int); ret->slashval = snewn(w*h, signed char); ret->vbitmap = snewn(w*h, unsigned char); return ret; } static void free_scratch(struct solver_scratch *sc) { sfree(sc->vbitmap); sfree(sc->slashval); sfree(sc->equiv); sfree(sc->border); sfree(sc->exits); sfree(sc->connected); sfree(sc); } /* * Wrapper on dsf_merge() which updates the `exits' and `border' * arrays. */ static void merge_vertices(int *connected, struct solver_scratch *sc, int i, int j) { int exits = -1, border = FALSE; /* initialise to placate optimiser */ if (sc) { i = dsf_canonify(connected, i); j = dsf_canonify(connected, j); /* * We have used one possible exit from each of the two * classes. Thus, the viable exit count of the new class is * the sum of the old exit counts minus two. */ exits = sc->exits[i] + sc->exits[j] - 2; border = sc->border[i] || sc->border[j]; } dsf_merge(connected, i, j); if (sc) { i = dsf_canonify(connected, i); sc->exits[i] = exits; sc->border[i] = border; } } /* * Called when we have just blocked one way out of a particular * point. If that point is a non-clue point (thus has a variable * number of exits), we have therefore decreased its potential exit * count, so we must decrement the exit count for the group as a * whole. */ static void decr_exits(struct solver_scratch *sc, int i) { if (sc->clues[i] < 0) { i = dsf_canonify(sc->connected, i); sc->exits[i]--; } } static void fill_square(int w, int h, int x, int y, int v, signed char *soln, int *connected, struct solver_scratch *sc) { int W = w+1 /*, H = h+1 */; assert(x >= 0 && x < w && y >= 0 && y < h); if (soln[y*w+x] != 0) { return; /* do nothing */ } #ifdef SOLVER_DIAGNOSTICS if (verbose) printf(" placing %c in %d,%d\n", v == -1 ? '\\' : '/', x, y); #endif soln[y*w+x] = v; if (sc) { int c = dsf_canonify(sc->equiv, y*w+x); sc->slashval[c] = v; } if (v < 0) { merge_vertices(connected, sc, y*W+x, (y+1)*W+(x+1)); if (sc) { decr_exits(sc, y*W+(x+1)); decr_exits(sc, (y+1)*W+x); } } else { merge_vertices(connected, sc, y*W+(x+1), (y+1)*W+x); if (sc) { decr_exits(sc, y*W+x); decr_exits(sc, (y+1)*W+(x+1)); } } } static int vbitmap_clear(int w, int h, struct solver_scratch *sc, int x, int y, int vbits, char *reason, ...) { int done_something = FALSE; int vbit; for (vbit = 1; vbit <= 8; vbit <<= 1) if (vbits & sc->vbitmap[y*w+x] & vbit) { done_something = TRUE; #ifdef SOLVER_DIAGNOSTICS if (verbose) { va_list ap; printf("ruling out %c shape at (%d,%d)-(%d,%d) (", "!v^!>!!!<"[vbit], x, y, x+((vbit&0x3)!=0), y+((vbit&0xC)!=0)); va_start(ap, reason); vprintf(reason, ap); va_end(ap); printf(")\n"); } #endif sc->vbitmap[y*w+x] &= ~vbit; } return done_something; } /* * Solver. Returns 0 for impossibility, 1 for success, 2 for * ambiguity or failure to converge. */ static int slant_solve(int w, int h, const signed char *clues, signed char *soln, struct solver_scratch *sc, int difficulty) { int W = w+1, H = h+1; int x, y, i, j; int done_something; /* * Clear the output. */ memset(soln, 0, w*h); sc->clues = clues; /* * Establish a disjoint set forest for tracking connectedness * between grid points. */ dsf_init(sc->connected, W*H); /* * Establish a disjoint set forest for tracking which squares * are known to slant in the same direction. */ dsf_init(sc->equiv, w*h); /* * Clear the slashval array. */ memset(sc->slashval, 0, w*h); /* * Set up the vbitmap array. Initially all types of v are possible. */ memset(sc->vbitmap, 0xF, w*h); /* * Initialise the `exits' and `border' arrays. These are used * to do second-order loop avoidance: the dual of the no loops * constraint is that every point must be somehow connected to * the border of the grid (otherwise there would be a solid * loop around it which prevented this). * * I define a `dead end' to be a connected group of points * which contains no border point, and which can form at most * one new connection outside itself. Then I forbid placing an * edge so that it connects together two dead-end groups, since * this would yield a non-border-connected isolated subgraph * with no further scope to extend it. */ for (y = 0; y < H; y++) for (x = 0; x < W; x++) { if (y == 0 || y == H-1 || x == 0 || x == W-1) sc->border[y*W+x] = TRUE; else sc->border[y*W+x] = FALSE; if (clues[y*W+x] < 0) sc->exits[y*W+x] = 4; else sc->exits[y*W+x] = clues[y*W+x]; } /* * Repeatedly try to deduce something until we can't. */ do { done_something = FALSE; /* * Any clue point with the number of remaining lines equal * to zero or to the number of remaining undecided * neighbouring squares can be filled in completely. */ for (y = 0; y < H; y++) for (x = 0; x < W; x++) { struct { int pos, slash; } neighbours[4]; int nneighbours; int nu, nl, c, s, eq, eq2, last, meq, mj1, mj2; if ((c = clues[y*W+x]) < 0) continue; /* * We have a clue point. Start by listing its * neighbouring squares, in order around the point, * together with the type of slash that would be * required in that square to connect to the point. */ nneighbours = 0; if (x > 0 && y > 0) { neighbours[nneighbours].pos = (y-1)*w+(x-1); neighbours[nneighbours].slash = -1; nneighbours++; } if (x > 0 && y < h) { neighbours[nneighbours].pos = y*w+(x-1); neighbours[nneighbours].slash = +1; nneighbours++; } if (x < w && y < h) { neighbours[nneighbours].pos = y*w+x; neighbours[nneighbours].slash = -1; nneighbours++; } if (x < w && y > 0) { neighbours[nneighbours].pos = (y-1)*w+x; neighbours[nneighbours].slash = +1; nneighbours++; } /* * Count up the number of undecided neighbours, and * also the number of lines already present. * * If we're not on DIFF_EASY, then in this loop we * also track whether we've seen two adjacent empty * squares belonging to the same equivalence class * (meaning they have the same type of slash). If * so, we count them jointly as one line. */ nu = 0; nl = c; last = neighbours[nneighbours-1].pos; if (soln[last] == 0) eq = dsf_canonify(sc->equiv, last); else eq = -1; meq = mj1 = mj2 = -1; for (i = 0; i < nneighbours; i++) { j = neighbours[i].pos; s = neighbours[i].slash; if (soln[j] == 0) { nu++; /* undecided */ if (meq < 0 && difficulty > DIFF_EASY) { eq2 = dsf_canonify(sc->equiv, j); if (eq == eq2 && last != j) { /* * We've found an equivalent pair. * Mark it. This also inhibits any * further equivalence tracking * around this square, since we can * only handle one pair (and in * particular we want to avoid * being misled by two overlapping * equivalence pairs). */ meq = eq; mj1 = last; mj2 = j; nl--; /* count one line */ nu -= 2; /* and lose two undecideds */ } else eq = eq2; } } else { eq = -1; if (soln[j] == s) nl--; /* here's a line */ } last = j; } /* * Check the counts. */ if (nl < 0 || nl > nu) { /* * No consistent value for this at all! */ #ifdef SOLVER_DIAGNOSTICS if (verbose) printf("need %d / %d lines around clue point at %d,%d!\n", nl, nu, x, y); #endif return 0; /* impossible */ } if (nu > 0 && (nl == 0 || nl == nu)) { #ifdef SOLVER_DIAGNOSTICS if (verbose) { if (meq >= 0) printf("partially (since %d,%d == %d,%d) ", mj1%w, mj1/w, mj2%w, mj2/w); printf("%s around clue point at %d,%d\n", nl ? "filling" : "emptying", x, y); } #endif for (i = 0; i < nneighbours; i++) { j = neighbours[i].pos; s = neighbours[i].slash; if (soln[j] == 0 && j != mj1 && j != mj2) fill_square(w, h, j%w, j/w, (nl ? s : -s), soln, sc->connected, sc); } done_something = TRUE; } else if (nu == 2 && nl == 1 && difficulty > DIFF_EASY) { /* * If we have precisely two undecided squares * and precisely one line to place between * them, _and_ those squares are adjacent, then * we can mark them as equivalent to one * another. * * This even applies if meq >= 0: if we have a * 2 clue point and two of its neighbours are * already marked equivalent, we can indeed * mark the other two as equivalent. * * We don't bother with this on DIFF_EASY, * since we wouldn't have used the results * anyway. */ last = -1; for (i = 0; i < nneighbours; i++) { j = neighbours[i].pos; if (soln[j] == 0 && j != mj1 && j != mj2) { if (last < 0) last = i; else if (last == i-1 || (last == 0 && i == 3)) break; /* found a pair */ } } if (i < nneighbours) { int sv1, sv2; assert(last >= 0); /* * neighbours[last] and neighbours[i] are * the pair. Mark them equivalent. */ #ifdef SOLVER_DIAGNOSTICS if (verbose) { if (meq >= 0) printf("since %d,%d == %d,%d, ", mj1%w, mj1/w, mj2%w, mj2/w); } #endif mj1 = neighbours[last].pos; mj2 = neighbours[i].pos; #ifdef SOLVER_DIAGNOSTICS if (verbose) printf("clue point at %d,%d implies %d,%d == %d," "%d\n", x, y, mj1%w, mj1/w, mj2%w, mj2/w); #endif mj1 = dsf_canonify(sc->equiv, mj1); sv1 = sc->slashval[mj1]; mj2 = dsf_canonify(sc->equiv, mj2); sv2 = sc->slashval[mj2]; if (sv1 != 0 && sv2 != 0 && sv1 != sv2) { #ifdef SOLVER_DIAGNOSTICS if (verbose) printf("merged two equivalence classes with" " different slash values!\n"); #endif return 0; } sv1 = sv1 ? sv1 : sv2; dsf_merge(sc->equiv, mj1, mj2); mj1 = dsf_canonify(sc->equiv, mj1); sc->slashval[mj1] = sv1; } } } if (done_something) continue; /* * Failing that, we now apply the second condition, which * is that no square may be filled in such a way as to form * a loop. Also in this loop (since it's over squares * rather than points), we check slashval to see if we've * already filled in another square in the same equivalence * class. * * The slashval check is disabled on DIFF_EASY, as is dead * end avoidance. Only _immediate_ loop avoidance remains. */ for (y = 0; y < h; y++) for (x = 0; x < w; x++) { int fs, bs, v; int c1, c2; #ifdef SOLVER_DIAGNOSTICS char *reason = ""; #endif if (soln[y*w+x]) continue; /* got this one already */ fs = FALSE; bs = FALSE; if (difficulty > DIFF_EASY) v = sc->slashval[dsf_canonify(sc->equiv, y*w+x)]; else v = 0; /* * Try to rule out connectivity between (x,y) and * (x+1,y+1); if successful, we will deduce that we * must have a forward slash. */ c1 = dsf_canonify(sc->connected, y*W+x); c2 = dsf_canonify(sc->connected, (y+1)*W+(x+1)); if (c1 == c2) { fs = TRUE; #ifdef SOLVER_DIAGNOSTICS reason = "simple loop avoidance"; #endif } if (difficulty > DIFF_EASY && !sc->border[c1] && !sc->border[c2] && sc->exits[c1] <= 1 && sc->exits[c2] <= 1) { fs = TRUE; #ifdef SOLVER_DIAGNOSTICS reason = "dead end avoidance"; #endif } if (v == +1) { fs = TRUE; #ifdef SOLVER_DIAGNOSTICS reason = "equivalence to an already filled square"; #endif } /* * Now do the same between (x+1,y) and (x,y+1), to * see if we are required to have a backslash. */ c1 = dsf_canonify(sc->connected, y*W+(x+1)); c2 = dsf_canonify(sc->connected, (y+1)*W+x); if (c1 == c2) { bs = TRUE; #ifdef SOLVER_DIAGNOSTICS reason = "simple loop avoidance"; #endif } if (difficulty > DIFF_EASY && !sc->border[c1] && !sc->border[c2] && sc->exits[c1] <= 1 && sc->exits[c2] <= 1) { bs = TRUE; #ifdef SOLVER_DIAGNOSTICS reason = "dead end avoidance"; #endif } if (v == -1) { bs = TRUE; #ifdef SOLVER_DIAGNOSTICS reason = "equivalence to an already filled square"; #endif } if (fs && bs) { /* * No consistent value for this at all! */ #ifdef SOLVER_DIAGNOSTICS if (verbose) printf("%d,%d has no consistent slash!\n", x, y); #endif return 0; /* impossible */ } if (fs) { #ifdef SOLVER_DIAGNOSTICS if (verbose) printf("employing %s\n", reason); #endif fill_square(w, h, x, y, +1, soln, sc->connected, sc); done_something = TRUE; } else if (bs) { #ifdef SOLVER_DIAGNOSTICS if (verbose) printf("employing %s\n", reason); #endif fill_square(w, h, x, y, -1, soln, sc->connected, sc); done_something = TRUE; } } if (done_something) continue; /* * Now see what we can do with the vbitmap array. All * vbitmap deductions are disabled at Easy level. */ if (difficulty <= DIFF_EASY) continue; for (y = 0; y < h; y++) for (x = 0; x < w; x++) { int s, c; /* * Any line already placed in a square must rule * out any type of v which contradicts it. */ if ((s = soln[y*w+x]) != 0) { if (x > 0) done_something |= vbitmap_clear(w, h, sc, x-1, y, (s < 0 ? 0x1 : 0x2), "contradicts known edge at (%d,%d)",x,y); if (x+1 < w) done_something |= vbitmap_clear(w, h, sc, x, y, (s < 0 ? 0x2 : 0x1), "contradicts known edge at (%d,%d)",x,y); if (y > 0) done_something |= vbitmap_clear(w, h, sc, x, y-1, (s < 0 ? 0x4 : 0x8), "contradicts known edge at (%d,%d)",x,y); if (y+1 < h) done_something |= vbitmap_clear(w, h, sc, x, y, (s < 0 ? 0x8 : 0x4), "contradicts known edge at (%d,%d)",x,y); } /* * If both types of v are ruled out for a pair of * adjacent squares, mark them as equivalent. */ if (x+1 < w && !(sc->vbitmap[y*w+x] & 0x3)) { int n1 = y*w+x, n2 = y*w+(x+1); if (dsf_canonify(sc->equiv, n1) != dsf_canonify(sc->equiv, n2)) { dsf_merge(sc->equiv, n1, n2); done_something = TRUE; #ifdef SOLVER_DIAGNOSTICS if (verbose) printf("(%d,%d) and (%d,%d) must be equivalent" " because both v-shapes are ruled out\n", x, y, x+1, y); #endif } } if (y+1 < h && !(sc->vbitmap[y*w+x] & 0xC)) { int n1 = y*w+x, n2 = (y+1)*w+x; if (dsf_canonify(sc->equiv, n1) != dsf_canonify(sc->equiv, n2)) { dsf_merge(sc->equiv, n1, n2); done_something = TRUE; #ifdef SOLVER_DIAGNOSTICS if (verbose) printf("(%d,%d) and (%d,%d) must be equivalent" " because both v-shapes are ruled out\n", x, y, x, y+1); #endif } } /* * The remaining work in this loop only works * around non-edge clue points. */ if (y == 0 || x == 0) continue; if ((c = clues[y*W+x]) < 0) continue; /* * x,y marks a clue point not on the grid edge. See * if this clue point allows us to rule out any v * shapes. */ if (c == 1) { /* * A 1 clue can never have any v shape pointing * at it. */ done_something |= vbitmap_clear(w, h, sc, x-1, y-1, 0x5, "points at 1 clue at (%d,%d)", x, y); done_something |= vbitmap_clear(w, h, sc, x-1, y, 0x2, "points at 1 clue at (%d,%d)", x, y); done_something |= vbitmap_clear(w, h, sc, x, y-1, 0x8, "points at 1 clue at (%d,%d)", x, y); } else if (c == 3) { /* * A 3 clue can never have any v shape pointing * away from it. */ done_something |= vbitmap_clear(w, h, sc, x-1, y-1, 0xA, "points away from 3 clue at (%d,%d)", x, y); done_something |= vbitmap_clear(w, h, sc, x-1, y, 0x1, "points away from 3 clue at (%d,%d)", x, y); done_something |= vbitmap_clear(w, h, sc, x, y-1, 0x4, "points away from 3 clue at (%d,%d)", x, y); } else if (c == 2) { /* * If a 2 clue has any kind of v ruled out on * one side of it, the same v is ruled out on * the other side. */ done_something |= vbitmap_clear(w, h, sc, x-1, y-1, (sc->vbitmap[(y )*w+(x-1)] & 0x3) ^ 0x3, "propagated by 2 clue at (%d,%d)", x, y); done_something |= vbitmap_clear(w, h, sc, x-1, y-1, (sc->vbitmap[(y-1)*w+(x )] & 0xC) ^ 0xC, "propagated by 2 clue at (%d,%d)", x, y); done_something |= vbitmap_clear(w, h, sc, x-1, y, (sc->vbitmap[(y-1)*w+(x-1)] & 0x3) ^ 0x3, "propagated by 2 clue at (%d,%d)", x, y); done_something |= vbitmap_clear(w, h, sc, x, y-1, (sc->vbitmap[(y-1)*w+(x-1)] & 0xC) ^ 0xC, "propagated by 2 clue at (%d,%d)", x, y); } #undef CLEARBITS } } while (done_something); /* * Solver can make no more progress. See if the grid is full. */ for (i = 0; i < w*h; i++) if (!soln[i]) return 2; /* failed to converge */ return 1; /* success */ } /* * Filled-grid generator. */ static void slant_generate(int w, int h, signed char *soln, random_state *rs) { int W = w+1, H = h+1; int x, y, i; int *connected, *indices; /* * Clear the output. */ memset(soln, 0, w*h); /* * Establish a disjoint set forest for tracking connectedness * between grid points. */ connected = snew_dsf(W*H); /* * Prepare a list of the squares in the grid, and fill them in * in a random order. */ indices = snewn(w*h, int); for (i = 0; i < w*h; i++) indices[i] = i; shuffle(indices, w*h, sizeof(*indices), rs); /* * Fill in each one in turn. */ for (i = 0; i < w*h; i++) { int fs, bs, v; y = indices[i] / w; x = indices[i] % w; fs = (dsf_canonify(connected, y*W+x) == dsf_canonify(connected, (y+1)*W+(x+1))); bs = (dsf_canonify(connected, (y+1)*W+x) == dsf_canonify(connected, y*W+(x+1))); /* * It isn't possible to get into a situation where we * aren't allowed to place _either_ type of slash in a * square. Thus, filled-grid generation never has to * backtrack. * * Proof (thanks to Gareth Taylor): * * If it were possible, it would have to be because there * was an existing path (not using this square) between the * top-left and bottom-right corners of this square, and * another between the other two. These two paths would * have to cross at some point. * * Obviously they can't cross in the middle of a square, so * they must cross by sharing a point in common. But this * isn't possible either: if you chessboard-colour all the * points on the grid, you find that any continuous * diagonal path is entirely composed of points of the same * colour. And one of our two hypothetical paths is between * two black points, and the other is between two white * points - therefore they can have no point in common. [] */ assert(!(fs && bs)); v = fs ? +1 : bs ? -1 : 2 * random_upto(rs, 2) - 1; fill_square(w, h, x, y, v, soln, connected, NULL); } sfree(indices); sfree(connected); } static char *new_game_desc(game_params *params, random_state *rs, char **aux, int interactive) { int w = params->w, h = params->h, W = w+1, H = h+1; signed char *soln, *tmpsoln, *clues; int *clueindices; struct solver_scratch *sc; int x, y, v, i, j; char *desc; soln = snewn(w*h, signed char); tmpsoln = snewn(w*h, signed char); clues = snewn(W*H, signed char); clueindices = snewn(W*H, int); sc = new_scratch(w, h); do { /* * Create the filled grid. */ slant_generate(w, h, soln, rs); /* * Fill in the complete set of clues. */ for (y = 0; y < H; y++) for (x = 0; x < W; x++) { v = 0; if (x > 0 && y > 0 && soln[(y-1)*w+(x-1)] == -1) v++; if (x > 0 && y < h && soln[y*w+(x-1)] == +1) v++; if (x < w && y > 0 && soln[(y-1)*w+x] == +1) v++; if (x < w && y < h && soln[y*w+x] == -1) v++; clues[y*W+x] = v; } /* * With all clue points filled in, all puzzles are easy: we can * simply process the clue points in lexicographic order, and * at each clue point we will always have at most one square * undecided, which we can then fill in uniquely. */ assert(slant_solve(w, h, clues, tmpsoln, sc, DIFF_EASY) == 1); /* * Remove as many clues as possible while retaining solubility. * * In DIFF_HARD mode, we prioritise the removal of obvious * starting points (4s, 0s, border 2s and corner 1s), on * the grounds that having as few of these as possible * seems like a good thing. In particular, we can often get * away without _any_ completely obvious starting points, * which is even better. */ for (i = 0; i < W*H; i++) clueindices[i] = i; shuffle(clueindices, W*H, sizeof(*clueindices), rs); for (j = 0; j < 2; j++) { for (i = 0; i < W*H; i++) { int pass, yb, xb; y = clueindices[i] / W; x = clueindices[i] % W; v = clues[y*W+x]; /* * Identify which pass we should process this point * in. If it's an obvious start point, _or_ we're * in DIFF_EASY, then it goes in pass 0; otherwise * pass 1. */ xb = (x == 0 || x == W-1); yb = (y == 0 || y == H-1); if (params->diff == DIFF_EASY || v == 4 || v == 0 || (v == 2 && (xb||yb)) || (v == 1 && xb && yb)) pass = 0; else pass = 1; if (pass == j) { clues[y*W+x] = -1; if (slant_solve(w, h, clues, tmpsoln, sc, params->diff) != 1) clues[y*W+x] = v; /* put it back */ } } } /* * And finally, verify that the grid is of _at least_ the * requested difficulty, by running the solver one level * down and verifying that it can't manage it. */ } while (params->diff > 0 && slant_solve(w, h, clues, tmpsoln, sc, params->diff - 1) <= 1); /* * Now we have the clue set as it will be presented to the * user. Encode it in a game desc. */ { char *p; int run, i; desc = snewn(W*H+1, char); p = desc; run = 0; for (i = 0; i <= W*H; i++) { int n = (i < W*H ? clues[i] : -2); if (n == -1) run++; else { if (run) { while (run > 0) { int c = 'a' - 1 + run; if (run > 26) c = 'z'; *p++ = c; run -= c - ('a' - 1); } } if (n >= 0) *p++ = '0' + n; run = 0; } } assert(p - desc <= W*H); *p++ = '\0'; desc = sresize(desc, p - desc, char); } /* * Encode the solution as an aux_info. */ { char *auxbuf; *aux = auxbuf = snewn(w*h+1, char); for (i = 0; i < w*h; i++) auxbuf[i] = soln[i] < 0 ? '\\' : '/'; auxbuf[w*h] = '\0'; } free_scratch(sc); sfree(clueindices); sfree(clues); sfree(tmpsoln); sfree(soln); return desc; } static char *validate_desc(game_params *params, char *desc) { int w = params->w, h = params->h, W = w+1, H = h+1; int area = W*H; int squares = 0; while (*desc) { int n = *desc++; if (n >= 'a' && n <= 'z') { squares += n - 'a' + 1; } else if (n >= '0' && n <= '4') { squares++; } else return "Invalid character in game description"; } if (squares < area) return "Not enough data to fill grid"; if (squares > area) return "Too much data to fit in grid"; return NULL; } static game_state *new_game(midend *me, game_params *params, char *desc) { int w = params->w, h = params->h, W = w+1, H = h+1; game_state *state = snew(game_state); int area = W*H; int squares = 0; state->p = *params; state->soln = snewn(w*h, signed char); memset(state->soln, 0, w*h); state->completed = state->used_solve = FALSE; state->errors = snewn(W*H, unsigned char); memset(state->errors, 0, W*H); state->clues = snew(game_clues); state->clues->w = w; state->clues->h = h; state->clues->clues = snewn(W*H, signed char); state->clues->refcount = 1; state->clues->tmpdsf = snewn(W*H, int); memset(state->clues->clues, -1, W*H); while (*desc) { int n = *desc++; if (n >= 'a' && n <= 'z') { squares += n - 'a' + 1; } else if (n >= '0' && n <= '4') { state->clues->clues[squares++] = n - '0'; } else assert(!"can't get here"); } assert(squares == area); return state; } static game_state *dup_game(game_state *state) { int w = state->p.w, h = state->p.h, W = w+1, H = h+1; game_state *ret = snew(game_state); ret->p = state->p; ret->clues = state->clues; ret->clues->refcount++; ret->completed = state->completed; ret->used_solve = state->used_solve; ret->soln = snewn(w*h, signed char); memcpy(ret->soln, state->soln, w*h); ret->errors = snewn(W*H, unsigned char); memcpy(ret->errors, state->errors, W*H); return ret; } static void free_game(game_state *state) { sfree(state->errors); sfree(state->soln); assert(state->clues); if (--state->clues->refcount <= 0) { sfree(state->clues->clues); sfree(state->clues->tmpdsf); sfree(state->clues); } sfree(state); } /* * Utility function to return the current degree of a vertex. If * `anti' is set, it returns the number of filled-in edges * surrounding the point which _don't_ connect to it; thus 4 minus * its anti-degree is the maximum degree it could have if all the * empty spaces around it were filled in. * * (Yes, _4_ minus its anti-degree even if it's a border vertex.) * * If ret > 0, *sx and *sy are set to the coordinates of one of the * squares that contributed to it. */ static int vertex_degree(int w, int h, signed char *soln, int x, int y, int anti, int *sx, int *sy) { int ret = 0; assert(x >= 0 && x <= w && y >= 0 && y <= h); if (x > 0 && y > 0 && soln[(y-1)*w+(x-1)] - anti < 0) { if (sx) *sx = x-1; if (sy) *sy = y-1; ret++; } if (x > 0 && y < h && soln[y*w+(x-1)] + anti > 0) { if (sx) *sx = x-1; if (sy) *sy = y; ret++; } if (x < w && y > 0 && soln[(y-1)*w+x] + anti > 0) { if (sx) *sx = x; if (sy) *sy = y-1; ret++; } if (x < w && y < h && soln[y*w+x] - anti < 0) { if (sx) *sx = x; if (sy) *sy = y; ret++; } return anti ? 4 - ret : ret; } static int check_completion(game_state *state) { int w = state->p.w, h = state->p.h, W = w+1, H = h+1; int i, x, y, err = FALSE; int *dsf; memset(state->errors, 0, W*H); /* * To detect loops in the grid, we iterate through each edge * building up a dsf of connected components, and raise the * alarm whenever we find an edge that connects two * already-connected vertices. * * We use the `tmpdsf' scratch space in the shared clues * structure, to avoid mallocing too often. * * When we find such an edge, we then search around the grid to * find the loop it is a part of, so that we can highlight it * as an error for the user. We do this by the hand-on-one-wall * technique: the search will follow branches off the inside of * the loop, discover they're dead ends, and unhighlight them * again when returning to the actual loop. * * This technique guarantees that every loop it tracks will * surround a disjoint area of the grid (since if an existing * loop appears on the boundary of a new one, so that there are * multiple possible paths that would come back to the starting * point, it will pick the one that allows it to turn right * most sharply and hence the one that does not re-surround the * area of the previous one). Thus, the total time taken in * searching round loops is linear in the grid area since every * edge is visited at most twice. */ dsf = state->clues->tmpdsf; dsf_init(dsf, W*H); for (y = 0; y < h; y++) for (x = 0; x < w; x++) { int i1, i2; if (state->soln[y*w+x] == 0) continue; if (state->soln[y*w+x] < 0) { i1 = y*W+x; i2 = (y+1)*W+(x+1); } else { i1 = y*W+(x+1); i2 = (y+1)*W+x; } /* * Our edge connects i1 with i2. If they're already * connected, flag an error. Otherwise, link them. */ if (dsf_canonify(dsf, i1) == dsf_canonify(dsf, i2)) { int x1, y1, x2, y2, dx, dy, dt, pass; err = TRUE; /* * Now search around the boundary of the loop to * highlight it. * * We have to do this in two passes. The first * time, we toggle ERR_SQUARE_TMP on each edge; * this pass terminates with ERR_SQUARE_TMP set on * exactly the loop edges. In the second pass, we * trace round that loop again and turn * ERR_SQUARE_TMP into ERR_SQUARE. We have to do * this because otherwise we might cancel part of a * loop highlighted in a previous iteration of the * outer loop. */ for (pass = 0; pass < 2; pass++) { x1 = i1 % W; y1 = i1 / W; x2 = i2 % W; y2 = i2 / W; do { /* Mark this edge. */ if (pass == 0) { state->errors[min(y1,y2)*W+min(x1,x2)] ^= ERR_SQUARE_TMP; } else { state->errors[min(y1,y2)*W+min(x1,x2)] |= ERR_SQUARE; state->errors[min(y1,y2)*W+min(x1,x2)] &= ~ERR_SQUARE_TMP; } /* * Progress to the next edge by turning as * sharply right as possible. In fact we do * this by facing back along the edge and * turning _left_ until we see an edge we * can follow. */ dx = x1 - x2; dy = y1 - y2; for (i = 0; i < 4; i++) { /* * Rotate (dx,dy) to the left. */ dt = dx; dx = dy; dy = -dt; /* * See if (x2,y2) has an edge in direction * (dx,dy). */ if (x2+dx < 0 || x2+dx >= W || y2+dy < 0 || y2+dy >= H) continue; /* off the side of the grid */ /* In the second pass, ignore unmarked edges. */ if (pass == 1 && !(state->errors[(y2-(dy<0))*W+x2-(dx<0)] & ERR_SQUARE_TMP)) continue; if (state->soln[(y2-(dy<0))*w+x2-(dx<0)] == (dx==dy ? -1 : +1)) break; } /* * In pass 0, we expect to have found * _some_ edge we can follow, even if it * was found by rotating all the way round * and going back the way we came. * * In pass 1, because we're removing the * mark on each edge that allows us to * follow it, we expect to find _no_ edge * we can follow when we've come all the * way round the loop. */ if (pass == 1 && i == 4) break; assert(i < 4); /* * Set x1,y1 to x2,y2, and x2,y2 to be the * other end of the new edge. */ x1 = x2; y1 = y2; x2 += dx; y2 += dy; } while (y2*W+x2 != i2); } } else dsf_merge(dsf, i1, i2); } /* * Now go through and check the degree of each clue vertex, and * mark it with ERR_VERTEX if it cannot be fulfilled. */ for (y = 0; y < H; y++) for (x = 0; x < W; x++) { int c; if ((c = state->clues->clues[y*W+x]) < 0) continue; /* * Check to see if there are too many connections to * this vertex _or_ too many non-connections. Either is * grounds for marking the vertex as erroneous. */ if (vertex_degree(w, h, state->soln, x, y, FALSE, NULL, NULL) > c || vertex_degree(w, h, state->soln, x, y, TRUE, NULL, NULL) > 4-c) { state->errors[y*W+x] |= ERR_VERTEX; err = TRUE; } } /* * Now our actual victory condition is that (a) none of the * above code marked anything as erroneous, and (b) every * square has an edge in it. */ if (err) return FALSE; for (y = 0; y < h; y++) for (x = 0; x < w; x++) if (state->soln[y*w+x] == 0) return FALSE; return TRUE; } static char *solve_game(game_state *state, game_state *currstate, char *aux, char **error) { int w = state->p.w, h = state->p.h; signed char *soln; int bs, ret; int free_soln = FALSE; char *move, buf[80]; int movelen, movesize; int x, y; if (aux) { /* * If we already have the solution, save ourselves some * time. */ soln = (signed char *)aux; bs = (signed char)'\\'; free_soln = FALSE; } else { struct solver_scratch *sc = new_scratch(w, h); soln = snewn(w*h, signed char); bs = -1; ret = slant_solve(w, h, state->clues->clues, soln, sc, DIFF_HARD); free_scratch(sc); if (ret != 1) { sfree(soln); if (ret == 0) *error = "This puzzle is not self-consistent"; else *error = "Unable to find a unique solution for this puzzle"; return NULL; } free_soln = TRUE; } /* * Construct a move string which turns the current state into * the solved state. */ movesize = 256; move = snewn(movesize, char); movelen = 0; move[movelen++] = 'S'; move[movelen] = '\0'; for (y = 0; y < h; y++) for (x = 0; x < w; x++) { int v = (soln[y*w+x] == bs ? -1 : +1); if (state->soln[y*w+x] != v) { int len = sprintf(buf, ";%c%d,%d", (int)(v < 0 ? '\\' : '/'), x, y); if (movelen + len >= movesize) { movesize = movelen + len + 256; move = sresize(move, movesize, char); } strcpy(move + movelen, buf); movelen += len; } } if (free_soln) sfree(soln); return move; } static char *game_text_format(game_state *state) { int w = state->p.w, h = state->p.h, W = w+1, H = h+1; int x, y, len; char *ret, *p; /* * There are h+H rows of w+W columns. */ len = (h+H) * (w+W+1) + 1; ret = snewn(len, char); p = ret; for (y = 0; y < H; y++) { for (x = 0; x < W; x++) { if (state->clues->clues[y*W+x] >= 0) *p++ = state->clues->clues[y*W+x] + '0'; else *p++ = '+'; if (x < w) *p++ = '-'; } *p++ = '\n'; if (y < h) { for (x = 0; x < W; x++) { *p++ = '|'; if (x < w) { if (state->soln[y*w+x] != 0) *p++ = (state->soln[y*w+x] < 0 ? '\\' : '/'); else *p++ = ' '; } } *p++ = '\n'; } } *p++ = '\0'; assert(p - ret == len); return ret; } static game_ui *new_ui(game_state *state) { return NULL; } static void free_ui(game_ui *ui) { } static char *encode_ui(game_ui *ui) { return NULL; } static void decode_ui(game_ui *ui, char *encoding) { } static void game_changed_state(game_ui *ui, game_state *oldstate, game_state *newstate) { } #define PREFERRED_TILESIZE 32 #define TILESIZE (ds->tilesize) #define BORDER TILESIZE #define CLUE_RADIUS (TILESIZE / 3) #define CLUE_TEXTSIZE (TILESIZE / 2) #define COORD(x) ( (x) * TILESIZE + BORDER ) #define FROMCOORD(x) ( ((x) - BORDER + TILESIZE) / TILESIZE - 1 ) #define FLASH_TIME 0.30F /* * Bit fields in the `grid' and `todraw' elements of the drawstate. */ #define BACKSLASH 0x00000001L #define FORWSLASH 0x00000002L #define L_T 0x00000004L #define ERR_L_T 0x00000008L #define L_B 0x00000010L #define ERR_L_B 0x00000020L #define T_L 0x00000040L #define ERR_T_L 0x00000080L #define T_R 0x00000100L #define ERR_T_R 0x00000200L #define C_TL 0x00000400L #define ERR_C_TL 0x00000800L #define FLASH 0x00001000L #define ERRSLASH 0x00002000L #define ERR_TL 0x00004000L #define ERR_TR 0x00008000L #define ERR_BL 0x00010000L #define ERR_BR 0x00020000L struct game_drawstate { int tilesize; int started; long *grid; long *todraw; }; static char *interpret_move(game_state *state, game_ui *ui, game_drawstate *ds, int x, int y, int button) { int w = state->p.w, h = state->p.h; if (button == LEFT_BUTTON || button == RIGHT_BUTTON) { int v; char buf[80]; /* * This is an utterly awful hack which I should really sort out * by means of a proper configuration mechanism. One Slant * player has observed that they prefer the mouse buttons to * function exactly the opposite way round, so here's a * mechanism for environment-based configuration. I cache the * result in a global variable - yuck! - to avoid repeated * lookups. */ { static int swap_buttons = -1; if (swap_buttons < 0) { char *env = getenv("SLANT_SWAP_BUTTONS"); swap_buttons = (env && (env[0] == 'y' || env[0] == 'Y')); } if (swap_buttons) { if (button == LEFT_BUTTON) button = RIGHT_BUTTON; else button = LEFT_BUTTON; } } x = FROMCOORD(x); y = FROMCOORD(y); if (x < 0 || y < 0 || x >= w || y >= h) return NULL; if (button == LEFT_BUTTON) { /* * Left-clicking cycles blank -> \ -> / -> blank. */ v = state->soln[y*w+x] - 1; if (v == -2) v = +1; } else { /* * Right-clicking cycles blank -> / -> \ -> blank. */ v = state->soln[y*w+x] + 1; if (v == +2) v = -1; } sprintf(buf, "%c%d,%d", (int)(v==-1 ? '\\' : v==+1 ? '/' : 'C'), x, y); return dupstr(buf); } return NULL; } static game_state *execute_move(game_state *state, char *move) { int w = state->p.w, h = state->p.h; char c; int x, y, n; game_state *ret = dup_game(state); while (*move) { c = *move; if (c == 'S') { ret->used_solve = TRUE; move++; } else if (c == '\\' || c == '/' || c == 'C') { move++; if (sscanf(move, "%d,%d%n", &x, &y, &n) != 2 || x < 0 || y < 0 || x >= w || y >= h) { free_game(ret); return NULL; } ret->soln[y*w+x] = (c == '\\' ? -1 : c == '/' ? +1 : 0); move += n; } else { free_game(ret); return NULL; } if (*move == ';') move++; else if (*move) { free_game(ret); return NULL; } } /* * We never clear the `completed' flag, but we must always * re-run the completion check because it also highlights * errors in the grid. */ ret->completed = check_completion(ret) || ret->completed; return ret; } /* ---------------------------------------------------------------------- * Drawing routines. */ static void game_compute_size(game_params *params, int tilesize, int *x, int *y) { /* fool the macros */ struct dummy { int tilesize; } dummy = { tilesize }, *ds = &dummy; *x = 2 * BORDER + params->w * TILESIZE + 1; *y = 2 * BORDER + params->h * TILESIZE + 1; } static void game_set_size(drawing *dr, game_drawstate *ds, game_params *params, int tilesize) { ds->tilesize = tilesize; } static float *game_colours(frontend *fe, int *ncolours) { float *ret = snewn(3 * NCOLOURS, float); frontend_default_colour(fe, &ret[COL_BACKGROUND * 3]); ret[COL_GRID * 3 + 0] = ret[COL_BACKGROUND * 3 + 0] * 0.7F; ret[COL_GRID * 3 + 1] = ret[COL_BACKGROUND * 3 + 1] * 0.7F; ret[COL_GRID * 3 + 2] = ret[COL_BACKGROUND * 3 + 2] * 0.7F; ret[COL_INK * 3 + 0] = 0.0F; ret[COL_INK * 3 + 1] = 0.0F; ret[COL_INK * 3 + 2] = 0.0F; ret[COL_SLANT1 * 3 + 0] = 0.0F; ret[COL_SLANT1 * 3 + 1] = 0.0F; ret[COL_SLANT1 * 3 + 2] = 0.0F; ret[COL_SLANT2 * 3 + 0] = 0.0F; ret[COL_SLANT2 * 3 + 1] = 0.0F; ret[COL_SLANT2 * 3 + 2] = 0.0F; ret[COL_ERROR * 3 + 0] = 1.0F; ret[COL_ERROR * 3 + 1] = 0.0F; ret[COL_ERROR * 3 + 2] = 0.0F; *ncolours = NCOLOURS; return ret; } static game_drawstate *game_new_drawstate(drawing *dr, game_state *state) { int w = state->p.w, h = state->p.h; int i; struct game_drawstate *ds = snew(struct game_drawstate); ds->tilesize = 0; ds->started = FALSE; ds->grid = snewn((w+2)*(h+2), long); ds->todraw = snewn((w+2)*(h+2), long); for (i = 0; i < (w+2)*(h+2); i++) ds->grid[i] = ds->todraw[i] = -1; return ds; } static void game_free_drawstate(drawing *dr, game_drawstate *ds) { sfree(ds->todraw); sfree(ds->grid); sfree(ds); } static void draw_clue(drawing *dr, game_drawstate *ds, int x, int y, long v, long err, int bg, int colour) { char p[2]; int ccol = colour >= 0 ? colour : ((x ^ y) & 1) ? COL_SLANT1 : COL_SLANT2; int tcol = colour >= 0 ? colour : err ? COL_ERROR : COL_INK; if (v < 0) return; p[0] = v + '0'; p[1] = '\0'; draw_circle(dr, COORD(x), COORD(y), CLUE_RADIUS, bg >= 0 ? bg : COL_BACKGROUND, ccol); draw_text(dr, COORD(x), COORD(y), FONT_VARIABLE, CLUE_TEXTSIZE, ALIGN_VCENTRE|ALIGN_HCENTRE, tcol, p); } static void draw_tile(drawing *dr, game_drawstate *ds, game_clues *clues, int x, int y, long v) { int w = clues->w, h = clues->h, W = w+1 /*, H = h+1 */; int chesscolour = (x ^ y) & 1; int fscol = chesscolour ? COL_SLANT2 : COL_SLANT1; int bscol = chesscolour ? COL_SLANT1 : COL_SLANT2; clip(dr, COORD(x), COORD(y), TILESIZE, TILESIZE); draw_rect(dr, COORD(x), COORD(y), TILESIZE, TILESIZE, (v & FLASH) ? COL_GRID : COL_BACKGROUND); /* * Draw the grid lines. */ if (x >= 0 && x < w && y >= 0) draw_rect(dr, COORD(x), COORD(y), TILESIZE+1, 1, COL_GRID); if (x >= 0 && x < w && y < h) draw_rect(dr, COORD(x), COORD(y+1), TILESIZE+1, 1, COL_GRID); if (y >= 0 && y < h && x >= 0) draw_rect(dr, COORD(x), COORD(y), 1, TILESIZE+1, COL_GRID); if (y >= 0 && y < h && x < w) draw_rect(dr, COORD(x+1), COORD(y), 1, TILESIZE+1, COL_GRID); if (x == -1 && y == -1) draw_rect(dr, COORD(x+1), COORD(y+1), 1, 1, COL_GRID); if (x == -1 && y == h) draw_rect(dr, COORD(x+1), COORD(y), 1, 1, COL_GRID); if (x == w && y == -1) draw_rect(dr, COORD(x), COORD(y+1), 1, 1, COL_GRID); if (x == w && y == h) draw_rect(dr, COORD(x), COORD(y), 1, 1, COL_GRID); /* * Draw the slash. */ if (v & BACKSLASH) { int scol = (v & ERRSLASH) ? COL_ERROR : bscol; draw_line(dr, COORD(x), COORD(y), COORD(x+1), COORD(y+1), scol); draw_line(dr, COORD(x)+1, COORD(y), COORD(x+1), COORD(y+1)-1, scol); draw_line(dr, COORD(x), COORD(y)+1, COORD(x+1)-1, COORD(y+1), scol); } else if (v & FORWSLASH) { int scol = (v & ERRSLASH) ? COL_ERROR : fscol; draw_line(dr, COORD(x+1), COORD(y), COORD(x), COORD(y+1), scol); draw_line(dr, COORD(x+1)-1, COORD(y), COORD(x), COORD(y+1)-1, scol); draw_line(dr, COORD(x+1), COORD(y)+1, COORD(x)+1, COORD(y+1), scol); } /* * Draw dots on the grid corners that appear if a slash is in a * neighbouring cell. */ if (v & (L_T | BACKSLASH)) draw_rect(dr, COORD(x), COORD(y)+1, 1, 1, (v & ERR_L_T ? COL_ERROR : bscol)); if (v & (L_B | FORWSLASH)) draw_rect(dr, COORD(x), COORD(y+1)-1, 1, 1, (v & ERR_L_B ? COL_ERROR : fscol)); if (v & (T_L | BACKSLASH)) draw_rect(dr, COORD(x)+1, COORD(y), 1, 1, (v & ERR_T_L ? COL_ERROR : bscol)); if (v & (T_R | FORWSLASH)) draw_rect(dr, COORD(x+1)-1, COORD(y), 1, 1, (v & ERR_T_R ? COL_ERROR : fscol)); if (v & (C_TL | BACKSLASH)) draw_rect(dr, COORD(x), COORD(y), 1, 1, (v & ERR_C_TL ? COL_ERROR : bscol)); /* * And finally the clues at the corners. */ if (x >= 0 && y >= 0) draw_clue(dr, ds, x, y, clues->clues[y*W+x], v & ERR_TL, -1, -1); if (x < w && y >= 0) draw_clue(dr, ds, x+1, y, clues->clues[y*W+(x+1)], v & ERR_TR, -1, -1); if (x >= 0 && y < h) draw_clue(dr, ds, x, y+1, clues->clues[(y+1)*W+x], v & ERR_BL, -1, -1); if (x < w && y < h) draw_clue(dr, ds, x+1, y+1, clues->clues[(y+1)*W+(x+1)], v & ERR_BR, -1, -1); unclip(dr); draw_update(dr, COORD(x), COORD(y), TILESIZE, TILESIZE); } static void game_redraw(drawing *dr, game_drawstate *ds, game_state *oldstate, game_state *state, int dir, game_ui *ui, float animtime, float flashtime) { int w = state->p.w, h = state->p.h, W = w+1, H = h+1; int x, y; int flashing; if (flashtime > 0) flashing = (int)(flashtime * 3 / FLASH_TIME) != 1; else flashing = FALSE; if (!ds->started) { int ww, wh; game_compute_size(&state->p, TILESIZE, &ww, &wh); draw_rect(dr, 0, 0, ww, wh, COL_BACKGROUND); draw_update(dr, 0, 0, ww, wh); ds->started = TRUE; } /* * Loop over the grid and work out where all the slashes are. * We need to do this because a slash in one square affects the * drawing of the next one along. */ for (y = -1; y <= h; y++) for (x = -1; x <= w; x++) { if (x >= 0 && x < w && y >= 0 && y < h) ds->todraw[(y+1)*(w+2)+(x+1)] = flashing ? FLASH : 0; else ds->todraw[(y+1)*(w+2)+(x+1)] = 0; } for (y = 0; y < h; y++) { for (x = 0; x < w; x++) { int err = state->errors[y*W+x] & ERR_SQUARE; if (state->soln[y*w+x] < 0) { ds->todraw[(y+1)*(w+2)+(x+1)] |= BACKSLASH; ds->todraw[(y+2)*(w+2)+(x+1)] |= T_R; ds->todraw[(y+1)*(w+2)+(x+2)] |= L_B; ds->todraw[(y+2)*(w+2)+(x+2)] |= C_TL; if (err) { ds->todraw[(y+1)*(w+2)+(x+1)] |= ERRSLASH | ERR_T_L | ERR_L_T | ERR_C_TL; ds->todraw[(y+2)*(w+2)+(x+1)] |= ERR_T_R; ds->todraw[(y+1)*(w+2)+(x+2)] |= ERR_L_B; ds->todraw[(y+2)*(w+2)+(x+2)] |= ERR_C_TL; } } else if (state->soln[y*w+x] > 0) { ds->todraw[(y+1)*(w+2)+(x+1)] |= FORWSLASH; ds->todraw[(y+1)*(w+2)+(x+2)] |= L_T | C_TL; ds->todraw[(y+2)*(w+2)+(x+1)] |= T_L | C_TL; if (err) { ds->todraw[(y+1)*(w+2)+(x+1)] |= ERRSLASH | ERR_L_B | ERR_T_R; ds->todraw[(y+1)*(w+2)+(x+2)] |= ERR_L_T | ERR_C_TL; ds->todraw[(y+2)*(w+2)+(x+1)] |= ERR_T_L | ERR_C_TL; } } } } for (y = 0; y < H; y++) for (x = 0; x < W; x++) if (state->errors[y*W+x] & ERR_VERTEX) { ds->todraw[y*(w+2)+x] |= ERR_BR; ds->todraw[y*(w+2)+(x+1)] |= ERR_BL; ds->todraw[(y+1)*(w+2)+x] |= ERR_TR; ds->todraw[(y+1)*(w+2)+(x+1)] |= ERR_TL; } /* * Now go through and draw the grid squares. */ for (y = -1; y <= h; y++) { for (x = -1; x <= w; x++) { if (ds->todraw[(y+1)*(w+2)+(x+1)] != ds->grid[(y+1)*(w+2)+(x+1)]) { draw_tile(dr, ds, state->clues, x, y, ds->todraw[(y+1)*(w+2)+(x+1)]); ds->grid[(y+1)*(w+2)+(x+1)] = ds->todraw[(y+1)*(w+2)+(x+1)]; } } } } static float game_anim_length(game_state *oldstate, game_state *newstate, int dir, game_ui *ui) { return 0.0F; } static float game_flash_length(game_state *oldstate, game_state *newstate, int dir, game_ui *ui) { if (!oldstate->completed && newstate->completed && !oldstate->used_solve && !newstate->used_solve) return FLASH_TIME; return 0.0F; } static int game_timing_state(game_state *state, game_ui *ui) { return TRUE; } static void game_print_size(game_params *params, float *x, float *y) { int pw, ph; /* * I'll use 6mm squares by default. */ game_compute_size(params, 600, &pw, &ph); *x = pw / 100.0; *y = ph / 100.0; } static void game_print(drawing *dr, game_state *state, int tilesize) { int w = state->p.w, h = state->p.h, W = w+1; int ink = print_mono_colour(dr, 0); int paper = print_mono_colour(dr, 1); int x, y; /* Ick: fake up `ds->tilesize' for macro expansion purposes */ game_drawstate ads, *ds = &ads; game_set_size(dr, ds, NULL, tilesize); /* * Border. */ print_line_width(dr, TILESIZE / 16); draw_rect_outline(dr, COORD(0), COORD(0), w*TILESIZE, h*TILESIZE, ink); /* * Grid. */ print_line_width(dr, TILESIZE / 24); for (x = 1; x < w; x++) draw_line(dr, COORD(x), COORD(0), COORD(x), COORD(h), ink); for (y = 1; y < h; y++) draw_line(dr, COORD(0), COORD(y), COORD(w), COORD(y), ink); /* * Solution. */ print_line_width(dr, TILESIZE / 12); for (y = 0; y < h; y++) for (x = 0; x < w; x++) if (state->soln[y*w+x]) { int ly, ry; /* * To prevent nasty line-ending artefacts at * corners, I'll do something slightly cunning * here. */ clip(dr, COORD(x), COORD(y), TILESIZE, TILESIZE); if (state->soln[y*w+x] < 0) ly = y-1, ry = y+2; else ry = y-1, ly = y+2; draw_line(dr, COORD(x-1), COORD(ly), COORD(x+2), COORD(ry), ink); unclip(dr); } /* * Clues. */ print_line_width(dr, TILESIZE / 24); for (y = 0; y <= h; y++) for (x = 0; x <= w; x++) draw_clue(dr, ds, x, y, state->clues->clues[y*W+x], FALSE, paper, ink); } #ifdef COMBINED #define thegame slant #endif const struct game thegame = { "Slant", default_params, game_fetch_preset, decode_params, encode_params, free_params, dup_params, TRUE, game_configure, custom_params, validate_params, new_game_desc, validate_desc, new_game, dup_game, free_game, TRUE, solve_game, TRUE, game_text_format, new_ui, free_ui, encode_ui, decode_ui, game_changed_state, interpret_move, execute_move, PREFERRED_TILESIZE, game_compute_size, game_set_size, game_colours, game_new_drawstate, game_free_drawstate, game_redraw, game_anim_length, game_flash_length, TRUE, FALSE, game_print_size, game_print, FALSE, /* wants_statusbar */ FALSE, game_timing_state, 0, /* flags */ }; #ifdef STANDALONE_SOLVER #include int main(int argc, char **argv) { game_params *p; game_state *s; char *id = NULL, *desc, *err; int grade = FALSE; int ret, diff, really_verbose = FALSE; struct solver_scratch *sc; while (--argc > 0) { char *p = *++argv; if (!strcmp(p, "-v")) { really_verbose = TRUE; } else if (!strcmp(p, "-g")) { grade = TRUE; } else if (*p == '-') { fprintf(stderr, "%s: unrecognised option `%s'\n", argv[0], p); return 1; } else { id = p; } } if (!id) { fprintf(stderr, "usage: %s [-g | -v] \n", argv[0]); return 1; } desc = strchr(id, ':'); if (!desc) { fprintf(stderr, "%s: game id expects a colon in it\n", argv[0]); return 1; } *desc++ = '\0'; p = default_params(); decode_params(p, id); err = validate_desc(p, desc); if (err) { fprintf(stderr, "%s: %s\n", argv[0], err); return 1; } s = new_game(NULL, p, desc); sc = new_scratch(p->w, p->h); /* * When solving an Easy puzzle, we don't want to bother the * user with Hard-level deductions. For this reason, we grade * the puzzle internally before doing anything else. */ ret = -1; /* placate optimiser */ for (diff = 0; diff < DIFFCOUNT; diff++) { ret = slant_solve(p->w, p->h, s->clues->clues, s->soln, sc, diff); if (ret < 2) break; } if (diff == DIFFCOUNT) { if (grade) printf("Difficulty rating: harder than Hard, or ambiguous\n"); else printf("Unable to find a unique solution\n"); } else { if (grade) { if (ret == 0) printf("Difficulty rating: impossible (no solution exists)\n"); else if (ret == 1) printf("Difficulty rating: %s\n", slant_diffnames[diff]); } else { verbose = really_verbose; ret = slant_solve(p->w, p->h, s->clues->clues, s->soln, sc, diff); if (ret == 0) printf("Puzzle is inconsistent\n"); else fputs(game_text_format(s), stdout); } } return 0; } #endif