mdw@git.distorted.org.uk Git - sgt/puzzles/blob - fifteen.c

   1 /*
   2  * fifteen.c: standard 15-puzzle.
   3  */
   4
   5 #include <stdio.h>
   6 #include <stdlib.h>
   7 #include <string.h>
   8 #include <assert.h>
   9 #include <ctype.h>
  10 #include <math.h>
  11
  12 #include "puzzles.h"
  13
  14 #define TILE_SIZE 48
  15 #define BORDER    (TILE_SIZE / 2)
  16 #define HIGHLIGHT_WIDTH (TILE_SIZE / 20)
  17 #define COORD(x)  ( (x) * TILE_SIZE + BORDER )
  18 #define FROMCOORD(x)  ( ((x) - BORDER + TILE_SIZE) / TILE_SIZE - 1 )
  19
  20 #define ANIM_TIME 0.13F
  21 #define FLASH_FRAME 0.13F
  22
  23 #define X(state, i) ( (i) % (state)->w )
  24 #define Y(state, i) ( (i) / (state)->w )
  25 #define C(state, x, y) ( (y) * (state)->w + (x) )
  26
  27 enum {
  28     COL_BACKGROUND,
  29     COL_TEXT,
  30     COL_HIGHLIGHT,
  31     COL_LOWLIGHT,
  32     NCOLOURS
  33 };
  34
  35 struct game_params {
  36     int w, h;
  37 };
  38
  39 struct game_state {
  40     int w, h, n;
  41     int *tiles;
  42     int gap_pos;
  43     int completed;
  44     int movecount;
  45 };
  46
  47 static game_params *default_params(void)
  48 {
  49     game_params *ret = snew(game_params);
  50
  51     ret->w = ret->h = 4;
  52
  53     return ret;
  54 }
  55
  56 static int game_fetch_preset(int i, char **name, game_params **params)
  57 {
  58     return FALSE;
  59 }
  60
  61 static void free_params(game_params *params)
  62 {
  63     sfree(params);
  64 }
  65
  66 static game_params *dup_params(game_params *params)
  67 {
  68     game_params *ret = snew(game_params);
  69     *ret = *params;                    /* structure copy */
  70     return ret;
  71 }
  72
  73 static game_params *decode_params(char const *string)
  74 {
  75     game_params *ret = default_params();
  76
  77     ret->w = ret->h = atoi(string);
  78     while (*string && isdigit(*string)) string++;
  79     if (*string == 'x') {
  80         string++;
  81         ret->h = atoi(string);
  82     }
  83
  84     return ret;
  85 }
  86
  87 static char *encode_params(game_params *params)
  88 {
  89     char data[256];
  90
  91     sprintf(data, "%dx%d", params->w, params->h);
  92
  93     return dupstr(data);
  94 }
  95
  96 static config_item *game_configure(game_params *params)
  97 {
  98     config_item *ret;
  99     char buf[80];
 100
 101     ret = snewn(3, config_item);
 102
 103     ret[0].name = "Width";
 104     ret[0].type = C_STRING;
 105     sprintf(buf, "%d", params->w);
 106     ret[0].sval = dupstr(buf);
 107     ret[0].ival = 0;
 108
 109     ret[1].name = "Height";
 110     ret[1].type = C_STRING;
 111     sprintf(buf, "%d", params->h);
 112     ret[1].sval = dupstr(buf);
 113     ret[1].ival = 0;
 114
 115     ret[2].name = NULL;
 116     ret[2].type = C_END;
 117     ret[2].sval = NULL;
 118     ret[2].ival = 0;
 119
 120     return ret;
 121 }
 122
 123 static game_params *custom_params(config_item *cfg)
 124 {
 125     game_params *ret = snew(game_params);
 126
 127     ret->w = atoi(cfg[0].sval);
 128     ret->h = atoi(cfg[1].sval);
 129
 130     return ret;
 131 }
 132
 133 static char *validate_params(game_params *params)
 134 {
 135     if (params->w < 2 && params->h < 2)
 136         return "Width and height must both be at least two";
 137
 138     return NULL;
 139 }
 140
 141 static int perm_parity(int *perm, int n)
 142 {
 143     int i, j, ret;
 144
 145     ret = 0;
 146
 147     for (i = 0; i < n-1; i++)
 148         for (j = i+1; j < n; j++)
 149             if (perm[i] > perm[j])
 150                 ret = !ret;
 151
 152     return ret;
 153 }
 154
 155 static char *new_game_seed(game_params *params, random_state *rs)
 156 {
 157     int gap, n, i, x;
 158     int x1, x2, p1, p2, parity;
 159     int *tiles, *used;
 160     char *ret;
 161     int retlen;
 162
 163     n = params->w * params->h;
 164
 165     tiles = snewn(n, int);
 166     used = snewn(n, int);
 167
 168     for (i = 0; i < n; i++) {
 169         tiles[i] = -1;
 170         used[i] = FALSE;
 171     }
 172
 173     gap = random_upto(rs, n);
 174     tiles[gap] = 0;
 175     used[0] = TRUE;
 176
 177     /*
 178      * Place everything else except the last two tiles.
 179      */
 180     for (x = 0, i = n-1; i > 2; i--) {
 181         int k = random_upto(rs, i);
 182         int j;
 183
 184         for (j = 0; j < n; j++)
 185             if (!used[j] && (k-- == 0))
 186                 break;
 187
 188         assert(j < n && !used[j]);
 189         used[j] = TRUE;
 190
 191         while (tiles[x] >= 0)
 192             x++;
 193         assert(x < n);
 194         tiles[x] = j;
 195     }
 196
 197     /*
 198      * Find the last two locations, and the last two pieces.
 199      */
 200     while (tiles[x] >= 0)
 201         x++;
 202     assert(x < n);
 203     x1 = x;
 204     x++;
 205     while (tiles[x] >= 0)
 206         x++;
 207     assert(x < n);
 208     x2 = x;
 209
 210     for (i = 0; i < n; i++)
 211         if (!used[i])
 212             break;
 213     p1 = i;
 214     for (i = p1+1; i < n; i++)
 215         if (!used[i])
 216             break;
 217     p2 = i;
 218
 219     /*
 220      * Determine the required parity of the overall permutation.
 221      * This is the XOR of:
 222      *
 223      *  - The chessboard parity ((x^y)&1) of the gap square. The
 224      *    bottom right counts as even.
 225      *
 226      *  - The parity of n. (The target permutation is 1,...,n-1,0
 227      *    rather than 0,...,n-1; this is a cyclic permutation of
 228      *    the starting point and hence is odd iff n is even.)
 229      */
 230     parity = ((X(params, gap) - (params->w-1)) ^
 231               (Y(params, gap) - (params->h-1)) ^
 232               (n+1)) & 1;
 233
 234     /*
 235      * Try the last two tiles one way round. If that fails, swap
 236      * them.
 237      */
 238     tiles[x1] = p1;
 239     tiles[x2] = p2;
 240     if (perm_parity(tiles, n) != parity) {
 241         tiles[x1] = p2;
 242         tiles[x2] = p1;
 243         assert(perm_parity(tiles, n) == parity);
 244     }
 245
 246     /*
 247      * Now construct the game seed, by describing the tile array as
 248      * a simple sequence of comma-separated integers.
 249      */
 250     ret = NULL;
 251     retlen = 0;
 252     for (i = 0; i < n; i++) {
 253         char buf[80];
 254         int k;
 255
 256         k = sprintf(buf, "%d,", tiles[i]);
 257
 258         ret = sresize(ret, retlen + k + 1, char);
 259         strcpy(ret + retlen, buf);
 260         retlen += k;
 261     }
 262     ret[retlen-1] = '\0';              /* delete last comma */
 263
 264     sfree(tiles);
 265     sfree(used);
 266
 267     return ret;
 268 }
 269
 270 static char *validate_seed(game_params *params, char *seed)
 271 {
 272     char *p, *err;
 273     int i, area;
 274     int *used;
 275
 276     area = params->w * params->h;
 277     p = seed;
 278     err = NULL;
 279
 280     used = snewn(area, int);
 281     for (i = 0; i < area; i++)
 282         used[i] = FALSE;
 283
 284     for (i = 0; i < area; i++) {
 285         char *q = p;
 286         int n;
 287
 288         if (*p < '0' || *p > '9') {
 289             err = "Not enough numbers in string";
 290             goto leave;
 291         }
 292         while (*p >= '0' && *p <= '9')
 293             p++;
 294         if (i < area-1 && *p != ',') {
 295             err = "Expected comma after number";
 296             goto leave;
 297         }
 298         else if (i == area-1 && *p) {
 299             err = "Excess junk at end of string";
 300             goto leave;
 301         }
 302         n = atoi(q);
 303         if (n < 0 || n >= area) {
 304             err = "Number out of range";
 305             goto leave;
 306         }
 307         if (used[n]) {
 308             err = "Number used twice";
 309             goto leave;
 310         }
 311         used[n] = TRUE;
 312
 313         if (*p) p++;                   /* eat comma */
 314     }
 315
 316     leave:
 317     sfree(used);
 318     return err;
 319 }
 320
 321 static game_state *new_game(game_params *params, char *seed)
 322 {
 323     game_state *state = snew(game_state);
 324     int i;
 325     char *p;
 326
 327     state->w = params->w;
 328     state->h = params->h;
 329     state->n = params->w * params->h;
 330     state->tiles = snewn(state->n, int);
 331
 332     state->gap_pos = 0;
 333     p = seed;
 334     i = 0;
 335     for (i = 0; i < state->n; i++) {
 336         assert(*p);
 337         state->tiles[i] = atoi(p);
 338         if (state->tiles[i] == 0)
 339             state->gap_pos = i;
 340         while (*p && *p != ',')
 341             p++;
 342         if (*p) p++;                   /* eat comma */
 343     }
 344     assert(!*p);
 345     assert(state->tiles[state->gap_pos] == 0);
 346
 347     state->completed = state->movecount = 0;
 348
 349     return state;
 350 }
 351
 352 static game_state *dup_game(game_state *state)
 353 {
 354     game_state *ret = snew(game_state);
 355
 356     ret->w = state->w;
 357     ret->h = state->h;
 358     ret->n = state->n;
 359     ret->tiles = snewn(state->w * state->h, int);
 360     memcpy(ret->tiles, state->tiles, state->w * state->h * sizeof(int));
 361     ret->gap_pos = state->gap_pos;
 362     ret->completed = state->completed;
 363     ret->movecount = state->movecount;
 364
 365     return ret;
 366 }
 367
 368 static void free_game(game_state *state)
 369 {
 370     sfree(state);
 371 }
 372
 373 static game_ui *new_ui(game_state *state)
 374 {
 375     return NULL;
 376 }
 377
 378 static void free_ui(game_ui *ui)
 379 {
 380 }
 381
 382 static game_state *make_move(game_state *from, game_ui *ui,
 383                              int x, int y, int button)
 384 {
 385     int gx, gy, dx, dy, ux, uy, up, p;
 386     game_state *ret;
 387
 388     gx = X(from, from->gap_pos);
 389     gy = Y(from, from->gap_pos);
 390
 391     if (button == CURSOR_RIGHT && gx > 0)
 392         dx = gx - 1, dy = gy;
 393     else if (button == CURSOR_LEFT && gx < from->w-1)
 394         dx = gx + 1, dy = gy;
 395     else if (button == CURSOR_DOWN && gy > 0)
 396         dy = gy - 1, dx = gx;
 397     else if (button == CURSOR_UP && gy < from->h-1)
 398         dy = gy + 1, dx = gx;
 399     else if (button == LEFT_BUTTON) {
 400         dx = FROMCOORD(x);
 401         dy = FROMCOORD(y);
 402         if (dx < 0 || dx >= from->w || dy < 0 || dy >= from->h)
 403             return NULL;               /* out of bounds */
 404         /*
 405          * Any click location should be equal to the gap location
 406          * in _precisely_ one coordinate.
 407          */
 408         if ((dx == gx && dy == gy) || (dx != gx && dy != gy))
 409             return NULL;
 410     } else
 411         return NULL;                   /* no move */
 412
 413     /*
 414      * Find the unit displacement from the original gap
 415      * position towards this one.
 416      */
 417     ux = (dx < gx ? -1 : dx > gx ? +1 : 0);
 418     uy = (dy < gy ? -1 : dy > gy ? +1 : 0);
 419     up = C(from, ux, uy);
 420
 421     ret = dup_game(from);
 422
 423     ret->gap_pos = C(from, dx, dy);
 424     assert(ret->gap_pos >= 0 && ret->gap_pos < ret->n);
 425
 426     ret->tiles[ret->gap_pos] = 0;
 427
 428     for (p = from->gap_pos; p != ret->gap_pos; p += up) {
 429         assert(p >= 0 && p < from->n);
 430         ret->tiles[p] = from->tiles[p + up];
 431         ret->movecount++;
 432     }
 433
 434     /*
 435      * See if the game has been completed.
 436      */
 437     if (!ret->completed) {
 438         ret->completed = ret->movecount;
 439         for (p = 0; p < ret->n; p++)
 440             if (ret->tiles[p] != (p < ret->n-1 ? p+1 : 0))
 441                 ret->completed = 0;
 442     }
 443
 444     return ret;
 445 }
 446
 447 /* ----------------------------------------------------------------------
 448  * Drawing routines.
 449  */
 450
 451 struct game_drawstate {
 452     int started;
 453     int w, h, bgcolour;
 454     int *tiles;
 455 };
 456
 457 static void game_size(game_params *params, int *x, int *y)
 458 {
 459     *x = TILE_SIZE * params->w + 2 * BORDER;
 460     *y = TILE_SIZE * params->h + 2 * BORDER;
 461 }
 462
 463 static float *game_colours(frontend *fe, game_state *state, int *ncolours)
 464 {
 465     float *ret = snewn(3 * NCOLOURS, float);
 466     int i;
 467     float max;
 468
 469     frontend_default_colour(fe, &ret[COL_BACKGROUND * 3]);
 470
 471     /*
 472      * Drop the background colour so that the highlight is
 473      * noticeably brighter than it while still being under 1.
 474      */
 475     max = ret[COL_BACKGROUND*3];
 476     for (i = 1; i < 3; i++)
 477         if (ret[COL_BACKGROUND*3+i] > max)
 478             max = ret[COL_BACKGROUND*3+i];
 479     if (max * 1.2F > 1.0F) {
 480         for (i = 0; i < 3; i++)
 481             ret[COL_BACKGROUND*3+i] /= (max * 1.2F);
 482     }
 483
 484     for (i = 0; i < 3; i++) {
 485         ret[COL_HIGHLIGHT * 3 + i] = ret[COL_BACKGROUND * 3 + i] * 1.2F;
 486         ret[COL_LOWLIGHT * 3 + i] = ret[COL_BACKGROUND * 3 + i] * 0.8F;
 487         ret[COL_TEXT * 3 + i] = 0.0;
 488     }
 489
 490     *ncolours = NCOLOURS;
 491     return ret;
 492 }
 493
 494 static game_drawstate *game_new_drawstate(game_state *state)
 495 {
 496     struct game_drawstate *ds = snew(struct game_drawstate);
 497     int i;
 498
 499     ds->started = FALSE;
 500     ds->w = state->w;
 501     ds->h = state->h;
 502     ds->bgcolour = COL_BACKGROUND;
 503     ds->tiles = snewn(ds->w*ds->h, int);
 504     for (i = 0; i < ds->w*ds->h; i++)
 505         ds->tiles[i] = -1;
 506
 507     return ds;
 508 }
 509
 510 static void game_free_drawstate(game_drawstate *ds)
 511 {
 512     sfree(ds->tiles);
 513     sfree(ds);
 514 }
 515
 516 static void draw_tile(frontend *fe, game_state *state, int x, int y,
 517                       int tile, int flash_colour)
 518 {
 519     if (tile == 0) {
 520         draw_rect(fe, x, y, TILE_SIZE, TILE_SIZE,
 521                   flash_colour);
 522     } else {
 523         int coords[6];
 524         char str[40];
 525
 526         coords[0] = x + TILE_SIZE - 1;
 527         coords[1] = y + TILE_SIZE - 1;
 528         coords[2] = x + TILE_SIZE - 1;
 529         coords[3] = y;
 530         coords[4] = x;
 531         coords[5] = y + TILE_SIZE - 1;
 532         draw_polygon(fe, coords, 3, TRUE, COL_LOWLIGHT);
 533         draw_polygon(fe, coords, 3, FALSE, COL_LOWLIGHT);
 534
 535         coords[0] = x;
 536         coords[1] = y;
 537         draw_polygon(fe, coords, 3, TRUE, COL_HIGHLIGHT);
 538         draw_polygon(fe, coords, 3, FALSE, COL_HIGHLIGHT);
 539
 540         draw_rect(fe, x + HIGHLIGHT_WIDTH, y + HIGHLIGHT_WIDTH,
 541                   TILE_SIZE - 2*HIGHLIGHT_WIDTH, TILE_SIZE - 2*HIGHLIGHT_WIDTH,
 542                   flash_colour);
 543
 544         sprintf(str, "%d", tile);
 545         draw_text(fe, x + TILE_SIZE/2, y + TILE_SIZE/2,
 546                   FONT_VARIABLE, TILE_SIZE/3, ALIGN_VCENTRE | ALIGN_HCENTRE,
 547                   COL_TEXT, str);
 548     }
 549     draw_update(fe, x, y, TILE_SIZE, TILE_SIZE);
 550 }
 551
 552 static void game_redraw(frontend *fe, game_drawstate *ds, game_state *oldstate,
 553                  game_state *state, int dir, game_ui *ui,
 554                  float animtime, float flashtime)
 555 {
 556     int i, pass, bgcolour;
 557
 558     if (flashtime > 0) {
 559         int frame = (int)(flashtime / FLASH_FRAME);
 560         bgcolour = (frame % 2 ? COL_LOWLIGHT : COL_HIGHLIGHT);
 561     } else
 562         bgcolour = COL_BACKGROUND;
 563
 564     if (!ds->started) {
 565         int coords[6];
 566
 567         draw_rect(fe, 0, 0,
 568                   TILE_SIZE * state->w + 2 * BORDER,
 569                   TILE_SIZE * state->h + 2 * BORDER, COL_BACKGROUND);
 570         draw_update(fe, 0, 0,
 571                     TILE_SIZE * state->w + 2 * BORDER,
 572                     TILE_SIZE * state->h + 2 * BORDER);
 573
 574         /*
 575          * Recessed area containing the whole puzzle.
 576          */
 577         coords[0] = COORD(state->w) + HIGHLIGHT_WIDTH - 1;
 578         coords[1] = COORD(state->h) + HIGHLIGHT_WIDTH - 1;
 579         coords[2] = COORD(state->w) + HIGHLIGHT_WIDTH - 1;
 580         coords[3] = COORD(0) - HIGHLIGHT_WIDTH;
 581         coords[4] = COORD(0) - HIGHLIGHT_WIDTH;
 582         coords[5] = COORD(state->h) + HIGHLIGHT_WIDTH - 1;
 583         draw_polygon(fe, coords, 3, TRUE, COL_HIGHLIGHT);
 584         draw_polygon(fe, coords, 3, FALSE, COL_HIGHLIGHT);
 585
 586         coords[1] = COORD(0) - HIGHLIGHT_WIDTH;
 587         coords[0] = COORD(0) - HIGHLIGHT_WIDTH;
 588         draw_polygon(fe, coords, 3, TRUE, COL_LOWLIGHT);
 589         draw_polygon(fe, coords, 3, FALSE, COL_LOWLIGHT);
 590
 591         ds->started = TRUE;
 592     }
 593
 594     /*
 595      * Now draw each tile. We do this in two passes to make
 596      * animation easy.
 597      */
 598     for (pass = 0; pass < 2; pass++) {
 599         for (i = 0; i < state->n; i++) {
 600             int t, t0;
 601             /*
 602              * Figure out what should be displayed at this
 603              * location. It's either a simple tile, or it's a
 604              * transition between two tiles (in which case we say
 605              * -1 because it must always be drawn).
 606              */
 607
 608             if (oldstate && oldstate->tiles[i] != state->tiles[i])
 609                 t = -1;
 610             else
 611                 t = state->tiles[i];
 612
 613             t0 = t;
 614
 615             if (ds->bgcolour != bgcolour ||   /* always redraw when flashing */
 616                 ds->tiles[i] != t || ds->tiles[i] == -1 || t == -1) {
 617                 int x, y;
 618
 619                 /*
 620                  * Figure out what to _actually_ draw, and where to
 621                  * draw it.
 622                  */
 623                 if (t == -1) {
 624                     int x0, y0, x1, y1;
 625                     int j;
 626
 627                     /*
 628                      * On the first pass, just blank the tile.
 629                      */
 630                     if (pass == 0) {
 631                         x = COORD(X(state, i));
 632                         y = COORD(Y(state, i));
 633                         t = 0;
 634                     } else {
 635                         float c;
 636
 637                         t = state->tiles[i];
 638
 639                         /*
 640                          * Don't bother moving the gap; just don't
 641                          * draw it.
 642                          */
 643                         if (t == 0)
 644                             continue;
 645
 646                         /*
 647                          * Find the coordinates of this tile in the old and
 648                          * new states.
 649                          */
 650                         x1 = COORD(X(state, i));
 651                         y1 = COORD(Y(state, i));
 652                         for (j = 0; j < oldstate->n; j++)
 653                             if (oldstate->tiles[j] == state->tiles[i])
 654                                 break;
 655                         assert(j < oldstate->n);
 656                         x0 = COORD(X(state, j));
 657                         y0 = COORD(Y(state, j));
 658
 659                         c = (animtime / ANIM_TIME);
 660                         if (c < 0.0F) c = 0.0F;
 661                         if (c > 1.0F) c = 1.0F;
 662
 663                         x = x0 + (int)(c * (x1 - x0));
 664                         y = y0 + (int)(c * (y1 - y0));
 665                     }
 666
 667                 } else {
 668                     if (pass == 0)
 669                         continue;
 670                     x = COORD(X(state, i));
 671                     y = COORD(Y(state, i));
 672                 }
 673
 674                 draw_tile(fe, state, x, y, t, bgcolour);
 675             }
 676             ds->tiles[i] = t0;
 677         }
 678     }
 679     ds->bgcolour = bgcolour;
 680
 681     /*
 682      * Update the status bar.
 683      */
 684     {
 685         char statusbuf[256];
 686
 687         /*
 688          * Don't show the new status until we're also showing the
 689          * new _state_ - after the game animation is complete.
 690          */
 691         if (oldstate)
 692             state = oldstate;
 693
 694         sprintf(statusbuf, "%sMoves: %d",
 695                 (state->completed ? "COMPLETED! " : ""),
 696                 (state->completed ? state->completed : state->movecount));
 697
 698         status_bar(fe, statusbuf);
 699     }
 700 }
 701
 702 static float game_anim_length(game_state *oldstate,
 703                               game_state *newstate, int dir)
 704 {
 705     return ANIM_TIME;
 706 }
 707
 708 static float game_flash_length(game_state *oldstate,
 709                                game_state *newstate, int dir)
 710 {
 711     if (!oldstate->completed && newstate->completed)
 712         return 2 * FLASH_FRAME;
 713     else
 714         return 0.0F;
 715 }
 716
 717 static int game_wants_statusbar(void)
 718 {
 719     return TRUE;
 720 }
 721
 722 #ifdef COMBINED
 723 #define thegame fifteen
 724 #endif
 725
 726 const struct game thegame = {
 727     "Fifteen", "games.fifteen", TRUE,
 728     default_params,
 729     game_fetch_preset,
 730     decode_params,
 731     encode_params,
 732     free_params,
 733     dup_params,
 734     game_configure,
 735     custom_params,
 736     validate_params,
 737     new_game_seed,
 738     validate_seed,
 739     new_game,
 740     dup_game,
 741     free_game,
 742     new_ui,
 743     free_ui,
 744     make_move,
 745     game_size,
 746     game_colours,
 747     game_new_drawstate,
 748     game_free_drawstate,
 749     game_redraw,
 750     game_anim_length,
 751     game_flash_length,
 752     game_wants_statusbar,
 753 };