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