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 char *game_text_format(game_state *state)
 374 {
 375     return NULL;
 376 }
 377
 378 static game_ui *new_ui(game_state *state)
 379 {
 380     return NULL;
 381 }
 382
 383 static void free_ui(game_ui *ui)
 384 {
 385 }
 386
 387 static game_state *make_move(game_state *from, game_ui *ui,
 388                              int x, int y, int button)
 389 {
 390     int gx, gy, dx, dy, ux, uy, up, p;
 391     game_state *ret;
 392
 393     gx = X(from, from->gap_pos);
 394     gy = Y(from, from->gap_pos);
 395
 396     if (button == CURSOR_RIGHT && gx > 0)
 397         dx = gx - 1, dy = gy;
 398     else if (button == CURSOR_LEFT && gx < from->w-1)
 399         dx = gx + 1, dy = gy;
 400     else if (button == CURSOR_DOWN && gy > 0)
 401         dy = gy - 1, dx = gx;
 402     else if (button == CURSOR_UP && gy < from->h-1)
 403         dy = gy + 1, dx = gx;
 404     else if (button == LEFT_BUTTON) {
 405         dx = FROMCOORD(x);
 406         dy = FROMCOORD(y);
 407         if (dx < 0 || dx >= from->w || dy < 0 || dy >= from->h)
 408             return NULL;               /* out of bounds */
 409         /*
 410          * Any click location should be equal to the gap location
 411          * in _precisely_ one coordinate.
 412          */
 413         if ((dx == gx && dy == gy) || (dx != gx && dy != gy))
 414             return NULL;
 415     } else
 416         return NULL;                   /* no move */
 417
 418     /*
 419      * Find the unit displacement from the original gap
 420      * position towards this one.
 421      */
 422     ux = (dx < gx ? -1 : dx > gx ? +1 : 0);
 423     uy = (dy < gy ? -1 : dy > gy ? +1 : 0);
 424     up = C(from, ux, uy);
 425
 426     ret = dup_game(from);
 427
 428     ret->gap_pos = C(from, dx, dy);
 429     assert(ret->gap_pos >= 0 && ret->gap_pos < ret->n);
 430
 431     ret->tiles[ret->gap_pos] = 0;
 432
 433     for (p = from->gap_pos; p != ret->gap_pos; p += up) {
 434         assert(p >= 0 && p < from->n);
 435         ret->tiles[p] = from->tiles[p + up];
 436         ret->movecount++;
 437     }
 438
 439     /*
 440      * See if the game has been completed.
 441      */
 442     if (!ret->completed) {
 443         ret->completed = ret->movecount;
 444         for (p = 0; p < ret->n; p++)
 445             if (ret->tiles[p] != (p < ret->n-1 ? p+1 : 0))
 446                 ret->completed = 0;
 447     }
 448
 449     return ret;
 450 }
 451
 452 /* ----------------------------------------------------------------------
 453  * Drawing routines.
 454  */
 455
 456 struct game_drawstate {
 457     int started;
 458     int w, h, bgcolour;
 459     int *tiles;
 460 };
 461
 462 static void game_size(game_params *params, int *x, int *y)
 463 {
 464     *x = TILE_SIZE * params->w + 2 * BORDER;
 465     *y = TILE_SIZE * params->h + 2 * BORDER;
 466 }
 467
 468 static float *game_colours(frontend *fe, game_state *state, int *ncolours)
 469 {
 470     float *ret = snewn(3 * NCOLOURS, float);
 471     int i;
 472     float max;
 473
 474     frontend_default_colour(fe, &ret[COL_BACKGROUND * 3]);
 475
 476     /*
 477      * Drop the background colour so that the highlight is
 478      * noticeably brighter than it while still being under 1.
 479      */
 480     max = ret[COL_BACKGROUND*3];
 481     for (i = 1; i < 3; i++)
 482         if (ret[COL_BACKGROUND*3+i] > max)
 483             max = ret[COL_BACKGROUND*3+i];
 484     if (max * 1.2F > 1.0F) {
 485         for (i = 0; i < 3; i++)
 486             ret[COL_BACKGROUND*3+i] /= (max * 1.2F);
 487     }
 488
 489     for (i = 0; i < 3; i++) {
 490         ret[COL_HIGHLIGHT * 3 + i] = ret[COL_BACKGROUND * 3 + i] * 1.2F;
 491         ret[COL_LOWLIGHT * 3 + i] = ret[COL_BACKGROUND * 3 + i] * 0.8F;
 492         ret[COL_TEXT * 3 + i] = 0.0;
 493     }
 494
 495     *ncolours = NCOLOURS;
 496     return ret;
 497 }
 498
 499 static game_drawstate *game_new_drawstate(game_state *state)
 500 {
 501     struct game_drawstate *ds = snew(struct game_drawstate);
 502     int i;
 503
 504     ds->started = FALSE;
 505     ds->w = state->w;
 506     ds->h = state->h;
 507     ds->bgcolour = COL_BACKGROUND;
 508     ds->tiles = snewn(ds->w*ds->h, int);
 509     for (i = 0; i < ds->w*ds->h; i++)
 510         ds->tiles[i] = -1;
 511
 512     return ds;
 513 }
 514
 515 static void game_free_drawstate(game_drawstate *ds)
 516 {
 517     sfree(ds->tiles);
 518     sfree(ds);
 519 }
 520
 521 static void draw_tile(frontend *fe, game_state *state, int x, int y,
 522                       int tile, int flash_colour)
 523 {
 524     if (tile == 0) {
 525         draw_rect(fe, x, y, TILE_SIZE, TILE_SIZE,
 526                   flash_colour);
 527     } else {
 528         int coords[6];
 529         char str[40];
 530
 531         coords[0] = x + TILE_SIZE - 1;
 532         coords[1] = y + TILE_SIZE - 1;
 533         coords[2] = x + TILE_SIZE - 1;
 534         coords[3] = y;
 535         coords[4] = x;
 536         coords[5] = y + TILE_SIZE - 1;
 537         draw_polygon(fe, coords, 3, TRUE, COL_LOWLIGHT);
 538         draw_polygon(fe, coords, 3, FALSE, COL_LOWLIGHT);
 539
 540         coords[0] = x;
 541         coords[1] = y;
 542         draw_polygon(fe, coords, 3, TRUE, COL_HIGHLIGHT);
 543         draw_polygon(fe, coords, 3, FALSE, COL_HIGHLIGHT);
 544
 545         draw_rect(fe, x + HIGHLIGHT_WIDTH, y + HIGHLIGHT_WIDTH,
 546                   TILE_SIZE - 2*HIGHLIGHT_WIDTH, TILE_SIZE - 2*HIGHLIGHT_WIDTH,
 547                   flash_colour);
 548
 549         sprintf(str, "%d", tile);
 550         draw_text(fe, x + TILE_SIZE/2, y + TILE_SIZE/2,
 551                   FONT_VARIABLE, TILE_SIZE/3, ALIGN_VCENTRE | ALIGN_HCENTRE,
 552                   COL_TEXT, str);
 553     }
 554     draw_update(fe, x, y, TILE_SIZE, TILE_SIZE);
 555 }
 556
 557 static void game_redraw(frontend *fe, game_drawstate *ds, game_state *oldstate,
 558                  game_state *state, int dir, game_ui *ui,
 559                  float animtime, float flashtime)
 560 {
 561     int i, pass, bgcolour;
 562
 563     if (flashtime > 0) {
 564         int frame = (int)(flashtime / FLASH_FRAME);
 565         bgcolour = (frame % 2 ? COL_LOWLIGHT : COL_HIGHLIGHT);
 566     } else
 567         bgcolour = COL_BACKGROUND;
 568
 569     if (!ds->started) {
 570         int coords[6];
 571
 572         draw_rect(fe, 0, 0,
 573                   TILE_SIZE * state->w + 2 * BORDER,
 574                   TILE_SIZE * state->h + 2 * BORDER, COL_BACKGROUND);
 575         draw_update(fe, 0, 0,
 576                     TILE_SIZE * state->w + 2 * BORDER,
 577                     TILE_SIZE * state->h + 2 * BORDER);
 578
 579         /*
 580          * Recessed area containing the whole puzzle.
 581          */
 582         coords[0] = COORD(state->w) + HIGHLIGHT_WIDTH - 1;
 583         coords[1] = COORD(state->h) + HIGHLIGHT_WIDTH - 1;
 584         coords[2] = COORD(state->w) + HIGHLIGHT_WIDTH - 1;
 585         coords[3] = COORD(0) - HIGHLIGHT_WIDTH;
 586         coords[4] = COORD(0) - HIGHLIGHT_WIDTH;
 587         coords[5] = COORD(state->h) + HIGHLIGHT_WIDTH - 1;
 588         draw_polygon(fe, coords, 3, TRUE, COL_HIGHLIGHT);
 589         draw_polygon(fe, coords, 3, FALSE, COL_HIGHLIGHT);
 590
 591         coords[1] = COORD(0) - HIGHLIGHT_WIDTH;
 592         coords[0] = COORD(0) - HIGHLIGHT_WIDTH;
 593         draw_polygon(fe, coords, 3, TRUE, COL_LOWLIGHT);
 594         draw_polygon(fe, coords, 3, FALSE, COL_LOWLIGHT);
 595
 596         ds->started = TRUE;
 597     }
 598
 599     /*
 600      * Now draw each tile. We do this in two passes to make
 601      * animation easy.
 602      */
 603     for (pass = 0; pass < 2; pass++) {
 604         for (i = 0; i < state->n; i++) {
 605             int t, t0;
 606             /*
 607              * Figure out what should be displayed at this
 608              * location. It's either a simple tile, or it's a
 609              * transition between two tiles (in which case we say
 610              * -1 because it must always be drawn).
 611              */
 612
 613             if (oldstate && oldstate->tiles[i] != state->tiles[i])
 614                 t = -1;
 615             else
 616                 t = state->tiles[i];
 617
 618             t0 = t;
 619
 620             if (ds->bgcolour != bgcolour ||   /* always redraw when flashing */
 621                 ds->tiles[i] != t || ds->tiles[i] == -1 || t == -1) {
 622                 int x, y;
 623
 624                 /*
 625                  * Figure out what to _actually_ draw, and where to
 626                  * draw it.
 627                  */
 628                 if (t == -1) {
 629                     int x0, y0, x1, y1;
 630                     int j;
 631
 632                     /*
 633                      * On the first pass, just blank the tile.
 634                      */
 635                     if (pass == 0) {
 636                         x = COORD(X(state, i));
 637                         y = COORD(Y(state, i));
 638                         t = 0;
 639                     } else {
 640                         float c;
 641
 642                         t = state->tiles[i];
 643
 644                         /*
 645                          * Don't bother moving the gap; just don't
 646                          * draw it.
 647                          */
 648                         if (t == 0)
 649                             continue;
 650
 651                         /*
 652                          * Find the coordinates of this tile in the old and
 653                          * new states.
 654                          */
 655                         x1 = COORD(X(state, i));
 656                         y1 = COORD(Y(state, i));
 657                         for (j = 0; j < oldstate->n; j++)
 658                             if (oldstate->tiles[j] == state->tiles[i])
 659                                 break;
 660                         assert(j < oldstate->n);
 661                         x0 = COORD(X(state, j));
 662                         y0 = COORD(Y(state, j));
 663
 664                         c = (animtime / ANIM_TIME);
 665                         if (c < 0.0F) c = 0.0F;
 666                         if (c > 1.0F) c = 1.0F;
 667
 668                         x = x0 + (int)(c * (x1 - x0));
 669                         y = y0 + (int)(c * (y1 - y0));
 670                     }
 671
 672                 } else {
 673                     if (pass == 0)
 674                         continue;
 675                     x = COORD(X(state, i));
 676                     y = COORD(Y(state, i));
 677                 }
 678
 679                 draw_tile(fe, state, x, y, t, bgcolour);
 680             }
 681             ds->tiles[i] = t0;
 682         }
 683     }
 684     ds->bgcolour = bgcolour;
 685
 686     /*
 687      * Update the status bar.
 688      */
 689     {
 690         char statusbuf[256];
 691
 692         /*
 693          * Don't show the new status until we're also showing the
 694          * new _state_ - after the game animation is complete.
 695          */
 696         if (oldstate)
 697             state = oldstate;
 698
 699         sprintf(statusbuf, "%sMoves: %d",
 700                 (state->completed ? "COMPLETED! " : ""),
 701                 (state->completed ? state->completed : state->movecount));
 702
 703         status_bar(fe, statusbuf);
 704     }
 705 }
 706
 707 static float game_anim_length(game_state *oldstate,
 708                               game_state *newstate, int dir)
 709 {
 710     return ANIM_TIME;
 711 }
 712
 713 static float game_flash_length(game_state *oldstate,
 714                                game_state *newstate, int dir)
 715 {
 716     if (!oldstate->completed && newstate->completed)
 717         return 2 * FLASH_FRAME;
 718     else
 719         return 0.0F;
 720 }
 721
 722 static int game_wants_statusbar(void)
 723 {
 724     return TRUE;
 725 }
 726
 727 #ifdef COMBINED
 728 #define thegame fifteen
 729 #endif
 730
 731 const struct game thegame = {
 732     "Fifteen", "games.fifteen",
 733     default_params,
 734     game_fetch_preset,
 735     decode_params,
 736     encode_params,
 737     free_params,
 738     dup_params,
 739     TRUE, game_configure, custom_params,
 740     validate_params,
 741     new_game_seed,
 742     validate_seed,
 743     new_game,
 744     dup_game,
 745     free_game,
 746     FALSE, game_text_format,
 747     new_ui,
 748     free_ui,
 749     make_move,
 750     game_size,
 751     game_colours,
 752     game_new_drawstate,
 753     game_free_drawstate,
 754     game_redraw,
 755     game_anim_length,
 756     game_flash_length,
 757     game_wants_statusbar,
 758 };