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