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 PREFERRED_TILE_SIZE 48
  15 #define TILE_SIZE (ds->tilesize)
  16 #define BORDER    (TILE_SIZE / 2)
  17 #define HIGHLIGHT_WIDTH (TILE_SIZE / 20)
  18 #define COORD(x)  ( (x) * TILE_SIZE + BORDER )
  19 #define FROMCOORD(x)  ( ((x) - BORDER + TILE_SIZE) / TILE_SIZE - 1 )
  20
  21 #define ANIM_TIME 0.13F
  22 #define FLASH_FRAME 0.13F
  23
  24 #define X(state, i) ( (i) % (state)->w )
  25 #define Y(state, i) ( (i) / (state)->w )
  26 #define C(state, x, y) ( (y) * (state)->w + (x) )
  27
  28 enum {
  29     COL_BACKGROUND,
  30     COL_TEXT,
  31     COL_HIGHLIGHT,
  32     COL_LOWLIGHT,
  33     NCOLOURS
  34 };
  35
  36 struct game_params {
  37     int w, h;
  38 };
  39
  40 struct game_state {
  41     int w, h, n;
  42     int *tiles;
  43     int gap_pos;
  44     int completed;
  45     int used_solve;                    /* used to suppress completion flash */
  46     int movecount;
  47 };
  48
  49 static game_params *default_params(void)
  50 {
  51     game_params *ret = snew(game_params);
  52
  53     ret->w = ret->h = 4;
  54
  55     return ret;
  56 }
  57
  58 static int game_fetch_preset(int i, char **name, game_params **params)
  59 {
  60     return FALSE;
  61 }
  62
  63 static void free_params(game_params *params)
  64 {
  65     sfree(params);
  66 }
  67
  68 static game_params *dup_params(game_params *params)
  69 {
  70     game_params *ret = snew(game_params);
  71     *ret = *params;                    /* structure copy */
  72     return ret;
  73 }
  74
  75 static void decode_params(game_params *ret, char const *string)
  76 {
  77     ret->w = ret->h = atoi(string);
  78     while (*string && isdigit((unsigned char)*string)) string++;
  79     if (*string == 'x') {
  80         string++;
  81         ret->h = atoi(string);
  82     }
  83 }
  84
  85 static char *encode_params(game_params *params, int full)
  86 {
  87     char data[256];
  88
  89     sprintf(data, "%dx%d", params->w, params->h);
  90
  91     return dupstr(data);
  92 }
  93
  94 static config_item *game_configure(game_params *params)
  95 {
  96     config_item *ret;
  97     char buf[80];
  98
  99     ret = snewn(3, config_item);
 100
 101     ret[0].name = "Width";
 102     ret[0].type = C_STRING;
 103     sprintf(buf, "%d", params->w);
 104     ret[0].sval = dupstr(buf);
 105     ret[0].ival = 0;
 106
 107     ret[1].name = "Height";
 108     ret[1].type = C_STRING;
 109     sprintf(buf, "%d", params->h);
 110     ret[1].sval = dupstr(buf);
 111     ret[1].ival = 0;
 112
 113     ret[2].name = NULL;
 114     ret[2].type = C_END;
 115     ret[2].sval = NULL;
 116     ret[2].ival = 0;
 117
 118     return ret;
 119 }
 120
 121 static game_params *custom_params(config_item *cfg)
 122 {
 123     game_params *ret = snew(game_params);
 124
 125     ret->w = atoi(cfg[0].sval);
 126     ret->h = atoi(cfg[1].sval);
 127
 128     return ret;
 129 }
 130
 131 static char *validate_params(game_params *params, int full)
 132 {
 133     if (params->w < 2 || params->h < 2)
 134         return "Width and height must both be at least two";
 135
 136     return NULL;
 137 }
 138
 139 static int perm_parity(int *perm, int n)
 140 {
 141     int i, j, ret;
 142
 143     ret = 0;
 144
 145     for (i = 0; i < n-1; i++)
 146         for (j = i+1; j < n; j++)
 147             if (perm[i] > perm[j])
 148                 ret = !ret;
 149
 150     return ret;
 151 }
 152
 153 static char *new_game_desc(game_params *params, random_state *rs,
 154                            char **aux, int interactive)
 155 {
 156     int gap, n, i, x;
 157     int x1, x2, p1, p2, parity;
 158     int *tiles, *used;
 159     char *ret;
 160     int retlen;
 161
 162     n = params->w * params->h;
 163
 164     tiles = snewn(n, int);
 165     used = snewn(n, int);
 166
 167     for (i = 0; i < n; i++) {
 168         tiles[i] = -1;
 169         used[i] = FALSE;
 170     }
 171
 172     gap = random_upto(rs, n);
 173     tiles[gap] = 0;
 174     used[0] = TRUE;
 175
 176     /*
 177      * Place everything else except the last two tiles.
 178      */
 179     for (x = 0, i = n-1; i > 2; i--) {
 180         int k = random_upto(rs, i);
 181         int j;
 182
 183         for (j = 0; j < n; j++)
 184             if (!used[j] && (k-- == 0))
 185                 break;
 186
 187         assert(j < n && !used[j]);
 188         used[j] = TRUE;
 189
 190         while (tiles[x] >= 0)
 191             x++;
 192         assert(x < n);
 193         tiles[x] = j;
 194     }
 195
 196     /*
 197      * Find the last two locations, and the last two pieces.
 198      */
 199     while (tiles[x] >= 0)
 200         x++;
 201     assert(x < n);
 202     x1 = x;
 203     x++;
 204     while (tiles[x] >= 0)
 205         x++;
 206     assert(x < n);
 207     x2 = x;
 208
 209     for (i = 0; i < n; i++)
 210         if (!used[i])
 211             break;
 212     p1 = i;
 213     for (i = p1+1; i < n; i++)
 214         if (!used[i])
 215             break;
 216     p2 = i;
 217
 218     /*
 219      * Determine the required parity of the overall permutation.
 220      * This is the XOR of:
 221      *
 222      *  - The chessboard parity ((x^y)&1) of the gap square. The
 223      *    bottom right counts as even.
 224      *
 225      *  - The parity of n. (The target permutation is 1,...,n-1,0
 226      *    rather than 0,...,n-1; this is a cyclic permutation of
 227      *    the starting point and hence is odd iff n is even.)
 228      */
 229     parity = ((X(params, gap) - (params->w-1)) ^
 230               (Y(params, gap) - (params->h-1)) ^
 231               (n+1)) & 1;
 232
 233     /*
 234      * Try the last two tiles one way round. If that fails, swap
 235      * them.
 236      */
 237     tiles[x1] = p1;
 238     tiles[x2] = p2;
 239     if (perm_parity(tiles, n) != parity) {
 240         tiles[x1] = p2;
 241         tiles[x2] = p1;
 242         assert(perm_parity(tiles, n) == parity);
 243     }
 244
 245     /*
 246      * Now construct the game description, by describing the tile
 247      * array as a simple sequence of comma-separated integers.
 248      */
 249     ret = NULL;
 250     retlen = 0;
 251     for (i = 0; i < n; i++) {
 252         char buf[80];
 253         int k;
 254
 255         k = sprintf(buf, "%d,", tiles[i]);
 256
 257         ret = sresize(ret, retlen + k + 1, char);
 258         strcpy(ret + retlen, buf);
 259         retlen += k;
 260     }
 261     ret[retlen-1] = '\0';              /* delete last comma */
 262
 263     sfree(tiles);
 264     sfree(used);
 265
 266     return ret;
 267 }
 268
 269 static char *validate_desc(game_params *params, char *desc)
 270 {
 271     char *p, *err;
 272     int i, area;
 273     int *used;
 274
 275     area = params->w * params->h;
 276     p = desc;
 277     err = NULL;
 278
 279     used = snewn(area, int);
 280     for (i = 0; i < area; i++)
 281         used[i] = FALSE;
 282
 283     for (i = 0; i < area; i++) {
 284         char *q = p;
 285         int n;
 286
 287         if (*p < '0' || *p > '9') {
 288             err = "Not enough numbers in string";
 289             goto leave;
 290         }
 291         while (*p >= '0' && *p <= '9')
 292             p++;
 293         if (i < area-1 && *p != ',') {
 294             err = "Expected comma after number";
 295             goto leave;
 296         }
 297         else if (i == area-1 && *p) {
 298             err = "Excess junk at end of string";
 299             goto leave;
 300         }
 301         n = atoi(q);
 302         if (n < 0 || n >= area) {
 303             err = "Number out of range";
 304             goto leave;
 305         }
 306         if (used[n]) {
 307             err = "Number used twice";
 308             goto leave;
 309         }
 310         used[n] = TRUE;
 311
 312         if (*p) p++;                   /* eat comma */
 313     }
 314
 315     leave:
 316     sfree(used);
 317     return err;
 318 }
 319
 320 static game_state *new_game(midend *me, game_params *params, char *desc)
 321 {
 322     game_state *state = snew(game_state);
 323     int i;
 324     char *p;
 325
 326     state->w = params->w;
 327     state->h = params->h;
 328     state->n = params->w * params->h;
 329     state->tiles = snewn(state->n, int);
 330
 331     state->gap_pos = 0;
 332     p = desc;
 333     i = 0;
 334     for (i = 0; i < state->n; i++) {
 335         assert(*p);
 336         state->tiles[i] = atoi(p);
 337         if (state->tiles[i] == 0)
 338             state->gap_pos = i;
 339         while (*p && *p != ',')
 340             p++;
 341         if (*p) p++;                   /* eat comma */
 342     }
 343     assert(!*p);
 344     assert(state->tiles[state->gap_pos] == 0);
 345
 346     state->completed = state->movecount = 0;
 347     state->used_solve = FALSE;
 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     ret->used_solve = state->used_solve;
 365
 366     return ret;
 367 }
 368
 369 static void free_game(game_state *state)
 370 {
 371     sfree(state->tiles);
 372     sfree(state);
 373 }
 374
 375 static char *solve_game(game_state *state, game_state *currstate,
 376                         char *aux, char **error)
 377 {
 378     return dupstr("S");
 379 }
 380
 381 static char *game_text_format(game_state *state)
 382 {
 383     char *ret, *p, buf[80];
 384     int x, y, col, maxlen;
 385
 386     /*
 387      * First work out how many characters we need to display each
 388      * number.
 389      */
 390     col = sprintf(buf, "%d", state->n-1);
 391
 392     /*
 393      * Now we know the exact total size of the grid we're going to
 394      * produce: it's got h rows, each containing w lots of col, w-1
 395      * spaces and a trailing newline.
 396      */
 397     maxlen = state->h * state->w * (col+1);
 398
 399     ret = snewn(maxlen+1, char);
 400     p = ret;
 401
 402     for (y = 0; y < state->h; y++) {
 403         for (x = 0; x < state->w; x++) {
 404             int v = state->tiles[state->w*y+x];
 405             if (v == 0)
 406                 sprintf(buf, "%*s", col, "");
 407             else
 408                 sprintf(buf, "%*d", col, v);
 409             memcpy(p, buf, col);
 410             p += col;
 411             if (x+1 == state->w)
 412                 *p++ = '\n';
 413             else
 414                 *p++ = ' ';
 415         }
 416     }
 417
 418     assert(p - ret == maxlen);
 419     *p = '\0';
 420     return ret;
 421 }
 422
 423 static game_ui *new_ui(game_state *state)
 424 {
 425     return NULL;
 426 }
 427
 428 static void free_ui(game_ui *ui)
 429 {
 430 }
 431
 432 static char *encode_ui(game_ui *ui)
 433 {
 434     return NULL;
 435 }
 436
 437 static void decode_ui(game_ui *ui, char *encoding)
 438 {
 439 }
 440
 441 static void game_changed_state(game_ui *ui, game_state *oldstate,
 442                                game_state *newstate)
 443 {
 444 }
 445
 446 struct game_drawstate {
 447     int started;
 448     int w, h, bgcolour;
 449     int *tiles;
 450     int tilesize;
 451 };
 452
 453 static char *interpret_move(game_state *state, game_ui *ui, game_drawstate *ds,
 454                             int x, int y, int button)
 455 {
 456     int gx, gy, dx, dy;
 457     char buf[80];
 458
 459     button &= ~MOD_MASK;
 460
 461     gx = X(state, state->gap_pos);
 462     gy = Y(state, state->gap_pos);
 463
 464     if (button == CURSOR_RIGHT && gx > 0)
 465         dx = gx - 1, dy = gy;
 466     else if (button == CURSOR_LEFT && gx < state->w-1)
 467         dx = gx + 1, dy = gy;
 468     else if (button == CURSOR_DOWN && gy > 0)
 469         dy = gy - 1, dx = gx;
 470     else if (button == CURSOR_UP && gy < state->h-1)
 471         dy = gy + 1, dx = gx;
 472     else if (button == LEFT_BUTTON) {
 473         dx = FROMCOORD(x);
 474         dy = FROMCOORD(y);
 475         if (dx < 0 || dx >= state->w || dy < 0 || dy >= state->h)
 476             return NULL;               /* out of bounds */
 477         /*
 478          * Any click location should be equal to the gap location
 479          * in _precisely_ one coordinate.
 480          */
 481         if ((dx == gx && dy == gy) || (dx != gx && dy != gy))
 482             return NULL;
 483     } else
 484         return NULL;                   /* no move */
 485
 486     sprintf(buf, "M%d,%d", dx, dy);
 487     return dupstr(buf);
 488 }
 489
 490 static game_state *execute_move(game_state *from, char *move)
 491 {
 492     int gx, gy, dx, dy, ux, uy, up, p;
 493     game_state *ret;
 494
 495     if (!strcmp(move, "S")) {
 496         int i;
 497
 498         ret = dup_game(from);
 499
 500         /*
 501          * Simply replace the grid with a solved one. For this game,
 502          * this isn't a useful operation for actually telling the user
 503          * what they should have done, but it is useful for
 504          * conveniently being able to get hold of a clean state from
 505          * which to practise manoeuvres.
 506          */
 507         for (i = 0; i < ret->n; i++)
 508             ret->tiles[i] = (i+1) % ret->n;
 509         ret->gap_pos = ret->n-1;
 510         ret->used_solve = TRUE;
 511         ret->completed = ret->movecount = 1;
 512
 513         return ret;
 514     }
 515
 516     gx = X(from, from->gap_pos);
 517     gy = Y(from, from->gap_pos);
 518
 519     if (move[0] != 'M' ||
 520         sscanf(move+1, "%d,%d", &dx, &dy) != 2 ||
 521         (dx == gx && dy == gy) || (dx != gx && dy != gy) ||
 522         dx < 0 || dx >= from->w || dy < 0 || dy >= from->h)
 523         return NULL;
 524
 525     /*
 526      * Find the unit displacement from the original gap
 527      * position towards this one.
 528      */
 529     ux = (dx < gx ? -1 : dx > gx ? +1 : 0);
 530     uy = (dy < gy ? -1 : dy > gy ? +1 : 0);
 531     up = C(from, ux, uy);
 532
 533     ret = dup_game(from);
 534
 535     ret->gap_pos = C(from, dx, dy);
 536     assert(ret->gap_pos >= 0 && ret->gap_pos < ret->n);
 537
 538     ret->tiles[ret->gap_pos] = 0;
 539
 540     for (p = from->gap_pos; p != ret->gap_pos; p += up) {
 541         assert(p >= 0 && p < from->n);
 542         ret->tiles[p] = from->tiles[p + up];
 543         ret->movecount++;
 544     }
 545
 546     /*
 547      * See if the game has been completed.
 548      */
 549     if (!ret->completed) {
 550         ret->completed = ret->movecount;
 551         for (p = 0; p < ret->n; p++)
 552             if (ret->tiles[p] != (p < ret->n-1 ? p+1 : 0))
 553                 ret->completed = 0;
 554     }
 555
 556     return ret;
 557 }
 558
 559 /* ----------------------------------------------------------------------
 560  * Drawing routines.
 561  */
 562
 563 static void game_compute_size(game_params *params, int tilesize,
 564                               int *x, int *y)
 565 {
 566     /* Ick: fake up `ds->tilesize' for macro expansion purposes */
 567     struct { int tilesize; } ads, *ds = &ads;
 568     ads.tilesize = tilesize;
 569
 570     *x = TILE_SIZE * params->w + 2 * BORDER;
 571     *y = TILE_SIZE * params->h + 2 * BORDER;
 572 }
 573
 574 static void game_set_size(drawing *dr, game_drawstate *ds,
 575                           game_params *params, int tilesize)
 576 {
 577     ds->tilesize = tilesize;
 578 }
 579
 580 static float *game_colours(frontend *fe, int *ncolours)
 581 {
 582     float *ret = snewn(3 * NCOLOURS, float);
 583     int i;
 584
 585     game_mkhighlight(fe, ret, COL_BACKGROUND, COL_HIGHLIGHT, COL_LOWLIGHT);
 586
 587     for (i = 0; i < 3; i++)
 588         ret[COL_TEXT * 3 + i] = 0.0;
 589
 590     *ncolours = NCOLOURS;
 591     return ret;
 592 }
 593
 594 static game_drawstate *game_new_drawstate(drawing *dr, game_state *state)
 595 {
 596     struct game_drawstate *ds = snew(struct game_drawstate);
 597     int i;
 598
 599     ds->started = FALSE;
 600     ds->w = state->w;
 601     ds->h = state->h;
 602     ds->bgcolour = COL_BACKGROUND;
 603     ds->tiles = snewn(ds->w*ds->h, int);
 604     ds->tilesize = 0;                  /* haven't decided yet */
 605     for (i = 0; i < ds->w*ds->h; i++)
 606         ds->tiles[i] = -1;
 607
 608     return ds;
 609 }
 610
 611 static void game_free_drawstate(drawing *dr, game_drawstate *ds)
 612 {
 613     sfree(ds->tiles);
 614     sfree(ds);
 615 }
 616
 617 static void draw_tile(drawing *dr, game_drawstate *ds, game_state *state,
 618                       int x, int y, int tile, int flash_colour)
 619 {
 620     if (tile == 0) {
 621         draw_rect(dr, x, y, TILE_SIZE, TILE_SIZE,
 622                   flash_colour);
 623     } else {
 624         int coords[6];
 625         char str[40];
 626
 627         coords[0] = x + TILE_SIZE - 1;
 628         coords[1] = y + TILE_SIZE - 1;
 629         coords[2] = x + TILE_SIZE - 1;
 630         coords[3] = y;
 631         coords[4] = x;
 632         coords[5] = y + TILE_SIZE - 1;
 633         draw_polygon(dr, coords, 3, COL_LOWLIGHT, COL_LOWLIGHT);
 634
 635         coords[0] = x;
 636         coords[1] = y;
 637         draw_polygon(dr, coords, 3, COL_HIGHLIGHT, COL_HIGHLIGHT);
 638
 639         draw_rect(dr, x + HIGHLIGHT_WIDTH, y + HIGHLIGHT_WIDTH,
 640                   TILE_SIZE - 2*HIGHLIGHT_WIDTH, TILE_SIZE - 2*HIGHLIGHT_WIDTH,
 641                   flash_colour);
 642
 643         sprintf(str, "%d", tile);
 644         draw_text(dr, x + TILE_SIZE/2, y + TILE_SIZE/2,
 645                   FONT_VARIABLE, TILE_SIZE/3, ALIGN_VCENTRE | ALIGN_HCENTRE,
 646                   COL_TEXT, str);
 647     }
 648     draw_update(dr, x, y, TILE_SIZE, TILE_SIZE);
 649 }
 650
 651 static void game_redraw(drawing *dr, game_drawstate *ds, game_state *oldstate,
 652                  game_state *state, int dir, game_ui *ui,
 653                  float animtime, float flashtime)
 654 {
 655     int i, pass, bgcolour;
 656
 657     if (flashtime > 0) {
 658         int frame = (int)(flashtime / FLASH_FRAME);
 659         bgcolour = (frame % 2 ? COL_LOWLIGHT : COL_HIGHLIGHT);
 660     } else
 661         bgcolour = COL_BACKGROUND;
 662
 663     if (!ds->started) {
 664         int coords[10];
 665
 666         draw_rect(dr, 0, 0,
 667                   TILE_SIZE * state->w + 2 * BORDER,
 668                   TILE_SIZE * state->h + 2 * BORDER, COL_BACKGROUND);
 669         draw_update(dr, 0, 0,
 670                     TILE_SIZE * state->w + 2 * BORDER,
 671                     TILE_SIZE * state->h + 2 * BORDER);
 672
 673         /*
 674          * Recessed area containing the whole puzzle.
 675          */
 676         coords[0] = COORD(state->w) + HIGHLIGHT_WIDTH - 1;
 677         coords[1] = COORD(state->h) + HIGHLIGHT_WIDTH - 1;
 678         coords[2] = COORD(state->w) + HIGHLIGHT_WIDTH - 1;
 679         coords[3] = COORD(0) - HIGHLIGHT_WIDTH;
 680         coords[4] = coords[2] - TILE_SIZE;
 681         coords[5] = coords[3] + TILE_SIZE;
 682         coords[8] = COORD(0) - HIGHLIGHT_WIDTH;
 683         coords[9] = COORD(state->h) + HIGHLIGHT_WIDTH - 1;
 684         coords[6] = coords[8] + TILE_SIZE;
 685         coords[7] = coords[9] - TILE_SIZE;
 686         draw_polygon(dr, coords, 5, COL_HIGHLIGHT, COL_HIGHLIGHT);
 687
 688         coords[1] = COORD(0) - HIGHLIGHT_WIDTH;
 689         coords[0] = COORD(0) - HIGHLIGHT_WIDTH;
 690         draw_polygon(dr, coords, 5, COL_LOWLIGHT, COL_LOWLIGHT);
 691
 692         ds->started = TRUE;
 693     }
 694
 695     /*
 696      * Now draw each tile. We do this in two passes to make
 697      * animation easy.
 698      */
 699     for (pass = 0; pass < 2; pass++) {
 700         for (i = 0; i < state->n; i++) {
 701             int t, t0;
 702             /*
 703              * Figure out what should be displayed at this
 704              * location. It's either a simple tile, or it's a
 705              * transition between two tiles (in which case we say
 706              * -1 because it must always be drawn).
 707              */
 708
 709             if (oldstate && oldstate->tiles[i] != state->tiles[i])
 710                 t = -1;
 711             else
 712                 t = state->tiles[i];
 713
 714             t0 = t;
 715
 716             if (ds->bgcolour != bgcolour ||   /* always redraw when flashing */
 717                 ds->tiles[i] != t || ds->tiles[i] == -1 || t == -1) {
 718                 int x, y;
 719
 720                 /*
 721                  * Figure out what to _actually_ draw, and where to
 722                  * draw it.
 723                  */
 724                 if (t == -1) {
 725                     int x0, y0, x1, y1;
 726                     int j;
 727
 728                     /*
 729                      * On the first pass, just blank the tile.
 730                      */
 731                     if (pass == 0) {
 732                         x = COORD(X(state, i));
 733                         y = COORD(Y(state, i));
 734                         t = 0;
 735                     } else {
 736                         float c;
 737
 738                         t = state->tiles[i];
 739
 740                         /*
 741                          * Don't bother moving the gap; just don't
 742                          * draw it.
 743                          */
 744                         if (t == 0)
 745                             continue;
 746
 747                         /*
 748                          * Find the coordinates of this tile in the old and
 749                          * new states.
 750                          */
 751                         x1 = COORD(X(state, i));
 752                         y1 = COORD(Y(state, i));
 753                         for (j = 0; j < oldstate->n; j++)
 754                             if (oldstate->tiles[j] == state->tiles[i])
 755                                 break;
 756                         assert(j < oldstate->n);
 757                         x0 = COORD(X(state, j));
 758                         y0 = COORD(Y(state, j));
 759
 760                         c = (animtime / ANIM_TIME);
 761                         if (c < 0.0F) c = 0.0F;
 762                         if (c > 1.0F) c = 1.0F;
 763
 764                         x = x0 + (int)(c * (x1 - x0));
 765                         y = y0 + (int)(c * (y1 - y0));
 766                     }
 767
 768                 } else {
 769                     if (pass == 0)
 770                         continue;
 771                     x = COORD(X(state, i));
 772                     y = COORD(Y(state, i));
 773                 }
 774
 775                 draw_tile(dr, ds, state, x, y, t, bgcolour);
 776             }
 777             ds->tiles[i] = t0;
 778         }
 779     }
 780     ds->bgcolour = bgcolour;
 781
 782     /*
 783      * Update the status bar.
 784      */
 785     {
 786         char statusbuf[256];
 787
 788         /*
 789          * Don't show the new status until we're also showing the
 790          * new _state_ - after the game animation is complete.
 791          */
 792         if (oldstate)
 793             state = oldstate;
 794
 795         if (state->used_solve)
 796             sprintf(statusbuf, "Moves since auto-solve: %d",
 797                     state->movecount - state->completed);
 798         else
 799             sprintf(statusbuf, "%sMoves: %d",
 800                     (state->completed ? "COMPLETED! " : ""),
 801                     (state->completed ? state->completed : state->movecount));
 802
 803         status_bar(dr, statusbuf);
 804     }
 805 }
 806
 807 static float game_anim_length(game_state *oldstate,
 808                               game_state *newstate, int dir, game_ui *ui)
 809 {
 810     return ANIM_TIME;
 811 }
 812
 813 static float game_flash_length(game_state *oldstate,
 814                                game_state *newstate, int dir, game_ui *ui)
 815 {
 816     if (!oldstate->completed && newstate->completed &&
 817         !oldstate->used_solve && !newstate->used_solve)
 818         return 2 * FLASH_FRAME;
 819     else
 820         return 0.0F;
 821 }
 822
 823 static int game_timing_state(game_state *state, game_ui *ui)
 824 {
 825     return TRUE;
 826 }
 827
 828 static void game_print_size(game_params *params, float *x, float *y)
 829 {
 830 }
 831
 832 static void game_print(drawing *dr, game_state *state, int tilesize)
 833 {
 834 }
 835
 836 #ifdef COMBINED
 837 #define thegame fifteen
 838 #endif
 839
 840 const struct game thegame = {
 841     "Fifteen", "games.fifteen", "fifteen",
 842     default_params,
 843     game_fetch_preset,
 844     decode_params,
 845     encode_params,
 846     free_params,
 847     dup_params,
 848     TRUE, game_configure, custom_params,
 849     validate_params,
 850     new_game_desc,
 851     validate_desc,
 852     new_game,
 853     dup_game,
 854     free_game,
 855     TRUE, solve_game,
 856     TRUE, game_text_format,
 857     new_ui,
 858     free_ui,
 859     encode_ui,
 860     decode_ui,
 861     game_changed_state,
 862     interpret_move,
 863     execute_move,
 864     PREFERRED_TILE_SIZE, game_compute_size, game_set_size,
 865     game_colours,
 866     game_new_drawstate,
 867     game_free_drawstate,
 868     game_redraw,
 869     game_anim_length,
 870     game_flash_length,
 871     FALSE, FALSE, game_print_size, game_print,
 872     TRUE,                              /* wants_statusbar */
 873     FALSE, game_timing_state,
 874     0,                                 /* flags */
 875 };