15 #define PI 3.141592653589793238462643383279502884197169399
17 #define MATMUL(xr,yr,m,x,y) do { \
18 float rx, ry, xx = (x), yy = (y), *mat = (m); \
19 rx = mat[0] * xx + mat[2] * yy; \
20 ry = mat[1] * xx + mat[3] * yy; \
21 (xr) = rx; (yr) = ry; \
24 /* Direction and other bitfields */
31 /* Corner flags go in the barriers array */
37 /* Rotations: Anticlockwise, Clockwise, Flip, general rotate */
38 #define A(x) ( (((x) & 0x07) << 1) | (((x) & 0x08) >> 3) )
39 #define C(x) ( (((x) & 0x0E) >> 1) | (((x) & 0x01) << 3) )
40 #define F(x) ( (((x) & 0x0C) >> 2) | (((x) & 0x03) << 2) )
41 #define ROT(x, n) ( ((n)&3) == 0 ? (x) : \
42 ((n)&3) == 1 ? A(x) : \
43 ((n)&3) == 2 ? F(x) : C(x) )
45 /* X and Y displacements */
46 #define X(x) ( (x) == R ? +1 : (x) == L ? -1 : 0 )
47 #define Y(x) ( (x) == D ? +1 : (x) == U ? -1 : 0 )
50 #define COUNT(x) ( (((x) & 0x08) >> 3) + (((x) & 0x04) >> 2) + \
51 (((x) & 0x02) >> 1) + ((x) & 0x01) )
55 #define WINDOW_OFFSET 16
57 #define ROTATE_TIME 0.13F
58 #define FLASH_FRAME 0.07F
76 float barrier_probability;
79 struct game_aux_info {
85 int width, height, cx, cy, wrapping, completed;
86 int last_rotate_x, last_rotate_y, last_rotate_dir;
87 int used_solve, just_used_solve;
89 unsigned char *barriers;
92 #define OFFSETWH(x2,y2,x1,y1,dir,width,height) \
93 ( (x2) = ((x1) + width + X((dir))) % width, \
94 (y2) = ((y1) + height + Y((dir))) % height)
96 #define OFFSET(x2,y2,x1,y1,dir,state) \
97 OFFSETWH(x2,y2,x1,y1,dir,(state)->width,(state)->height)
99 #define index(state, a, x, y) ( a[(y) * (state)->width + (x)] )
100 #define tile(state, x, y) index(state, (state)->tiles, x, y)
101 #define barrier(state, x, y) index(state, (state)->barriers, x, y)
107 static int xyd_cmp(const void *av, const void *bv) {
108 const struct xyd *a = (const struct xyd *)av;
109 const struct xyd *b = (const struct xyd *)bv;
118 if (a->direction < b->direction)
120 if (a->direction > b->direction)
125 static int xyd_cmp_nc(void *av, void *bv) { return xyd_cmp(av, bv); }
127 static struct xyd *new_xyd(int x, int y, int direction)
129 struct xyd *xyd = snew(struct xyd);
132 xyd->direction = direction;
136 /* ----------------------------------------------------------------------
137 * Manage game parameters.
139 static game_params *default_params(void)
141 game_params *ret = snew(game_params);
145 ret->wrapping = FALSE;
147 ret->barrier_probability = 0.0;
152 static int game_fetch_preset(int i, char **name, game_params **params)
156 static const struct { int x, y, wrap; } values[] = {
169 if (i < 0 || i >= lenof(values))
172 ret = snew(game_params);
173 ret->width = values[i].x;
174 ret->height = values[i].y;
175 ret->wrapping = values[i].wrap;
177 ret->barrier_probability = 0.0;
179 sprintf(str, "%dx%d%s", ret->width, ret->height,
180 ret->wrapping ? " wrapping" : "");
187 static void free_params(game_params *params)
192 static game_params *dup_params(game_params *params)
194 game_params *ret = snew(game_params);
195 *ret = *params; /* structure copy */
199 static void decode_params(game_params *ret, char const *string)
201 char const *p = string;
203 ret->width = atoi(p);
204 while (*p && isdigit((unsigned char)*p)) p++;
207 ret->height = atoi(p);
208 while (*p && isdigit((unsigned char)*p)) p++;
210 ret->height = ret->width;
216 ret->wrapping = TRUE;
217 } else if (*p == 'b') {
219 ret->barrier_probability = atof(p);
220 while (*p && (*p == '.' || isdigit((unsigned char)*p))) p++;
221 } else if (*p == 'a') {
225 p++; /* skip any other gunk */
229 static char *encode_params(game_params *params, int full)
234 len = sprintf(ret, "%dx%d", params->width, params->height);
235 if (params->wrapping)
237 if (full && params->barrier_probability)
238 len += sprintf(ret+len, "b%g", params->barrier_probability);
239 if (full && !params->unique)
241 assert(len < lenof(ret));
247 static config_item *game_configure(game_params *params)
252 ret = snewn(6, config_item);
254 ret[0].name = "Width";
255 ret[0].type = C_STRING;
256 sprintf(buf, "%d", params->width);
257 ret[0].sval = dupstr(buf);
260 ret[1].name = "Height";
261 ret[1].type = C_STRING;
262 sprintf(buf, "%d", params->height);
263 ret[1].sval = dupstr(buf);
266 ret[2].name = "Walls wrap around";
267 ret[2].type = C_BOOLEAN;
269 ret[2].ival = params->wrapping;
271 ret[3].name = "Barrier probability";
272 ret[3].type = C_STRING;
273 sprintf(buf, "%g", params->barrier_probability);
274 ret[3].sval = dupstr(buf);
277 ret[4].name = "Ensure unique solution";
278 ret[4].type = C_BOOLEAN;
280 ret[4].ival = params->unique;
290 static game_params *custom_params(config_item *cfg)
292 game_params *ret = snew(game_params);
294 ret->width = atoi(cfg[0].sval);
295 ret->height = atoi(cfg[1].sval);
296 ret->wrapping = cfg[2].ival;
297 ret->barrier_probability = (float)atof(cfg[3].sval);
298 ret->unique = cfg[4].ival;
303 static char *validate_params(game_params *params)
305 if (params->width <= 0 && params->height <= 0)
306 return "Width and height must both be greater than zero";
307 if (params->width <= 0)
308 return "Width must be greater than zero";
309 if (params->height <= 0)
310 return "Height must be greater than zero";
311 if (params->width <= 1 && params->height <= 1)
312 return "At least one of width and height must be greater than one";
313 if (params->barrier_probability < 0)
314 return "Barrier probability may not be negative";
315 if (params->barrier_probability > 1)
316 return "Barrier probability may not be greater than 1";
319 * Specifying either grid dimension as 2 in a wrapping puzzle
320 * makes it actually impossible to ensure a unique puzzle
325 * Without loss of generality, let us assume the puzzle _width_
326 * is 2, so we can conveniently discuss rows without having to
327 * say `rows/columns' all the time. (The height may be 2 as
328 * well, but that doesn't matter.)
330 * In each row, there are two edges between tiles: the inner
331 * edge (running down the centre of the grid) and the outer
332 * edge (the identified left and right edges of the grid).
334 * Lemma: In any valid 2xn puzzle there must be at least one
335 * row in which _exactly one_ of the inner edge and outer edge
338 * Proof: No row can have _both_ inner and outer edges
339 * connected, because this would yield a loop. So the only
340 * other way to falsify the lemma is for every row to have
341 * _neither_ the inner nor outer edge connected. But this
342 * means there is no connection at all between the left and
343 * right columns of the puzzle, so there are two disjoint
344 * subgraphs, which is also disallowed. []
346 * Given such a row, it is always possible to make the
347 * disconnected edge connected and the connected edge
348 * disconnected without changing the state of any other edge.
349 * (This is easily seen by case analysis on the various tiles:
350 * left-pointing and right-pointing endpoints can be exchanged,
351 * likewise T-pieces, and a corner piece can select its
352 * horizontal connectivity independently of its vertical.) This
353 * yields a distinct valid solution.
355 * Thus, for _every_ row in which exactly one of the inner and
356 * outer edge is connected, there are two valid states for that
357 * row, and hence the total number of solutions of the puzzle
358 * is at least 2^(number of such rows), and in particular is at
359 * least 2 since there must be at least one such row. []
361 if (params->unique && params->wrapping &&
362 (params->width == 2 || params->height == 2))
363 return "No wrapping puzzle with a width or height of 2 can have"
364 " a unique solution";
369 /* ----------------------------------------------------------------------
370 * Solver used to assure solution uniqueness during generation.
374 * Test cases I used while debugging all this were
376 * ./net --generate 1 13x11w#12300
377 * which expands under the non-unique grid generation rules to
378 * 13x11w:5eaade1bd222664436d5e2965c12656b1129dd825219e3274d558d5eb2dab5da18898e571d5a2987be79746bd95726c597447d6da96188c513add829da7681da954db113d3cd244
379 * and has two ambiguous areas.
381 * An even better one is
382 * 13x11w#507896411361192
384 * 13x11w:b7125b1aec598eb31bd58d82572bc11494e5dee4e8db2bdd29b88d41a16bdd996d2996ddec8c83741a1e8674e78328ba71737b8894a9271b1cd1399453d1952e43951d9b712822e
385 * and has an ambiguous area _and_ a situation where loop avoidance
386 * is a necessary deductive technique.
389 * 48x25w#820543338195187
391 * 48x25w:255989d14cdd185deaa753a93821a12edc1ab97943ac127e2685d7b8b3c48861b2192416139212b316eddd35de43714ebc7628d753db32e596284d9ec52c5a7dc1b4c811a655117d16dc28921b2b4161352cab1d89d18bc836b8b891d55ea4622a1251861b5bc9a8aa3e5bcd745c95229ca6c3b5e21d5832d397e917325793d7eb442dc351b2db2a52ba8e1651642275842d8871d5534aabc6d5b741aaa2d48ed2a7dbbb3151ddb49d5b9a7ed1ab98ee75d613d656dbba347bc514c84556b43a9bc65a3256ead792488b862a9d2a8a39b4255a4949ed7dbd79443292521265896b4399c95ede89d7c8c797a6a57791a849adea489359a158aa12e5dacce862b8333b7ebea7d344d1a3c53198864b73a9dedde7b663abb1b539e1e8853b1b7edb14a2a17ebaae4dbe63598a2e7e9a2dbdad415bc1d8cb88cbab5a8c82925732cd282e641ea3bd7d2c6e776de9117a26be86deb7c82c89524b122cb9397cd1acd2284e744ea62b9279bae85479ababe315c3ac29c431333395b24e6a1e3c43a2da42d4dce84aadd5b154aea555eaddcbd6e527d228c19388d9b424d94214555a7edbdeebe569d4a56dc51a86bd9963e377bb74752bd5eaa5761ba545e297b62a1bda46ab4aee423ad6c661311783cc18786d4289236563cb4a75ec67d481c14814994464cd1b87396dee63e5ab6e952cc584baa1d4c47cb557ec84dbb63d487c8728118673a166846dd3a4ebc23d6cb9c5827d96b4556e91899db32b517eda815ae271a8911bd745447121dc8d321557bc2a435ebec1bbac35b1a291669451174e6aa2218a4a9c5a6ca31ebc45d84e3a82c121e9ced7d55e9a
392 * which has a spot (far right) where slightly more complex loop
393 * avoidance is required.
396 static int dsf_canonify(int *dsf, int val)
400 while (dsf[val] != val)
412 static void dsf_merge(int *dsf, int v1, int v2)
414 v1 = dsf_canonify(dsf, v1);
415 v2 = dsf_canonify(dsf, v2);
420 unsigned char *marked;
426 static struct todo *todo_new(int maxsize)
428 struct todo *todo = snew(struct todo);
429 todo->marked = snewn(maxsize, unsigned char);
430 memset(todo->marked, 0, maxsize);
431 todo->buflen = maxsize + 1;
432 todo->buffer = snewn(todo->buflen, int);
433 todo->head = todo->tail = 0;
437 static void todo_free(struct todo *todo)
444 static void todo_add(struct todo *todo, int index)
446 if (todo->marked[index])
447 return; /* already on the list */
448 todo->marked[index] = TRUE;
449 todo->buffer[todo->tail++] = index;
450 if (todo->tail == todo->buflen)
454 static int todo_get(struct todo *todo) {
457 if (todo->head == todo->tail)
458 return -1; /* list is empty */
459 ret = todo->buffer[todo->head++];
460 if (todo->head == todo->buflen)
462 todo->marked[ret] = FALSE;
467 static int net_solver(int w, int h, unsigned char *tiles,
468 unsigned char *barriers, int wrapping)
470 unsigned char *tilestate;
471 unsigned char *edgestate;
480 * Set up the solver's data structures.
484 * tilestate stores the possible orientations of each tile.
485 * There are up to four of these, so we'll index the array in
486 * fours. tilestate[(y * w + x) * 4] and its three successive
487 * members give the possible orientations, clearing to 255 from
488 * the end as things are ruled out.
490 * In this loop we also count up the area of the grid (which is
491 * not _necessarily_ equal to w*h, because there might be one
492 * or more blank squares present. This will never happen in a
493 * grid generated _by_ this program, but it's worth keeping the
494 * solver as general as possible.)
496 tilestate = snewn(w * h * 4, unsigned char);
498 for (i = 0; i < w*h; i++) {
499 tilestate[i * 4] = tiles[i] & 0xF;
500 for (j = 1; j < 4; j++) {
501 if (tilestate[i * 4 + j - 1] == 255 ||
502 A(tilestate[i * 4 + j - 1]) == tilestate[i * 4])
503 tilestate[i * 4 + j] = 255;
505 tilestate[i * 4 + j] = A(tilestate[i * 4 + j - 1]);
512 * edgestate stores the known state of each edge. It is 0 for
513 * unknown, 1 for open (connected) and 2 for closed (not
516 * In principle we need only worry about each edge once each,
517 * but in fact it's easier to track each edge twice so that we
518 * can reference it from either side conveniently. Also I'm
519 * going to allocate _five_ bytes per tile, rather than the
520 * obvious four, so that I can index edgestate[(y*w+x) * 5 + d]
521 * where d is 1,2,4,8 and they never overlap.
523 edgestate = snewn((w * h - 1) * 5 + 9, unsigned char);
524 memset(edgestate, 0, (w * h - 1) * 5 + 9);
527 * deadends tracks which edges have dead ends on them. It is
528 * indexed by tile and direction: deadends[(y*w+x) * 5 + d]
529 * tells you whether heading out of tile (x,y) in direction d
530 * can reach a limited amount of the grid. Values are area+1
531 * (no dead end known) or less than that (can reach _at most_
532 * this many other tiles by heading this way out of this tile).
534 deadends = snewn((w * h - 1) * 5 + 9, int);
535 for (i = 0; i < (w * h - 1) * 5 + 9; i++)
536 deadends[i] = area+1;
539 * equivalence tracks which sets of tiles are known to be
540 * connected to one another, so we can avoid creating loops by
541 * linking together tiles which are already linked through
544 * This is a disjoint set forest structure: equivalence[i]
545 * contains the index of another member of the equivalence
546 * class containing i, or contains i itself for precisely one
547 * member in each such class. To find a representative member
548 * of the equivalence class containing i, you keep replacing i
549 * with equivalence[i] until it stops changing; then you go
550 * _back_ along the same path and point everything on it
551 * directly at the representative member so as to speed up
552 * future searches. Then you test equivalence between tiles by
553 * finding the representative of each tile and seeing if
554 * they're the same; and you create new equivalence (merge
555 * classes) by finding the representative of each tile and
556 * setting equivalence[one]=the_other.
558 equivalence = snewn(w * h, int);
559 for (i = 0; i < w*h; i++)
560 equivalence[i] = i; /* initially all distinct */
563 * On a non-wrapping grid, we instantly know that all the edges
564 * round the edge are closed.
567 for (i = 0; i < w; i++) {
568 edgestate[i * 5 + 2] = edgestate[((h-1) * w + i) * 5 + 8] = 2;
570 for (i = 0; i < h; i++) {
571 edgestate[(i * w + w-1) * 5 + 1] = edgestate[(i * w) * 5 + 4] = 2;
576 * If we have barriers available, we can mark those edges as
580 for (y = 0; y < h; y++) for (x = 0; x < w; x++) {
582 for (d = 1; d <= 8; d += d) {
583 if (barriers[y*w+x] & d) {
586 * In principle the barrier list should already
587 * contain each barrier from each side, but
588 * let's not take chances with our internal
591 OFFSETWH(x2, y2, x, y, d, w, h);
592 edgestate[(y*w+x) * 5 + d] = 2;
593 edgestate[(y2*w+x2) * 5 + F(d)] = 2;
600 * Since most deductions made by this solver are local (the
601 * exception is loop avoidance, where joining two tiles
602 * together on one side of the grid can theoretically permit a
603 * fresh deduction on the other), we can address the scaling
604 * problem inherent in iterating repeatedly over the entire
605 * grid by instead working with a to-do list.
607 todo = todo_new(w * h);
610 * Main deductive loop.
612 done_something = TRUE; /* prevent instant termination! */
617 * Take a tile index off the todo list and process it.
619 index = todo_get(todo);
622 * If we have run out of immediate things to do, we
623 * have no choice but to scan the whole grid for
624 * longer-range things we've missed. Hence, I now add
625 * every square on the grid back on to the to-do list.
626 * I also set `done_something' to FALSE at this point;
627 * if we later come back here and find it still FALSE,
628 * we will know we've scanned the entire grid without
629 * finding anything new to do, and we can terminate.
633 for (i = 0; i < w*h; i++)
635 done_something = FALSE;
637 index = todo_get(todo);
643 int d, ourclass = dsf_canonify(equivalence, y*w+x);
646 deadendmax[1] = deadendmax[2] = deadendmax[4] = deadendmax[8] = 0;
648 for (i = j = 0; i < 4 && tilestate[(y*w+x) * 4 + i] != 255; i++) {
650 int nnondeadends, nondeadends[4], deadendtotal;
651 int nequiv, equiv[5];
652 int val = tilestate[(y*w+x) * 4 + i];
655 nnondeadends = deadendtotal = 0;
658 for (d = 1; d <= 8; d += d) {
660 * Immediately rule out this orientation if it
661 * conflicts with any known edge.
663 if ((edgestate[(y*w+x) * 5 + d] == 1 && !(val & d)) ||
664 (edgestate[(y*w+x) * 5 + d] == 2 && (val & d)))
669 * Count up the dead-end statistics.
671 if (deadends[(y*w+x) * 5 + d] <= area) {
672 deadendtotal += deadends[(y*w+x) * 5 + d];
674 nondeadends[nnondeadends++] = d;
678 * Ensure we aren't linking to any tiles,
679 * through edges not already known to be
680 * open, which create a loop.
682 if (edgestate[(y*w+x) * 5 + d] == 0) {
685 OFFSETWH(x2, y2, x, y, d, w, h);
686 c = dsf_canonify(equivalence, y2*w+x2);
687 for (k = 0; k < nequiv; k++)
698 if (nnondeadends == 0) {
700 * If this orientation links together dead-ends
701 * with a total area of less than the entire
702 * grid, it is invalid.
704 * (We add 1 to deadendtotal because of the
705 * tile itself, of course; one tile linking
706 * dead ends of size 2 and 3 forms a subnetwork
707 * with a total area of 6, not 5.)
709 if (deadendtotal > 0 && deadendtotal+1 < area)
711 } else if (nnondeadends == 1) {
713 * If this orientation links together one or
714 * more dead-ends with precisely one
715 * non-dead-end, then we may have to mark that
716 * non-dead-end as a dead end going the other
717 * way. However, it depends on whether all
718 * other orientations share the same property.
721 if (deadendmax[nondeadends[0]] < deadendtotal)
722 deadendmax[nondeadends[0]] = deadendtotal;
725 * If this orientation links together two or
726 * more non-dead-ends, then we can rule out the
727 * possibility of putting in new dead-end
728 * markings in those directions.
731 for (k = 0; k < nnondeadends; k++)
732 deadendmax[nondeadends[k]] = area+1;
736 tilestate[(y*w+x) * 4 + j++] = val;
737 #ifdef SOLVER_DIAGNOSTICS
739 printf("ruling out orientation %x at %d,%d\n", val, x, y);
743 assert(j > 0); /* we can't lose _all_ possibilities! */
746 done_something = TRUE;
749 * We have ruled out at least one tile orientation.
750 * Make sure the rest are blanked.
753 tilestate[(y*w+x) * 4 + j++] = 255;
757 * Now go through the tile orientations again and see
758 * if we've deduced anything new about any edges.
764 for (i = 0; i < 4 && tilestate[(y*w+x) * 4 + i] != 255; i++) {
765 a &= tilestate[(y*w+x) * 4 + i];
766 o |= tilestate[(y*w+x) * 4 + i];
768 for (d = 1; d <= 8; d += d)
769 if (edgestate[(y*w+x) * 5 + d] == 0) {
771 OFFSETWH(x2, y2, x, y, d, w, h);
774 /* This edge is open in all orientations. */
775 #ifdef SOLVER_DIAGNOSTICS
776 printf("marking edge %d,%d:%d open\n", x, y, d);
778 edgestate[(y*w+x) * 5 + d] = 1;
779 edgestate[(y2*w+x2) * 5 + d2] = 1;
780 dsf_merge(equivalence, y*w+x, y2*w+x2);
781 done_something = TRUE;
782 todo_add(todo, y2*w+x2);
783 } else if (!(o & d)) {
784 /* This edge is closed in all orientations. */
785 #ifdef SOLVER_DIAGNOSTICS
786 printf("marking edge %d,%d:%d closed\n", x, y, d);
788 edgestate[(y*w+x) * 5 + d] = 2;
789 edgestate[(y2*w+x2) * 5 + d2] = 2;
790 done_something = TRUE;
791 todo_add(todo, y2*w+x2);
798 * Now check the dead-end markers and see if any of
799 * them has lowered from the real ones.
801 for (d = 1; d <= 8; d += d) {
803 OFFSETWH(x2, y2, x, y, d, w, h);
805 if (deadendmax[d] > 0 &&
806 deadends[(y2*w+x2) * 5 + d2] > deadendmax[d]) {
807 #ifdef SOLVER_DIAGNOSTICS
808 printf("setting dead end value %d,%d:%d to %d\n",
809 x2, y2, d2, deadendmax[d]);
811 deadends[(y2*w+x2) * 5 + d2] = deadendmax[d];
812 done_something = TRUE;
813 todo_add(todo, y2*w+x2);
821 * Mark all completely determined tiles as locked.
824 for (i = 0; i < w*h; i++) {
825 if (tilestate[i * 4 + 1] == 255) {
826 assert(tilestate[i * 4 + 0] != 255);
827 tiles[i] = tilestate[i * 4] | LOCKED;
835 * Free up working space.
846 /* ----------------------------------------------------------------------
847 * Randomly select a new game description.
851 * Function to randomly perturb an ambiguous section in a grid, to
852 * attempt to ensure unique solvability.
854 static void perturb(int w, int h, unsigned char *tiles, int wrapping,
855 random_state *rs, int startx, int starty, int startd)
857 struct xyd *perimeter, *perim2, *loop[2], looppos[2];
858 int nperim, perimsize, nloop[2], loopsize[2];
862 * We know that the tile at (startx,starty) is part of an
863 * ambiguous section, and we also know that its neighbour in
864 * direction startd is fully specified. We begin by tracing all
865 * the way round the ambiguous area.
867 nperim = perimsize = 0;
872 #ifdef PERTURB_DIAGNOSTICS
873 printf("perturb %d,%d:%d\n", x, y, d);
878 if (nperim >= perimsize) {
879 perimsize = perimsize * 3 / 2 + 32;
880 perimeter = sresize(perimeter, perimsize, struct xyd);
882 perimeter[nperim].x = x;
883 perimeter[nperim].y = y;
884 perimeter[nperim].direction = d;
886 #ifdef PERTURB_DIAGNOSTICS
887 printf("perimeter: %d,%d:%d\n", x, y, d);
891 * First, see if we can simply turn left from where we are
892 * and find another locked square.
895 OFFSETWH(x2, y2, x, y, d2, w, h);
896 if ((!wrapping && (abs(x2-x) > 1 || abs(y2-y) > 1)) ||
897 (tiles[y2*w+x2] & LOCKED)) {
901 * Failing that, step left into the new square and look
906 OFFSETWH(x2, y2, x, y, d, w, h);
907 if ((wrapping || (abs(x2-x) <= 1 && abs(y2-y) <= 1)) &&
908 !(tiles[y2*w+x2] & LOCKED)) {
910 * And failing _that_, we're going to have to step
911 * forward into _that_ square and look right at the
912 * same locked square as we started with.
920 } while (x != startx || y != starty || d != startd);
923 * Our technique for perturbing this ambiguous area is to
924 * search round its edge for a join we can make: that is, an
925 * edge on the perimeter which is (a) not currently connected,
926 * and (b) connecting it would not yield a full cross on either
927 * side. Then we make that join, search round the network to
928 * find the loop thus constructed, and sever the loop at a
929 * randomly selected other point.
931 perim2 = snewn(nperim, struct xyd);
932 memcpy(perim2, perimeter, nperim * sizeof(struct xyd));
933 /* Shuffle the perimeter, so as to search it without directional bias. */
934 for (i = nperim; --i ;) {
935 int j = random_upto(rs, i+1);
939 perim2[j] = perim2[i];
942 for (i = 0; i < nperim; i++) {
947 d = perim2[i].direction;
949 OFFSETWH(x2, y2, x, y, d, w, h);
950 if (!wrapping && (abs(x2-x) > 1 || abs(y2-y) > 1))
951 continue; /* can't link across non-wrapping border */
952 if (tiles[y*w+x] & d)
953 continue; /* already linked in this direction! */
954 if (((tiles[y*w+x] | d) & 15) == 15)
955 continue; /* can't turn this tile into a cross */
956 if (((tiles[y2*w+x2] | F(d)) & 15) == 15)
957 continue; /* can't turn other tile into a cross */
960 * We've found the point at which we're going to make a new
963 #ifdef PERTURB_DIAGNOSTICS
964 printf("linking %d,%d:%d\n", x, y, d);
967 tiles[y2*w+x2] |= F(d);
973 return; /* nothing we can do! */
976 * Now we've constructed a new link, we need to find the entire
977 * loop of which it is a part.
979 * In principle, this involves doing a complete search round
980 * the network. However, I anticipate that in the vast majority
981 * of cases the loop will be quite small, so what I'm going to
982 * do is make _two_ searches round the network in parallel, one
983 * keeping its metaphorical hand on the left-hand wall while
984 * the other keeps its hand on the right. As soon as one of
985 * them gets back to its starting point, I abandon the other.
987 for (i = 0; i < 2; i++) {
988 loopsize[i] = nloop[i] = 0;
992 looppos[i].direction = d;
995 for (i = 0; i < 2; i++) {
1000 d = looppos[i].direction;
1002 OFFSETWH(x2, y2, x, y, d, w, h);
1005 * Add this path segment to the loop, unless it exactly
1006 * reverses the previous one on the loop in which case
1007 * we take it away again.
1009 #ifdef PERTURB_DIAGNOSTICS
1010 printf("looppos[%d] = %d,%d:%d\n", i, x, y, d);
1013 loop[i][nloop[i]-1].x == x2 &&
1014 loop[i][nloop[i]-1].y == y2 &&
1015 loop[i][nloop[i]-1].direction == F(d)) {
1016 #ifdef PERTURB_DIAGNOSTICS
1017 printf("removing path segment %d,%d:%d from loop[%d]\n",
1022 if (nloop[i] >= loopsize[i]) {
1023 loopsize[i] = loopsize[i] * 3 / 2 + 32;
1024 loop[i] = sresize(loop[i], loopsize[i], struct xyd);
1026 #ifdef PERTURB_DIAGNOSTICS
1027 printf("adding path segment %d,%d:%d to loop[%d]\n",
1030 loop[i][nloop[i]++] = looppos[i];
1033 #ifdef PERTURB_DIAGNOSTICS
1034 printf("tile at new location is %x\n", tiles[y2*w+x2] & 0xF);
1037 for (j = 0; j < 4; j++) {
1042 #ifdef PERTURB_DIAGNOSTICS
1043 printf("trying dir %d\n", d);
1045 if (tiles[y2*w+x2] & d) {
1048 looppos[i].direction = d;
1054 assert(nloop[i] > 0);
1056 if (looppos[i].x == loop[i][0].x &&
1057 looppos[i].y == loop[i][0].y &&
1058 looppos[i].direction == loop[i][0].direction) {
1059 #ifdef PERTURB_DIAGNOSTICS
1060 printf("loop %d finished tracking\n", i);
1064 * Having found our loop, we now sever it at a
1065 * randomly chosen point - absolutely any will do -
1066 * which is not the one we joined it at to begin
1067 * with. Conveniently, the one we joined it at is
1068 * loop[i][0], so we just avoid that one.
1070 j = random_upto(rs, nloop[i]-1) + 1;
1073 d = loop[i][j].direction;
1074 OFFSETWH(x2, y2, x, y, d, w, h);
1076 tiles[y2*w+x2] &= ~F(d);
1088 * Finally, we must mark the entire disputed section as locked,
1089 * to prevent the perturb function being called on it multiple
1092 * To do this, we _sort_ the perimeter of the area. The
1093 * existing xyd_cmp function will arrange things into columns
1094 * for us, in such a way that each column has the edges in
1095 * vertical order. Then we can work down each column and fill
1096 * in all the squares between an up edge and a down edge.
1098 qsort(perimeter, nperim, sizeof(struct xyd), xyd_cmp);
1100 for (i = 0; i <= nperim; i++) {
1101 if (i == nperim || perimeter[i].x > x) {
1103 * Fill in everything from the last Up edge to the
1104 * bottom of the grid, if necessary.
1108 #ifdef PERTURB_DIAGNOSTICS
1109 printf("resolved: locking tile %d,%d\n", x, y);
1111 tiles[y * w + x] |= LOCKED;
1124 if (perimeter[i].direction == U) {
1127 } else if (perimeter[i].direction == D) {
1129 * Fill in everything from the last Up edge to here.
1131 assert(x == perimeter[i].x && y <= perimeter[i].y);
1132 while (y <= perimeter[i].y) {
1133 #ifdef PERTURB_DIAGNOSTICS
1134 printf("resolved: locking tile %d,%d\n", x, y);
1136 tiles[y * w + x] |= LOCKED;
1146 static char *new_game_desc(game_params *params, random_state *rs,
1147 game_aux_info **aux)
1149 tree234 *possibilities, *barriertree;
1150 int w, h, x, y, cx, cy, nbarriers;
1151 unsigned char *tiles, *barriers;
1160 tiles = snewn(w * h, unsigned char);
1161 barriers = snewn(w * h, unsigned char);
1165 memset(tiles, 0, w * h);
1166 memset(barriers, 0, w * h);
1169 * Construct the unshuffled grid.
1171 * To do this, we simply start at the centre point, repeatedly
1172 * choose a random possibility out of the available ways to
1173 * extend a used square into an unused one, and do it. After
1174 * extending the third line out of a square, we remove the
1175 * fourth from the possibilities list to avoid any full-cross
1176 * squares (which would make the game too easy because they
1177 * only have one orientation).
1179 * The slightly worrying thing is the avoidance of full-cross
1180 * squares. Can this cause our unsophisticated construction
1181 * algorithm to paint itself into a corner, by getting into a
1182 * situation where there are some unreached squares and the
1183 * only way to reach any of them is to extend a T-piece into a
1186 * Answer: no it can't, and here's a proof.
1188 * Any contiguous group of such unreachable squares must be
1189 * surrounded on _all_ sides by T-pieces pointing away from the
1190 * group. (If not, then there is a square which can be extended
1191 * into one of the `unreachable' ones, and so it wasn't
1192 * unreachable after all.) In particular, this implies that
1193 * each contiguous group of unreachable squares must be
1194 * rectangular in shape (any deviation from that yields a
1195 * non-T-piece next to an `unreachable' square).
1197 * So we have a rectangle of unreachable squares, with T-pieces
1198 * forming a solid border around the rectangle. The corners of
1199 * that border must be connected (since every tile connects all
1200 * the lines arriving in it), and therefore the border must
1201 * form a closed loop around the rectangle.
1203 * But this can't have happened in the first place, since we
1204 * _know_ we've avoided creating closed loops! Hence, no such
1205 * situation can ever arise, and the naive grid construction
1206 * algorithm will guaranteeably result in a complete grid
1207 * containing no unreached squares, no full crosses _and_ no
1210 possibilities = newtree234(xyd_cmp_nc);
1213 add234(possibilities, new_xyd(cx, cy, R));
1215 add234(possibilities, new_xyd(cx, cy, U));
1217 add234(possibilities, new_xyd(cx, cy, L));
1219 add234(possibilities, new_xyd(cx, cy, D));
1221 while (count234(possibilities) > 0) {
1224 int x1, y1, d1, x2, y2, d2, d;
1227 * Extract a randomly chosen possibility from the list.
1229 i = random_upto(rs, count234(possibilities));
1230 xyd = delpos234(possibilities, i);
1233 d1 = xyd->direction;
1236 OFFSET(x2, y2, x1, y1, d1, params);
1239 printf("picked (%d,%d,%c) <-> (%d,%d,%c)\n",
1240 x1, y1, "0RU3L567D9abcdef"[d1], x2, y2, "0RU3L567D9abcdef"[d2]);
1244 * Make the connection. (We should be moving to an as yet
1247 index(params, tiles, x1, y1) |= d1;
1248 assert(index(params, tiles, x2, y2) == 0);
1249 index(params, tiles, x2, y2) |= d2;
1252 * If we have created a T-piece, remove its last
1255 if (COUNT(index(params, tiles, x1, y1)) == 3) {
1256 struct xyd xyd1, *xydp;
1260 xyd1.direction = 0x0F ^ index(params, tiles, x1, y1);
1262 xydp = find234(possibilities, &xyd1, NULL);
1266 printf("T-piece; removing (%d,%d,%c)\n",
1267 xydp->x, xydp->y, "0RU3L567D9abcdef"[xydp->direction]);
1269 del234(possibilities, xydp);
1275 * Remove all other possibilities that were pointing at the
1276 * tile we've just moved into.
1278 for (d = 1; d < 0x10; d <<= 1) {
1280 struct xyd xyd1, *xydp;
1282 OFFSET(x3, y3, x2, y2, d, params);
1287 xyd1.direction = d3;
1289 xydp = find234(possibilities, &xyd1, NULL);
1293 printf("Loop avoidance; removing (%d,%d,%c)\n",
1294 xydp->x, xydp->y, "0RU3L567D9abcdef"[xydp->direction]);
1296 del234(possibilities, xydp);
1302 * Add new possibilities to the list for moving _out_ of
1303 * the tile we have just moved into.
1305 for (d = 1; d < 0x10; d <<= 1) {
1309 continue; /* we've got this one already */
1311 if (!params->wrapping) {
1312 if (d == U && y2 == 0)
1314 if (d == D && y2 == h-1)
1316 if (d == L && x2 == 0)
1318 if (d == R && x2 == w-1)
1322 OFFSET(x3, y3, x2, y2, d, params);
1324 if (index(params, tiles, x3, y3))
1325 continue; /* this would create a loop */
1328 printf("New frontier; adding (%d,%d,%c)\n",
1329 x2, y2, "0RU3L567D9abcdef"[d]);
1331 add234(possibilities, new_xyd(x2, y2, d));
1334 /* Having done that, we should have no possibilities remaining. */
1335 assert(count234(possibilities) == 0);
1336 freetree234(possibilities);
1338 if (params->unique) {
1342 * Run the solver to check unique solubility.
1344 while (!net_solver(w, h, tiles, NULL, params->wrapping)) {
1348 * We expect (in most cases) that most of the grid will
1349 * be uniquely specified already, and the remaining
1350 * ambiguous sections will be small and separate. So
1351 * our strategy is to find each individual such
1352 * section, and perform a perturbation on the network
1355 for (y = 0; y < h; y++) for (x = 0; x < w; x++) {
1356 if (x+1 < w && ((tiles[y*w+x] ^ tiles[y*w+x+1]) & LOCKED)) {
1358 if (tiles[y*w+x] & LOCKED)
1359 perturb(w, h, tiles, params->wrapping, rs, x+1, y, L);
1361 perturb(w, h, tiles, params->wrapping, rs, x, y, R);
1363 if (y+1 < h && ((tiles[y*w+x] ^ tiles[(y+1)*w+x]) & LOCKED)) {
1365 if (tiles[y*w+x] & LOCKED)
1366 perturb(w, h, tiles, params->wrapping, rs, x, y+1, U);
1368 perturb(w, h, tiles, params->wrapping, rs, x, y, D);
1373 * Now n counts the number of ambiguous sections we
1374 * have fiddled with. If we haven't managed to decrease
1375 * it from the last time we ran the solver, give up and
1376 * regenerate the entire grid.
1378 if (prevn != -1 && prevn <= n)
1379 goto begin_generation; /* (sorry) */
1385 * The solver will have left a lot of LOCKED bits lying
1386 * around in the tiles array. Remove them.
1388 for (x = 0; x < w*h; x++)
1389 tiles[x] &= ~LOCKED;
1393 * Now compute a list of the possible barrier locations.
1395 barriertree = newtree234(xyd_cmp_nc);
1396 for (y = 0; y < h; y++) {
1397 for (x = 0; x < w; x++) {
1399 if (!(index(params, tiles, x, y) & R) &&
1400 (params->wrapping || x < w-1))
1401 add234(barriertree, new_xyd(x, y, R));
1402 if (!(index(params, tiles, x, y) & D) &&
1403 (params->wrapping || y < h-1))
1404 add234(barriertree, new_xyd(x, y, D));
1409 * Save the unshuffled grid in an aux_info.
1412 game_aux_info *solution;
1414 solution = snew(game_aux_info);
1415 solution->width = w;
1416 solution->height = h;
1417 solution->tiles = snewn(w * h, unsigned char);
1418 memcpy(solution->tiles, tiles, w * h);
1424 * Now shuffle the grid.
1426 for (y = 0; y < h; y++) {
1427 for (x = 0; x < w; x++) {
1428 int orig = index(params, tiles, x, y);
1429 int rot = random_upto(rs, 4);
1430 index(params, tiles, x, y) = ROT(orig, rot);
1435 * And now choose barrier locations. (We carefully do this
1436 * _after_ shuffling, so that changing the barrier rate in the
1437 * params while keeping the random seed the same will give the
1438 * same shuffled grid and _only_ change the barrier locations.
1439 * Also the way we choose barrier locations, by repeatedly
1440 * choosing one possibility from the list until we have enough,
1441 * is designed to ensure that raising the barrier rate while
1442 * keeping the seed the same will provide a superset of the
1443 * previous barrier set - i.e. if you ask for 10 barriers, and
1444 * then decide that's still too hard and ask for 20, you'll get
1445 * the original 10 plus 10 more, rather than getting 20 new
1446 * ones and the chance of remembering your first 10.)
1448 nbarriers = (int)(params->barrier_probability * count234(barriertree));
1449 assert(nbarriers >= 0 && nbarriers <= count234(barriertree));
1451 while (nbarriers > 0) {
1454 int x1, y1, d1, x2, y2, d2;
1457 * Extract a randomly chosen barrier from the list.
1459 i = random_upto(rs, count234(barriertree));
1460 xyd = delpos234(barriertree, i);
1462 assert(xyd != NULL);
1466 d1 = xyd->direction;
1469 OFFSET(x2, y2, x1, y1, d1, params);
1472 index(params, barriers, x1, y1) |= d1;
1473 index(params, barriers, x2, y2) |= d2;
1479 * Clean up the rest of the barrier list.
1484 while ( (xyd = delpos234(barriertree, 0)) != NULL)
1487 freetree234(barriertree);
1491 * Finally, encode the grid into a string game description.
1493 * My syntax is extremely simple: each square is encoded as a
1494 * hex digit in which bit 0 means a connection on the right,
1495 * bit 1 means up, bit 2 left and bit 3 down. (i.e. the same
1496 * encoding as used internally). Each digit is followed by
1497 * optional barrier indicators: `v' means a vertical barrier to
1498 * the right of it, and `h' means a horizontal barrier below
1501 desc = snewn(w * h * 3 + 1, char);
1503 for (y = 0; y < h; y++) {
1504 for (x = 0; x < w; x++) {
1505 *p++ = "0123456789abcdef"[index(params, tiles, x, y)];
1506 if ((params->wrapping || x < w-1) &&
1507 (index(params, barriers, x, y) & R))
1509 if ((params->wrapping || y < h-1) &&
1510 (index(params, barriers, x, y) & D))
1514 assert(p - desc <= w*h*3);
1523 static void game_free_aux_info(game_aux_info *aux)
1529 static char *validate_desc(game_params *params, char *desc)
1531 int w = params->width, h = params->height;
1534 for (i = 0; i < w*h; i++) {
1535 if (*desc >= '0' && *desc <= '9')
1537 else if (*desc >= 'a' && *desc <= 'f')
1539 else if (*desc >= 'A' && *desc <= 'F')
1542 return "Game description shorter than expected";
1544 return "Game description contained unexpected character";
1546 while (*desc == 'h' || *desc == 'v')
1550 return "Game description longer than expected";
1555 /* ----------------------------------------------------------------------
1556 * Construct an initial game state, given a description and parameters.
1559 static game_state *new_game(game_params *params, char *desc)
1564 assert(params->width > 0 && params->height > 0);
1565 assert(params->width > 1 || params->height > 1);
1568 * Create a blank game state.
1570 state = snew(game_state);
1571 w = state->width = params->width;
1572 h = state->height = params->height;
1573 state->cx = state->width / 2;
1574 state->cy = state->height / 2;
1575 state->wrapping = params->wrapping;
1576 state->last_rotate_dir = state->last_rotate_x = state->last_rotate_y = 0;
1577 state->completed = state->used_solve = state->just_used_solve = FALSE;
1578 state->tiles = snewn(state->width * state->height, unsigned char);
1579 memset(state->tiles, 0, state->width * state->height);
1580 state->barriers = snewn(state->width * state->height, unsigned char);
1581 memset(state->barriers, 0, state->width * state->height);
1584 * Parse the game description into the grid.
1586 for (y = 0; y < h; y++) {
1587 for (x = 0; x < w; x++) {
1588 if (*desc >= '0' && *desc <= '9')
1589 tile(state, x, y) = *desc - '0';
1590 else if (*desc >= 'a' && *desc <= 'f')
1591 tile(state, x, y) = *desc - 'a' + 10;
1592 else if (*desc >= 'A' && *desc <= 'F')
1593 tile(state, x, y) = *desc - 'A' + 10;
1596 while (*desc == 'h' || *desc == 'v') {
1603 OFFSET(x2, y2, x, y, d1, state);
1606 barrier(state, x, y) |= d1;
1607 barrier(state, x2, y2) |= d2;
1615 * Set up border barriers if this is a non-wrapping game.
1617 if (!state->wrapping) {
1618 for (x = 0; x < state->width; x++) {
1619 barrier(state, x, 0) |= U;
1620 barrier(state, x, state->height-1) |= D;
1622 for (y = 0; y < state->height; y++) {
1623 barrier(state, 0, y) |= L;
1624 barrier(state, state->width-1, y) |= R;
1629 * Set up the barrier corner flags, for drawing barriers
1630 * prettily when they meet.
1632 for (y = 0; y < state->height; y++) {
1633 for (x = 0; x < state->width; x++) {
1636 for (dir = 1; dir < 0x10; dir <<= 1) {
1638 int x1, y1, x2, y2, x3, y3;
1641 if (!(barrier(state, x, y) & dir))
1644 if (barrier(state, x, y) & dir2)
1647 x1 = x + X(dir), y1 = y + Y(dir);
1648 if (x1 >= 0 && x1 < state->width &&
1649 y1 >= 0 && y1 < state->height &&
1650 (barrier(state, x1, y1) & dir2))
1653 x2 = x + X(dir2), y2 = y + Y(dir2);
1654 if (x2 >= 0 && x2 < state->width &&
1655 y2 >= 0 && y2 < state->height &&
1656 (barrier(state, x2, y2) & dir))
1660 barrier(state, x, y) |= (dir << 4);
1661 if (x1 >= 0 && x1 < state->width &&
1662 y1 >= 0 && y1 < state->height)
1663 barrier(state, x1, y1) |= (A(dir) << 4);
1664 if (x2 >= 0 && x2 < state->width &&
1665 y2 >= 0 && y2 < state->height)
1666 barrier(state, x2, y2) |= (C(dir) << 4);
1667 x3 = x + X(dir) + X(dir2), y3 = y + Y(dir) + Y(dir2);
1668 if (x3 >= 0 && x3 < state->width &&
1669 y3 >= 0 && y3 < state->height)
1670 barrier(state, x3, y3) |= (F(dir) << 4);
1679 static game_state *dup_game(game_state *state)
1683 ret = snew(game_state);
1684 ret->width = state->width;
1685 ret->height = state->height;
1686 ret->cx = state->cx;
1687 ret->cy = state->cy;
1688 ret->wrapping = state->wrapping;
1689 ret->completed = state->completed;
1690 ret->used_solve = state->used_solve;
1691 ret->just_used_solve = state->just_used_solve;
1692 ret->last_rotate_dir = state->last_rotate_dir;
1693 ret->last_rotate_x = state->last_rotate_x;
1694 ret->last_rotate_y = state->last_rotate_y;
1695 ret->tiles = snewn(state->width * state->height, unsigned char);
1696 memcpy(ret->tiles, state->tiles, state->width * state->height);
1697 ret->barriers = snewn(state->width * state->height, unsigned char);
1698 memcpy(ret->barriers, state->barriers, state->width * state->height);
1703 static void free_game(game_state *state)
1705 sfree(state->tiles);
1706 sfree(state->barriers);
1710 static game_state *solve_game(game_state *state, game_aux_info *aux,
1717 * Run the internal solver on the provided grid. This might
1718 * not yield a complete solution.
1720 ret = dup_game(state);
1721 net_solver(ret->width, ret->height, ret->tiles,
1722 ret->barriers, ret->wrapping);
1724 assert(aux->width == state->width);
1725 assert(aux->height == state->height);
1726 ret = dup_game(state);
1727 memcpy(ret->tiles, aux->tiles, ret->width * ret->height);
1728 ret->used_solve = ret->just_used_solve = TRUE;
1729 ret->completed = TRUE;
1735 static char *game_text_format(game_state *state)
1740 /* ----------------------------------------------------------------------
1745 * Compute which squares are reachable from the centre square, as a
1746 * quick visual aid to determining how close the game is to
1747 * completion. This is also a simple way to tell if the game _is_
1748 * completed - just call this function and see whether every square
1751 static unsigned char *compute_active(game_state *state)
1753 unsigned char *active;
1757 active = snewn(state->width * state->height, unsigned char);
1758 memset(active, 0, state->width * state->height);
1761 * We only store (x,y) pairs in todo, but it's easier to reuse
1762 * xyd_cmp and just store direction 0 every time.
1764 todo = newtree234(xyd_cmp_nc);
1765 index(state, active, state->cx, state->cy) = ACTIVE;
1766 add234(todo, new_xyd(state->cx, state->cy, 0));
1768 while ( (xyd = delpos234(todo, 0)) != NULL) {
1769 int x1, y1, d1, x2, y2, d2;
1775 for (d1 = 1; d1 < 0x10; d1 <<= 1) {
1776 OFFSET(x2, y2, x1, y1, d1, state);
1780 * If the next tile in this direction is connected to
1781 * us, and there isn't a barrier in the way, and it
1782 * isn't already marked active, then mark it active and
1783 * add it to the to-examine list.
1785 if ((tile(state, x1, y1) & d1) &&
1786 (tile(state, x2, y2) & d2) &&
1787 !(barrier(state, x1, y1) & d1) &&
1788 !index(state, active, x2, y2)) {
1789 index(state, active, x2, y2) = ACTIVE;
1790 add234(todo, new_xyd(x2, y2, 0));
1794 /* Now we expect the todo list to have shrunk to zero size. */
1795 assert(count234(todo) == 0);
1804 random_state *rs; /* used for jumbling */
1807 static game_ui *new_ui(game_state *state)
1811 game_ui *ui = snew(game_ui);
1812 ui->cur_x = state->width / 2;
1813 ui->cur_y = state->height / 2;
1814 ui->cur_visible = FALSE;
1815 get_random_seed(&seed, &seedsize);
1816 ui->rs = random_init(seed, seedsize);
1822 static void free_ui(game_ui *ui)
1824 random_free(ui->rs);
1828 /* ----------------------------------------------------------------------
1831 static game_state *make_move(game_state *state, game_ui *ui,
1832 int x, int y, int button)
1834 game_state *ret, *nullret;
1839 if (button == LEFT_BUTTON ||
1840 button == MIDDLE_BUTTON ||
1841 button == RIGHT_BUTTON) {
1843 if (ui->cur_visible) {
1844 ui->cur_visible = FALSE;
1849 * The button must have been clicked on a valid tile.
1851 x -= WINDOW_OFFSET + TILE_BORDER;
1852 y -= WINDOW_OFFSET + TILE_BORDER;
1857 if (tx >= state->width || ty >= state->height)
1859 if (x % TILE_SIZE >= TILE_SIZE - TILE_BORDER ||
1860 y % TILE_SIZE >= TILE_SIZE - TILE_BORDER)
1862 } else if (button == CURSOR_UP || button == CURSOR_DOWN ||
1863 button == CURSOR_RIGHT || button == CURSOR_LEFT) {
1864 if (button == CURSOR_UP && ui->cur_y > 0)
1866 else if (button == CURSOR_DOWN && ui->cur_y < state->height-1)
1868 else if (button == CURSOR_LEFT && ui->cur_x > 0)
1870 else if (button == CURSOR_RIGHT && ui->cur_x < state->width-1)
1873 return nullret; /* no cursor movement */
1874 ui->cur_visible = TRUE;
1875 return state; /* UI activity has occurred */
1876 } else if (button == 'a' || button == 's' || button == 'd' ||
1877 button == 'A' || button == 'S' || button == 'D') {
1880 if (button == 'a' || button == 'A')
1881 button = LEFT_BUTTON;
1882 else if (button == 's' || button == 'S')
1883 button = MIDDLE_BUTTON;
1884 else if (button == 'd' || button == 'D')
1885 button = RIGHT_BUTTON;
1886 ui->cur_visible = TRUE;
1887 } else if (button == 'j' || button == 'J') {
1888 /* XXX should we have some mouse control for this? */
1889 button = 'J'; /* canonify */
1890 tx = ty = -1; /* shut gcc up :( */
1895 * The middle button locks or unlocks a tile. (A locked tile
1896 * cannot be turned, and is visually marked as being locked.
1897 * This is a convenience for the player, so that once they are
1898 * sure which way round a tile goes, they can lock it and thus
1899 * avoid forgetting later on that they'd already done that one;
1900 * and the locking also prevents them turning the tile by
1901 * accident. If they change their mind, another middle click
1904 if (button == MIDDLE_BUTTON) {
1906 ret = dup_game(state);
1907 ret->just_used_solve = FALSE;
1908 tile(ret, tx, ty) ^= LOCKED;
1909 ret->last_rotate_dir = ret->last_rotate_x = ret->last_rotate_y = 0;
1912 } else if (button == LEFT_BUTTON || button == RIGHT_BUTTON) {
1915 * The left and right buttons have no effect if clicked on a
1918 if (tile(state, tx, ty) & LOCKED)
1922 * Otherwise, turn the tile one way or the other. Left button
1923 * turns anticlockwise; right button turns clockwise.
1925 ret = dup_game(state);
1926 ret->just_used_solve = FALSE;
1927 orig = tile(ret, tx, ty);
1928 if (button == LEFT_BUTTON) {
1929 tile(ret, tx, ty) = A(orig);
1930 ret->last_rotate_dir = +1;
1932 tile(ret, tx, ty) = C(orig);
1933 ret->last_rotate_dir = -1;
1935 ret->last_rotate_x = tx;
1936 ret->last_rotate_y = ty;
1938 } else if (button == 'J') {
1941 * Jumble all unlocked tiles to random orientations.
1944 ret = dup_game(state);
1945 ret->just_used_solve = FALSE;
1946 for (jy = 0; jy < ret->height; jy++) {
1947 for (jx = 0; jx < ret->width; jx++) {
1948 if (!(tile(ret, jx, jy) & LOCKED)) {
1949 int rot = random_upto(ui->rs, 4);
1950 orig = tile(ret, jx, jy);
1951 tile(ret, jx, jy) = ROT(orig, rot);
1955 ret->last_rotate_dir = 0; /* suppress animation */
1956 ret->last_rotate_x = ret->last_rotate_y = 0;
1961 * Check whether the game has been completed.
1964 unsigned char *active = compute_active(ret);
1966 int complete = TRUE;
1968 for (x1 = 0; x1 < ret->width; x1++)
1969 for (y1 = 0; y1 < ret->height; y1++)
1970 if ((tile(ret, x1, y1) & 0xF) && !index(ret, active, x1, y1)) {
1972 goto break_label; /* break out of two loops at once */
1979 ret->completed = TRUE;
1985 /* ----------------------------------------------------------------------
1986 * Routines for drawing the game position on the screen.
1989 struct game_drawstate {
1992 unsigned char *visible;
1995 static game_drawstate *game_new_drawstate(game_state *state)
1997 game_drawstate *ds = snew(game_drawstate);
1999 ds->started = FALSE;
2000 ds->width = state->width;
2001 ds->height = state->height;
2002 ds->visible = snewn(state->width * state->height, unsigned char);
2003 memset(ds->visible, 0xFF, state->width * state->height);
2008 static void game_free_drawstate(game_drawstate *ds)
2014 static void game_size(game_params *params, int *x, int *y)
2016 *x = WINDOW_OFFSET * 2 + TILE_SIZE * params->width + TILE_BORDER;
2017 *y = WINDOW_OFFSET * 2 + TILE_SIZE * params->height + TILE_BORDER;
2020 static float *game_colours(frontend *fe, game_state *state, int *ncolours)
2024 ret = snewn(NCOLOURS * 3, float);
2025 *ncolours = NCOLOURS;
2028 * Basic background colour is whatever the front end thinks is
2029 * a sensible default.
2031 frontend_default_colour(fe, &ret[COL_BACKGROUND * 3]);
2036 ret[COL_WIRE * 3 + 0] = 0.0F;
2037 ret[COL_WIRE * 3 + 1] = 0.0F;
2038 ret[COL_WIRE * 3 + 2] = 0.0F;
2041 * Powered wires and powered endpoints are cyan.
2043 ret[COL_POWERED * 3 + 0] = 0.0F;
2044 ret[COL_POWERED * 3 + 1] = 1.0F;
2045 ret[COL_POWERED * 3 + 2] = 1.0F;
2050 ret[COL_BARRIER * 3 + 0] = 1.0F;
2051 ret[COL_BARRIER * 3 + 1] = 0.0F;
2052 ret[COL_BARRIER * 3 + 2] = 0.0F;
2055 * Unpowered endpoints are blue.
2057 ret[COL_ENDPOINT * 3 + 0] = 0.0F;
2058 ret[COL_ENDPOINT * 3 + 1] = 0.0F;
2059 ret[COL_ENDPOINT * 3 + 2] = 1.0F;
2062 * Tile borders are a darker grey than the background.
2064 ret[COL_BORDER * 3 + 0] = 0.5F * ret[COL_BACKGROUND * 3 + 0];
2065 ret[COL_BORDER * 3 + 1] = 0.5F * ret[COL_BACKGROUND * 3 + 1];
2066 ret[COL_BORDER * 3 + 2] = 0.5F * ret[COL_BACKGROUND * 3 + 2];
2069 * Locked tiles are a grey in between those two.
2071 ret[COL_LOCKED * 3 + 0] = 0.75F * ret[COL_BACKGROUND * 3 + 0];
2072 ret[COL_LOCKED * 3 + 1] = 0.75F * ret[COL_BACKGROUND * 3 + 1];
2073 ret[COL_LOCKED * 3 + 2] = 0.75F * ret[COL_BACKGROUND * 3 + 2];
2078 static void draw_thick_line(frontend *fe, int x1, int y1, int x2, int y2,
2081 draw_line(fe, x1-1, y1, x2-1, y2, COL_WIRE);
2082 draw_line(fe, x1+1, y1, x2+1, y2, COL_WIRE);
2083 draw_line(fe, x1, y1-1, x2, y2-1, COL_WIRE);
2084 draw_line(fe, x1, y1+1, x2, y2+1, COL_WIRE);
2085 draw_line(fe, x1, y1, x2, y2, colour);
2088 static void draw_rect_coords(frontend *fe, int x1, int y1, int x2, int y2,
2091 int mx = (x1 < x2 ? x1 : x2);
2092 int my = (y1 < y2 ? y1 : y2);
2093 int dx = (x2 + x1 - 2*mx + 1);
2094 int dy = (y2 + y1 - 2*my + 1);
2096 draw_rect(fe, mx, my, dx, dy, colour);
2099 static void draw_barrier_corner(frontend *fe, int x, int y, int dir, int phase)
2101 int bx = WINDOW_OFFSET + TILE_SIZE * x;
2102 int by = WINDOW_OFFSET + TILE_SIZE * y;
2103 int x1, y1, dx, dy, dir2;
2108 dx = X(dir) + X(dir2);
2109 dy = Y(dir) + Y(dir2);
2110 x1 = (dx > 0 ? TILE_SIZE+TILE_BORDER-1 : 0);
2111 y1 = (dy > 0 ? TILE_SIZE+TILE_BORDER-1 : 0);
2114 draw_rect_coords(fe, bx+x1, by+y1,
2115 bx+x1-TILE_BORDER*dx, by+y1-(TILE_BORDER-1)*dy,
2117 draw_rect_coords(fe, bx+x1, by+y1,
2118 bx+x1-(TILE_BORDER-1)*dx, by+y1-TILE_BORDER*dy,
2121 draw_rect_coords(fe, bx+x1, by+y1,
2122 bx+x1-(TILE_BORDER-1)*dx, by+y1-(TILE_BORDER-1)*dy,
2127 static void draw_barrier(frontend *fe, int x, int y, int dir, int phase)
2129 int bx = WINDOW_OFFSET + TILE_SIZE * x;
2130 int by = WINDOW_OFFSET + TILE_SIZE * y;
2133 x1 = (X(dir) > 0 ? TILE_SIZE : X(dir) == 0 ? TILE_BORDER : 0);
2134 y1 = (Y(dir) > 0 ? TILE_SIZE : Y(dir) == 0 ? TILE_BORDER : 0);
2135 w = (X(dir) ? TILE_BORDER : TILE_SIZE - TILE_BORDER);
2136 h = (Y(dir) ? TILE_BORDER : TILE_SIZE - TILE_BORDER);
2139 draw_rect(fe, bx+x1-X(dir), by+y1-Y(dir), w, h, COL_WIRE);
2141 draw_rect(fe, bx+x1, by+y1, w, h, COL_BARRIER);
2145 static void draw_tile(frontend *fe, game_state *state, int x, int y, int tile,
2146 float angle, int cursor)
2148 int bx = WINDOW_OFFSET + TILE_SIZE * x;
2149 int by = WINDOW_OFFSET + TILE_SIZE * y;
2151 float cx, cy, ex, ey, tx, ty;
2152 int dir, col, phase;
2155 * When we draw a single tile, we must draw everything up to
2156 * and including the borders around the tile. This means that
2157 * if the neighbouring tiles have connections to those borders,
2158 * we must draw those connections on the borders themselves.
2160 * This would be terribly fiddly if we ever had to draw a tile
2161 * while its neighbour was in mid-rotate, because we'd have to
2162 * arrange to _know_ that the neighbour was being rotated and
2163 * hence had an anomalous effect on the redraw of this tile.
2164 * Fortunately, the drawing algorithm avoids ever calling us in
2165 * this circumstance: we're either drawing lots of straight
2166 * tiles at game start or after a move is complete, or we're
2167 * repeatedly drawing only the rotating tile. So no problem.
2171 * So. First blank the tile out completely: draw a big
2172 * rectangle in border colour, and a smaller rectangle in
2173 * background colour to fill it in.
2175 draw_rect(fe, bx, by, TILE_SIZE+TILE_BORDER, TILE_SIZE+TILE_BORDER,
2177 draw_rect(fe, bx+TILE_BORDER, by+TILE_BORDER,
2178 TILE_SIZE-TILE_BORDER, TILE_SIZE-TILE_BORDER,
2179 tile & LOCKED ? COL_LOCKED : COL_BACKGROUND);
2182 * Draw an inset outline rectangle as a cursor, in whichever of
2183 * COL_LOCKED and COL_BACKGROUND we aren't currently drawing
2187 draw_line(fe, bx+TILE_SIZE/8, by+TILE_SIZE/8,
2188 bx+TILE_SIZE/8, by+TILE_SIZE-TILE_SIZE/8,
2189 tile & LOCKED ? COL_BACKGROUND : COL_LOCKED);
2190 draw_line(fe, bx+TILE_SIZE/8, by+TILE_SIZE/8,
2191 bx+TILE_SIZE-TILE_SIZE/8, by+TILE_SIZE/8,
2192 tile & LOCKED ? COL_BACKGROUND : COL_LOCKED);
2193 draw_line(fe, bx+TILE_SIZE-TILE_SIZE/8, by+TILE_SIZE/8,
2194 bx+TILE_SIZE-TILE_SIZE/8, by+TILE_SIZE-TILE_SIZE/8,
2195 tile & LOCKED ? COL_BACKGROUND : COL_LOCKED);
2196 draw_line(fe, bx+TILE_SIZE/8, by+TILE_SIZE-TILE_SIZE/8,
2197 bx+TILE_SIZE-TILE_SIZE/8, by+TILE_SIZE-TILE_SIZE/8,
2198 tile & LOCKED ? COL_BACKGROUND : COL_LOCKED);
2202 * Set up the rotation matrix.
2204 matrix[0] = (float)cos(angle * PI / 180.0);
2205 matrix[1] = (float)-sin(angle * PI / 180.0);
2206 matrix[2] = (float)sin(angle * PI / 180.0);
2207 matrix[3] = (float)cos(angle * PI / 180.0);
2212 cx = cy = TILE_BORDER + (TILE_SIZE-TILE_BORDER) / 2.0F - 0.5F;
2213 col = (tile & ACTIVE ? COL_POWERED : COL_WIRE);
2214 for (dir = 1; dir < 0x10; dir <<= 1) {
2216 ex = (TILE_SIZE - TILE_BORDER - 1.0F) / 2.0F * X(dir);
2217 ey = (TILE_SIZE - TILE_BORDER - 1.0F) / 2.0F * Y(dir);
2218 MATMUL(tx, ty, matrix, ex, ey);
2219 draw_thick_line(fe, bx+(int)cx, by+(int)cy,
2220 bx+(int)(cx+tx), by+(int)(cy+ty),
2224 for (dir = 1; dir < 0x10; dir <<= 1) {
2226 ex = (TILE_SIZE - TILE_BORDER - 1.0F) / 2.0F * X(dir);
2227 ey = (TILE_SIZE - TILE_BORDER - 1.0F) / 2.0F * Y(dir);
2228 MATMUL(tx, ty, matrix, ex, ey);
2229 draw_line(fe, bx+(int)cx, by+(int)cy,
2230 bx+(int)(cx+tx), by+(int)(cy+ty), col);
2235 * Draw the box in the middle. We do this in blue if the tile
2236 * is an unpowered endpoint, in cyan if the tile is a powered
2237 * endpoint, in black if the tile is the centrepiece, and
2238 * otherwise not at all.
2241 if (x == state->cx && y == state->cy)
2243 else if (COUNT(tile) == 1) {
2244 col = (tile & ACTIVE ? COL_POWERED : COL_ENDPOINT);
2249 points[0] = +1; points[1] = +1;
2250 points[2] = +1; points[3] = -1;
2251 points[4] = -1; points[5] = -1;
2252 points[6] = -1; points[7] = +1;
2254 for (i = 0; i < 8; i += 2) {
2255 ex = (TILE_SIZE * 0.24F) * points[i];
2256 ey = (TILE_SIZE * 0.24F) * points[i+1];
2257 MATMUL(tx, ty, matrix, ex, ey);
2258 points[i] = bx+(int)(cx+tx);
2259 points[i+1] = by+(int)(cy+ty);
2262 draw_polygon(fe, points, 4, TRUE, col);
2263 draw_polygon(fe, points, 4, FALSE, COL_WIRE);
2267 * Draw the points on the border if other tiles are connected
2270 for (dir = 1; dir < 0x10; dir <<= 1) {
2271 int dx, dy, px, py, lx, ly, vx, vy, ox, oy;
2279 if (ox < 0 || ox >= state->width || oy < 0 || oy >= state->height)
2282 if (!(tile(state, ox, oy) & F(dir)))
2285 px = bx + (int)(dx>0 ? TILE_SIZE + TILE_BORDER - 1 : dx<0 ? 0 : cx);
2286 py = by + (int)(dy>0 ? TILE_SIZE + TILE_BORDER - 1 : dy<0 ? 0 : cy);
2287 lx = dx * (TILE_BORDER-1);
2288 ly = dy * (TILE_BORDER-1);
2292 if (angle == 0.0 && (tile & dir)) {
2294 * If we are fully connected to the other tile, we must
2295 * draw right across the tile border. (We can use our
2296 * own ACTIVE state to determine what colour to do this
2297 * in: if we are fully connected to the other tile then
2298 * the two ACTIVE states will be the same.)
2300 draw_rect_coords(fe, px-vx, py-vy, px+lx+vx, py+ly+vy, COL_WIRE);
2301 draw_rect_coords(fe, px, py, px+lx, py+ly,
2302 (tile & ACTIVE) ? COL_POWERED : COL_WIRE);
2305 * The other tile extends into our border, but isn't
2306 * actually connected to us. Just draw a single black
2309 draw_rect_coords(fe, px, py, px, py, COL_WIRE);
2314 * Draw barrier corners, and then barriers.
2316 for (phase = 0; phase < 2; phase++) {
2317 for (dir = 1; dir < 0x10; dir <<= 1)
2318 if (barrier(state, x, y) & (dir << 4))
2319 draw_barrier_corner(fe, x, y, dir << 4, phase);
2320 for (dir = 1; dir < 0x10; dir <<= 1)
2321 if (barrier(state, x, y) & dir)
2322 draw_barrier(fe, x, y, dir, phase);
2325 draw_update(fe, bx, by, TILE_SIZE+TILE_BORDER, TILE_SIZE+TILE_BORDER);
2328 static void game_redraw(frontend *fe, game_drawstate *ds, game_state *oldstate,
2329 game_state *state, int dir, game_ui *ui, float t, float ft)
2331 int x, y, tx, ty, frame, last_rotate_dir;
2332 unsigned char *active;
2336 * Clear the screen and draw the exterior barrier lines if this
2337 * is our first call.
2345 WINDOW_OFFSET * 2 + TILE_SIZE * state->width + TILE_BORDER,
2346 WINDOW_OFFSET * 2 + TILE_SIZE * state->height + TILE_BORDER,
2348 draw_update(fe, 0, 0,
2349 WINDOW_OFFSET*2 + TILE_SIZE*state->width + TILE_BORDER,
2350 WINDOW_OFFSET*2 + TILE_SIZE*state->height + TILE_BORDER);
2352 for (phase = 0; phase < 2; phase++) {
2354 for (x = 0; x < ds->width; x++) {
2355 if (barrier(state, x, 0) & UL)
2356 draw_barrier_corner(fe, x, -1, LD, phase);
2357 if (barrier(state, x, 0) & RU)
2358 draw_barrier_corner(fe, x, -1, DR, phase);
2359 if (barrier(state, x, 0) & U)
2360 draw_barrier(fe, x, -1, D, phase);
2361 if (barrier(state, x, ds->height-1) & DR)
2362 draw_barrier_corner(fe, x, ds->height, RU, phase);
2363 if (barrier(state, x, ds->height-1) & LD)
2364 draw_barrier_corner(fe, x, ds->height, UL, phase);
2365 if (barrier(state, x, ds->height-1) & D)
2366 draw_barrier(fe, x, ds->height, U, phase);
2369 for (y = 0; y < ds->height; y++) {
2370 if (barrier(state, 0, y) & UL)
2371 draw_barrier_corner(fe, -1, y, RU, phase);
2372 if (barrier(state, 0, y) & LD)
2373 draw_barrier_corner(fe, -1, y, DR, phase);
2374 if (barrier(state, 0, y) & L)
2375 draw_barrier(fe, -1, y, R, phase);
2376 if (barrier(state, ds->width-1, y) & RU)
2377 draw_barrier_corner(fe, ds->width, y, UL, phase);
2378 if (barrier(state, ds->width-1, y) & DR)
2379 draw_barrier_corner(fe, ds->width, y, LD, phase);
2380 if (barrier(state, ds->width-1, y) & R)
2381 draw_barrier(fe, ds->width, y, L, phase);
2387 last_rotate_dir = dir==-1 ? oldstate->last_rotate_dir :
2388 state->last_rotate_dir;
2389 if (oldstate && (t < ROTATE_TIME) && last_rotate_dir) {
2391 * We're animating a single tile rotation. Find the turning
2394 tx = (dir==-1 ? oldstate->last_rotate_x : state->last_rotate_x);
2395 ty = (dir==-1 ? oldstate->last_rotate_y : state->last_rotate_y);
2396 angle = last_rotate_dir * dir * 90.0F * (t / ROTATE_TIME);
2403 * We're animating a completion flash. Find which frame
2406 frame = (int)(ft / FLASH_FRAME);
2410 * Draw any tile which differs from the way it was last drawn.
2412 active = compute_active(state);
2414 for (x = 0; x < ds->width; x++)
2415 for (y = 0; y < ds->height; y++) {
2416 unsigned char c = tile(state, x, y) | index(state, active, x, y);
2419 * In a completion flash, we adjust the LOCKED bit
2420 * depending on our distance from the centre point and
2424 int xdist, ydist, dist;
2425 xdist = (x < state->cx ? state->cx - x : x - state->cx);
2426 ydist = (y < state->cy ? state->cy - y : y - state->cy);
2427 dist = (xdist > ydist ? xdist : ydist);
2429 if (frame >= dist && frame < dist+4) {
2430 int lock = (frame - dist) & 1;
2431 lock = lock ? LOCKED : 0;
2432 c = (c &~ LOCKED) | lock;
2436 if (index(state, ds->visible, x, y) != c ||
2437 index(state, ds->visible, x, y) == 0xFF ||
2438 (x == tx && y == ty) ||
2439 (ui->cur_visible && x == ui->cur_x && y == ui->cur_y)) {
2440 draw_tile(fe, state, x, y, c,
2441 (x == tx && y == ty ? angle : 0.0F),
2442 (ui->cur_visible && x == ui->cur_x && y == ui->cur_y));
2443 if ((x == tx && y == ty) ||
2444 (ui->cur_visible && x == ui->cur_x && y == ui->cur_y))
2445 index(state, ds->visible, x, y) = 0xFF;
2447 index(state, ds->visible, x, y) = c;
2452 * Update the status bar.
2455 char statusbuf[256];
2458 n = state->width * state->height;
2459 for (i = a = n2 = 0; i < n; i++) {
2462 if (state->tiles[i] & 0xF)
2466 sprintf(statusbuf, "%sActive: %d/%d",
2467 (state->used_solve ? "Auto-solved. " :
2468 state->completed ? "COMPLETED! " : ""), a, n2);
2470 status_bar(fe, statusbuf);
2476 static float game_anim_length(game_state *oldstate,
2477 game_state *newstate, int dir)
2479 int last_rotate_dir;
2482 * Don't animate an auto-solve move.
2484 if ((dir > 0 && newstate->just_used_solve) ||
2485 (dir < 0 && oldstate->just_used_solve))
2489 * Don't animate if last_rotate_dir is zero.
2491 last_rotate_dir = dir==-1 ? oldstate->last_rotate_dir :
2492 newstate->last_rotate_dir;
2493 if (last_rotate_dir)
2499 static float game_flash_length(game_state *oldstate,
2500 game_state *newstate, int dir)
2503 * If the game has just been completed, we display a completion
2506 if (!oldstate->completed && newstate->completed &&
2507 !oldstate->used_solve && !newstate->used_solve) {
2510 if (size < newstate->cx+1)
2511 size = newstate->cx+1;
2512 if (size < newstate->cy+1)
2513 size = newstate->cy+1;
2514 if (size < newstate->width - newstate->cx)
2515 size = newstate->width - newstate->cx;
2516 if (size < newstate->height - newstate->cy)
2517 size = newstate->height - newstate->cy;
2518 return FLASH_FRAME * (size+4);
2524 static int game_wants_statusbar(void)
2533 const struct game thegame = {
2541 TRUE, game_configure, custom_params,
2550 FALSE, game_text_format,
2557 game_free_drawstate,
2561 game_wants_statusbar,