16 * The standard user interface for Net simply has left- and
17 * right-button mouse clicks in a square rotate it one way or the
18 * other. We also provide, by #ifdef, a separate interface based on
19 * rotational dragging motions. I initially developed this for the
20 * Mac on the basis that it might work better than the click
21 * interface with only one mouse button available, but in fact
22 * found it to be quite strange and unintuitive. Apparently it
23 * works better on stylus-driven platforms such as Palm and
24 * PocketPC, though, so we enable it by default there.
30 #define MATMUL(xr,yr,m,x,y) do { \
31 float rx, ry, xx = (x), yy = (y), *mat = (m); \
32 rx = mat[0] * xx + mat[2] * yy; \
33 ry = mat[1] * xx + mat[3] * yy; \
34 (xr) = rx; (yr) = ry; \
37 /* Direction and other bitfields */
44 #define RLOOP (R << 6)
45 #define ULOOP (U << 6)
46 #define LLOOP (L << 6)
47 #define DLOOP (D << 6)
48 #define LOOP(dir) ((dir) << 6)
50 /* Rotations: Anticlockwise, Clockwise, Flip, general rotate */
51 #define A(x) ( (((x) & 0x07) << 1) | (((x) & 0x08) >> 3) )
52 #define C(x) ( (((x) & 0x0E) >> 1) | (((x) & 0x01) << 3) )
53 #define F(x) ( (((x) & 0x0C) >> 2) | (((x) & 0x03) << 2) )
54 #define ROT(x, n) ( ((n)&3) == 0 ? (x) : \
55 ((n)&3) == 1 ? A(x) : \
56 ((n)&3) == 2 ? F(x) : C(x) )
58 /* X and Y displacements */
59 #define X(x) ( (x) == R ? +1 : (x) == L ? -1 : 0 )
60 #define Y(x) ( (x) == D ? +1 : (x) == U ? -1 : 0 )
63 #define COUNT(x) ( (((x) & 0x08) >> 3) + (((x) & 0x04) >> 2) + \
64 (((x) & 0x02) >> 1) + ((x) & 0x01) )
66 #define PREFERRED_TILE_SIZE 32
67 #define TILE_SIZE (ds->tilesize)
70 #define WINDOW_OFFSET 4
72 #define WINDOW_OFFSET 16
75 #define ROTATE_TIME 0.13F
76 #define FLASH_FRAME 0.07F
78 /* Transform physical coords to game coords using game_drawstate ds */
79 #define GX(x) (((x) + ds->org_x) % ds->width)
80 #define GY(y) (((y) + ds->org_y) % ds->height)
81 /* ...and game coords to physical coords */
82 #define RX(x) (((x) + ds->width - ds->org_x) % ds->width)
83 #define RY(y) (((y) + ds->height - ds->org_y) % ds->height)
102 float barrier_probability;
106 int width, height, wrapping, completed;
107 int last_rotate_x, last_rotate_y, last_rotate_dir;
109 unsigned char *tiles;
110 unsigned char *barriers;
113 #define OFFSETWH(x2,y2,x1,y1,dir,width,height) \
114 ( (x2) = ((x1) + width + X((dir))) % width, \
115 (y2) = ((y1) + height + Y((dir))) % height)
117 #define OFFSET(x2,y2,x1,y1,dir,state) \
118 OFFSETWH(x2,y2,x1,y1,dir,(state)->width,(state)->height)
120 #define index(state, a, x, y) ( a[(y) * (state)->width + (x)] )
121 #define tile(state, x, y) index(state, (state)->tiles, x, y)
122 #define barrier(state, x, y) index(state, (state)->barriers, x, y)
128 static int xyd_cmp(const void *av, const void *bv) {
129 const struct xyd *a = (const struct xyd *)av;
130 const struct xyd *b = (const struct xyd *)bv;
139 if (a->direction < b->direction)
141 if (a->direction > b->direction)
146 static int xyd_cmp_nc(void *av, void *bv) { return xyd_cmp(av, bv); }
148 static struct xyd *new_xyd(int x, int y, int direction)
150 struct xyd *xyd = snew(struct xyd);
153 xyd->direction = direction;
157 /* ----------------------------------------------------------------------
158 * Manage game parameters.
160 static game_params *default_params(void)
162 game_params *ret = snew(game_params);
166 ret->wrapping = FALSE;
168 ret->barrier_probability = 0.0;
173 static const struct game_params net_presets[] = {
174 {5, 5, FALSE, TRUE, 0.0},
175 {7, 7, FALSE, TRUE, 0.0},
176 {9, 9, FALSE, TRUE, 0.0},
177 {11, 11, FALSE, TRUE, 0.0},
179 {13, 11, FALSE, TRUE, 0.0},
181 {5, 5, TRUE, TRUE, 0.0},
182 {7, 7, TRUE, TRUE, 0.0},
183 {9, 9, TRUE, TRUE, 0.0},
184 {11, 11, TRUE, TRUE, 0.0},
186 {13, 11, TRUE, TRUE, 0.0},
190 static int game_fetch_preset(int i, char **name, game_params **params)
195 if (i < 0 || i >= lenof(net_presets))
198 ret = snew(game_params);
199 *ret = net_presets[i];
201 sprintf(str, "%dx%d%s", ret->width, ret->height,
202 ret->wrapping ? " wrapping" : "");
209 static void free_params(game_params *params)
214 static game_params *dup_params(const game_params *params)
216 game_params *ret = snew(game_params);
217 *ret = *params; /* structure copy */
221 static void decode_params(game_params *ret, char const *string)
223 char const *p = string;
225 ret->width = atoi(p);
226 while (*p && isdigit((unsigned char)*p)) p++;
229 ret->height = atoi(p);
230 while (*p && isdigit((unsigned char)*p)) p++;
232 ret->height = ret->width;
238 ret->wrapping = TRUE;
239 } else if (*p == 'b') {
241 ret->barrier_probability = (float)atof(p);
242 while (*p && (*p == '.' || isdigit((unsigned char)*p))) p++;
243 } else if (*p == 'a') {
247 p++; /* skip any other gunk */
251 static char *encode_params(const game_params *params, int full)
256 len = sprintf(ret, "%dx%d", params->width, params->height);
257 if (params->wrapping)
259 if (full && params->barrier_probability)
260 len += sprintf(ret+len, "b%g", params->barrier_probability);
261 if (full && !params->unique)
263 assert(len < lenof(ret));
269 static config_item *game_configure(const game_params *params)
274 ret = snewn(6, config_item);
276 ret[0].name = "Width";
277 ret[0].type = C_STRING;
278 sprintf(buf, "%d", params->width);
279 ret[0].sval = dupstr(buf);
282 ret[1].name = "Height";
283 ret[1].type = C_STRING;
284 sprintf(buf, "%d", params->height);
285 ret[1].sval = dupstr(buf);
288 ret[2].name = "Walls wrap around";
289 ret[2].type = C_BOOLEAN;
291 ret[2].ival = params->wrapping;
293 ret[3].name = "Barrier probability";
294 ret[3].type = C_STRING;
295 sprintf(buf, "%g", params->barrier_probability);
296 ret[3].sval = dupstr(buf);
299 ret[4].name = "Ensure unique solution";
300 ret[4].type = C_BOOLEAN;
302 ret[4].ival = params->unique;
312 static game_params *custom_params(const config_item *cfg)
314 game_params *ret = snew(game_params);
316 ret->width = atoi(cfg[0].sval);
317 ret->height = atoi(cfg[1].sval);
318 ret->wrapping = cfg[2].ival;
319 ret->barrier_probability = (float)atof(cfg[3].sval);
320 ret->unique = cfg[4].ival;
325 static char *validate_params(const game_params *params, int full)
327 if (params->width <= 0 || params->height <= 0)
328 return "Width and height must both be greater than zero";
329 if (params->width <= 1 && params->height <= 1)
330 return "At least one of width and height must be greater than one";
331 if (params->barrier_probability < 0)
332 return "Barrier probability may not be negative";
333 if (params->barrier_probability > 1)
334 return "Barrier probability may not be greater than 1";
337 * Specifying either grid dimension as 2 in a wrapping puzzle
338 * makes it actually impossible to ensure a unique puzzle
343 * Without loss of generality, let us assume the puzzle _width_
344 * is 2, so we can conveniently discuss rows without having to
345 * say `rows/columns' all the time. (The height may be 2 as
346 * well, but that doesn't matter.)
348 * In each row, there are two edges between tiles: the inner
349 * edge (running down the centre of the grid) and the outer
350 * edge (the identified left and right edges of the grid).
352 * Lemma: In any valid 2xn puzzle there must be at least one
353 * row in which _exactly one_ of the inner edge and outer edge
356 * Proof: No row can have _both_ inner and outer edges
357 * connected, because this would yield a loop. So the only
358 * other way to falsify the lemma is for every row to have
359 * _neither_ the inner nor outer edge connected. But this
360 * means there is no connection at all between the left and
361 * right columns of the puzzle, so there are two disjoint
362 * subgraphs, which is also disallowed. []
364 * Given such a row, it is always possible to make the
365 * disconnected edge connected and the connected edge
366 * disconnected without changing the state of any other edge.
367 * (This is easily seen by case analysis on the various tiles:
368 * left-pointing and right-pointing endpoints can be exchanged,
369 * likewise T-pieces, and a corner piece can select its
370 * horizontal connectivity independently of its vertical.) This
371 * yields a distinct valid solution.
373 * Thus, for _every_ row in which exactly one of the inner and
374 * outer edge is connected, there are two valid states for that
375 * row, and hence the total number of solutions of the puzzle
376 * is at least 2^(number of such rows), and in particular is at
377 * least 2 since there must be at least one such row. []
379 if (full && params->unique && params->wrapping &&
380 (params->width == 2 || params->height == 2))
381 return "No wrapping puzzle with a width or height of 2 can have"
382 " a unique solution";
387 /* ----------------------------------------------------------------------
388 * Solver used to assure solution uniqueness during generation.
392 * Test cases I used while debugging all this were
394 * ./net --generate 1 13x11w#12300
395 * which expands under the non-unique grid generation rules to
396 * 13x11w:5eaade1bd222664436d5e2965c12656b1129dd825219e3274d558d5eb2dab5da18898e571d5a2987be79746bd95726c597447d6da96188c513add829da7681da954db113d3cd244
397 * and has two ambiguous areas.
399 * An even better one is
400 * 13x11w#507896411361192
402 * 13x11w:b7125b1aec598eb31bd58d82572bc11494e5dee4e8db2bdd29b88d41a16bdd996d2996ddec8c83741a1e8674e78328ba71737b8894a9271b1cd1399453d1952e43951d9b712822e
403 * and has an ambiguous area _and_ a situation where loop avoidance
404 * is a necessary deductive technique.
407 * 48x25w#820543338195187
409 * 48x25w:255989d14cdd185deaa753a93821a12edc1ab97943ac127e2685d7b8b3c48861b2192416139212b316eddd35de43714ebc7628d753db32e596284d9ec52c5a7dc1b4c811a655117d16dc28921b2b4161352cab1d89d18bc836b8b891d55ea4622a1251861b5bc9a8aa3e5bcd745c95229ca6c3b5e21d5832d397e917325793d7eb442dc351b2db2a52ba8e1651642275842d8871d5534aabc6d5b741aaa2d48ed2a7dbbb3151ddb49d5b9a7ed1ab98ee75d613d656dbba347bc514c84556b43a9bc65a3256ead792488b862a9d2a8a39b4255a4949ed7dbd79443292521265896b4399c95ede89d7c8c797a6a57791a849adea489359a158aa12e5dacce862b8333b7ebea7d344d1a3c53198864b73a9dedde7b663abb1b539e1e8853b1b7edb14a2a17ebaae4dbe63598a2e7e9a2dbdad415bc1d8cb88cbab5a8c82925732cd282e641ea3bd7d2c6e776de9117a26be86deb7c82c89524b122cb9397cd1acd2284e744ea62b9279bae85479ababe315c3ac29c431333395b24e6a1e3c43a2da42d4dce84aadd5b154aea555eaddcbd6e527d228c19388d9b424d94214555a7edbdeebe569d4a56dc51a86bd9963e377bb74752bd5eaa5761ba545e297b62a1bda46ab4aee423ad6c661311783cc18786d4289236563cb4a75ec67d481c14814994464cd1b87396dee63e5ab6e952cc584baa1d4c47cb557ec84dbb63d487c8728118673a166846dd3a4ebc23d6cb9c5827d96b4556e91899db32b517eda815ae271a8911bd745447121dc8d321557bc2a435ebec1bbac35b1a291669451174e6aa2218a4a9c5a6ca31ebc45d84e3a82c121e9ced7d55e9a
410 * which has a spot (far right) where slightly more complex loop
411 * avoidance is required.
415 unsigned char *marked;
421 static struct todo *todo_new(int maxsize)
423 struct todo *todo = snew(struct todo);
424 todo->marked = snewn(maxsize, unsigned char);
425 memset(todo->marked, 0, maxsize);
426 todo->buflen = maxsize + 1;
427 todo->buffer = snewn(todo->buflen, int);
428 todo->head = todo->tail = 0;
432 static void todo_free(struct todo *todo)
439 static void todo_add(struct todo *todo, int index)
441 if (todo->marked[index])
442 return; /* already on the list */
443 todo->marked[index] = TRUE;
444 todo->buffer[todo->tail++] = index;
445 if (todo->tail == todo->buflen)
449 static int todo_get(struct todo *todo) {
452 if (todo->head == todo->tail)
453 return -1; /* list is empty */
454 ret = todo->buffer[todo->head++];
455 if (todo->head == todo->buflen)
457 todo->marked[ret] = FALSE;
462 static int net_solver(int w, int h, unsigned char *tiles,
463 unsigned char *barriers, int wrapping)
465 unsigned char *tilestate;
466 unsigned char *edgestate;
475 * Set up the solver's data structures.
479 * tilestate stores the possible orientations of each tile.
480 * There are up to four of these, so we'll index the array in
481 * fours. tilestate[(y * w + x) * 4] and its three successive
482 * members give the possible orientations, clearing to 255 from
483 * the end as things are ruled out.
485 * In this loop we also count up the area of the grid (which is
486 * not _necessarily_ equal to w*h, because there might be one
487 * or more blank squares present. This will never happen in a
488 * grid generated _by_ this program, but it's worth keeping the
489 * solver as general as possible.)
491 tilestate = snewn(w * h * 4, unsigned char);
493 for (i = 0; i < w*h; i++) {
494 tilestate[i * 4] = tiles[i] & 0xF;
495 for (j = 1; j < 4; j++) {
496 if (tilestate[i * 4 + j - 1] == 255 ||
497 A(tilestate[i * 4 + j - 1]) == tilestate[i * 4])
498 tilestate[i * 4 + j] = 255;
500 tilestate[i * 4 + j] = A(tilestate[i * 4 + j - 1]);
507 * edgestate stores the known state of each edge. It is 0 for
508 * unknown, 1 for open (connected) and 2 for closed (not
511 * In principle we need only worry about each edge once each,
512 * but in fact it's easier to track each edge twice so that we
513 * can reference it from either side conveniently. Also I'm
514 * going to allocate _five_ bytes per tile, rather than the
515 * obvious four, so that I can index edgestate[(y*w+x) * 5 + d]
516 * where d is 1,2,4,8 and they never overlap.
518 edgestate = snewn((w * h - 1) * 5 + 9, unsigned char);
519 memset(edgestate, 0, (w * h - 1) * 5 + 9);
522 * deadends tracks which edges have dead ends on them. It is
523 * indexed by tile and direction: deadends[(y*w+x) * 5 + d]
524 * tells you whether heading out of tile (x,y) in direction d
525 * can reach a limited amount of the grid. Values are area+1
526 * (no dead end known) or less than that (can reach _at most_
527 * this many other tiles by heading this way out of this tile).
529 deadends = snewn((w * h - 1) * 5 + 9, int);
530 for (i = 0; i < (w * h - 1) * 5 + 9; i++)
531 deadends[i] = area+1;
534 * equivalence tracks which sets of tiles are known to be
535 * connected to one another, so we can avoid creating loops by
536 * linking together tiles which are already linked through
539 * This is a disjoint set forest structure: equivalence[i]
540 * contains the index of another member of the equivalence
541 * class containing i, or contains i itself for precisely one
542 * member in each such class. To find a representative member
543 * of the equivalence class containing i, you keep replacing i
544 * with equivalence[i] until it stops changing; then you go
545 * _back_ along the same path and point everything on it
546 * directly at the representative member so as to speed up
547 * future searches. Then you test equivalence between tiles by
548 * finding the representative of each tile and seeing if
549 * they're the same; and you create new equivalence (merge
550 * classes) by finding the representative of each tile and
551 * setting equivalence[one]=the_other.
553 equivalence = snew_dsf(w * h);
556 * On a non-wrapping grid, we instantly know that all the edges
557 * round the edge are closed.
560 for (i = 0; i < w; i++) {
561 edgestate[i * 5 + 2] = edgestate[((h-1) * w + i) * 5 + 8] = 2;
563 for (i = 0; i < h; i++) {
564 edgestate[(i * w + w-1) * 5 + 1] = edgestate[(i * w) * 5 + 4] = 2;
569 * If we have barriers available, we can mark those edges as
573 for (y = 0; y < h; y++) for (x = 0; x < w; x++) {
575 for (d = 1; d <= 8; d += d) {
576 if (barriers[y*w+x] & d) {
579 * In principle the barrier list should already
580 * contain each barrier from each side, but
581 * let's not take chances with our internal
584 OFFSETWH(x2, y2, x, y, d, w, h);
585 edgestate[(y*w+x) * 5 + d] = 2;
586 edgestate[(y2*w+x2) * 5 + F(d)] = 2;
593 * Since most deductions made by this solver are local (the
594 * exception is loop avoidance, where joining two tiles
595 * together on one side of the grid can theoretically permit a
596 * fresh deduction on the other), we can address the scaling
597 * problem inherent in iterating repeatedly over the entire
598 * grid by instead working with a to-do list.
600 todo = todo_new(w * h);
603 * Main deductive loop.
605 done_something = TRUE; /* prevent instant termination! */
610 * Take a tile index off the todo list and process it.
612 index = todo_get(todo);
615 * If we have run out of immediate things to do, we
616 * have no choice but to scan the whole grid for
617 * longer-range things we've missed. Hence, I now add
618 * every square on the grid back on to the to-do list.
619 * I also set `done_something' to FALSE at this point;
620 * if we later come back here and find it still FALSE,
621 * we will know we've scanned the entire grid without
622 * finding anything new to do, and we can terminate.
626 for (i = 0; i < w*h; i++)
628 done_something = FALSE;
630 index = todo_get(todo);
636 int d, ourclass = dsf_canonify(equivalence, y*w+x);
639 deadendmax[1] = deadendmax[2] = deadendmax[4] = deadendmax[8] = 0;
641 for (i = j = 0; i < 4 && tilestate[(y*w+x) * 4 + i] != 255; i++) {
643 int nnondeadends, nondeadends[4], deadendtotal;
644 int nequiv, equiv[5];
645 int val = tilestate[(y*w+x) * 4 + i];
648 nnondeadends = deadendtotal = 0;
651 for (d = 1; d <= 8; d += d) {
653 * Immediately rule out this orientation if it
654 * conflicts with any known edge.
656 if ((edgestate[(y*w+x) * 5 + d] == 1 && !(val & d)) ||
657 (edgestate[(y*w+x) * 5 + d] == 2 && (val & d)))
662 * Count up the dead-end statistics.
664 if (deadends[(y*w+x) * 5 + d] <= area) {
665 deadendtotal += deadends[(y*w+x) * 5 + d];
667 nondeadends[nnondeadends++] = d;
671 * Ensure we aren't linking to any tiles,
672 * through edges not already known to be
673 * open, which create a loop.
675 if (edgestate[(y*w+x) * 5 + d] == 0) {
678 OFFSETWH(x2, y2, x, y, d, w, h);
679 c = dsf_canonify(equivalence, y2*w+x2);
680 for (k = 0; k < nequiv; k++)
691 if (nnondeadends == 0) {
693 * If this orientation links together dead-ends
694 * with a total area of less than the entire
695 * grid, it is invalid.
697 * (We add 1 to deadendtotal because of the
698 * tile itself, of course; one tile linking
699 * dead ends of size 2 and 3 forms a subnetwork
700 * with a total area of 6, not 5.)
702 if (deadendtotal > 0 && deadendtotal+1 < area)
704 } else if (nnondeadends == 1) {
706 * If this orientation links together one or
707 * more dead-ends with precisely one
708 * non-dead-end, then we may have to mark that
709 * non-dead-end as a dead end going the other
710 * way. However, it depends on whether all
711 * other orientations share the same property.
714 if (deadendmax[nondeadends[0]] < deadendtotal)
715 deadendmax[nondeadends[0]] = deadendtotal;
718 * If this orientation links together two or
719 * more non-dead-ends, then we can rule out the
720 * possibility of putting in new dead-end
721 * markings in those directions.
724 for (k = 0; k < nnondeadends; k++)
725 deadendmax[nondeadends[k]] = area+1;
729 tilestate[(y*w+x) * 4 + j++] = val;
730 #ifdef SOLVER_DIAGNOSTICS
732 printf("ruling out orientation %x at %d,%d\n", val, x, y);
736 assert(j > 0); /* we can't lose _all_ possibilities! */
739 done_something = TRUE;
742 * We have ruled out at least one tile orientation.
743 * Make sure the rest are blanked.
746 tilestate[(y*w+x) * 4 + j++] = 255;
750 * Now go through the tile orientations again and see
751 * if we've deduced anything new about any edges.
757 for (i = 0; i < 4 && tilestate[(y*w+x) * 4 + i] != 255; i++) {
758 a &= tilestate[(y*w+x) * 4 + i];
759 o |= tilestate[(y*w+x) * 4 + i];
761 for (d = 1; d <= 8; d += d)
762 if (edgestate[(y*w+x) * 5 + d] == 0) {
764 OFFSETWH(x2, y2, x, y, d, w, h);
767 /* This edge is open in all orientations. */
768 #ifdef SOLVER_DIAGNOSTICS
769 printf("marking edge %d,%d:%d open\n", x, y, d);
771 edgestate[(y*w+x) * 5 + d] = 1;
772 edgestate[(y2*w+x2) * 5 + d2] = 1;
773 dsf_merge(equivalence, y*w+x, y2*w+x2);
774 done_something = TRUE;
775 todo_add(todo, y2*w+x2);
776 } else if (!(o & d)) {
777 /* This edge is closed in all orientations. */
778 #ifdef SOLVER_DIAGNOSTICS
779 printf("marking edge %d,%d:%d closed\n", x, y, d);
781 edgestate[(y*w+x) * 5 + d] = 2;
782 edgestate[(y2*w+x2) * 5 + d2] = 2;
783 done_something = TRUE;
784 todo_add(todo, y2*w+x2);
791 * Now check the dead-end markers and see if any of
792 * them has lowered from the real ones.
794 for (d = 1; d <= 8; d += d) {
796 OFFSETWH(x2, y2, x, y, d, w, h);
798 if (deadendmax[d] > 0 &&
799 deadends[(y2*w+x2) * 5 + d2] > deadendmax[d]) {
800 #ifdef SOLVER_DIAGNOSTICS
801 printf("setting dead end value %d,%d:%d to %d\n",
802 x2, y2, d2, deadendmax[d]);
804 deadends[(y2*w+x2) * 5 + d2] = deadendmax[d];
805 done_something = TRUE;
806 todo_add(todo, y2*w+x2);
814 * Mark all completely determined tiles as locked.
817 for (i = 0; i < w*h; i++) {
818 if (tilestate[i * 4 + 1] == 255) {
819 assert(tilestate[i * 4 + 0] != 255);
820 tiles[i] = tilestate[i * 4] | LOCKED;
828 * Free up working space.
839 /* ----------------------------------------------------------------------
840 * Randomly select a new game description.
844 * Function to randomly perturb an ambiguous section in a grid, to
845 * attempt to ensure unique solvability.
847 static void perturb(int w, int h, unsigned char *tiles, int wrapping,
848 random_state *rs, int startx, int starty, int startd)
850 struct xyd *perimeter, *perim2, *loop[2], looppos[2];
851 int nperim, perimsize, nloop[2], loopsize[2];
855 * We know that the tile at (startx,starty) is part of an
856 * ambiguous section, and we also know that its neighbour in
857 * direction startd is fully specified. We begin by tracing all
858 * the way round the ambiguous area.
860 nperim = perimsize = 0;
865 #ifdef PERTURB_DIAGNOSTICS
866 printf("perturb %d,%d:%d\n", x, y, d);
871 if (nperim >= perimsize) {
872 perimsize = perimsize * 3 / 2 + 32;
873 perimeter = sresize(perimeter, perimsize, struct xyd);
875 perimeter[nperim].x = x;
876 perimeter[nperim].y = y;
877 perimeter[nperim].direction = d;
879 #ifdef PERTURB_DIAGNOSTICS
880 printf("perimeter: %d,%d:%d\n", x, y, d);
884 * First, see if we can simply turn left from where we are
885 * and find another locked square.
888 OFFSETWH(x2, y2, x, y, d2, w, h);
889 if ((!wrapping && (abs(x2-x) > 1 || abs(y2-y) > 1)) ||
890 (tiles[y2*w+x2] & LOCKED)) {
894 * Failing that, step left into the new square and look
899 OFFSETWH(x2, y2, x, y, d, w, h);
900 if ((wrapping || (abs(x2-x) <= 1 && abs(y2-y) <= 1)) &&
901 !(tiles[y2*w+x2] & LOCKED)) {
903 * And failing _that_, we're going to have to step
904 * forward into _that_ square and look right at the
905 * same locked square as we started with.
913 } while (x != startx || y != starty || d != startd);
916 * Our technique for perturbing this ambiguous area is to
917 * search round its edge for a join we can make: that is, an
918 * edge on the perimeter which is (a) not currently connected,
919 * and (b) connecting it would not yield a full cross on either
920 * side. Then we make that join, search round the network to
921 * find the loop thus constructed, and sever the loop at a
922 * randomly selected other point.
924 perim2 = snewn(nperim, struct xyd);
925 memcpy(perim2, perimeter, nperim * sizeof(struct xyd));
926 /* Shuffle the perimeter, so as to search it without directional bias. */
927 shuffle(perim2, nperim, sizeof(*perim2), rs);
928 for (i = 0; i < nperim; i++) {
933 d = perim2[i].direction;
935 OFFSETWH(x2, y2, x, y, d, w, h);
936 if (!wrapping && (abs(x2-x) > 1 || abs(y2-y) > 1))
937 continue; /* can't link across non-wrapping border */
938 if (tiles[y*w+x] & d)
939 continue; /* already linked in this direction! */
940 if (((tiles[y*w+x] | d) & 15) == 15)
941 continue; /* can't turn this tile into a cross */
942 if (((tiles[y2*w+x2] | F(d)) & 15) == 15)
943 continue; /* can't turn other tile into a cross */
946 * We've found the point at which we're going to make a new
949 #ifdef PERTURB_DIAGNOSTICS
950 printf("linking %d,%d:%d\n", x, y, d);
953 tiles[y2*w+x2] |= F(d);
961 return; /* nothing we can do! */
965 * Now we've constructed a new link, we need to find the entire
966 * loop of which it is a part.
968 * In principle, this involves doing a complete search round
969 * the network. However, I anticipate that in the vast majority
970 * of cases the loop will be quite small, so what I'm going to
971 * do is make _two_ searches round the network in parallel, one
972 * keeping its metaphorical hand on the left-hand wall while
973 * the other keeps its hand on the right. As soon as one of
974 * them gets back to its starting point, I abandon the other.
976 for (i = 0; i < 2; i++) {
977 loopsize[i] = nloop[i] = 0;
981 looppos[i].direction = d;
984 for (i = 0; i < 2; i++) {
989 d = looppos[i].direction;
991 OFFSETWH(x2, y2, x, y, d, w, h);
994 * Add this path segment to the loop, unless it exactly
995 * reverses the previous one on the loop in which case
996 * we take it away again.
998 #ifdef PERTURB_DIAGNOSTICS
999 printf("looppos[%d] = %d,%d:%d\n", i, x, y, d);
1002 loop[i][nloop[i]-1].x == x2 &&
1003 loop[i][nloop[i]-1].y == y2 &&
1004 loop[i][nloop[i]-1].direction == F(d)) {
1005 #ifdef PERTURB_DIAGNOSTICS
1006 printf("removing path segment %d,%d:%d from loop[%d]\n",
1011 if (nloop[i] >= loopsize[i]) {
1012 loopsize[i] = loopsize[i] * 3 / 2 + 32;
1013 loop[i] = sresize(loop[i], loopsize[i], struct xyd);
1015 #ifdef PERTURB_DIAGNOSTICS
1016 printf("adding path segment %d,%d:%d to loop[%d]\n",
1019 loop[i][nloop[i]++] = looppos[i];
1022 #ifdef PERTURB_DIAGNOSTICS
1023 printf("tile at new location is %x\n", tiles[y2*w+x2] & 0xF);
1026 for (j = 0; j < 4; j++) {
1031 #ifdef PERTURB_DIAGNOSTICS
1032 printf("trying dir %d\n", d);
1034 if (tiles[y2*w+x2] & d) {
1037 looppos[i].direction = d;
1043 assert(nloop[i] > 0);
1045 if (looppos[i].x == loop[i][0].x &&
1046 looppos[i].y == loop[i][0].y &&
1047 looppos[i].direction == loop[i][0].direction) {
1048 #ifdef PERTURB_DIAGNOSTICS
1049 printf("loop %d finished tracking\n", i);
1053 * Having found our loop, we now sever it at a
1054 * randomly chosen point - absolutely any will do -
1055 * which is not the one we joined it at to begin
1056 * with. Conveniently, the one we joined it at is
1057 * loop[i][0], so we just avoid that one.
1059 j = random_upto(rs, nloop[i]-1) + 1;
1062 d = loop[i][j].direction;
1063 OFFSETWH(x2, y2, x, y, d, w, h);
1065 tiles[y2*w+x2] &= ~F(d);
1077 * Finally, we must mark the entire disputed section as locked,
1078 * to prevent the perturb function being called on it multiple
1081 * To do this, we _sort_ the perimeter of the area. The
1082 * existing xyd_cmp function will arrange things into columns
1083 * for us, in such a way that each column has the edges in
1084 * vertical order. Then we can work down each column and fill
1085 * in all the squares between an up edge and a down edge.
1087 qsort(perimeter, nperim, sizeof(struct xyd), xyd_cmp);
1089 for (i = 0; i <= nperim; i++) {
1090 if (i == nperim || perimeter[i].x > x) {
1092 * Fill in everything from the last Up edge to the
1093 * bottom of the grid, if necessary.
1097 #ifdef PERTURB_DIAGNOSTICS
1098 printf("resolved: locking tile %d,%d\n", x, y);
1100 tiles[y * w + x] |= LOCKED;
1113 if (perimeter[i].direction == U) {
1116 } else if (perimeter[i].direction == D) {
1118 * Fill in everything from the last Up edge to here.
1120 assert(x == perimeter[i].x && y <= perimeter[i].y);
1121 while (y <= perimeter[i].y) {
1122 #ifdef PERTURB_DIAGNOSTICS
1123 printf("resolved: locking tile %d,%d\n", x, y);
1125 tiles[y * w + x] |= LOCKED;
1135 static int *compute_loops_inner(int w, int h, int wrapping,
1136 const unsigned char *tiles,
1137 const unsigned char *barriers);
1139 static char *new_game_desc(const game_params *params, random_state *rs,
1140 char **aux, int interactive)
1142 tree234 *possibilities, *barriertree;
1143 int w, h, x, y, cx, cy, nbarriers;
1144 unsigned char *tiles, *barriers;
1153 tiles = snewn(w * h, unsigned char);
1154 barriers = snewn(w * h, unsigned char);
1158 memset(tiles, 0, w * h);
1159 memset(barriers, 0, w * h);
1162 * Construct the unshuffled grid.
1164 * To do this, we simply start at the centre point, repeatedly
1165 * choose a random possibility out of the available ways to
1166 * extend a used square into an unused one, and do it. After
1167 * extending the third line out of a square, we remove the
1168 * fourth from the possibilities list to avoid any full-cross
1169 * squares (which would make the game too easy because they
1170 * only have one orientation).
1172 * The slightly worrying thing is the avoidance of full-cross
1173 * squares. Can this cause our unsophisticated construction
1174 * algorithm to paint itself into a corner, by getting into a
1175 * situation where there are some unreached squares and the
1176 * only way to reach any of them is to extend a T-piece into a
1179 * Answer: no it can't, and here's a proof.
1181 * Any contiguous group of such unreachable squares must be
1182 * surrounded on _all_ sides by T-pieces pointing away from the
1183 * group. (If not, then there is a square which can be extended
1184 * into one of the `unreachable' ones, and so it wasn't
1185 * unreachable after all.) In particular, this implies that
1186 * each contiguous group of unreachable squares must be
1187 * rectangular in shape (any deviation from that yields a
1188 * non-T-piece next to an `unreachable' square).
1190 * So we have a rectangle of unreachable squares, with T-pieces
1191 * forming a solid border around the rectangle. The corners of
1192 * that border must be connected (since every tile connects all
1193 * the lines arriving in it), and therefore the border must
1194 * form a closed loop around the rectangle.
1196 * But this can't have happened in the first place, since we
1197 * _know_ we've avoided creating closed loops! Hence, no such
1198 * situation can ever arise, and the naive grid construction
1199 * algorithm will guaranteeably result in a complete grid
1200 * containing no unreached squares, no full crosses _and_ no
1203 possibilities = newtree234(xyd_cmp_nc);
1206 add234(possibilities, new_xyd(cx, cy, R));
1208 add234(possibilities, new_xyd(cx, cy, U));
1210 add234(possibilities, new_xyd(cx, cy, L));
1212 add234(possibilities, new_xyd(cx, cy, D));
1214 while (count234(possibilities) > 0) {
1217 int x1, y1, d1, x2, y2, d2, d;
1220 * Extract a randomly chosen possibility from the list.
1222 i = random_upto(rs, count234(possibilities));
1223 xyd = delpos234(possibilities, i);
1226 d1 = xyd->direction;
1229 OFFSET(x2, y2, x1, y1, d1, params);
1231 #ifdef GENERATION_DIAGNOSTICS
1232 printf("picked (%d,%d,%c) <-> (%d,%d,%c)\n",
1233 x1, y1, "0RU3L567D9abcdef"[d1], x2, y2, "0RU3L567D9abcdef"[d2]);
1237 * Make the connection. (We should be moving to an as yet
1240 index(params, tiles, x1, y1) |= d1;
1241 assert(index(params, tiles, x2, y2) == 0);
1242 index(params, tiles, x2, y2) |= d2;
1245 * If we have created a T-piece, remove its last
1248 if (COUNT(index(params, tiles, x1, y1)) == 3) {
1249 struct xyd xyd1, *xydp;
1253 xyd1.direction = 0x0F ^ index(params, tiles, x1, y1);
1255 xydp = find234(possibilities, &xyd1, NULL);
1258 #ifdef GENERATION_DIAGNOSTICS
1259 printf("T-piece; removing (%d,%d,%c)\n",
1260 xydp->x, xydp->y, "0RU3L567D9abcdef"[xydp->direction]);
1262 del234(possibilities, xydp);
1268 * Remove all other possibilities that were pointing at the
1269 * tile we've just moved into.
1271 for (d = 1; d < 0x10; d <<= 1) {
1273 struct xyd xyd1, *xydp;
1275 OFFSET(x3, y3, x2, y2, d, params);
1280 xyd1.direction = d3;
1282 xydp = find234(possibilities, &xyd1, NULL);
1285 #ifdef GENERATION_DIAGNOSTICS
1286 printf("Loop avoidance; removing (%d,%d,%c)\n",
1287 xydp->x, xydp->y, "0RU3L567D9abcdef"[xydp->direction]);
1289 del234(possibilities, xydp);
1295 * Add new possibilities to the list for moving _out_ of
1296 * the tile we have just moved into.
1298 for (d = 1; d < 0x10; d <<= 1) {
1302 continue; /* we've got this one already */
1304 if (!params->wrapping) {
1305 if (d == U && y2 == 0)
1307 if (d == D && y2 == h-1)
1309 if (d == L && x2 == 0)
1311 if (d == R && x2 == w-1)
1315 OFFSET(x3, y3, x2, y2, d, params);
1317 if (index(params, tiles, x3, y3))
1318 continue; /* this would create a loop */
1320 #ifdef GENERATION_DIAGNOSTICS
1321 printf("New frontier; adding (%d,%d,%c)\n",
1322 x2, y2, "0RU3L567D9abcdef"[d]);
1324 add234(possibilities, new_xyd(x2, y2, d));
1327 /* Having done that, we should have no possibilities remaining. */
1328 assert(count234(possibilities) == 0);
1329 freetree234(possibilities);
1331 if (params->unique) {
1335 * Run the solver to check unique solubility.
1337 while (!net_solver(w, h, tiles, NULL, params->wrapping)) {
1341 * We expect (in most cases) that most of the grid will
1342 * be uniquely specified already, and the remaining
1343 * ambiguous sections will be small and separate. So
1344 * our strategy is to find each individual such
1345 * section, and perform a perturbation on the network
1348 for (y = 0; y < h; y++) for (x = 0; x < w; x++) {
1349 if (x+1 < w && ((tiles[y*w+x] ^ tiles[y*w+x+1]) & LOCKED)) {
1351 if (tiles[y*w+x] & LOCKED)
1352 perturb(w, h, tiles, params->wrapping, rs, x+1, y, L);
1354 perturb(w, h, tiles, params->wrapping, rs, x, y, R);
1356 if (y+1 < h && ((tiles[y*w+x] ^ tiles[(y+1)*w+x]) & LOCKED)) {
1358 if (tiles[y*w+x] & LOCKED)
1359 perturb(w, h, tiles, params->wrapping, rs, x, y+1, U);
1361 perturb(w, h, tiles, params->wrapping, rs, x, y, D);
1366 * Now n counts the number of ambiguous sections we
1367 * have fiddled with. If we haven't managed to decrease
1368 * it from the last time we ran the solver, give up and
1369 * regenerate the entire grid.
1371 if (prevn != -1 && prevn <= n)
1372 goto begin_generation; /* (sorry) */
1378 * The solver will have left a lot of LOCKED bits lying
1379 * around in the tiles array. Remove them.
1381 for (x = 0; x < w*h; x++)
1382 tiles[x] &= ~LOCKED;
1386 * Now compute a list of the possible barrier locations.
1388 barriertree = newtree234(xyd_cmp_nc);
1389 for (y = 0; y < h; y++) {
1390 for (x = 0; x < w; x++) {
1392 if (!(index(params, tiles, x, y) & R) &&
1393 (params->wrapping || x < w-1))
1394 add234(barriertree, new_xyd(x, y, R));
1395 if (!(index(params, tiles, x, y) & D) &&
1396 (params->wrapping || y < h-1))
1397 add234(barriertree, new_xyd(x, y, D));
1402 * Save the unshuffled grid in aux.
1408 solution = snewn(w * h + 1, char);
1409 for (i = 0; i < w * h; i++)
1410 solution[i] = "0123456789abcdef"[tiles[i] & 0xF];
1411 solution[w*h] = '\0';
1417 * Now shuffle the grid.
1419 * In order to avoid accidentally generating an already-solved
1420 * grid, we will reshuffle as necessary to ensure that at least
1421 * one edge has a mismatched connection.
1423 * This can always be done, since validate_params() enforces a
1424 * grid area of at least 2 and our generator never creates
1425 * either type of rotationally invariant tile (cross and
1426 * blank). Hence there must be at least one edge separating
1427 * distinct tiles, and it must be possible to find orientations
1428 * of those tiles such that one tile is trying to connect
1429 * through that edge and the other is not.
1431 * (We could be more subtle, and allow the shuffle to generate
1432 * a grid in which all tiles match up locally and the only
1433 * criterion preventing the grid from being already solved is
1434 * connectedness. However, that would take more effort, and
1435 * it's easier to simply make sure every grid is _obviously_
1438 * We also require that our shuffle produces no loops in the
1439 * initial grid state, because it's a bit rude to light up a 'HEY,
1440 * YOU DID SOMETHING WRONG!' indicator when the user hasn't even
1441 * had a chance to do _anything_ yet. This also is possible just
1442 * by retrying the whole shuffle on failure, because it's clear
1443 * that at least one non-solved shuffle with no loops must exist.
1444 * (Proof: take the _solved_ state of the puzzle, and rotate one
1448 int mismatches, prev_loopsquares, this_loopsquares, i;
1452 for (y = 0; y < h; y++) {
1453 for (x = 0; x < w; x++) {
1454 int orig = index(params, tiles, x, y);
1455 int rot = random_upto(rs, 4);
1456 index(params, tiles, x, y) = ROT(orig, rot);
1461 * Check for loops, and try to fix them by reshuffling just
1462 * the squares involved.
1464 prev_loopsquares = w*h+1;
1466 loops = compute_loops_inner(w, h, params->wrapping, tiles, NULL);
1467 this_loopsquares = 0;
1468 for (i = 0; i < w*h; i++) {
1470 int orig = tiles[i];
1471 int rot = random_upto(rs, 4);
1472 tiles[i] = ROT(orig, rot);
1477 if (this_loopsquares > prev_loopsquares) {
1479 * We're increasing rather than reducing the number of
1480 * loops. Give up and go back to the full shuffle.
1484 if (this_loopsquares == 0)
1486 prev_loopsquares = this_loopsquares;
1491 * I can't even be bothered to check for mismatches across
1492 * a wrapping edge, so I'm just going to enforce that there
1493 * must be a mismatch across a non-wrapping edge, which is
1494 * still always possible.
1496 for (y = 0; y < h; y++) for (x = 0; x < w; x++) {
1497 if (x+1 < w && ((ROT(index(params, tiles, x, y), 2) ^
1498 index(params, tiles, x+1, y)) & L))
1500 if (y+1 < h && ((ROT(index(params, tiles, x, y), 2) ^
1501 index(params, tiles, x, y+1)) & U))
1505 if (mismatches == 0)
1513 * And now choose barrier locations. (We carefully do this
1514 * _after_ shuffling, so that changing the barrier rate in the
1515 * params while keeping the random seed the same will give the
1516 * same shuffled grid and _only_ change the barrier locations.
1517 * Also the way we choose barrier locations, by repeatedly
1518 * choosing one possibility from the list until we have enough,
1519 * is designed to ensure that raising the barrier rate while
1520 * keeping the seed the same will provide a superset of the
1521 * previous barrier set - i.e. if you ask for 10 barriers, and
1522 * then decide that's still too hard and ask for 20, you'll get
1523 * the original 10 plus 10 more, rather than getting 20 new
1524 * ones and the chance of remembering your first 10.)
1526 nbarriers = (int)(params->barrier_probability * count234(barriertree));
1527 assert(nbarriers >= 0 && nbarriers <= count234(barriertree));
1529 while (nbarriers > 0) {
1532 int x1, y1, d1, x2, y2, d2;
1535 * Extract a randomly chosen barrier from the list.
1537 i = random_upto(rs, count234(barriertree));
1538 xyd = delpos234(barriertree, i);
1540 assert(xyd != NULL);
1544 d1 = xyd->direction;
1547 OFFSET(x2, y2, x1, y1, d1, params);
1550 index(params, barriers, x1, y1) |= d1;
1551 index(params, barriers, x2, y2) |= d2;
1557 * Clean up the rest of the barrier list.
1562 while ( (xyd = delpos234(barriertree, 0)) != NULL)
1565 freetree234(barriertree);
1569 * Finally, encode the grid into a string game description.
1571 * My syntax is extremely simple: each square is encoded as a
1572 * hex digit in which bit 0 means a connection on the right,
1573 * bit 1 means up, bit 2 left and bit 3 down. (i.e. the same
1574 * encoding as used internally). Each digit is followed by
1575 * optional barrier indicators: `v' means a vertical barrier to
1576 * the right of it, and `h' means a horizontal barrier below
1579 desc = snewn(w * h * 3 + 1, char);
1581 for (y = 0; y < h; y++) {
1582 for (x = 0; x < w; x++) {
1583 *p++ = "0123456789abcdef"[index(params, tiles, x, y)];
1584 if ((params->wrapping || x < w-1) &&
1585 (index(params, barriers, x, y) & R))
1587 if ((params->wrapping || y < h-1) &&
1588 (index(params, barriers, x, y) & D))
1592 assert(p - desc <= w*h*3);
1601 static char *validate_desc(const game_params *params, const char *desc)
1603 int w = params->width, h = params->height;
1606 for (i = 0; i < w*h; i++) {
1607 if (*desc >= '0' && *desc <= '9')
1609 else if (*desc >= 'a' && *desc <= 'f')
1611 else if (*desc >= 'A' && *desc <= 'F')
1614 return "Game description shorter than expected";
1616 return "Game description contained unexpected character";
1618 while (*desc == 'h' || *desc == 'v')
1622 return "Game description longer than expected";
1627 /* ----------------------------------------------------------------------
1628 * Construct an initial game state, given a description and parameters.
1631 static game_state *new_game(midend *me, const game_params *params,
1637 assert(params->width > 0 && params->height > 0);
1638 assert(params->width > 1 || params->height > 1);
1641 * Create a blank game state.
1643 state = snew(game_state);
1644 w = state->width = params->width;
1645 h = state->height = params->height;
1646 state->wrapping = params->wrapping;
1647 state->last_rotate_dir = state->last_rotate_x = state->last_rotate_y = 0;
1648 state->completed = state->used_solve = FALSE;
1649 state->tiles = snewn(state->width * state->height, unsigned char);
1650 memset(state->tiles, 0, state->width * state->height);
1651 state->barriers = snewn(state->width * state->height, unsigned char);
1652 memset(state->barriers, 0, state->width * state->height);
1655 * Parse the game description into the grid.
1657 for (y = 0; y < h; y++) {
1658 for (x = 0; x < w; x++) {
1659 if (*desc >= '0' && *desc <= '9')
1660 tile(state, x, y) = *desc - '0';
1661 else if (*desc >= 'a' && *desc <= 'f')
1662 tile(state, x, y) = *desc - 'a' + 10;
1663 else if (*desc >= 'A' && *desc <= 'F')
1664 tile(state, x, y) = *desc - 'A' + 10;
1667 while (*desc == 'h' || *desc == 'v') {
1674 OFFSET(x2, y2, x, y, d1, state);
1677 barrier(state, x, y) |= d1;
1678 barrier(state, x2, y2) |= d2;
1686 * Set up border barriers if this is a non-wrapping game.
1688 if (!state->wrapping) {
1689 for (x = 0; x < state->width; x++) {
1690 barrier(state, x, 0) |= U;
1691 barrier(state, x, state->height-1) |= D;
1693 for (y = 0; y < state->height; y++) {
1694 barrier(state, 0, y) |= L;
1695 barrier(state, state->width-1, y) |= R;
1699 * We check whether this is de-facto a non-wrapping game
1700 * despite the parameters, in case we were passed the
1701 * description of a non-wrapping game. This is so that we
1702 * can change some aspects of the UI behaviour.
1704 state->wrapping = FALSE;
1705 for (x = 0; x < state->width; x++)
1706 if (!(barrier(state, x, 0) & U) ||
1707 !(barrier(state, x, state->height-1) & D))
1708 state->wrapping = TRUE;
1709 for (y = 0; y < state->height; y++)
1710 if (!(barrier(state, 0, y) & L) ||
1711 !(barrier(state, state->width-1, y) & R))
1712 state->wrapping = TRUE;
1718 static game_state *dup_game(const game_state *state)
1722 ret = snew(game_state);
1723 ret->width = state->width;
1724 ret->height = state->height;
1725 ret->wrapping = state->wrapping;
1726 ret->completed = state->completed;
1727 ret->used_solve = state->used_solve;
1728 ret->last_rotate_dir = state->last_rotate_dir;
1729 ret->last_rotate_x = state->last_rotate_x;
1730 ret->last_rotate_y = state->last_rotate_y;
1731 ret->tiles = snewn(state->width * state->height, unsigned char);
1732 memcpy(ret->tiles, state->tiles, state->width * state->height);
1733 ret->barriers = snewn(state->width * state->height, unsigned char);
1734 memcpy(ret->barriers, state->barriers, state->width * state->height);
1739 static void free_game(game_state *state)
1741 sfree(state->tiles);
1742 sfree(state->barriers);
1746 static char *solve_game(const game_state *state, const game_state *currstate,
1747 const char *aux, char **error)
1749 unsigned char *tiles;
1751 int retlen, retsize;
1754 tiles = snewn(state->width * state->height, unsigned char);
1758 * Run the internal solver on the provided grid. This might
1759 * not yield a complete solution.
1761 memcpy(tiles, state->tiles, state->width * state->height);
1762 net_solver(state->width, state->height, tiles,
1763 state->barriers, state->wrapping);
1765 for (i = 0; i < state->width * state->height; i++) {
1768 if (c >= '0' && c <= '9')
1770 else if (c >= 'a' && c <= 'f')
1771 tiles[i] = c - 'a' + 10;
1772 else if (c >= 'A' && c <= 'F')
1773 tiles[i] = c - 'A' + 10;
1780 * Now construct a string which can be passed to execute_move()
1781 * to transform the current grid into the solved one.
1784 ret = snewn(retsize, char);
1786 ret[retlen++] = 'S';
1788 for (i = 0; i < state->width * state->height; i++) {
1789 int from = currstate->tiles[i], to = tiles[i];
1790 int ft = from & (R|L|U|D), tt = to & (R|L|U|D);
1791 int x = i % state->width, y = i / state->width;
1793 char buf[80], *p = buf;
1796 continue; /* nothing needs doing at all */
1799 * To transform this tile into the desired tile: first
1800 * unlock the tile if it's locked, then rotate it if
1801 * necessary, then lock it if necessary.
1804 p += sprintf(p, ";L%d,%d", x, y);
1808 else if (tt == C(ft))
1810 else if (tt == F(ft))
1817 p += sprintf(p, ";%c%d,%d", chr, x, y);
1820 p += sprintf(p, ";L%d,%d", x, y);
1823 if (retlen + (p - buf) >= retsize) {
1824 retsize = retlen + (p - buf) + 512;
1825 ret = sresize(ret, retsize, char);
1827 memcpy(ret+retlen, buf, p - buf);
1832 assert(retlen < retsize);
1834 ret = sresize(ret, retlen+1, char);
1841 static int game_can_format_as_text_now(const game_params *params)
1846 static char *game_text_format(const game_state *state)
1851 /* ----------------------------------------------------------------------
1856 * Compute which squares are reachable from the centre square, as a
1857 * quick visual aid to determining how close the game is to
1858 * completion. This is also a simple way to tell if the game _is_
1859 * completed - just call this function and see whether every square
1862 static unsigned char *compute_active(const game_state *state, int cx, int cy)
1864 unsigned char *active;
1868 active = snewn(state->width * state->height, unsigned char);
1869 memset(active, 0, state->width * state->height);
1872 * We only store (x,y) pairs in todo, but it's easier to reuse
1873 * xyd_cmp and just store direction 0 every time.
1875 todo = newtree234(xyd_cmp_nc);
1876 index(state, active, cx, cy) = ACTIVE;
1877 add234(todo, new_xyd(cx, cy, 0));
1879 while ( (xyd = delpos234(todo, 0)) != NULL) {
1880 int x1, y1, d1, x2, y2, d2;
1886 for (d1 = 1; d1 < 0x10; d1 <<= 1) {
1887 OFFSET(x2, y2, x1, y1, d1, state);
1891 * If the next tile in this direction is connected to
1892 * us, and there isn't a barrier in the way, and it
1893 * isn't already marked active, then mark it active and
1894 * add it to the to-examine list.
1896 if ((tile(state, x1, y1) & d1) &&
1897 (tile(state, x2, y2) & d2) &&
1898 !(barrier(state, x1, y1) & d1) &&
1899 !index(state, active, x2, y2)) {
1900 index(state, active, x2, y2) = ACTIVE;
1901 add234(todo, new_xyd(x2, y2, 0));
1905 /* Now we expect the todo list to have shrunk to zero size. */
1906 assert(count234(todo) == 0);
1912 static int *compute_loops_inner(int w, int h, int wrapping,
1913 const unsigned char *tiles,
1914 const unsigned char *barriers)
1920 * The loop-detecting algorithm I use here is not quite the same
1921 * one as I've used in Slant and Loopy. Those two puzzles use a
1922 * very similar algorithm which works by finding connected
1923 * components, not of the graph _vertices_, but of the pieces of
1924 * space in between them. You divide the plane into maximal areas
1925 * that can't be intersected by a grid edge (faces in Loopy,
1926 * diamond shapes centred on a grid edge in Slant); you form a dsf
1927 * over those areas, and unify any pair _not_ separated by a graph
1928 * edge; then you've identified the connected components of the
1929 * space, and can now immediately tell whether an edge is part of
1930 * a loop or not by checking whether the pieces of space on either
1931 * side of it are in the same component.
1933 * In Net, this doesn't work reliably, because of the toroidal
1934 * wrapping mode. A torus has non-trivial homology, which is to
1935 * say, there can exist a closed loop on its surface which is not
1936 * the boundary of any proper subset of the torus's area. For
1937 * example, consider the 'loop' consisting of a straight vertical
1938 * line going off the top of the grid and coming back on the
1939 * bottom to join up with itself. This certainly wants to be
1940 * marked as a loop, but it won't be detected as one by the above
1941 * algorithm, because all the area of the grid is still connected
1942 * via the left- and right-hand edges, so the two sides of the
1943 * loop _are_ in the same equivalence class.
1945 * The replacement algorithm I use here is also dsf-based, but the
1946 * dsf is now over _sides of edges_. That is to say, on a general
1947 * graph, you would have two dsf elements per edge of the graph.
1948 * The unification rule is: for each vertex, iterate round the
1949 * edges leaving that vertex in cyclic order, and dsf-unify the
1950 * _near sides_ of each pair of adjacent edges. The effect of this
1951 * is to trace round the outside edge of each connected component
1952 * of the graph (this time of the actual graph, not the space
1953 * between), so that the outline of each component becomes its own
1954 * equivalence class. And now, just as before, an edge is part of
1955 * a loop iff its two sides are not in the same component.
1957 * This correctly detects even homologically nontrivial loops on a
1958 * torus, because a torus is still _orientable_ - there's no way
1959 * that a loop can join back up with itself with the two sides
1960 * swapped. It would stop working, however, on a Mobius strip or a
1961 * Klein bottle - so if I ever implement either of those modes for
1962 * Net, I'll have to revisit this algorithm yet again and probably
1963 * replace it with a completely general and much more fiddly
1964 * approach such as Tarjan's bridge-finding algorithm (which is
1965 * linear-time, but looks to me as if it's going to take more
1966 * effort to get it working, especially when the graph is
1967 * represented so unlike an ordinary graph).
1969 * In Net, the algorithm as I describe it above has to be fiddled
1970 * with just a little, to deal with the fact that there are two
1971 * kinds of 'vertex' in the graph - one set at face-centres, and
1972 * another set at edge-midpoints where two wires either do or do
1973 * not join. Since those two vertex classes have very different
1974 * representations in the Net data structure, separate code is
1978 /* Four potential edges per grid cell; one dsf node for each side
1979 * of each one makes 8 per cell. */
1980 dsf = snew_dsf(w*h*8);
1982 /* Encode the dsf nodes. We imagine going round anticlockwise, so
1983 * BEFORE(dir) indicates the clockwise side of an edge, e.g. the
1984 * underside of R or the right-hand side of U. AFTER is the other
1986 #define BEFORE(dir) ((dir)==R?7:(dir)==U?1:(dir)==L?3:5)
1987 #define AFTER(dir) ((dir)==R?0:(dir)==U?2:(dir)==L?4:6)
1990 printf("--- begin\n");
1992 for (y = 0; y < h; y++) {
1993 for (x = 0; x < w; x++) {
1994 int tile = tiles[y*w+x];
1996 for (dir = 1; dir < 0x10; dir <<= 1) {
1998 * To unify dsf nodes around a face-centre vertex,
1999 * it's easiest to do it _unconditionally_ - e.g. just
2000 * unify the top side of R with the right side of U
2001 * regardless of whether there's an edge in either
2002 * place. Later we'll also unify the top and bottom
2003 * sides of any nonexistent edge, which will e.g.
2004 * complete a connection BEFORE(U) - AFTER(R) -
2005 * BEFORE(R) - AFTER(D) in the absence of an R edge.
2007 * This is a safe optimisation because these extra dsf
2008 * nodes unified into our equivalence class can't get
2009 * out of control - they are never unified with
2010 * anything _else_ elsewhere in the algorithm.
2013 printf("tile centre %d,%d: merge %d,%d\n",
2015 (y*w+x)*8+AFTER(C(dir)),
2016 (y*w+x)*8+BEFORE(dir));
2019 (y*w+x)*8+AFTER(C(dir)),
2020 (y*w+x)*8+BEFORE(dir));
2025 OFFSETWH(x1, y1, x, y, dir, w, h);
2028 * If the tile does have an edge going out in this
2029 * direction, we must check whether it joins up
2030 * (without being blocked by a barrier) to an edge
2031 * in the next cell along. If so, we unify around
2032 * the edge-centre vertex by joining each side of
2033 * this edge to the appropriate side of the next
2034 * cell's edge; otherwise, the edge is a stub (the
2035 * only one reaching the edge-centre vertex) and
2036 * so we join its own two sides together.
2038 if ((barriers && barriers[y*w+x] & dir) ||
2039 !(tiles[y1*w+x1] & F(dir))) {
2041 printf("tile edge stub %d,%d -> %c: merge %d,%d\n",
2042 x, y, (dir==L?'L':dir==U?'U':dir==R?'R':'D'),
2043 (y*w+x)*8+BEFORE(dir),
2044 (y*w+x)*8+AFTER(dir));
2047 (y*w+x)*8+BEFORE(dir),
2048 (y*w+x)*8+AFTER(dir));
2051 printf("tile edge conn %d,%d -> %c: merge %d,%d\n",
2052 x, y, (dir==L?'L':dir==U?'U':dir==R?'R':'D'),
2053 (y*w+x)*8+BEFORE(dir),
2054 (y*w+x)*8+AFTER(F(dir)));
2057 (y*w+x)*8+BEFORE(dir),
2058 (y1*w+x1)*8+AFTER(F(dir)));
2060 printf("tile edge conn %d,%d -> %c: merge %d,%d\n",
2061 x, y, (dir==L?'L':dir==U?'U':dir==R?'R':'D'),
2062 (y*w+x)*8+AFTER(dir),
2063 (y*w+x)*8+BEFORE(F(dir)));
2066 (y*w+x)*8+AFTER(dir),
2067 (y1*w+x1)*8+BEFORE(F(dir)));
2071 * As discussed above, if this edge doesn't even
2072 * exist, we unify its two sides anyway to
2073 * complete the unification of whatever edges do
2074 * exist in this cell.
2077 printf("tile edge missing %d,%d -> %c: merge %d,%d\n",
2078 x, y, (dir==L?'L':dir==U?'U':dir==R?'R':'D'),
2079 (y*w+x)*8+BEFORE(dir),
2080 (y*w+x)*8+AFTER(dir));
2083 (y*w+x)*8+BEFORE(dir),
2084 (y*w+x)*8+AFTER(dir));
2091 printf("--- end\n");
2093 loops = snewn(w*h, int);
2096 * Now we've done the loop detection and can read off the output
2097 * flags trivially: any piece of connection whose two sides are
2098 * not in the same dsf class is part of a loop.
2100 for (y = 0; y < h; y++) {
2101 for (x = 0; x < w; x++) {
2103 int tile = tiles[y*w+x];
2105 for (dir = 1; dir < 0x10; dir <<= 1) {
2107 (dsf_canonify(dsf, (y*w+x)*8+BEFORE(dir)) !=
2108 dsf_canonify(dsf, (y*w+x)*8+AFTER(dir)))) {
2112 loops[y*w+x] = flags;
2120 static int *compute_loops(const game_state *state)
2122 return compute_loops_inner(state->width, state->height, state->wrapping,
2123 state->tiles, state->barriers);
2127 int org_x, org_y; /* origin */
2128 int cx, cy; /* source tile (game coordinates) */
2131 random_state *rs; /* used for jumbling */
2133 int dragtilex, dragtiley, dragstartx, dragstarty, dragged;
2137 static game_ui *new_ui(const game_state *state)
2141 game_ui *ui = snew(game_ui);
2142 ui->org_x = ui->org_y = 0;
2143 ui->cur_x = ui->cx = state->width / 2;
2144 ui->cur_y = ui->cy = state->height / 2;
2145 ui->cur_visible = FALSE;
2146 get_random_seed(&seed, &seedsize);
2147 ui->rs = random_new(seed, seedsize);
2153 static void free_ui(game_ui *ui)
2155 random_free(ui->rs);
2159 static char *encode_ui(const game_ui *ui)
2163 * We preserve the origin and centre-point coordinates over a
2166 sprintf(buf, "O%d,%d;C%d,%d", ui->org_x, ui->org_y, ui->cx, ui->cy);
2170 static void decode_ui(game_ui *ui, const char *encoding)
2172 sscanf(encoding, "O%d,%d;C%d,%d",
2173 &ui->org_x, &ui->org_y, &ui->cx, &ui->cy);
2176 static void game_changed_state(game_ui *ui, const game_state *oldstate,
2177 const game_state *newstate)
2181 struct game_drawstate {
2189 /* ----------------------------------------------------------------------
2192 static char *interpret_move(const game_state *state, game_ui *ui,
2193 const game_drawstate *ds,
2194 int x, int y, int button)
2197 int tx = -1, ty = -1, dir = 0;
2198 int shift = button & MOD_SHFT, ctrl = button & MOD_CTRL;
2200 NONE, ROTATE_LEFT, ROTATE_180, ROTATE_RIGHT, TOGGLE_LOCK, JUMBLE,
2201 MOVE_ORIGIN, MOVE_SOURCE, MOVE_ORIGIN_AND_SOURCE, MOVE_CURSOR
2204 button &= ~MOD_MASK;
2208 if (button == LEFT_BUTTON ||
2209 button == MIDDLE_BUTTON ||
2211 button == LEFT_DRAG ||
2212 button == LEFT_RELEASE ||
2213 button == RIGHT_DRAG ||
2214 button == RIGHT_RELEASE ||
2216 button == RIGHT_BUTTON) {
2218 if (ui->cur_visible) {
2219 ui->cur_visible = FALSE;
2224 * The button must have been clicked on a valid tile.
2226 x -= WINDOW_OFFSET + TILE_BORDER;
2227 y -= WINDOW_OFFSET + TILE_BORDER;
2232 if (tx >= state->width || ty >= state->height)
2234 /* Transform from physical to game coords */
2235 tx = (tx + ui->org_x) % state->width;
2236 ty = (ty + ui->org_y) % state->height;
2237 if (x % TILE_SIZE >= TILE_SIZE - TILE_BORDER ||
2238 y % TILE_SIZE >= TILE_SIZE - TILE_BORDER)
2243 if (button == MIDDLE_BUTTON
2245 || button == RIGHT_BUTTON /* with a stylus, `right-click' locks */
2249 * Middle button never drags: it only toggles the lock.
2251 action = TOGGLE_LOCK;
2252 } else if (button == LEFT_BUTTON
2253 #ifndef STYLUS_BASED
2254 || button == RIGHT_BUTTON /* (see above) */
2258 * Otherwise, we note down the start point for a drag.
2262 ui->dragstartx = x % TILE_SIZE;
2263 ui->dragstarty = y % TILE_SIZE;
2264 ui->dragged = FALSE;
2265 return nullret; /* no actual action */
2266 } else if (button == LEFT_DRAG
2267 #ifndef STYLUS_BASED
2268 || button == RIGHT_DRAG
2272 * Find the new drag point and see if it necessitates a
2275 int x0,y0, xA,yA, xC,yC, xF,yF;
2277 int d0, dA, dC, dF, dmin;
2282 mx = x - (ui->dragtilex * TILE_SIZE);
2283 my = y - (ui->dragtiley * TILE_SIZE);
2285 x0 = ui->dragstartx;
2286 y0 = ui->dragstarty;
2287 xA = ui->dragstarty;
2288 yA = TILE_SIZE-1 - ui->dragstartx;
2289 xF = TILE_SIZE-1 - ui->dragstartx;
2290 yF = TILE_SIZE-1 - ui->dragstarty;
2291 xC = TILE_SIZE-1 - ui->dragstarty;
2292 yC = ui->dragstartx;
2294 d0 = (mx-x0)*(mx-x0) + (my-y0)*(my-y0);
2295 dA = (mx-xA)*(mx-xA) + (my-yA)*(my-yA);
2296 dF = (mx-xF)*(mx-xF) + (my-yF)*(my-yF);
2297 dC = (mx-xC)*(mx-xC) + (my-yC)*(my-yC);
2299 dmin = min(min(d0,dA),min(dF,dC));
2303 } else if (dF == dmin) {
2304 action = ROTATE_180;
2305 ui->dragstartx = xF;
2306 ui->dragstarty = yF;
2308 } else if (dA == dmin) {
2309 action = ROTATE_LEFT;
2310 ui->dragstartx = xA;
2311 ui->dragstarty = yA;
2313 } else /* dC == dmin */ {
2314 action = ROTATE_RIGHT;
2315 ui->dragstartx = xC;
2316 ui->dragstarty = yC;
2319 } else if (button == LEFT_RELEASE
2320 #ifndef STYLUS_BASED
2321 || button == RIGHT_RELEASE
2326 * There was a click but no perceptible drag:
2327 * revert to single-click behaviour.
2332 if (button == LEFT_RELEASE)
2333 action = ROTATE_LEFT;
2335 action = ROTATE_RIGHT;
2337 return nullret; /* no action */
2340 #else /* USE_DRAGGING */
2342 action = (button == LEFT_BUTTON ? ROTATE_LEFT :
2343 button == RIGHT_BUTTON ? ROTATE_RIGHT : TOGGLE_LOCK);
2345 #endif /* USE_DRAGGING */
2347 } else if (IS_CURSOR_MOVE(button)) {
2349 case CURSOR_UP: dir = U; break;
2350 case CURSOR_DOWN: dir = D; break;
2351 case CURSOR_LEFT: dir = L; break;
2352 case CURSOR_RIGHT: dir = R; break;
2353 default: return nullret;
2355 if (shift && ctrl) action = MOVE_ORIGIN_AND_SOURCE;
2356 else if (shift) action = MOVE_ORIGIN;
2357 else if (ctrl) action = MOVE_SOURCE;
2358 else action = MOVE_CURSOR;
2359 } else if (button == 'a' || button == 's' || button == 'd' ||
2360 button == 'A' || button == 'S' || button == 'D' ||
2361 button == 'f' || button == 'F' ||
2362 IS_CURSOR_SELECT(button)) {
2365 if (button == 'a' || button == 'A' || button == CURSOR_SELECT)
2366 action = ROTATE_LEFT;
2367 else if (button == 's' || button == 'S' || button == CURSOR_SELECT2)
2368 action = TOGGLE_LOCK;
2369 else if (button == 'd' || button == 'D')
2370 action = ROTATE_RIGHT;
2371 else if (button == 'f' || button == 'F')
2372 action = ROTATE_180;
2373 ui->cur_visible = TRUE;
2374 } else if (button == 'j' || button == 'J') {
2375 /* XXX should we have some mouse control for this? */
2381 * The middle button locks or unlocks a tile. (A locked tile
2382 * cannot be turned, and is visually marked as being locked.
2383 * This is a convenience for the player, so that once they are
2384 * sure which way round a tile goes, they can lock it and thus
2385 * avoid forgetting later on that they'd already done that one;
2386 * and the locking also prevents them turning the tile by
2387 * accident. If they change their mind, another middle click
2390 if (action == TOGGLE_LOCK) {
2392 sprintf(buf, "L%d,%d", tx, ty);
2394 } else if (action == ROTATE_LEFT || action == ROTATE_RIGHT ||
2395 action == ROTATE_180) {
2399 * The left and right buttons have no effect if clicked on a
2402 if (tile(state, tx, ty) & LOCKED)
2406 * Otherwise, turn the tile one way or the other. Left button
2407 * turns anticlockwise; right button turns clockwise.
2409 sprintf(buf, "%c%d,%d", (int)(action == ROTATE_LEFT ? 'A' :
2410 action == ROTATE_RIGHT ? 'C' : 'F'), tx, ty);
2412 } else if (action == JUMBLE) {
2414 * Jumble all unlocked tiles to random orientations.
2421 * Maximum string length assumes no int can be converted to
2422 * decimal and take more than 11 digits!
2424 maxlen = state->width * state->height * 25 + 3;
2426 ret = snewn(maxlen, char);
2430 for (jy = 0; jy < state->height; jy++) {
2431 for (jx = 0; jx < state->width; jx++) {
2432 if (!(tile(state, jx, jy) & LOCKED)) {
2433 int rot = random_upto(ui->rs, 4);
2435 p += sprintf(p, ";%c%d,%d", "AFC"[rot-1], jx, jy);
2441 assert(p - ret < maxlen);
2442 ret = sresize(ret, p - ret, char);
2445 } else if (action == MOVE_ORIGIN || action == MOVE_SOURCE ||
2446 action == MOVE_ORIGIN_AND_SOURCE || action == MOVE_CURSOR) {
2448 if (action == MOVE_ORIGIN || action == MOVE_ORIGIN_AND_SOURCE) {
2449 if (state->wrapping) {
2450 OFFSET(ui->org_x, ui->org_y, ui->org_x, ui->org_y, dir, state);
2451 } else return nullret; /* disallowed for non-wrapping grids */
2453 if (action == MOVE_SOURCE || action == MOVE_ORIGIN_AND_SOURCE) {
2454 OFFSET(ui->cx, ui->cy, ui->cx, ui->cy, dir, state);
2456 if (action == MOVE_CURSOR) {
2457 OFFSET(ui->cur_x, ui->cur_y, ui->cur_x, ui->cur_y, dir, state);
2458 ui->cur_visible = TRUE;
2466 static game_state *execute_move(const game_state *from, const char *move)
2469 int tx = -1, ty = -1, n, noanim, orig;
2471 ret = dup_game(from);
2473 if (move[0] == 'J' || move[0] == 'S') {
2475 ret->used_solve = TRUE;
2484 ret->last_rotate_dir = 0; /* suppress animation */
2485 ret->last_rotate_x = ret->last_rotate_y = 0;
2488 if ((move[0] == 'A' || move[0] == 'C' ||
2489 move[0] == 'F' || move[0] == 'L') &&
2490 sscanf(move+1, "%d,%d%n", &tx, &ty, &n) >= 2 &&
2491 tx >= 0 && tx < from->width && ty >= 0 && ty < from->height) {
2492 orig = tile(ret, tx, ty);
2493 if (move[0] == 'A') {
2494 tile(ret, tx, ty) = A(orig);
2496 ret->last_rotate_dir = +1;
2497 } else if (move[0] == 'F') {
2498 tile(ret, tx, ty) = F(orig);
2500 ret->last_rotate_dir = +2; /* + for sake of argument */
2501 } else if (move[0] == 'C') {
2502 tile(ret, tx, ty) = C(orig);
2504 ret->last_rotate_dir = -1;
2506 assert(move[0] == 'L');
2507 tile(ret, tx, ty) ^= LOCKED;
2511 if (*move == ';') move++;
2518 if (tx == -1 || ty == -1) { free_game(ret); return NULL; }
2519 ret->last_rotate_x = tx;
2520 ret->last_rotate_y = ty;
2524 * Check whether the game has been completed.
2526 * For this purpose it doesn't matter where the source square
2527 * is, because we can start from anywhere and correctly
2528 * determine whether the game is completed.
2531 unsigned char *active = compute_active(ret, 0, 0);
2533 int complete = TRUE;
2535 for (x1 = 0; x1 < ret->width; x1++)
2536 for (y1 = 0; y1 < ret->height; y1++)
2537 if ((tile(ret, x1, y1) & 0xF) && !index(ret, active, x1, y1)) {
2539 goto break_label; /* break out of two loops at once */
2546 ret->completed = TRUE;
2553 /* ----------------------------------------------------------------------
2554 * Routines for drawing the game position on the screen.
2557 static game_drawstate *game_new_drawstate(drawing *dr, const game_state *state)
2559 game_drawstate *ds = snew(game_drawstate);
2562 ds->started = FALSE;
2563 ds->width = state->width;
2564 ds->height = state->height;
2565 ds->org_x = ds->org_y = -1;
2566 ds->visible = snewn(state->width * state->height, int);
2567 ds->tilesize = 0; /* undecided yet */
2568 for (i = 0; i < state->width * state->height; i++)
2569 ds->visible[i] = -1;
2574 static void game_free_drawstate(drawing *dr, game_drawstate *ds)
2580 static void game_compute_size(const game_params *params, int tilesize,
2583 *x = WINDOW_OFFSET * 2 + tilesize * params->width + TILE_BORDER;
2584 *y = WINDOW_OFFSET * 2 + tilesize * params->height + TILE_BORDER;
2587 static void game_set_size(drawing *dr, game_drawstate *ds,
2588 const game_params *params, int tilesize)
2590 ds->tilesize = tilesize;
2593 static float *game_colours(frontend *fe, int *ncolours)
2597 ret = snewn(NCOLOURS * 3, float);
2598 *ncolours = NCOLOURS;
2601 * Basic background colour is whatever the front end thinks is
2602 * a sensible default.
2604 frontend_default_colour(fe, &ret[COL_BACKGROUND * 3]);
2609 ret[COL_WIRE * 3 + 0] = 0.0F;
2610 ret[COL_WIRE * 3 + 1] = 0.0F;
2611 ret[COL_WIRE * 3 + 2] = 0.0F;
2614 * Powered wires and powered endpoints are cyan.
2616 ret[COL_POWERED * 3 + 0] = 0.0F;
2617 ret[COL_POWERED * 3 + 1] = 1.0F;
2618 ret[COL_POWERED * 3 + 2] = 1.0F;
2623 ret[COL_BARRIER * 3 + 0] = 1.0F;
2624 ret[COL_BARRIER * 3 + 1] = 0.0F;
2625 ret[COL_BARRIER * 3 + 2] = 0.0F;
2628 * Highlighted loops are red as well.
2630 ret[COL_LOOP * 3 + 0] = 1.0F;
2631 ret[COL_LOOP * 3 + 1] = 0.0F;
2632 ret[COL_LOOP * 3 + 2] = 0.0F;
2635 * Unpowered endpoints are blue.
2637 ret[COL_ENDPOINT * 3 + 0] = 0.0F;
2638 ret[COL_ENDPOINT * 3 + 1] = 0.0F;
2639 ret[COL_ENDPOINT * 3 + 2] = 1.0F;
2642 * Tile borders are a darker grey than the background.
2644 ret[COL_BORDER * 3 + 0] = 0.5F * ret[COL_BACKGROUND * 3 + 0];
2645 ret[COL_BORDER * 3 + 1] = 0.5F * ret[COL_BACKGROUND * 3 + 1];
2646 ret[COL_BORDER * 3 + 2] = 0.5F * ret[COL_BACKGROUND * 3 + 2];
2649 * Locked tiles are a grey in between those two.
2651 ret[COL_LOCKED * 3 + 0] = 0.75F * ret[COL_BACKGROUND * 3 + 0];
2652 ret[COL_LOCKED * 3 + 1] = 0.75F * ret[COL_BACKGROUND * 3 + 1];
2653 ret[COL_LOCKED * 3 + 2] = 0.75F * ret[COL_BACKGROUND * 3 + 2];
2658 static void draw_filled_line(drawing *dr, int x1, int y1, int x2, int y2,
2661 draw_line(dr, x1-1, y1, x2-1, y2, COL_WIRE);
2662 draw_line(dr, x1+1, y1, x2+1, y2, COL_WIRE);
2663 draw_line(dr, x1, y1-1, x2, y2-1, COL_WIRE);
2664 draw_line(dr, x1, y1+1, x2, y2+1, COL_WIRE);
2665 draw_line(dr, x1, y1, x2, y2, colour);
2668 static void draw_rect_coords(drawing *dr, int x1, int y1, int x2, int y2,
2671 int mx = (x1 < x2 ? x1 : x2);
2672 int my = (y1 < y2 ? y1 : y2);
2673 int dx = (x2 + x1 - 2*mx + 1);
2674 int dy = (y2 + y1 - 2*my + 1);
2676 draw_rect(dr, mx, my, dx, dy, colour);
2680 * draw_barrier_corner() and draw_barrier() are passed physical coords
2682 static void draw_barrier_corner(drawing *dr, game_drawstate *ds,
2683 int x, int y, int dx, int dy, int phase)
2685 int bx = WINDOW_OFFSET + TILE_SIZE * x;
2686 int by = WINDOW_OFFSET + TILE_SIZE * y;
2689 x1 = (dx > 0 ? TILE_SIZE+TILE_BORDER-1 : 0);
2690 y1 = (dy > 0 ? TILE_SIZE+TILE_BORDER-1 : 0);
2693 draw_rect_coords(dr, bx+x1+dx, by+y1,
2694 bx+x1-TILE_BORDER*dx, by+y1-(TILE_BORDER-1)*dy,
2696 draw_rect_coords(dr, bx+x1, by+y1+dy,
2697 bx+x1-(TILE_BORDER-1)*dx, by+y1-TILE_BORDER*dy,
2700 draw_rect_coords(dr, bx+x1, by+y1,
2701 bx+x1-(TILE_BORDER-1)*dx, by+y1-(TILE_BORDER-1)*dy,
2706 static void draw_barrier(drawing *dr, game_drawstate *ds,
2707 int x, int y, int dir, int phase)
2709 int bx = WINDOW_OFFSET + TILE_SIZE * x;
2710 int by = WINDOW_OFFSET + TILE_SIZE * y;
2713 x1 = (X(dir) > 0 ? TILE_SIZE : X(dir) == 0 ? TILE_BORDER : 0);
2714 y1 = (Y(dir) > 0 ? TILE_SIZE : Y(dir) == 0 ? TILE_BORDER : 0);
2715 w = (X(dir) ? TILE_BORDER : TILE_SIZE - TILE_BORDER);
2716 h = (Y(dir) ? TILE_BORDER : TILE_SIZE - TILE_BORDER);
2719 draw_rect(dr, bx+x1-X(dir), by+y1-Y(dir), w, h, COL_WIRE);
2721 draw_rect(dr, bx+x1, by+y1, w, h, COL_BARRIER);
2726 * draw_tile() is passed physical coordinates
2728 static void draw_tile(drawing *dr, const game_state *state, game_drawstate *ds,
2729 int x, int y, int tile, int src, float angle, int cursor)
2731 int bx = WINDOW_OFFSET + TILE_SIZE * x;
2732 int by = WINDOW_OFFSET + TILE_SIZE * y;
2734 float cx, cy, ex, ey, tx, ty;
2735 int dir, col, phase;
2738 * When we draw a single tile, we must draw everything up to
2739 * and including the borders around the tile. This means that
2740 * if the neighbouring tiles have connections to those borders,
2741 * we must draw those connections on the borders themselves.
2744 clip(dr, bx, by, TILE_SIZE+TILE_BORDER, TILE_SIZE+TILE_BORDER);
2747 * So. First blank the tile out completely: draw a big
2748 * rectangle in border colour, and a smaller rectangle in
2749 * background colour to fill it in.
2751 draw_rect(dr, bx, by, TILE_SIZE+TILE_BORDER, TILE_SIZE+TILE_BORDER,
2753 draw_rect(dr, bx+TILE_BORDER, by+TILE_BORDER,
2754 TILE_SIZE-TILE_BORDER, TILE_SIZE-TILE_BORDER,
2755 tile & LOCKED ? COL_LOCKED : COL_BACKGROUND);
2758 * Draw an inset outline rectangle as a cursor, in whichever of
2759 * COL_LOCKED and COL_BACKGROUND we aren't currently drawing
2763 draw_line(dr, bx+TILE_SIZE/8, by+TILE_SIZE/8,
2764 bx+TILE_SIZE/8, by+TILE_SIZE-TILE_SIZE/8,
2765 tile & LOCKED ? COL_BACKGROUND : COL_LOCKED);
2766 draw_line(dr, bx+TILE_SIZE/8, by+TILE_SIZE/8,
2767 bx+TILE_SIZE-TILE_SIZE/8, by+TILE_SIZE/8,
2768 tile & LOCKED ? COL_BACKGROUND : COL_LOCKED);
2769 draw_line(dr, bx+TILE_SIZE-TILE_SIZE/8, by+TILE_SIZE/8,
2770 bx+TILE_SIZE-TILE_SIZE/8, by+TILE_SIZE-TILE_SIZE/8,
2771 tile & LOCKED ? COL_BACKGROUND : COL_LOCKED);
2772 draw_line(dr, bx+TILE_SIZE/8, by+TILE_SIZE-TILE_SIZE/8,
2773 bx+TILE_SIZE-TILE_SIZE/8, by+TILE_SIZE-TILE_SIZE/8,
2774 tile & LOCKED ? COL_BACKGROUND : COL_LOCKED);
2778 * Set up the rotation matrix.
2780 matrix[0] = (float)cos(angle * PI / 180.0);
2781 matrix[1] = (float)-sin(angle * PI / 180.0);
2782 matrix[2] = (float)sin(angle * PI / 180.0);
2783 matrix[3] = (float)cos(angle * PI / 180.0);
2788 cx = cy = TILE_BORDER + (TILE_SIZE-TILE_BORDER) / 2.0F - 0.5F;
2789 col = (tile & ACTIVE ? COL_POWERED : COL_WIRE);
2790 for (dir = 1; dir < 0x10; dir <<= 1) {
2792 ex = (TILE_SIZE - TILE_BORDER - 1.0F) / 2.0F * X(dir);
2793 ey = (TILE_SIZE - TILE_BORDER - 1.0F) / 2.0F * Y(dir);
2794 MATMUL(tx, ty, matrix, ex, ey);
2795 draw_filled_line(dr, bx+(int)cx, by+(int)cy,
2796 bx+(int)(cx+tx), by+(int)(cy+ty),
2800 for (dir = 1; dir < 0x10; dir <<= 1) {
2802 ex = (TILE_SIZE - TILE_BORDER - 1.0F) / 2.0F * X(dir);
2803 ey = (TILE_SIZE - TILE_BORDER - 1.0F) / 2.0F * Y(dir);
2804 MATMUL(tx, ty, matrix, ex, ey);
2805 draw_line(dr, bx+(int)cx, by+(int)cy,
2806 bx+(int)(cx+tx), by+(int)(cy+ty),
2807 (tile & LOOP(dir)) ? COL_LOOP : col);
2810 /* If we've drawn any loop-highlighted arms, make sure the centre
2811 * point is loop-coloured rather than a later arm overwriting it. */
2812 if (tile & (RLOOP | ULOOP | LLOOP | DLOOP))
2813 draw_rect(dr, bx+(int)cx, by+(int)cy, 1, 1, COL_LOOP);
2816 * Draw the box in the middle. We do this in blue if the tile
2817 * is an unpowered endpoint, in cyan if the tile is a powered
2818 * endpoint, in black if the tile is the centrepiece, and
2819 * otherwise not at all.
2824 else if (COUNT(tile) == 1) {
2825 col = (tile & ACTIVE ? COL_POWERED : COL_ENDPOINT);
2830 points[0] = +1; points[1] = +1;
2831 points[2] = +1; points[3] = -1;
2832 points[4] = -1; points[5] = -1;
2833 points[6] = -1; points[7] = +1;
2835 for (i = 0; i < 8; i += 2) {
2836 ex = (TILE_SIZE * 0.24F) * points[i];
2837 ey = (TILE_SIZE * 0.24F) * points[i+1];
2838 MATMUL(tx, ty, matrix, ex, ey);
2839 points[i] = bx+(int)(cx+tx);
2840 points[i+1] = by+(int)(cy+ty);
2843 draw_polygon(dr, points, 4, col, COL_WIRE);
2847 * Draw the points on the border if other tiles are connected
2850 for (dir = 1; dir < 0x10; dir <<= 1) {
2851 int dx, dy, px, py, lx, ly, vx, vy, ox, oy;
2859 if (ox < 0 || ox >= state->width || oy < 0 || oy >= state->height)
2862 if (!(tile(state, GX(ox), GY(oy)) & F(dir)))
2865 px = bx + (int)(dx>0 ? TILE_SIZE + TILE_BORDER - 1 : dx<0 ? 0 : cx);
2866 py = by + (int)(dy>0 ? TILE_SIZE + TILE_BORDER - 1 : dy<0 ? 0 : cy);
2867 lx = dx * (TILE_BORDER-1);
2868 ly = dy * (TILE_BORDER-1);
2872 if (angle == 0.0 && (tile & dir)) {
2874 * If we are fully connected to the other tile, we must
2875 * draw right across the tile border. (We can use our
2876 * own ACTIVE state to determine what colour to do this
2877 * in: if we are fully connected to the other tile then
2878 * the two ACTIVE states will be the same.)
2880 draw_rect_coords(dr, px-vx, py-vy, px+lx+vx, py+ly+vy, COL_WIRE);
2881 draw_rect_coords(dr, px, py, px+lx, py+ly,
2882 ((tile & LOOP(dir)) ? COL_LOOP :
2883 (tile & ACTIVE) ? COL_POWERED :
2887 * The other tile extends into our border, but isn't
2888 * actually connected to us. Just draw a single black
2891 draw_rect_coords(dr, px, py, px, py, COL_WIRE);
2896 * Draw barrier corners, and then barriers.
2898 for (phase = 0; phase < 2; phase++) {
2899 for (dir = 1; dir < 0x10; dir <<= 1) {
2900 int x1, y1, corner = FALSE;
2902 * If at least one barrier terminates at the corner
2903 * between dir and A(dir), draw a barrier corner.
2905 if (barrier(state, GX(x), GY(y)) & (dir | A(dir))) {
2909 * Only count barriers terminating at this corner
2910 * if they're physically next to the corner. (That
2911 * is, if they've wrapped round from the far side
2912 * of the screen, they don't count.)
2916 if (x1 >= 0 && x1 < state->width &&
2917 y1 >= 0 && y1 < state->height &&
2918 (barrier(state, GX(x1), GY(y1)) & A(dir))) {
2923 if (x1 >= 0 && x1 < state->width &&
2924 y1 >= 0 && y1 < state->height &&
2925 (barrier(state, GX(x1), GY(y1)) & dir))
2932 * At least one barrier terminates here. Draw a
2935 draw_barrier_corner(dr, ds, x, y,
2936 X(dir)+X(A(dir)), Y(dir)+Y(A(dir)),
2941 for (dir = 1; dir < 0x10; dir <<= 1)
2942 if (barrier(state, GX(x), GY(y)) & dir)
2943 draw_barrier(dr, ds, x, y, dir, phase);
2948 draw_update(dr, bx, by, TILE_SIZE+TILE_BORDER, TILE_SIZE+TILE_BORDER);
2951 static void game_redraw(drawing *dr, game_drawstate *ds,
2952 const game_state *oldstate, const game_state *state,
2953 int dir, const game_ui *ui,
2956 int x, y, tx, ty, frame, last_rotate_dir, moved_origin = FALSE;
2957 unsigned char *active;
2962 * Clear the screen, and draw the exterior barrier lines, if
2963 * this is our first call or if the origin has changed.
2965 if (!ds->started || ui->org_x != ds->org_x || ui->org_y != ds->org_y) {
2971 WINDOW_OFFSET * 2 + TILE_SIZE * state->width + TILE_BORDER,
2972 WINDOW_OFFSET * 2 + TILE_SIZE * state->height + TILE_BORDER,
2975 ds->org_x = ui->org_x;
2976 ds->org_y = ui->org_y;
2977 moved_origin = TRUE;
2979 draw_update(dr, 0, 0,
2980 WINDOW_OFFSET*2 + TILE_SIZE*state->width + TILE_BORDER,
2981 WINDOW_OFFSET*2 + TILE_SIZE*state->height + TILE_BORDER);
2983 for (phase = 0; phase < 2; phase++) {
2985 for (x = 0; x < ds->width; x++) {
2986 if (x+1 < ds->width) {
2987 if (barrier(state, GX(x), GY(0)) & R)
2988 draw_barrier_corner(dr, ds, x, -1, +1, +1, phase);
2989 if (barrier(state, GX(x), GY(ds->height-1)) & R)
2990 draw_barrier_corner(dr, ds, x, ds->height, +1, -1, phase);
2992 if (barrier(state, GX(x), GY(0)) & U) {
2993 draw_barrier_corner(dr, ds, x, -1, -1, +1, phase);
2994 draw_barrier_corner(dr, ds, x, -1, +1, +1, phase);
2995 draw_barrier(dr, ds, x, -1, D, phase);
2997 if (barrier(state, GX(x), GY(ds->height-1)) & D) {
2998 draw_barrier_corner(dr, ds, x, ds->height, -1, -1, phase);
2999 draw_barrier_corner(dr, ds, x, ds->height, +1, -1, phase);
3000 draw_barrier(dr, ds, x, ds->height, U, phase);
3004 for (y = 0; y < ds->height; y++) {
3005 if (y+1 < ds->height) {
3006 if (barrier(state, GX(0), GY(y)) & D)
3007 draw_barrier_corner(dr, ds, -1, y, +1, +1, phase);
3008 if (barrier(state, GX(ds->width-1), GY(y)) & D)
3009 draw_barrier_corner(dr, ds, ds->width, y, -1, +1, phase);
3011 if (barrier(state, GX(0), GY(y)) & L) {
3012 draw_barrier_corner(dr, ds, -1, y, +1, -1, phase);
3013 draw_barrier_corner(dr, ds, -1, y, +1, +1, phase);
3014 draw_barrier(dr, ds, -1, y, R, phase);
3016 if (barrier(state, GX(ds->width-1), GY(y)) & R) {
3017 draw_barrier_corner(dr, ds, ds->width, y, -1, -1, phase);
3018 draw_barrier_corner(dr, ds, ds->width, y, -1, +1, phase);
3019 draw_barrier(dr, ds, ds->width, y, L, phase);
3026 last_rotate_dir = dir==-1 ? oldstate->last_rotate_dir :
3027 state->last_rotate_dir;
3028 if (oldstate && (t < ROTATE_TIME) && last_rotate_dir) {
3030 * We're animating a single tile rotation. Find the turning
3033 tx = (dir==-1 ? oldstate->last_rotate_x : state->last_rotate_x);
3034 ty = (dir==-1 ? oldstate->last_rotate_y : state->last_rotate_y);
3035 angle = last_rotate_dir * dir * 90.0F * (t / ROTATE_TIME);
3042 * We're animating a completion flash. Find which frame
3045 frame = (int)(ft / FLASH_FRAME);
3049 * Draw any tile which differs from the way it was last drawn.
3051 active = compute_active(state, ui->cx, ui->cy);
3052 loops = compute_loops(state);
3054 for (x = 0; x < ds->width; x++)
3055 for (y = 0; y < ds->height; y++) {
3056 int c = tile(state, GX(x), GY(y)) |
3057 index(state, active, GX(x), GY(y)) |
3058 index(state, loops, GX(x), GY(y));
3059 int is_src = GX(x) == ui->cx && GY(y) == ui->cy;
3060 int is_anim = GX(x) == tx && GY(y) == ty;
3061 int is_cursor = ui->cur_visible &&
3062 GX(x) == ui->cur_x && GY(y) == ui->cur_y;
3065 * In a completion flash, we adjust the LOCKED bit
3066 * depending on our distance from the centre point and
3070 int rcx = RX(ui->cx), rcy = RY(ui->cy);
3071 int xdist, ydist, dist;
3072 xdist = (x < rcx ? rcx - x : x - rcx);
3073 ydist = (y < rcy ? rcy - y : y - rcy);
3074 dist = (xdist > ydist ? xdist : ydist);
3076 if (frame >= dist && frame < dist+4) {
3077 int lock = (frame - dist) & 1;
3078 lock = lock ? LOCKED : 0;
3079 c = (c &~ LOCKED) | lock;
3084 index(state, ds->visible, x, y) != c ||
3085 index(state, ds->visible, x, y) == -1 ||
3086 is_src || is_anim || is_cursor) {
3087 draw_tile(dr, state, ds, x, y, c,
3088 is_src, (is_anim ? angle : 0.0F), is_cursor);
3089 if (is_src || is_anim || is_cursor)
3090 index(state, ds->visible, x, y) = -1;
3092 index(state, ds->visible, x, y) = c;
3097 * Update the status bar.
3100 char statusbuf[256];
3103 n = state->width * state->height;
3104 for (i = a = n2 = 0; i < n; i++) {
3107 if (state->tiles[i] & 0xF)
3111 sprintf(statusbuf, "%sActive: %d/%d",
3112 (state->used_solve ? "Auto-solved. " :
3113 state->completed ? "COMPLETED! " : ""), a, n2);
3115 status_bar(dr, statusbuf);
3122 static float game_anim_length(const game_state *oldstate,
3123 const game_state *newstate, int dir, game_ui *ui)
3125 int last_rotate_dir;
3128 * Don't animate if last_rotate_dir is zero.
3130 last_rotate_dir = dir==-1 ? oldstate->last_rotate_dir :
3131 newstate->last_rotate_dir;
3132 if (last_rotate_dir)
3138 static float game_flash_length(const game_state *oldstate,
3139 const game_state *newstate, int dir, game_ui *ui)
3142 * If the game has just been completed, we display a completion
3145 if (!oldstate->completed && newstate->completed &&
3146 !oldstate->used_solve && !newstate->used_solve) {
3148 if (size < newstate->width)
3149 size = newstate->width;
3150 if (size < newstate->height)
3151 size = newstate->height;
3152 return FLASH_FRAME * (size+4);
3158 static int game_status(const game_state *state)
3160 return state->completed ? +1 : 0;
3163 static int game_timing_state(const game_state *state, game_ui *ui)
3168 static void game_print_size(const game_params *params, float *x, float *y)
3173 * I'll use 8mm squares by default.
3175 game_compute_size(params, 800, &pw, &ph);
3180 static void draw_diagram(drawing *dr, game_drawstate *ds, int x, int y,
3181 int topleft, int v, int drawlines, int ink)
3183 int tx, ty, cx, cy, r, br, k, thick;
3185 tx = WINDOW_OFFSET + TILE_SIZE * x;
3186 ty = WINDOW_OFFSET + TILE_SIZE * y;
3189 * Find our centre point.
3192 cx = tx + (v & L ? TILE_SIZE / 4 : TILE_SIZE / 6);
3193 cy = ty + (v & U ? TILE_SIZE / 4 : TILE_SIZE / 6);
3195 br = TILE_SIZE / 32;
3197 cx = tx + TILE_SIZE / 2;
3198 cy = ty + TILE_SIZE / 2;
3205 * Draw the square block if we have an endpoint.
3207 if (v == 1 || v == 2 || v == 4 || v == 8)
3208 draw_rect(dr, cx - br, cy - br, br*2, br*2, ink);
3211 * Draw each radial line.
3214 for (k = 1; k < 16; k *= 2)
3216 int x1 = min(cx, cx + (r-thick) * X(k));
3217 int x2 = max(cx, cx + (r-thick) * X(k));
3218 int y1 = min(cy, cy + (r-thick) * Y(k));
3219 int y2 = max(cy, cy + (r-thick) * Y(k));
3220 draw_rect(dr, x1 - thick, y1 - thick,
3221 (x2 - x1) + 2*thick, (y2 - y1) + 2*thick, ink);
3226 static void game_print(drawing *dr, const game_state *state, int tilesize)
3228 int w = state->width, h = state->height;
3229 int ink = print_mono_colour(dr, 0);
3232 /* Ick: fake up `ds->tilesize' for macro expansion purposes */
3233 game_drawstate ads, *ds = &ads;
3234 game_set_size(dr, ds, NULL, tilesize);
3239 print_line_width(dr, TILE_SIZE / (state->wrapping ? 128 : 12));
3240 draw_rect_outline(dr, WINDOW_OFFSET, WINDOW_OFFSET,
3241 TILE_SIZE * w, TILE_SIZE * h, ink);
3246 print_line_width(dr, TILE_SIZE / 128);
3247 for (x = 1; x < w; x++)
3248 draw_line(dr, WINDOW_OFFSET + TILE_SIZE * x, WINDOW_OFFSET,
3249 WINDOW_OFFSET + TILE_SIZE * x, WINDOW_OFFSET + TILE_SIZE * h,
3251 for (y = 1; y < h; y++)
3252 draw_line(dr, WINDOW_OFFSET, WINDOW_OFFSET + TILE_SIZE * y,
3253 WINDOW_OFFSET + TILE_SIZE * w, WINDOW_OFFSET + TILE_SIZE * y,
3259 for (y = 0; y <= h; y++)
3260 for (x = 0; x <= w; x++) {
3261 int b = barrier(state, x % w, y % h);
3262 if (x < w && (b & U))
3263 draw_rect(dr, WINDOW_OFFSET + TILE_SIZE * x - TILE_SIZE/24,
3264 WINDOW_OFFSET + TILE_SIZE * y - TILE_SIZE/24,
3265 TILE_SIZE + TILE_SIZE/24 * 2, TILE_SIZE/24 * 2, ink);
3266 if (y < h && (b & L))
3267 draw_rect(dr, WINDOW_OFFSET + TILE_SIZE * x - TILE_SIZE/24,
3268 WINDOW_OFFSET + TILE_SIZE * y - TILE_SIZE/24,
3269 TILE_SIZE/24 * 2, TILE_SIZE + TILE_SIZE/24 * 2, ink);
3275 for (y = 0; y < h; y++)
3276 for (x = 0; x < w; x++) {
3277 int vx, v = tile(state, x, y);
3278 int locked = v & LOCKED;
3283 * Rotate into a standard orientation for the top left
3287 while (vx != 0 && vx != 15 && vx != 1 && vx != 9 && vx != 13 &&
3292 * Draw the top left corner diagram.
3294 draw_diagram(dr, ds, x, y, TRUE, vx, TRUE, ink);
3297 * Draw the real solution diagram, if we're doing so.
3299 draw_diagram(dr, ds, x, y, FALSE, v, locked, ink);
3307 const struct game thegame = {
3308 "Net", "games.net", "net",
3315 TRUE, game_configure, custom_params,
3323 FALSE, game_can_format_as_text_now, game_text_format,
3331 PREFERRED_TILE_SIZE, game_compute_size, game_set_size,
3334 game_free_drawstate,
3339 TRUE, FALSE, game_print_size, game_print,
3340 TRUE, /* wants_statusbar */
3341 FALSE, game_timing_state,