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1/*
2 * net.c: Net game.
3 */
4
5#include <stdio.h>
6#include <stdlib.h>
7#include <string.h>
8#include <assert.h>
9#include <ctype.h>
10#include <math.h>
11
12#include "puzzles.h"
13#include "tree234.h"
14
15/*
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.
25 */
26#ifdef STYLUS_BASED
27#define USE_DRAGGING
28#endif
29
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; \
35} while (0)
36
37/* Direction and other bitfields */
38#define R 0x01
39#define U 0x02
40#define L 0x04
41#define D 0x08
42#define LOCKED 0x10
43#define ACTIVE 0x20
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)
49
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) )
57
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 )
61
62/* Bit count */
63#define COUNT(x) ( (((x) & 0x08) >> 3) + (((x) & 0x04) >> 2) + \
64 (((x) & 0x02) >> 1) + ((x) & 0x01) )
65
66#define PREFERRED_TILE_SIZE 32
67#define TILE_SIZE (ds->tilesize)
68#define TILE_BORDER 1
69#ifdef SMALL_SCREEN
70#define WINDOW_OFFSET 4
71#else
72#define WINDOW_OFFSET 16
73#endif
74
75#define ROTATE_TIME 0.13F
76#define FLASH_FRAME 0.07F
77
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)
84
85enum {
86 COL_BACKGROUND,
87 COL_LOCKED,
88 COL_BORDER,
89 COL_WIRE,
90 COL_ENDPOINT,
91 COL_POWERED,
92 COL_BARRIER,
93 COL_LOOP,
94 NCOLOURS
95};
96
97struct game_params {
98 int width;
99 int height;
100 int wrapping;
101 int unique;
102 float barrier_probability;
103};
104
105struct game_state {
106 int width, height, wrapping, completed;
107 int last_rotate_x, last_rotate_y, last_rotate_dir;
108 int used_solve;
109 unsigned char *tiles;
110 unsigned char *barriers;
111};
112
113#define OFFSETWH(x2,y2,x1,y1,dir,width,height) \
114 ( (x2) = ((x1) + width + X((dir))) % width, \
115 (y2) = ((y1) + height + Y((dir))) % height)
116
117#define OFFSET(x2,y2,x1,y1,dir,state) \
118 OFFSETWH(x2,y2,x1,y1,dir,(state)->width,(state)->height)
119
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)
123
124struct xyd {
125 int x, y, direction;
126};
127
128static 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;
131 if (a->x < b->x)
132 return -1;
133 if (a->x > b->x)
134 return +1;
135 if (a->y < b->y)
136 return -1;
137 if (a->y > b->y)
138 return +1;
139 if (a->direction < b->direction)
140 return -1;
141 if (a->direction > b->direction)
142 return +1;
143 return 0;
144}
145
146static int xyd_cmp_nc(void *av, void *bv) { return xyd_cmp(av, bv); }
147
148static struct xyd *new_xyd(int x, int y, int direction)
149{
150 struct xyd *xyd = snew(struct xyd);
151 xyd->x = x;
152 xyd->y = y;
153 xyd->direction = direction;
154 return xyd;
155}
156
157/* ----------------------------------------------------------------------
158 * Manage game parameters.
159 */
160static game_params *default_params(void)
161{
162 game_params *ret = snew(game_params);
163
164 ret->width = 5;
165 ret->height = 5;
166 ret->wrapping = FALSE;
167 ret->unique = TRUE;
168 ret->barrier_probability = 0.0;
169
170 return ret;
171}
172
173static 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},
178#ifndef SMALL_SCREEN
179 {13, 11, FALSE, TRUE, 0.0},
180#endif
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},
185#ifndef SMALL_SCREEN
186 {13, 11, TRUE, TRUE, 0.0},
187#endif
188};
189
190static int game_fetch_preset(int i, char **name, game_params **params)
191{
192 game_params *ret;
193 char str[80];
194
195 if (i < 0 || i >= lenof(net_presets))
196 return FALSE;
197
198 ret = snew(game_params);
199 *ret = net_presets[i];
200
201 sprintf(str, "%dx%d%s", ret->width, ret->height,
202 ret->wrapping ? " wrapping" : "");
203
204 *name = dupstr(str);
205 *params = ret;
206 return TRUE;
207}
208
209static void free_params(game_params *params)
210{
211 sfree(params);
212}
213
214static game_params *dup_params(const game_params *params)
215{
216 game_params *ret = snew(game_params);
217 *ret = *params; /* structure copy */
218 return ret;
219}
220
221static void decode_params(game_params *ret, char const *string)
222{
223 char const *p = string;
224
225 ret->width = atoi(p);
226 while (*p && isdigit((unsigned char)*p)) p++;
227 if (*p == 'x') {
228 p++;
229 ret->height = atoi(p);
230 while (*p && isdigit((unsigned char)*p)) p++;
231 } else {
232 ret->height = ret->width;
233 }
234
235 while (*p) {
236 if (*p == 'w') {
237 p++;
238 ret->wrapping = TRUE;
239 } else if (*p == 'b') {
240 p++;
241 ret->barrier_probability = (float)atof(p);
242 while (*p && (*p == '.' || isdigit((unsigned char)*p))) p++;
243 } else if (*p == 'a') {
244 p++;
245 ret->unique = FALSE;
246 } else
247 p++; /* skip any other gunk */
248 }
249}
250
251static char *encode_params(const game_params *params, int full)
252{
253 char ret[400];
254 int len;
255
256 len = sprintf(ret, "%dx%d", params->width, params->height);
257 if (params->wrapping)
258 ret[len++] = 'w';
259 if (full && params->barrier_probability)
260 len += sprintf(ret+len, "b%g", params->barrier_probability);
261 if (full && !params->unique)
262 ret[len++] = 'a';
263 assert(len < lenof(ret));
264 ret[len] = '\0';
265
266 return dupstr(ret);
267}
268
269static config_item *game_configure(const game_params *params)
270{
271 config_item *ret;
272 char buf[80];
273
274 ret = snewn(6, config_item);
275
276 ret[0].name = "Width";
277 ret[0].type = C_STRING;
278 sprintf(buf, "%d", params->width);
279 ret[0].sval = dupstr(buf);
280 ret[0].ival = 0;
281
282 ret[1].name = "Height";
283 ret[1].type = C_STRING;
284 sprintf(buf, "%d", params->height);
285 ret[1].sval = dupstr(buf);
286 ret[1].ival = 0;
287
288 ret[2].name = "Walls wrap around";
289 ret[2].type = C_BOOLEAN;
290 ret[2].sval = NULL;
291 ret[2].ival = params->wrapping;
292
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);
297 ret[3].ival = 0;
298
299 ret[4].name = "Ensure unique solution";
300 ret[4].type = C_BOOLEAN;
301 ret[4].sval = NULL;
302 ret[4].ival = params->unique;
303
304 ret[5].name = NULL;
305 ret[5].type = C_END;
306 ret[5].sval = NULL;
307 ret[5].ival = 0;
308
309 return ret;
310}
311
312static game_params *custom_params(const config_item *cfg)
313{
314 game_params *ret = snew(game_params);
315
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;
321
322 return ret;
323}
324
325static char *validate_params(const game_params *params, int full)
326{
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";
335
336 /*
337 * Specifying either grid dimension as 2 in a wrapping puzzle
338 * makes it actually impossible to ensure a unique puzzle
339 * solution.
340 *
341 * Proof:
342 *
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.)
347 *
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).
351 *
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
354 * is connected.
355 *
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. []
363 *
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.
372 *
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. []
378 */
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";
383
384 return NULL;
385}
386
387/* ----------------------------------------------------------------------
388 * Solver used to assure solution uniqueness during generation.
389 */
390
391/*
392 * Test cases I used while debugging all this were
393 *
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.
398 *
399 * An even better one is
400 * 13x11w#507896411361192
401 * which expands to
402 * 13x11w:b7125b1aec598eb31bd58d82572bc11494e5dee4e8db2bdd29b88d41a16bdd996d2996ddec8c83741a1e8674e78328ba71737b8894a9271b1cd1399453d1952e43951d9b712822e
403 * and has an ambiguous area _and_ a situation where loop avoidance
404 * is a necessary deductive technique.
405 *
406 * Then there's
407 * 48x25w#820543338195187
408 * becoming
409 * 48x25w:255989d14cdd185deaa753a93821a12edc1ab97943ac127e2685d7b8b3c48861b2192416139212b316eddd35de43714ebc7628d753db32e596284d9ec52c5a7dc1b4c811a655117d16dc28921b2b4161352cab1d89d18bc836b8b891d55ea4622a1251861b5bc9a8aa3e5bcd745c95229ca6c3b5e21d5832d397e917325793d7eb442dc351b2db2a52ba8e1651642275842d8871d5534aabc6d5b741aaa2d48ed2a7dbbb3151ddb49d5b9a7ed1ab98ee75d613d656dbba347bc514c84556b43a9bc65a3256ead792488b862a9d2a8a39b4255a4949ed7dbd79443292521265896b4399c95ede89d7c8c797a6a57791a849adea489359a158aa12e5dacce862b8333b7ebea7d344d1a3c53198864b73a9dedde7b663abb1b539e1e8853b1b7edb14a2a17ebaae4dbe63598a2e7e9a2dbdad415bc1d8cb88cbab5a8c82925732cd282e641ea3bd7d2c6e776de9117a26be86deb7c82c89524b122cb9397cd1acd2284e744ea62b9279bae85479ababe315c3ac29c431333395b24e6a1e3c43a2da42d4dce84aadd5b154aea555eaddcbd6e527d228c19388d9b424d94214555a7edbdeebe569d4a56dc51a86bd9963e377bb74752bd5eaa5761ba545e297b62a1bda46ab4aee423ad6c661311783cc18786d4289236563cb4a75ec67d481c14814994464cd1b87396dee63e5ab6e952cc584baa1d4c47cb557ec84dbb63d487c8728118673a166846dd3a4ebc23d6cb9c5827d96b4556e91899db32b517eda815ae271a8911bd745447121dc8d321557bc2a435ebec1bbac35b1a291669451174e6aa2218a4a9c5a6ca31ebc45d84e3a82c121e9ced7d55e9a
410 * which has a spot (far right) where slightly more complex loop
411 * avoidance is required.
412 */
413
414struct todo {
415 unsigned char *marked;
416 int *buffer;
417 int buflen;
418 int head, tail;
419};
420
421static struct todo *todo_new(int maxsize)
422{
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;
429 return todo;
430}
431
432static void todo_free(struct todo *todo)
433{
434 sfree(todo->marked);
435 sfree(todo->buffer);
436 sfree(todo);
437}
438
439static void todo_add(struct todo *todo, int index)
440{
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)
446 todo->tail = 0;
447}
448
449static int todo_get(struct todo *todo) {
450 int ret;
451
452 if (todo->head == todo->tail)
453 return -1; /* list is empty */
454 ret = todo->buffer[todo->head++];
455 if (todo->head == todo->buflen)
456 todo->head = 0;
457 todo->marked[ret] = FALSE;
458
459 return ret;
460}
461
462static int net_solver(int w, int h, unsigned char *tiles,
463 unsigned char *barriers, int wrapping)
464{
465 unsigned char *tilestate;
466 unsigned char *edgestate;
467 int *deadends;
468 int *equivalence;
469 struct todo *todo;
470 int i, j, x, y;
471 int area;
472 int done_something;
473
474 /*
475 * Set up the solver's data structures.
476 */
477
478 /*
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.
484 *
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.)
490 */
491 tilestate = snewn(w * h * 4, unsigned char);
492 area = 0;
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;
499 else
500 tilestate[i * 4 + j] = A(tilestate[i * 4 + j - 1]);
501 }
502 if (tiles[i] != 0)
503 area++;
504 }
505
506 /*
507 * edgestate stores the known state of each edge. It is 0 for
508 * unknown, 1 for open (connected) and 2 for closed (not
509 * connected).
510 *
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.
517 */
518 edgestate = snewn((w * h - 1) * 5 + 9, unsigned char);
519 memset(edgestate, 0, (w * h - 1) * 5 + 9);
520
521 /*
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).
528 */
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;
532
533 /*
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
537 * another route.
538 *
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.
552 */
553 equivalence = snew_dsf(w * h);
554
555 /*
556 * On a non-wrapping grid, we instantly know that all the edges
557 * round the edge are closed.
558 */
559 if (!wrapping) {
560 for (i = 0; i < w; i++) {
561 edgestate[i * 5 + 2] = edgestate[((h-1) * w + i) * 5 + 8] = 2;
562 }
563 for (i = 0; i < h; i++) {
564 edgestate[(i * w + w-1) * 5 + 1] = edgestate[(i * w) * 5 + 4] = 2;
565 }
566 }
567
568 /*
569 * If we have barriers available, we can mark those edges as
570 * closed too.
571 */
572 if (barriers) {
573 for (y = 0; y < h; y++) for (x = 0; x < w; x++) {
574 int d;
575 for (d = 1; d <= 8; d += d) {
576 if (barriers[y*w+x] & d) {
577 int x2, y2;
578 /*
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
582 * consistency.
583 */
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;
587 }
588 }
589 }
590 }
591
592 /*
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.
599 */
600 todo = todo_new(w * h);
601
602 /*
603 * Main deductive loop.
604 */
605 done_something = TRUE; /* prevent instant termination! */
606 while (1) {
607 int index;
608
609 /*
610 * Take a tile index off the todo list and process it.
611 */
612 index = todo_get(todo);
613 if (index == -1) {
614 /*
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.
623 */
624 if (!done_something)
625 break;
626 for (i = 0; i < w*h; i++)
627 todo_add(todo, i);
628 done_something = FALSE;
629
630 index = todo_get(todo);
631 }
632
633 y = index / w;
634 x = index % w;
635 {
636 int d, ourclass = dsf_canonify(equivalence, y*w+x);
637 int deadendmax[9];
638
639 deadendmax[1] = deadendmax[2] = deadendmax[4] = deadendmax[8] = 0;
640
641 for (i = j = 0; i < 4 && tilestate[(y*w+x) * 4 + i] != 255; i++) {
642 int valid;
643 int nnondeadends, nondeadends[4], deadendtotal;
644 int nequiv, equiv[5];
645 int val = tilestate[(y*w+x) * 4 + i];
646
647 valid = TRUE;
648 nnondeadends = deadendtotal = 0;
649 equiv[0] = ourclass;
650 nequiv = 1;
651 for (d = 1; d <= 8; d += d) {
652 /*
653 * Immediately rule out this orientation if it
654 * conflicts with any known edge.
655 */
656 if ((edgestate[(y*w+x) * 5 + d] == 1 && !(val & d)) ||
657 (edgestate[(y*w+x) * 5 + d] == 2 && (val & d)))
658 valid = FALSE;
659
660 if (val & d) {
661 /*
662 * Count up the dead-end statistics.
663 */
664 if (deadends[(y*w+x) * 5 + d] <= area) {
665 deadendtotal += deadends[(y*w+x) * 5 + d];
666 } else {
667 nondeadends[nnondeadends++] = d;
668 }
669
670 /*
671 * Ensure we aren't linking to any tiles,
672 * through edges not already known to be
673 * open, which create a loop.
674 */
675 if (edgestate[(y*w+x) * 5 + d] == 0) {
676 int c, k, x2, y2;
677
678 OFFSETWH(x2, y2, x, y, d, w, h);
679 c = dsf_canonify(equivalence, y2*w+x2);
680 for (k = 0; k < nequiv; k++)
681 if (c == equiv[k])
682 break;
683 if (k == nequiv)
684 equiv[nequiv++] = c;
685 else
686 valid = FALSE;
687 }
688 }
689 }
690
691 if (nnondeadends == 0) {
692 /*
693 * If this orientation links together dead-ends
694 * with a total area of less than the entire
695 * grid, it is invalid.
696 *
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.)
701 */
702 if (deadendtotal > 0 && deadendtotal+1 < area)
703 valid = FALSE;
704 } else if (nnondeadends == 1) {
705 /*
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.
712 */
713 deadendtotal++;
714 if (deadendmax[nondeadends[0]] < deadendtotal)
715 deadendmax[nondeadends[0]] = deadendtotal;
716 } else {
717 /*
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.
722 */
723 int k;
724 for (k = 0; k < nnondeadends; k++)
725 deadendmax[nondeadends[k]] = area+1;
726 }
727
728 if (valid)
729 tilestate[(y*w+x) * 4 + j++] = val;
730#ifdef SOLVER_DIAGNOSTICS
731 else
732 printf("ruling out orientation %x at %d,%d\n", val, x, y);
733#endif
734 }
735
736 assert(j > 0); /* we can't lose _all_ possibilities! */
737
738 if (j < i) {
739 done_something = TRUE;
740
741 /*
742 * We have ruled out at least one tile orientation.
743 * Make sure the rest are blanked.
744 */
745 while (j < 4)
746 tilestate[(y*w+x) * 4 + j++] = 255;
747 }
748
749 /*
750 * Now go through the tile orientations again and see
751 * if we've deduced anything new about any edges.
752 */
753 {
754 int a, o;
755 a = 0xF; o = 0;
756
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];
760 }
761 for (d = 1; d <= 8; d += d)
762 if (edgestate[(y*w+x) * 5 + d] == 0) {
763 int x2, y2, d2;
764 OFFSETWH(x2, y2, x, y, d, w, h);
765 d2 = F(d);
766 if (a & d) {
767 /* This edge is open in all orientations. */
768#ifdef SOLVER_DIAGNOSTICS
769 printf("marking edge %d,%d:%d open\n", x, y, d);
770#endif
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);
780#endif
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);
785 }
786 }
787
788 }
789
790 /*
791 * Now check the dead-end markers and see if any of
792 * them has lowered from the real ones.
793 */
794 for (d = 1; d <= 8; d += d) {
795 int x2, y2, d2;
796 OFFSETWH(x2, y2, x, y, d, w, h);
797 d2 = F(d);
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]);
803#endif
804 deadends[(y2*w+x2) * 5 + d2] = deadendmax[d];
805 done_something = TRUE;
806 todo_add(todo, y2*w+x2);
807 }
808 }
809
810 }
811 }
812
813 /*
814 * Mark all completely determined tiles as locked.
815 */
816 j = TRUE;
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;
821 } else {
822 tiles[i] &= ~LOCKED;
823 j = FALSE;
824 }
825 }
826
827 /*
828 * Free up working space.
829 */
830 todo_free(todo);
831 sfree(tilestate);
832 sfree(edgestate);
833 sfree(deadends);
834 sfree(equivalence);
835
836 return j;
837}
838
839/* ----------------------------------------------------------------------
840 * Randomly select a new game description.
841 */
842
843/*
844 * Function to randomly perturb an ambiguous section in a grid, to
845 * attempt to ensure unique solvability.
846 */
847static void perturb(int w, int h, unsigned char *tiles, int wrapping,
848 random_state *rs, int startx, int starty, int startd)
849{
850 struct xyd *perimeter, *perim2, *loop[2], looppos[2];
851 int nperim, perimsize, nloop[2], loopsize[2];
852 int x, y, d, i;
853
854 /*
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.
859 */
860 nperim = perimsize = 0;
861 perimeter = NULL;
862 x = startx;
863 y = starty;
864 d = startd;
865#ifdef PERTURB_DIAGNOSTICS
866 printf("perturb %d,%d:%d\n", x, y, d);
867#endif
868 do {
869 int x2, y2, d2;
870
871 if (nperim >= perimsize) {
872 perimsize = perimsize * 3 / 2 + 32;
873 perimeter = sresize(perimeter, perimsize, struct xyd);
874 }
875 perimeter[nperim].x = x;
876 perimeter[nperim].y = y;
877 perimeter[nperim].direction = d;
878 nperim++;
879#ifdef PERTURB_DIAGNOSTICS
880 printf("perimeter: %d,%d:%d\n", x, y, d);
881#endif
882
883 /*
884 * First, see if we can simply turn left from where we are
885 * and find another locked square.
886 */
887 d2 = A(d);
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)) {
891 d = d2;
892 } else {
893 /*
894 * Failing that, step left into the new square and look
895 * in front of us.
896 */
897 x = x2;
898 y = y2;
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)) {
902 /*
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.
906 */
907 x = x2;
908 y = y2;
909 d = C(d);
910 }
911 }
912
913 } while (x != startx || y != starty || d != startd);
914
915 /*
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.
923 */
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++) {
929 int x2, y2;
930
931 x = perim2[i].x;
932 y = perim2[i].y;
933 d = perim2[i].direction;
934
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 */
944
945 /*
946 * We've found the point at which we're going to make a new
947 * link.
948 */
949#ifdef PERTURB_DIAGNOSTICS
950 printf("linking %d,%d:%d\n", x, y, d);
951#endif
952 tiles[y*w+x] |= d;
953 tiles[y2*w+x2] |= F(d);
954
955 break;
956 }
957 sfree(perim2);
958
959 if (i == nperim) {
960 sfree(perimeter);
961 return; /* nothing we can do! */
962 }
963
964 /*
965 * Now we've constructed a new link, we need to find the entire
966 * loop of which it is a part.
967 *
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.
975 */
976 for (i = 0; i < 2; i++) {
977 loopsize[i] = nloop[i] = 0;
978 loop[i] = NULL;
979 looppos[i].x = x;
980 looppos[i].y = y;
981 looppos[i].direction = d;
982 }
983 while (1) {
984 for (i = 0; i < 2; i++) {
985 int x2, y2, j;
986
987 x = looppos[i].x;
988 y = looppos[i].y;
989 d = looppos[i].direction;
990
991 OFFSETWH(x2, y2, x, y, d, w, h);
992
993 /*
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.
997 */
998#ifdef PERTURB_DIAGNOSTICS
999 printf("looppos[%d] = %d,%d:%d\n", i, x, y, d);
1000#endif
1001 if (nloop[i] > 0 &&
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",
1007 x2, y2, F(d), i);
1008#endif
1009 nloop[i]--;
1010 } else {
1011 if (nloop[i] >= loopsize[i]) {
1012 loopsize[i] = loopsize[i] * 3 / 2 + 32;
1013 loop[i] = sresize(loop[i], loopsize[i], struct xyd);
1014 }
1015#ifdef PERTURB_DIAGNOSTICS
1016 printf("adding path segment %d,%d:%d to loop[%d]\n",
1017 x, y, d, i);
1018#endif
1019 loop[i][nloop[i]++] = looppos[i];
1020 }
1021
1022#ifdef PERTURB_DIAGNOSTICS
1023 printf("tile at new location is %x\n", tiles[y2*w+x2] & 0xF);
1024#endif
1025 d = F(d);
1026 for (j = 0; j < 4; j++) {
1027 if (i == 0)
1028 d = A(d);
1029 else
1030 d = C(d);
1031#ifdef PERTURB_DIAGNOSTICS
1032 printf("trying dir %d\n", d);
1033#endif
1034 if (tiles[y2*w+x2] & d) {
1035 looppos[i].x = x2;
1036 looppos[i].y = y2;
1037 looppos[i].direction = d;
1038 break;
1039 }
1040 }
1041
1042 assert(j < 4);
1043 assert(nloop[i] > 0);
1044
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);
1050#endif
1051
1052 /*
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.
1058 */
1059 j = random_upto(rs, nloop[i]-1) + 1;
1060 x = loop[i][j].x;
1061 y = loop[i][j].y;
1062 d = loop[i][j].direction;
1063 OFFSETWH(x2, y2, x, y, d, w, h);
1064 tiles[y*w+x] &= ~d;
1065 tiles[y2*w+x2] &= ~F(d);
1066
1067 break;
1068 }
1069 }
1070 if (i < 2)
1071 break;
1072 }
1073 sfree(loop[0]);
1074 sfree(loop[1]);
1075
1076 /*
1077 * Finally, we must mark the entire disputed section as locked,
1078 * to prevent the perturb function being called on it multiple
1079 * times.
1080 *
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.
1086 */
1087 qsort(perimeter, nperim, sizeof(struct xyd), xyd_cmp);
1088 x = y = -1;
1089 for (i = 0; i <= nperim; i++) {
1090 if (i == nperim || perimeter[i].x > x) {
1091 /*
1092 * Fill in everything from the last Up edge to the
1093 * bottom of the grid, if necessary.
1094 */
1095 if (x != -1) {
1096 while (y < h) {
1097#ifdef PERTURB_DIAGNOSTICS
1098 printf("resolved: locking tile %d,%d\n", x, y);
1099#endif
1100 tiles[y * w + x] |= LOCKED;
1101 y++;
1102 }
1103 x = y = -1;
1104 }
1105
1106 if (i == nperim)
1107 break;
1108
1109 x = perimeter[i].x;
1110 y = 0;
1111 }
1112
1113 if (perimeter[i].direction == U) {
1114 x = perimeter[i].x;
1115 y = perimeter[i].y;
1116 } else if (perimeter[i].direction == D) {
1117 /*
1118 * Fill in everything from the last Up edge to here.
1119 */
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);
1124#endif
1125 tiles[y * w + x] |= LOCKED;
1126 y++;
1127 }
1128 x = y = -1;
1129 }
1130 }
1131
1132 sfree(perimeter);
1133}
1134
1135static int *compute_loops_inner(int w, int h, int wrapping,
1136 const unsigned char *tiles,
1137 const unsigned char *barriers);
1138
1139static char *new_game_desc(const game_params *params, random_state *rs,
1140 char **aux, int interactive)
1141{
1142 tree234 *possibilities, *barriertree;
1143 int w, h, x, y, cx, cy, nbarriers;
1144 unsigned char *tiles, *barriers;
1145 char *desc, *p;
1146
1147 w = params->width;
1148 h = params->height;
1149
1150 cx = w / 2;
1151 cy = h / 2;
1152
1153 tiles = snewn(w * h, unsigned char);
1154 barriers = snewn(w * h, unsigned char);
1155
1156 begin_generation:
1157
1158 memset(tiles, 0, w * h);
1159 memset(barriers, 0, w * h);
1160
1161 /*
1162 * Construct the unshuffled grid.
1163 *
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).
1171 *
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
1177 * full cross?
1178 *
1179 * Answer: no it can't, and here's a proof.
1180 *
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).
1189 *
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.
1195 *
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
1201 * closed loops. []
1202 */
1203 possibilities = newtree234(xyd_cmp_nc);
1204
1205 if (cx+1 < w)
1206 add234(possibilities, new_xyd(cx, cy, R));
1207 if (cy-1 >= 0)
1208 add234(possibilities, new_xyd(cx, cy, U));
1209 if (cx-1 >= 0)
1210 add234(possibilities, new_xyd(cx, cy, L));
1211 if (cy+1 < h)
1212 add234(possibilities, new_xyd(cx, cy, D));
1213
1214 while (count234(possibilities) > 0) {
1215 int i;
1216 struct xyd *xyd;
1217 int x1, y1, d1, x2, y2, d2, d;
1218
1219 /*
1220 * Extract a randomly chosen possibility from the list.
1221 */
1222 i = random_upto(rs, count234(possibilities));
1223 xyd = delpos234(possibilities, i);
1224 x1 = xyd->x;
1225 y1 = xyd->y;
1226 d1 = xyd->direction;
1227 sfree(xyd);
1228
1229 OFFSET(x2, y2, x1, y1, d1, params);
1230 d2 = F(d1);
1231#ifdef GENERATION_DIAGNOSTICS
1232 printf("picked (%d,%d,%c) <-> (%d,%d,%c)\n",
1233 x1, y1, "0RU3L567D9abcdef"[d1], x2, y2, "0RU3L567D9abcdef"[d2]);
1234#endif
1235
1236 /*
1237 * Make the connection. (We should be moving to an as yet
1238 * unused tile.)
1239 */
1240 index(params, tiles, x1, y1) |= d1;
1241 assert(index(params, tiles, x2, y2) == 0);
1242 index(params, tiles, x2, y2) |= d2;
1243
1244 /*
1245 * If we have created a T-piece, remove its last
1246 * possibility.
1247 */
1248 if (COUNT(index(params, tiles, x1, y1)) == 3) {
1249 struct xyd xyd1, *xydp;
1250
1251 xyd1.x = x1;
1252 xyd1.y = y1;
1253 xyd1.direction = 0x0F ^ index(params, tiles, x1, y1);
1254
1255 xydp = find234(possibilities, &xyd1, NULL);
1256
1257 if (xydp) {
1258#ifdef GENERATION_DIAGNOSTICS
1259 printf("T-piece; removing (%d,%d,%c)\n",
1260 xydp->x, xydp->y, "0RU3L567D9abcdef"[xydp->direction]);
1261#endif
1262 del234(possibilities, xydp);
1263 sfree(xydp);
1264 }
1265 }
1266
1267 /*
1268 * Remove all other possibilities that were pointing at the
1269 * tile we've just moved into.
1270 */
1271 for (d = 1; d < 0x10; d <<= 1) {
1272 int x3, y3, d3;
1273 struct xyd xyd1, *xydp;
1274
1275 OFFSET(x3, y3, x2, y2, d, params);
1276 d3 = F(d);
1277
1278 xyd1.x = x3;
1279 xyd1.y = y3;
1280 xyd1.direction = d3;
1281
1282 xydp = find234(possibilities, &xyd1, NULL);
1283
1284 if (xydp) {
1285#ifdef GENERATION_DIAGNOSTICS
1286 printf("Loop avoidance; removing (%d,%d,%c)\n",
1287 xydp->x, xydp->y, "0RU3L567D9abcdef"[xydp->direction]);
1288#endif
1289 del234(possibilities, xydp);
1290 sfree(xydp);
1291 }
1292 }
1293
1294 /*
1295 * Add new possibilities to the list for moving _out_ of
1296 * the tile we have just moved into.
1297 */
1298 for (d = 1; d < 0x10; d <<= 1) {
1299 int x3, y3;
1300
1301 if (d == d2)
1302 continue; /* we've got this one already */
1303
1304 if (!params->wrapping) {
1305 if (d == U && y2 == 0)
1306 continue;
1307 if (d == D && y2 == h-1)
1308 continue;
1309 if (d == L && x2 == 0)
1310 continue;
1311 if (d == R && x2 == w-1)
1312 continue;
1313 }
1314
1315 OFFSET(x3, y3, x2, y2, d, params);
1316
1317 if (index(params, tiles, x3, y3))
1318 continue; /* this would create a loop */
1319
1320#ifdef GENERATION_DIAGNOSTICS
1321 printf("New frontier; adding (%d,%d,%c)\n",
1322 x2, y2, "0RU3L567D9abcdef"[d]);
1323#endif
1324 add234(possibilities, new_xyd(x2, y2, d));
1325 }
1326 }
1327 /* Having done that, we should have no possibilities remaining. */
1328 assert(count234(possibilities) == 0);
1329 freetree234(possibilities);
1330
1331 if (params->unique) {
1332 int prevn = -1;
1333
1334 /*
1335 * Run the solver to check unique solubility.
1336 */
1337 while (!net_solver(w, h, tiles, NULL, params->wrapping)) {
1338 int n = 0;
1339
1340 /*
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
1346 * in that area.
1347 */
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)) {
1350 n++;
1351 if (tiles[y*w+x] & LOCKED)
1352 perturb(w, h, tiles, params->wrapping, rs, x+1, y, L);
1353 else
1354 perturb(w, h, tiles, params->wrapping, rs, x, y, R);
1355 }
1356 if (y+1 < h && ((tiles[y*w+x] ^ tiles[(y+1)*w+x]) & LOCKED)) {
1357 n++;
1358 if (tiles[y*w+x] & LOCKED)
1359 perturb(w, h, tiles, params->wrapping, rs, x, y+1, U);
1360 else
1361 perturb(w, h, tiles, params->wrapping, rs, x, y, D);
1362 }
1363 }
1364
1365 /*
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.
1370 */
1371 if (prevn != -1 && prevn <= n)
1372 goto begin_generation; /* (sorry) */
1373
1374 prevn = n;
1375 }
1376
1377 /*
1378 * The solver will have left a lot of LOCKED bits lying
1379 * around in the tiles array. Remove them.
1380 */
1381 for (x = 0; x < w*h; x++)
1382 tiles[x] &= ~LOCKED;
1383 }
1384
1385 /*
1386 * Now compute a list of the possible barrier locations.
1387 */
1388 barriertree = newtree234(xyd_cmp_nc);
1389 for (y = 0; y < h; y++) {
1390 for (x = 0; x < w; x++) {
1391
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));
1398 }
1399 }
1400
1401 /*
1402 * Save the unshuffled grid in aux.
1403 */
1404 {
1405 char *solution;
1406 int i;
1407
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';
1412
1413 *aux = solution;
1414 }
1415
1416 /*
1417 * Now shuffle the grid.
1418 *
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.
1422 *
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.
1430 *
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_
1436 * not solved.)
1437 *
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
1445 * endpoint.)
1446 */
1447 while (1) {
1448 int mismatches, prev_loopsquares, this_loopsquares, i;
1449 int *loops;
1450
1451 shuffle:
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);
1457 }
1458 }
1459
1460 /*
1461 * Check for loops, and try to fix them by reshuffling just
1462 * the squares involved.
1463 */
1464 prev_loopsquares = w*h+1;
1465 while (1) {
1466 loops = compute_loops_inner(w, h, params->wrapping, tiles, NULL);
1467 this_loopsquares = 0;
1468 for (i = 0; i < w*h; i++) {
1469 if (loops[i]) {
1470 int orig = tiles[i];
1471 int rot = random_upto(rs, 4);
1472 tiles[i] = ROT(orig, rot);
1473 this_loopsquares++;
1474 }
1475 }
1476 sfree(loops);
1477 if (this_loopsquares > prev_loopsquares) {
1478 /*
1479 * We're increasing rather than reducing the number of
1480 * loops. Give up and go back to the full shuffle.
1481 */
1482 goto shuffle;
1483 }
1484 if (this_loopsquares == 0)
1485 break;
1486 prev_loopsquares = this_loopsquares;
1487 }
1488
1489 mismatches = 0;
1490 /*
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.
1495 */
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))
1499 mismatches++;
1500 if (y+1 < h && ((ROT(index(params, tiles, x, y), 2) ^
1501 index(params, tiles, x, y+1)) & U))
1502 mismatches++;
1503 }
1504
1505 if (mismatches == 0)
1506 continue;
1507
1508 /* OK. */
1509 break;
1510 }
1511
1512 /*
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.)
1525 */
1526 nbarriers = (int)(params->barrier_probability * count234(barriertree));
1527 assert(nbarriers >= 0 && nbarriers <= count234(barriertree));
1528
1529 while (nbarriers > 0) {
1530 int i;
1531 struct xyd *xyd;
1532 int x1, y1, d1, x2, y2, d2;
1533
1534 /*
1535 * Extract a randomly chosen barrier from the list.
1536 */
1537 i = random_upto(rs, count234(barriertree));
1538 xyd = delpos234(barriertree, i);
1539
1540 assert(xyd != NULL);
1541
1542 x1 = xyd->x;
1543 y1 = xyd->y;
1544 d1 = xyd->direction;
1545 sfree(xyd);
1546
1547 OFFSET(x2, y2, x1, y1, d1, params);
1548 d2 = F(d1);
1549
1550 index(params, barriers, x1, y1) |= d1;
1551 index(params, barriers, x2, y2) |= d2;
1552
1553 nbarriers--;
1554 }
1555
1556 /*
1557 * Clean up the rest of the barrier list.
1558 */
1559 {
1560 struct xyd *xyd;
1561
1562 while ( (xyd = delpos234(barriertree, 0)) != NULL)
1563 sfree(xyd);
1564
1565 freetree234(barriertree);
1566 }
1567
1568 /*
1569 * Finally, encode the grid into a string game description.
1570 *
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
1577 * it.
1578 */
1579 desc = snewn(w * h * 3 + 1, char);
1580 p = desc;
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))
1586 *p++ = 'v';
1587 if ((params->wrapping || y < h-1) &&
1588 (index(params, barriers, x, y) & D))
1589 *p++ = 'h';
1590 }
1591 }
1592 assert(p - desc <= w*h*3);
1593 *p = '\0';
1594
1595 sfree(tiles);
1596 sfree(barriers);
1597
1598 return desc;
1599}
1600
1601static char *validate_desc(const game_params *params, const char *desc)
1602{
1603 int w = params->width, h = params->height;
1604 int i;
1605
1606 for (i = 0; i < w*h; i++) {
1607 if (*desc >= '0' && *desc <= '9')
1608 /* OK */;
1609 else if (*desc >= 'a' && *desc <= 'f')
1610 /* OK */;
1611 else if (*desc >= 'A' && *desc <= 'F')
1612 /* OK */;
1613 else if (!*desc)
1614 return "Game description shorter than expected";
1615 else
1616 return "Game description contained unexpected character";
1617 desc++;
1618 while (*desc == 'h' || *desc == 'v')
1619 desc++;
1620 }
1621 if (*desc)
1622 return "Game description longer than expected";
1623
1624 return NULL;
1625}
1626
1627/* ----------------------------------------------------------------------
1628 * Construct an initial game state, given a description and parameters.
1629 */
1630
1631static game_state *new_game(midend *me, const game_params *params,
1632 const char *desc)
1633{
1634 game_state *state;
1635 int w, h, x, y;
1636
1637 assert(params->width > 0 && params->height > 0);
1638 assert(params->width > 1 || params->height > 1);
1639
1640 /*
1641 * Create a blank game state.
1642 */
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);
1653
1654 /*
1655 * Parse the game description into the grid.
1656 */
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;
1665 if (*desc)
1666 desc++;
1667 while (*desc == 'h' || *desc == 'v') {
1668 int x2, y2, d1, d2;
1669 if (*desc == 'v')
1670 d1 = R;
1671 else
1672 d1 = D;
1673
1674 OFFSET(x2, y2, x, y, d1, state);
1675 d2 = F(d1);
1676
1677 barrier(state, x, y) |= d1;
1678 barrier(state, x2, y2) |= d2;
1679
1680 desc++;
1681 }
1682 }
1683 }
1684
1685 /*
1686 * Set up border barriers if this is a non-wrapping game.
1687 */
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;
1692 }
1693 for (y = 0; y < state->height; y++) {
1694 barrier(state, 0, y) |= L;
1695 barrier(state, state->width-1, y) |= R;
1696 }
1697 } else {
1698 /*
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.
1703 */
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;
1713 }
1714
1715 return state;
1716}
1717
1718static game_state *dup_game(const game_state *state)
1719{
1720 game_state *ret;
1721
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);
1735
1736 return ret;
1737}
1738
1739static void free_game(game_state *state)
1740{
1741 sfree(state->tiles);
1742 sfree(state->barriers);
1743 sfree(state);
1744}
1745
1746static char *solve_game(const game_state *state, const game_state *currstate,
1747 const char *aux, char **error)
1748{
1749 unsigned char *tiles;
1750 char *ret;
1751 int retlen, retsize;
1752 int i;
1753
1754 tiles = snewn(state->width * state->height, unsigned char);
1755
1756 if (!aux) {
1757 /*
1758 * Run the internal solver on the provided grid. This might
1759 * not yield a complete solution.
1760 */
1761 memcpy(tiles, state->tiles, state->width * state->height);
1762 net_solver(state->width, state->height, tiles,
1763 state->barriers, state->wrapping);
1764 } else {
1765 for (i = 0; i < state->width * state->height; i++) {
1766 int c = aux[i];
1767
1768 if (c >= '0' && c <= '9')
1769 tiles[i] = c - '0';
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;
1774
1775 tiles[i] |= LOCKED;
1776 }
1777 }
1778
1779 /*
1780 * Now construct a string which can be passed to execute_move()
1781 * to transform the current grid into the solved one.
1782 */
1783 retsize = 256;
1784 ret = snewn(retsize, char);
1785 retlen = 0;
1786 ret[retlen++] = 'S';
1787
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;
1792 int chr = '\0';
1793 char buf[80], *p = buf;
1794
1795 if (from == to)
1796 continue; /* nothing needs doing at all */
1797
1798 /*
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.
1802 */
1803 if (from & LOCKED)
1804 p += sprintf(p, ";L%d,%d", x, y);
1805
1806 if (tt == A(ft))
1807 chr = 'A';
1808 else if (tt == C(ft))
1809 chr = 'C';
1810 else if (tt == F(ft))
1811 chr = 'F';
1812 else {
1813 assert(tt == ft);
1814 chr = '\0';
1815 }
1816 if (chr)
1817 p += sprintf(p, ";%c%d,%d", chr, x, y);
1818
1819 if (to & LOCKED)
1820 p += sprintf(p, ";L%d,%d", x, y);
1821
1822 if (p > buf) {
1823 if (retlen + (p - buf) >= retsize) {
1824 retsize = retlen + (p - buf) + 512;
1825 ret = sresize(ret, retsize, char);
1826 }
1827 memcpy(ret+retlen, buf, p - buf);
1828 retlen += p - buf;
1829 }
1830 }
1831
1832 assert(retlen < retsize);
1833 ret[retlen] = '\0';
1834 ret = sresize(ret, retlen+1, char);
1835
1836 sfree(tiles);
1837
1838 return ret;
1839}
1840
1841static int game_can_format_as_text_now(const game_params *params)
1842{
1843 return TRUE;
1844}
1845
1846static char *game_text_format(const game_state *state)
1847{
1848 return NULL;
1849}
1850
1851/* ----------------------------------------------------------------------
1852 * Utility routine.
1853 */
1854
1855/*
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
1860 * is marked active.
1861 */
1862static unsigned char *compute_active(const game_state *state, int cx, int cy)
1863{
1864 unsigned char *active;
1865 tree234 *todo;
1866 struct xyd *xyd;
1867
1868 active = snewn(state->width * state->height, unsigned char);
1869 memset(active, 0, state->width * state->height);
1870
1871 /*
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.
1874 */
1875 todo = newtree234(xyd_cmp_nc);
1876 index(state, active, cx, cy) = ACTIVE;
1877 add234(todo, new_xyd(cx, cy, 0));
1878
1879 while ( (xyd = delpos234(todo, 0)) != NULL) {
1880 int x1, y1, d1, x2, y2, d2;
1881
1882 x1 = xyd->x;
1883 y1 = xyd->y;
1884 sfree(xyd);
1885
1886 for (d1 = 1; d1 < 0x10; d1 <<= 1) {
1887 OFFSET(x2, y2, x1, y1, d1, state);
1888 d2 = F(d1);
1889
1890 /*
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.
1895 */
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));
1902 }
1903 }
1904 }
1905 /* Now we expect the todo list to have shrunk to zero size. */
1906 assert(count234(todo) == 0);
1907 freetree234(todo);
1908
1909 return active;
1910}
1911
1912struct net_neighbour_ctx {
1913 int w, h;
1914 const unsigned char *tiles, *barriers;
1915 int i, n, neighbours[4];
1916};
1917static int net_neighbour(int vertex, void *vctx)
1918{
1919 struct net_neighbour_ctx *ctx = (struct net_neighbour_ctx *)vctx;
1920
1921 if (vertex >= 0) {
1922 int x = vertex % ctx->w, y = vertex / ctx->w;
1923 int tile, dir, x1, y1, v1;
1924
1925 ctx->i = ctx->n = 0;
1926
1927 tile = ctx->tiles[vertex];
1928 if (ctx->barriers)
1929 tile &= ~ctx->barriers[vertex];
1930
1931 for (dir = 1; dir < 0x10; dir <<= 1) {
1932 if (!(tile & dir))
1933 continue;
1934 OFFSETWH(x1, y1, x, y, dir, ctx->w, ctx->h);
1935 v1 = y1 * ctx->w + x1;
1936 if (ctx->tiles[v1] & F(dir))
1937 ctx->neighbours[ctx->n++] = v1;
1938 }
1939 }
1940
1941 if (ctx->i < ctx->n)
1942 return ctx->neighbours[ctx->i++];
1943 else
1944 return -1;
1945}
1946
1947static int *compute_loops_inner(int w, int h, int wrapping,
1948 const unsigned char *tiles,
1949 const unsigned char *barriers)
1950{
1951 struct net_neighbour_ctx ctx;
1952 struct findloopstate *fls;
1953 int *loops;
1954 int x, y;
1955
1956 fls = findloop_new_state(w*h);
1957 ctx.w = w;
1958 ctx.h = h;
1959 ctx.tiles = tiles;
1960 ctx.barriers = barriers;
1961 findloop_run(fls, w*h, net_neighbour, &ctx);
1962
1963 loops = snewn(w*h, int);
1964
1965 for (y = 0; y < h; y++) {
1966 for (x = 0; x < w; x++) {
1967 int x1, y1, dir;
1968 int flags = 0;
1969
1970 for (dir = 1; dir < 0x10; dir <<= 1) {
1971 if ((tiles[y*w+x] & dir) &&
1972 !(barriers && (barriers[y*w+x] & dir))) {
1973 OFFSETWH(x1, y1, x, y, dir, w, h);
1974 if ((tiles[y1*w+x1] & F(dir)) &&
1975 findloop_is_loop_edge(fls, y*w+x, y1*w+x1))
1976 flags |= LOOP(dir);
1977 }
1978 }
1979 loops[y*w+x] = flags;
1980 }
1981 }
1982
1983 findloop_free_state(fls);
1984 return loops;
1985}
1986
1987static int *compute_loops(const game_state *state)
1988{
1989 return compute_loops_inner(state->width, state->height, state->wrapping,
1990 state->tiles, state->barriers);
1991}
1992
1993struct game_ui {
1994 int org_x, org_y; /* origin */
1995 int cx, cy; /* source tile (game coordinates) */
1996 int cur_x, cur_y;
1997 int cur_visible;
1998 random_state *rs; /* used for jumbling */
1999#ifdef USE_DRAGGING
2000 int dragtilex, dragtiley, dragstartx, dragstarty, dragged;
2001#endif
2002};
2003
2004static game_ui *new_ui(const game_state *state)
2005{
2006 void *seed;
2007 int seedsize;
2008 game_ui *ui = snew(game_ui);
2009 ui->org_x = ui->org_y = 0;
2010 ui->cur_x = ui->cx = state->width / 2;
2011 ui->cur_y = ui->cy = state->height / 2;
2012 ui->cur_visible = FALSE;
2013 get_random_seed(&seed, &seedsize);
2014 ui->rs = random_new(seed, seedsize);
2015 sfree(seed);
2016
2017 return ui;
2018}
2019
2020static void free_ui(game_ui *ui)
2021{
2022 random_free(ui->rs);
2023 sfree(ui);
2024}
2025
2026static char *encode_ui(const game_ui *ui)
2027{
2028 char buf[120];
2029 /*
2030 * We preserve the origin and centre-point coordinates over a
2031 * serialise.
2032 */
2033 sprintf(buf, "O%d,%d;C%d,%d", ui->org_x, ui->org_y, ui->cx, ui->cy);
2034 return dupstr(buf);
2035}
2036
2037static void decode_ui(game_ui *ui, const char *encoding)
2038{
2039 sscanf(encoding, "O%d,%d;C%d,%d",
2040 &ui->org_x, &ui->org_y, &ui->cx, &ui->cy);
2041}
2042
2043static void game_changed_state(game_ui *ui, const game_state *oldstate,
2044 const game_state *newstate)
2045{
2046}
2047
2048struct game_drawstate {
2049 int started;
2050 int width, height;
2051 int org_x, org_y;
2052 int tilesize;
2053 int *visible;
2054};
2055
2056/* ----------------------------------------------------------------------
2057 * Process a move.
2058 */
2059static char *interpret_move(const game_state *state, game_ui *ui,
2060 const game_drawstate *ds,
2061 int x, int y, int button)
2062{
2063 char *nullret;
2064 int tx = -1, ty = -1, dir = 0;
2065 int shift = button & MOD_SHFT, ctrl = button & MOD_CTRL;
2066 enum {
2067 NONE, ROTATE_LEFT, ROTATE_180, ROTATE_RIGHT, TOGGLE_LOCK, JUMBLE,
2068 MOVE_ORIGIN, MOVE_SOURCE, MOVE_ORIGIN_AND_SOURCE, MOVE_CURSOR
2069 } action;
2070
2071 button &= ~MOD_MASK;
2072 nullret = NULL;
2073 action = NONE;
2074
2075 if (button == LEFT_BUTTON ||
2076 button == MIDDLE_BUTTON ||
2077#ifdef USE_DRAGGING
2078 button == LEFT_DRAG ||
2079 button == LEFT_RELEASE ||
2080 button == RIGHT_DRAG ||
2081 button == RIGHT_RELEASE ||
2082#endif
2083 button == RIGHT_BUTTON) {
2084
2085 if (ui->cur_visible) {
2086 ui->cur_visible = FALSE;
2087 nullret = "";
2088 }
2089
2090 /*
2091 * The button must have been clicked on a valid tile.
2092 */
2093 x -= WINDOW_OFFSET + TILE_BORDER;
2094 y -= WINDOW_OFFSET + TILE_BORDER;
2095 if (x < 0 || y < 0)
2096 return nullret;
2097 tx = x / TILE_SIZE;
2098 ty = y / TILE_SIZE;
2099 if (tx >= state->width || ty >= state->height)
2100 return nullret;
2101 /* Transform from physical to game coords */
2102 tx = (tx + ui->org_x) % state->width;
2103 ty = (ty + ui->org_y) % state->height;
2104 if (x % TILE_SIZE >= TILE_SIZE - TILE_BORDER ||
2105 y % TILE_SIZE >= TILE_SIZE - TILE_BORDER)
2106 return nullret;
2107
2108#ifdef USE_DRAGGING
2109
2110 if (button == MIDDLE_BUTTON
2111#ifdef STYLUS_BASED
2112 || button == RIGHT_BUTTON /* with a stylus, `right-click' locks */
2113#endif
2114 ) {
2115 /*
2116 * Middle button never drags: it only toggles the lock.
2117 */
2118 action = TOGGLE_LOCK;
2119 } else if (button == LEFT_BUTTON
2120#ifndef STYLUS_BASED
2121 || button == RIGHT_BUTTON /* (see above) */
2122#endif
2123 ) {
2124 /*
2125 * Otherwise, we note down the start point for a drag.
2126 */
2127 ui->dragtilex = tx;
2128 ui->dragtiley = ty;
2129 ui->dragstartx = x % TILE_SIZE;
2130 ui->dragstarty = y % TILE_SIZE;
2131 ui->dragged = FALSE;
2132 return nullret; /* no actual action */
2133 } else if (button == LEFT_DRAG
2134#ifndef STYLUS_BASED
2135 || button == RIGHT_DRAG
2136#endif
2137 ) {
2138 /*
2139 * Find the new drag point and see if it necessitates a
2140 * rotation.
2141 */
2142 int x0,y0, xA,yA, xC,yC, xF,yF;
2143 int mx, my;
2144 int d0, dA, dC, dF, dmin;
2145
2146 tx = ui->dragtilex;
2147 ty = ui->dragtiley;
2148
2149 mx = x - (ui->dragtilex * TILE_SIZE);
2150 my = y - (ui->dragtiley * TILE_SIZE);
2151
2152 x0 = ui->dragstartx;
2153 y0 = ui->dragstarty;
2154 xA = ui->dragstarty;
2155 yA = TILE_SIZE-1 - ui->dragstartx;
2156 xF = TILE_SIZE-1 - ui->dragstartx;
2157 yF = TILE_SIZE-1 - ui->dragstarty;
2158 xC = TILE_SIZE-1 - ui->dragstarty;
2159 yC = ui->dragstartx;
2160
2161 d0 = (mx-x0)*(mx-x0) + (my-y0)*(my-y0);
2162 dA = (mx-xA)*(mx-xA) + (my-yA)*(my-yA);
2163 dF = (mx-xF)*(mx-xF) + (my-yF)*(my-yF);
2164 dC = (mx-xC)*(mx-xC) + (my-yC)*(my-yC);
2165
2166 dmin = min(min(d0,dA),min(dF,dC));
2167
2168 if (d0 == dmin) {
2169 return nullret;
2170 } else if (dF == dmin) {
2171 action = ROTATE_180;
2172 ui->dragstartx = xF;
2173 ui->dragstarty = yF;
2174 ui->dragged = TRUE;
2175 } else if (dA == dmin) {
2176 action = ROTATE_LEFT;
2177 ui->dragstartx = xA;
2178 ui->dragstarty = yA;
2179 ui->dragged = TRUE;
2180 } else /* dC == dmin */ {
2181 action = ROTATE_RIGHT;
2182 ui->dragstartx = xC;
2183 ui->dragstarty = yC;
2184 ui->dragged = TRUE;
2185 }
2186 } else if (button == LEFT_RELEASE
2187#ifndef STYLUS_BASED
2188 || button == RIGHT_RELEASE
2189#endif
2190 ) {
2191 if (!ui->dragged) {
2192 /*
2193 * There was a click but no perceptible drag:
2194 * revert to single-click behaviour.
2195 */
2196 tx = ui->dragtilex;
2197 ty = ui->dragtiley;
2198
2199 if (button == LEFT_RELEASE)
2200 action = ROTATE_LEFT;
2201 else
2202 action = ROTATE_RIGHT;
2203 } else
2204 return nullret; /* no action */
2205 }
2206
2207#else /* USE_DRAGGING */
2208
2209 action = (button == LEFT_BUTTON ? ROTATE_LEFT :
2210 button == RIGHT_BUTTON ? ROTATE_RIGHT : TOGGLE_LOCK);
2211
2212#endif /* USE_DRAGGING */
2213
2214 } else if (IS_CURSOR_MOVE(button)) {
2215 switch (button) {
2216 case CURSOR_UP: dir = U; break;
2217 case CURSOR_DOWN: dir = D; break;
2218 case CURSOR_LEFT: dir = L; break;
2219 case CURSOR_RIGHT: dir = R; break;
2220 default: return nullret;
2221 }
2222 if (shift && ctrl) action = MOVE_ORIGIN_AND_SOURCE;
2223 else if (shift) action = MOVE_ORIGIN;
2224 else if (ctrl) action = MOVE_SOURCE;
2225 else action = MOVE_CURSOR;
2226 } else if (button == 'a' || button == 's' || button == 'd' ||
2227 button == 'A' || button == 'S' || button == 'D' ||
2228 button == 'f' || button == 'F' ||
2229 IS_CURSOR_SELECT(button)) {
2230 tx = ui->cur_x;
2231 ty = ui->cur_y;
2232 if (button == 'a' || button == 'A' || button == CURSOR_SELECT)
2233 action = ROTATE_LEFT;
2234 else if (button == 's' || button == 'S' || button == CURSOR_SELECT2)
2235 action = TOGGLE_LOCK;
2236 else if (button == 'd' || button == 'D')
2237 action = ROTATE_RIGHT;
2238 else if (button == 'f' || button == 'F')
2239 action = ROTATE_180;
2240 ui->cur_visible = TRUE;
2241 } else if (button == 'j' || button == 'J') {
2242 /* XXX should we have some mouse control for this? */
2243 action = JUMBLE;
2244 } else
2245 return nullret;
2246
2247 /*
2248 * The middle button locks or unlocks a tile. (A locked tile
2249 * cannot be turned, and is visually marked as being locked.
2250 * This is a convenience for the player, so that once they are
2251 * sure which way round a tile goes, they can lock it and thus
2252 * avoid forgetting later on that they'd already done that one;
2253 * and the locking also prevents them turning the tile by
2254 * accident. If they change their mind, another middle click
2255 * unlocks it.)
2256 */
2257 if (action == TOGGLE_LOCK) {
2258 char buf[80];
2259 sprintf(buf, "L%d,%d", tx, ty);
2260 return dupstr(buf);
2261 } else if (action == ROTATE_LEFT || action == ROTATE_RIGHT ||
2262 action == ROTATE_180) {
2263 char buf[80];
2264
2265 /*
2266 * The left and right buttons have no effect if clicked on a
2267 * locked tile.
2268 */
2269 if (tile(state, tx, ty) & LOCKED)
2270 return nullret;
2271
2272 /*
2273 * Otherwise, turn the tile one way or the other. Left button
2274 * turns anticlockwise; right button turns clockwise.
2275 */
2276 sprintf(buf, "%c%d,%d", (int)(action == ROTATE_LEFT ? 'A' :
2277 action == ROTATE_RIGHT ? 'C' : 'F'), tx, ty);
2278 return dupstr(buf);
2279 } else if (action == JUMBLE) {
2280 /*
2281 * Jumble all unlocked tiles to random orientations.
2282 */
2283
2284 int jx, jy, maxlen;
2285 char *ret, *p;
2286
2287 /*
2288 * Maximum string length assumes no int can be converted to
2289 * decimal and take more than 11 digits!
2290 */
2291 maxlen = state->width * state->height * 25 + 3;
2292
2293 ret = snewn(maxlen, char);
2294 p = ret;
2295 *p++ = 'J';
2296
2297 for (jy = 0; jy < state->height; jy++) {
2298 for (jx = 0; jx < state->width; jx++) {
2299 if (!(tile(state, jx, jy) & LOCKED)) {
2300 int rot = random_upto(ui->rs, 4);
2301 if (rot) {
2302 p += sprintf(p, ";%c%d,%d", "AFC"[rot-1], jx, jy);
2303 }
2304 }
2305 }
2306 }
2307 *p++ = '\0';
2308 assert(p - ret < maxlen);
2309 ret = sresize(ret, p - ret, char);
2310
2311 return ret;
2312 } else if (action == MOVE_ORIGIN || action == MOVE_SOURCE ||
2313 action == MOVE_ORIGIN_AND_SOURCE || action == MOVE_CURSOR) {
2314 assert(dir != 0);
2315 if (action == MOVE_ORIGIN || action == MOVE_ORIGIN_AND_SOURCE) {
2316 if (state->wrapping) {
2317 OFFSET(ui->org_x, ui->org_y, ui->org_x, ui->org_y, dir, state);
2318 } else return nullret; /* disallowed for non-wrapping grids */
2319 }
2320 if (action == MOVE_SOURCE || action == MOVE_ORIGIN_AND_SOURCE) {
2321 OFFSET(ui->cx, ui->cy, ui->cx, ui->cy, dir, state);
2322 }
2323 if (action == MOVE_CURSOR) {
2324 OFFSET(ui->cur_x, ui->cur_y, ui->cur_x, ui->cur_y, dir, state);
2325 ui->cur_visible = TRUE;
2326 }
2327 return "";
2328 } else {
2329 return NULL;
2330 }
2331}
2332
2333static game_state *execute_move(const game_state *from, const char *move)
2334{
2335 game_state *ret;
2336 int tx = -1, ty = -1, n, noanim, orig;
2337
2338 ret = dup_game(from);
2339
2340 if (move[0] == 'J' || move[0] == 'S') {
2341 if (move[0] == 'S')
2342 ret->used_solve = TRUE;
2343
2344 move++;
2345 if (*move == ';')
2346 move++;
2347 noanim = TRUE;
2348 } else
2349 noanim = FALSE;
2350
2351 ret->last_rotate_dir = 0; /* suppress animation */
2352 ret->last_rotate_x = ret->last_rotate_y = 0;
2353
2354 while (*move) {
2355 if ((move[0] == 'A' || move[0] == 'C' ||
2356 move[0] == 'F' || move[0] == 'L') &&
2357 sscanf(move+1, "%d,%d%n", &tx, &ty, &n) >= 2 &&
2358 tx >= 0 && tx < from->width && ty >= 0 && ty < from->height) {
2359 orig = tile(ret, tx, ty);
2360 if (move[0] == 'A') {
2361 tile(ret, tx, ty) = A(orig);
2362 if (!noanim)
2363 ret->last_rotate_dir = +1;
2364 } else if (move[0] == 'F') {
2365 tile(ret, tx, ty) = F(orig);
2366 if (!noanim)
2367 ret->last_rotate_dir = +2; /* + for sake of argument */
2368 } else if (move[0] == 'C') {
2369 tile(ret, tx, ty) = C(orig);
2370 if (!noanim)
2371 ret->last_rotate_dir = -1;
2372 } else {
2373 assert(move[0] == 'L');
2374 tile(ret, tx, ty) ^= LOCKED;
2375 }
2376
2377 move += 1 + n;
2378 if (*move == ';') move++;
2379 } else {
2380 free_game(ret);
2381 return NULL;
2382 }
2383 }
2384 if (!noanim) {
2385 if (tx == -1 || ty == -1) { free_game(ret); return NULL; }
2386 ret->last_rotate_x = tx;
2387 ret->last_rotate_y = ty;
2388 }
2389
2390 /*
2391 * Check whether the game has been completed.
2392 *
2393 * For this purpose it doesn't matter where the source square is,
2394 * because we can start from anywhere (or, at least, any square
2395 * that's non-empty!), and correctly determine whether the game is
2396 * completed.
2397 */
2398 {
2399 unsigned char *active;
2400 int pos;
2401 int complete = TRUE;
2402
2403 for (pos = 0; pos < ret->width * ret->height; pos++)
2404 if (ret->tiles[pos] & 0xF)
2405 break;
2406
2407 if (pos < ret->width * ret->height) {
2408 active = compute_active(ret, pos % ret->width, pos / ret->width);
2409
2410 for (pos = 0; pos < ret->width * ret->height; pos++)
2411 if ((ret->tiles[pos] & 0xF) && !active[pos]) {
2412 complete = FALSE;
2413 break;
2414 }
2415
2416 sfree(active);
2417 }
2418
2419 if (complete)
2420 ret->completed = TRUE;
2421 }
2422
2423 return ret;
2424}
2425
2426
2427/* ----------------------------------------------------------------------
2428 * Routines for drawing the game position on the screen.
2429 */
2430
2431static game_drawstate *game_new_drawstate(drawing *dr, const game_state *state)
2432{
2433 game_drawstate *ds = snew(game_drawstate);
2434 int i;
2435
2436 ds->started = FALSE;
2437 ds->width = state->width;
2438 ds->height = state->height;
2439 ds->org_x = ds->org_y = -1;
2440 ds->visible = snewn(state->width * state->height, int);
2441 ds->tilesize = 0; /* undecided yet */
2442 for (i = 0; i < state->width * state->height; i++)
2443 ds->visible[i] = -1;
2444
2445 return ds;
2446}
2447
2448static void game_free_drawstate(drawing *dr, game_drawstate *ds)
2449{
2450 sfree(ds->visible);
2451 sfree(ds);
2452}
2453
2454static void game_compute_size(const game_params *params, int tilesize,
2455 int *x, int *y)
2456{
2457 *x = WINDOW_OFFSET * 2 + tilesize * params->width + TILE_BORDER;
2458 *y = WINDOW_OFFSET * 2 + tilesize * params->height + TILE_BORDER;
2459}
2460
2461static void game_set_size(drawing *dr, game_drawstate *ds,
2462 const game_params *params, int tilesize)
2463{
2464 ds->tilesize = tilesize;
2465}
2466
2467static float *game_colours(frontend *fe, int *ncolours)
2468{
2469 float *ret;
2470
2471 ret = snewn(NCOLOURS * 3, float);
2472 *ncolours = NCOLOURS;
2473
2474 /*
2475 * Basic background colour is whatever the front end thinks is
2476 * a sensible default.
2477 */
2478 frontend_default_colour(fe, &ret[COL_BACKGROUND * 3]);
2479
2480 /*
2481 * Wires are black.
2482 */
2483 ret[COL_WIRE * 3 + 0] = 0.0F;
2484 ret[COL_WIRE * 3 + 1] = 0.0F;
2485 ret[COL_WIRE * 3 + 2] = 0.0F;
2486
2487 /*
2488 * Powered wires and powered endpoints are cyan.
2489 */
2490 ret[COL_POWERED * 3 + 0] = 0.0F;
2491 ret[COL_POWERED * 3 + 1] = 1.0F;
2492 ret[COL_POWERED * 3 + 2] = 1.0F;
2493
2494 /*
2495 * Barriers are red.
2496 */
2497 ret[COL_BARRIER * 3 + 0] = 1.0F;
2498 ret[COL_BARRIER * 3 + 1] = 0.0F;
2499 ret[COL_BARRIER * 3 + 2] = 0.0F;
2500
2501 /*
2502 * Highlighted loops are red as well.
2503 */
2504 ret[COL_LOOP * 3 + 0] = 1.0F;
2505 ret[COL_LOOP * 3 + 1] = 0.0F;
2506 ret[COL_LOOP * 3 + 2] = 0.0F;
2507
2508 /*
2509 * Unpowered endpoints are blue.
2510 */
2511 ret[COL_ENDPOINT * 3 + 0] = 0.0F;
2512 ret[COL_ENDPOINT * 3 + 1] = 0.0F;
2513 ret[COL_ENDPOINT * 3 + 2] = 1.0F;
2514
2515 /*
2516 * Tile borders are a darker grey than the background.
2517 */
2518 ret[COL_BORDER * 3 + 0] = 0.5F * ret[COL_BACKGROUND * 3 + 0];
2519 ret[COL_BORDER * 3 + 1] = 0.5F * ret[COL_BACKGROUND * 3 + 1];
2520 ret[COL_BORDER * 3 + 2] = 0.5F * ret[COL_BACKGROUND * 3 + 2];
2521
2522 /*
2523 * Locked tiles are a grey in between those two.
2524 */
2525 ret[COL_LOCKED * 3 + 0] = 0.75F * ret[COL_BACKGROUND * 3 + 0];
2526 ret[COL_LOCKED * 3 + 1] = 0.75F * ret[COL_BACKGROUND * 3 + 1];
2527 ret[COL_LOCKED * 3 + 2] = 0.75F * ret[COL_BACKGROUND * 3 + 2];
2528
2529 return ret;
2530}
2531
2532static void draw_filled_line(drawing *dr, int x1, int y1, int x2, int y2,
2533 int colour)
2534{
2535 draw_line(dr, x1-1, y1, x2-1, y2, COL_WIRE);
2536 draw_line(dr, x1+1, y1, x2+1, y2, COL_WIRE);
2537 draw_line(dr, x1, y1-1, x2, y2-1, COL_WIRE);
2538 draw_line(dr, x1, y1+1, x2, y2+1, COL_WIRE);
2539 draw_line(dr, x1, y1, x2, y2, colour);
2540}
2541
2542static void draw_rect_coords(drawing *dr, int x1, int y1, int x2, int y2,
2543 int colour)
2544{
2545 int mx = (x1 < x2 ? x1 : x2);
2546 int my = (y1 < y2 ? y1 : y2);
2547 int dx = (x2 + x1 - 2*mx + 1);
2548 int dy = (y2 + y1 - 2*my + 1);
2549
2550 draw_rect(dr, mx, my, dx, dy, colour);
2551}
2552
2553/*
2554 * draw_barrier_corner() and draw_barrier() are passed physical coords
2555 */
2556static void draw_barrier_corner(drawing *dr, game_drawstate *ds,
2557 int x, int y, int dx, int dy, int phase)
2558{
2559 int bx = WINDOW_OFFSET + TILE_SIZE * x;
2560 int by = WINDOW_OFFSET + TILE_SIZE * y;
2561 int x1, y1;
2562
2563 x1 = (dx > 0 ? TILE_SIZE+TILE_BORDER-1 : 0);
2564 y1 = (dy > 0 ? TILE_SIZE+TILE_BORDER-1 : 0);
2565
2566 if (phase == 0) {
2567 draw_rect_coords(dr, bx+x1+dx, by+y1,
2568 bx+x1-TILE_BORDER*dx, by+y1-(TILE_BORDER-1)*dy,
2569 COL_WIRE);
2570 draw_rect_coords(dr, bx+x1, by+y1+dy,
2571 bx+x1-(TILE_BORDER-1)*dx, by+y1-TILE_BORDER*dy,
2572 COL_WIRE);
2573 } else {
2574 draw_rect_coords(dr, bx+x1, by+y1,
2575 bx+x1-(TILE_BORDER-1)*dx, by+y1-(TILE_BORDER-1)*dy,
2576 COL_BARRIER);
2577 }
2578}
2579
2580static void draw_barrier(drawing *dr, game_drawstate *ds,
2581 int x, int y, int dir, int phase)
2582{
2583 int bx = WINDOW_OFFSET + TILE_SIZE * x;
2584 int by = WINDOW_OFFSET + TILE_SIZE * y;
2585 int x1, y1, w, h;
2586
2587 x1 = (X(dir) > 0 ? TILE_SIZE : X(dir) == 0 ? TILE_BORDER : 0);
2588 y1 = (Y(dir) > 0 ? TILE_SIZE : Y(dir) == 0 ? TILE_BORDER : 0);
2589 w = (X(dir) ? TILE_BORDER : TILE_SIZE - TILE_BORDER);
2590 h = (Y(dir) ? TILE_BORDER : TILE_SIZE - TILE_BORDER);
2591
2592 if (phase == 0) {
2593 draw_rect(dr, bx+x1-X(dir), by+y1-Y(dir), w, h, COL_WIRE);
2594 } else {
2595 draw_rect(dr, bx+x1, by+y1, w, h, COL_BARRIER);
2596 }
2597}
2598
2599/*
2600 * draw_tile() is passed physical coordinates
2601 */
2602static void draw_tile(drawing *dr, const game_state *state, game_drawstate *ds,
2603 int x, int y, int tile, int src, float angle, int cursor)
2604{
2605 int bx = WINDOW_OFFSET + TILE_SIZE * x;
2606 int by = WINDOW_OFFSET + TILE_SIZE * y;
2607 float matrix[4];
2608 float cx, cy, ex, ey, tx, ty;
2609 int dir, col, phase;
2610
2611 /*
2612 * When we draw a single tile, we must draw everything up to
2613 * and including the borders around the tile. This means that
2614 * if the neighbouring tiles have connections to those borders,
2615 * we must draw those connections on the borders themselves.
2616 */
2617
2618 clip(dr, bx, by, TILE_SIZE+TILE_BORDER, TILE_SIZE+TILE_BORDER);
2619
2620 /*
2621 * So. First blank the tile out completely: draw a big
2622 * rectangle in border colour, and a smaller rectangle in
2623 * background colour to fill it in.
2624 */
2625 draw_rect(dr, bx, by, TILE_SIZE+TILE_BORDER, TILE_SIZE+TILE_BORDER,
2626 COL_BORDER);
2627 draw_rect(dr, bx+TILE_BORDER, by+TILE_BORDER,
2628 TILE_SIZE-TILE_BORDER, TILE_SIZE-TILE_BORDER,
2629 tile & LOCKED ? COL_LOCKED : COL_BACKGROUND);
2630
2631 /*
2632 * Draw an inset outline rectangle as a cursor, in whichever of
2633 * COL_LOCKED and COL_BACKGROUND we aren't currently drawing
2634 * in.
2635 */
2636 if (cursor) {
2637 draw_line(dr, bx+TILE_SIZE/8, by+TILE_SIZE/8,
2638 bx+TILE_SIZE/8, by+TILE_SIZE-TILE_SIZE/8,
2639 tile & LOCKED ? COL_BACKGROUND : COL_LOCKED);
2640 draw_line(dr, bx+TILE_SIZE/8, by+TILE_SIZE/8,
2641 bx+TILE_SIZE-TILE_SIZE/8, by+TILE_SIZE/8,
2642 tile & LOCKED ? COL_BACKGROUND : COL_LOCKED);
2643 draw_line(dr, bx+TILE_SIZE-TILE_SIZE/8, by+TILE_SIZE/8,
2644 bx+TILE_SIZE-TILE_SIZE/8, by+TILE_SIZE-TILE_SIZE/8,
2645 tile & LOCKED ? COL_BACKGROUND : COL_LOCKED);
2646 draw_line(dr, bx+TILE_SIZE/8, by+TILE_SIZE-TILE_SIZE/8,
2647 bx+TILE_SIZE-TILE_SIZE/8, by+TILE_SIZE-TILE_SIZE/8,
2648 tile & LOCKED ? COL_BACKGROUND : COL_LOCKED);
2649 }
2650
2651 /*
2652 * Set up the rotation matrix.
2653 */
2654 matrix[0] = (float)cos(angle * PI / 180.0);
2655 matrix[1] = (float)-sin(angle * PI / 180.0);
2656 matrix[2] = (float)sin(angle * PI / 180.0);
2657 matrix[3] = (float)cos(angle * PI / 180.0);
2658
2659 /*
2660 * Draw the wires.
2661 */
2662 cx = cy = TILE_BORDER + (TILE_SIZE-TILE_BORDER) / 2.0F - 0.5F;
2663 col = (tile & ACTIVE ? COL_POWERED : COL_WIRE);
2664 for (dir = 1; dir < 0x10; dir <<= 1) {
2665 if (tile & dir) {
2666 ex = (TILE_SIZE - TILE_BORDER - 1.0F) / 2.0F * X(dir);
2667 ey = (TILE_SIZE - TILE_BORDER - 1.0F) / 2.0F * Y(dir);
2668 MATMUL(tx, ty, matrix, ex, ey);
2669 draw_filled_line(dr, bx+(int)cx, by+(int)cy,
2670 bx+(int)(cx+tx), by+(int)(cy+ty),
2671 COL_WIRE);
2672 }
2673 }
2674 for (dir = 1; dir < 0x10; dir <<= 1) {
2675 if (tile & dir) {
2676 ex = (TILE_SIZE - TILE_BORDER - 1.0F) / 2.0F * X(dir);
2677 ey = (TILE_SIZE - TILE_BORDER - 1.0F) / 2.0F * Y(dir);
2678 MATMUL(tx, ty, matrix, ex, ey);
2679 draw_line(dr, bx+(int)cx, by+(int)cy,
2680 bx+(int)(cx+tx), by+(int)(cy+ty),
2681 (tile & LOOP(dir)) ? COL_LOOP : col);
2682 }
2683 }
2684 /* If we've drawn any loop-highlighted arms, make sure the centre
2685 * point is loop-coloured rather than a later arm overwriting it. */
2686 if (tile & (RLOOP | ULOOP | LLOOP | DLOOP))
2687 draw_rect(dr, bx+(int)cx, by+(int)cy, 1, 1, COL_LOOP);
2688
2689 /*
2690 * Draw the box in the middle. We do this in blue if the tile
2691 * is an unpowered endpoint, in cyan if the tile is a powered
2692 * endpoint, in black if the tile is the centrepiece, and
2693 * otherwise not at all.
2694 */
2695 col = -1;
2696 if (src)
2697 col = COL_WIRE;
2698 else if (COUNT(tile) == 1) {
2699 col = (tile & ACTIVE ? COL_POWERED : COL_ENDPOINT);
2700 }
2701 if (col >= 0) {
2702 int i, points[8];
2703
2704 points[0] = +1; points[1] = +1;
2705 points[2] = +1; points[3] = -1;
2706 points[4] = -1; points[5] = -1;
2707 points[6] = -1; points[7] = +1;
2708
2709 for (i = 0; i < 8; i += 2) {
2710 ex = (TILE_SIZE * 0.24F) * points[i];
2711 ey = (TILE_SIZE * 0.24F) * points[i+1];
2712 MATMUL(tx, ty, matrix, ex, ey);
2713 points[i] = bx+(int)(cx+tx);
2714 points[i+1] = by+(int)(cy+ty);
2715 }
2716
2717 draw_polygon(dr, points, 4, col, COL_WIRE);
2718 }
2719
2720 /*
2721 * Draw the points on the border if other tiles are connected
2722 * to us.
2723 */
2724 for (dir = 1; dir < 0x10; dir <<= 1) {
2725 int dx, dy, px, py, lx, ly, vx, vy, ox, oy;
2726
2727 dx = X(dir);
2728 dy = Y(dir);
2729
2730 ox = x + dx;
2731 oy = y + dy;
2732
2733 if (ox < 0 || ox >= state->width || oy < 0 || oy >= state->height)
2734 continue;
2735
2736 if (!(tile(state, GX(ox), GY(oy)) & F(dir)))
2737 continue;
2738
2739 px = bx + (int)(dx>0 ? TILE_SIZE + TILE_BORDER - 1 : dx<0 ? 0 : cx);
2740 py = by + (int)(dy>0 ? TILE_SIZE + TILE_BORDER - 1 : dy<0 ? 0 : cy);
2741 lx = dx * (TILE_BORDER-1);
2742 ly = dy * (TILE_BORDER-1);
2743 vx = (dy ? 1 : 0);
2744 vy = (dx ? 1 : 0);
2745
2746 if (angle == 0.0 && (tile & dir)) {
2747 /*
2748 * If we are fully connected to the other tile, we must
2749 * draw right across the tile border. (We can use our
2750 * own ACTIVE state to determine what colour to do this
2751 * in: if we are fully connected to the other tile then
2752 * the two ACTIVE states will be the same.)
2753 */
2754 draw_rect_coords(dr, px-vx, py-vy, px+lx+vx, py+ly+vy, COL_WIRE);
2755 draw_rect_coords(dr, px, py, px+lx, py+ly,
2756 ((tile & LOOP(dir)) ? COL_LOOP :
2757 (tile & ACTIVE) ? COL_POWERED :
2758 COL_WIRE));
2759 } else {
2760 /*
2761 * The other tile extends into our border, but isn't
2762 * actually connected to us. Just draw a single black
2763 * dot.
2764 */
2765 draw_rect_coords(dr, px, py, px, py, COL_WIRE);
2766 }
2767 }
2768
2769 /*
2770 * Draw barrier corners, and then barriers.
2771 */
2772 for (phase = 0; phase < 2; phase++) {
2773 for (dir = 1; dir < 0x10; dir <<= 1) {
2774 int x1, y1, corner = FALSE;
2775 /*
2776 * If at least one barrier terminates at the corner
2777 * between dir and A(dir), draw a barrier corner.
2778 */
2779 if (barrier(state, GX(x), GY(y)) & (dir | A(dir))) {
2780 corner = TRUE;
2781 } else {
2782 /*
2783 * Only count barriers terminating at this corner
2784 * if they're physically next to the corner. (That
2785 * is, if they've wrapped round from the far side
2786 * of the screen, they don't count.)
2787 */
2788 x1 = x + X(dir);
2789 y1 = y + Y(dir);
2790 if (x1 >= 0 && x1 < state->width &&
2791 y1 >= 0 && y1 < state->height &&
2792 (barrier(state, GX(x1), GY(y1)) & A(dir))) {
2793 corner = TRUE;
2794 } else {
2795 x1 = x + X(A(dir));
2796 y1 = y + Y(A(dir));
2797 if (x1 >= 0 && x1 < state->width &&
2798 y1 >= 0 && y1 < state->height &&
2799 (barrier(state, GX(x1), GY(y1)) & dir))
2800 corner = TRUE;
2801 }
2802 }
2803
2804 if (corner) {
2805 /*
2806 * At least one barrier terminates here. Draw a
2807 * corner.
2808 */
2809 draw_barrier_corner(dr, ds, x, y,
2810 X(dir)+X(A(dir)), Y(dir)+Y(A(dir)),
2811 phase);
2812 }
2813 }
2814
2815 for (dir = 1; dir < 0x10; dir <<= 1)
2816 if (barrier(state, GX(x), GY(y)) & dir)
2817 draw_barrier(dr, ds, x, y, dir, phase);
2818 }
2819
2820 unclip(dr);
2821
2822 draw_update(dr, bx, by, TILE_SIZE+TILE_BORDER, TILE_SIZE+TILE_BORDER);
2823}
2824
2825static void game_redraw(drawing *dr, game_drawstate *ds,
2826 const game_state *oldstate, const game_state *state,
2827 int dir, const game_ui *ui,
2828 float t, float ft)
2829{
2830 int x, y, tx, ty, frame, last_rotate_dir, moved_origin = FALSE;
2831 unsigned char *active;
2832 int *loops;
2833 float angle = 0.0;
2834
2835 /*
2836 * Clear the screen, and draw the exterior barrier lines, if
2837 * this is our first call or if the origin has changed.
2838 */
2839 if (!ds->started || ui->org_x != ds->org_x || ui->org_y != ds->org_y) {
2840 int phase;
2841
2842 ds->started = TRUE;
2843
2844 draw_rect(dr, 0, 0,
2845 WINDOW_OFFSET * 2 + TILE_SIZE * state->width + TILE_BORDER,
2846 WINDOW_OFFSET * 2 + TILE_SIZE * state->height + TILE_BORDER,
2847 COL_BACKGROUND);
2848
2849 ds->org_x = ui->org_x;
2850 ds->org_y = ui->org_y;
2851 moved_origin = TRUE;
2852
2853 draw_update(dr, 0, 0,
2854 WINDOW_OFFSET*2 + TILE_SIZE*state->width + TILE_BORDER,
2855 WINDOW_OFFSET*2 + TILE_SIZE*state->height + TILE_BORDER);
2856
2857 for (phase = 0; phase < 2; phase++) {
2858
2859 for (x = 0; x < ds->width; x++) {
2860 if (x+1 < ds->width) {
2861 if (barrier(state, GX(x), GY(0)) & R)
2862 draw_barrier_corner(dr, ds, x, -1, +1, +1, phase);
2863 if (barrier(state, GX(x), GY(ds->height-1)) & R)
2864 draw_barrier_corner(dr, ds, x, ds->height, +1, -1, phase);
2865 }
2866 if (barrier(state, GX(x), GY(0)) & U) {
2867 draw_barrier_corner(dr, ds, x, -1, -1, +1, phase);
2868 draw_barrier_corner(dr, ds, x, -1, +1, +1, phase);
2869 draw_barrier(dr, ds, x, -1, D, phase);
2870 }
2871 if (barrier(state, GX(x), GY(ds->height-1)) & D) {
2872 draw_barrier_corner(dr, ds, x, ds->height, -1, -1, phase);
2873 draw_barrier_corner(dr, ds, x, ds->height, +1, -1, phase);
2874 draw_barrier(dr, ds, x, ds->height, U, phase);
2875 }
2876 }
2877
2878 for (y = 0; y < ds->height; y++) {
2879 if (y+1 < ds->height) {
2880 if (barrier(state, GX(0), GY(y)) & D)
2881 draw_barrier_corner(dr, ds, -1, y, +1, +1, phase);
2882 if (barrier(state, GX(ds->width-1), GY(y)) & D)
2883 draw_barrier_corner(dr, ds, ds->width, y, -1, +1, phase);
2884 }
2885 if (barrier(state, GX(0), GY(y)) & L) {
2886 draw_barrier_corner(dr, ds, -1, y, +1, -1, phase);
2887 draw_barrier_corner(dr, ds, -1, y, +1, +1, phase);
2888 draw_barrier(dr, ds, -1, y, R, phase);
2889 }
2890 if (barrier(state, GX(ds->width-1), GY(y)) & R) {
2891 draw_barrier_corner(dr, ds, ds->width, y, -1, -1, phase);
2892 draw_barrier_corner(dr, ds, ds->width, y, -1, +1, phase);
2893 draw_barrier(dr, ds, ds->width, y, L, phase);
2894 }
2895 }
2896 }
2897 }
2898
2899 tx = ty = -1;
2900 last_rotate_dir = dir==-1 ? oldstate->last_rotate_dir :
2901 state->last_rotate_dir;
2902 if (oldstate && (t < ROTATE_TIME) && last_rotate_dir) {
2903 /*
2904 * We're animating a single tile rotation. Find the turning
2905 * tile.
2906 */
2907 tx = (dir==-1 ? oldstate->last_rotate_x : state->last_rotate_x);
2908 ty = (dir==-1 ? oldstate->last_rotate_y : state->last_rotate_y);
2909 angle = last_rotate_dir * dir * 90.0F * (t / ROTATE_TIME);
2910 state = oldstate;
2911 }
2912
2913 frame = -1;
2914 if (ft > 0) {
2915 /*
2916 * We're animating a completion flash. Find which frame
2917 * we're at.
2918 */
2919 frame = (int)(ft / FLASH_FRAME);
2920 }
2921
2922 /*
2923 * Draw any tile which differs from the way it was last drawn.
2924 */
2925 active = compute_active(state, ui->cx, ui->cy);
2926 loops = compute_loops(state);
2927
2928 for (x = 0; x < ds->width; x++)
2929 for (y = 0; y < ds->height; y++) {
2930 int c = tile(state, GX(x), GY(y)) |
2931 index(state, active, GX(x), GY(y)) |
2932 index(state, loops, GX(x), GY(y));
2933 int is_src = GX(x) == ui->cx && GY(y) == ui->cy;
2934 int is_anim = GX(x) == tx && GY(y) == ty;
2935 int is_cursor = ui->cur_visible &&
2936 GX(x) == ui->cur_x && GY(y) == ui->cur_y;
2937
2938 /*
2939 * In a completion flash, we adjust the LOCKED bit
2940 * depending on our distance from the centre point and
2941 * the frame number.
2942 */
2943 if (frame >= 0) {
2944 int rcx = RX(ui->cx), rcy = RY(ui->cy);
2945 int xdist, ydist, dist;
2946 xdist = (x < rcx ? rcx - x : x - rcx);
2947 ydist = (y < rcy ? rcy - y : y - rcy);
2948 dist = (xdist > ydist ? xdist : ydist);
2949
2950 if (frame >= dist && frame < dist+4) {
2951 int lock = (frame - dist) & 1;
2952 lock = lock ? LOCKED : 0;
2953 c = (c &~ LOCKED) | lock;
2954 }
2955 }
2956
2957 if (moved_origin ||
2958 index(state, ds->visible, x, y) != c ||
2959 index(state, ds->visible, x, y) == -1 ||
2960 is_src || is_anim || is_cursor) {
2961 draw_tile(dr, state, ds, x, y, c,
2962 is_src, (is_anim ? angle : 0.0F), is_cursor);
2963 if (is_src || is_anim || is_cursor)
2964 index(state, ds->visible, x, y) = -1;
2965 else
2966 index(state, ds->visible, x, y) = c;
2967 }
2968 }
2969
2970 /*
2971 * Update the status bar.
2972 */
2973 {
2974 char statusbuf[256], *p;
2975 int i, n, n2, a;
2976 int complete = FALSE;
2977
2978 p = statusbuf;
2979 *p = '\0'; /* ensure even an empty status string is terminated */
2980
2981 if (state->used_solve) {
2982 p += sprintf(p, "Auto-solved. ");
2983 complete = TRUE;
2984 } else if (state->completed) {
2985 p += sprintf(p, "COMPLETED! ");
2986 complete = TRUE;
2987 }
2988
2989 /*
2990 * Omit the 'Active: n/N' counter completely if the source
2991 * tile is a completely empty one, because then the active
2992 * count can't help but read '1'.
2993 */
2994 if (tile(state, ui->cx, ui->cy) & 0xF) {
2995 n = state->width * state->height;
2996 for (i = a = n2 = 0; i < n; i++) {
2997 if (active[i])
2998 a++;
2999 if (state->tiles[i] & 0xF)
3000 n2++;
3001 }
3002
3003 /*
3004 * Also, if we're displaying a completion indicator and
3005 * the game is still in its completed state (i.e. every
3006 * tile is active), we might as well omit this too.
3007 */
3008 if (!complete || a < n2)
3009 p += sprintf(p, "Active: %d/%d", a, n2);
3010 }
3011
3012 status_bar(dr, statusbuf);
3013 }
3014
3015 sfree(active);
3016 sfree(loops);
3017}
3018
3019static float game_anim_length(const game_state *oldstate,
3020 const game_state *newstate, int dir, game_ui *ui)
3021{
3022 int last_rotate_dir;
3023
3024 /*
3025 * Don't animate if last_rotate_dir is zero.
3026 */
3027 last_rotate_dir = dir==-1 ? oldstate->last_rotate_dir :
3028 newstate->last_rotate_dir;
3029 if (last_rotate_dir)
3030 return ROTATE_TIME;
3031
3032 return 0.0F;
3033}
3034
3035static float game_flash_length(const game_state *oldstate,
3036 const game_state *newstate, int dir, game_ui *ui)
3037{
3038 /*
3039 * If the game has just been completed, we display a completion
3040 * flash.
3041 */
3042 if (!oldstate->completed && newstate->completed &&
3043 !oldstate->used_solve && !newstate->used_solve) {
3044 int size = 0;
3045 if (size < newstate->width)
3046 size = newstate->width;
3047 if (size < newstate->height)
3048 size = newstate->height;
3049 return FLASH_FRAME * (size+4);
3050 }
3051
3052 return 0.0F;
3053}
3054
3055static int game_status(const game_state *state)
3056{
3057 return state->completed ? +1 : 0;
3058}
3059
3060static int game_timing_state(const game_state *state, game_ui *ui)
3061{
3062 return TRUE;
3063}
3064
3065static void game_print_size(const game_params *params, float *x, float *y)
3066{
3067 int pw, ph;
3068
3069 /*
3070 * I'll use 8mm squares by default.
3071 */
3072 game_compute_size(params, 800, &pw, &ph);
3073 *x = pw / 100.0F;
3074 *y = ph / 100.0F;
3075}
3076
3077static void draw_diagram(drawing *dr, game_drawstate *ds, int x, int y,
3078 int topleft, int v, int drawlines, int ink)
3079{
3080 int tx, ty, cx, cy, r, br, k, thick;
3081
3082 tx = WINDOW_OFFSET + TILE_SIZE * x;
3083 ty = WINDOW_OFFSET + TILE_SIZE * y;
3084
3085 /*
3086 * Find our centre point.
3087 */
3088 if (topleft) {
3089 cx = tx + (v & L ? TILE_SIZE / 4 : TILE_SIZE / 6);
3090 cy = ty + (v & U ? TILE_SIZE / 4 : TILE_SIZE / 6);
3091 r = TILE_SIZE / 8;
3092 br = TILE_SIZE / 32;
3093 } else {
3094 cx = tx + TILE_SIZE / 2;
3095 cy = ty + TILE_SIZE / 2;
3096 r = TILE_SIZE / 2;
3097 br = TILE_SIZE / 8;
3098 }
3099 thick = r / 20;
3100
3101 /*
3102 * Draw the square block if we have an endpoint.
3103 */
3104 if (v == 1 || v == 2 || v == 4 || v == 8)
3105 draw_rect(dr, cx - br, cy - br, br*2, br*2, ink);
3106
3107 /*
3108 * Draw each radial line.
3109 */
3110 if (drawlines) {
3111 for (k = 1; k < 16; k *= 2)
3112 if (v & k) {
3113 int x1 = min(cx, cx + (r-thick) * X(k));
3114 int x2 = max(cx, cx + (r-thick) * X(k));
3115 int y1 = min(cy, cy + (r-thick) * Y(k));
3116 int y2 = max(cy, cy + (r-thick) * Y(k));
3117 draw_rect(dr, x1 - thick, y1 - thick,
3118 (x2 - x1) + 2*thick, (y2 - y1) + 2*thick, ink);
3119 }
3120 }
3121}
3122
3123static void game_print(drawing *dr, const game_state *state, int tilesize)
3124{
3125 int w = state->width, h = state->height;
3126 int ink = print_mono_colour(dr, 0);
3127 int x, y;
3128
3129 /* Ick: fake up `ds->tilesize' for macro expansion purposes */
3130 game_drawstate ads, *ds = &ads;
3131 game_set_size(dr, ds, NULL, tilesize);
3132
3133 /*
3134 * Border.
3135 */
3136 print_line_width(dr, TILE_SIZE / (state->wrapping ? 128 : 12));
3137 draw_rect_outline(dr, WINDOW_OFFSET, WINDOW_OFFSET,
3138 TILE_SIZE * w, TILE_SIZE * h, ink);
3139
3140 /*
3141 * Grid.
3142 */
3143 print_line_width(dr, TILE_SIZE / 128);
3144 for (x = 1; x < w; x++)
3145 draw_line(dr, WINDOW_OFFSET + TILE_SIZE * x, WINDOW_OFFSET,
3146 WINDOW_OFFSET + TILE_SIZE * x, WINDOW_OFFSET + TILE_SIZE * h,
3147 ink);
3148 for (y = 1; y < h; y++)
3149 draw_line(dr, WINDOW_OFFSET, WINDOW_OFFSET + TILE_SIZE * y,
3150 WINDOW_OFFSET + TILE_SIZE * w, WINDOW_OFFSET + TILE_SIZE * y,
3151 ink);
3152
3153 /*
3154 * Barriers.
3155 */
3156 for (y = 0; y <= h; y++)
3157 for (x = 0; x <= w; x++) {
3158 int b = barrier(state, x % w, y % h);
3159 if (x < w && (b & U))
3160 draw_rect(dr, WINDOW_OFFSET + TILE_SIZE * x - TILE_SIZE/24,
3161 WINDOW_OFFSET + TILE_SIZE * y - TILE_SIZE/24,
3162 TILE_SIZE + TILE_SIZE/24 * 2, TILE_SIZE/24 * 2, ink);
3163 if (y < h && (b & L))
3164 draw_rect(dr, WINDOW_OFFSET + TILE_SIZE * x - TILE_SIZE/24,
3165 WINDOW_OFFSET + TILE_SIZE * y - TILE_SIZE/24,
3166 TILE_SIZE/24 * 2, TILE_SIZE + TILE_SIZE/24 * 2, ink);
3167 }
3168
3169 /*
3170 * Grid contents.
3171 */
3172 for (y = 0; y < h; y++)
3173 for (x = 0; x < w; x++) {
3174 int vx, v = tile(state, x, y);
3175 int locked = v & LOCKED;
3176
3177 v &= 0xF;
3178
3179 /*
3180 * Rotate into a standard orientation for the top left
3181 * corner diagram.
3182 */
3183 vx = v;
3184 while (vx != 0 && vx != 15 && vx != 1 && vx != 9 && vx != 13 &&
3185 vx != 5)
3186 vx = A(vx);
3187
3188 /*
3189 * Draw the top left corner diagram.
3190 */
3191 draw_diagram(dr, ds, x, y, TRUE, vx, TRUE, ink);
3192
3193 /*
3194 * Draw the real solution diagram, if we're doing so.
3195 */
3196 draw_diagram(dr, ds, x, y, FALSE, v, locked, ink);
3197 }
3198}
3199
3200#ifdef COMBINED
3201#define thegame net
3202#endif
3203
3204const struct game thegame = {
3205 "Net", "games.net", "net",
3206 default_params,
3207 game_fetch_preset, NULL,
3208 decode_params,
3209 encode_params,
3210 free_params,
3211 dup_params,
3212 TRUE, game_configure, custom_params,
3213 validate_params,
3214 new_game_desc,
3215 validate_desc,
3216 new_game,
3217 dup_game,
3218 free_game,
3219 TRUE, solve_game,
3220 FALSE, game_can_format_as_text_now, game_text_format,
3221 new_ui,
3222 free_ui,
3223 encode_ui,
3224 decode_ui,
3225 game_changed_state,
3226 interpret_move,
3227 execute_move,
3228 PREFERRED_TILE_SIZE, game_compute_size, game_set_size,
3229 game_colours,
3230 game_new_drawstate,
3231 game_free_drawstate,
3232 game_redraw,
3233 game_anim_length,
3234 game_flash_length,
3235 game_status,
3236 TRUE, FALSE, game_print_size, game_print,
3237 TRUE, /* wants_statusbar */
3238 FALSE, game_timing_state,
3239 0, /* flags */
3240};
generated by cgit v1.2.3 (git 2.39.1) at 2024-09-17 22:41:48 +0000