X-Git-Url: http://www.chiark.greenend.org.uk/ucgi/~ian/git?a=blobdiff_plain;f=net.c;h=57d91d3581c5af92029ad219e505fa7db3f3c22f;hb=a0a581c8b5422bf0c5ed3fde6aa25811e4eb89fc;hp=a5fe8c0d698c10fcc7f134b4d805de46f7efd2ae;hpb=3663603627809a11908dc1dfadd158cfde8e0672;p=sgt-puzzles.git diff --git a/net.c b/net.c index a5fe8c0..57d91d3 100644 --- a/net.c +++ b/net.c @@ -6,16 +6,46 @@ #include #include #include +#include +#include #include "puzzles.h" #include "tree234.h" -/* Direction bitfields */ +/* + * The standard user interface for Net simply has left- and + * right-button mouse clicks in a square rotate it one way or the + * other. We also provide, by #ifdef, a separate interface based on + * rotational dragging motions. I initially developed this for the + * Mac on the basis that it might work better than the click + * interface with only one mouse button available, but in fact + * found it to be quite strange and unintuitive. Apparently it + * works better on stylus-driven platforms such as Palm and + * PocketPC, though, so we enable it by default there. + */ +#ifdef STYLUS_BASED +#define USE_DRAGGING +#endif + +#define MATMUL(xr,yr,m,x,y) do { \ + float rx, ry, xx = (x), yy = (y), *mat = (m); \ + rx = mat[0] * xx + mat[2] * yy; \ + ry = mat[1] * xx + mat[3] * yy; \ + (xr) = rx; (yr) = ry; \ +} while (0) + +/* Direction and other bitfields */ #define R 0x01 #define U 0x02 #define L 0x04 #define D 0x08 #define LOCKED 0x10 +#define ACTIVE 0x20 +#define RLOOP (R << 6) +#define ULOOP (U << 6) +#define LLOOP (L << 6) +#define DLOOP (D << 6) +#define LOOP(dir) ((dir) << 6) /* Rotations: Anticlockwise, Clockwise, Flip, general rotate */ #define A(x) ( (((x) & 0x07) << 1) | (((x) & 0x08) >> 3) ) @@ -33,26 +63,59 @@ #define COUNT(x) ( (((x) & 0x08) >> 3) + (((x) & 0x04) >> 2) + \ (((x) & 0x02) >> 1) + ((x) & 0x01) ) -#define TILE_SIZE 32 +#define PREFERRED_TILE_SIZE 32 +#define TILE_SIZE (ds->tilesize) #define TILE_BORDER 1 +#ifdef SMALL_SCREEN +#define WINDOW_OFFSET 4 +#else #define WINDOW_OFFSET 16 +#endif + +#define ROTATE_TIME 0.13F +#define FLASH_FRAME 0.07F + +/* Transform physical coords to game coords using game_drawstate ds */ +#define GX(x) (((x) + ds->org_x) % ds->width) +#define GY(y) (((y) + ds->org_y) % ds->height) +/* ...and game coords to physical coords */ +#define RX(x) (((x) + ds->width - ds->org_x) % ds->width) +#define RY(y) (((y) + ds->height - ds->org_y) % ds->height) + +enum { + COL_BACKGROUND, + COL_LOCKED, + COL_BORDER, + COL_WIRE, + COL_ENDPOINT, + COL_POWERED, + COL_BARRIER, + COL_LOOP, + NCOLOURS +}; struct game_params { int width; int height; int wrapping; + int unique; float barrier_probability; }; struct game_state { int width, height, wrapping, completed; + int last_rotate_x, last_rotate_y, last_rotate_dir; + int used_solve; unsigned char *tiles; unsigned char *barriers; }; +#define OFFSETWH(x2,y2,x1,y1,dir,width,height) \ + ( (x2) = ((x1) + width + X((dir))) % width, \ + (y2) = ((y1) + height + Y((dir))) % height) + #define OFFSET(x2,y2,x1,y1,dir,state) \ - ( (x2) = ((x1) + (state)->width + X((dir))) % (state)->width, \ - (y2) = ((y1) + (state)->height + Y((dir))) % (state)->height) + OFFSETWH(x2,y2,x1,y1,dir,(state)->width,(state)->height) #define index(state, a, x, y) ( a[(y) * (state)->width + (x)] ) #define tile(state, x, y) index(state, (state)->tiles, x, y) @@ -62,9 +125,9 @@ struct xyd { int x, y, direction; }; -static int xyd_cmp(void *av, void *bv) { - struct xyd *a = (struct xyd *)av; - struct xyd *b = (struct xyd *)bv; +static int xyd_cmp(const void *av, const void *bv) { + const struct xyd *a = (const struct xyd *)av; + const struct xyd *b = (const struct xyd *)bv; if (a->x < b->x) return -1; if (a->x > b->x) @@ -78,7 +141,9 @@ static int xyd_cmp(void *av, void *bv) { if (a->direction > b->direction) return +1; return 0; -}; +} + +static int xyd_cmp_nc(void *av, void *bv) { return xyd_cmp(av, bv); } static struct xyd *new_xyd(int x, int y, int direction) { @@ -90,539 +155,3103 @@ static struct xyd *new_xyd(int x, int y, int direction) } /* ---------------------------------------------------------------------- - * Randomly select a new game seed. + * Manage game parameters. */ - -char *new_game_seed(game_params *params) +static game_params *default_params(void) { - /* - * The full description of a Net game is far too large to - * encode directly in the seed, so by default we'll have to go - * for the simple approach of providing a random-number seed. - * - * (This does not restrict me from _later on_ inventing a seed - * string syntax which can never be generated by this code - - * for example, strings beginning with a letter - allowing me - * to type in a precise game, and have new_game detect it and - * understand it and do something completely different.) - */ - char buf[40]; - sprintf(buf, "%d", rand()); - return dupstr(buf); + game_params *ret = snew(game_params); + + ret->width = 5; + ret->height = 5; + ret->wrapping = FALSE; + ret->unique = TRUE; + ret->barrier_probability = 0.0; + + return ret; } -/* ---------------------------------------------------------------------- - * Construct an initial game state, given a seed and parameters. - */ +static const struct game_params net_presets[] = { + {5, 5, FALSE, TRUE, 0.0}, + {7, 7, FALSE, TRUE, 0.0}, + {9, 9, FALSE, TRUE, 0.0}, + {11, 11, FALSE, TRUE, 0.0}, +#ifndef SMALL_SCREEN + {13, 11, FALSE, TRUE, 0.0}, +#endif + {5, 5, TRUE, TRUE, 0.0}, + {7, 7, TRUE, TRUE, 0.0}, + {9, 9, TRUE, TRUE, 0.0}, + {11, 11, TRUE, TRUE, 0.0}, +#ifndef SMALL_SCREEN + {13, 11, TRUE, TRUE, 0.0}, +#endif +}; -game_state *new_game(game_params *params, char *seed) +static int game_fetch_preset(int i, char **name, game_params **params) { - random_state *rs; - game_state *state; - tree234 *possibilities, *barriers; - int w, h, x, y, nbarriers; + game_params *ret; + char str[80]; - assert(params->width > 2); - assert(params->height > 2); + if (i < 0 || i >= lenof(net_presets)) + return FALSE; - /* - * Create a blank game state. - */ - state = snew(game_state); - w = state->width = params->width; - h = state->height = params->height; - state->wrapping = params->wrapping; - state->completed = FALSE; - state->tiles = snewn(state->width * state->height, unsigned char); - memset(state->tiles, 0, state->width * state->height); - state->barriers = snewn(state->width * state->height, unsigned char); - memset(state->barriers, 0, state->width * state->height); + ret = snew(game_params); + *ret = net_presets[i]; - /* - * Set up border barriers if this is a non-wrapping game. - */ - if (!state->wrapping) { - for (x = 0; x < state->width; x++) { - barrier(state, x, 0) |= U; - barrier(state, x, state->height-1) |= D; - } - for (y = 0; y < state->height; y++) { - barrier(state, y, 0) |= L; - barrier(state, y, state->width-1) |= R; - } + sprintf(str, "%dx%d%s", ret->width, ret->height, + ret->wrapping ? " wrapping" : ""); + + *name = dupstr(str); + *params = ret; + return TRUE; +} + +static void free_params(game_params *params) +{ + sfree(params); +} + +static game_params *dup_params(const game_params *params) +{ + game_params *ret = snew(game_params); + *ret = *params; /* structure copy */ + return ret; +} + +static void decode_params(game_params *ret, char const *string) +{ + char const *p = string; + + ret->width = atoi(p); + while (*p && isdigit((unsigned char)*p)) p++; + if (*p == 'x') { + p++; + ret->height = atoi(p); + while (*p && isdigit((unsigned char)*p)) p++; + } else { + ret->height = ret->width; } - /* - * Seed the internal random number generator. - */ - rs = random_init(seed, strlen(seed)); + while (*p) { + if (*p == 'w') { + p++; + ret->wrapping = TRUE; + } else if (*p == 'b') { + p++; + ret->barrier_probability = (float)atof(p); + while (*p && (*p == '.' || isdigit((unsigned char)*p))) p++; + } else if (*p == 'a') { + p++; + ret->unique = FALSE; + } else + p++; /* skip any other gunk */ + } +} + +static char *encode_params(const game_params *params, int full) +{ + char ret[400]; + int len; + + len = sprintf(ret, "%dx%d", params->width, params->height); + if (params->wrapping) + ret[len++] = 'w'; + if (full && params->barrier_probability) + len += sprintf(ret+len, "b%g", params->barrier_probability); + if (full && !params->unique) + ret[len++] = 'a'; + assert(len < lenof(ret)); + ret[len] = '\0'; + + return dupstr(ret); +} + +static config_item *game_configure(const game_params *params) +{ + config_item *ret; + char buf[80]; + + ret = snewn(6, config_item); + + ret[0].name = "Width"; + ret[0].type = C_STRING; + sprintf(buf, "%d", params->width); + ret[0].sval = dupstr(buf); + ret[0].ival = 0; + + ret[1].name = "Height"; + ret[1].type = C_STRING; + sprintf(buf, "%d", params->height); + ret[1].sval = dupstr(buf); + ret[1].ival = 0; + + ret[2].name = "Walls wrap around"; + ret[2].type = C_BOOLEAN; + ret[2].sval = NULL; + ret[2].ival = params->wrapping; + + ret[3].name = "Barrier probability"; + ret[3].type = C_STRING; + sprintf(buf, "%g", params->barrier_probability); + ret[3].sval = dupstr(buf); + ret[3].ival = 0; + + ret[4].name = "Ensure unique solution"; + ret[4].type = C_BOOLEAN; + ret[4].sval = NULL; + ret[4].ival = params->unique; + + ret[5].name = NULL; + ret[5].type = C_END; + ret[5].sval = NULL; + ret[5].ival = 0; + + return ret; +} + +static game_params *custom_params(const config_item *cfg) +{ + game_params *ret = snew(game_params); + + ret->width = atoi(cfg[0].sval); + ret->height = atoi(cfg[1].sval); + ret->wrapping = cfg[2].ival; + ret->barrier_probability = (float)atof(cfg[3].sval); + ret->unique = cfg[4].ival; + + return ret; +} + +static char *validate_params(const game_params *params, int full) +{ + if (params->width <= 0 || params->height <= 0) + return "Width and height must both be greater than zero"; + if (params->width <= 1 && params->height <= 1) + return "At least one of width and height must be greater than one"; + if (params->barrier_probability < 0) + return "Barrier probability may not be negative"; + if (params->barrier_probability > 1) + return "Barrier probability may not be greater than 1"; /* - * Construct the unshuffled grid. + * Specifying either grid dimension as 2 in a wrapping puzzle + * makes it actually impossible to ensure a unique puzzle + * solution. * - * To do this, we simply start at the centre point, repeatedly - * choose a random possibility out of the available ways to - * extend a used square into an unused one, and do it. After - * extending the third line out of a square, we remove the - * fourth from the possibilities list to avoid any full-cross - * squares (which would make the game too easy because they - * only have one orientation). + * Proof: * - * The slightly worrying thing is the avoidance of full-cross - * squares. Can this cause our unsophisticated construction - * algorithm to paint itself into a corner, by getting into a - * situation where there are some unreached squares and the - * only way to reach any of them is to extend a T-piece into a - * full cross? + * Without loss of generality, let us assume the puzzle _width_ + * is 2, so we can conveniently discuss rows without having to + * say `rows/columns' all the time. (The height may be 2 as + * well, but that doesn't matter.) * - * Answer: no it can't, and here's a proof. + * In each row, there are two edges between tiles: the inner + * edge (running down the centre of the grid) and the outer + * edge (the identified left and right edges of the grid). * - * Any contiguous group of such unreachable squares must be - * surrounded on _all_ sides by T-pieces pointing away from the - * group. (If not, then there is a square which can be extended - * into one of the `unreachable' ones, and so it wasn't - * unreachable after all.) In particular, this implies that - * each contiguous group of unreachable squares must be - * rectangular in shape (any deviation from that yields a - * non-T-piece next to an `unreachable' square). + * Lemma: In any valid 2xn puzzle there must be at least one + * row in which _exactly one_ of the inner edge and outer edge + * is connected. * - * So we have a rectangle of unreachable squares, with T-pieces - * forming a solid border around the rectangle. The corners of - * that border must be connected (since every tile connects all - * the lines arriving in it), and therefore the border must - * form a closed loop around the rectangle. + * Proof: No row can have _both_ inner and outer edges + * connected, because this would yield a loop. So the only + * other way to falsify the lemma is for every row to have + * _neither_ the inner nor outer edge connected. But this + * means there is no connection at all between the left and + * right columns of the puzzle, so there are two disjoint + * subgraphs, which is also disallowed. [] * - * But this can't have happened in the first place, since we - * _know_ we've avoided creating closed loops! Hence, no such - * situation can ever arise, and the naive grid construction - * algorithm will guaranteeably result in a complete grid - * containing no unreached squares, no full crosses _and_ no - * closed loops. [] + * Given such a row, it is always possible to make the + * disconnected edge connected and the connected edge + * disconnected without changing the state of any other edge. + * (This is easily seen by case analysis on the various tiles: + * left-pointing and right-pointing endpoints can be exchanged, + * likewise T-pieces, and a corner piece can select its + * horizontal connectivity independently of its vertical.) This + * yields a distinct valid solution. + * + * Thus, for _every_ row in which exactly one of the inner and + * outer edge is connected, there are two valid states for that + * row, and hence the total number of solutions of the puzzle + * is at least 2^(number of such rows), and in particular is at + * least 2 since there must be at least one such row. [] */ - possibilities = newtree234(xyd_cmp); - add234(possibilities, new_xyd(w/2, h/2, R)); - add234(possibilities, new_xyd(w/2, h/2, U)); - add234(possibilities, new_xyd(w/2, h/2, L)); - add234(possibilities, new_xyd(w/2, h/2, D)); + if (full && params->unique && params->wrapping && + (params->width == 2 || params->height == 2)) + return "No wrapping puzzle with a width or height of 2 can have" + " a unique solution"; - while (count234(possibilities) > 0) { - int i; - struct xyd *xyd; - int x1, y1, d1, x2, y2, d2, d; - - /* - * Extract a randomly chosen possibility from the list. - */ - i = random_upto(rs, count234(possibilities)); - xyd = delpos234(possibilities, i); - x1 = xyd->x; - y1 = xyd->y; - d1 = xyd->direction; - sfree(xyd); + return NULL; +} - OFFSET(x2, y2, x1, y1, d1, state); - d2 = F(d1); -#ifdef DEBUG - printf("picked (%d,%d,%c) <-> (%d,%d,%c)\n", - x1, y1, "0RU3L567D9abcdef"[d1], x2, y2, "0RU3L567D9abcdef"[d2]); -#endif +/* ---------------------------------------------------------------------- + * Solver used to assure solution uniqueness during generation. + */ - /* - * Make the connection. (We should be moving to an as yet - * unused tile.) - */ - tile(state, x1, y1) |= d1; - assert(tile(state, x2, y2) == 0); - tile(state, x2, y2) |= d2; +/* + * Test cases I used while debugging all this were + * + * ./net --generate 1 13x11w#12300 + * which expands under the non-unique grid generation rules to + * 13x11w:5eaade1bd222664436d5e2965c12656b1129dd825219e3274d558d5eb2dab5da18898e571d5a2987be79746bd95726c597447d6da96188c513add829da7681da954db113d3cd244 + * and has two ambiguous areas. + * + * An even better one is + * 13x11w#507896411361192 + * which expands to + * 13x11w:b7125b1aec598eb31bd58d82572bc11494e5dee4e8db2bdd29b88d41a16bdd996d2996ddec8c83741a1e8674e78328ba71737b8894a9271b1cd1399453d1952e43951d9b712822e + * and has an ambiguous area _and_ a situation where loop avoidance + * is a necessary deductive technique. + * + * Then there's + * 48x25w#820543338195187 + * becoming + * 48x25w:255989d14cdd185deaa753a93821a12edc1ab97943ac127e2685d7b8b3c48861b2192416139212b316eddd35de43714ebc7628d753db32e596284d9ec52c5a7dc1b4c811a655117d16dc28921b2b4161352cab1d89d18bc836b8b891d55ea4622a1251861b5bc9a8aa3e5bcd745c95229ca6c3b5e21d5832d397e917325793d7eb442dc351b2db2a52ba8e1651642275842d8871d5534aabc6d5b741aaa2d48ed2a7dbbb3151ddb49d5b9a7ed1ab98ee75d613d656dbba347bc514c84556b43a9bc65a3256ead792488b862a9d2a8a39b4255a4949ed7dbd79443292521265896b4399c95ede89d7c8c797a6a57791a849adea489359a158aa12e5dacce862b8333b7ebea7d344d1a3c53198864b73a9dedde7b663abb1b539e1e8853b1b7edb14a2a17ebaae4dbe63598a2e7e9a2dbdad415bc1d8cb88cbab5a8c82925732cd282e641ea3bd7d2c6e776de9117a26be86deb7c82c89524b122cb9397cd1acd2284e744ea62b9279bae85479ababe315c3ac29c431333395b24e6a1e3c43a2da42d4dce84aadd5b154aea555eaddcbd6e527d228c19388d9b424d94214555a7edbdeebe569d4a56dc51a86bd9963e377bb74752bd5eaa5761ba545e297b62a1bda46ab4aee423ad6c661311783cc18786d4289236563cb4a75ec67d481c14814994464cd1b87396dee63e5ab6e952cc584baa1d4c47cb557ec84dbb63d487c8728118673a166846dd3a4ebc23d6cb9c5827d96b4556e91899db32b517eda815ae271a8911bd745447121dc8d321557bc2a435ebec1bbac35b1a291669451174e6aa2218a4a9c5a6ca31ebc45d84e3a82c121e9ced7d55e9a + * which has a spot (far right) where slightly more complex loop + * avoidance is required. + */ - /* - * If we have created a T-piece, remove its last - * possibility. - */ - if (COUNT(tile(state, x1, y1)) == 3) { - struct xyd xyd1, *xydp; +struct todo { + unsigned char *marked; + int *buffer; + int buflen; + int head, tail; +}; - xyd1.x = x1; - xyd1.y = y1; - xyd1.direction = 0x0F ^ tile(state, x1, y1); +static struct todo *todo_new(int maxsize) +{ + struct todo *todo = snew(struct todo); + todo->marked = snewn(maxsize, unsigned char); + memset(todo->marked, 0, maxsize); + todo->buflen = maxsize + 1; + todo->buffer = snewn(todo->buflen, int); + todo->head = todo->tail = 0; + return todo; +} - xydp = find234(possibilities, &xyd1, NULL); +static void todo_free(struct todo *todo) +{ + sfree(todo->marked); + sfree(todo->buffer); + sfree(todo); +} - if (xydp) { -#ifdef DEBUG - printf("T-piece; removing (%d,%d,%c)\n", - xydp->x, xydp->y, "0RU3L567D9abcdef"[xydp->direction]); -#endif - del234(possibilities, xydp); - sfree(xydp); - } - } +static void todo_add(struct todo *todo, int index) +{ + if (todo->marked[index]) + return; /* already on the list */ + todo->marked[index] = TRUE; + todo->buffer[todo->tail++] = index; + if (todo->tail == todo->buflen) + todo->tail = 0; +} - /* - * Remove all other possibilities that were pointing at the - * tile we've just moved into. - */ - for (d = 1; d < 0x10; d <<= 1) { - int x3, y3, d3; - struct xyd xyd1, *xydp; +static int todo_get(struct todo *todo) { + int ret; - OFFSET(x3, y3, x2, y2, d, state); - d3 = F(d); + if (todo->head == todo->tail) + return -1; /* list is empty */ + ret = todo->buffer[todo->head++]; + if (todo->head == todo->buflen) + todo->head = 0; + todo->marked[ret] = FALSE; - xyd1.x = x3; - xyd1.y = y3; - xyd1.direction = d3; + return ret; +} - xydp = find234(possibilities, &xyd1, NULL); +/* + * Return values: -1 means puzzle was proved inconsistent, 0 means we + * failed to narrow down to a unique solution, +1 means we solved it + * fully. + */ +static int net_solver(int w, int h, unsigned char *tiles, + unsigned char *barriers, int wrapping) +{ + unsigned char *tilestate; + unsigned char *edgestate; + int *deadends; + int *equivalence; + struct todo *todo; + int i, j, x, y; + int area; + int done_something; - if (xydp) { -#ifdef DEBUG - printf("Loop avoidance; removing (%d,%d,%c)\n", - xydp->x, xydp->y, "0RU3L567D9abcdef"[xydp->direction]); -#endif - del234(possibilities, xydp); - sfree(xydp); - } + /* + * Set up the solver's data structures. + */ + + /* + * tilestate stores the possible orientations of each tile. + * There are up to four of these, so we'll index the array in + * fours. tilestate[(y * w + x) * 4] and its three successive + * members give the possible orientations, clearing to 255 from + * the end as things are ruled out. + * + * In this loop we also count up the area of the grid (which is + * not _necessarily_ equal to w*h, because there might be one + * or more blank squares present. This will never happen in a + * grid generated _by_ this program, but it's worth keeping the + * solver as general as possible.) + */ + tilestate = snewn(w * h * 4, unsigned char); + area = 0; + for (i = 0; i < w*h; i++) { + tilestate[i * 4] = tiles[i] & 0xF; + for (j = 1; j < 4; j++) { + if (tilestate[i * 4 + j - 1] == 255 || + A(tilestate[i * 4 + j - 1]) == tilestate[i * 4]) + tilestate[i * 4 + j] = 255; + else + tilestate[i * 4 + j] = A(tilestate[i * 4 + j - 1]); } + if (tiles[i] != 0) + area++; + } - /* - * Add new possibilities to the list for moving _out_ of - * the tile we have just moved into. - */ - for (d = 1; d < 0x10; d <<= 1) { - int x3, y3; - - if (d == d2) - continue; /* we've got this one already */ - - if (!state->wrapping) { - if (d == U && y2 == 0) - continue; - if (d == D && y2 == state->height-1) - continue; - if (d == L && x2 == 0) - continue; - if (d == R && x2 == state->width-1) - continue; - } - - OFFSET(x3, y3, x2, y2, d, state); - - if (tile(state, x3, y3)) - continue; /* this would create a loop */ + /* + * edgestate stores the known state of each edge. It is 0 for + * unknown, 1 for open (connected) and 2 for closed (not + * connected). + * + * In principle we need only worry about each edge once each, + * but in fact it's easier to track each edge twice so that we + * can reference it from either side conveniently. Also I'm + * going to allocate _five_ bytes per tile, rather than the + * obvious four, so that I can index edgestate[(y*w+x) * 5 + d] + * where d is 1,2,4,8 and they never overlap. + */ + edgestate = snewn((w * h - 1) * 5 + 9, unsigned char); + memset(edgestate, 0, (w * h - 1) * 5 + 9); -#ifdef DEBUG - printf("New frontier; adding (%d,%d,%c)\n", - x2, y2, "0RU3L567D9abcdef"[d]); -#endif - add234(possibilities, new_xyd(x2, y2, d)); - } - } - /* Having done that, we should have no possibilities remaining. */ - assert(count234(possibilities) == 0); - freetree234(possibilities); + /* + * deadends tracks which edges have dead ends on them. It is + * indexed by tile and direction: deadends[(y*w+x) * 5 + d] + * tells you whether heading out of tile (x,y) in direction d + * can reach a limited amount of the grid. Values are area+1 + * (no dead end known) or less than that (can reach _at most_ + * this many other tiles by heading this way out of this tile). + */ + deadends = snewn((w * h - 1) * 5 + 9, int); + for (i = 0; i < (w * h - 1) * 5 + 9; i++) + deadends[i] = area+1; /* - * Now compute a list of the possible barrier locations. + * equivalence tracks which sets of tiles are known to be + * connected to one another, so we can avoid creating loops by + * linking together tiles which are already linked through + * another route. + * + * This is a disjoint set forest structure: equivalence[i] + * contains the index of another member of the equivalence + * class containing i, or contains i itself for precisely one + * member in each such class. To find a representative member + * of the equivalence class containing i, you keep replacing i + * with equivalence[i] until it stops changing; then you go + * _back_ along the same path and point everything on it + * directly at the representative member so as to speed up + * future searches. Then you test equivalence between tiles by + * finding the representative of each tile and seeing if + * they're the same; and you create new equivalence (merge + * classes) by finding the representative of each tile and + * setting equivalence[one]=the_other. */ - barriers = newtree234(xyd_cmp); - for (y = 0; y < state->height - (!state->wrapping); y++) { - for (x = 0; x < state->width - (!state->wrapping); x++) { + equivalence = snew_dsf(w * h); - if (!(tile(state, x, y) & R)) - add234(barriers, new_xyd(x, y, R)); - if (!(tile(state, x, y) & D)) - add234(barriers, new_xyd(x, y, D)); + /* + * On a non-wrapping grid, we instantly know that all the edges + * round the edge are closed. + */ + if (!wrapping) { + for (i = 0; i < w; i++) { + edgestate[i * 5 + 2] = edgestate[((h-1) * w + i) * 5 + 8] = 2; + } + for (i = 0; i < h; i++) { + edgestate[(i * w + w-1) * 5 + 1] = edgestate[(i * w) * 5 + 4] = 2; } } /* - * Now shuffle the grid. + * If we have barriers available, we can mark those edges as + * closed too. */ - for (y = 0; y < state->height - (!state->wrapping); y++) { - for (x = 0; x < state->width - (!state->wrapping); x++) { - int orig = tile(state, x, y); - int rot = random_upto(rs, 4); - tile(state, x, y) = ROT(orig, rot); + if (barriers) { + for (y = 0; y < h; y++) for (x = 0; x < w; x++) { + int d; + for (d = 1; d <= 8; d += d) { + if (barriers[y*w+x] & d) { + int x2, y2; + /* + * In principle the barrier list should already + * contain each barrier from each side, but + * let's not take chances with our internal + * consistency. + */ + OFFSETWH(x2, y2, x, y, d, w, h); + edgestate[(y*w+x) * 5 + d] = 2; + edgestate[(y2*w+x2) * 5 + F(d)] = 2; + } + } } } /* - * And now choose barrier locations. (We carefully do this - * _after_ shuffling, so that changing the barrier rate in the - * params while keeping the game seed the same will give the - * same shuffled grid and _only_ change the barrier locations. - * Also the way we choose barrier locations, by repeatedly - * choosing one possibility from the list until we have enough, - * is designed to ensure that raising the barrier rate while - * keeping the seed the same will provide a superset of the - * previous barrier set - i.e. if you ask for 10 barriers, and - * then decide that's still too hard and ask for 20, you'll get - * the original 10 plus 10 more, rather than getting 20 new - * ones and the chance of remembering your first 10.) + * Since most deductions made by this solver are local (the + * exception is loop avoidance, where joining two tiles + * together on one side of the grid can theoretically permit a + * fresh deduction on the other), we can address the scaling + * problem inherent in iterating repeatedly over the entire + * grid by instead working with a to-do list. */ - nbarriers = params->barrier_probability * count234(barriers); - assert(nbarriers >= 0 && nbarriers <= count234(barriers)); + todo = todo_new(w * h); - while (nbarriers > 0) { - int i; - struct xyd *xyd; - int x1, y1, d1, x2, y2, d2; + /* + * Main deductive loop. + */ + done_something = TRUE; /* prevent instant termination! */ + while (1) { + int index; /* - * Extract a randomly chosen barrier from the list. + * Take a tile index off the todo list and process it. */ - i = random_upto(rs, count234(barriers)); - xyd = delpos234(barriers, i); + index = todo_get(todo); + if (index == -1) { + /* + * If we have run out of immediate things to do, we + * have no choice but to scan the whole grid for + * longer-range things we've missed. Hence, I now add + * every square on the grid back on to the to-do list. + * I also set `done_something' to FALSE at this point; + * if we later come back here and find it still FALSE, + * we will know we've scanned the entire grid without + * finding anything new to do, and we can terminate. + */ + if (!done_something) + break; + for (i = 0; i < w*h; i++) + todo_add(todo, i); + done_something = FALSE; - assert(xyd != NULL); + index = todo_get(todo); + } + + y = index / w; + x = index % w; + { + int d, ourclass = dsf_canonify(equivalence, y*w+x); + int deadendmax[9]; + + deadendmax[1] = deadendmax[2] = deadendmax[4] = deadendmax[8] = 0; + + for (i = j = 0; i < 4 && tilestate[(y*w+x) * 4 + i] != 255; i++) { + int valid; + int nnondeadends, nondeadends[4], deadendtotal; + int nequiv, equiv[5]; + int val = tilestate[(y*w+x) * 4 + i]; + + valid = TRUE; + nnondeadends = deadendtotal = 0; + equiv[0] = ourclass; + nequiv = 1; + for (d = 1; d <= 8; d += d) { + /* + * Immediately rule out this orientation if it + * conflicts with any known edge. + */ + if ((edgestate[(y*w+x) * 5 + d] == 1 && !(val & d)) || + (edgestate[(y*w+x) * 5 + d] == 2 && (val & d))) + valid = FALSE; + + if (val & d) { + /* + * Count up the dead-end statistics. + */ + if (deadends[(y*w+x) * 5 + d] <= area) { + deadendtotal += deadends[(y*w+x) * 5 + d]; + } else { + nondeadends[nnondeadends++] = d; + } + + /* + * Ensure we aren't linking to any tiles, + * through edges not already known to be + * open, which create a loop. + */ + if (edgestate[(y*w+x) * 5 + d] == 0) { + int c, k, x2, y2; + + OFFSETWH(x2, y2, x, y, d, w, h); + c = dsf_canonify(equivalence, y2*w+x2); + for (k = 0; k < nequiv; k++) + if (c == equiv[k]) + break; + if (k == nequiv) + equiv[nequiv++] = c; + else + valid = FALSE; + } + } + } + + if (nnondeadends == 0) { + /* + * If this orientation links together dead-ends + * with a total area of less than the entire + * grid, it is invalid. + * + * (We add 1 to deadendtotal because of the + * tile itself, of course; one tile linking + * dead ends of size 2 and 3 forms a subnetwork + * with a total area of 6, not 5.) + */ + if (deadendtotal > 0 && deadendtotal+1 < area) + valid = FALSE; + } else if (nnondeadends == 1) { + /* + * If this orientation links together one or + * more dead-ends with precisely one + * non-dead-end, then we may have to mark that + * non-dead-end as a dead end going the other + * way. However, it depends on whether all + * other orientations share the same property. + */ + deadendtotal++; + if (deadendmax[nondeadends[0]] < deadendtotal) + deadendmax[nondeadends[0]] = deadendtotal; + } else { + /* + * If this orientation links together two or + * more non-dead-ends, then we can rule out the + * possibility of putting in new dead-end + * markings in those directions. + */ + int k; + for (k = 0; k < nnondeadends; k++) + deadendmax[nondeadends[k]] = area+1; + } + + if (valid) + tilestate[(y*w+x) * 4 + j++] = val; +#ifdef SOLVER_DIAGNOSTICS + else + printf("ruling out orientation %x at %d,%d\n", val, x, y); +#endif + } + + if (j == 0) { + /* If we've ruled out all possible orientations for a + * tile, then our puzzle has no solution at all. */ + return -1; + } + + if (j < i) { + done_something = TRUE; + + /* + * We have ruled out at least one tile orientation. + * Make sure the rest are blanked. + */ + while (j < 4) + tilestate[(y*w+x) * 4 + j++] = 255; + } + + /* + * Now go through the tile orientations again and see + * if we've deduced anything new about any edges. + */ + { + int a, o; + a = 0xF; o = 0; + + for (i = 0; i < 4 && tilestate[(y*w+x) * 4 + i] != 255; i++) { + a &= tilestate[(y*w+x) * 4 + i]; + o |= tilestate[(y*w+x) * 4 + i]; + } + for (d = 1; d <= 8; d += d) + if (edgestate[(y*w+x) * 5 + d] == 0) { + int x2, y2, d2; + OFFSETWH(x2, y2, x, y, d, w, h); + d2 = F(d); + if (a & d) { + /* This edge is open in all orientations. */ +#ifdef SOLVER_DIAGNOSTICS + printf("marking edge %d,%d:%d open\n", x, y, d); +#endif + edgestate[(y*w+x) * 5 + d] = 1; + edgestate[(y2*w+x2) * 5 + d2] = 1; + dsf_merge(equivalence, y*w+x, y2*w+x2); + done_something = TRUE; + todo_add(todo, y2*w+x2); + } else if (!(o & d)) { + /* This edge is closed in all orientations. */ +#ifdef SOLVER_DIAGNOSTICS + printf("marking edge %d,%d:%d closed\n", x, y, d); +#endif + edgestate[(y*w+x) * 5 + d] = 2; + edgestate[(y2*w+x2) * 5 + d2] = 2; + done_something = TRUE; + todo_add(todo, y2*w+x2); + } + } + + } + + /* + * Now check the dead-end markers and see if any of + * them has lowered from the real ones. + */ + for (d = 1; d <= 8; d += d) { + int x2, y2, d2; + OFFSETWH(x2, y2, x, y, d, w, h); + d2 = F(d); + if (deadendmax[d] > 0 && + deadends[(y2*w+x2) * 5 + d2] > deadendmax[d]) { +#ifdef SOLVER_DIAGNOSTICS + printf("setting dead end value %d,%d:%d to %d\n", + x2, y2, d2, deadendmax[d]); +#endif + deadends[(y2*w+x2) * 5 + d2] = deadendmax[d]; + done_something = TRUE; + todo_add(todo, y2*w+x2); + } + } + + } + } + + /* + * Mark all completely determined tiles as locked. + */ + j = +1; + for (i = 0; i < w*h; i++) { + if (tilestate[i * 4 + 1] == 255) { + assert(tilestate[i * 4 + 0] != 255); + tiles[i] = tilestate[i * 4] | LOCKED; + } else { + tiles[i] &= ~LOCKED; + j = 0; + } + } + + /* + * Free up working space. + */ + todo_free(todo); + sfree(tilestate); + sfree(edgestate); + sfree(deadends); + sfree(equivalence); + + return j; +} + +/* ---------------------------------------------------------------------- + * Randomly select a new game description. + */ + +/* + * Function to randomly perturb an ambiguous section in a grid, to + * attempt to ensure unique solvability. + */ +static void perturb(int w, int h, unsigned char *tiles, int wrapping, + random_state *rs, int startx, int starty, int startd) +{ + struct xyd *perimeter, *perim2, *loop[2], looppos[2]; + int nperim, perimsize, nloop[2], loopsize[2]; + int x, y, d, i; + + /* + * We know that the tile at (startx,starty) is part of an + * ambiguous section, and we also know that its neighbour in + * direction startd is fully specified. We begin by tracing all + * the way round the ambiguous area. + */ + nperim = perimsize = 0; + perimeter = NULL; + x = startx; + y = starty; + d = startd; +#ifdef PERTURB_DIAGNOSTICS + printf("perturb %d,%d:%d\n", x, y, d); +#endif + do { + int x2, y2, d2; + + if (nperim >= perimsize) { + perimsize = perimsize * 3 / 2 + 32; + perimeter = sresize(perimeter, perimsize, struct xyd); + } + perimeter[nperim].x = x; + perimeter[nperim].y = y; + perimeter[nperim].direction = d; + nperim++; +#ifdef PERTURB_DIAGNOSTICS + printf("perimeter: %d,%d:%d\n", x, y, d); +#endif + + /* + * First, see if we can simply turn left from where we are + * and find another locked square. + */ + d2 = A(d); + OFFSETWH(x2, y2, x, y, d2, w, h); + if ((!wrapping && (abs(x2-x) > 1 || abs(y2-y) > 1)) || + (tiles[y2*w+x2] & LOCKED)) { + d = d2; + } else { + /* + * Failing that, step left into the new square and look + * in front of us. + */ + x = x2; + y = y2; + OFFSETWH(x2, y2, x, y, d, w, h); + if ((wrapping || (abs(x2-x) <= 1 && abs(y2-y) <= 1)) && + !(tiles[y2*w+x2] & LOCKED)) { + /* + * And failing _that_, we're going to have to step + * forward into _that_ square and look right at the + * same locked square as we started with. + */ + x = x2; + y = y2; + d = C(d); + } + } + + } while (x != startx || y != starty || d != startd); + + /* + * Our technique for perturbing this ambiguous area is to + * search round its edge for a join we can make: that is, an + * edge on the perimeter which is (a) not currently connected, + * and (b) connecting it would not yield a full cross on either + * side. Then we make that join, search round the network to + * find the loop thus constructed, and sever the loop at a + * randomly selected other point. + */ + perim2 = snewn(nperim, struct xyd); + memcpy(perim2, perimeter, nperim * sizeof(struct xyd)); + /* Shuffle the perimeter, so as to search it without directional bias. */ + shuffle(perim2, nperim, sizeof(*perim2), rs); + for (i = 0; i < nperim; i++) { + int x2, y2; + + x = perim2[i].x; + y = perim2[i].y; + d = perim2[i].direction; + + OFFSETWH(x2, y2, x, y, d, w, h); + if (!wrapping && (abs(x2-x) > 1 || abs(y2-y) > 1)) + continue; /* can't link across non-wrapping border */ + if (tiles[y*w+x] & d) + continue; /* already linked in this direction! */ + if (((tiles[y*w+x] | d) & 15) == 15) + continue; /* can't turn this tile into a cross */ + if (((tiles[y2*w+x2] | F(d)) & 15) == 15) + continue; /* can't turn other tile into a cross */ + + /* + * We've found the point at which we're going to make a new + * link. + */ +#ifdef PERTURB_DIAGNOSTICS + printf("linking %d,%d:%d\n", x, y, d); +#endif + tiles[y*w+x] |= d; + tiles[y2*w+x2] |= F(d); + + break; + } + sfree(perim2); + + if (i == nperim) { + sfree(perimeter); + return; /* nothing we can do! */ + } + + /* + * Now we've constructed a new link, we need to find the entire + * loop of which it is a part. + * + * In principle, this involves doing a complete search round + * the network. However, I anticipate that in the vast majority + * of cases the loop will be quite small, so what I'm going to + * do is make _two_ searches round the network in parallel, one + * keeping its metaphorical hand on the left-hand wall while + * the other keeps its hand on the right. As soon as one of + * them gets back to its starting point, I abandon the other. + */ + for (i = 0; i < 2; i++) { + loopsize[i] = nloop[i] = 0; + loop[i] = NULL; + looppos[i].x = x; + looppos[i].y = y; + looppos[i].direction = d; + } + while (1) { + for (i = 0; i < 2; i++) { + int x2, y2, j; + + x = looppos[i].x; + y = looppos[i].y; + d = looppos[i].direction; + + OFFSETWH(x2, y2, x, y, d, w, h); + + /* + * Add this path segment to the loop, unless it exactly + * reverses the previous one on the loop in which case + * we take it away again. + */ +#ifdef PERTURB_DIAGNOSTICS + printf("looppos[%d] = %d,%d:%d\n", i, x, y, d); +#endif + if (nloop[i] > 0 && + loop[i][nloop[i]-1].x == x2 && + loop[i][nloop[i]-1].y == y2 && + loop[i][nloop[i]-1].direction == F(d)) { +#ifdef PERTURB_DIAGNOSTICS + printf("removing path segment %d,%d:%d from loop[%d]\n", + x2, y2, F(d), i); +#endif + nloop[i]--; + } else { + if (nloop[i] >= loopsize[i]) { + loopsize[i] = loopsize[i] * 3 / 2 + 32; + loop[i] = sresize(loop[i], loopsize[i], struct xyd); + } +#ifdef PERTURB_DIAGNOSTICS + printf("adding path segment %d,%d:%d to loop[%d]\n", + x, y, d, i); +#endif + loop[i][nloop[i]++] = looppos[i]; + } + +#ifdef PERTURB_DIAGNOSTICS + printf("tile at new location is %x\n", tiles[y2*w+x2] & 0xF); +#endif + d = F(d); + for (j = 0; j < 4; j++) { + if (i == 0) + d = A(d); + else + d = C(d); +#ifdef PERTURB_DIAGNOSTICS + printf("trying dir %d\n", d); +#endif + if (tiles[y2*w+x2] & d) { + looppos[i].x = x2; + looppos[i].y = y2; + looppos[i].direction = d; + break; + } + } + + assert(j < 4); + assert(nloop[i] > 0); + + if (looppos[i].x == loop[i][0].x && + looppos[i].y == loop[i][0].y && + looppos[i].direction == loop[i][0].direction) { +#ifdef PERTURB_DIAGNOSTICS + printf("loop %d finished tracking\n", i); +#endif + + /* + * Having found our loop, we now sever it at a + * randomly chosen point - absolutely any will do - + * which is not the one we joined it at to begin + * with. Conveniently, the one we joined it at is + * loop[i][0], so we just avoid that one. + */ + j = random_upto(rs, nloop[i]-1) + 1; + x = loop[i][j].x; + y = loop[i][j].y; + d = loop[i][j].direction; + OFFSETWH(x2, y2, x, y, d, w, h); + tiles[y*w+x] &= ~d; + tiles[y2*w+x2] &= ~F(d); + + break; + } + } + if (i < 2) + break; + } + sfree(loop[0]); + sfree(loop[1]); + + /* + * Finally, we must mark the entire disputed section as locked, + * to prevent the perturb function being called on it multiple + * times. + * + * To do this, we _sort_ the perimeter of the area. The + * existing xyd_cmp function will arrange things into columns + * for us, in such a way that each column has the edges in + * vertical order. Then we can work down each column and fill + * in all the squares between an up edge and a down edge. + */ + qsort(perimeter, nperim, sizeof(struct xyd), xyd_cmp); + x = y = -1; + for (i = 0; i <= nperim; i++) { + if (i == nperim || perimeter[i].x > x) { + /* + * Fill in everything from the last Up edge to the + * bottom of the grid, if necessary. + */ + if (x != -1) { + while (y < h) { +#ifdef PERTURB_DIAGNOSTICS + printf("resolved: locking tile %d,%d\n", x, y); +#endif + tiles[y * w + x] |= LOCKED; + y++; + } + x = y = -1; + } + + if (i == nperim) + break; + + x = perimeter[i].x; + y = 0; + } + + if (perimeter[i].direction == U) { + x = perimeter[i].x; + y = perimeter[i].y; + } else if (perimeter[i].direction == D) { + /* + * Fill in everything from the last Up edge to here. + */ + assert(x == perimeter[i].x && y <= perimeter[i].y); + while (y <= perimeter[i].y) { +#ifdef PERTURB_DIAGNOSTICS + printf("resolved: locking tile %d,%d\n", x, y); +#endif + tiles[y * w + x] |= LOCKED; + y++; + } + x = y = -1; + } + } + + sfree(perimeter); +} + +static int *compute_loops_inner(int w, int h, int wrapping, + const unsigned char *tiles, + const unsigned char *barriers); + +static char *new_game_desc(const game_params *params, random_state *rs, + char **aux, int interactive) +{ + tree234 *possibilities, *barriertree; + int w, h, x, y, cx, cy, nbarriers; + unsigned char *tiles, *barriers; + char *desc, *p; + + w = params->width; + h = params->height; + + cx = w / 2; + cy = h / 2; + + tiles = snewn(w * h, unsigned char); + barriers = snewn(w * h, unsigned char); + + begin_generation: + + memset(tiles, 0, w * h); + memset(barriers, 0, w * h); + + /* + * Construct the unshuffled grid. + * + * To do this, we simply start at the centre point, repeatedly + * choose a random possibility out of the available ways to + * extend a used square into an unused one, and do it. After + * extending the third line out of a square, we remove the + * fourth from the possibilities list to avoid any full-cross + * squares (which would make the game too easy because they + * only have one orientation). + * + * The slightly worrying thing is the avoidance of full-cross + * squares. Can this cause our unsophisticated construction + * algorithm to paint itself into a corner, by getting into a + * situation where there are some unreached squares and the + * only way to reach any of them is to extend a T-piece into a + * full cross? + * + * Answer: no it can't, and here's a proof. + * + * Any contiguous group of such unreachable squares must be + * surrounded on _all_ sides by T-pieces pointing away from the + * group. (If not, then there is a square which can be extended + * into one of the `unreachable' ones, and so it wasn't + * unreachable after all.) In particular, this implies that + * each contiguous group of unreachable squares must be + * rectangular in shape (any deviation from that yields a + * non-T-piece next to an `unreachable' square). + * + * So we have a rectangle of unreachable squares, with T-pieces + * forming a solid border around the rectangle. The corners of + * that border must be connected (since every tile connects all + * the lines arriving in it), and therefore the border must + * form a closed loop around the rectangle. + * + * But this can't have happened in the first place, since we + * _know_ we've avoided creating closed loops! Hence, no such + * situation can ever arise, and the naive grid construction + * algorithm will guaranteeably result in a complete grid + * containing no unreached squares, no full crosses _and_ no + * closed loops. [] + */ + possibilities = newtree234(xyd_cmp_nc); + + if (cx+1 < w) + add234(possibilities, new_xyd(cx, cy, R)); + if (cy-1 >= 0) + add234(possibilities, new_xyd(cx, cy, U)); + if (cx-1 >= 0) + add234(possibilities, new_xyd(cx, cy, L)); + if (cy+1 < h) + add234(possibilities, new_xyd(cx, cy, D)); + + while (count234(possibilities) > 0) { + int i; + struct xyd *xyd; + int x1, y1, d1, x2, y2, d2, d; + + /* + * Extract a randomly chosen possibility from the list. + */ + i = random_upto(rs, count234(possibilities)); + xyd = delpos234(possibilities, i); + x1 = xyd->x; + y1 = xyd->y; + d1 = xyd->direction; + sfree(xyd); + + OFFSET(x2, y2, x1, y1, d1, params); + d2 = F(d1); +#ifdef GENERATION_DIAGNOSTICS + printf("picked (%d,%d,%c) <-> (%d,%d,%c)\n", + x1, y1, "0RU3L567D9abcdef"[d1], x2, y2, "0RU3L567D9abcdef"[d2]); +#endif + + /* + * Make the connection. (We should be moving to an as yet + * unused tile.) + */ + index(params, tiles, x1, y1) |= d1; + assert(index(params, tiles, x2, y2) == 0); + index(params, tiles, x2, y2) |= d2; + + /* + * If we have created a T-piece, remove its last + * possibility. + */ + if (COUNT(index(params, tiles, x1, y1)) == 3) { + struct xyd xyd1, *xydp; + + xyd1.x = x1; + xyd1.y = y1; + xyd1.direction = 0x0F ^ index(params, tiles, x1, y1); + + xydp = find234(possibilities, &xyd1, NULL); + + if (xydp) { +#ifdef GENERATION_DIAGNOSTICS + printf("T-piece; removing (%d,%d,%c)\n", + xydp->x, xydp->y, "0RU3L567D9abcdef"[xydp->direction]); +#endif + del234(possibilities, xydp); + sfree(xydp); + } + } + + /* + * Remove all other possibilities that were pointing at the + * tile we've just moved into. + */ + for (d = 1; d < 0x10; d <<= 1) { + int x3, y3, d3; + struct xyd xyd1, *xydp; + + OFFSET(x3, y3, x2, y2, d, params); + d3 = F(d); + + xyd1.x = x3; + xyd1.y = y3; + xyd1.direction = d3; + + xydp = find234(possibilities, &xyd1, NULL); + + if (xydp) { +#ifdef GENERATION_DIAGNOSTICS + printf("Loop avoidance; removing (%d,%d,%c)\n", + xydp->x, xydp->y, "0RU3L567D9abcdef"[xydp->direction]); +#endif + del234(possibilities, xydp); + sfree(xydp); + } + } + + /* + * Add new possibilities to the list for moving _out_ of + * the tile we have just moved into. + */ + for (d = 1; d < 0x10; d <<= 1) { + int x3, y3; + + if (d == d2) + continue; /* we've got this one already */ + + if (!params->wrapping) { + if (d == U && y2 == 0) + continue; + if (d == D && y2 == h-1) + continue; + if (d == L && x2 == 0) + continue; + if (d == R && x2 == w-1) + continue; + } + + OFFSET(x3, y3, x2, y2, d, params); + + if (index(params, tiles, x3, y3)) + continue; /* this would create a loop */ + +#ifdef GENERATION_DIAGNOSTICS + printf("New frontier; adding (%d,%d,%c)\n", + x2, y2, "0RU3L567D9abcdef"[d]); +#endif + add234(possibilities, new_xyd(x2, y2, d)); + } + } + /* Having done that, we should have no possibilities remaining. */ + assert(count234(possibilities) == 0); + freetree234(possibilities); + + if (params->unique) { + int prevn = -1; + + /* + * Run the solver to check unique solubility. + */ + while (net_solver(w, h, tiles, NULL, params->wrapping) != 1) { + int n = 0; + + /* + * We expect (in most cases) that most of the grid will + * be uniquely specified already, and the remaining + * ambiguous sections will be small and separate. So + * our strategy is to find each individual such + * section, and perform a perturbation on the network + * in that area. + */ + for (y = 0; y < h; y++) for (x = 0; x < w; x++) { + if (x+1 < w && ((tiles[y*w+x] ^ tiles[y*w+x+1]) & LOCKED)) { + n++; + if (tiles[y*w+x] & LOCKED) + perturb(w, h, tiles, params->wrapping, rs, x+1, y, L); + else + perturb(w, h, tiles, params->wrapping, rs, x, y, R); + } + if (y+1 < h && ((tiles[y*w+x] ^ tiles[(y+1)*w+x]) & LOCKED)) { + n++; + if (tiles[y*w+x] & LOCKED) + perturb(w, h, tiles, params->wrapping, rs, x, y+1, U); + else + perturb(w, h, tiles, params->wrapping, rs, x, y, D); + } + } + + /* + * Now n counts the number of ambiguous sections we + * have fiddled with. If we haven't managed to decrease + * it from the last time we ran the solver, give up and + * regenerate the entire grid. + */ + if (prevn != -1 && prevn <= n) + goto begin_generation; /* (sorry) */ + + prevn = n; + } + + /* + * The solver will have left a lot of LOCKED bits lying + * around in the tiles array. Remove them. + */ + for (x = 0; x < w*h; x++) + tiles[x] &= ~LOCKED; + } + + /* + * Now compute a list of the possible barrier locations. + */ + barriertree = newtree234(xyd_cmp_nc); + for (y = 0; y < h; y++) { + for (x = 0; x < w; x++) { + + if (!(index(params, tiles, x, y) & R) && + (params->wrapping || x < w-1)) + add234(barriertree, new_xyd(x, y, R)); + if (!(index(params, tiles, x, y) & D) && + (params->wrapping || y < h-1)) + add234(barriertree, new_xyd(x, y, D)); + } + } + + /* + * Save the unshuffled grid in aux. + */ + { + char *solution; + int i; + + solution = snewn(w * h + 1, char); + for (i = 0; i < w * h; i++) + solution[i] = "0123456789abcdef"[tiles[i] & 0xF]; + solution[w*h] = '\0'; + + *aux = solution; + } + + /* + * Now shuffle the grid. + * + * In order to avoid accidentally generating an already-solved + * grid, we will reshuffle as necessary to ensure that at least + * one edge has a mismatched connection. + * + * This can always be done, since validate_params() enforces a + * grid area of at least 2 and our generator never creates + * either type of rotationally invariant tile (cross and + * blank). Hence there must be at least one edge separating + * distinct tiles, and it must be possible to find orientations + * of those tiles such that one tile is trying to connect + * through that edge and the other is not. + * + * (We could be more subtle, and allow the shuffle to generate + * a grid in which all tiles match up locally and the only + * criterion preventing the grid from being already solved is + * connectedness. However, that would take more effort, and + * it's easier to simply make sure every grid is _obviously_ + * not solved.) + * + * We also require that our shuffle produces no loops in the + * initial grid state, because it's a bit rude to light up a 'HEY, + * YOU DID SOMETHING WRONG!' indicator when the user hasn't even + * had a chance to do _anything_ yet. This also is possible just + * by retrying the whole shuffle on failure, because it's clear + * that at least one non-solved shuffle with no loops must exist. + * (Proof: take the _solved_ state of the puzzle, and rotate one + * endpoint.) + */ + while (1) { + int mismatches, prev_loopsquares, this_loopsquares, i; + int *loops; + + shuffle: + for (y = 0; y < h; y++) { + for (x = 0; x < w; x++) { + int orig = index(params, tiles, x, y); + int rot = random_upto(rs, 4); + index(params, tiles, x, y) = ROT(orig, rot); + } + } + + /* + * Check for loops, and try to fix them by reshuffling just + * the squares involved. + */ + prev_loopsquares = w*h+1; + while (1) { + loops = compute_loops_inner(w, h, params->wrapping, tiles, NULL); + this_loopsquares = 0; + for (i = 0; i < w*h; i++) { + if (loops[i]) { + int orig = tiles[i]; + int rot = random_upto(rs, 4); + tiles[i] = ROT(orig, rot); + this_loopsquares++; + } + } + sfree(loops); + if (this_loopsquares > prev_loopsquares) { + /* + * We're increasing rather than reducing the number of + * loops. Give up and go back to the full shuffle. + */ + goto shuffle; + } + if (this_loopsquares == 0) + break; + prev_loopsquares = this_loopsquares; + } + + mismatches = 0; + /* + * I can't even be bothered to check for mismatches across + * a wrapping edge, so I'm just going to enforce that there + * must be a mismatch across a non-wrapping edge, which is + * still always possible. + */ + for (y = 0; y < h; y++) for (x = 0; x < w; x++) { + if (x+1 < w && ((ROT(index(params, tiles, x, y), 2) ^ + index(params, tiles, x+1, y)) & L)) + mismatches++; + if (y+1 < h && ((ROT(index(params, tiles, x, y), 2) ^ + index(params, tiles, x, y+1)) & U)) + mismatches++; + } + + if (mismatches == 0) + continue; + + /* OK. */ + break; + } + + /* + * And now choose barrier locations. (We carefully do this + * _after_ shuffling, so that changing the barrier rate in the + * params while keeping the random seed the same will give the + * same shuffled grid and _only_ change the barrier locations. + * Also the way we choose barrier locations, by repeatedly + * choosing one possibility from the list until we have enough, + * is designed to ensure that raising the barrier rate while + * keeping the seed the same will provide a superset of the + * previous barrier set - i.e. if you ask for 10 barriers, and + * then decide that's still too hard and ask for 20, you'll get + * the original 10 plus 10 more, rather than getting 20 new + * ones and the chance of remembering your first 10.) + */ + nbarriers = (int)(params->barrier_probability * count234(barriertree)); + assert(nbarriers >= 0 && nbarriers <= count234(barriertree)); + + while (nbarriers > 0) { + int i; + struct xyd *xyd; + int x1, y1, d1, x2, y2, d2; + + /* + * Extract a randomly chosen barrier from the list. + */ + i = random_upto(rs, count234(barriertree)); + xyd = delpos234(barriertree, i); + + assert(xyd != NULL); x1 = xyd->x; y1 = xyd->y; d1 = xyd->direction; sfree(xyd); - OFFSET(x2, y2, x1, y1, d1, state); - d2 = F(d1); + OFFSET(x2, y2, x1, y1, d1, params); + d2 = F(d1); + + index(params, barriers, x1, y1) |= d1; + index(params, barriers, x2, y2) |= d2; + + nbarriers--; + } + + /* + * Clean up the rest of the barrier list. + */ + { + struct xyd *xyd; + + while ( (xyd = delpos234(barriertree, 0)) != NULL) + sfree(xyd); + + freetree234(barriertree); + } + + /* + * Finally, encode the grid into a string game description. + * + * My syntax is extremely simple: each square is encoded as a + * hex digit in which bit 0 means a connection on the right, + * bit 1 means up, bit 2 left and bit 3 down. (i.e. the same + * encoding as used internally). Each digit is followed by + * optional barrier indicators: `v' means a vertical barrier to + * the right of it, and `h' means a horizontal barrier below + * it. + */ + desc = snewn(w * h * 3 + 1, char); + p = desc; + for (y = 0; y < h; y++) { + for (x = 0; x < w; x++) { + *p++ = "0123456789abcdef"[index(params, tiles, x, y)]; + if ((params->wrapping || x < w-1) && + (index(params, barriers, x, y) & R)) + *p++ = 'v'; + if ((params->wrapping || y < h-1) && + (index(params, barriers, x, y) & D)) + *p++ = 'h'; + } + } + assert(p - desc <= w*h*3); + *p = '\0'; + + sfree(tiles); + sfree(barriers); + + return desc; +} + +static char *validate_desc(const game_params *params, const char *desc) +{ + int w = params->width, h = params->height; + int i; + + for (i = 0; i < w*h; i++) { + if (*desc >= '0' && *desc <= '9') + /* OK */; + else if (*desc >= 'a' && *desc <= 'f') + /* OK */; + else if (*desc >= 'A' && *desc <= 'F') + /* OK */; + else if (!*desc) + return "Game description shorter than expected"; + else + return "Game description contained unexpected character"; + desc++; + while (*desc == 'h' || *desc == 'v') + desc++; + } + if (*desc) + return "Game description longer than expected"; + + return NULL; +} + +/* ---------------------------------------------------------------------- + * Construct an initial game state, given a description and parameters. + */ + +static game_state *new_game(midend *me, const game_params *params, + const char *desc) +{ + game_state *state; + int w, h, x, y; + + assert(params->width > 0 && params->height > 0); + assert(params->width > 1 || params->height > 1); + + /* + * Create a blank game state. + */ + state = snew(game_state); + w = state->width = params->width; + h = state->height = params->height; + state->wrapping = params->wrapping; + state->last_rotate_dir = state->last_rotate_x = state->last_rotate_y = 0; + state->completed = state->used_solve = FALSE; + state->tiles = snewn(state->width * state->height, unsigned char); + memset(state->tiles, 0, state->width * state->height); + state->barriers = snewn(state->width * state->height, unsigned char); + memset(state->barriers, 0, state->width * state->height); + + /* + * Parse the game description into the grid. + */ + for (y = 0; y < h; y++) { + for (x = 0; x < w; x++) { + if (*desc >= '0' && *desc <= '9') + tile(state, x, y) = *desc - '0'; + else if (*desc >= 'a' && *desc <= 'f') + tile(state, x, y) = *desc - 'a' + 10; + else if (*desc >= 'A' && *desc <= 'F') + tile(state, x, y) = *desc - 'A' + 10; + if (*desc) + desc++; + while (*desc == 'h' || *desc == 'v') { + int x2, y2, d1, d2; + if (*desc == 'v') + d1 = R; + else + d1 = D; + + OFFSET(x2, y2, x, y, d1, state); + d2 = F(d1); + + barrier(state, x, y) |= d1; + barrier(state, x2, y2) |= d2; + + desc++; + } + } + } + + /* + * Set up border barriers if this is a non-wrapping game. + */ + if (!state->wrapping) { + for (x = 0; x < state->width; x++) { + barrier(state, x, 0) |= U; + barrier(state, x, state->height-1) |= D; + } + for (y = 0; y < state->height; y++) { + barrier(state, 0, y) |= L; + barrier(state, state->width-1, y) |= R; + } + } else { + /* + * We check whether this is de-facto a non-wrapping game + * despite the parameters, in case we were passed the + * description of a non-wrapping game. This is so that we + * can change some aspects of the UI behaviour. + */ + state->wrapping = FALSE; + for (x = 0; x < state->width; x++) + if (!(barrier(state, x, 0) & U) || + !(barrier(state, x, state->height-1) & D)) + state->wrapping = TRUE; + for (y = 0; y < state->height; y++) + if (!(barrier(state, 0, y) & L) || + !(barrier(state, state->width-1, y) & R)) + state->wrapping = TRUE; + } + + return state; +} + +static game_state *dup_game(const game_state *state) +{ + game_state *ret; + + ret = snew(game_state); + ret->width = state->width; + ret->height = state->height; + ret->wrapping = state->wrapping; + ret->completed = state->completed; + ret->used_solve = state->used_solve; + ret->last_rotate_dir = state->last_rotate_dir; + ret->last_rotate_x = state->last_rotate_x; + ret->last_rotate_y = state->last_rotate_y; + ret->tiles = snewn(state->width * state->height, unsigned char); + memcpy(ret->tiles, state->tiles, state->width * state->height); + ret->barriers = snewn(state->width * state->height, unsigned char); + memcpy(ret->barriers, state->barriers, state->width * state->height); + + return ret; +} + +static void free_game(game_state *state) +{ + sfree(state->tiles); + sfree(state->barriers); + sfree(state); +} + +static char *solve_game(const game_state *state, const game_state *currstate, + const char *aux, char **error) +{ + unsigned char *tiles; + char *ret; + int retlen, retsize; + int i; + + tiles = snewn(state->width * state->height, unsigned char); + + if (!aux) { + /* + * Run the internal solver on the provided grid. This might + * not yield a complete solution. + */ + int solver_result; + + memcpy(tiles, state->tiles, state->width * state->height); + solver_result = net_solver(state->width, state->height, tiles, + state->barriers, state->wrapping); + + if (solver_result < 0) { + *error = "No solution exists for this puzzle"; + sfree(tiles); + return NULL; + } + } else { + for (i = 0; i < state->width * state->height; i++) { + int c = aux[i]; + + if (c >= '0' && c <= '9') + tiles[i] = c - '0'; + else if (c >= 'a' && c <= 'f') + tiles[i] = c - 'a' + 10; + else if (c >= 'A' && c <= 'F') + tiles[i] = c - 'A' + 10; + + tiles[i] |= LOCKED; + } + } + + /* + * Now construct a string which can be passed to execute_move() + * to transform the current grid into the solved one. + */ + retsize = 256; + ret = snewn(retsize, char); + retlen = 0; + ret[retlen++] = 'S'; + + for (i = 0; i < state->width * state->height; i++) { + int from = currstate->tiles[i], to = tiles[i]; + int ft = from & (R|L|U|D), tt = to & (R|L|U|D); + int x = i % state->width, y = i / state->width; + int chr = '\0'; + char buf[80], *p = buf; + + if (from == to) + continue; /* nothing needs doing at all */ + + /* + * To transform this tile into the desired tile: first + * unlock the tile if it's locked, then rotate it if + * necessary, then lock it if necessary. + */ + if (from & LOCKED) + p += sprintf(p, ";L%d,%d", x, y); + + if (tt == A(ft)) + chr = 'A'; + else if (tt == C(ft)) + chr = 'C'; + else if (tt == F(ft)) + chr = 'F'; + else { + assert(tt == ft); + chr = '\0'; + } + if (chr) + p += sprintf(p, ";%c%d,%d", chr, x, y); + + if (to & LOCKED) + p += sprintf(p, ";L%d,%d", x, y); + + if (p > buf) { + if (retlen + (p - buf) >= retsize) { + retsize = retlen + (p - buf) + 512; + ret = sresize(ret, retsize, char); + } + memcpy(ret+retlen, buf, p - buf); + retlen += p - buf; + } + } + + assert(retlen < retsize); + ret[retlen] = '\0'; + ret = sresize(ret, retlen+1, char); + + sfree(tiles); + + return ret; +} + +static int game_can_format_as_text_now(const game_params *params) +{ + return TRUE; +} + +static char *game_text_format(const game_state *state) +{ + return NULL; +} + +/* ---------------------------------------------------------------------- + * Utility routine. + */ + +/* + * Compute which squares are reachable from the centre square, as a + * quick visual aid to determining how close the game is to + * completion. This is also a simple way to tell if the game _is_ + * completed - just call this function and see whether every square + * is marked active. + */ +static unsigned char *compute_active(const game_state *state, int cx, int cy) +{ + unsigned char *active; + tree234 *todo; + struct xyd *xyd; + + active = snewn(state->width * state->height, unsigned char); + memset(active, 0, state->width * state->height); + + /* + * We only store (x,y) pairs in todo, but it's easier to reuse + * xyd_cmp and just store direction 0 every time. + */ + todo = newtree234(xyd_cmp_nc); + index(state, active, cx, cy) = ACTIVE; + add234(todo, new_xyd(cx, cy, 0)); + + while ( (xyd = delpos234(todo, 0)) != NULL) { + int x1, y1, d1, x2, y2, d2; + + x1 = xyd->x; + y1 = xyd->y; + sfree(xyd); + + for (d1 = 1; d1 < 0x10; d1 <<= 1) { + OFFSET(x2, y2, x1, y1, d1, state); + d2 = F(d1); + + /* + * If the next tile in this direction is connected to + * us, and there isn't a barrier in the way, and it + * isn't already marked active, then mark it active and + * add it to the to-examine list. + */ + if ((tile(state, x1, y1) & d1) && + (tile(state, x2, y2) & d2) && + !(barrier(state, x1, y1) & d1) && + !index(state, active, x2, y2)) { + index(state, active, x2, y2) = ACTIVE; + add234(todo, new_xyd(x2, y2, 0)); + } + } + } + /* Now we expect the todo list to have shrunk to zero size. */ + assert(count234(todo) == 0); + freetree234(todo); + + return active; +} + +struct net_neighbour_ctx { + int w, h; + const unsigned char *tiles, *barriers; + int i, n, neighbours[4]; +}; +static int net_neighbour(int vertex, void *vctx) +{ + struct net_neighbour_ctx *ctx = (struct net_neighbour_ctx *)vctx; + + if (vertex >= 0) { + int x = vertex % ctx->w, y = vertex / ctx->w; + int tile, dir, x1, y1, v1; + + ctx->i = ctx->n = 0; + + tile = ctx->tiles[vertex]; + if (ctx->barriers) + tile &= ~ctx->barriers[vertex]; + + for (dir = 1; dir < 0x10; dir <<= 1) { + if (!(tile & dir)) + continue; + OFFSETWH(x1, y1, x, y, dir, ctx->w, ctx->h); + v1 = y1 * ctx->w + x1; + if (ctx->tiles[v1] & F(dir)) + ctx->neighbours[ctx->n++] = v1; + } + } + + if (ctx->i < ctx->n) + return ctx->neighbours[ctx->i++]; + else + return -1; +} + +static int *compute_loops_inner(int w, int h, int wrapping, + const unsigned char *tiles, + const unsigned char *barriers) +{ + struct net_neighbour_ctx ctx; + struct findloopstate *fls; + int *loops; + int x, y; + + fls = findloop_new_state(w*h); + ctx.w = w; + ctx.h = h; + ctx.tiles = tiles; + ctx.barriers = barriers; + findloop_run(fls, w*h, net_neighbour, &ctx); + + loops = snewn(w*h, int); + + for (y = 0; y < h; y++) { + for (x = 0; x < w; x++) { + int x1, y1, dir; + int flags = 0; + + for (dir = 1; dir < 0x10; dir <<= 1) { + if ((tiles[y*w+x] & dir) && + !(barriers && (barriers[y*w+x] & dir))) { + OFFSETWH(x1, y1, x, y, dir, w, h); + if ((tiles[y1*w+x1] & F(dir)) && + findloop_is_loop_edge(fls, y*w+x, y1*w+x1)) + flags |= LOOP(dir); + } + } + loops[y*w+x] = flags; + } + } + + findloop_free_state(fls); + return loops; +} + +static int *compute_loops(const game_state *state) +{ + return compute_loops_inner(state->width, state->height, state->wrapping, + state->tiles, state->barriers); +} + +struct game_ui { + int org_x, org_y; /* origin */ + int cx, cy; /* source tile (game coordinates) */ + int cur_x, cur_y; + int cur_visible; + random_state *rs; /* used for jumbling */ +#ifdef USE_DRAGGING + int dragtilex, dragtiley, dragstartx, dragstarty, dragged; +#endif +}; + +static game_ui *new_ui(const game_state *state) +{ + void *seed; + int seedsize; + game_ui *ui = snew(game_ui); + ui->org_x = ui->org_y = 0; + ui->cur_x = ui->cx = state->width / 2; + ui->cur_y = ui->cy = state->height / 2; + ui->cur_visible = FALSE; + get_random_seed(&seed, &seedsize); + ui->rs = random_new(seed, seedsize); + sfree(seed); + + return ui; +} + +static void free_ui(game_ui *ui) +{ + random_free(ui->rs); + sfree(ui); +} + +static char *encode_ui(const game_ui *ui) +{ + char buf[120]; + /* + * We preserve the origin and centre-point coordinates over a + * serialise. + */ + sprintf(buf, "O%d,%d;C%d,%d", ui->org_x, ui->org_y, ui->cx, ui->cy); + return dupstr(buf); +} + +static void decode_ui(game_ui *ui, const char *encoding) +{ + sscanf(encoding, "O%d,%d;C%d,%d", + &ui->org_x, &ui->org_y, &ui->cx, &ui->cy); +} + +static void game_changed_state(game_ui *ui, const game_state *oldstate, + const game_state *newstate) +{ +} + +struct game_drawstate { + int started; + int width, height; + int org_x, org_y; + int tilesize; + int *visible; +}; + +/* ---------------------------------------------------------------------- + * Process a move. + */ +static char *interpret_move(const game_state *state, game_ui *ui, + const game_drawstate *ds, + int x, int y, int button) +{ + char *nullret; + int tx = -1, ty = -1, dir = 0; + int shift = button & MOD_SHFT, ctrl = button & MOD_CTRL; + enum { + NONE, ROTATE_LEFT, ROTATE_180, ROTATE_RIGHT, TOGGLE_LOCK, JUMBLE, + MOVE_ORIGIN, MOVE_SOURCE, MOVE_ORIGIN_AND_SOURCE, MOVE_CURSOR + } action; + + button &= ~MOD_MASK; + nullret = NULL; + action = NONE; + + if (button == LEFT_BUTTON || + button == MIDDLE_BUTTON || +#ifdef USE_DRAGGING + button == LEFT_DRAG || + button == LEFT_RELEASE || + button == RIGHT_DRAG || + button == RIGHT_RELEASE || +#endif + button == RIGHT_BUTTON) { + + if (ui->cur_visible) { + ui->cur_visible = FALSE; + nullret = ""; + } + + /* + * The button must have been clicked on a valid tile. + */ + x -= WINDOW_OFFSET + TILE_BORDER; + y -= WINDOW_OFFSET + TILE_BORDER; + if (x < 0 || y < 0) + return nullret; + tx = x / TILE_SIZE; + ty = y / TILE_SIZE; + if (tx >= state->width || ty >= state->height) + return nullret; + /* Transform from physical to game coords */ + tx = (tx + ui->org_x) % state->width; + ty = (ty + ui->org_y) % state->height; + if (x % TILE_SIZE >= TILE_SIZE - TILE_BORDER || + y % TILE_SIZE >= TILE_SIZE - TILE_BORDER) + return nullret; + +#ifdef USE_DRAGGING + + if (button == MIDDLE_BUTTON +#ifdef STYLUS_BASED + || button == RIGHT_BUTTON /* with a stylus, `right-click' locks */ +#endif + ) { + /* + * Middle button never drags: it only toggles the lock. + */ + action = TOGGLE_LOCK; + } else if (button == LEFT_BUTTON +#ifndef STYLUS_BASED + || button == RIGHT_BUTTON /* (see above) */ +#endif + ) { + /* + * Otherwise, we note down the start point for a drag. + */ + ui->dragtilex = tx; + ui->dragtiley = ty; + ui->dragstartx = x % TILE_SIZE; + ui->dragstarty = y % TILE_SIZE; + ui->dragged = FALSE; + return nullret; /* no actual action */ + } else if (button == LEFT_DRAG +#ifndef STYLUS_BASED + || button == RIGHT_DRAG +#endif + ) { + /* + * Find the new drag point and see if it necessitates a + * rotation. + */ + int x0,y0, xA,yA, xC,yC, xF,yF; + int mx, my; + int d0, dA, dC, dF, dmin; + + tx = ui->dragtilex; + ty = ui->dragtiley; + + mx = x - (ui->dragtilex * TILE_SIZE); + my = y - (ui->dragtiley * TILE_SIZE); + + x0 = ui->dragstartx; + y0 = ui->dragstarty; + xA = ui->dragstarty; + yA = TILE_SIZE-1 - ui->dragstartx; + xF = TILE_SIZE-1 - ui->dragstartx; + yF = TILE_SIZE-1 - ui->dragstarty; + xC = TILE_SIZE-1 - ui->dragstarty; + yC = ui->dragstartx; + + d0 = (mx-x0)*(mx-x0) + (my-y0)*(my-y0); + dA = (mx-xA)*(mx-xA) + (my-yA)*(my-yA); + dF = (mx-xF)*(mx-xF) + (my-yF)*(my-yF); + dC = (mx-xC)*(mx-xC) + (my-yC)*(my-yC); + + dmin = min(min(d0,dA),min(dF,dC)); + + if (d0 == dmin) { + return nullret; + } else if (dF == dmin) { + action = ROTATE_180; + ui->dragstartx = xF; + ui->dragstarty = yF; + ui->dragged = TRUE; + } else if (dA == dmin) { + action = ROTATE_LEFT; + ui->dragstartx = xA; + ui->dragstarty = yA; + ui->dragged = TRUE; + } else /* dC == dmin */ { + action = ROTATE_RIGHT; + ui->dragstartx = xC; + ui->dragstarty = yC; + ui->dragged = TRUE; + } + } else if (button == LEFT_RELEASE +#ifndef STYLUS_BASED + || button == RIGHT_RELEASE +#endif + ) { + if (!ui->dragged) { + /* + * There was a click but no perceptible drag: + * revert to single-click behaviour. + */ + tx = ui->dragtilex; + ty = ui->dragtiley; + + if (button == LEFT_RELEASE) + action = ROTATE_LEFT; + else + action = ROTATE_RIGHT; + } else + return nullret; /* no action */ + } + +#else /* USE_DRAGGING */ + + action = (button == LEFT_BUTTON ? ROTATE_LEFT : + button == RIGHT_BUTTON ? ROTATE_RIGHT : TOGGLE_LOCK); + +#endif /* USE_DRAGGING */ + + } else if (IS_CURSOR_MOVE(button)) { + switch (button) { + case CURSOR_UP: dir = U; break; + case CURSOR_DOWN: dir = D; break; + case CURSOR_LEFT: dir = L; break; + case CURSOR_RIGHT: dir = R; break; + default: return nullret; + } + if (shift && ctrl) action = MOVE_ORIGIN_AND_SOURCE; + else if (shift) action = MOVE_ORIGIN; + else if (ctrl) action = MOVE_SOURCE; + else action = MOVE_CURSOR; + } else if (button == 'a' || button == 's' || button == 'd' || + button == 'A' || button == 'S' || button == 'D' || + button == 'f' || button == 'F' || + IS_CURSOR_SELECT(button)) { + tx = ui->cur_x; + ty = ui->cur_y; + if (button == 'a' || button == 'A' || button == CURSOR_SELECT) + action = ROTATE_LEFT; + else if (button == 's' || button == 'S' || button == CURSOR_SELECT2) + action = TOGGLE_LOCK; + else if (button == 'd' || button == 'D') + action = ROTATE_RIGHT; + else if (button == 'f' || button == 'F') + action = ROTATE_180; + ui->cur_visible = TRUE; + } else if (button == 'j' || button == 'J') { + /* XXX should we have some mouse control for this? */ + action = JUMBLE; + } else + return nullret; + + /* + * The middle button locks or unlocks a tile. (A locked tile + * cannot be turned, and is visually marked as being locked. + * This is a convenience for the player, so that once they are + * sure which way round a tile goes, they can lock it and thus + * avoid forgetting later on that they'd already done that one; + * and the locking also prevents them turning the tile by + * accident. If they change their mind, another middle click + * unlocks it.) + */ + if (action == TOGGLE_LOCK) { + char buf[80]; + sprintf(buf, "L%d,%d", tx, ty); + return dupstr(buf); + } else if (action == ROTATE_LEFT || action == ROTATE_RIGHT || + action == ROTATE_180) { + char buf[80]; + + /* + * The left and right buttons have no effect if clicked on a + * locked tile. + */ + if (tile(state, tx, ty) & LOCKED) + return nullret; + + /* + * Otherwise, turn the tile one way or the other. Left button + * turns anticlockwise; right button turns clockwise. + */ + sprintf(buf, "%c%d,%d", (int)(action == ROTATE_LEFT ? 'A' : + action == ROTATE_RIGHT ? 'C' : 'F'), tx, ty); + return dupstr(buf); + } else if (action == JUMBLE) { + /* + * Jumble all unlocked tiles to random orientations. + */ + + int jx, jy, maxlen; + char *ret, *p; + + /* + * Maximum string length assumes no int can be converted to + * decimal and take more than 11 digits! + */ + maxlen = state->width * state->height * 25 + 3; + + ret = snewn(maxlen, char); + p = ret; + *p++ = 'J'; + + for (jy = 0; jy < state->height; jy++) { + for (jx = 0; jx < state->width; jx++) { + if (!(tile(state, jx, jy) & LOCKED)) { + int rot = random_upto(ui->rs, 4); + if (rot) { + p += sprintf(p, ";%c%d,%d", "AFC"[rot-1], jx, jy); + } + } + } + } + *p++ = '\0'; + assert(p - ret < maxlen); + ret = sresize(ret, p - ret, char); + + return ret; + } else if (action == MOVE_ORIGIN || action == MOVE_SOURCE || + action == MOVE_ORIGIN_AND_SOURCE || action == MOVE_CURSOR) { + assert(dir != 0); + if (action == MOVE_ORIGIN || action == MOVE_ORIGIN_AND_SOURCE) { + if (state->wrapping) { + OFFSET(ui->org_x, ui->org_y, ui->org_x, ui->org_y, dir, state); + } else return nullret; /* disallowed for non-wrapping grids */ + } + if (action == MOVE_SOURCE || action == MOVE_ORIGIN_AND_SOURCE) { + OFFSET(ui->cx, ui->cy, ui->cx, ui->cy, dir, state); + } + if (action == MOVE_CURSOR) { + OFFSET(ui->cur_x, ui->cur_y, ui->cur_x, ui->cur_y, dir, state); + ui->cur_visible = TRUE; + } + return ""; + } else { + return NULL; + } +} - barrier(state, x1, y1) |= d1; - barrier(state, x2, y2) |= d2; +static game_state *execute_move(const game_state *from, const char *move) +{ + game_state *ret; + int tx = -1, ty = -1, n, noanim, orig; + + ret = dup_game(from); + + if (move[0] == 'J' || move[0] == 'S') { + if (move[0] == 'S') + ret->used_solve = TRUE; + + move++; + if (*move == ';') + move++; + noanim = TRUE; + } else + noanim = FALSE; + + ret->last_rotate_dir = 0; /* suppress animation */ + ret->last_rotate_x = ret->last_rotate_y = 0; + + while (*move) { + if ((move[0] == 'A' || move[0] == 'C' || + move[0] == 'F' || move[0] == 'L') && + sscanf(move+1, "%d,%d%n", &tx, &ty, &n) >= 2 && + tx >= 0 && tx < from->width && ty >= 0 && ty < from->height) { + orig = tile(ret, tx, ty); + if (move[0] == 'A') { + tile(ret, tx, ty) = A(orig); + if (!noanim) + ret->last_rotate_dir = +1; + } else if (move[0] == 'F') { + tile(ret, tx, ty) = F(orig); + if (!noanim) + ret->last_rotate_dir = +2; /* + for sake of argument */ + } else if (move[0] == 'C') { + tile(ret, tx, ty) = C(orig); + if (!noanim) + ret->last_rotate_dir = -1; + } else { + assert(move[0] == 'L'); + tile(ret, tx, ty) ^= LOCKED; + } - nbarriers--; + move += 1 + n; + if (*move == ';') move++; + } else { + free_game(ret); + return NULL; + } + } + if (!noanim) { + if (tx == -1 || ty == -1) { free_game(ret); return NULL; } + ret->last_rotate_x = tx; + ret->last_rotate_y = ty; } /* - * Clean up the rest of the barrier list. + * Check whether the game has been completed. + * + * For this purpose it doesn't matter where the source square is, + * because we can start from anywhere (or, at least, any square + * that's non-empty!), and correctly determine whether the game is + * completed. */ { - struct xyd *xyd; + unsigned char *active; + int pos; + int complete = TRUE; - while ( (xyd = delpos234(barriers, 0)) != NULL) - sfree(xyd); + for (pos = 0; pos < ret->width * ret->height; pos++) + if (ret->tiles[pos] & 0xF) + break; + + if (pos < ret->width * ret->height) { + active = compute_active(ret, pos % ret->width, pos / ret->width); + + for (pos = 0; pos < ret->width * ret->height; pos++) + if ((ret->tiles[pos] & 0xF) && !active[pos]) { + complete = FALSE; + break; + } + + sfree(active); + } - freetree234(barriers); + if (complete) + ret->completed = TRUE; } - random_free(rs); + return ret; +} - return state; + +/* ---------------------------------------------------------------------- + * Routines for drawing the game position on the screen. + */ + +static game_drawstate *game_new_drawstate(drawing *dr, const game_state *state) +{ + game_drawstate *ds = snew(game_drawstate); + int i; + + ds->started = FALSE; + ds->width = state->width; + ds->height = state->height; + ds->org_x = ds->org_y = -1; + ds->visible = snewn(state->width * state->height, int); + ds->tilesize = 0; /* undecided yet */ + for (i = 0; i < state->width * state->height; i++) + ds->visible[i] = -1; + + return ds; } -game_state *dup_game(game_state *state) +static void game_free_drawstate(drawing *dr, game_drawstate *ds) { - game_state *ret; + sfree(ds->visible); + sfree(ds); +} - ret = snew(game_state); - ret->width = state->width; - ret->height = state->height; - ret->wrapping = state->wrapping; - ret->completed = state->completed; - ret->tiles = snewn(state->width * state->height, unsigned char); - memcpy(ret->tiles, state->tiles, state->width * state->height); - ret->barriers = snewn(state->width * state->height, unsigned char); - memcpy(ret->barriers, state->barriers, state->width * state->height); +static void game_compute_size(const game_params *params, int tilesize, + int *x, int *y) +{ + *x = WINDOW_OFFSET * 2 + tilesize * params->width + TILE_BORDER; + *y = WINDOW_OFFSET * 2 + tilesize * params->height + TILE_BORDER; +} + +static void game_set_size(drawing *dr, game_drawstate *ds, + const game_params *params, int tilesize) +{ + ds->tilesize = tilesize; +} + +static float *game_colours(frontend *fe, int *ncolours) +{ + float *ret; + + ret = snewn(NCOLOURS * 3, float); + *ncolours = NCOLOURS; + + /* + * Basic background colour is whatever the front end thinks is + * a sensible default. + */ + frontend_default_colour(fe, &ret[COL_BACKGROUND * 3]); + + /* + * Wires are black. + */ + ret[COL_WIRE * 3 + 0] = 0.0F; + ret[COL_WIRE * 3 + 1] = 0.0F; + ret[COL_WIRE * 3 + 2] = 0.0F; + + /* + * Powered wires and powered endpoints are cyan. + */ + ret[COL_POWERED * 3 + 0] = 0.0F; + ret[COL_POWERED * 3 + 1] = 1.0F; + ret[COL_POWERED * 3 + 2] = 1.0F; + + /* + * Barriers are red. + */ + ret[COL_BARRIER * 3 + 0] = 1.0F; + ret[COL_BARRIER * 3 + 1] = 0.0F; + ret[COL_BARRIER * 3 + 2] = 0.0F; + + /* + * Highlighted loops are red as well. + */ + ret[COL_LOOP * 3 + 0] = 1.0F; + ret[COL_LOOP * 3 + 1] = 0.0F; + ret[COL_LOOP * 3 + 2] = 0.0F; + + /* + * Unpowered endpoints are blue. + */ + ret[COL_ENDPOINT * 3 + 0] = 0.0F; + ret[COL_ENDPOINT * 3 + 1] = 0.0F; + ret[COL_ENDPOINT * 3 + 2] = 1.0F; + + /* + * Tile borders are a darker grey than the background. + */ + ret[COL_BORDER * 3 + 0] = 0.5F * ret[COL_BACKGROUND * 3 + 0]; + ret[COL_BORDER * 3 + 1] = 0.5F * ret[COL_BACKGROUND * 3 + 1]; + ret[COL_BORDER * 3 + 2] = 0.5F * ret[COL_BACKGROUND * 3 + 2]; + + /* + * Locked tiles are a grey in between those two. + */ + ret[COL_LOCKED * 3 + 0] = 0.75F * ret[COL_BACKGROUND * 3 + 0]; + ret[COL_LOCKED * 3 + 1] = 0.75F * ret[COL_BACKGROUND * 3 + 1]; + ret[COL_LOCKED * 3 + 2] = 0.75F * ret[COL_BACKGROUND * 3 + 2]; return ret; } -void free_game(game_state *state) +static void draw_filled_line(drawing *dr, int x1, int y1, int x2, int y2, + int colour) { - sfree(state->tiles); - sfree(state->barriers); - sfree(state); + draw_line(dr, x1-1, y1, x2-1, y2, COL_WIRE); + draw_line(dr, x1+1, y1, x2+1, y2, COL_WIRE); + draw_line(dr, x1, y1-1, x2, y2-1, COL_WIRE); + draw_line(dr, x1, y1+1, x2, y2+1, COL_WIRE); + draw_line(dr, x1, y1, x2, y2, colour); } -/* ---------------------------------------------------------------------- - * Utility routine. - */ +static void draw_rect_coords(drawing *dr, int x1, int y1, int x2, int y2, + int colour) +{ + int mx = (x1 < x2 ? x1 : x2); + int my = (y1 < y2 ? y1 : y2); + int dx = (x2 + x1 - 2*mx + 1); + int dy = (y2 + y1 - 2*my + 1); + + draw_rect(dr, mx, my, dx, dy, colour); +} /* - * Compute which squares are reachable from the centre square, as a - * quick visual aid to determining how close the game is to - * completion. This is also a simple way to tell if the game _is_ - * completed - just call this function and see whether every square - * is marked active. + * draw_barrier_corner() and draw_barrier() are passed physical coords */ -static unsigned char *compute_active(game_state *state) +static void draw_barrier_corner(drawing *dr, game_drawstate *ds, + int x, int y, int dx, int dy, int phase) { - unsigned char *active; - tree234 *todo; - struct xyd *xyd; + int bx = WINDOW_OFFSET + TILE_SIZE * x; + int by = WINDOW_OFFSET + TILE_SIZE * y; + int x1, y1; + + x1 = (dx > 0 ? TILE_SIZE+TILE_BORDER-1 : 0); + y1 = (dy > 0 ? TILE_SIZE+TILE_BORDER-1 : 0); + + if (phase == 0) { + draw_rect_coords(dr, bx+x1+dx, by+y1, + bx+x1-TILE_BORDER*dx, by+y1-(TILE_BORDER-1)*dy, + COL_WIRE); + draw_rect_coords(dr, bx+x1, by+y1+dy, + bx+x1-(TILE_BORDER-1)*dx, by+y1-TILE_BORDER*dy, + COL_WIRE); + } else { + draw_rect_coords(dr, bx+x1, by+y1, + bx+x1-(TILE_BORDER-1)*dx, by+y1-(TILE_BORDER-1)*dy, + COL_BARRIER); + } +} - active = snewn(state->width * state->height, unsigned char); - memset(active, 0, state->width * state->height); +static void draw_barrier(drawing *dr, game_drawstate *ds, + int x, int y, int dir, int phase) +{ + int bx = WINDOW_OFFSET + TILE_SIZE * x; + int by = WINDOW_OFFSET + TILE_SIZE * y; + int x1, y1, w, h; + + x1 = (X(dir) > 0 ? TILE_SIZE : X(dir) == 0 ? TILE_BORDER : 0); + y1 = (Y(dir) > 0 ? TILE_SIZE : Y(dir) == 0 ? TILE_BORDER : 0); + w = (X(dir) ? TILE_BORDER : TILE_SIZE - TILE_BORDER); + h = (Y(dir) ? TILE_BORDER : TILE_SIZE - TILE_BORDER); + + if (phase == 0) { + draw_rect(dr, bx+x1-X(dir), by+y1-Y(dir), w, h, COL_WIRE); + } else { + draw_rect(dr, bx+x1, by+y1, w, h, COL_BARRIER); + } +} + +/* + * draw_tile() is passed physical coordinates + */ +static void draw_tile(drawing *dr, const game_state *state, game_drawstate *ds, + int x, int y, int tile, int src, float angle, int cursor) +{ + int bx = WINDOW_OFFSET + TILE_SIZE * x; + int by = WINDOW_OFFSET + TILE_SIZE * y; + float matrix[4]; + float cx, cy, ex, ey, tx, ty; + int dir, col, phase; /* - * We only store (x,y) pairs in todo, but it's easier to reuse - * xyd_cmp and just store direction 0 every time. + * When we draw a single tile, we must draw everything up to + * and including the borders around the tile. This means that + * if the neighbouring tiles have connections to those borders, + * we must draw those connections on the borders themselves. */ - todo = newtree234(xyd_cmp); - add234(todo, new_xyd(state->width / 2, state->height / 2, 0)); - - while ( (xyd = delpos234(todo, 0)) != NULL) { - int x1, y1, d1, x2, y2, d2; - x1 = xyd->x; - y1 = xyd->y; - sfree(xyd); + clip(dr, bx, by, TILE_SIZE+TILE_BORDER, TILE_SIZE+TILE_BORDER); - for (d1 = 1; d1 < 0x10; d1 <<= 1) { - OFFSET(x2, y2, x1, y1, d1, state); - d2 = F(d1); + /* + * So. First blank the tile out completely: draw a big + * rectangle in border colour, and a smaller rectangle in + * background colour to fill it in. + */ + draw_rect(dr, bx, by, TILE_SIZE+TILE_BORDER, TILE_SIZE+TILE_BORDER, + COL_BORDER); + draw_rect(dr, bx+TILE_BORDER, by+TILE_BORDER, + TILE_SIZE-TILE_BORDER, TILE_SIZE-TILE_BORDER, + tile & LOCKED ? COL_LOCKED : COL_BACKGROUND); - /* - * If the next tile in this direction is connected to - * us, and there isn't a barrier in the way, and it - * isn't already marked active, then mark it active and - * add it to the to-examine list. - */ - if ((tile(state, x1, y1) & d1) && - (tile(state, x2, y2) & d2) && - !(barrier(state, x1, y1) & d1) && - !index(state, active, x2, y2)) { - index(state, active, x2, y2) = 1; - add234(todo, new_xyd(x2, y2, 0)); - } - } + /* + * Draw an inset outline rectangle as a cursor, in whichever of + * COL_LOCKED and COL_BACKGROUND we aren't currently drawing + * in. + */ + if (cursor) { + draw_line(dr, bx+TILE_SIZE/8, by+TILE_SIZE/8, + bx+TILE_SIZE/8, by+TILE_SIZE-TILE_SIZE/8, + tile & LOCKED ? COL_BACKGROUND : COL_LOCKED); + draw_line(dr, bx+TILE_SIZE/8, by+TILE_SIZE/8, + bx+TILE_SIZE-TILE_SIZE/8, by+TILE_SIZE/8, + tile & LOCKED ? COL_BACKGROUND : COL_LOCKED); + draw_line(dr, bx+TILE_SIZE-TILE_SIZE/8, by+TILE_SIZE/8, + bx+TILE_SIZE-TILE_SIZE/8, by+TILE_SIZE-TILE_SIZE/8, + tile & LOCKED ? COL_BACKGROUND : COL_LOCKED); + draw_line(dr, bx+TILE_SIZE/8, by+TILE_SIZE-TILE_SIZE/8, + bx+TILE_SIZE-TILE_SIZE/8, by+TILE_SIZE-TILE_SIZE/8, + tile & LOCKED ? COL_BACKGROUND : COL_LOCKED); } - /* Now we expect the todo list to have shrunk to zero size. */ - assert(count234(todo) == 0); - freetree234(todo); - return active; -} + /* + * Set up the rotation matrix. + */ + matrix[0] = (float)cos(angle * PI / 180.0); + matrix[1] = (float)-sin(angle * PI / 180.0); + matrix[2] = (float)sin(angle * PI / 180.0); + matrix[3] = (float)cos(angle * PI / 180.0); -/* ---------------------------------------------------------------------- - * Process a move. - */ -game_state *make_move(game_state *state, int x, int y, int button) -{ - game_state *ret; - int tx, ty, orig; + /* + * Draw the wires. + */ + cx = cy = TILE_BORDER + (TILE_SIZE-TILE_BORDER) / 2.0F - 0.5F; + col = (tile & ACTIVE ? COL_POWERED : COL_WIRE); + for (dir = 1; dir < 0x10; dir <<= 1) { + if (tile & dir) { + ex = (TILE_SIZE - TILE_BORDER - 1.0F) / 2.0F * X(dir); + ey = (TILE_SIZE - TILE_BORDER - 1.0F) / 2.0F * Y(dir); + MATMUL(tx, ty, matrix, ex, ey); + draw_filled_line(dr, bx+(int)cx, by+(int)cy, + bx+(int)(cx+tx), by+(int)(cy+ty), + COL_WIRE); + } + } + for (dir = 1; dir < 0x10; dir <<= 1) { + if (tile & dir) { + ex = (TILE_SIZE - TILE_BORDER - 1.0F) / 2.0F * X(dir); + ey = (TILE_SIZE - TILE_BORDER - 1.0F) / 2.0F * Y(dir); + MATMUL(tx, ty, matrix, ex, ey); + draw_line(dr, bx+(int)cx, by+(int)cy, + bx+(int)(cx+tx), by+(int)(cy+ty), + (tile & LOOP(dir)) ? COL_LOOP : col); + } + } + /* If we've drawn any loop-highlighted arms, make sure the centre + * point is loop-coloured rather than a later arm overwriting it. */ + if (tile & (RLOOP | ULOOP | LLOOP | DLOOP)) + draw_rect(dr, bx+(int)cx, by+(int)cy, 1, 1, COL_LOOP); /* - * All moves in Net are made with the mouse. + * Draw the box in the middle. We do this in blue if the tile + * is an unpowered endpoint, in cyan if the tile is a powered + * endpoint, in black if the tile is the centrepiece, and + * otherwise not at all. */ - if (button != LEFT_BUTTON && - button != MIDDLE_BUTTON && - button != RIGHT_BUTTON) - return NULL; + col = -1; + if (src) + col = COL_WIRE; + else if (COUNT(tile) == 1) { + col = (tile & ACTIVE ? COL_POWERED : COL_ENDPOINT); + } + if (col >= 0) { + int i, points[8]; + + points[0] = +1; points[1] = +1; + points[2] = +1; points[3] = -1; + points[4] = -1; points[5] = -1; + points[6] = -1; points[7] = +1; + + for (i = 0; i < 8; i += 2) { + ex = (TILE_SIZE * 0.24F) * points[i]; + ey = (TILE_SIZE * 0.24F) * points[i+1]; + MATMUL(tx, ty, matrix, ex, ey); + points[i] = bx+(int)(cx+tx); + points[i+1] = by+(int)(cy+ty); + } + + draw_polygon(dr, points, 4, col, COL_WIRE); + } /* - * The button must have been clicked on a valid tile. + * Draw the points on the border if other tiles are connected + * to us. */ - x -= WINDOW_OFFSET; - y -= WINDOW_OFFSET; - if (x < 0 || y < 0) - return NULL; - tx = x / TILE_SIZE; - ty = y / TILE_SIZE; - if (tx >= state->width || ty >= state->height) - return NULL; - if (tx % TILE_SIZE >= TILE_SIZE - TILE_BORDER || - ty % TILE_SIZE >= TILE_SIZE - TILE_BORDER) - return NULL; + for (dir = 1; dir < 0x10; dir <<= 1) { + int dx, dy, px, py, lx, ly, vx, vy, ox, oy; + + dx = X(dir); + dy = Y(dir); + + ox = x + dx; + oy = y + dy; + + if (ox < 0 || ox >= state->width || oy < 0 || oy >= state->height) + continue; + + if (!(tile(state, GX(ox), GY(oy)) & F(dir))) + continue; + + px = bx + (int)(dx>0 ? TILE_SIZE + TILE_BORDER - 1 : dx<0 ? 0 : cx); + py = by + (int)(dy>0 ? TILE_SIZE + TILE_BORDER - 1 : dy<0 ? 0 : cy); + lx = dx * (TILE_BORDER-1); + ly = dy * (TILE_BORDER-1); + vx = (dy ? 1 : 0); + vy = (dx ? 1 : 0); + + if (angle == 0.0 && (tile & dir)) { + /* + * If we are fully connected to the other tile, we must + * draw right across the tile border. (We can use our + * own ACTIVE state to determine what colour to do this + * in: if we are fully connected to the other tile then + * the two ACTIVE states will be the same.) + */ + draw_rect_coords(dr, px-vx, py-vy, px+lx+vx, py+ly+vy, COL_WIRE); + draw_rect_coords(dr, px, py, px+lx, py+ly, + ((tile & LOOP(dir)) ? COL_LOOP : + (tile & ACTIVE) ? COL_POWERED : + COL_WIRE)); + } else { + /* + * The other tile extends into our border, but isn't + * actually connected to us. Just draw a single black + * dot. + */ + draw_rect_coords(dr, px, py, px, py, COL_WIRE); + } + } /* - * The middle button locks or unlocks a tile. (A locked tile - * cannot be turned, and is visually marked as being locked. - * This is a convenience for the player, so that once they are - * sure which way round a tile goes, they can lock it and thus - * avoid forgetting later on that they'd already done that one; - * and the locking also prevents them turning the tile by - * accident. If they change their mind, another middle click - * unlocks it.) + * Draw barrier corners, and then barriers. */ - if (button == MIDDLE_BUTTON) { - ret = dup_game(state); - tile(ret, tx, ty) ^= LOCKED; - return ret; + for (phase = 0; phase < 2; phase++) { + for (dir = 1; dir < 0x10; dir <<= 1) { + int x1, y1, corner = FALSE; + /* + * If at least one barrier terminates at the corner + * between dir and A(dir), draw a barrier corner. + */ + if (barrier(state, GX(x), GY(y)) & (dir | A(dir))) { + corner = TRUE; + } else { + /* + * Only count barriers terminating at this corner + * if they're physically next to the corner. (That + * is, if they've wrapped round from the far side + * of the screen, they don't count.) + */ + x1 = x + X(dir); + y1 = y + Y(dir); + if (x1 >= 0 && x1 < state->width && + y1 >= 0 && y1 < state->height && + (barrier(state, GX(x1), GY(y1)) & A(dir))) { + corner = TRUE; + } else { + x1 = x + X(A(dir)); + y1 = y + Y(A(dir)); + if (x1 >= 0 && x1 < state->width && + y1 >= 0 && y1 < state->height && + (barrier(state, GX(x1), GY(y1)) & dir)) + corner = TRUE; + } + } + + if (corner) { + /* + * At least one barrier terminates here. Draw a + * corner. + */ + draw_barrier_corner(dr, ds, x, y, + X(dir)+X(A(dir)), Y(dir)+Y(A(dir)), + phase); + } + } + + for (dir = 1; dir < 0x10; dir <<= 1) + if (barrier(state, GX(x), GY(y)) & dir) + draw_barrier(dr, ds, x, y, dir, phase); } + unclip(dr); + + draw_update(dr, bx, by, TILE_SIZE+TILE_BORDER, TILE_SIZE+TILE_BORDER); +} + +static void game_redraw(drawing *dr, game_drawstate *ds, + const game_state *oldstate, const game_state *state, + int dir, const game_ui *ui, + float t, float ft) +{ + int x, y, tx, ty, frame, last_rotate_dir, moved_origin = FALSE; + unsigned char *active; + int *loops; + float angle = 0.0; + /* - * The left and right buttons have no effect if clicked on a - * locked tile. + * Clear the screen, and draw the exterior barrier lines, if + * this is our first call or if the origin has changed. */ - if (tile(state, tx, ty) & LOCKED) - return NULL; + if (!ds->started || ui->org_x != ds->org_x || ui->org_y != ds->org_y) { + int phase; + + ds->started = TRUE; + + draw_rect(dr, 0, 0, + WINDOW_OFFSET * 2 + TILE_SIZE * state->width + TILE_BORDER, + WINDOW_OFFSET * 2 + TILE_SIZE * state->height + TILE_BORDER, + COL_BACKGROUND); + + ds->org_x = ui->org_x; + ds->org_y = ui->org_y; + moved_origin = TRUE; + + draw_update(dr, 0, 0, + WINDOW_OFFSET*2 + TILE_SIZE*state->width + TILE_BORDER, + WINDOW_OFFSET*2 + TILE_SIZE*state->height + TILE_BORDER); + + for (phase = 0; phase < 2; phase++) { + + for (x = 0; x < ds->width; x++) { + if (x+1 < ds->width) { + if (barrier(state, GX(x), GY(0)) & R) + draw_barrier_corner(dr, ds, x, -1, +1, +1, phase); + if (barrier(state, GX(x), GY(ds->height-1)) & R) + draw_barrier_corner(dr, ds, x, ds->height, +1, -1, phase); + } + if (barrier(state, GX(x), GY(0)) & U) { + draw_barrier_corner(dr, ds, x, -1, -1, +1, phase); + draw_barrier_corner(dr, ds, x, -1, +1, +1, phase); + draw_barrier(dr, ds, x, -1, D, phase); + } + if (barrier(state, GX(x), GY(ds->height-1)) & D) { + draw_barrier_corner(dr, ds, x, ds->height, -1, -1, phase); + draw_barrier_corner(dr, ds, x, ds->height, +1, -1, phase); + draw_barrier(dr, ds, x, ds->height, U, phase); + } + } + + for (y = 0; y < ds->height; y++) { + if (y+1 < ds->height) { + if (barrier(state, GX(0), GY(y)) & D) + draw_barrier_corner(dr, ds, -1, y, +1, +1, phase); + if (barrier(state, GX(ds->width-1), GY(y)) & D) + draw_barrier_corner(dr, ds, ds->width, y, -1, +1, phase); + } + if (barrier(state, GX(0), GY(y)) & L) { + draw_barrier_corner(dr, ds, -1, y, +1, -1, phase); + draw_barrier_corner(dr, ds, -1, y, +1, +1, phase); + draw_barrier(dr, ds, -1, y, R, phase); + } + if (barrier(state, GX(ds->width-1), GY(y)) & R) { + draw_barrier_corner(dr, ds, ds->width, y, -1, -1, phase); + draw_barrier_corner(dr, ds, ds->width, y, -1, +1, phase); + draw_barrier(dr, ds, ds->width, y, L, phase); + } + } + } + } + + tx = ty = -1; + last_rotate_dir = dir==-1 ? oldstate->last_rotate_dir : + state->last_rotate_dir; + if (oldstate && (t < ROTATE_TIME) && last_rotate_dir) { + /* + * We're animating a single tile rotation. Find the turning + * tile. + */ + tx = (dir==-1 ? oldstate->last_rotate_x : state->last_rotate_x); + ty = (dir==-1 ? oldstate->last_rotate_y : state->last_rotate_y); + angle = last_rotate_dir * dir * 90.0F * (t / ROTATE_TIME); + state = oldstate; + } + + frame = -1; + if (ft > 0) { + /* + * We're animating a completion flash. Find which frame + * we're at. + */ + frame = (int)(ft / FLASH_FRAME); + } /* - * Otherwise, turn the tile one way or the other. Left button - * turns anticlockwise; right button turns clockwise. + * Draw any tile which differs from the way it was last drawn. */ - ret = dup_game(state); - orig = tile(ret, tx, ty); - if (button == LEFT_BUTTON) - tile(ret, tx, ty) = A(orig); - else - tile(ret, tx, ty) = C(orig); + active = compute_active(state, ui->cx, ui->cy); + loops = compute_loops(state); + + for (x = 0; x < ds->width; x++) + for (y = 0; y < ds->height; y++) { + int c = tile(state, GX(x), GY(y)) | + index(state, active, GX(x), GY(y)) | + index(state, loops, GX(x), GY(y)); + int is_src = GX(x) == ui->cx && GY(y) == ui->cy; + int is_anim = GX(x) == tx && GY(y) == ty; + int is_cursor = ui->cur_visible && + GX(x) == ui->cur_x && GY(y) == ui->cur_y; + + /* + * In a completion flash, we adjust the LOCKED bit + * depending on our distance from the centre point and + * the frame number. + */ + if (frame >= 0) { + int rcx = RX(ui->cx), rcy = RY(ui->cy); + int xdist, ydist, dist; + xdist = (x < rcx ? rcx - x : x - rcx); + ydist = (y < rcy ? rcy - y : y - rcy); + dist = (xdist > ydist ? xdist : ydist); + + if (frame >= dist && frame < dist+4) { + int lock = (frame - dist) & 1; + lock = lock ? LOCKED : 0; + c = (c &~ LOCKED) | lock; + } + } + + if (moved_origin || + index(state, ds->visible, x, y) != c || + index(state, ds->visible, x, y) == -1 || + is_src || is_anim || is_cursor) { + draw_tile(dr, state, ds, x, y, c, + is_src, (is_anim ? angle : 0.0F), is_cursor); + if (is_src || is_anim || is_cursor) + index(state, ds->visible, x, y) = -1; + else + index(state, ds->visible, x, y) = c; + } + } /* - * Check whether the game has been completed. + * Update the status bar. */ { - unsigned char *active = compute_active(ret); - int x1, y1; - int complete = TRUE; + char statusbuf[256], *p; + int i, n, n2, a; + int complete = FALSE; + + p = statusbuf; + *p = '\0'; /* ensure even an empty status string is terminated */ + + if (state->used_solve) { + p += sprintf(p, "Auto-solved. "); + complete = TRUE; + } else if (state->completed) { + p += sprintf(p, "COMPLETED! "); + complete = TRUE; + } + + /* + * Omit the 'Active: n/N' counter completely if the source + * tile is a completely empty one, because then the active + * count can't help but read '1'. + */ + if (tile(state, ui->cx, ui->cy) & 0xF) { + n = state->width * state->height; + for (i = a = n2 = 0; i < n; i++) { + if (active[i]) + a++; + if (state->tiles[i] & 0xF) + n2++; + } + + /* + * Also, if we're displaying a completion indicator and + * the game is still in its completed state (i.e. every + * tile is active), we might as well omit this too. + */ + if (!complete || a < n2) + p += sprintf(p, "Active: %d/%d", a, n2); + } + + status_bar(dr, statusbuf); + } - for (x1 = 0; x1 < ret->width; x1++) - for (y1 = 0; y1 < ret->height; y1++) - if (!index(ret, active, x1, y1)) { - complete = FALSE; - goto break_label; /* break out of two loops at once */ - } - break_label: + sfree(active); + sfree(loops); +} - sfree(active); +static float game_anim_length(const game_state *oldstate, + const game_state *newstate, int dir, game_ui *ui) +{ + int last_rotate_dir; - if (complete) - ret->completed = TRUE; + /* + * Don't animate if last_rotate_dir is zero. + */ + last_rotate_dir = dir==-1 ? oldstate->last_rotate_dir : + newstate->last_rotate_dir; + if (last_rotate_dir) + return ROTATE_TIME; + + return 0.0F; +} + +static float game_flash_length(const game_state *oldstate, + const game_state *newstate, int dir, game_ui *ui) +{ + /* + * If the game has just been completed, we display a completion + * flash. + */ + if (!oldstate->completed && newstate->completed && + !oldstate->used_solve && !newstate->used_solve) { + int size = 0; + if (size < newstate->width) + size = newstate->width; + if (size < newstate->height) + size = newstate->height; + return FLASH_FRAME * (size+4); } - return ret; + return 0.0F; } -/* ---------------------------------------------------------------------- - * Routines for drawing the game position on the screen. - */ +static int game_status(const game_state *state) +{ + return state->completed ? +1 : 0; +} -/* ---------------------------------------------------------------------- - * Test code. - */ +static int game_timing_state(const game_state *state, game_ui *ui) +{ + return TRUE; +} -#ifdef TESTMODE +static void game_print_size(const game_params *params, float *x, float *y) +{ + int pw, ph; + + /* + * I'll use 8mm squares by default. + */ + game_compute_size(params, 800, &pw, &ph); + *x = pw / 100.0F; + *y = ph / 100.0F; +} -int main(void) +static void draw_diagram(drawing *dr, game_drawstate *ds, int x, int y, + int topleft, int v, int drawlines, int ink) { - game_params params = { 13, 11, TRUE, 0.1 }; - char *seed; - game_state *state; - unsigned char *active; + int tx, ty, cx, cy, r, br, k, thick; - seed = "123"; - state = new_game(¶ms, seed); - active = compute_active(state); + tx = WINDOW_OFFSET + TILE_SIZE * x; + ty = WINDOW_OFFSET + TILE_SIZE * y; - { - int x, y; + /* + * Find our centre point. + */ + if (topleft) { + cx = tx + (v & L ? TILE_SIZE / 4 : TILE_SIZE / 6); + cy = ty + (v & U ? TILE_SIZE / 4 : TILE_SIZE / 6); + r = TILE_SIZE / 8; + br = TILE_SIZE / 32; + } else { + cx = tx + TILE_SIZE / 2; + cy = ty + TILE_SIZE / 2; + r = TILE_SIZE / 2; + br = TILE_SIZE / 8; + } + thick = r / 20; - printf("\033)0\016"); - for (y = 0; y < state->height; y++) { - for (x = 0; x < state->width; x++) { - if (index(state, active, x, y)) - printf("\033[1;32m"); - else - printf("\033[0;31m"); - putchar("~``m`qjv`lxtkwua"[tile(state, x, y)]); + /* + * Draw the square block if we have an endpoint. + */ + if (v == 1 || v == 2 || v == 4 || v == 8) + draw_rect(dr, cx - br, cy - br, br*2, br*2, ink); + + /* + * Draw each radial line. + */ + if (drawlines) { + for (k = 1; k < 16; k *= 2) + if (v & k) { + int x1 = min(cx, cx + (r-thick) * X(k)); + int x2 = max(cx, cx + (r-thick) * X(k)); + int y1 = min(cy, cy + (r-thick) * Y(k)); + int y2 = max(cy, cy + (r-thick) * Y(k)); + draw_rect(dr, x1 - thick, y1 - thick, + (x2 - x1) + 2*thick, (y2 - y1) + 2*thick, ink); } - printf("\033[m\n"); - } - printf("\017"); } +} - free_game(state); +static void game_print(drawing *dr, const game_state *state, int tilesize) +{ + int w = state->width, h = state->height; + int ink = print_mono_colour(dr, 0); + int x, y; - return 0; + /* Ick: fake up `ds->tilesize' for macro expansion purposes */ + game_drawstate ads, *ds = &ads; + game_set_size(dr, ds, NULL, tilesize); + + /* + * Border. + */ + print_line_width(dr, TILE_SIZE / (state->wrapping ? 128 : 12)); + draw_rect_outline(dr, WINDOW_OFFSET, WINDOW_OFFSET, + TILE_SIZE * w, TILE_SIZE * h, ink); + + /* + * Grid. + */ + print_line_width(dr, TILE_SIZE / 128); + for (x = 1; x < w; x++) + draw_line(dr, WINDOW_OFFSET + TILE_SIZE * x, WINDOW_OFFSET, + WINDOW_OFFSET + TILE_SIZE * x, WINDOW_OFFSET + TILE_SIZE * h, + ink); + for (y = 1; y < h; y++) + draw_line(dr, WINDOW_OFFSET, WINDOW_OFFSET + TILE_SIZE * y, + WINDOW_OFFSET + TILE_SIZE * w, WINDOW_OFFSET + TILE_SIZE * y, + ink); + + /* + * Barriers. + */ + for (y = 0; y <= h; y++) + for (x = 0; x <= w; x++) { + int b = barrier(state, x % w, y % h); + if (x < w && (b & U)) + draw_rect(dr, WINDOW_OFFSET + TILE_SIZE * x - TILE_SIZE/24, + WINDOW_OFFSET + TILE_SIZE * y - TILE_SIZE/24, + TILE_SIZE + TILE_SIZE/24 * 2, TILE_SIZE/24 * 2, ink); + if (y < h && (b & L)) + draw_rect(dr, WINDOW_OFFSET + TILE_SIZE * x - TILE_SIZE/24, + WINDOW_OFFSET + TILE_SIZE * y - TILE_SIZE/24, + TILE_SIZE/24 * 2, TILE_SIZE + TILE_SIZE/24 * 2, ink); + } + + /* + * Grid contents. + */ + for (y = 0; y < h; y++) + for (x = 0; x < w; x++) { + int vx, v = tile(state, x, y); + int locked = v & LOCKED; + + v &= 0xF; + + /* + * Rotate into a standard orientation for the top left + * corner diagram. + */ + vx = v; + while (vx != 0 && vx != 15 && vx != 1 && vx != 9 && vx != 13 && + vx != 5) + vx = A(vx); + + /* + * Draw the top left corner diagram. + */ + draw_diagram(dr, ds, x, y, TRUE, vx, TRUE, ink); + + /* + * Draw the real solution diagram, if we're doing so. + */ + draw_diagram(dr, ds, x, y, FALSE, v, locked, ink); + } } +#ifdef COMBINED +#define thegame net #endif + +const struct game thegame = { + "Net", "games.net", "net", + default_params, + game_fetch_preset, NULL, + decode_params, + encode_params, + free_params, + dup_params, + TRUE, game_configure, custom_params, + validate_params, + new_game_desc, + validate_desc, + new_game, + dup_game, + free_game, + TRUE, solve_game, + FALSE, game_can_format_as_text_now, game_text_format, + new_ui, + free_ui, + encode_ui, + decode_ui, + game_changed_state, + interpret_move, + execute_move, + PREFERRED_TILE_SIZE, game_compute_size, game_set_size, + game_colours, + game_new_drawstate, + game_free_drawstate, + game_redraw, + game_anim_length, + game_flash_length, + game_status, + TRUE, FALSE, game_print_size, game_print, + TRUE, /* wants_statusbar */ + FALSE, game_timing_state, + 0, /* flags */ +};