2 * flip.c: Puzzle involving lighting up all the squares on a grid,
3 * where each click toggles an overlapping set of lights.
9 * - `Solve' could mark the squares you must click to solve
10 * + infrastructure change: this would mean the Solve operation
11 * must receive the current game_state as well as the initial
12 * one, which I've been wondering about for a while
34 #define PREFERRED_TILE_SIZE 48
35 #define TILE_SIZE (ds->tilesize)
36 #define BORDER (TILE_SIZE / 2)
37 #define COORD(x) ( (x) * TILE_SIZE + BORDER )
38 #define FROMCOORD(x) ( ((x) - BORDER + TILE_SIZE) / TILE_SIZE - 1 )
40 #define ANIM_TIME 0.25F
41 #define FLASH_FRAME 0.07F
44 * Possible ways to decide which lights are toggled by each click.
45 * Essentially, each of these describes a means of inventing a
58 * This structure is shared between all the game_states describing
59 * a particular game, so it's reference-counted.
63 unsigned char *matrix; /* array of (w*h) by (w*h) */
69 unsigned char *grid; /* array of w*h */
70 struct matrix *matrix;
73 static game_params *default_params(void)
75 game_params *ret = snew(game_params);
78 ret->matrix_type = CROSSES;
83 static const struct game_params flip_presets[] = {
92 static int game_fetch_preset(int i, char **name, game_params **params)
97 if (i < 0 || i >= lenof(flip_presets))
100 ret = snew(game_params);
101 *ret = flip_presets[i];
103 sprintf(str, "%dx%d %s", ret->w, ret->h,
104 ret->matrix_type == CROSSES ? "Crosses" : "Random");
111 static void free_params(game_params *params)
116 static game_params *dup_params(game_params *params)
118 game_params *ret = snew(game_params);
119 *ret = *params; /* structure copy */
123 static void decode_params(game_params *ret, char const *string)
125 ret->w = ret->h = atoi(string);
126 while (*string && isdigit(*string)) string++;
127 if (*string == 'x') {
129 ret->h = atoi(string);
130 while (*string && isdigit(*string)) string++;
132 if (*string == 'r') {
134 ret->matrix_type = RANDOM;
135 } else if (*string == 'c') {
137 ret->matrix_type = CROSSES;
141 static char *encode_params(game_params *params, int full)
145 sprintf(data, "%dx%d%s", params->w, params->h,
146 !full ? "" : params->matrix_type == CROSSES ? "c" : "r");
151 static config_item *game_configure(game_params *params)
153 config_item *ret = snewn(4, config_item);
156 ret[0].name = "Width";
157 ret[0].type = C_STRING;
158 sprintf(buf, "%d", params->w);
159 ret[0].sval = dupstr(buf);
162 ret[1].name = "Height";
163 ret[1].type = C_STRING;
164 sprintf(buf, "%d", params->h);
165 ret[1].sval = dupstr(buf);
168 ret[2].name = "Shape type";
169 ret[2].type = C_CHOICES;
170 ret[2].sval = ":Crosses:Random";
171 ret[2].ival = params->matrix_type;
181 static game_params *custom_params(config_item *cfg)
183 game_params *ret = snew(game_params);
185 ret->w = atoi(cfg[0].sval);
186 ret->h = atoi(cfg[1].sval);
187 ret->matrix_type = cfg[2].ival;
192 static char *validate_params(game_params *params)
194 if (params->w <= 0 || params->h <= 0)
195 return "Width and height must both be greater than zero";
199 static char *encode_bitmap(unsigned char *bmp, int len)
201 int slen = (len + 3) / 4;
205 ret = snewn(slen + 1, char);
206 for (i = 0; i < slen; i++) {
209 for (j = 0; j < 4; j++)
210 if (i*4+j < len && bmp[i*4+j])
212 ret[i] = "0123456789abcdef"[v];
218 static void decode_bitmap(unsigned char *bmp, int len, char *hex)
220 int slen = (len + 3) / 4;
223 for (i = 0; i < slen; i++) {
224 int j, v, c = hex[i];
225 if (c >= '0' && c <= '9')
227 else if (c >= 'A' && c <= 'F')
229 else if (c >= 'a' && c <= 'f')
232 v = 0; /* shouldn't happen */
233 for (j = 0; j < 4; j++) {
245 * Structure used during random matrix generation, and a compare
246 * function to permit storage in a tree234.
249 int cx, cy; /* coords of click square */
250 int x, y; /* coords of output square */
252 * Number of click squares which currently affect this output
257 * Number of output squares currently affected by this click
262 #define SORT(field) do { \
263 if (a->field < b->field) \
265 else if (a->field > b->field) \
269 * Compare function for choosing the next square to add. We must
270 * sort by coverage, then by omino size, then everything else.
272 static int sqcmp_pick(void *av, void *bv)
274 struct sq *a = (struct sq *)av;
275 struct sq *b = (struct sq *)bv;
285 * Compare function for adjusting the coverage figures after a
286 * change. We sort first by coverage and output square, then by
289 static int sqcmp_cov(void *av, void *bv)
291 struct sq *a = (struct sq *)av;
292 struct sq *b = (struct sq *)bv;
302 * Compare function for adjusting the omino sizes after a change.
303 * We sort first by omino size and input square, then by everything
306 static int sqcmp_osize(void *av, void *bv)
308 struct sq *a = (struct sq *)av;
309 struct sq *b = (struct sq *)bv;
318 static void addsq(tree234 *t, int w, int h, int cx, int cy,
319 int x, int y, unsigned char *matrix)
325 if (x < 0 || x >= w || y < 0 || y >= h)
327 if (abs(x-cx) > 1 || abs(y-cy) > 1)
329 if (matrix[(cy*w+cx) * wh + y*w+x])
332 sq = snew(struct sq);
337 sq->coverage = sq->ominosize = 0;
338 for (i = 0; i < wh; i++) {
339 if (matrix[i * wh + y*w+x])
341 if (matrix[(cy*w+cx) * wh + i])
345 if (add234(t, sq) != sq)
346 sfree(sq); /* already there */
348 static void addneighbours(tree234 *t, int w, int h, int cx, int cy,
349 int x, int y, unsigned char *matrix)
351 addsq(t, w, h, cx, cy, x-1, y, matrix);
352 addsq(t, w, h, cx, cy, x+1, y, matrix);
353 addsq(t, w, h, cx, cy, x, y-1, matrix);
354 addsq(t, w, h, cx, cy, x, y+1, matrix);
357 static char *new_game_desc(game_params *params, random_state *rs,
358 game_aux_info **aux, int interactive)
360 int w = params->w, h = params->h, wh = w * h;
362 unsigned char *matrix, *grid;
363 char *mbmp, *gbmp, *ret;
365 matrix = snewn(wh * wh, unsigned char);
366 grid = snewn(wh, unsigned char);
369 * First set up the matrix.
371 switch (params->matrix_type) {
373 for (i = 0; i < wh; i++) {
374 int ix = i % w, iy = i / w;
375 for (j = 0; j < wh; j++) {
376 int jx = j % w, jy = j / w;
377 if (abs(jx - ix) + abs(jy - iy) <= 1)
386 tree234 *pick, *cov, *osize;
389 pick = newtree234(sqcmp_pick);
390 cov = newtree234(sqcmp_cov);
391 osize = newtree234(sqcmp_osize);
393 memset(matrix, 0, wh * wh);
394 for (i = 0; i < wh; i++) {
398 for (i = 0; i < wh; i++) {
399 int ix = i % w, iy = i / w;
400 addneighbours(pick, w, h, ix, iy, ix, iy, matrix);
401 addneighbours(cov, w, h, ix, iy, ix, iy, matrix);
402 addneighbours(osize, w, h, ix, iy, ix, iy, matrix);
406 * Repeatedly choose a square to add to the matrix,
407 * until we have enough. I'll arbitrarily choose our
408 * limit to be the same as the total number of set bits
409 * in the crosses matrix.
411 limit = 4*wh - 2*(w+h); /* centre squares already present */
413 while (limit-- > 0) {
414 struct sq *sq, *sq2, sqlocal;
418 * Find the lowest element in the pick tree.
420 sq = index234(pick, 0);
423 * Find the highest element with the same coverage
424 * and omino size, by setting all other elements to
428 sqlocal.cx = sqlocal.cy = sqlocal.x = sqlocal.y = wh;
429 sq = findrelpos234(pick, &sqlocal, NULL, REL234_LT, &k);
433 * Pick at random from all elements up to k of the
436 k = random_upto(rs, k+1);
437 sq = delpos234(pick, k);
442 * Add this square to the matrix.
444 matrix[(sq->cy * w + sq->cx) * wh + (sq->y * w + sq->x)] = 1;
447 * Correct the matrix coverage field of any sq
448 * which points at this output square.
451 sqlocal.cx = sqlocal.cy = sqlocal.ominosize = -1;
452 while ((sq2 = findrel234(cov, &sqlocal, NULL,
453 REL234_GT)) != NULL &&
454 sq2->coverage == sq->coverage &&
455 sq2->x == sq->x && sq2->y == sq->y) {
466 * Correct the omino size field of any sq which
467 * points at this input square.
470 sqlocal.x = sqlocal.y = sqlocal.coverage = -1;
471 while ((sq2 = findrel234(osize, &sqlocal, NULL,
472 REL234_GT)) != NULL &&
473 sq2->ominosize == sq->ominosize &&
474 sq2->cx == sq->cx && sq2->cy == sq->cy) {
485 * The sq we actually picked out of the tree is
486 * finished with; but its neighbours now need to
489 addneighbours(pick, w,h, sq->cx,sq->cy, sq->x,sq->y, matrix);
490 addneighbours(cov, w,h, sq->cx,sq->cy, sq->x,sq->y, matrix);
491 addneighbours(osize, w,h, sq->cx,sq->cy, sq->x,sq->y, matrix);
496 * Free all remaining sq structures.
500 while ((sq = delpos234(pick, 0)) != NULL)
508 * Finally, check to see if any two matrix rows are
509 * exactly identical. If so, this is not an acceptable
510 * matrix, and we give up and go round again.
512 * I haven't been immediately able to think of a
513 * plausible means of algorithmically avoiding this
514 * situation (by, say, making a small perturbation to
515 * an offending matrix), so for the moment I'm just
516 * going to deal with it by throwing the whole thing
517 * away. I suspect this will lead to scalability
518 * problems (since most of the things happening in
519 * these matrices are local, the chance of _some_
520 * neighbourhood having two identical regions will
521 * increase with the grid area), but so far this puzzle
522 * seems to be really hard at large sizes so I'm not
523 * massively worried yet. Anyone needs this done
524 * better, they're welcome to submit a patch.
526 for (i = 0; i < wh; i++) {
527 for (j = 0; j < wh; j++)
529 !memcmp(matrix + i * wh, matrix + j * wh, wh))
535 break; /* no matches found */
541 * Now invent a random initial set of lights.
543 * At first glance it looks as if it might be quite difficult
544 * to choose equiprobably from all soluble light sets. After
545 * all, soluble light sets are those in the image space of the
546 * transformation matrix; so first we'd have to identify that
547 * space and its dimension, then pick a random coordinate for
548 * each basis vector and recombine. Lot of fiddly matrix
551 * However, vector spaces are nicely orthogonal and relieve us
552 * of all that difficulty. For every point in the image space,
553 * there are precisely as many points in the input space that
554 * map to it as there are elements in the kernel of the
555 * transformation matrix (because adding any kernel element to
556 * the input does not change the output, and because any two
557 * inputs mapping to the same output must differ by an element
558 * of the kernel because that's what the kernel _is_); and
559 * these cosets are all disjoint (obviously, since no input
560 * point can map to more than one output point) and cover the
561 * whole space (equally obviously, because no input point can
562 * map to fewer than one output point!).
564 * So the input space contains the same number of points for
565 * each point in the output space; thus, we can simply choose
566 * equiprobably from elements of the _input_ space, and filter
567 * the result through the transformation matrix in the obvious
568 * way, and we thereby guarantee to choose equiprobably from
569 * all the output points. Phew!
573 for (i = 0; i < wh; i++) {
574 int v = random_upto(rs, 2);
576 for (j = 0; j < wh; j++)
577 grid[j] ^= matrix[i*wh+j];
581 * Ensure we don't have the starting state already!
583 for (i = 0; i < wh; i++)
591 * Now encode the matrix and the starting grid as a game
592 * description. We'll do this by concatenating two great big
595 mbmp = encode_bitmap(matrix, wh*wh);
596 gbmp = encode_bitmap(grid, wh);
597 ret = snewn(strlen(mbmp) + strlen(gbmp) + 2, char);
598 sprintf(ret, "%s,%s", mbmp, gbmp);
604 static void game_free_aux_info(game_aux_info *aux)
606 assert(!"Shouldn't happen");
609 static char *validate_desc(game_params *params, char *desc)
611 int w = params->w, h = params->h, wh = w * h;
612 int mlen = (wh*wh+3)/4, glen = (wh+3)/4;
614 if (strspn(desc, "0123456789abcdefABCDEF") != mlen)
615 return "Matrix description is wrong length";
616 if (desc[mlen] != ',')
617 return "Expected comma after matrix description";
618 if (strspn(desc+mlen+1, "0123456789abcdefABCDEF") != glen)
619 return "Grid description is wrong length";
620 if (desc[mlen+1+glen])
621 return "Unexpected data after grid description";
626 static game_state *new_game(midend_data *me, game_params *params, char *desc)
628 int w = params->w, h = params->h, wh = w * h;
629 int mlen = (wh*wh+3)/4;
631 game_state *state = snew(game_state);
635 state->completed = FALSE;
637 state->matrix = snew(struct matrix);
638 state->matrix->refcount = 1;
639 state->matrix->matrix = snewn(wh*wh, unsigned char);
640 decode_bitmap(state->matrix->matrix, wh*wh, desc);
641 state->grid = snewn(wh, unsigned char);
642 decode_bitmap(state->grid, wh, desc + mlen + 1);
647 static game_state *dup_game(game_state *state)
649 game_state *ret = snew(game_state);
653 ret->completed = state->completed;
654 ret->moves = state->moves;
655 ret->matrix = state->matrix;
656 state->matrix->refcount++;
657 ret->grid = snewn(ret->w * ret->h, unsigned char);
658 memcpy(ret->grid, state->grid, ret->w * ret->h);
663 static void free_game(game_state *state)
666 if (--state->matrix->refcount <= 0) {
667 sfree(state->matrix->matrix);
668 sfree(state->matrix);
673 static game_state *solve_game(game_state *state, game_aux_info *aux,
679 static char *game_text_format(game_state *state)
684 static game_ui *new_ui(game_state *state)
689 static void free_ui(game_ui *ui)
693 static void game_changed_state(game_ui *ui, game_state *oldstate,
694 game_state *newstate)
698 struct game_drawstate {
700 unsigned char *tiles;
704 static game_state *make_move(game_state *from, game_ui *ui, game_drawstate *ds,
705 int x, int y, int button)
707 int w = from->w, h = from->h, wh = w * h;
710 if (button == LEFT_BUTTON) {
711 int tx = FROMCOORD(x), ty = FROMCOORD(y);
712 if (tx >= 0 && tx < w && ty >= 0 && ty < h) {
715 ret = dup_game(from);
723 for (j = 0; j < wh; j++) {
724 ret->grid[j] ^= ret->matrix->matrix[i*wh+j];
725 if (ret->grid[j] & 1)
729 ret->completed = TRUE;
738 /* ----------------------------------------------------------------------
742 static void game_size(game_params *params, game_drawstate *ds,
743 int *x, int *y, int expand)
747 * Each window dimension equals the tile size times one more
748 * than the grid dimension (the border is half the width of the
751 tsx = *x / (params->w + 1);
752 tsy = *y / (params->h + 1);
757 ds->tilesize = min(ts, PREFERRED_TILE_SIZE);
759 *x = TILE_SIZE * params->w + 2 * BORDER;
760 *y = TILE_SIZE * params->h + 2 * BORDER;
763 static float *game_colours(frontend *fe, game_state *state, int *ncolours)
765 float *ret = snewn(3 * NCOLOURS, float);
767 frontend_default_colour(fe, &ret[COL_BACKGROUND * 3]);
769 ret[COL_WRONG * 3 + 0] = ret[COL_BACKGROUND * 3 + 0] / 3;
770 ret[COL_WRONG * 3 + 1] = ret[COL_BACKGROUND * 3 + 1] / 3;
771 ret[COL_WRONG * 3 + 2] = ret[COL_BACKGROUND * 3 + 2] / 3;
773 ret[COL_RIGHT * 3 + 0] = 1.0F;
774 ret[COL_RIGHT * 3 + 1] = 1.0F;
775 ret[COL_RIGHT * 3 + 2] = 1.0F;
777 ret[COL_GRID * 3 + 0] = ret[COL_BACKGROUND * 3 + 0] / 1.5F;
778 ret[COL_GRID * 3 + 1] = ret[COL_BACKGROUND * 3 + 1] / 1.5F;
779 ret[COL_GRID * 3 + 2] = ret[COL_BACKGROUND * 3 + 2] / 1.5F;
781 ret[COL_DIAG * 3 + 0] = ret[COL_GRID * 3 + 0];
782 ret[COL_DIAG * 3 + 1] = ret[COL_GRID * 3 + 1];
783 ret[COL_DIAG * 3 + 2] = ret[COL_GRID * 3 + 2];
785 *ncolours = NCOLOURS;
789 static game_drawstate *game_new_drawstate(game_state *state)
791 struct game_drawstate *ds = snew(struct game_drawstate);
797 ds->tiles = snewn(ds->w*ds->h, unsigned char);
798 ds->tilesize = 0; /* haven't decided yet */
799 for (i = 0; i < ds->w*ds->h; i++)
805 static void game_free_drawstate(game_drawstate *ds)
811 static void draw_tile(frontend *fe, game_drawstate *ds,
812 game_state *state, int x, int y, int tile, int anim,
815 int w = ds->w, h = ds->h, wh = w * h;
816 int bx = x * TILE_SIZE + BORDER, by = y * TILE_SIZE + BORDER;
819 clip(fe, bx+1, by+1, TILE_SIZE-1, TILE_SIZE-1);
821 draw_rect(fe, bx+1, by+1, TILE_SIZE-1, TILE_SIZE-1,
822 anim ? COL_BACKGROUND : tile & 1 ? COL_WRONG : COL_RIGHT);
825 * Draw a polygon indicating that the square is diagonally
828 int coords[8], colour;
830 coords[0] = bx + TILE_SIZE;
832 coords[2] = bx + TILE_SIZE * animtime;
833 coords[3] = by + TILE_SIZE * animtime;
835 coords[5] = by + TILE_SIZE;
836 coords[6] = bx + TILE_SIZE - TILE_SIZE * animtime;
837 coords[7] = by + TILE_SIZE - TILE_SIZE * animtime;
839 colour = (tile & 1 ? COL_WRONG : COL_RIGHT);
841 colour = COL_WRONG + COL_RIGHT - colour;
843 draw_polygon(fe, coords, 4, TRUE, colour);
844 draw_polygon(fe, coords, 4, FALSE, COL_GRID);
848 * Draw a little diagram in the tile which indicates which
849 * surrounding tiles flip when this one is clicked.
851 for (i = 0; i < h; i++)
852 for (j = 0; j < w; j++)
853 if (state->matrix->matrix[(y*w+x)*wh + i*w+j]) {
854 int ox = j - x, oy = i - y;
855 int td = TILE_SIZE / 16;
856 int cx = (bx + TILE_SIZE/2) + (2 * ox - 1) * td;
857 int cy = (by + TILE_SIZE/2) + (2 * oy - 1) * td;
858 if (ox == 0 && oy == 0)
859 draw_rect(fe, cx, cy, 2*td+1, 2*td+1, COL_DIAG);
861 draw_line(fe, cx, cy, cx+2*td, cy, COL_DIAG);
862 draw_line(fe, cx, cy+2*td, cx+2*td, cy+2*td, COL_DIAG);
863 draw_line(fe, cx, cy, cx, cy+2*td, COL_DIAG);
864 draw_line(fe, cx+2*td, cy, cx+2*td, cy+2*td, COL_DIAG);
870 draw_update(fe, bx+1, by+1, TILE_SIZE-1, TILE_SIZE-1);
873 static void game_redraw(frontend *fe, game_drawstate *ds, game_state *oldstate,
874 game_state *state, int dir, game_ui *ui,
875 float animtime, float flashtime)
877 int w = ds->w, h = ds->h, wh = w * h;
881 draw_rect(fe, 0, 0, TILE_SIZE * w + 2 * BORDER,
882 TILE_SIZE * h + 2 * BORDER, COL_BACKGROUND);
885 * Draw the grid lines.
887 for (i = 0; i <= w; i++)
888 draw_line(fe, i * TILE_SIZE + BORDER, BORDER,
889 i * TILE_SIZE + BORDER, h * TILE_SIZE + BORDER,
891 for (i = 0; i <= h; i++)
892 draw_line(fe, BORDER, i * TILE_SIZE + BORDER,
893 w * TILE_SIZE + BORDER, i * TILE_SIZE + BORDER,
896 draw_update(fe, 0, 0, TILE_SIZE * w + 2 * BORDER,
897 TILE_SIZE * h + 2 * BORDER);
903 flashframe = flashtime / FLASH_FRAME;
907 animtime /= ANIM_TIME; /* scale it so it goes from 0 to 1 */
909 for (i = 0; i < wh; i++) {
910 int x = i % w, y = i / w;
912 int v = state->grid[i];
915 if (flashframe >= 0) {
916 fx = (w+1)/2 - min(x+1, w-x);
917 fy = (h+1)/2 - min(y+1, h-y);
919 if (fd == flashframe)
921 else if (fd == flashframe - 1)
925 if (oldstate && state->grid[i] != oldstate->grid[i])
926 vv = 255; /* means `animated' */
930 if (ds->tiles[i] == 255 || vv == 255 || ds->tiles[i] != vv) {
931 draw_tile(fe, ds, state, x, y, v, vv == 255, animtime);
939 sprintf(buf, "%sMoves: %d", state->completed ? "COMPLETED! " : "",
946 static float game_anim_length(game_state *oldstate, game_state *newstate,
947 int dir, game_ui *ui)
952 static float game_flash_length(game_state *oldstate, game_state *newstate,
953 int dir, game_ui *ui)
955 if (!oldstate->completed && newstate->completed)
956 return FLASH_FRAME * (max((newstate->w+1)/2, (newstate->h+1)/2)+1);
961 static int game_wants_statusbar(void)
966 static int game_timing_state(game_state *state)
975 const struct game thegame = {
983 TRUE, game_configure, custom_params,
992 FALSE, game_text_format,
1000 game_free_drawstate,
1004 game_wants_statusbar,
1005 FALSE, game_timing_state,
1006 0, /* mouse_priorities */