-
Notifications
You must be signed in to change notification settings - Fork 6
/
Copy pathpegs.c
1358 lines (1178 loc) · 35.1 KB
/
pegs.c
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
690
691
692
693
694
695
696
697
698
699
700
701
702
703
704
705
706
707
708
709
710
711
712
713
714
715
716
717
718
719
720
721
722
723
724
725
726
727
728
729
730
731
732
733
734
735
736
737
738
739
740
741
742
743
744
745
746
747
748
749
750
751
752
753
754
755
756
757
758
759
760
761
762
763
764
765
766
767
768
769
770
771
772
773
774
775
776
777
778
779
780
781
782
783
784
785
786
787
788
789
790
791
792
793
794
795
796
797
798
799
800
801
802
803
804
805
806
807
808
809
810
811
812
813
814
815
816
817
818
819
820
821
822
823
824
825
826
827
828
829
830
831
832
833
834
835
836
837
838
839
840
841
842
843
844
845
846
847
848
849
850
851
852
853
854
855
856
857
858
859
860
861
862
863
864
865
866
867
868
869
870
871
872
873
874
875
876
877
878
879
880
881
882
883
884
885
886
887
888
889
890
891
892
893
894
895
896
897
898
899
900
901
902
903
904
905
906
907
908
909
910
911
912
913
914
915
916
917
918
919
920
921
922
923
924
925
926
927
928
929
930
931
932
933
934
935
936
937
938
939
940
941
942
943
944
945
946
947
948
949
950
951
952
953
954
955
956
957
958
959
960
961
962
963
964
965
966
967
968
969
970
971
972
973
974
975
976
977
978
979
980
981
982
983
984
985
986
987
988
989
990
991
992
993
994
995
996
997
998
999
1000
/*
* pegs.c: the classic Peg Solitaire game.
*/
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <assert.h>
#include <ctype.h>
#include <math.h>
#include "puzzles.h"
#include "tree234.h"
#define GRID_HOLE 0
#define GRID_PEG 1
#define GRID_OBST 2
#define GRID_CURSOR 10
#define GRID_JUMPING 20
enum {
COL_BACKGROUND,
COL_HIGHLIGHT,
COL_LOWLIGHT,
COL_PEG,
COL_CURSOR,
NCOLOURS
};
/*
* Grid shapes. I do some macro ickery here to ensure that my enum
* and the various forms of my name list always match up.
*/
#define TYPELIST(A) \
A(CROSS,Cross,cross) \
A(OCTAGON,Octagon,octagon) \
A(RANDOM,Random,random)
#define ENUM(upper,title,lower) TYPE_ ## upper,
#define TITLE(upper,title,lower) #title,
#define LOWER(upper,title,lower) #lower,
#define CONFIG(upper,title,lower) ":" #title
enum { TYPELIST(ENUM) TYPECOUNT };
static char const *const pegs_titletypes[] = { TYPELIST(TITLE) };
static char const *const pegs_lowertypes[] = { TYPELIST(LOWER) };
#define TYPECONFIG TYPELIST(CONFIG)
#define FLASH_FRAME 0.13F
struct game_params {
int w, h;
int type;
};
struct game_state {
int w, h;
bool completed;
unsigned char *grid;
};
static game_params *default_params(void)
{
game_params *ret = snew(game_params);
ret->w = ret->h = 7;
ret->type = TYPE_CROSS;
return ret;
}
static const struct game_params pegs_presets[] = {
{7, 7, TYPE_CROSS},
{7, 7, TYPE_OCTAGON},
{5, 5, TYPE_RANDOM},
{7, 7, TYPE_RANDOM},
{9, 9, TYPE_RANDOM},
};
static bool game_fetch_preset(int i, char **name, game_params **params)
{
game_params *ret;
char str[80];
if (i < 0 || i >= lenof(pegs_presets))
return false;
ret = snew(game_params);
*ret = pegs_presets[i];
strcpy(str, pegs_titletypes[ret->type]);
if (ret->type == TYPE_RANDOM)
sprintf(str + strlen(str), " %dx%d", ret->w, ret->h);
*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 *params, char const *string)
{
char const *p = string;
int i;
params->w = atoi(p);
while (*p && isdigit((unsigned char)*p)) p++;
if (*p == 'x') {
p++;
params->h = atoi(p);
while (*p && isdigit((unsigned char)*p)) p++;
} else {
params->h = params->w;
}
for (i = 0; i < lenof(pegs_lowertypes); i++)
if (!strcmp(p, pegs_lowertypes[i]))
params->type = i;
}
static char *encode_params(const game_params *params, bool full)
{
char str[80];
sprintf(str, "%dx%d", params->w, params->h);
if (full) {
assert(params->type >= 0 && params->type < lenof(pegs_lowertypes));
strcat(str, pegs_lowertypes[params->type]);
}
return dupstr(str);
}
static config_item *game_configure(const game_params *params)
{
config_item *ret = snewn(4, config_item);
char buf[80];
ret[0].name = "Width";
ret[0].type = C_STRING;
sprintf(buf, "%d", params->w);
ret[0].u.string.sval = dupstr(buf);
ret[1].name = "Height";
ret[1].type = C_STRING;
sprintf(buf, "%d", params->h);
ret[1].u.string.sval = dupstr(buf);
ret[2].name = "Board type";
ret[2].type = C_CHOICES;
ret[2].u.choices.choicenames = TYPECONFIG;
ret[2].u.choices.selected = params->type;
ret[3].name = NULL;
ret[3].type = C_END;
return ret;
}
static game_params *custom_params(const config_item *cfg)
{
game_params *ret = snew(game_params);
ret->w = atoi(cfg[0].u.string.sval);
ret->h = atoi(cfg[1].u.string.sval);
ret->type = cfg[2].u.choices.selected;
return ret;
}
static const char *validate_params(const game_params *params, bool full)
{
if (full && (params->w <= 3 || params->h <= 3))
return "Width and height must both be greater than three";
/*
* It might be possible to implement generalisations of Cross
* and Octagon, but only if I can find a proof that they're all
* soluble. For the moment, therefore, I'm going to disallow
* them at any size other than the standard one.
*/
if (full && (params->type == TYPE_CROSS || params->type == TYPE_OCTAGON)) {
if (params->w != 7 || params->h != 7)
return "This board type is only supported at 7x7";
}
return NULL;
}
/* ----------------------------------------------------------------------
* Beginning of code to generate random Peg Solitaire boards.
*
* This procedure is done with no aesthetic judgment, no effort at
* symmetry, no difficulty grading and generally no finesse
* whatsoever. We simply begin with an empty board containing a
* single peg, and repeatedly make random reverse moves until it's
* plausibly full. This typically yields a scrappy haphazard mess
* with several holes, an uneven shape, and no redeeming features
* except guaranteed solubility.
*
* My only concessions to sophistication are (a) to repeat the
* generation process until I at least get a grid that touches
* every edge of the specified board size, and (b) to try when
* selecting moves to reuse existing space rather than expanding
* into new space (so that non-rectangular board shape becomes a
* factor during play).
*/
struct move {
/*
* x,y are the start point of the move during generation (hence
* its endpoint during normal play).
*
* dx,dy are the direction of the move during generation.
* Absolute value 1. Hence, for example, x=3,y=5,dx=1,dy=0
* means that the move during generation starts at (3,5) and
* ends at (5,5), and vice versa during normal play.
*/
int x, y, dx, dy;
/*
* cost is 0, 1 or 2, depending on how many GRID_OBSTs we must
* turn into GRID_HOLEs to play this move.
*/
int cost;
};
static int movecmp(void *av, void *bv)
{
struct move *a = (struct move *)av;
struct move *b = (struct move *)bv;
if (a->y < b->y)
return -1;
else if (a->y > b->y)
return +1;
if (a->x < b->x)
return -1;
else if (a->x > b->x)
return +1;
if (a->dy < b->dy)
return -1;
else if (a->dy > b->dy)
return +1;
if (a->dx < b->dx)
return -1;
else if (a->dx > b->dx)
return +1;
return 0;
}
static int movecmpcost(void *av, void *bv)
{
struct move *a = (struct move *)av;
struct move *b = (struct move *)bv;
if (a->cost < b->cost)
return -1;
else if (a->cost > b->cost)
return +1;
return movecmp(av, bv);
}
struct movetrees {
tree234 *bymove, *bycost;
};
static void update_moves(unsigned char *grid, int w, int h, int x, int y,
struct movetrees *trees)
{
struct move move;
int dir, pos;
/*
* There are twelve moves that can include (x,y): three in each
* of four directions. Check each one to see if it's possible.
*/
for (dir = 0; dir < 4; dir++) {
int dx, dy;
if (dir & 1)
dx = 0, dy = dir - 2;
else
dy = 0, dx = dir - 1;
assert(abs(dx) + abs(dy) == 1);
for (pos = 0; pos < 3; pos++) {
int v1, v2, v3;
move.dx = dx;
move.dy = dy;
move.x = x - pos*dx;
move.y = y - pos*dy;
if (move.x < 0 || move.x >= w || move.y < 0 || move.y >= h)
continue; /* completely invalid move */
if (move.x+2*move.dx < 0 || move.x+2*move.dx >= w ||
move.y+2*move.dy < 0 || move.y+2*move.dy >= h)
continue; /* completely invalid move */
v1 = grid[move.y * w + move.x];
v2 = grid[(move.y+move.dy) * w + (move.x+move.dx)];
v3 = grid[(move.y+2*move.dy)*w + (move.x+2*move.dx)];
if (v1 == GRID_PEG && v2 != GRID_PEG && v3 != GRID_PEG) {
struct move *m;
move.cost = (v2 == GRID_OBST) + (v3 == GRID_OBST);
/*
* This move is possible. See if it's already in
* the tree.
*/
m = find234(trees->bymove, &move, NULL);
if (m && m->cost != move.cost) {
/*
* It's in the tree but listed with the wrong
* cost. Remove the old version.
*/
#ifdef GENERATION_DIAGNOSTICS
printf("correcting %d%+d,%d%+d at cost %d\n",
m->x, m->dx, m->y, m->dy, m->cost);
#endif
del234(trees->bymove, m);
del234(trees->bycost, m);
sfree(m);
m = NULL;
}
if (!m) {
struct move *m, *m2;
m = snew(struct move);
*m = move;
m2 = add234(trees->bymove, m);
m2 = add234(trees->bycost, m);
assert(m2 == m);
#ifdef GENERATION_DIAGNOSTICS
printf("adding %d%+d,%d%+d at cost %d\n",
move.x, move.dx, move.y, move.dy, move.cost);
#endif
} else {
#ifdef GENERATION_DIAGNOSTICS
printf("not adding %d%+d,%d%+d at cost %d\n",
move.x, move.dx, move.y, move.dy, move.cost);
#endif
}
} else {
/*
* This move is impossible. If it is already in the
* tree, delete it.
*
* (We make use here of the fact that del234
* doesn't have to be passed a pointer to the
* _actual_ element it's deleting: it merely needs
* one that compares equal to it, and it will
* return the one it deletes.)
*/
struct move *m = del234(trees->bymove, &move);
#ifdef GENERATION_DIAGNOSTICS
printf("%sdeleting %d%+d,%d%+d\n", m ? "" : "not ",
move.x, move.dx, move.y, move.dy);
#endif
if (m) {
del234(trees->bycost, m);
sfree(m);
}
}
}
}
}
static void pegs_genmoves(unsigned char *grid, int w, int h, random_state *rs)
{
struct movetrees atrees, *trees = &atrees;
struct move *m;
int x, y, i, nmoves;
trees->bymove = newtree234(movecmp);
trees->bycost = newtree234(movecmpcost);
for (y = 0; y < h; y++)
for (x = 0; x < w; x++)
if (grid[y*w+x] == GRID_PEG)
update_moves(grid, w, h, x, y, trees);
nmoves = 0;
while (1) {
int limit, maxcost, index;
struct move mtmp, move, *m;
/*
* See how many moves we can make at zero cost. Make one,
* if possible. Failing that, make a one-cost move, and
* then a two-cost one.
*
* After filling at least half the input grid, we no longer
* accept cost-2 moves: if that's our only option, we give
* up and finish.
*/
mtmp.y = h+1;
maxcost = (nmoves < w*h/2 ? 2 : 1);
m = NULL; /* placate optimiser */
for (mtmp.cost = 0; mtmp.cost <= maxcost; mtmp.cost++) {
limit = -1;
m = findrelpos234(trees->bycost, &mtmp, NULL, REL234_LT, &limit);
#ifdef GENERATION_DIAGNOSTICS
printf("%d moves available with cost %d\n", limit+1, mtmp.cost);
#endif
if (m)
break;
}
if (!m)
break;
index = random_upto(rs, limit+1);
move = *(struct move *)index234(trees->bycost, index);
#ifdef GENERATION_DIAGNOSTICS
printf("selecting move %d%+d,%d%+d at cost %d\n",
move.x, move.dx, move.y, move.dy, move.cost);
#endif
grid[move.y * w + move.x] = GRID_HOLE;
grid[(move.y+move.dy) * w + (move.x+move.dx)] = GRID_PEG;
grid[(move.y+2*move.dy)*w + (move.x+2*move.dx)] = GRID_PEG;
for (i = 0; i <= 2; i++) {
int tx = move.x + i*move.dx;
int ty = move.y + i*move.dy;
update_moves(grid, w, h, tx, ty, trees);
}
nmoves++;
}
while ((m = delpos234(trees->bymove, 0)) != NULL) {
del234(trees->bycost, m);
sfree(m);
}
freetree234(trees->bymove);
freetree234(trees->bycost);
}
static void pegs_generate(unsigned char *grid, int w, int h, random_state *rs)
{
while (1) {
int x, y, extremes;
memset(grid, GRID_OBST, w*h);
grid[(h/2) * w + (w/2)] = GRID_PEG;
#ifdef GENERATION_DIAGNOSTICS
printf("beginning move selection\n");
#endif
pegs_genmoves(grid, w, h, rs);
#ifdef GENERATION_DIAGNOSTICS
printf("finished move selection\n");
#endif
extremes = 0;
for (y = 0; y < h; y++) {
if (grid[y*w+0] != GRID_OBST)
extremes |= 1;
if (grid[y*w+w-1] != GRID_OBST)
extremes |= 2;
}
for (x = 0; x < w; x++) {
if (grid[0*w+x] != GRID_OBST)
extremes |= 4;
if (grid[(h-1)*w+x] != GRID_OBST)
extremes |= 8;
}
if (extremes == 15)
break;
#ifdef GENERATION_DIAGNOSTICS
printf("insufficient extent; trying again\n");
#endif
}
#ifdef GENERATION_DIAGNOSTICS
fflush(stdout);
#endif
}
/* ----------------------------------------------------------------------
* End of board generation code. Now for the client code which uses
* it as part of the puzzle.
*/
static char *new_game_desc(const game_params *params, random_state *rs,
char **aux, bool interactive)
{
int w = params->w, h = params->h;
unsigned char *grid;
char *ret;
int i;
grid = snewn(w*h, unsigned char);
if (params->type == TYPE_RANDOM) {
pegs_generate(grid, w, h, rs);
} else {
int x, y, cx, cy, v;
for (y = 0; y < h; y++)
for (x = 0; x < w; x++) {
v = GRID_OBST; /* placate optimiser */
switch (params->type) {
case TYPE_CROSS:
cx = abs(x - w/2);
cy = abs(y - h/2);
if (cx == 0 && cy == 0)
v = GRID_HOLE;
else if (cx > 1 && cy > 1)
v = GRID_OBST;
else
v = GRID_PEG;
break;
case TYPE_OCTAGON:
cx = abs(x - w/2);
cy = abs(y - h/2);
if (cx + cy > 1 + max(w,h)/2)
v = GRID_OBST;
else
v = GRID_PEG;
break;
}
grid[y*w+x] = v;
}
if (params->type == TYPE_OCTAGON) {
/*
* The octagonal (European) solitaire layout is
* actually _insoluble_ with the starting hole at the
* centre. Here's a proof:
*
* Colour the squares of the board diagonally in
* stripes of three different colours, which I'll call
* A, B and C. So the board looks like this:
*
* A B C
* A B C A B
* A B C A B C A
* B C A B C A B
* C A B C A B C
* B C A B C
* A B C
*
* Suppose we keep running track of the number of pegs
* occuping each colour of square. This colouring has
* the property that any valid move whatsoever changes
* all three of those counts by one (two of them go
* down and one goes up), which means that the _parity_
* of every count flips on every move.
*
* If the centre square starts off unoccupied, then
* there are twelve pegs on each colour and all three
* counts start off even; therefore, after 35 moves all
* three counts would have to be odd, which isn't
* possible if there's only one peg left. []
*
* This proof works just as well if the starting hole
* is _any_ of the thirteen positions labelled B. Also,
* we can stripe the board in the opposite direction
* and rule out any square labelled B in that colouring
* as well. This leaves:
*
* Y n Y
* n n Y n n
* Y n n Y n n Y
* n Y Y n Y Y n
* Y n n Y n n Y
* n n Y n n
* Y n Y
*
* where the ns are squares we've proved insoluble, and
* the Ys are the ones remaining.
*
* That doesn't prove all those starting positions to
* be soluble, of course; they're merely the ones we
* _haven't_ proved to be impossible. Nevertheless, it
* turns out that they are all soluble, so when the
* user requests an Octagon board the simplest thing is
* to pick one of these at random.
*
* Rather than picking equiprobably from those twelve
* positions, we'll pick equiprobably from the three
* equivalence classes
*/
switch (random_upto(rs, 3)) {
case 0:
/* Remove a random corner piece. */
{
int dx, dy;
dx = random_upto(rs, 2) * 2 - 1; /* +1 or -1 */
dy = random_upto(rs, 2) * 2 - 1; /* +1 or -1 */
if (random_upto(rs, 2))
dy *= 3;
else
dx *= 3;
grid[(3+dy)*w+(3+dx)] = GRID_HOLE;
}
break;
case 1:
/* Remove a random piece two from the centre. */
{
int dx, dy;
dx = 2 * (random_upto(rs, 2) * 2 - 1);
if (random_upto(rs, 2))
dy = 0;
else
dy = dx, dx = 0;
grid[(3+dy)*w+(3+dx)] = GRID_HOLE;
}
break;
default /* case 2 */:
/* Remove a random piece one from the centre. */
{
int dx, dy;
dx = random_upto(rs, 2) * 2 - 1;
if (random_upto(rs, 2))
dy = 0;
else
dy = dx, dx = 0;
grid[(3+dy)*w+(3+dx)] = GRID_HOLE;
}
break;
}
}
}
/*
* Encode a game description which is simply a long list of P
* for peg, H for hole or O for obstacle.
*/
ret = snewn(w*h+1, char);
for (i = 0; i < w*h; i++)
ret[i] = (grid[i] == GRID_PEG ? 'P' :
grid[i] == GRID_HOLE ? 'H' : 'O');
ret[w*h] = '\0';
sfree(grid);
return ret;
}
static const char *validate_desc(const game_params *params, const char *desc)
{
int len = params->w * params->h;
if (len != strlen(desc))
return "Game description is wrong length";
if (len != strspn(desc, "PHO"))
return "Invalid character in game description";
return NULL;
}
static game_state *new_game(midend *me, const game_params *params,
const char *desc)
{
int w = params->w, h = params->h;
game_state *state = snew(game_state);
int i;
state->w = w;
state->h = h;
state->completed = false;
state->grid = snewn(w*h, unsigned char);
for (i = 0; i < w*h; i++)
state->grid[i] = (desc[i] == 'P' ? GRID_PEG :
desc[i] == 'H' ? GRID_HOLE : GRID_OBST);
return state;
}
static game_state *dup_game(const game_state *state)
{
int w = state->w, h = state->h;
game_state *ret = snew(game_state);
ret->w = state->w;
ret->h = state->h;
ret->completed = state->completed;
ret->grid = snewn(w*h, unsigned char);
memcpy(ret->grid, state->grid, w*h);
return ret;
}
static void free_game(game_state *state)
{
sfree(state->grid);
sfree(state);
}
static char *solve_game(const game_state *state, const game_state *currstate,
const char *aux, const char **error)
{
return NULL;
}
static bool game_can_format_as_text_now(const game_params *params)
{
return true;
}
static char *game_text_format(const game_state *state)
{
int w = state->w, h = state->h;
int x, y;
char *ret;
ret = snewn((w+1)*h + 1, char);
for (y = 0; y < h; y++) {
for (x = 0; x < w; x++)
ret[y*(w+1)+x] = (state->grid[y*w+x] == GRID_HOLE ? '-' :
state->grid[y*w+x] == GRID_PEG ? '*' : ' ');
ret[y*(w+1)+w] = '\n';
}
ret[h*(w+1)] = '\0';
return ret;
}
struct game_ui {
bool dragging; /* is a drag in progress? */
int sx, sy; /* grid coords of drag start cell */
int dx, dy; /* pixel coords of current drag posn */
int cur_x, cur_y;
bool cur_visible, cur_jumping;
};
static game_ui *new_ui(const game_state *state)
{
game_ui *ui = snew(game_ui);
int x, y, v;
ui->sx = ui->sy = ui->dx = ui->dy = 0;
ui->dragging = false;
ui->cur_visible = false;
ui->cur_jumping = false;
/* make sure we start the cursor somewhere on the grid. */
for (x = 0; x < state->w; x++) {
for (y = 0; y < state->h; y++) {
v = state->grid[y*state->w+x];
if (v == GRID_PEG || v == GRID_HOLE) {
ui->cur_x = x; ui->cur_y = y;
goto found;
}
}
}
assert(!"new_ui found nowhere for cursor");
found:
return ui;
}
static void free_ui(game_ui *ui)
{
sfree(ui);
}
static char *encode_ui(const game_ui *ui)
{
return NULL;
}
static void decode_ui(game_ui *ui, const char *encoding)
{
}
static void game_changed_state(game_ui *ui, const game_state *oldstate,
const game_state *newstate)
{
/*
* Cancel a drag, in case the source square has become
* unoccupied.
*/
ui->dragging = false;
/*
* Also, cancel a keyboard-driven jump if one is half way to being
* input.
*/
ui->cur_jumping = false;
}
#define PREFERRED_TILE_SIZE 33
#define TILESIZE (ds->tilesize)
#define BORDER (TILESIZE / 2)
#define HIGHLIGHT_WIDTH (TILESIZE / 16)
#define COORD(x) ( BORDER + (x) * TILESIZE )
#define FROMCOORD(x) ( ((x) + TILESIZE - BORDER) / TILESIZE - 1 )
struct game_drawstate {
int tilesize;
blitter *drag_background;
bool dragging;
int dragx, dragy;
int w, h;
unsigned char *grid;
bool started;
int bgcolour;
};
static char *interpret_move(const game_state *state, game_ui *ui,
const game_drawstate *ds,
int x, int y, int button)
{
int w = state->w, h = state->h;
char buf[80];
if (button == LEFT_BUTTON) {
int tx, ty;
/*
* Left button down: we attempt to start a drag.
*/
/*
* There certainly shouldn't be a current drag in progress,
* unless the midend failed to send us button events in
* order; it has a responsibility to always get that right,
* so we can legitimately punish it by failing an
* assertion.
*/
assert(!ui->dragging);
tx = FROMCOORD(x);
ty = FROMCOORD(y);
if (tx >= 0 && tx < w && ty >= 0 && ty < h &&
state->grid[ty*w+tx] == GRID_PEG) {
ui->dragging = true;
ui->sx = tx;
ui->sy = ty;
ui->dx = x;
ui->dy = y;
ui->cur_visible = false;
ui->cur_jumping = false;
return UI_UPDATE;
}
} else if (button == LEFT_DRAG && ui->dragging) {
/*
* Mouse moved; just move the peg being dragged.
*/
ui->dx = x;
ui->dy = y;
return UI_UPDATE;
} else if (button == LEFT_RELEASE && ui->dragging) {
int tx, ty, dx, dy;
/*
* Button released. Identify the target square of the drag,
* see if it represents a valid move, and if so make it.
*/
ui->dragging = false; /* cancel the drag no matter what */
tx = FROMCOORD(x);
ty = FROMCOORD(y);
if (tx < 0 || tx >= w || ty < 0 || ty >= h)
return UI_UPDATE; /* target out of range */
dx = tx - ui->sx;
dy = ty - ui->sy;
if (max(abs(dx),abs(dy)) != 2 || min(abs(dx),abs(dy)) != 0)
return UI_UPDATE; /* move length was wrong */
dx /= 2;
dy /= 2;
if (state->grid[ty*w+tx] != GRID_HOLE ||
state->grid[(ty-dy)*w+(tx-dx)] != GRID_PEG ||
state->grid[ui->sy*w+ui->sx] != GRID_PEG)
return UI_UPDATE; /* grid contents were invalid */
/*
* We have a valid move. Encode it simply as source and
* destination coordinate pairs.
*/
sprintf(buf, "%d,%d-%d,%d", ui->sx, ui->sy, tx, ty);
return dupstr(buf);
} else if (IS_CURSOR_MOVE(button)) {
if (!ui->cur_jumping) {
/* Not jumping; move cursor as usual, making sure we don't
* leave the gameboard (which may be an irregular shape) */
int cx = ui->cur_x, cy = ui->cur_y;
move_cursor(button, &cx, &cy, w, h, false);
ui->cur_visible = true;
if (state->grid[cy*w+cx] == GRID_HOLE ||
state->grid[cy*w+cx] == GRID_PEG) {
ui->cur_x = cx;
ui->cur_y = cy;
}
return UI_UPDATE;
} else {
int dx, dy, mx, my, jx, jy;
/* We're jumping; if the requested direction has a hole, and
* there's a peg in the way, */
assert(state->grid[ui->cur_y*w+ui->cur_x] == GRID_PEG);
dx = (button == CURSOR_RIGHT) ? 1 : (button == CURSOR_LEFT) ? -1 : 0;
dy = (button == CURSOR_DOWN) ? 1 : (button == CURSOR_UP) ? -1 : 0;
mx = ui->cur_x+dx; my = ui->cur_y+dy;
jx = mx+dx; jy = my+dy;
ui->cur_jumping = false; /* reset, whatever. */
if (jx >= 0 && jy >= 0 && jx < w && jy < h &&
state->grid[my*w+mx] == GRID_PEG &&
state->grid[jy*w+jx] == GRID_HOLE) {
/* Move cursor to the jumped-to location (this felt more
* natural while playtesting) */
sprintf(buf, "%d,%d-%d,%d", ui->cur_x, ui->cur_y, jx, jy);
ui->cur_x = jx; ui->cur_y = jy;
return dupstr(buf);
}
return UI_UPDATE;
}
} else if (IS_CURSOR_SELECT(button)) {
if (!ui->cur_visible) {
ui->cur_visible = true;
return UI_UPDATE;
}
if (ui->cur_jumping) {
ui->cur_jumping = false;
return UI_UPDATE;
}
if (state->grid[ui->cur_y*w+ui->cur_x] == GRID_PEG) {
/* cursor is on peg: next arrow-move wil jump. */
ui->cur_jumping = true;
return UI_UPDATE;
}
return NULL;
}
return NULL;
}
static game_state *execute_move(const game_state *state, const char *move)
{
int w = state->w, h = state->h;
int sx, sy, tx, ty;
game_state *ret;
if (sscanf(move, "%d,%d-%d,%d", &sx, &sy, &tx, &ty) == 4) {
int mx, my, dx, dy;
if (sx < 0 || sx >= w || sy < 0 || sy >= h)
return NULL; /* source out of range */
if (tx < 0 || tx >= w || ty < 0 || ty >= h)
return NULL; /* target out of range */
dx = tx - sx;
dy = ty - sy;
if (max(abs(dx),abs(dy)) != 2 || min(abs(dx),abs(dy)) != 0)
return NULL; /* move length was wrong */
mx = sx + dx/2;
my = sy + dy/2;
if (state->grid[sy*w+sx] != GRID_PEG ||
state->grid[my*w+mx] != GRID_PEG ||
state->grid[ty*w+tx] != GRID_HOLE)
return NULL; /* grid contents were invalid */
ret = dup_game(state);
ret->grid[sy*w+sx] = GRID_HOLE;
ret->grid[my*w+mx] = GRID_HOLE;
ret->grid[ty*w+tx] = GRID_PEG;
/*
* Opinion varies on whether getting to a single peg counts as
* completing the game, or whether that peg has to be at a
* specific location (central in the classic cross game, for
* instance). For now we take the former, rather lax position.
*/
if (!ret->completed) {
int count = 0, i;
for (i = 0; i < w*h; i++)
if (ret->grid[i] == GRID_PEG)
count++;
if (count == 1)
ret->completed = true;
}
return ret;
}