Miscellaneous fixes from James Harvey's PalmOS porting work:
[sgt/puzzles] / cube.c
1 /*
2 * cube.c: Cube game.
3 */
4
5 #include <stdio.h>
6 #include <stdlib.h>
7 #include <string.h>
8 #include <assert.h>
9 #include <ctype.h>
10 #include <math.h>
11
12 #include "puzzles.h"
13
14 #define MAXVERTICES 20
15 #define MAXFACES 20
16 #define MAXORDER 4
17 struct solid {
18 int nvertices;
19 float vertices[MAXVERTICES * 3]; /* 3*npoints coordinates */
20 int order;
21 int nfaces;
22 int faces[MAXFACES * MAXORDER]; /* order*nfaces point indices */
23 float normals[MAXFACES * 3]; /* 3*npoints vector components */
24 float shear; /* isometric shear for nice drawing */
25 float border; /* border required around arena */
26 };
27
28 static const struct solid s_tetrahedron = {
29 4,
30 {
31 0.0F, -0.57735026919F, -0.20412414523F,
32 -0.5F, 0.28867513459F, -0.20412414523F,
33 0.0F, -0.0F, 0.6123724357F,
34 0.5F, 0.28867513459F, -0.20412414523F,
35 },
36 3, 4,
37 {
38 0,2,1, 3,1,2, 2,0,3, 1,3,0
39 },
40 {
41 -0.816496580928F, -0.471404520791F, 0.333333333334F,
42 0.0F, 0.942809041583F, 0.333333333333F,
43 0.816496580928F, -0.471404520791F, 0.333333333334F,
44 0.0F, 0.0F, -1.0F,
45 },
46 0.0F, 0.3F
47 };
48
49 static const struct solid s_cube = {
50 8,
51 {
52 -0.5F,-0.5F,-0.5F, -0.5F,-0.5F,+0.5F,
53 -0.5F,+0.5F,-0.5F, -0.5F,+0.5F,+0.5F,
54 +0.5F,-0.5F,-0.5F, +0.5F,-0.5F,+0.5F,
55 +0.5F,+0.5F,-0.5F, +0.5F,+0.5F,+0.5F,
56 },
57 4, 6,
58 {
59 0,1,3,2, 1,5,7,3, 5,4,6,7, 4,0,2,6, 0,4,5,1, 3,7,6,2
60 },
61 {
62 -1.0F,0.0F,0.0F, 0.0F,0.0F,+1.0F,
63 +1.0F,0.0F,0.0F, 0.0F,0.0F,-1.0F,
64 0.0F,-1.0F,0.0F, 0.0F,+1.0F,0.0F
65 },
66 0.3F, 0.5F
67 };
68
69 static const struct solid s_octahedron = {
70 6,
71 {
72 -0.5F, -0.28867513459472505F, 0.4082482904638664F,
73 0.5F, 0.28867513459472505F, -0.4082482904638664F,
74 -0.5F, 0.28867513459472505F, -0.4082482904638664F,
75 0.5F, -0.28867513459472505F, 0.4082482904638664F,
76 0.0F, -0.57735026918945009F, -0.4082482904638664F,
77 0.0F, 0.57735026918945009F, 0.4082482904638664F,
78 },
79 3, 8,
80 {
81 4,0,2, 0,5,2, 0,4,3, 5,0,3, 1,4,2, 5,1,2, 4,1,3, 1,5,3
82 },
83 {
84 -0.816496580928F, -0.471404520791F, -0.333333333334F,
85 -0.816496580928F, 0.471404520791F, 0.333333333334F,
86 0.0F, -0.942809041583F, 0.333333333333F,
87 0.0F, 0.0F, 1.0F,
88 0.0F, 0.0F, -1.0F,
89 0.0F, 0.942809041583F, -0.333333333333F,
90 0.816496580928F, -0.471404520791F, -0.333333333334F,
91 0.816496580928F, 0.471404520791F, 0.333333333334F,
92 },
93 0.0F, 0.5F
94 };
95
96 static const struct solid s_icosahedron = {
97 12,
98 {
99 0.0F, 0.57735026919F, 0.75576131408F,
100 0.0F, -0.93417235896F, 0.17841104489F,
101 0.0F, 0.93417235896F, -0.17841104489F,
102 0.0F, -0.57735026919F, -0.75576131408F,
103 -0.5F, -0.28867513459F, 0.75576131408F,
104 -0.5F, 0.28867513459F, -0.75576131408F,
105 0.5F, -0.28867513459F, 0.75576131408F,
106 0.5F, 0.28867513459F, -0.75576131408F,
107 -0.80901699437F, 0.46708617948F, 0.17841104489F,
108 0.80901699437F, 0.46708617948F, 0.17841104489F,
109 -0.80901699437F, -0.46708617948F, -0.17841104489F,
110 0.80901699437F, -0.46708617948F, -0.17841104489F,
111 },
112 3, 20,
113 {
114 8,0,2, 0,9,2, 1,10,3, 11,1,3, 0,4,6,
115 4,1,6, 5,2,7, 3,5,7, 4,8,10, 8,5,10,
116 9,6,11, 7,9,11, 0,8,4, 9,0,6, 10,1,4,
117 1,11,6, 8,2,5, 2,9,7, 3,10,5, 11,3,7,
118 },
119 {
120 -0.356822089773F, 0.87267799625F, 0.333333333333F,
121 0.356822089773F, 0.87267799625F, 0.333333333333F,
122 -0.356822089773F, -0.87267799625F, -0.333333333333F,
123 0.356822089773F, -0.87267799625F, -0.333333333333F,
124 -0.0F, 0.0F, 1.0F,
125 0.0F, -0.666666666667F, 0.745355992501F,
126 0.0F, 0.666666666667F, -0.745355992501F,
127 0.0F, 0.0F, -1.0F,
128 -0.934172358963F, -0.12732200375F, 0.333333333333F,
129 -0.934172358963F, 0.12732200375F, -0.333333333333F,
130 0.934172358963F, -0.12732200375F, 0.333333333333F,
131 0.934172358963F, 0.12732200375F, -0.333333333333F,
132 -0.57735026919F, 0.333333333334F, 0.745355992501F,
133 0.57735026919F, 0.333333333334F, 0.745355992501F,
134 -0.57735026919F, -0.745355992501F, 0.333333333334F,
135 0.57735026919F, -0.745355992501F, 0.333333333334F,
136 -0.57735026919F, 0.745355992501F, -0.333333333334F,
137 0.57735026919F, 0.745355992501F, -0.333333333334F,
138 -0.57735026919F, -0.333333333334F, -0.745355992501F,
139 0.57735026919F, -0.333333333334F, -0.745355992501F,
140 },
141 0.0F, 0.8F
142 };
143
144 enum {
145 TETRAHEDRON, CUBE, OCTAHEDRON, ICOSAHEDRON
146 };
147 static const struct solid *solids[] = {
148 &s_tetrahedron, &s_cube, &s_octahedron, &s_icosahedron
149 };
150
151 enum {
152 COL_BACKGROUND,
153 COL_BORDER,
154 COL_BLUE,
155 NCOLOURS
156 };
157
158 enum { LEFT, RIGHT, UP, DOWN, UP_LEFT, UP_RIGHT, DOWN_LEFT, DOWN_RIGHT };
159
160 #define GRID_SCALE 48.0F
161 #define ROLLTIME 0.13F
162
163 #define SQ(x) ( (x) * (x) )
164
165 #define MATMUL(ra,m,a) do { \
166 float rx, ry, rz, xx = (a)[0], yy = (a)[1], zz = (a)[2], *mat = (m); \
167 rx = mat[0] * xx + mat[3] * yy + mat[6] * zz; \
168 ry = mat[1] * xx + mat[4] * yy + mat[7] * zz; \
169 rz = mat[2] * xx + mat[5] * yy + mat[8] * zz; \
170 (ra)[0] = rx; (ra)[1] = ry; (ra)[2] = rz; \
171 } while (0)
172
173 #define APPROXEQ(x,y) ( SQ(x-y) < 0.1 )
174
175 struct grid_square {
176 float x, y;
177 int npoints;
178 float points[8]; /* maximum */
179 int directions[8]; /* bit masks showing point pairs */
180 int flip;
181 int blue;
182 int tetra_class;
183 };
184
185 struct game_params {
186 int solid;
187 /*
188 * Grid dimensions. For a square grid these are width and
189 * height respectively; otherwise the grid is a hexagon, with
190 * the top side and the two lower diagonals having length d1
191 * and the remaining three sides having length d2 (so that
192 * d1==d2 gives a regular hexagon, and d2==0 gives a triangle).
193 */
194 int d1, d2;
195 };
196
197 struct game_state {
198 struct game_params params;
199 const struct solid *solid;
200 int *facecolours;
201 struct grid_square *squares;
202 int nsquares;
203 int current; /* index of current grid square */
204 int sgkey[2]; /* key-point indices into grid sq */
205 int dgkey[2]; /* key-point indices into grid sq */
206 int spkey[2]; /* key-point indices into polyhedron */
207 int dpkey[2]; /* key-point indices into polyhedron */
208 int previous;
209 float angle;
210 int completed;
211 int movecount;
212 };
213
214 static game_params *default_params(void)
215 {
216 game_params *ret = snew(game_params);
217
218 ret->solid = CUBE;
219 ret->d1 = 4;
220 ret->d2 = 4;
221
222 return ret;
223 }
224
225 static int game_fetch_preset(int i, char **name, game_params **params)
226 {
227 game_params *ret = snew(game_params);
228 char *str;
229
230 switch (i) {
231 case 0:
232 str = "Cube";
233 ret->solid = CUBE;
234 ret->d1 = 4;
235 ret->d2 = 4;
236 break;
237 case 1:
238 str = "Tetrahedron";
239 ret->solid = TETRAHEDRON;
240 ret->d1 = 1;
241 ret->d2 = 2;
242 break;
243 case 2:
244 str = "Octahedron";
245 ret->solid = OCTAHEDRON;
246 ret->d1 = 2;
247 ret->d2 = 2;
248 break;
249 case 3:
250 str = "Icosahedron";
251 ret->solid = ICOSAHEDRON;
252 ret->d1 = 3;
253 ret->d2 = 3;
254 break;
255 default:
256 sfree(ret);
257 return FALSE;
258 }
259
260 *name = dupstr(str);
261 *params = ret;
262 return TRUE;
263 }
264
265 static void free_params(game_params *params)
266 {
267 sfree(params);
268 }
269
270 static game_params *dup_params(game_params *params)
271 {
272 game_params *ret = snew(game_params);
273 *ret = *params; /* structure copy */
274 return ret;
275 }
276
277 static void decode_params(game_params *ret, char const *string)
278 {
279 switch (*string) {
280 case 't': ret->solid = TETRAHEDRON; string++; break;
281 case 'c': ret->solid = CUBE; string++; break;
282 case 'o': ret->solid = OCTAHEDRON; string++; break;
283 case 'i': ret->solid = ICOSAHEDRON; string++; break;
284 default: break;
285 }
286 ret->d1 = ret->d2 = atoi(string);
287 while (*string && isdigit(*string)) string++;
288 if (*string == 'x') {
289 string++;
290 ret->d2 = atoi(string);
291 }
292 }
293
294 static char *encode_params(game_params *params, int full)
295 {
296 char data[256];
297
298 assert(params->solid >= 0 && params->solid < 4);
299 sprintf(data, "%c%dx%d", "tcoi"[params->solid], params->d1, params->d2);
300
301 return dupstr(data);
302 }
303 typedef void (*egc_callback)(void *, struct grid_square *);
304
305 static void enum_grid_squares(game_params *params, egc_callback callback, void *ctx)
306 {
307 const struct solid *solid = solids[params->solid];
308
309 if (solid->order == 4) {
310 int x, y;
311
312 for (y = 0; y < params->d2; y++)
313 for (x = 0; x < params->d1; x++) {
314 struct grid_square sq;
315
316 sq.x = (float)x;
317 sq.y = (float)y;
318 sq.points[0] = x - 0.5F;
319 sq.points[1] = y - 0.5F;
320 sq.points[2] = x - 0.5F;
321 sq.points[3] = y + 0.5F;
322 sq.points[4] = x + 0.5F;
323 sq.points[5] = y + 0.5F;
324 sq.points[6] = x + 0.5F;
325 sq.points[7] = y - 0.5F;
326 sq.npoints = 4;
327
328 sq.directions[LEFT] = 0x03; /* 0,1 */
329 sq.directions[RIGHT] = 0x0C; /* 2,3 */
330 sq.directions[UP] = 0x09; /* 0,3 */
331 sq.directions[DOWN] = 0x06; /* 1,2 */
332 sq.directions[UP_LEFT] = 0; /* no diagonals in a square */
333 sq.directions[UP_RIGHT] = 0; /* no diagonals in a square */
334 sq.directions[DOWN_LEFT] = 0; /* no diagonals in a square */
335 sq.directions[DOWN_RIGHT] = 0; /* no diagonals in a square */
336
337 sq.flip = FALSE;
338
339 /*
340 * This is supremely irrelevant, but just to avoid
341 * having any uninitialised structure members...
342 */
343 sq.tetra_class = 0;
344
345 callback(ctx, &sq);
346 }
347 } else {
348 int row, rowlen, other, i, firstix = -1;
349 float theight = (float)(sqrt(3) / 2.0);
350
351 for (row = 0; row < params->d1 + params->d2; row++) {
352 if (row < params->d2) {
353 other = +1;
354 rowlen = row + params->d1;
355 } else {
356 other = -1;
357 rowlen = 2*params->d2 + params->d1 - row;
358 }
359
360 /*
361 * There are `rowlen' down-pointing triangles.
362 */
363 for (i = 0; i < rowlen; i++) {
364 struct grid_square sq;
365 int ix;
366 float x, y;
367
368 ix = (2 * i - (rowlen-1));
369 x = ix * 0.5F;
370 y = theight * row;
371 sq.x = x;
372 sq.y = y + theight / 3;
373 sq.points[0] = x - 0.5F;
374 sq.points[1] = y;
375 sq.points[2] = x;
376 sq.points[3] = y + theight;
377 sq.points[4] = x + 0.5F;
378 sq.points[5] = y;
379 sq.npoints = 3;
380
381 sq.directions[LEFT] = 0x03; /* 0,1 */
382 sq.directions[RIGHT] = 0x06; /* 1,2 */
383 sq.directions[UP] = 0x05; /* 0,2 */
384 sq.directions[DOWN] = 0; /* invalid move */
385
386 /*
387 * Down-pointing triangle: both the up diagonals go
388 * up, and the down ones go left and right.
389 */
390 sq.directions[UP_LEFT] = sq.directions[UP_RIGHT] =
391 sq.directions[UP];
392 sq.directions[DOWN_LEFT] = sq.directions[LEFT];
393 sq.directions[DOWN_RIGHT] = sq.directions[RIGHT];
394
395 sq.flip = TRUE;
396
397 if (firstix < 0)
398 firstix = ix & 3;
399 ix -= firstix;
400 sq.tetra_class = ((row+(ix&1)) & 2) ^ (ix & 3);
401
402 callback(ctx, &sq);
403 }
404
405 /*
406 * There are `rowlen+other' up-pointing triangles.
407 */
408 for (i = 0; i < rowlen+other; i++) {
409 struct grid_square sq;
410 int ix;
411 float x, y;
412
413 ix = (2 * i - (rowlen+other-1));
414 x = ix * 0.5F;
415 y = theight * row;
416 sq.x = x;
417 sq.y = y + 2*theight / 3;
418 sq.points[0] = x + 0.5F;
419 sq.points[1] = y + theight;
420 sq.points[2] = x;
421 sq.points[3] = y;
422 sq.points[4] = x - 0.5F;
423 sq.points[5] = y + theight;
424 sq.npoints = 3;
425
426 sq.directions[LEFT] = 0x06; /* 1,2 */
427 sq.directions[RIGHT] = 0x03; /* 0,1 */
428 sq.directions[DOWN] = 0x05; /* 0,2 */
429 sq.directions[UP] = 0; /* invalid move */
430
431 /*
432 * Up-pointing triangle: both the down diagonals go
433 * down, and the up ones go left and right.
434 */
435 sq.directions[DOWN_LEFT] = sq.directions[DOWN_RIGHT] =
436 sq.directions[DOWN];
437 sq.directions[UP_LEFT] = sq.directions[LEFT];
438 sq.directions[UP_RIGHT] = sq.directions[RIGHT];
439
440 sq.flip = FALSE;
441
442 if (firstix < 0)
443 firstix = (ix - 1) & 3;
444 ix -= firstix;
445 sq.tetra_class = ((row+(ix&1)) & 2) ^ (ix & 3);
446
447 callback(ctx, &sq);
448 }
449 }
450 }
451 }
452
453 static int grid_area(int d1, int d2, int order)
454 {
455 /*
456 * An NxM grid of squares has NM squares in it.
457 *
458 * A grid of triangles with dimensions A and B has a total of
459 * A^2 + B^2 + 4AB triangles in it. (You can divide it up into
460 * a side-A triangle containing A^2 subtriangles, a side-B
461 * triangle containing B^2, and two congruent parallelograms,
462 * each with side lengths A and B, each therefore containing AB
463 * two-triangle rhombuses.)
464 */
465 if (order == 4)
466 return d1 * d2;
467 else
468 return d1*d1 + d2*d2 + 4*d1*d2;
469 }
470
471 static config_item *game_configure(game_params *params)
472 {
473 config_item *ret = snewn(4, config_item);
474 char buf[80];
475
476 ret[0].name = "Type of solid";
477 ret[0].type = C_CHOICES;
478 ret[0].sval = ":Tetrahedron:Cube:Octahedron:Icosahedron";
479 ret[0].ival = params->solid;
480
481 ret[1].name = "Width / top";
482 ret[1].type = C_STRING;
483 sprintf(buf, "%d", params->d1);
484 ret[1].sval = dupstr(buf);
485 ret[1].ival = 0;
486
487 ret[2].name = "Height / bottom";
488 ret[2].type = C_STRING;
489 sprintf(buf, "%d", params->d2);
490 ret[2].sval = dupstr(buf);
491 ret[2].ival = 0;
492
493 ret[3].name = NULL;
494 ret[3].type = C_END;
495 ret[3].sval = NULL;
496 ret[3].ival = 0;
497
498 return ret;
499 }
500
501 static game_params *custom_params(config_item *cfg)
502 {
503 game_params *ret = snew(game_params);
504
505 ret->solid = cfg[0].ival;
506 ret->d1 = atoi(cfg[1].sval);
507 ret->d2 = atoi(cfg[2].sval);
508
509 return ret;
510 }
511
512 static void count_grid_square_callback(void *ctx, struct grid_square *sq)
513 {
514 int *classes = (int *)ctx;
515 int thisclass;
516
517 if (classes[4] == 4)
518 thisclass = sq->tetra_class;
519 else if (classes[4] == 2)
520 thisclass = sq->flip;
521 else
522 thisclass = 0;
523
524 classes[thisclass]++;
525 }
526
527 static char *validate_params(game_params *params)
528 {
529 int classes[5];
530 int i;
531
532 if (params->solid < 0 || params->solid >= lenof(solids))
533 return "Unrecognised solid type";
534
535 if (solids[params->solid]->order == 4) {
536 if (params->d1 <= 0 || params->d2 <= 0)
537 return "Both grid dimensions must be greater than zero";
538 } else {
539 if (params->d1 <= 0 && params->d2 <= 0)
540 return "At least one grid dimension must be greater than zero";
541 }
542
543 for (i = 0; i < 4; i++)
544 classes[i] = 0;
545 if (params->solid == TETRAHEDRON)
546 classes[4] = 4;
547 else if (params->solid == OCTAHEDRON)
548 classes[4] = 2;
549 else
550 classes[4] = 1;
551 enum_grid_squares(params, count_grid_square_callback, classes);
552
553 for (i = 0; i < classes[4]; i++)
554 if (classes[i] < solids[params->solid]->nfaces / classes[4])
555 return "Not enough grid space to place all blue faces";
556
557 if (grid_area(params->d1, params->d2, solids[params->solid]->order) <
558 solids[params->solid]->nfaces + 1)
559 return "Not enough space to place the solid on an empty square";
560
561 return NULL;
562 }
563
564 struct grid_data {
565 int *gridptrs[4];
566 int nsquares[4];
567 int nclasses;
568 int squareindex;
569 };
570
571 static void classify_grid_square_callback(void *ctx, struct grid_square *sq)
572 {
573 struct grid_data *data = (struct grid_data *)ctx;
574 int thisclass;
575
576 if (data->nclasses == 4)
577 thisclass = sq->tetra_class;
578 else if (data->nclasses == 2)
579 thisclass = sq->flip;
580 else
581 thisclass = 0;
582
583 data->gridptrs[thisclass][data->nsquares[thisclass]++] =
584 data->squareindex++;
585 }
586
587 static char *new_game_desc(game_params *params, random_state *rs,
588 game_aux_info **aux, int interactive)
589 {
590 struct grid_data data;
591 int i, j, k, m, area, facesperclass;
592 int *flags;
593 char *desc, *p;
594
595 /*
596 * Enumerate the grid squares, dividing them into equivalence
597 * classes as appropriate. (For the tetrahedron, there is one
598 * equivalence class for each face; for the octahedron there
599 * are two classes; for the other two solids there's only one.)
600 */
601
602 area = grid_area(params->d1, params->d2, solids[params->solid]->order);
603 if (params->solid == TETRAHEDRON)
604 data.nclasses = 4;
605 else if (params->solid == OCTAHEDRON)
606 data.nclasses = 2;
607 else
608 data.nclasses = 1;
609 data.gridptrs[0] = snewn(data.nclasses * area, int);
610 for (i = 0; i < data.nclasses; i++) {
611 data.gridptrs[i] = data.gridptrs[0] + i * area;
612 data.nsquares[i] = 0;
613 }
614 data.squareindex = 0;
615 enum_grid_squares(params, classify_grid_square_callback, &data);
616
617 facesperclass = solids[params->solid]->nfaces / data.nclasses;
618
619 for (i = 0; i < data.nclasses; i++)
620 assert(data.nsquares[i] >= facesperclass);
621 assert(data.squareindex == area);
622
623 /*
624 * So now we know how many faces to allocate in each class. Get
625 * on with it.
626 */
627 flags = snewn(area, int);
628 for (i = 0; i < area; i++)
629 flags[i] = FALSE;
630
631 for (i = 0; i < data.nclasses; i++) {
632 for (j = 0; j < facesperclass; j++) {
633 int n = random_upto(rs, data.nsquares[i]);
634
635 assert(!flags[data.gridptrs[i][n]]);
636 flags[data.gridptrs[i][n]] = TRUE;
637
638 /*
639 * Move everything else up the array. I ought to use a
640 * better data structure for this, but for such small
641 * numbers it hardly seems worth the effort.
642 */
643 while (n < data.nsquares[i]-1) {
644 data.gridptrs[i][n] = data.gridptrs[i][n+1];
645 n++;
646 }
647 data.nsquares[i]--;
648 }
649 }
650
651 /*
652 * Now we know precisely which squares are blue. Encode this
653 * information in hex. While we're looping over this, collect
654 * the non-blue squares into a list in the now-unused gridptrs
655 * array.
656 */
657 desc = snewn(area / 4 + 40, char);
658 p = desc;
659 j = 0;
660 k = 8;
661 m = 0;
662 for (i = 0; i < area; i++) {
663 if (flags[i]) {
664 j |= k;
665 } else {
666 data.gridptrs[0][m++] = i;
667 }
668 k >>= 1;
669 if (!k) {
670 *p++ = "0123456789ABCDEF"[j];
671 k = 8;
672 j = 0;
673 }
674 }
675 if (k != 8)
676 *p++ = "0123456789ABCDEF"[j];
677
678 /*
679 * Choose a non-blue square for the polyhedron.
680 */
681 sprintf(p, ",%d", data.gridptrs[0][random_upto(rs, m)]);
682
683 sfree(data.gridptrs[0]);
684 sfree(flags);
685
686 return desc;
687 }
688
689 static void game_free_aux_info(game_aux_info *aux)
690 {
691 assert(!"Shouldn't happen");
692 }
693
694 static void add_grid_square_callback(void *ctx, struct grid_square *sq)
695 {
696 game_state *state = (game_state *)ctx;
697
698 state->squares[state->nsquares] = *sq; /* structure copy */
699 state->squares[state->nsquares].blue = FALSE;
700 state->nsquares++;
701 }
702
703 static int lowest_face(const struct solid *solid)
704 {
705 int i, j, best;
706 float zmin;
707
708 best = 0;
709 zmin = 0.0;
710 for (i = 0; i < solid->nfaces; i++) {
711 float z = 0;
712
713 for (j = 0; j < solid->order; j++) {
714 int f = solid->faces[i*solid->order + j];
715 z += solid->vertices[f*3+2];
716 }
717
718 if (i == 0 || zmin > z) {
719 zmin = z;
720 best = i;
721 }
722 }
723
724 return best;
725 }
726
727 static int align_poly(const struct solid *solid, struct grid_square *sq,
728 int *pkey)
729 {
730 float zmin;
731 int i, j;
732 int flip = (sq->flip ? -1 : +1);
733
734 /*
735 * First, find the lowest z-coordinate present in the solid.
736 */
737 zmin = 0.0;
738 for (i = 0; i < solid->nvertices; i++)
739 if (zmin > solid->vertices[i*3+2])
740 zmin = solid->vertices[i*3+2];
741
742 /*
743 * Now go round the grid square. For each point in the grid
744 * square, we're looking for a point of the polyhedron with the
745 * same x- and y-coordinates (relative to the square's centre),
746 * and z-coordinate equal to zmin (near enough).
747 */
748 for (j = 0; j < sq->npoints; j++) {
749 int matches, index;
750
751 matches = 0;
752 index = -1;
753
754 for (i = 0; i < solid->nvertices; i++) {
755 float dist = 0;
756
757 dist += SQ(solid->vertices[i*3+0] * flip - sq->points[j*2+0] + sq->x);
758 dist += SQ(solid->vertices[i*3+1] * flip - sq->points[j*2+1] + sq->y);
759 dist += SQ(solid->vertices[i*3+2] - zmin);
760
761 if (dist < 0.1) {
762 matches++;
763 index = i;
764 }
765 }
766
767 if (matches != 1 || index < 0)
768 return FALSE;
769 pkey[j] = index;
770 }
771
772 return TRUE;
773 }
774
775 static void flip_poly(struct solid *solid, int flip)
776 {
777 int i;
778
779 if (flip) {
780 for (i = 0; i < solid->nvertices; i++) {
781 solid->vertices[i*3+0] *= -1;
782 solid->vertices[i*3+1] *= -1;
783 }
784 for (i = 0; i < solid->nfaces; i++) {
785 solid->normals[i*3+0] *= -1;
786 solid->normals[i*3+1] *= -1;
787 }
788 }
789 }
790
791 static struct solid *transform_poly(const struct solid *solid, int flip,
792 int key0, int key1, float angle)
793 {
794 struct solid *ret = snew(struct solid);
795 float vx, vy, ax, ay;
796 float vmatrix[9], amatrix[9], vmatrix2[9];
797 int i;
798
799 *ret = *solid; /* structure copy */
800
801 flip_poly(ret, flip);
802
803 /*
804 * Now rotate the polyhedron through the given angle. We must
805 * rotate about the Z-axis to bring the two vertices key0 and
806 * key1 into horizontal alignment, then rotate about the
807 * X-axis, then rotate back again.
808 */
809 vx = ret->vertices[key1*3+0] - ret->vertices[key0*3+0];
810 vy = ret->vertices[key1*3+1] - ret->vertices[key0*3+1];
811 assert(APPROXEQ(vx*vx + vy*vy, 1.0));
812
813 vmatrix[0] = vx; vmatrix[3] = vy; vmatrix[6] = 0;
814 vmatrix[1] = -vy; vmatrix[4] = vx; vmatrix[7] = 0;
815 vmatrix[2] = 0; vmatrix[5] = 0; vmatrix[8] = 1;
816
817 ax = (float)cos(angle);
818 ay = (float)sin(angle);
819
820 amatrix[0] = 1; amatrix[3] = 0; amatrix[6] = 0;
821 amatrix[1] = 0; amatrix[4] = ax; amatrix[7] = ay;
822 amatrix[2] = 0; amatrix[5] = -ay; amatrix[8] = ax;
823
824 memcpy(vmatrix2, vmatrix, sizeof(vmatrix));
825 vmatrix2[1] = vy;
826 vmatrix2[3] = -vy;
827
828 for (i = 0; i < ret->nvertices; i++) {
829 MATMUL(ret->vertices + 3*i, vmatrix, ret->vertices + 3*i);
830 MATMUL(ret->vertices + 3*i, amatrix, ret->vertices + 3*i);
831 MATMUL(ret->vertices + 3*i, vmatrix2, ret->vertices + 3*i);
832 }
833 for (i = 0; i < ret->nfaces; i++) {
834 MATMUL(ret->normals + 3*i, vmatrix, ret->normals + 3*i);
835 MATMUL(ret->normals + 3*i, amatrix, ret->normals + 3*i);
836 MATMUL(ret->normals + 3*i, vmatrix2, ret->normals + 3*i);
837 }
838
839 return ret;
840 }
841
842 static char *validate_desc(game_params *params, char *desc)
843 {
844 int area = grid_area(params->d1, params->d2, solids[params->solid]->order);
845 int i, j;
846
847 i = (area + 3) / 4;
848 for (j = 0; j < i; j++) {
849 int c = desc[j];
850 if (c >= '0' && c <= '9') continue;
851 if (c >= 'A' && c <= 'F') continue;
852 if (c >= 'a' && c <= 'f') continue;
853 return "Not enough hex digits at start of string";
854 /* NB if desc[j]=='\0' that will also be caught here, so we're safe */
855 }
856
857 if (desc[i] != ',')
858 return "Expected ',' after hex digits";
859
860 i++;
861 do {
862 if (desc[i] < '0' || desc[i] > '9')
863 return "Expected decimal integer after ','";
864 i++;
865 } while (desc[i]);
866
867 return NULL;
868 }
869
870 static game_state *new_game(midend_data *me, game_params *params, char *desc)
871 {
872 game_state *state = snew(game_state);
873 int area;
874
875 state->params = *params; /* structure copy */
876 state->solid = solids[params->solid];
877
878 area = grid_area(params->d1, params->d2, state->solid->order);
879 state->squares = snewn(area, struct grid_square);
880 state->nsquares = 0;
881 enum_grid_squares(params, add_grid_square_callback, state);
882 assert(state->nsquares == area);
883
884 state->facecolours = snewn(state->solid->nfaces, int);
885 memset(state->facecolours, 0, state->solid->nfaces * sizeof(int));
886
887 /*
888 * Set up the blue squares and polyhedron position according to
889 * the game description.
890 */
891 {
892 char *p = desc;
893 int i, j, v;
894
895 j = 8;
896 v = 0;
897 for (i = 0; i < state->nsquares; i++) {
898 if (j == 8) {
899 v = *p++;
900 if (v >= '0' && v <= '9')
901 v -= '0';
902 else if (v >= 'A' && v <= 'F')
903 v -= 'A' - 10;
904 else if (v >= 'a' && v <= 'f')
905 v -= 'a' - 10;
906 else
907 break;
908 }
909 if (v & j)
910 state->squares[i].blue = TRUE;
911 j >>= 1;
912 if (j == 0)
913 j = 8;
914 }
915
916 if (*p == ',')
917 p++;
918
919 state->current = atoi(p);
920 if (state->current < 0 || state->current >= state->nsquares)
921 state->current = 0; /* got to do _something_ */
922 }
923
924 /*
925 * Align the polyhedron with its grid square and determine
926 * initial key points.
927 */
928 {
929 int pkey[4];
930 int ret;
931
932 ret = align_poly(state->solid, &state->squares[state->current], pkey);
933 assert(ret);
934
935 state->dpkey[0] = state->spkey[0] = pkey[0];
936 state->dpkey[1] = state->spkey[0] = pkey[1];
937 state->dgkey[0] = state->sgkey[0] = 0;
938 state->dgkey[1] = state->sgkey[0] = 1;
939 }
940
941 state->previous = state->current;
942 state->angle = 0.0;
943 state->completed = 0;
944 state->movecount = 0;
945
946 return state;
947 }
948
949 static game_state *dup_game(game_state *state)
950 {
951 game_state *ret = snew(game_state);
952
953 ret->params = state->params; /* structure copy */
954 ret->solid = state->solid;
955 ret->facecolours = snewn(ret->solid->nfaces, int);
956 memcpy(ret->facecolours, state->facecolours,
957 ret->solid->nfaces * sizeof(int));
958 ret->nsquares = state->nsquares;
959 ret->current = state->current;
960 ret->squares = snewn(ret->nsquares, struct grid_square);
961 memcpy(ret->squares, state->squares,
962 ret->nsquares * sizeof(struct grid_square));
963 ret->dpkey[0] = state->dpkey[0];
964 ret->dpkey[1] = state->dpkey[1];
965 ret->dgkey[0] = state->dgkey[0];
966 ret->dgkey[1] = state->dgkey[1];
967 ret->spkey[0] = state->spkey[0];
968 ret->spkey[1] = state->spkey[1];
969 ret->sgkey[0] = state->sgkey[0];
970 ret->sgkey[1] = state->sgkey[1];
971 ret->previous = state->previous;
972 ret->angle = state->angle;
973 ret->completed = state->completed;
974 ret->movecount = state->movecount;
975
976 return ret;
977 }
978
979 static void free_game(game_state *state)
980 {
981 sfree(state->squares);
982 sfree(state->facecolours);
983 sfree(state);
984 }
985
986 static game_state *solve_game(game_state *state, game_aux_info *aux,
987 char **error)
988 {
989 return NULL;
990 }
991
992 static char *game_text_format(game_state *state)
993 {
994 return NULL;
995 }
996
997 static game_ui *new_ui(game_state *state)
998 {
999 return NULL;
1000 }
1001
1002 static void free_ui(game_ui *ui)
1003 {
1004 }
1005
1006 struct game_drawstate {
1007 int ox, oy; /* pixel position of float origin */
1008 };
1009
1010 static game_state *make_move(game_state *from, game_ui *ui, game_drawstate *ds,
1011 int x, int y, int button)
1012 {
1013 int direction;
1014 int pkey[2], skey[2], dkey[2];
1015 float points[4];
1016 game_state *ret;
1017 float angle;
1018 int i, j, dest, mask;
1019 struct solid *poly;
1020
1021 button = button & (~MOD_MASK | MOD_NUM_KEYPAD);
1022
1023 /*
1024 * Moves can be made with the cursor keys or numeric keypad, or
1025 * alternatively you can left-click and the polyhedron will
1026 * move in the general direction of the mouse pointer.
1027 */
1028 if (button == CURSOR_UP || button == (MOD_NUM_KEYPAD | '8'))
1029 direction = UP;
1030 else if (button == CURSOR_DOWN || button == (MOD_NUM_KEYPAD | '2'))
1031 direction = DOWN;
1032 else if (button == CURSOR_LEFT || button == (MOD_NUM_KEYPAD | '4'))
1033 direction = LEFT;
1034 else if (button == CURSOR_RIGHT || button == (MOD_NUM_KEYPAD | '6'))
1035 direction = RIGHT;
1036 else if (button == (MOD_NUM_KEYPAD | '7'))
1037 direction = UP_LEFT;
1038 else if (button == (MOD_NUM_KEYPAD | '1'))
1039 direction = DOWN_LEFT;
1040 else if (button == (MOD_NUM_KEYPAD | '9'))
1041 direction = UP_RIGHT;
1042 else if (button == (MOD_NUM_KEYPAD | '3'))
1043 direction = DOWN_RIGHT;
1044 else if (button == LEFT_BUTTON) {
1045 /*
1046 * Find the bearing of the click point from the current
1047 * square's centre.
1048 */
1049 int cx, cy;
1050 double angle;
1051
1052 cx = from->squares[from->current].x * GRID_SCALE + ds->ox;
1053 cy = from->squares[from->current].y * GRID_SCALE + ds->oy;
1054
1055 if (x == cx && y == cy)
1056 return NULL; /* clicked in exact centre! */
1057 angle = atan2(y - cy, x - cx);
1058
1059 /*
1060 * There are three possibilities.
1061 *
1062 * - This square is a square, so we choose between UP,
1063 * DOWN, LEFT and RIGHT by dividing the available angle
1064 * at the 45-degree points.
1065 *
1066 * - This square is an up-pointing triangle, so we choose
1067 * between DOWN, LEFT and RIGHT by dividing into
1068 * 120-degree arcs.
1069 *
1070 * - This square is a down-pointing triangle, so we choose
1071 * between UP, LEFT and RIGHT in the inverse manner.
1072 *
1073 * Don't forget that since our y-coordinates increase
1074 * downwards, `angle' is measured _clockwise_ from the
1075 * x-axis, not anticlockwise as most mathematicians would
1076 * instinctively assume.
1077 */
1078 if (from->squares[from->current].npoints == 4) {
1079 /* Square. */
1080 if (fabs(angle) > 3*PI/4)
1081 direction = LEFT;
1082 else if (fabs(angle) < PI/4)
1083 direction = RIGHT;
1084 else if (angle > 0)
1085 direction = DOWN;
1086 else
1087 direction = UP;
1088 } else if (from->squares[from->current].directions[UP] == 0) {
1089 /* Up-pointing triangle. */
1090 if (angle < -PI/2 || angle > 5*PI/6)
1091 direction = LEFT;
1092 else if (angle > PI/6)
1093 direction = DOWN;
1094 else
1095 direction = RIGHT;
1096 } else {
1097 /* Down-pointing triangle. */
1098 assert(from->squares[from->current].directions[DOWN] == 0);
1099 if (angle > PI/2 || angle < -5*PI/6)
1100 direction = LEFT;
1101 else if (angle < -PI/6)
1102 direction = UP;
1103 else
1104 direction = RIGHT;
1105 }
1106 } else
1107 return NULL;
1108
1109 /*
1110 * Find the two points in the current grid square which
1111 * correspond to this move.
1112 */
1113 mask = from->squares[from->current].directions[direction];
1114 if (mask == 0)
1115 return NULL;
1116 for (i = j = 0; i < from->squares[from->current].npoints; i++)
1117 if (mask & (1 << i)) {
1118 points[j*2] = from->squares[from->current].points[i*2];
1119 points[j*2+1] = from->squares[from->current].points[i*2+1];
1120 skey[j] = i;
1121 j++;
1122 }
1123 assert(j == 2);
1124
1125 /*
1126 * Now find the other grid square which shares those points.
1127 * This is our move destination.
1128 */
1129 dest = -1;
1130 for (i = 0; i < from->nsquares; i++)
1131 if (i != from->current) {
1132 int match = 0;
1133 float dist;
1134
1135 for (j = 0; j < from->squares[i].npoints; j++) {
1136 dist = (SQ(from->squares[i].points[j*2] - points[0]) +
1137 SQ(from->squares[i].points[j*2+1] - points[1]));
1138 if (dist < 0.1)
1139 dkey[match++] = j;
1140 dist = (SQ(from->squares[i].points[j*2] - points[2]) +
1141 SQ(from->squares[i].points[j*2+1] - points[3]));
1142 if (dist < 0.1)
1143 dkey[match++] = j;
1144 }
1145
1146 if (match == 2) {
1147 dest = i;
1148 break;
1149 }
1150 }
1151
1152 if (dest < 0)
1153 return NULL;
1154
1155 ret = dup_game(from);
1156 ret->current = i;
1157
1158 /*
1159 * So we know what grid square we're aiming for, and we also
1160 * know the two key points (as indices in both the source and
1161 * destination grid squares) which are invariant between source
1162 * and destination.
1163 *
1164 * Next we must roll the polyhedron on to that square. So we
1165 * find the indices of the key points within the polyhedron's
1166 * vertex array, then use those in a call to transform_poly,
1167 * and align the result on the new grid square.
1168 */
1169 {
1170 int all_pkey[4];
1171 align_poly(from->solid, &from->squares[from->current], all_pkey);
1172 pkey[0] = all_pkey[skey[0]];
1173 pkey[1] = all_pkey[skey[1]];
1174 /*
1175 * Now pkey[0] corresponds to skey[0] and dkey[0], and
1176 * likewise [1].
1177 */
1178 }
1179
1180 /*
1181 * Now find the angle through which to rotate the polyhedron.
1182 * Do this by finding the two faces that share the two vertices
1183 * we've found, and taking the dot product of their normals.
1184 */
1185 {
1186 int f[2], nf = 0;
1187 float dp;
1188
1189 for (i = 0; i < from->solid->nfaces; i++) {
1190 int match = 0;
1191 for (j = 0; j < from->solid->order; j++)
1192 if (from->solid->faces[i*from->solid->order + j] == pkey[0] ||
1193 from->solid->faces[i*from->solid->order + j] == pkey[1])
1194 match++;
1195 if (match == 2) {
1196 assert(nf < 2);
1197 f[nf++] = i;
1198 }
1199 }
1200
1201 assert(nf == 2);
1202
1203 dp = 0;
1204 for (i = 0; i < 3; i++)
1205 dp += (from->solid->normals[f[0]*3+i] *
1206 from->solid->normals[f[1]*3+i]);
1207 angle = (float)acos(dp);
1208 }
1209
1210 /*
1211 * Now transform the polyhedron. We aren't entirely sure
1212 * whether we need to rotate through angle or -angle, and the
1213 * simplest way round this is to try both and see which one
1214 * aligns successfully!
1215 *
1216 * Unfortunately, _both_ will align successfully if this is a
1217 * cube, which won't tell us anything much. So for that
1218 * particular case, I resort to gross hackery: I simply negate
1219 * the angle before trying the alignment, depending on the
1220 * direction. Which directions work which way is determined by
1221 * pure trial and error. I said it was gross :-/
1222 */
1223 {
1224 int all_pkey[4];
1225 int success;
1226
1227 if (from->solid->order == 4 && direction == UP)
1228 angle = -angle; /* HACK */
1229
1230 poly = transform_poly(from->solid,
1231 from->squares[from->current].flip,
1232 pkey[0], pkey[1], angle);
1233 flip_poly(poly, from->squares[ret->current].flip);
1234 success = align_poly(poly, &from->squares[ret->current], all_pkey);
1235
1236 if (!success) {
1237 sfree(poly);
1238 angle = -angle;
1239 poly = transform_poly(from->solid,
1240 from->squares[from->current].flip,
1241 pkey[0], pkey[1], angle);
1242 flip_poly(poly, from->squares[ret->current].flip);
1243 success = align_poly(poly, &from->squares[ret->current], all_pkey);
1244 }
1245
1246 assert(success);
1247 }
1248
1249 /*
1250 * Now we have our rotated polyhedron, which we expect to be
1251 * exactly congruent to the one we started with - but with the
1252 * faces permuted. So we map that congruence and thereby figure
1253 * out how to permute the faces as a result of the polyhedron
1254 * having rolled.
1255 */
1256 {
1257 int *newcolours = snewn(from->solid->nfaces, int);
1258
1259 for (i = 0; i < from->solid->nfaces; i++)
1260 newcolours[i] = -1;
1261
1262 for (i = 0; i < from->solid->nfaces; i++) {
1263 int nmatch = 0;
1264
1265 /*
1266 * Now go through the transformed polyhedron's faces
1267 * and figure out which one's normal is approximately
1268 * equal to this one.
1269 */
1270 for (j = 0; j < poly->nfaces; j++) {
1271 float dist;
1272 int k;
1273
1274 dist = 0;
1275
1276 for (k = 0; k < 3; k++)
1277 dist += SQ(poly->normals[j*3+k] -
1278 from->solid->normals[i*3+k]);
1279
1280 if (APPROXEQ(dist, 0)) {
1281 nmatch++;
1282 newcolours[i] = ret->facecolours[j];
1283 }
1284 }
1285
1286 assert(nmatch == 1);
1287 }
1288
1289 for (i = 0; i < from->solid->nfaces; i++)
1290 assert(newcolours[i] != -1);
1291
1292 sfree(ret->facecolours);
1293 ret->facecolours = newcolours;
1294 }
1295
1296 ret->movecount++;
1297
1298 /*
1299 * And finally, swap the colour between the bottom face of the
1300 * polyhedron and the face we've just landed on.
1301 *
1302 * We don't do this if the game is already complete, since we
1303 * allow the user to roll the fully blue polyhedron around the
1304 * grid as a feeble reward.
1305 */
1306 if (!ret->completed) {
1307 i = lowest_face(from->solid);
1308 j = ret->facecolours[i];
1309 ret->facecolours[i] = ret->squares[ret->current].blue;
1310 ret->squares[ret->current].blue = j;
1311
1312 /*
1313 * Detect game completion.
1314 */
1315 j = 0;
1316 for (i = 0; i < ret->solid->nfaces; i++)
1317 if (ret->facecolours[i])
1318 j++;
1319 if (j == ret->solid->nfaces)
1320 ret->completed = ret->movecount;
1321 }
1322
1323 sfree(poly);
1324
1325 /*
1326 * Align the normal polyhedron with its grid square, to get key
1327 * points for non-animated display.
1328 */
1329 {
1330 int pkey[4];
1331 int success;
1332
1333 success = align_poly(ret->solid, &ret->squares[ret->current], pkey);
1334 assert(success);
1335
1336 ret->dpkey[0] = pkey[0];
1337 ret->dpkey[1] = pkey[1];
1338 ret->dgkey[0] = 0;
1339 ret->dgkey[1] = 1;
1340 }
1341
1342
1343 ret->spkey[0] = pkey[0];
1344 ret->spkey[1] = pkey[1];
1345 ret->sgkey[0] = skey[0];
1346 ret->sgkey[1] = skey[1];
1347 ret->previous = from->current;
1348 ret->angle = angle;
1349
1350 return ret;
1351 }
1352
1353 /* ----------------------------------------------------------------------
1354 * Drawing routines.
1355 */
1356
1357 struct bbox {
1358 float l, r, u, d;
1359 };
1360
1361 static void find_bbox_callback(void *ctx, struct grid_square *sq)
1362 {
1363 struct bbox *bb = (struct bbox *)ctx;
1364 int i;
1365
1366 for (i = 0; i < sq->npoints; i++) {
1367 if (bb->l > sq->points[i*2]) bb->l = sq->points[i*2];
1368 if (bb->r < sq->points[i*2]) bb->r = sq->points[i*2];
1369 if (bb->u > sq->points[i*2+1]) bb->u = sq->points[i*2+1];
1370 if (bb->d < sq->points[i*2+1]) bb->d = sq->points[i*2+1];
1371 }
1372 }
1373
1374 static struct bbox find_bbox(game_params *params)
1375 {
1376 struct bbox bb;
1377
1378 /*
1379 * These should be hugely more than the real bounding box will
1380 * be.
1381 */
1382 bb.l = 2.0F * (params->d1 + params->d2);
1383 bb.r = -2.0F * (params->d1 + params->d2);
1384 bb.u = 2.0F * (params->d1 + params->d2);
1385 bb.d = -2.0F * (params->d1 + params->d2);
1386 enum_grid_squares(params, find_bbox_callback, &bb);
1387
1388 return bb;
1389 }
1390
1391 static void game_size(game_params *params, int *x, int *y)
1392 {
1393 struct bbox bb = find_bbox(params);
1394 *x = (int)((bb.r - bb.l + 2*solids[params->solid]->border) * GRID_SCALE);
1395 *y = (int)((bb.d - bb.u + 2*solids[params->solid]->border) * GRID_SCALE);
1396 }
1397
1398 static float *game_colours(frontend *fe, game_state *state, int *ncolours)
1399 {
1400 float *ret = snewn(3 * NCOLOURS, float);
1401
1402 frontend_default_colour(fe, &ret[COL_BACKGROUND * 3]);
1403
1404 ret[COL_BORDER * 3 + 0] = 0.0;
1405 ret[COL_BORDER * 3 + 1] = 0.0;
1406 ret[COL_BORDER * 3 + 2] = 0.0;
1407
1408 ret[COL_BLUE * 3 + 0] = 0.0;
1409 ret[COL_BLUE * 3 + 1] = 0.0;
1410 ret[COL_BLUE * 3 + 2] = 1.0;
1411
1412 *ncolours = NCOLOURS;
1413 return ret;
1414 }
1415
1416 static game_drawstate *game_new_drawstate(game_state *state)
1417 {
1418 struct game_drawstate *ds = snew(struct game_drawstate);
1419 struct bbox bb = find_bbox(&state->params);
1420
1421 ds->ox = (int)(-(bb.l - state->solid->border) * GRID_SCALE);
1422 ds->oy = (int)(-(bb.u - state->solid->border) * GRID_SCALE);
1423
1424 return ds;
1425 }
1426
1427 static void game_free_drawstate(game_drawstate *ds)
1428 {
1429 sfree(ds);
1430 }
1431
1432 static void game_redraw(frontend *fe, game_drawstate *ds, game_state *oldstate,
1433 game_state *state, int dir, game_ui *ui,
1434 float animtime, float flashtime)
1435 {
1436 int i, j;
1437 struct bbox bb = find_bbox(&state->params);
1438 struct solid *poly;
1439 int *pkey, *gkey;
1440 float t[3];
1441 float angle;
1442 game_state *newstate;
1443 int square;
1444
1445 draw_rect(fe, 0, 0, (int)((bb.r-bb.l+2.0F) * GRID_SCALE),
1446 (int)((bb.d-bb.u+2.0F) * GRID_SCALE), COL_BACKGROUND);
1447
1448 if (dir < 0) {
1449 game_state *t;
1450
1451 /*
1452 * This is an Undo. So reverse the order of the states, and
1453 * run the roll timer backwards.
1454 */
1455 assert(oldstate);
1456
1457 t = oldstate;
1458 oldstate = state;
1459 state = t;
1460
1461 animtime = ROLLTIME - animtime;
1462 }
1463
1464 if (!oldstate) {
1465 oldstate = state;
1466 angle = 0.0;
1467 square = state->current;
1468 pkey = state->dpkey;
1469 gkey = state->dgkey;
1470 } else {
1471 angle = state->angle * animtime / ROLLTIME;
1472 square = state->previous;
1473 pkey = state->spkey;
1474 gkey = state->sgkey;
1475 }
1476 newstate = state;
1477 state = oldstate;
1478
1479 for (i = 0; i < state->nsquares; i++) {
1480 int coords[8];
1481
1482 for (j = 0; j < state->squares[i].npoints; j++) {
1483 coords[2*j] = ((int)(state->squares[i].points[2*j] * GRID_SCALE)
1484 + ds->ox);
1485 coords[2*j+1] = ((int)(state->squares[i].points[2*j+1]*GRID_SCALE)
1486 + ds->oy);
1487 }
1488
1489 draw_polygon(fe, coords, state->squares[i].npoints, TRUE,
1490 state->squares[i].blue ? COL_BLUE : COL_BACKGROUND);
1491 draw_polygon(fe, coords, state->squares[i].npoints, FALSE, COL_BORDER);
1492 }
1493
1494 /*
1495 * Now compute and draw the polyhedron.
1496 */
1497 poly = transform_poly(state->solid, state->squares[square].flip,
1498 pkey[0], pkey[1], angle);
1499
1500 /*
1501 * Compute the translation required to align the two key points
1502 * on the polyhedron with the same key points on the current
1503 * face.
1504 */
1505 for (i = 0; i < 3; i++) {
1506 float tc = 0.0;
1507
1508 for (j = 0; j < 2; j++) {
1509 float grid_coord;
1510
1511 if (i < 2) {
1512 grid_coord =
1513 state->squares[square].points[gkey[j]*2+i];
1514 } else {
1515 grid_coord = 0.0;
1516 }
1517
1518 tc += (grid_coord - poly->vertices[pkey[j]*3+i]);
1519 }
1520
1521 t[i] = tc / 2;
1522 }
1523 for (i = 0; i < poly->nvertices; i++)
1524 for (j = 0; j < 3; j++)
1525 poly->vertices[i*3+j] += t[j];
1526
1527 /*
1528 * Now actually draw each face.
1529 */
1530 for (i = 0; i < poly->nfaces; i++) {
1531 float points[8];
1532 int coords[8];
1533
1534 for (j = 0; j < poly->order; j++) {
1535 int f = poly->faces[i*poly->order + j];
1536 points[j*2] = (poly->vertices[f*3+0] -
1537 poly->vertices[f*3+2] * poly->shear);
1538 points[j*2+1] = (poly->vertices[f*3+1] -
1539 poly->vertices[f*3+2] * poly->shear);
1540 }
1541
1542 for (j = 0; j < poly->order; j++) {
1543 coords[j*2] = (int)floor(points[j*2] * GRID_SCALE) + ds->ox;
1544 coords[j*2+1] = (int)floor(points[j*2+1] * GRID_SCALE) + ds->oy;
1545 }
1546
1547 /*
1548 * Find out whether these points are in a clockwise or
1549 * anticlockwise arrangement. If the latter, discard the
1550 * face because it's facing away from the viewer.
1551 *
1552 * This would involve fiddly winding-number stuff for a
1553 * general polygon, but for the simple parallelograms we'll
1554 * be seeing here, all we have to do is check whether the
1555 * corners turn right or left. So we'll take the vector
1556 * from point 0 to point 1, turn it right 90 degrees,
1557 * and check the sign of the dot product with that and the
1558 * next vector (point 1 to point 2).
1559 */
1560 {
1561 float v1x = points[2]-points[0];
1562 float v1y = points[3]-points[1];
1563 float v2x = points[4]-points[2];
1564 float v2y = points[5]-points[3];
1565 float dp = v1x * v2y - v1y * v2x;
1566
1567 if (dp <= 0)
1568 continue;
1569 }
1570
1571 draw_polygon(fe, coords, poly->order, TRUE,
1572 state->facecolours[i] ? COL_BLUE : COL_BACKGROUND);
1573 draw_polygon(fe, coords, poly->order, FALSE, COL_BORDER);
1574 }
1575 sfree(poly);
1576
1577 game_size(&state->params, &i, &j);
1578 draw_update(fe, 0, 0, i, j);
1579
1580 /*
1581 * Update the status bar.
1582 */
1583 {
1584 char statusbuf[256];
1585
1586 sprintf(statusbuf, "%sMoves: %d",
1587 (state->completed ? "COMPLETED! " : ""),
1588 (state->completed ? state->completed : state->movecount));
1589
1590 status_bar(fe, statusbuf);
1591 }
1592 }
1593
1594 static float game_anim_length(game_state *oldstate,
1595 game_state *newstate, int dir, game_ui *ui)
1596 {
1597 return ROLLTIME;
1598 }
1599
1600 static float game_flash_length(game_state *oldstate,
1601 game_state *newstate, int dir, game_ui *ui)
1602 {
1603 return 0.0F;
1604 }
1605
1606 static int game_wants_statusbar(void)
1607 {
1608 return TRUE;
1609 }
1610
1611 static int game_timing_state(game_state *state)
1612 {
1613 return TRUE;
1614 }
1615
1616 #ifdef COMBINED
1617 #define thegame cube
1618 #endif
1619
1620 const struct game thegame = {
1621 "Cube", "games.cube",
1622 default_params,
1623 game_fetch_preset,
1624 decode_params,
1625 encode_params,
1626 free_params,
1627 dup_params,
1628 TRUE, game_configure, custom_params,
1629 validate_params,
1630 new_game_desc,
1631 game_free_aux_info,
1632 validate_desc,
1633 new_game,
1634 dup_game,
1635 free_game,
1636 FALSE, solve_game,
1637 FALSE, game_text_format,
1638 new_ui,
1639 free_ui,
1640 make_move,
1641 game_size,
1642 game_colours,
1643 game_new_drawstate,
1644 game_free_drawstate,
1645 game_redraw,
1646 game_anim_length,
1647 game_flash_length,
1648 game_wants_statusbar,
1649 FALSE, game_timing_state,
1650 0, /* mouse_priorities */
1651 };