Mouse-based interface for Cube: you left-click anywhere on the grid
[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 PI 3.14159265358979323846264338327950884197169399
15
16 #define MAXVERTICES 20
17 #define MAXFACES 20
18 #define MAXORDER 4
19 struct solid {
20 int nvertices;
21 float vertices[MAXVERTICES * 3]; /* 3*npoints coordinates */
22 int order;
23 int nfaces;
24 int faces[MAXFACES * MAXORDER]; /* order*nfaces point indices */
25 float normals[MAXFACES * 3]; /* 3*npoints vector components */
26 float shear; /* isometric shear for nice drawing */
27 float border; /* border required around arena */
28 };
29
30 static const struct solid s_tetrahedron = {
31 4,
32 {
33 0.0F, -0.57735026919F, -0.20412414523F,
34 -0.5F, 0.28867513459F, -0.20412414523F,
35 0.0F, -0.0F, 0.6123724357F,
36 0.5F, 0.28867513459F, -0.20412414523F,
37 },
38 3, 4,
39 {
40 0,2,1, 3,1,2, 2,0,3, 1,3,0
41 },
42 {
43 -0.816496580928F, -0.471404520791F, 0.333333333334F,
44 0.0F, 0.942809041583F, 0.333333333333F,
45 0.816496580928F, -0.471404520791F, 0.333333333334F,
46 0.0F, 0.0F, -1.0F,
47 },
48 0.0F, 0.3F
49 };
50
51 static const struct solid s_cube = {
52 8,
53 {
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 +0.5F,-0.5F,-0.5F, +0.5F,-0.5F,+0.5F,
57 +0.5F,+0.5F,-0.5F, +0.5F,+0.5F,+0.5F,
58 },
59 4, 6,
60 {
61 0,1,3,2, 1,5,7,3, 5,4,6,7, 4,0,2,6, 0,4,5,1, 3,7,6,2
62 },
63 {
64 -1.0F,0.0F,0.0F, 0.0F,0.0F,+1.0F,
65 +1.0F,0.0F,0.0F, 0.0F,0.0F,-1.0F,
66 0.0F,-1.0F,0.0F, 0.0F,+1.0F,0.0F
67 },
68 0.3F, 0.5F
69 };
70
71 static const struct solid s_octahedron = {
72 6,
73 {
74 -0.5F, -0.28867513459472505F, 0.4082482904638664F,
75 0.5F, 0.28867513459472505F, -0.4082482904638664F,
76 -0.5F, 0.28867513459472505F, -0.4082482904638664F,
77 0.5F, -0.28867513459472505F, 0.4082482904638664F,
78 0.0F, -0.57735026918945009F, -0.4082482904638664F,
79 0.0F, 0.57735026918945009F, 0.4082482904638664F,
80 },
81 3, 8,
82 {
83 4,0,2, 0,5,2, 0,4,3, 5,0,3, 1,4,2, 5,1,2, 4,1,3, 1,5,3
84 },
85 {
86 -0.816496580928F, -0.471404520791F, -0.333333333334F,
87 -0.816496580928F, 0.471404520791F, 0.333333333334F,
88 0.0F, -0.942809041583F, 0.333333333333F,
89 0.0F, 0.0F, 1.0F,
90 0.0F, 0.0F, -1.0F,
91 0.0F, 0.942809041583F, -0.333333333333F,
92 0.816496580928F, -0.471404520791F, -0.333333333334F,
93 0.816496580928F, 0.471404520791F, 0.333333333334F,
94 },
95 0.0F, 0.5F
96 };
97
98 static const struct solid s_icosahedron = {
99 12,
100 {
101 0.0F, 0.57735026919F, 0.75576131408F,
102 0.0F, -0.93417235896F, 0.17841104489F,
103 0.0F, 0.93417235896F, -0.17841104489F,
104 0.0F, -0.57735026919F, -0.75576131408F,
105 -0.5F, -0.28867513459F, 0.75576131408F,
106 -0.5F, 0.28867513459F, -0.75576131408F,
107 0.5F, -0.28867513459F, 0.75576131408F,
108 0.5F, 0.28867513459F, -0.75576131408F,
109 -0.80901699437F, 0.46708617948F, 0.17841104489F,
110 0.80901699437F, 0.46708617948F, 0.17841104489F,
111 -0.80901699437F, -0.46708617948F, -0.17841104489F,
112 0.80901699437F, -0.46708617948F, -0.17841104489F,
113 },
114 3, 20,
115 {
116 8,0,2, 0,9,2, 1,10,3, 11,1,3, 0,4,6,
117 4,1,6, 5,2,7, 3,5,7, 4,8,10, 8,5,10,
118 9,6,11, 7,9,11, 0,8,4, 9,0,6, 10,1,4,
119 1,11,6, 8,2,5, 2,9,7, 3,10,5, 11,3,7,
120 },
121 {
122 -0.356822089773F, 0.87267799625F, 0.333333333333F,
123 0.356822089773F, 0.87267799625F, 0.333333333333F,
124 -0.356822089773F, -0.87267799625F, -0.333333333333F,
125 0.356822089773F, -0.87267799625F, -0.333333333333F,
126 -0.0F, 0.0F, 1.0F,
127 0.0F, -0.666666666667F, 0.745355992501F,
128 0.0F, 0.666666666667F, -0.745355992501F,
129 0.0F, 0.0F, -1.0F,
130 -0.934172358963F, -0.12732200375F, 0.333333333333F,
131 -0.934172358963F, 0.12732200375F, -0.333333333333F,
132 0.934172358963F, -0.12732200375F, 0.333333333333F,
133 0.934172358963F, 0.12732200375F, -0.333333333333F,
134 -0.57735026919F, 0.333333333334F, 0.745355992501F,
135 0.57735026919F, 0.333333333334F, 0.745355992501F,
136 -0.57735026919F, -0.745355992501F, 0.333333333334F,
137 0.57735026919F, -0.745355992501F, 0.333333333334F,
138 -0.57735026919F, 0.745355992501F, -0.333333333334F,
139 0.57735026919F, 0.745355992501F, -0.333333333334F,
140 -0.57735026919F, -0.333333333334F, -0.745355992501F,
141 0.57735026919F, -0.333333333334F, -0.745355992501F,
142 },
143 0.0F, 0.8F
144 };
145
146 enum {
147 TETRAHEDRON, CUBE, OCTAHEDRON, ICOSAHEDRON
148 };
149 static const struct solid *solids[] = {
150 &s_tetrahedron, &s_cube, &s_octahedron, &s_icosahedron
151 };
152
153 enum {
154 COL_BACKGROUND,
155 COL_BORDER,
156 COL_BLUE,
157 NCOLOURS
158 };
159
160 enum { LEFT, RIGHT, UP, DOWN, UP_LEFT, UP_RIGHT, DOWN_LEFT, DOWN_RIGHT };
161
162 #define GRID_SCALE 48.0F
163 #define ROLLTIME 0.13F
164
165 #define SQ(x) ( (x) * (x) )
166
167 #define MATMUL(ra,m,a) do { \
168 float rx, ry, rz, xx = (a)[0], yy = (a)[1], zz = (a)[2], *mat = (m); \
169 rx = mat[0] * xx + mat[3] * yy + mat[6] * zz; \
170 ry = mat[1] * xx + mat[4] * yy + mat[7] * zz; \
171 rz = mat[2] * xx + mat[5] * yy + mat[8] * zz; \
172 (ra)[0] = rx; (ra)[1] = ry; (ra)[2] = rz; \
173 } while (0)
174
175 #define APPROXEQ(x,y) ( SQ(x-y) < 0.1 )
176
177 struct grid_square {
178 float x, y;
179 int npoints;
180 float points[8]; /* maximum */
181 int directions[8]; /* bit masks showing point pairs */
182 int flip;
183 int blue;
184 int tetra_class;
185 };
186
187 struct game_params {
188 int solid;
189 /*
190 * Grid dimensions. For a square grid these are width and
191 * height respectively; otherwise the grid is a hexagon, with
192 * the top side and the two lower diagonals having length d1
193 * and the remaining three sides having length d2 (so that
194 * d1==d2 gives a regular hexagon, and d2==0 gives a triangle).
195 */
196 int d1, d2;
197 };
198
199 struct game_state {
200 struct game_params params;
201 const struct solid *solid;
202 int *facecolours;
203 struct grid_square *squares;
204 int nsquares;
205 int current; /* index of current grid square */
206 int sgkey[2]; /* key-point indices into grid sq */
207 int dgkey[2]; /* key-point indices into grid sq */
208 int spkey[2]; /* key-point indices into polyhedron */
209 int dpkey[2]; /* key-point indices into polyhedron */
210 int previous;
211 float angle;
212 int completed;
213 int movecount;
214 };
215
216 static game_params *default_params(void)
217 {
218 game_params *ret = snew(game_params);
219
220 ret->solid = CUBE;
221 ret->d1 = 4;
222 ret->d2 = 4;
223
224 return ret;
225 }
226
227 static int game_fetch_preset(int i, char **name, game_params **params)
228 {
229 game_params *ret = snew(game_params);
230 char *str;
231
232 switch (i) {
233 case 0:
234 str = "Cube";
235 ret->solid = CUBE;
236 ret->d1 = 4;
237 ret->d2 = 4;
238 break;
239 case 1:
240 str = "Tetrahedron";
241 ret->solid = TETRAHEDRON;
242 ret->d1 = 1;
243 ret->d2 = 2;
244 break;
245 case 2:
246 str = "Octahedron";
247 ret->solid = OCTAHEDRON;
248 ret->d1 = 2;
249 ret->d2 = 2;
250 break;
251 case 3:
252 str = "Icosahedron";
253 ret->solid = ICOSAHEDRON;
254 ret->d1 = 3;
255 ret->d2 = 3;
256 break;
257 default:
258 sfree(ret);
259 return FALSE;
260 }
261
262 *name = dupstr(str);
263 *params = ret;
264 return TRUE;
265 }
266
267 static void free_params(game_params *params)
268 {
269 sfree(params);
270 }
271
272 static game_params *dup_params(game_params *params)
273 {
274 game_params *ret = snew(game_params);
275 *ret = *params; /* structure copy */
276 return ret;
277 }
278
279 static void decode_params(game_params *ret, char const *string)
280 {
281 switch (*string) {
282 case 't': ret->solid = TETRAHEDRON; string++; break;
283 case 'c': ret->solid = CUBE; string++; break;
284 case 'o': ret->solid = OCTAHEDRON; string++; break;
285 case 'i': ret->solid = ICOSAHEDRON; string++; break;
286 default: break;
287 }
288 ret->d1 = ret->d2 = atoi(string);
289 while (*string && isdigit(*string)) string++;
290 if (*string == 'x') {
291 string++;
292 ret->d2 = atoi(string);
293 }
294 }
295
296 static char *encode_params(game_params *params, int full)
297 {
298 char data[256];
299
300 assert(params->solid >= 0 && params->solid < 4);
301 sprintf(data, "%c%dx%d", "tcoi"[params->solid], params->d1, params->d2);
302
303 return dupstr(data);
304 }
305
306 static void enum_grid_squares(game_params *params,
307 void (*callback)(void *, struct grid_square *),
308 void *ctx)
309 {
310 const struct solid *solid = solids[params->solid];
311
312 if (solid->order == 4) {
313 int x, y;
314
315 for (y = 0; y < params->d2; y++)
316 for (x = 0; x < params->d1; x++) {
317 struct grid_square sq;
318
319 sq.x = (float)x;
320 sq.y = (float)y;
321 sq.points[0] = x - 0.5F;
322 sq.points[1] = y - 0.5F;
323 sq.points[2] = x - 0.5F;
324 sq.points[3] = y + 0.5F;
325 sq.points[4] = x + 0.5F;
326 sq.points[5] = y + 0.5F;
327 sq.points[6] = x + 0.5F;
328 sq.points[7] = y - 0.5F;
329 sq.npoints = 4;
330
331 sq.directions[LEFT] = 0x03; /* 0,1 */
332 sq.directions[RIGHT] = 0x0C; /* 2,3 */
333 sq.directions[UP] = 0x09; /* 0,3 */
334 sq.directions[DOWN] = 0x06; /* 1,2 */
335 sq.directions[UP_LEFT] = 0; /* no diagonals in a square */
336 sq.directions[UP_RIGHT] = 0; /* no diagonals in a square */
337 sq.directions[DOWN_LEFT] = 0; /* no diagonals in a square */
338 sq.directions[DOWN_RIGHT] = 0; /* no diagonals in a square */
339
340 sq.flip = FALSE;
341
342 /*
343 * This is supremely irrelevant, but just to avoid
344 * having any uninitialised structure members...
345 */
346 sq.tetra_class = 0;
347
348 callback(ctx, &sq);
349 }
350 } else {
351 int row, rowlen, other, i, firstix = -1;
352 float theight = (float)(sqrt(3) / 2.0);
353
354 for (row = 0; row < params->d1 + params->d2; row++) {
355 if (row < params->d2) {
356 other = +1;
357 rowlen = row + params->d1;
358 } else {
359 other = -1;
360 rowlen = 2*params->d2 + params->d1 - row;
361 }
362
363 /*
364 * There are `rowlen' down-pointing triangles.
365 */
366 for (i = 0; i < rowlen; i++) {
367 struct grid_square sq;
368 int ix;
369 float x, y;
370
371 ix = (2 * i - (rowlen-1));
372 x = ix * 0.5F;
373 y = theight * row;
374 sq.x = x;
375 sq.y = y + theight / 3;
376 sq.points[0] = x - 0.5F;
377 sq.points[1] = y;
378 sq.points[2] = x;
379 sq.points[3] = y + theight;
380 sq.points[4] = x + 0.5F;
381 sq.points[5] = y;
382 sq.npoints = 3;
383
384 sq.directions[LEFT] = 0x03; /* 0,1 */
385 sq.directions[RIGHT] = 0x06; /* 1,2 */
386 sq.directions[UP] = 0x05; /* 0,2 */
387 sq.directions[DOWN] = 0; /* invalid move */
388
389 /*
390 * Down-pointing triangle: both the up diagonals go
391 * up, and the down ones go left and right.
392 */
393 sq.directions[UP_LEFT] = sq.directions[UP_RIGHT] =
394 sq.directions[UP];
395 sq.directions[DOWN_LEFT] = sq.directions[LEFT];
396 sq.directions[DOWN_RIGHT] = sq.directions[RIGHT];
397
398 sq.flip = TRUE;
399
400 if (firstix < 0)
401 firstix = ix & 3;
402 ix -= firstix;
403 sq.tetra_class = ((row+(ix&1)) & 2) ^ (ix & 3);
404
405 callback(ctx, &sq);
406 }
407
408 /*
409 * There are `rowlen+other' up-pointing triangles.
410 */
411 for (i = 0; i < rowlen+other; i++) {
412 struct grid_square sq;
413 int ix;
414 float x, y;
415
416 ix = (2 * i - (rowlen+other-1));
417 x = ix * 0.5F;
418 y = theight * row;
419 sq.x = x;
420 sq.y = y + 2*theight / 3;
421 sq.points[0] = x + 0.5F;
422 sq.points[1] = y + theight;
423 sq.points[2] = x;
424 sq.points[3] = y;
425 sq.points[4] = x - 0.5F;
426 sq.points[5] = y + theight;
427 sq.npoints = 3;
428
429 sq.directions[LEFT] = 0x06; /* 1,2 */
430 sq.directions[RIGHT] = 0x03; /* 0,1 */
431 sq.directions[DOWN] = 0x05; /* 0,2 */
432 sq.directions[UP] = 0; /* invalid move */
433
434 /*
435 * Up-pointing triangle: both the down diagonals go
436 * down, and the up ones go left and right.
437 */
438 sq.directions[DOWN_LEFT] = sq.directions[DOWN_RIGHT] =
439 sq.directions[DOWN];
440 sq.directions[UP_LEFT] = sq.directions[LEFT];
441 sq.directions[UP_RIGHT] = sq.directions[RIGHT];
442
443 sq.flip = FALSE;
444
445 if (firstix < 0)
446 firstix = (ix - 1) & 3;
447 ix -= firstix;
448 sq.tetra_class = ((row+(ix&1)) & 2) ^ (ix & 3);
449
450 callback(ctx, &sq);
451 }
452 }
453 }
454 }
455
456 static int grid_area(int d1, int d2, int order)
457 {
458 /*
459 * An NxM grid of squares has NM squares in it.
460 *
461 * A grid of triangles with dimensions A and B has a total of
462 * A^2 + B^2 + 4AB triangles in it. (You can divide it up into
463 * a side-A triangle containing A^2 subtriangles, a side-B
464 * triangle containing B^2, and two congruent parallelograms,
465 * each with side lengths A and B, each therefore containing AB
466 * two-triangle rhombuses.)
467 */
468 if (order == 4)
469 return d1 * d2;
470 else
471 return d1*d1 + d2*d2 + 4*d1*d2;
472 }
473
474 static config_item *game_configure(game_params *params)
475 {
476 config_item *ret = snewn(4, config_item);
477 char buf[80];
478
479 ret[0].name = "Type of solid";
480 ret[0].type = C_CHOICES;
481 ret[0].sval = ":Tetrahedron:Cube:Octahedron:Icosahedron";
482 ret[0].ival = params->solid;
483
484 ret[1].name = "Width / top";
485 ret[1].type = C_STRING;
486 sprintf(buf, "%d", params->d1);
487 ret[1].sval = dupstr(buf);
488 ret[1].ival = 0;
489
490 ret[2].name = "Height / bottom";
491 ret[2].type = C_STRING;
492 sprintf(buf, "%d", params->d2);
493 ret[2].sval = dupstr(buf);
494 ret[2].ival = 0;
495
496 ret[3].name = NULL;
497 ret[3].type = C_END;
498 ret[3].sval = NULL;
499 ret[3].ival = 0;
500
501 return ret;
502 }
503
504 static game_params *custom_params(config_item *cfg)
505 {
506 game_params *ret = snew(game_params);
507
508 ret->solid = cfg[0].ival;
509 ret->d1 = atoi(cfg[1].sval);
510 ret->d2 = atoi(cfg[2].sval);
511
512 return ret;
513 }
514
515 static void count_grid_square_callback(void *ctx, struct grid_square *sq)
516 {
517 int *classes = (int *)ctx;
518 int thisclass;
519
520 if (classes[4] == 4)
521 thisclass = sq->tetra_class;
522 else if (classes[4] == 2)
523 thisclass = sq->flip;
524 else
525 thisclass = 0;
526
527 classes[thisclass]++;
528 }
529
530 static char *validate_params(game_params *params)
531 {
532 int classes[5];
533 int i;
534
535 if (params->solid < 0 || params->solid >= lenof(solids))
536 return "Unrecognised solid type";
537
538 if (solids[params->solid]->order == 4) {
539 if (params->d1 <= 0 || params->d2 <= 0)
540 return "Both grid dimensions must be greater than zero";
541 } else {
542 if (params->d1 <= 0 && params->d2 <= 0)
543 return "At least one grid dimension must be greater than zero";
544 }
545
546 for (i = 0; i < 4; i++)
547 classes[i] = 0;
548 if (params->solid == TETRAHEDRON)
549 classes[4] = 4;
550 else if (params->solid == OCTAHEDRON)
551 classes[4] = 2;
552 else
553 classes[4] = 1;
554 enum_grid_squares(params, count_grid_square_callback, classes);
555
556 for (i = 0; i < classes[4]; i++)
557 if (classes[i] < solids[params->solid]->nfaces / classes[4])
558 return "Not enough grid space to place all blue faces";
559
560 if (grid_area(params->d1, params->d2, solids[params->solid]->order) <
561 solids[params->solid]->nfaces + 1)
562 return "Not enough space to place the solid on an empty square";
563
564 return NULL;
565 }
566
567 struct grid_data {
568 int *gridptrs[4];
569 int nsquares[4];
570 int nclasses;
571 int squareindex;
572 };
573
574 static void classify_grid_square_callback(void *ctx, struct grid_square *sq)
575 {
576 struct grid_data *data = (struct grid_data *)ctx;
577 int thisclass;
578
579 if (data->nclasses == 4)
580 thisclass = sq->tetra_class;
581 else if (data->nclasses == 2)
582 thisclass = sq->flip;
583 else
584 thisclass = 0;
585
586 data->gridptrs[thisclass][data->nsquares[thisclass]++] =
587 data->squareindex++;
588 }
589
590 static char *new_game_desc(game_params *params, random_state *rs,
591 game_aux_info **aux, int interactive)
592 {
593 struct grid_data data;
594 int i, j, k, m, area, facesperclass;
595 int *flags;
596 char *desc, *p;
597
598 /*
599 * Enumerate the grid squares, dividing them into equivalence
600 * classes as appropriate. (For the tetrahedron, there is one
601 * equivalence class for each face; for the octahedron there
602 * are two classes; for the other two solids there's only one.)
603 */
604
605 area = grid_area(params->d1, params->d2, solids[params->solid]->order);
606 if (params->solid == TETRAHEDRON)
607 data.nclasses = 4;
608 else if (params->solid == OCTAHEDRON)
609 data.nclasses = 2;
610 else
611 data.nclasses = 1;
612 data.gridptrs[0] = snewn(data.nclasses * area, int);
613 for (i = 0; i < data.nclasses; i++) {
614 data.gridptrs[i] = data.gridptrs[0] + i * area;
615 data.nsquares[i] = 0;
616 }
617 data.squareindex = 0;
618 enum_grid_squares(params, classify_grid_square_callback, &data);
619
620 facesperclass = solids[params->solid]->nfaces / data.nclasses;
621
622 for (i = 0; i < data.nclasses; i++)
623 assert(data.nsquares[i] >= facesperclass);
624 assert(data.squareindex == area);
625
626 /*
627 * So now we know how many faces to allocate in each class. Get
628 * on with it.
629 */
630 flags = snewn(area, int);
631 for (i = 0; i < area; i++)
632 flags[i] = FALSE;
633
634 for (i = 0; i < data.nclasses; i++) {
635 for (j = 0; j < facesperclass; j++) {
636 int n = random_upto(rs, data.nsquares[i]);
637
638 assert(!flags[data.gridptrs[i][n]]);
639 flags[data.gridptrs[i][n]] = TRUE;
640
641 /*
642 * Move everything else up the array. I ought to use a
643 * better data structure for this, but for such small
644 * numbers it hardly seems worth the effort.
645 */
646 while (n < data.nsquares[i]-1) {
647 data.gridptrs[i][n] = data.gridptrs[i][n+1];
648 n++;
649 }
650 data.nsquares[i]--;
651 }
652 }
653
654 /*
655 * Now we know precisely which squares are blue. Encode this
656 * information in hex. While we're looping over this, collect
657 * the non-blue squares into a list in the now-unused gridptrs
658 * array.
659 */
660 desc = snewn(area / 4 + 40, char);
661 p = desc;
662 j = 0;
663 k = 8;
664 m = 0;
665 for (i = 0; i < area; i++) {
666 if (flags[i]) {
667 j |= k;
668 } else {
669 data.gridptrs[0][m++] = i;
670 }
671 k >>= 1;
672 if (!k) {
673 *p++ = "0123456789ABCDEF"[j];
674 k = 8;
675 j = 0;
676 }
677 }
678 if (k != 8)
679 *p++ = "0123456789ABCDEF"[j];
680
681 /*
682 * Choose a non-blue square for the polyhedron.
683 */
684 sprintf(p, ",%d", data.gridptrs[0][random_upto(rs, m)]);
685
686 sfree(data.gridptrs[0]);
687 sfree(flags);
688
689 return desc;
690 }
691
692 static void game_free_aux_info(game_aux_info *aux)
693 {
694 assert(!"Shouldn't happen");
695 }
696
697 static void add_grid_square_callback(void *ctx, struct grid_square *sq)
698 {
699 game_state *state = (game_state *)ctx;
700
701 state->squares[state->nsquares] = *sq; /* structure copy */
702 state->squares[state->nsquares].blue = FALSE;
703 state->nsquares++;
704 }
705
706 static int lowest_face(const struct solid *solid)
707 {
708 int i, j, best;
709 float zmin;
710
711 best = 0;
712 zmin = 0.0;
713 for (i = 0; i < solid->nfaces; i++) {
714 float z = 0;
715
716 for (j = 0; j < solid->order; j++) {
717 int f = solid->faces[i*solid->order + j];
718 z += solid->vertices[f*3+2];
719 }
720
721 if (i == 0 || zmin > z) {
722 zmin = z;
723 best = i;
724 }
725 }
726
727 return best;
728 }
729
730 static int align_poly(const struct solid *solid, struct grid_square *sq,
731 int *pkey)
732 {
733 float zmin;
734 int i, j;
735 int flip = (sq->flip ? -1 : +1);
736
737 /*
738 * First, find the lowest z-coordinate present in the solid.
739 */
740 zmin = 0.0;
741 for (i = 0; i < solid->nvertices; i++)
742 if (zmin > solid->vertices[i*3+2])
743 zmin = solid->vertices[i*3+2];
744
745 /*
746 * Now go round the grid square. For each point in the grid
747 * square, we're looking for a point of the polyhedron with the
748 * same x- and y-coordinates (relative to the square's centre),
749 * and z-coordinate equal to zmin (near enough).
750 */
751 for (j = 0; j < sq->npoints; j++) {
752 int matches, index;
753
754 matches = 0;
755 index = -1;
756
757 for (i = 0; i < solid->nvertices; i++) {
758 float dist = 0;
759
760 dist += SQ(solid->vertices[i*3+0] * flip - sq->points[j*2+0] + sq->x);
761 dist += SQ(solid->vertices[i*3+1] * flip - sq->points[j*2+1] + sq->y);
762 dist += SQ(solid->vertices[i*3+2] - zmin);
763
764 if (dist < 0.1) {
765 matches++;
766 index = i;
767 }
768 }
769
770 if (matches != 1 || index < 0)
771 return FALSE;
772 pkey[j] = index;
773 }
774
775 return TRUE;
776 }
777
778 static void flip_poly(struct solid *solid, int flip)
779 {
780 int i;
781
782 if (flip) {
783 for (i = 0; i < solid->nvertices; i++) {
784 solid->vertices[i*3+0] *= -1;
785 solid->vertices[i*3+1] *= -1;
786 }
787 for (i = 0; i < solid->nfaces; i++) {
788 solid->normals[i*3+0] *= -1;
789 solid->normals[i*3+1] *= -1;
790 }
791 }
792 }
793
794 static struct solid *transform_poly(const struct solid *solid, int flip,
795 int key0, int key1, float angle)
796 {
797 struct solid *ret = snew(struct solid);
798 float vx, vy, ax, ay;
799 float vmatrix[9], amatrix[9], vmatrix2[9];
800 int i;
801
802 *ret = *solid; /* structure copy */
803
804 flip_poly(ret, flip);
805
806 /*
807 * Now rotate the polyhedron through the given angle. We must
808 * rotate about the Z-axis to bring the two vertices key0 and
809 * key1 into horizontal alignment, then rotate about the
810 * X-axis, then rotate back again.
811 */
812 vx = ret->vertices[key1*3+0] - ret->vertices[key0*3+0];
813 vy = ret->vertices[key1*3+1] - ret->vertices[key0*3+1];
814 assert(APPROXEQ(vx*vx + vy*vy, 1.0));
815
816 vmatrix[0] = vx; vmatrix[3] = vy; vmatrix[6] = 0;
817 vmatrix[1] = -vy; vmatrix[4] = vx; vmatrix[7] = 0;
818 vmatrix[2] = 0; vmatrix[5] = 0; vmatrix[8] = 1;
819
820 ax = (float)cos(angle);
821 ay = (float)sin(angle);
822
823 amatrix[0] = 1; amatrix[3] = 0; amatrix[6] = 0;
824 amatrix[1] = 0; amatrix[4] = ax; amatrix[7] = ay;
825 amatrix[2] = 0; amatrix[5] = -ay; amatrix[8] = ax;
826
827 memcpy(vmatrix2, vmatrix, sizeof(vmatrix));
828 vmatrix2[1] = vy;
829 vmatrix2[3] = -vy;
830
831 for (i = 0; i < ret->nvertices; i++) {
832 MATMUL(ret->vertices + 3*i, vmatrix, ret->vertices + 3*i);
833 MATMUL(ret->vertices + 3*i, amatrix, ret->vertices + 3*i);
834 MATMUL(ret->vertices + 3*i, vmatrix2, ret->vertices + 3*i);
835 }
836 for (i = 0; i < ret->nfaces; i++) {
837 MATMUL(ret->normals + 3*i, vmatrix, ret->normals + 3*i);
838 MATMUL(ret->normals + 3*i, amatrix, ret->normals + 3*i);
839 MATMUL(ret->normals + 3*i, vmatrix2, ret->normals + 3*i);
840 }
841
842 return ret;
843 }
844
845 static char *validate_desc(game_params *params, char *desc)
846 {
847 int area = grid_area(params->d1, params->d2, solids[params->solid]->order);
848 int i, j;
849
850 i = (area + 3) / 4;
851 for (j = 0; j < i; j++) {
852 int c = desc[j];
853 if (c >= '0' && c <= '9') continue;
854 if (c >= 'A' && c <= 'F') continue;
855 if (c >= 'a' && c <= 'f') continue;
856 return "Not enough hex digits at start of string";
857 /* NB if desc[j]=='\0' that will also be caught here, so we're safe */
858 }
859
860 if (desc[i] != ',')
861 return "Expected ',' after hex digits";
862
863 i++;
864 do {
865 if (desc[i] < '0' || desc[i] > '9')
866 return "Expected decimal integer after ','";
867 i++;
868 } while (desc[i]);
869
870 return NULL;
871 }
872
873 static game_state *new_game(midend_data *me, game_params *params, char *desc)
874 {
875 game_state *state = snew(game_state);
876 int area;
877
878 state->params = *params; /* structure copy */
879 state->solid = solids[params->solid];
880
881 area = grid_area(params->d1, params->d2, state->solid->order);
882 state->squares = snewn(area, struct grid_square);
883 state->nsquares = 0;
884 enum_grid_squares(params, add_grid_square_callback, state);
885 assert(state->nsquares == area);
886
887 state->facecolours = snewn(state->solid->nfaces, int);
888 memset(state->facecolours, 0, state->solid->nfaces * sizeof(int));
889
890 /*
891 * Set up the blue squares and polyhedron position according to
892 * the game description.
893 */
894 {
895 char *p = desc;
896 int i, j, v;
897
898 j = 8;
899 v = 0;
900 for (i = 0; i < state->nsquares; i++) {
901 if (j == 8) {
902 v = *p++;
903 if (v >= '0' && v <= '9')
904 v -= '0';
905 else if (v >= 'A' && v <= 'F')
906 v -= 'A' - 10;
907 else if (v >= 'a' && v <= 'f')
908 v -= 'a' - 10;
909 else
910 break;
911 }
912 if (v & j)
913 state->squares[i].blue = TRUE;
914 j >>= 1;
915 if (j == 0)
916 j = 8;
917 }
918
919 if (*p == ',')
920 p++;
921
922 state->current = atoi(p);
923 if (state->current < 0 || state->current >= state->nsquares)
924 state->current = 0; /* got to do _something_ */
925 }
926
927 /*
928 * Align the polyhedron with its grid square and determine
929 * initial key points.
930 */
931 {
932 int pkey[4];
933 int ret;
934
935 ret = align_poly(state->solid, &state->squares[state->current], pkey);
936 assert(ret);
937
938 state->dpkey[0] = state->spkey[0] = pkey[0];
939 state->dpkey[1] = state->spkey[0] = pkey[1];
940 state->dgkey[0] = state->sgkey[0] = 0;
941 state->dgkey[1] = state->sgkey[0] = 1;
942 }
943
944 state->previous = state->current;
945 state->angle = 0.0;
946 state->completed = 0;
947 state->movecount = 0;
948
949 return state;
950 }
951
952 static game_state *dup_game(game_state *state)
953 {
954 game_state *ret = snew(game_state);
955
956 ret->params = state->params; /* structure copy */
957 ret->solid = state->solid;
958 ret->facecolours = snewn(ret->solid->nfaces, int);
959 memcpy(ret->facecolours, state->facecolours,
960 ret->solid->nfaces * sizeof(int));
961 ret->nsquares = state->nsquares;
962 ret->current = state->current;
963 ret->squares = snewn(ret->nsquares, struct grid_square);
964 memcpy(ret->squares, state->squares,
965 ret->nsquares * sizeof(struct grid_square));
966 ret->dpkey[0] = state->dpkey[0];
967 ret->dpkey[1] = state->dpkey[1];
968 ret->dgkey[0] = state->dgkey[0];
969 ret->dgkey[1] = state->dgkey[1];
970 ret->spkey[0] = state->spkey[0];
971 ret->spkey[1] = state->spkey[1];
972 ret->sgkey[0] = state->sgkey[0];
973 ret->sgkey[1] = state->sgkey[1];
974 ret->previous = state->previous;
975 ret->angle = state->angle;
976 ret->completed = state->completed;
977 ret->movecount = state->movecount;
978
979 return ret;
980 }
981
982 static void free_game(game_state *state)
983 {
984 sfree(state);
985 }
986
987 static game_state *solve_game(game_state *state, game_aux_info *aux,
988 char **error)
989 {
990 return NULL;
991 }
992
993 static char *game_text_format(game_state *state)
994 {
995 return NULL;
996 }
997
998 static game_ui *new_ui(game_state *state)
999 {
1000 return NULL;
1001 }
1002
1003 static void free_ui(game_ui *ui)
1004 {
1005 }
1006
1007 struct game_drawstate {
1008 int ox, oy; /* pixel position of float origin */
1009 };
1010
1011 static game_state *make_move(game_state *from, game_ui *ui, game_drawstate *ds,
1012 int x, int y, int button)
1013 {
1014 int direction;
1015 int pkey[2], skey[2], dkey[2];
1016 float points[4];
1017 game_state *ret;
1018 float angle;
1019 int i, j, dest, mask;
1020 struct solid *poly;
1021
1022 button = button & (~MOD_MASK | MOD_NUM_KEYPAD);
1023
1024 /*
1025 * Moves can be made with the cursor keys or numeric keypad, or
1026 * alternatively you can left-click and the polyhedron will
1027 * move in the general direction of the mouse pointer.
1028 */
1029 if (button == CURSOR_UP || button == (MOD_NUM_KEYPAD | '8'))
1030 direction = UP;
1031 else if (button == CURSOR_DOWN || button == (MOD_NUM_KEYPAD | '2'))
1032 direction = DOWN;
1033 else if (button == CURSOR_LEFT || button == (MOD_NUM_KEYPAD | '4'))
1034 direction = LEFT;
1035 else if (button == CURSOR_RIGHT || button == (MOD_NUM_KEYPAD | '6'))
1036 direction = RIGHT;
1037 else if (button == (MOD_NUM_KEYPAD | '7'))
1038 direction = UP_LEFT;
1039 else if (button == (MOD_NUM_KEYPAD | '1'))
1040 direction = DOWN_LEFT;
1041 else if (button == (MOD_NUM_KEYPAD | '9'))
1042 direction = UP_RIGHT;
1043 else if (button == (MOD_NUM_KEYPAD | '3'))
1044 direction = DOWN_RIGHT;
1045 else if (button == LEFT_BUTTON) {
1046 /*
1047 * Find the bearing of the click point from the current
1048 * square's centre.
1049 */
1050 int cx, cy;
1051 double angle;
1052
1053 cx = from->squares[from->current].x * GRID_SCALE + ds->ox;
1054 cy = from->squares[from->current].y * GRID_SCALE + ds->oy;
1055
1056 if (x == cx && y == cy)
1057 return NULL; /* clicked in exact centre! */
1058 angle = atan2(y - cy, x - cx);
1059
1060 /*
1061 * There are three possibilities.
1062 *
1063 * - This square is a square, so we choose between UP,
1064 * DOWN, LEFT and RIGHT by dividing the available angle
1065 * at the 45-degree points.
1066 *
1067 * - This square is an up-pointing triangle, so we choose
1068 * between DOWN, LEFT and RIGHT by dividing into
1069 * 120-degree arcs.
1070 *
1071 * - This square is a down-pointing triangle, so we choose
1072 * between UP, LEFT and RIGHT in the inverse manner.
1073 *
1074 * Don't forget that since our y-coordinates increase
1075 * downwards, `angle' is measured _clockwise_ from the
1076 * x-axis, not anticlockwise as most mathematicians would
1077 * instinctively assume.
1078 */
1079 if (from->squares[from->current].npoints == 4) {
1080 /* Square. */
1081 if (fabs(angle) > 3*PI/4)
1082 direction = LEFT;
1083 else if (fabs(angle) < PI/4)
1084 direction = RIGHT;
1085 else if (angle > 0)
1086 direction = DOWN;
1087 else
1088 direction = UP;
1089 } else if (from->squares[from->current].directions[UP] == 0) {
1090 /* Up-pointing triangle. */
1091 if (angle < -PI/2 || angle > 5*PI/6)
1092 direction = LEFT;
1093 else if (angle > PI/6)
1094 direction = DOWN;
1095 else
1096 direction = RIGHT;
1097 } else {
1098 /* Down-pointing triangle. */
1099 assert(from->squares[from->current].directions[DOWN] == 0);
1100 if (angle > PI/2 || angle < -5*PI/6)
1101 direction = LEFT;
1102 else if (angle < -PI/6)
1103 direction = UP;
1104 else
1105 direction = RIGHT;
1106 }
1107 } else
1108 return NULL;
1109
1110 /*
1111 * Find the two points in the current grid square which
1112 * correspond to this move.
1113 */
1114 mask = from->squares[from->current].directions[direction];
1115 if (mask == 0)
1116 return NULL;
1117 for (i = j = 0; i < from->squares[from->current].npoints; i++)
1118 if (mask & (1 << i)) {
1119 points[j*2] = from->squares[from->current].points[i*2];
1120 points[j*2+1] = from->squares[from->current].points[i*2+1];
1121 skey[j] = i;
1122 j++;
1123 }
1124 assert(j == 2);
1125
1126 /*
1127 * Now find the other grid square which shares those points.
1128 * This is our move destination.
1129 */
1130 dest = -1;
1131 for (i = 0; i < from->nsquares; i++)
1132 if (i != from->current) {
1133 int match = 0;
1134 float dist;
1135
1136 for (j = 0; j < from->squares[i].npoints; j++) {
1137 dist = (SQ(from->squares[i].points[j*2] - points[0]) +
1138 SQ(from->squares[i].points[j*2+1] - points[1]));
1139 if (dist < 0.1)
1140 dkey[match++] = j;
1141 dist = (SQ(from->squares[i].points[j*2] - points[2]) +
1142 SQ(from->squares[i].points[j*2+1] - points[3]));
1143 if (dist < 0.1)
1144 dkey[match++] = j;
1145 }
1146
1147 if (match == 2) {
1148 dest = i;
1149 break;
1150 }
1151 }
1152
1153 if (dest < 0)
1154 return NULL;
1155
1156 ret = dup_game(from);
1157 ret->current = i;
1158
1159 /*
1160 * So we know what grid square we're aiming for, and we also
1161 * know the two key points (as indices in both the source and
1162 * destination grid squares) which are invariant between source
1163 * and destination.
1164 *
1165 * Next we must roll the polyhedron on to that square. So we
1166 * find the indices of the key points within the polyhedron's
1167 * vertex array, then use those in a call to transform_poly,
1168 * and align the result on the new grid square.
1169 */
1170 {
1171 int all_pkey[4];
1172 align_poly(from->solid, &from->squares[from->current], all_pkey);
1173 pkey[0] = all_pkey[skey[0]];
1174 pkey[1] = all_pkey[skey[1]];
1175 /*
1176 * Now pkey[0] corresponds to skey[0] and dkey[0], and
1177 * likewise [1].
1178 */
1179 }
1180
1181 /*
1182 * Now find the angle through which to rotate the polyhedron.
1183 * Do this by finding the two faces that share the two vertices
1184 * we've found, and taking the dot product of their normals.
1185 */
1186 {
1187 int f[2], nf = 0;
1188 float dp;
1189
1190 for (i = 0; i < from->solid->nfaces; i++) {
1191 int match = 0;
1192 for (j = 0; j < from->solid->order; j++)
1193 if (from->solid->faces[i*from->solid->order + j] == pkey[0] ||
1194 from->solid->faces[i*from->solid->order + j] == pkey[1])
1195 match++;
1196 if (match == 2) {
1197 assert(nf < 2);
1198 f[nf++] = i;
1199 }
1200 }
1201
1202 assert(nf == 2);
1203
1204 dp = 0;
1205 for (i = 0; i < 3; i++)
1206 dp += (from->solid->normals[f[0]*3+i] *
1207 from->solid->normals[f[1]*3+i]);
1208 angle = (float)acos(dp);
1209 }
1210
1211 /*
1212 * Now transform the polyhedron. We aren't entirely sure
1213 * whether we need to rotate through angle or -angle, and the
1214 * simplest way round this is to try both and see which one
1215 * aligns successfully!
1216 *
1217 * Unfortunately, _both_ will align successfully if this is a
1218 * cube, which won't tell us anything much. So for that
1219 * particular case, I resort to gross hackery: I simply negate
1220 * the angle before trying the alignment, depending on the
1221 * direction. Which directions work which way is determined by
1222 * pure trial and error. I said it was gross :-/
1223 */
1224 {
1225 int all_pkey[4];
1226 int success;
1227
1228 if (from->solid->order == 4 && direction == UP)
1229 angle = -angle; /* HACK */
1230
1231 poly = transform_poly(from->solid,
1232 from->squares[from->current].flip,
1233 pkey[0], pkey[1], angle);
1234 flip_poly(poly, from->squares[ret->current].flip);
1235 success = align_poly(poly, &from->squares[ret->current], all_pkey);
1236
1237 if (!success) {
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 draw_update(fe, 0, 0, (int)((bb.r-bb.l+2.0F) * GRID_SCALE),
1578 (int)((bb.d-bb.u+2.0F) * GRID_SCALE));
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 };