2 * (c) Lambros Lambrou 2008
4 * Code for working with general grids, which can be any planar graph
5 * with faces, edges and vertices (dots). Includes generators for a few
6 * types of grid, including square, hexagonal, triangular and others.
20 /* Debugging options */
26 /* ----------------------------------------------------------------------
27 * Deallocate or dereference a grid
29 void grid_free(grid *g)
34 if (g->refcount == 0) {
36 for (i = 0; i < g->num_faces; i++) {
37 sfree(g->faces[i].dots);
38 sfree(g->faces[i].edges);
40 for (i = 0; i < g->num_dots; i++) {
41 sfree(g->dots[i].faces);
42 sfree(g->dots[i].edges);
51 /* Used by the other grid generators. Create a brand new grid with nothing
52 * initialised (all lists are NULL) */
53 static grid *grid_new(void)
59 g->num_faces = g->num_edges = g->num_dots = 0;
61 g->lowest_x = g->lowest_y = g->highest_x = g->highest_y = 0;
65 /* Helper function to calculate perpendicular distance from
66 * a point P to a line AB. A and B mustn't be equal here.
68 * Well-known formula for area A of a triangle:
70 * 2A = determinant of matrix | px ax bx |
73 * Also well-known: 2A = base * height
74 * = perpendicular distance * line-length.
76 * Combining gives: distance = determinant / line-length(a,b)
78 static double point_line_distance(long px, long py,
82 long det = ax*by - bx*ay + bx*py - px*by + px*ay - ax*py;
85 len = sqrt(SQ(ax - bx) + SQ(ay - by));
89 /* Determine nearest edge to where the user clicked.
90 * (x, y) is the clicked location, converted to grid coordinates.
91 * Returns the nearest edge, or NULL if no edge is reasonably
94 * Just judging edges by perpendicular distance is not quite right -
95 * the edge might be "off to one side". So we insist that the triangle
96 * with (x,y) has acute angles at the edge's dots.
103 * | edge2 is OK, but edge1 is not, even though
104 * | edge1 is perpendicularly closer to (x,y)
108 grid_edge *grid_nearest_edge(grid *g, int x, int y)
110 grid_edge *best_edge;
111 double best_distance = 0;
116 for (i = 0; i < g->num_edges; i++) {
117 grid_edge *e = &g->edges[i];
118 long e2; /* squared length of edge */
119 long a2, b2; /* squared lengths of other sides */
122 /* See if edge e is eligible - the triangle must have acute angles
123 * at the edge's dots.
124 * Pythagoras formula h^2 = a^2 + b^2 detects right-angles,
125 * so detect acute angles by testing for h^2 < a^2 + b^2 */
126 e2 = SQ((long)e->dot1->x - (long)e->dot2->x) + SQ((long)e->dot1->y - (long)e->dot2->y);
127 a2 = SQ((long)e->dot1->x - (long)x) + SQ((long)e->dot1->y - (long)y);
128 b2 = SQ((long)e->dot2->x - (long)x) + SQ((long)e->dot2->y - (long)y);
129 if (a2 >= e2 + b2) continue;
130 if (b2 >= e2 + a2) continue;
132 /* e is eligible so far. Now check the edge is reasonably close
133 * to where the user clicked. Don't want to toggle an edge if the
134 * click was way off the grid.
135 * There is room for experimentation here. We could check the
136 * perpendicular distance is within a certain fraction of the length
137 * of the edge. That amounts to testing a rectangular region around
139 * Alternatively, we could check that the angle at the point is obtuse.
140 * That would amount to testing a circular region with the edge as
142 dist = point_line_distance((long)x, (long)y,
143 (long)e->dot1->x, (long)e->dot1->y,
144 (long)e->dot2->x, (long)e->dot2->y);
145 /* Is dist more than half edge length ? */
146 if (4 * SQ(dist) > e2)
149 if (best_edge == NULL || dist < best_distance) {
151 best_distance = dist;
157 /* ----------------------------------------------------------------------
162 /* Show the basic grid information, before doing grid_make_consistent */
163 static void grid_print_basic(grid *g)
165 /* TODO: Maybe we should generate an SVG image of the dots and lines
166 * of the grid here, before grid_make_consistent.
167 * Would help with debugging grid generation. */
169 printf("--- Basic Grid Data ---\n");
170 for (i = 0; i < g->num_faces; i++) {
171 grid_face *f = g->faces + i;
172 printf("Face %d: dots[", i);
174 for (j = 0; j < f->order; j++) {
175 grid_dot *d = f->dots[j];
176 printf("%s%d", j ? "," : "", (int)(d - g->dots));
181 /* Show the derived grid information, computed by grid_make_consistent */
182 static void grid_print_derived(grid *g)
186 printf("--- Derived Grid Data ---\n");
187 for (i = 0; i < g->num_edges; i++) {
188 grid_edge *e = g->edges + i;
189 printf("Edge %d: dots[%d,%d] faces[%d,%d]\n",
190 i, (int)(e->dot1 - g->dots), (int)(e->dot2 - g->dots),
191 e->face1 ? (int)(e->face1 - g->faces) : -1,
192 e->face2 ? (int)(e->face2 - g->faces) : -1);
195 for (i = 0; i < g->num_faces; i++) {
196 grid_face *f = g->faces + i;
198 printf("Face %d: faces[", i);
199 for (j = 0; j < f->order; j++) {
200 grid_edge *e = f->edges[j];
201 grid_face *f2 = (e->face1 == f) ? e->face2 : e->face1;
202 printf("%s%d", j ? "," : "", f2 ? (int)(f2 - g->faces) : -1);
207 for (i = 0; i < g->num_dots; i++) {
208 grid_dot *d = g->dots + i;
210 printf("Dot %d: dots[", i);
211 for (j = 0; j < d->order; j++) {
212 grid_edge *e = d->edges[j];
213 grid_dot *d2 = (e->dot1 == d) ? e->dot2 : e->dot1;
214 printf("%s%d", j ? "," : "", (int)(d2 - g->dots));
217 for (j = 0; j < d->order; j++) {
218 grid_face *f = d->faces[j];
219 printf("%s%d", j ? "," : "", f ? (int)(f - g->faces) : -1);
224 #endif /* DEBUG_GRID */
226 /* Helper function for building incomplete-edges list in
227 * grid_make_consistent() */
228 static int grid_edge_bydots_cmpfn(void *v1, void *v2)
234 /* Pointer subtraction is valid here, because all dots point into the
235 * same dot-list (g->dots).
236 * Edges are not "normalised" - the 2 dots could be stored in any order,
237 * so we need to take this into account when comparing edges. */
239 /* Compare first dots */
240 da = (a->dot1 < a->dot2) ? a->dot1 : a->dot2;
241 db = (b->dot1 < b->dot2) ? b->dot1 : b->dot2;
244 /* Compare last dots */
245 da = (a->dot1 < a->dot2) ? a->dot2 : a->dot1;
246 db = (b->dot1 < b->dot2) ? b->dot2 : b->dot1;
253 /* Input: grid has its dots and faces initialised:
254 * - dots have (optionally) x and y coordinates, but no edges or faces
255 * (pointers are NULL).
256 * - edges not initialised at all
257 * - faces initialised and know which dots they have (but no edges yet). The
258 * dots around each face are assumed to be clockwise.
260 * Output: grid is complete and valid with all relationships defined.
262 static void grid_make_consistent(grid *g)
265 tree234 *incomplete_edges;
266 grid_edge *next_new_edge; /* Where new edge will go into g->edges */
272 /* ====== Stage 1 ======
276 /* We know how many dots and faces there are, so we can find the exact
277 * number of edges from Euler's polyhedral formula: F + V = E + 2 .
278 * We use "-1", not "-2" here, because Euler's formula includes the
279 * infinite face, which we don't count. */
280 g->num_edges = g->num_faces + g->num_dots - 1;
281 g->edges = snewn(g->num_edges, grid_edge);
282 next_new_edge = g->edges;
284 /* Iterate over faces, and over each face's dots, generating edges as we
285 * go. As we find each new edge, we can immediately fill in the edge's
286 * dots, but only one of the edge's faces. Later on in the iteration, we
287 * will find the same edge again (unless it's on the border), but we will
288 * know the other face.
289 * For efficiency, maintain a list of the incomplete edges, sorted by
291 incomplete_edges = newtree234(grid_edge_bydots_cmpfn);
292 for (i = 0; i < g->num_faces; i++) {
293 grid_face *f = g->faces + i;
295 for (j = 0; j < f->order; j++) {
296 grid_edge e; /* fake edge for searching */
297 grid_edge *edge_found;
302 e.dot2 = f->dots[j2];
303 /* Use del234 instead of find234, because we always want to
304 * remove the edge if found */
305 edge_found = del234(incomplete_edges, &e);
307 /* This edge already added, so fill out missing face.
308 * Edge is already removed from incomplete_edges. */
309 edge_found->face2 = f;
311 assert(next_new_edge - g->edges < g->num_edges);
312 next_new_edge->dot1 = e.dot1;
313 next_new_edge->dot2 = e.dot2;
314 next_new_edge->face1 = f;
315 next_new_edge->face2 = NULL; /* potentially infinite face */
316 add234(incomplete_edges, next_new_edge);
321 freetree234(incomplete_edges);
323 /* ====== Stage 2 ======
324 * For each face, build its edge list.
327 /* Allocate space for each edge list. Can do this, because each face's
328 * edge-list is the same size as its dot-list. */
329 for (i = 0; i < g->num_faces; i++) {
330 grid_face *f = g->faces + i;
332 f->edges = snewn(f->order, grid_edge*);
333 /* Preload with NULLs, to help detect potential bugs. */
334 for (j = 0; j < f->order; j++)
338 /* Iterate over each edge, and over both its faces. Add this edge to
339 * the face's edge-list, after finding where it should go in the
341 for (i = 0; i < g->num_edges; i++) {
342 grid_edge *e = g->edges + i;
344 for (j = 0; j < 2; j++) {
345 grid_face *f = j ? e->face2 : e->face1;
347 if (f == NULL) continue;
348 /* Find one of the dots around the face */
349 for (k = 0; k < f->order; k++) {
350 if (f->dots[k] == e->dot1)
351 break; /* found dot1 */
353 assert(k != f->order); /* Must find the dot around this face */
355 /* Labelling scheme: as we walk clockwise around the face,
356 * starting at dot0 (f->dots[0]), we hit:
357 * (dot0), edge0, dot1, edge1, dot2,...
367 * Therefore, edgeK joins dotK and dot{K+1}
370 /* Around this face, either the next dot or the previous dot
371 * must be e->dot2. Otherwise the edge is wrong. */
375 if (f->dots[k2] == e->dot2) {
376 /* dot1(k) and dot2(k2) go clockwise around this face, so add
377 * this edge at position k (see diagram). */
378 assert(f->edges[k] == NULL);
382 /* Try previous dot */
386 if (f->dots[k2] == e->dot2) {
387 /* dot1(k) and dot2(k2) go anticlockwise around this face. */
388 assert(f->edges[k2] == NULL);
392 assert(!"Grid broken: bad edge-face relationship");
396 /* ====== Stage 3 ======
397 * For each dot, build its edge-list and face-list.
400 /* We don't know how many edges/faces go around each dot, so we can't
401 * allocate the right space for these lists. Pre-compute the sizes by
402 * iterating over each edge and recording a tally against each dot. */
403 for (i = 0; i < g->num_dots; i++) {
404 g->dots[i].order = 0;
406 for (i = 0; i < g->num_edges; i++) {
407 grid_edge *e = g->edges + i;
411 /* Now we have the sizes, pre-allocate the edge and face lists. */
412 for (i = 0; i < g->num_dots; i++) {
413 grid_dot *d = g->dots + i;
415 assert(d->order >= 2); /* sanity check */
416 d->edges = snewn(d->order, grid_edge*);
417 d->faces = snewn(d->order, grid_face*);
418 for (j = 0; j < d->order; j++) {
423 /* For each dot, need to find a face that touches it, so we can seed
424 * the edge-face-edge-face process around each dot. */
425 for (i = 0; i < g->num_faces; i++) {
426 grid_face *f = g->faces + i;
428 for (j = 0; j < f->order; j++) {
429 grid_dot *d = f->dots[j];
433 /* Each dot now has a face in its first slot. Generate the remaining
434 * faces and edges around the dot, by searching both clockwise and
435 * anticlockwise from the first face. Need to do both directions,
436 * because of the possibility of hitting the infinite face, which
437 * blocks progress. But there's only one such face, so we will
438 * succeed in finding every edge and face this way. */
439 for (i = 0; i < g->num_dots; i++) {
440 grid_dot *d = g->dots + i;
441 int current_face1 = 0; /* ascends clockwise */
442 int current_face2 = 0; /* descends anticlockwise */
444 /* Labelling scheme: as we walk clockwise around the dot, starting
445 * at face0 (d->faces[0]), we hit:
446 * (face0), edge0, face1, edge1, face2,...
458 * So, for example, face1 should be joined to edge0 and edge1,
459 * and those edges should appear in an anticlockwise sense around
460 * that face (see diagram). */
462 /* clockwise search */
464 grid_face *f = d->faces[current_face1];
468 /* find dot around this face */
469 for (j = 0; j < f->order; j++) {
473 assert(j != f->order); /* must find dot */
475 /* Around f, required edge is anticlockwise from the dot. See
476 * the other labelling scheme higher up, for why we subtract 1
482 d->edges[current_face1] = e; /* set edge */
484 if (current_face1 == d->order)
488 d->faces[current_face1] =
489 (e->face1 == f) ? e->face2 : e->face1;
490 if (d->faces[current_face1] == NULL)
491 break; /* cannot progress beyond infinite face */
494 /* If the clockwise search made it all the way round, don't need to
495 * bother with the anticlockwise search. */
496 if (current_face1 == d->order)
497 continue; /* this dot is complete, move on to next dot */
499 /* anticlockwise search */
501 grid_face *f = d->faces[current_face2];
505 /* find dot around this face */
506 for (j = 0; j < f->order; j++) {
510 assert(j != f->order); /* must find dot */
512 /* Around f, required edge is clockwise from the dot. */
516 if (current_face2 == -1)
517 current_face2 = d->order - 1;
518 d->edges[current_face2] = e; /* set edge */
521 if (current_face2 == current_face1)
523 d->faces[current_face2] =
524 (e->face1 == f) ? e->face2 : e->face1;
525 /* There's only 1 infinite face, so we must get all the way
526 * to current_face1 before we hit it. */
527 assert(d->faces[current_face2]);
531 /* ====== Stage 4 ======
532 * Compute other grid settings
535 /* Bounding rectangle */
536 for (i = 0; i < g->num_dots; i++) {
537 grid_dot *d = g->dots + i;
539 g->lowest_x = g->highest_x = d->x;
540 g->lowest_y = g->highest_y = d->y;
542 g->lowest_x = min(g->lowest_x, d->x);
543 g->highest_x = max(g->highest_x, d->x);
544 g->lowest_y = min(g->lowest_y, d->y);
545 g->highest_y = max(g->highest_y, d->y);
550 grid_print_derived(g);
554 /* Helpers for making grid-generation easier. These functions are only
555 * intended for use during grid generation. */
557 /* Comparison function for the (tree234) sorted dot list */
558 static int grid_point_cmp_fn(void *v1, void *v2)
563 return p2->y - p1->y;
565 return p2->x - p1->x;
567 /* Add a new face to the grid, with its dot list allocated.
568 * Assumes there's enough space allocated for the new face in grid->faces */
569 static void grid_face_add_new(grid *g, int face_size)
572 grid_face *new_face = g->faces + g->num_faces;
573 new_face->order = face_size;
574 new_face->dots = snewn(face_size, grid_dot*);
575 for (i = 0; i < face_size; i++)
576 new_face->dots[i] = NULL;
577 new_face->edges = NULL;
580 /* Assumes dot list has enough space */
581 static grid_dot *grid_dot_add_new(grid *g, int x, int y)
583 grid_dot *new_dot = g->dots + g->num_dots;
585 new_dot->edges = NULL;
586 new_dot->faces = NULL;
592 /* Retrieve a dot with these (x,y) coordinates. Either return an existing dot
593 * in the dot_list, or add a new dot to the grid (and the dot_list) and
595 * Assumes g->dots has enough capacity allocated */
596 static grid_dot *grid_get_dot(grid *g, tree234 *dot_list, int x, int y)
605 ret = find234(dot_list, &test, NULL);
609 ret = grid_dot_add_new(g, x, y);
610 add234(dot_list, ret);
614 /* Sets the last face of the grid to include this dot, at this position
615 * around the face. Assumes num_faces is at least 1 (a new face has
616 * previously been added, with the required number of dots allocated) */
617 static void grid_face_set_dot(grid *g, grid_dot *d, int position)
619 grid_face *last_face = g->faces + g->num_faces - 1;
620 last_face->dots[position] = d;
623 /* ------ Generate various types of grid ------ */
625 /* General method is to generate faces, by calculating their dot coordinates.
626 * As new faces are added, we keep track of all the dots so we can tell when
627 * a new face reuses an existing dot. For example, two squares touching at an
628 * edge would generate six unique dots: four dots from the first face, then
629 * two additional dots for the second face, because we detect the other two
630 * dots have already been taken up. This list is stored in a tree234
631 * called "points". No extra memory-allocation needed here - we store the
632 * actual grid_dot* pointers, which all point into the g->dots list.
633 * For this reason, we have to calculate coordinates in such a way as to
634 * eliminate any rounding errors, so we can detect when a dot on one
635 * face precisely lands on a dot of a different face. No floating-point
639 grid *grid_new_square(int width, int height)
645 /* Upper bounds - don't have to be exact */
646 int max_faces = width * height;
647 int max_dots = (width + 1) * (height + 1);
651 grid *g = grid_new();
653 g->faces = snewn(max_faces, grid_face);
654 g->dots = snewn(max_dots, grid_dot);
656 points = newtree234(grid_point_cmp_fn);
658 /* generate square faces */
659 for (y = 0; y < height; y++) {
660 for (x = 0; x < width; x++) {
666 grid_face_add_new(g, 4);
667 d = grid_get_dot(g, points, px, py);
668 grid_face_set_dot(g, d, 0);
669 d = grid_get_dot(g, points, px + a, py);
670 grid_face_set_dot(g, d, 1);
671 d = grid_get_dot(g, points, px + a, py + a);
672 grid_face_set_dot(g, d, 2);
673 d = grid_get_dot(g, points, px, py + a);
674 grid_face_set_dot(g, d, 3);
679 assert(g->num_faces <= max_faces);
680 assert(g->num_dots <= max_dots);
682 grid_make_consistent(g);
686 grid *grid_new_honeycomb(int width, int height)
689 /* Vector for side of hexagon - ratio is close to sqrt(3) */
693 /* Upper bounds - don't have to be exact */
694 int max_faces = width * height;
695 int max_dots = 2 * (width + 1) * (height + 1);
699 grid *g = grid_new();
701 g->faces = snewn(max_faces, grid_face);
702 g->dots = snewn(max_dots, grid_dot);
704 points = newtree234(grid_point_cmp_fn);
706 /* generate hexagonal faces */
707 for (y = 0; y < height; y++) {
708 for (x = 0; x < width; x++) {
715 grid_face_add_new(g, 6);
717 d = grid_get_dot(g, points, cx - a, cy - b);
718 grid_face_set_dot(g, d, 0);
719 d = grid_get_dot(g, points, cx + a, cy - b);
720 grid_face_set_dot(g, d, 1);
721 d = grid_get_dot(g, points, cx + 2*a, cy);
722 grid_face_set_dot(g, d, 2);
723 d = grid_get_dot(g, points, cx + a, cy + b);
724 grid_face_set_dot(g, d, 3);
725 d = grid_get_dot(g, points, cx - a, cy + b);
726 grid_face_set_dot(g, d, 4);
727 d = grid_get_dot(g, points, cx - 2*a, cy);
728 grid_face_set_dot(g, d, 5);
733 assert(g->num_faces <= max_faces);
734 assert(g->num_dots <= max_dots);
736 grid_make_consistent(g);
740 /* Doesn't use the previous method of generation, it pre-dates it!
741 * A triangular grid is just about simple enough to do by "brute force" */
742 grid *grid_new_triangular(int width, int height)
746 /* Vector for side of triangle - ratio is close to sqrt(3) */
752 /* convenient alias */
755 grid *g = grid_new();
756 g->tilesize = 18; /* adjust to your taste */
758 g->num_faces = width * height * 2;
759 g->num_dots = (width + 1) * (height + 1);
760 g->faces = snewn(g->num_faces, grid_face);
761 g->dots = snewn(g->num_dots, grid_dot);
765 for (y = 0; y <= height; y++) {
766 for (x = 0; x <= width; x++) {
767 grid_dot *d = g->dots + index;
768 /* odd rows are offset to the right */
772 d->x = x * 2 * vec_x + ((y % 2) ? vec_x : 0);
780 for (y = 0; y < height; y++) {
781 for (x = 0; x < width; x++) {
782 /* initialise two faces for this (x,y) */
783 grid_face *f1 = g->faces + index;
784 grid_face *f2 = f1 + 1;
787 f1->dots = snewn(f1->order, grid_dot*);
790 f2->dots = snewn(f2->order, grid_dot*);
792 /* face descriptions depend on whether the row-number is
795 f1->dots[0] = g->dots + y * w + x;
796 f1->dots[1] = g->dots + (y + 1) * w + x + 1;
797 f1->dots[2] = g->dots + (y + 1) * w + x;
798 f2->dots[0] = g->dots + y * w + x;
799 f2->dots[1] = g->dots + y * w + x + 1;
800 f2->dots[2] = g->dots + (y + 1) * w + x + 1;
802 f1->dots[0] = g->dots + y * w + x;
803 f1->dots[1] = g->dots + y * w + x + 1;
804 f1->dots[2] = g->dots + (y + 1) * w + x;
805 f2->dots[0] = g->dots + y * w + x + 1;
806 f2->dots[1] = g->dots + (y + 1) * w + x + 1;
807 f2->dots[2] = g->dots + (y + 1) * w + x;
813 grid_make_consistent(g);
817 grid *grid_new_snubsquare(int width, int height)
820 /* Vector for side of triangle - ratio is close to sqrt(3) */
824 /* Upper bounds - don't have to be exact */
825 int max_faces = 3 * width * height;
826 int max_dots = 2 * (width + 1) * (height + 1);
830 grid *g = grid_new();
832 g->faces = snewn(max_faces, grid_face);
833 g->dots = snewn(max_dots, grid_dot);
835 points = newtree234(grid_point_cmp_fn);
837 for (y = 0; y < height; y++) {
838 for (x = 0; x < width; x++) {
841 int px = (a + b) * x;
842 int py = (a + b) * y;
844 /* generate square faces */
845 grid_face_add_new(g, 4);
847 d = grid_get_dot(g, points, px + a, py);
848 grid_face_set_dot(g, d, 0);
849 d = grid_get_dot(g, points, px + a + b, py + a);
850 grid_face_set_dot(g, d, 1);
851 d = grid_get_dot(g, points, px + b, py + a + b);
852 grid_face_set_dot(g, d, 2);
853 d = grid_get_dot(g, points, px, py + b);
854 grid_face_set_dot(g, d, 3);
856 d = grid_get_dot(g, points, px + b, py);
857 grid_face_set_dot(g, d, 0);
858 d = grid_get_dot(g, points, px + a + b, py + b);
859 grid_face_set_dot(g, d, 1);
860 d = grid_get_dot(g, points, px + a, py + a + b);
861 grid_face_set_dot(g, d, 2);
862 d = grid_get_dot(g, points, px, py + a);
863 grid_face_set_dot(g, d, 3);
866 /* generate up/down triangles */
868 grid_face_add_new(g, 3);
870 d = grid_get_dot(g, points, px + a, py);
871 grid_face_set_dot(g, d, 0);
872 d = grid_get_dot(g, points, px, py + b);
873 grid_face_set_dot(g, d, 1);
874 d = grid_get_dot(g, points, px - a, py);
875 grid_face_set_dot(g, d, 2);
877 d = grid_get_dot(g, points, px, py + a);
878 grid_face_set_dot(g, d, 0);
879 d = grid_get_dot(g, points, px + a, py + a + b);
880 grid_face_set_dot(g, d, 1);
881 d = grid_get_dot(g, points, px - a, py + a + b);
882 grid_face_set_dot(g, d, 2);
886 /* generate left/right triangles */
888 grid_face_add_new(g, 3);
890 d = grid_get_dot(g, points, px + a, py);
891 grid_face_set_dot(g, d, 0);
892 d = grid_get_dot(g, points, px + a + b, py - a);
893 grid_face_set_dot(g, d, 1);
894 d = grid_get_dot(g, points, px + a + b, py + a);
895 grid_face_set_dot(g, d, 2);
897 d = grid_get_dot(g, points, px, py - a);
898 grid_face_set_dot(g, d, 0);
899 d = grid_get_dot(g, points, px + b, py);
900 grid_face_set_dot(g, d, 1);
901 d = grid_get_dot(g, points, px, py + a);
902 grid_face_set_dot(g, d, 2);
909 assert(g->num_faces <= max_faces);
910 assert(g->num_dots <= max_dots);
912 grid_make_consistent(g);
916 grid *grid_new_cairo(int width, int height)
919 /* Vector for side of pentagon - ratio is close to (4+sqrt(7))/3 */
923 /* Upper bounds - don't have to be exact */
924 int max_faces = 2 * width * height;
925 int max_dots = 3 * (width + 1) * (height + 1);
929 grid *g = grid_new();
931 g->faces = snewn(max_faces, grid_face);
932 g->dots = snewn(max_dots, grid_dot);
934 points = newtree234(grid_point_cmp_fn);
936 for (y = 0; y < height; y++) {
937 for (x = 0; x < width; x++) {
943 /* horizontal pentagons */
945 grid_face_add_new(g, 5);
947 d = grid_get_dot(g, points, px + a, py - b);
948 grid_face_set_dot(g, d, 0);
949 d = grid_get_dot(g, points, px + 2*b - a, py - b);
950 grid_face_set_dot(g, d, 1);
951 d = grid_get_dot(g, points, px + 2*b, py);
952 grid_face_set_dot(g, d, 2);
953 d = grid_get_dot(g, points, px + b, py + a);
954 grid_face_set_dot(g, d, 3);
955 d = grid_get_dot(g, points, px, py);
956 grid_face_set_dot(g, d, 4);
958 d = grid_get_dot(g, points, px, py);
959 grid_face_set_dot(g, d, 0);
960 d = grid_get_dot(g, points, px + b, py - a);
961 grid_face_set_dot(g, d, 1);
962 d = grid_get_dot(g, points, px + 2*b, py);
963 grid_face_set_dot(g, d, 2);
964 d = grid_get_dot(g, points, px + 2*b - a, py + b);
965 grid_face_set_dot(g, d, 3);
966 d = grid_get_dot(g, points, px + a, py + b);
967 grid_face_set_dot(g, d, 4);
970 /* vertical pentagons */
972 grid_face_add_new(g, 5);
974 d = grid_get_dot(g, points, px, py);
975 grid_face_set_dot(g, d, 0);
976 d = grid_get_dot(g, points, px + b, py + a);
977 grid_face_set_dot(g, d, 1);
978 d = grid_get_dot(g, points, px + b, py + 2*b - a);
979 grid_face_set_dot(g, d, 2);
980 d = grid_get_dot(g, points, px, py + 2*b);
981 grid_face_set_dot(g, d, 3);
982 d = grid_get_dot(g, points, px - a, py + b);
983 grid_face_set_dot(g, d, 4);
985 d = grid_get_dot(g, points, px, py);
986 grid_face_set_dot(g, d, 0);
987 d = grid_get_dot(g, points, px + a, py + b);
988 grid_face_set_dot(g, d, 1);
989 d = grid_get_dot(g, points, px, py + 2*b);
990 grid_face_set_dot(g, d, 2);
991 d = grid_get_dot(g, points, px - b, py + 2*b - a);
992 grid_face_set_dot(g, d, 3);
993 d = grid_get_dot(g, points, px - b, py + a);
994 grid_face_set_dot(g, d, 4);
1000 freetree234(points);
1001 assert(g->num_faces <= max_faces);
1002 assert(g->num_dots <= max_dots);
1004 grid_make_consistent(g);
1008 grid *grid_new_greathexagonal(int width, int height)
1011 /* Vector for side of triangle - ratio is close to sqrt(3) */
1015 /* Upper bounds - don't have to be exact */
1016 int max_faces = 6 * (width + 1) * (height + 1);
1017 int max_dots = 6 * width * height;
1021 grid *g = grid_new();
1023 g->faces = snewn(max_faces, grid_face);
1024 g->dots = snewn(max_dots, grid_dot);
1026 points = newtree234(grid_point_cmp_fn);
1028 for (y = 0; y < height; y++) {
1029 for (x = 0; x < width; x++) {
1031 /* centre of hexagon */
1032 int px = (3*a + b) * x;
1033 int py = (2*a + 2*b) * y;
1038 grid_face_add_new(g, 6);
1039 d = grid_get_dot(g, points, px - a, py - b);
1040 grid_face_set_dot(g, d, 0);
1041 d = grid_get_dot(g, points, px + a, py - b);
1042 grid_face_set_dot(g, d, 1);
1043 d = grid_get_dot(g, points, px + 2*a, py);
1044 grid_face_set_dot(g, d, 2);
1045 d = grid_get_dot(g, points, px + a, py + b);
1046 grid_face_set_dot(g, d, 3);
1047 d = grid_get_dot(g, points, px - a, py + b);
1048 grid_face_set_dot(g, d, 4);
1049 d = grid_get_dot(g, points, px - 2*a, py);
1050 grid_face_set_dot(g, d, 5);
1052 /* square below hexagon */
1053 if (y < height - 1) {
1054 grid_face_add_new(g, 4);
1055 d = grid_get_dot(g, points, px - a, py + b);
1056 grid_face_set_dot(g, d, 0);
1057 d = grid_get_dot(g, points, px + a, py + b);
1058 grid_face_set_dot(g, d, 1);
1059 d = grid_get_dot(g, points, px + a, py + 2*a + b);
1060 grid_face_set_dot(g, d, 2);
1061 d = grid_get_dot(g, points, px - a, py + 2*a + b);
1062 grid_face_set_dot(g, d, 3);
1065 /* square below right */
1066 if ((x < width - 1) && (((x % 2) == 0) || (y < height - 1))) {
1067 grid_face_add_new(g, 4);
1068 d = grid_get_dot(g, points, px + 2*a, py);
1069 grid_face_set_dot(g, d, 0);
1070 d = grid_get_dot(g, points, px + 2*a + b, py + a);
1071 grid_face_set_dot(g, d, 1);
1072 d = grid_get_dot(g, points, px + a + b, py + a + b);
1073 grid_face_set_dot(g, d, 2);
1074 d = grid_get_dot(g, points, px + a, py + b);
1075 grid_face_set_dot(g, d, 3);
1078 /* square below left */
1079 if ((x > 0) && (((x % 2) == 0) || (y < height - 1))) {
1080 grid_face_add_new(g, 4);
1081 d = grid_get_dot(g, points, px - 2*a, py);
1082 grid_face_set_dot(g, d, 0);
1083 d = grid_get_dot(g, points, px - a, py + b);
1084 grid_face_set_dot(g, d, 1);
1085 d = grid_get_dot(g, points, px - a - b, py + a + b);
1086 grid_face_set_dot(g, d, 2);
1087 d = grid_get_dot(g, points, px - 2*a - b, py + a);
1088 grid_face_set_dot(g, d, 3);
1091 /* Triangle below right */
1092 if ((x < width - 1) && (y < height - 1)) {
1093 grid_face_add_new(g, 3);
1094 d = grid_get_dot(g, points, px + a, py + b);
1095 grid_face_set_dot(g, d, 0);
1096 d = grid_get_dot(g, points, px + a + b, py + a + b);
1097 grid_face_set_dot(g, d, 1);
1098 d = grid_get_dot(g, points, px + a, py + 2*a + b);
1099 grid_face_set_dot(g, d, 2);
1102 /* Triangle below left */
1103 if ((x > 0) && (y < height - 1)) {
1104 grid_face_add_new(g, 3);
1105 d = grid_get_dot(g, points, px - a, py + b);
1106 grid_face_set_dot(g, d, 0);
1107 d = grid_get_dot(g, points, px - a, py + 2*a + b);
1108 grid_face_set_dot(g, d, 1);
1109 d = grid_get_dot(g, points, px - a - b, py + a + b);
1110 grid_face_set_dot(g, d, 2);
1115 freetree234(points);
1116 assert(g->num_faces <= max_faces);
1117 assert(g->num_dots <= max_dots);
1119 grid_make_consistent(g);
1123 grid *grid_new_octagonal(int width, int height)
1126 /* b/a approx sqrt(2) */
1130 /* Upper bounds - don't have to be exact */
1131 int max_faces = 2 * width * height;
1132 int max_dots = 4 * (width + 1) * (height + 1);
1136 grid *g = grid_new();
1138 g->faces = snewn(max_faces, grid_face);
1139 g->dots = snewn(max_dots, grid_dot);
1141 points = newtree234(grid_point_cmp_fn);
1143 for (y = 0; y < height; y++) {
1144 for (x = 0; x < width; x++) {
1147 int px = (2*a + b) * x;
1148 int py = (2*a + b) * y;
1150 grid_face_add_new(g, 8);
1151 d = grid_get_dot(g, points, px + a, py);
1152 grid_face_set_dot(g, d, 0);
1153 d = grid_get_dot(g, points, px + a + b, py);
1154 grid_face_set_dot(g, d, 1);
1155 d = grid_get_dot(g, points, px + 2*a + b, py + a);
1156 grid_face_set_dot(g, d, 2);
1157 d = grid_get_dot(g, points, px + 2*a + b, py + a + b);
1158 grid_face_set_dot(g, d, 3);
1159 d = grid_get_dot(g, points, px + a + b, py + 2*a + b);
1160 grid_face_set_dot(g, d, 4);
1161 d = grid_get_dot(g, points, px + a, py + 2*a + b);
1162 grid_face_set_dot(g, d, 5);
1163 d = grid_get_dot(g, points, px, py + a + b);
1164 grid_face_set_dot(g, d, 6);
1165 d = grid_get_dot(g, points, px, py + a);
1166 grid_face_set_dot(g, d, 7);
1169 if ((x > 0) && (y > 0)) {
1170 grid_face_add_new(g, 4);
1171 d = grid_get_dot(g, points, px, py - a);
1172 grid_face_set_dot(g, d, 0);
1173 d = grid_get_dot(g, points, px + a, py);
1174 grid_face_set_dot(g, d, 1);
1175 d = grid_get_dot(g, points, px, py + a);
1176 grid_face_set_dot(g, d, 2);
1177 d = grid_get_dot(g, points, px - a, py);
1178 grid_face_set_dot(g, d, 3);
1183 freetree234(points);
1184 assert(g->num_faces <= max_faces);
1185 assert(g->num_dots <= max_dots);
1187 grid_make_consistent(g);
1191 grid *grid_new_kites(int width, int height)
1194 /* b/a approx sqrt(3) */
1198 /* Upper bounds - don't have to be exact */
1199 int max_faces = 6 * width * height;
1200 int max_dots = 6 * (width + 1) * (height + 1);
1204 grid *g = grid_new();
1206 g->faces = snewn(max_faces, grid_face);
1207 g->dots = snewn(max_dots, grid_dot);
1209 points = newtree234(grid_point_cmp_fn);
1211 for (y = 0; y < height; y++) {
1212 for (x = 0; x < width; x++) {
1214 /* position of order-6 dot */
1220 /* kite pointing up-left */
1221 grid_face_add_new(g, 4);
1222 d = grid_get_dot(g, points, px, py);
1223 grid_face_set_dot(g, d, 0);
1224 d = grid_get_dot(g, points, px + 2*b, py);
1225 grid_face_set_dot(g, d, 1);
1226 d = grid_get_dot(g, points, px + 2*b, py + 2*a);
1227 grid_face_set_dot(g, d, 2);
1228 d = grid_get_dot(g, points, px + b, py + 3*a);
1229 grid_face_set_dot(g, d, 3);
1231 /* kite pointing up */
1232 grid_face_add_new(g, 4);
1233 d = grid_get_dot(g, points, px, py);
1234 grid_face_set_dot(g, d, 0);
1235 d = grid_get_dot(g, points, px + b, py + 3*a);
1236 grid_face_set_dot(g, d, 1);
1237 d = grid_get_dot(g, points, px, py + 4*a);
1238 grid_face_set_dot(g, d, 2);
1239 d = grid_get_dot(g, points, px - b, py + 3*a);
1240 grid_face_set_dot(g, d, 3);
1242 /* kite pointing up-right */
1243 grid_face_add_new(g, 4);
1244 d = grid_get_dot(g, points, px, py);
1245 grid_face_set_dot(g, d, 0);
1246 d = grid_get_dot(g, points, px - b, py + 3*a);
1247 grid_face_set_dot(g, d, 1);
1248 d = grid_get_dot(g, points, px - 2*b, py + 2*a);
1249 grid_face_set_dot(g, d, 2);
1250 d = grid_get_dot(g, points, px - 2*b, py);
1251 grid_face_set_dot(g, d, 3);
1253 /* kite pointing down-right */
1254 grid_face_add_new(g, 4);
1255 d = grid_get_dot(g, points, px, py);
1256 grid_face_set_dot(g, d, 0);
1257 d = grid_get_dot(g, points, px - 2*b, py);
1258 grid_face_set_dot(g, d, 1);
1259 d = grid_get_dot(g, points, px - 2*b, py - 2*a);
1260 grid_face_set_dot(g, d, 2);
1261 d = grid_get_dot(g, points, px - b, py - 3*a);
1262 grid_face_set_dot(g, d, 3);
1264 /* kite pointing down */
1265 grid_face_add_new(g, 4);
1266 d = grid_get_dot(g, points, px, py);
1267 grid_face_set_dot(g, d, 0);
1268 d = grid_get_dot(g, points, px - b, py - 3*a);
1269 grid_face_set_dot(g, d, 1);
1270 d = grid_get_dot(g, points, px, py - 4*a);
1271 grid_face_set_dot(g, d, 2);
1272 d = grid_get_dot(g, points, px + b, py - 3*a);
1273 grid_face_set_dot(g, d, 3);
1275 /* kite pointing down-left */
1276 grid_face_add_new(g, 4);
1277 d = grid_get_dot(g, points, px, py);
1278 grid_face_set_dot(g, d, 0);
1279 d = grid_get_dot(g, points, px + b, py - 3*a);
1280 grid_face_set_dot(g, d, 1);
1281 d = grid_get_dot(g, points, px + 2*b, py - 2*a);
1282 grid_face_set_dot(g, d, 2);
1283 d = grid_get_dot(g, points, px + 2*b, py);
1284 grid_face_set_dot(g, d, 3);
1288 freetree234(points);
1289 assert(g->num_faces <= max_faces);
1290 assert(g->num_dots <= max_dots);
1292 grid_make_consistent(g);
1296 grid *grid_new_floret(int width, int height)
1299 /* Vectors for sides; weird numbers needed to keep puzzle aligned with window
1300 * -py/px is close to tan(30 - atan(sqrt(3)/9))
1301 * using py=26 makes everything lean to the left, rather than right
1303 int px = 75, py = -26; /* |( 75, -26)| = 79.43 */
1304 int qx = 4*px/5, qy = -py*2; /* |( 60, 52)| = 79.40 */
1305 int rx = qx-px, ry = qy-py; /* |(-15, 78)| = 79.38 */
1307 /* Upper bounds - don't have to be exact */
1308 int max_faces = 6 * width * height;
1309 int max_dots = 9 * (width + 1) * (height + 1);
1313 grid *g = grid_new();
1314 g->tilesize = 2 * px;
1315 g->faces = snewn(max_faces, grid_face);
1316 g->dots = snewn(max_dots, grid_dot);
1318 points = newtree234(grid_point_cmp_fn);
1320 /* generate pentagonal faces */
1321 for (y = 0; y < height; y++) {
1322 for (x = 0; x < width; x++) {
1325 int cx = (6*px+3*qx)/2 * x;
1326 int cy = (4*py-5*qy) * y;
1328 cy -= (4*py-5*qy)/2;
1329 else if (y && y == height-1)
1330 continue; /* make better looking grids? try 3x3 for instance */
1332 grid_face_add_new(g, 5);
1333 d = grid_get_dot(g, points, cx , cy ); grid_face_set_dot(g, d, 0);
1334 d = grid_get_dot(g, points, cx+2*rx , cy+2*ry ); grid_face_set_dot(g, d, 1);
1335 d = grid_get_dot(g, points, cx+2*rx+qx, cy+2*ry+qy); grid_face_set_dot(g, d, 2);
1336 d = grid_get_dot(g, points, cx+2*qx+rx, cy+2*qy+ry); grid_face_set_dot(g, d, 3);
1337 d = grid_get_dot(g, points, cx+2*qx , cy+2*qy ); grid_face_set_dot(g, d, 4);
1339 grid_face_add_new(g, 5);
1340 d = grid_get_dot(g, points, cx , cy ); grid_face_set_dot(g, d, 0);
1341 d = grid_get_dot(g, points, cx+2*qx , cy+2*qy ); grid_face_set_dot(g, d, 1);
1342 d = grid_get_dot(g, points, cx+2*qx+px, cy+2*qy+py); grid_face_set_dot(g, d, 2);
1343 d = grid_get_dot(g, points, cx+2*px+qx, cy+2*py+qy); grid_face_set_dot(g, d, 3);
1344 d = grid_get_dot(g, points, cx+2*px , cy+2*py ); grid_face_set_dot(g, d, 4);
1346 grid_face_add_new(g, 5);
1347 d = grid_get_dot(g, points, cx , cy ); grid_face_set_dot(g, d, 0);
1348 d = grid_get_dot(g, points, cx+2*px , cy+2*py ); grid_face_set_dot(g, d, 1);
1349 d = grid_get_dot(g, points, cx+2*px-rx, cy+2*py-ry); grid_face_set_dot(g, d, 2);
1350 d = grid_get_dot(g, points, cx-2*rx+px, cy-2*ry+py); grid_face_set_dot(g, d, 3);
1351 d = grid_get_dot(g, points, cx-2*rx , cy-2*ry ); grid_face_set_dot(g, d, 4);
1353 grid_face_add_new(g, 5);
1354 d = grid_get_dot(g, points, cx , cy ); grid_face_set_dot(g, d, 0);
1355 d = grid_get_dot(g, points, cx-2*rx , cy-2*ry ); grid_face_set_dot(g, d, 1);
1356 d = grid_get_dot(g, points, cx-2*rx-qx, cy-2*ry-qy); grid_face_set_dot(g, d, 2);
1357 d = grid_get_dot(g, points, cx-2*qx-rx, cy-2*qy-ry); grid_face_set_dot(g, d, 3);
1358 d = grid_get_dot(g, points, cx-2*qx , cy-2*qy ); grid_face_set_dot(g, d, 4);
1360 grid_face_add_new(g, 5);
1361 d = grid_get_dot(g, points, cx , cy ); grid_face_set_dot(g, d, 0);
1362 d = grid_get_dot(g, points, cx-2*qx , cy-2*qy ); grid_face_set_dot(g, d, 1);
1363 d = grid_get_dot(g, points, cx-2*qx-px, cy-2*qy-py); grid_face_set_dot(g, d, 2);
1364 d = grid_get_dot(g, points, cx-2*px-qx, cy-2*py-qy); grid_face_set_dot(g, d, 3);
1365 d = grid_get_dot(g, points, cx-2*px , cy-2*py ); grid_face_set_dot(g, d, 4);
1367 grid_face_add_new(g, 5);
1368 d = grid_get_dot(g, points, cx , cy ); grid_face_set_dot(g, d, 0);
1369 d = grid_get_dot(g, points, cx-2*px , cy-2*py ); grid_face_set_dot(g, d, 1);
1370 d = grid_get_dot(g, points, cx-2*px+rx, cy-2*py+ry); grid_face_set_dot(g, d, 2);
1371 d = grid_get_dot(g, points, cx+2*rx-px, cy+2*ry-py); grid_face_set_dot(g, d, 3);
1372 d = grid_get_dot(g, points, cx+2*rx , cy+2*ry ); grid_face_set_dot(g, d, 4);
1376 freetree234(points);
1377 assert(g->num_faces <= max_faces);
1378 assert(g->num_dots <= max_dots);
1380 grid_make_consistent(g);
1384 /* ----------- End of grid generators ------------- */