X-Git-Url: http://www.chiark.greenend.org.uk/ucgi/~ian/git?a=blobdiff_plain;f=grid.c;h=6a90c9942e3a44edff78696e9c6ffd00e554cdce;hb=3ce69e84cad15844282d691fa03e711c5353c05e;hp=1415e61f067a7b520b40f5f30826bef278400c25;hpb=1a628aebd8893001bc3a2e9dbc3e2dc7432b08e4;p=sgt-puzzles.git diff --git a/grid.c b/grid.c index 1415e61..6a90c99 100644 --- a/grid.c +++ b/grid.c @@ -12,10 +12,12 @@ #include #include #include +#include #include "puzzles.h" #include "tree234.h" #include "grid.h" +#include "penrose.h" /* Debugging options */ @@ -50,14 +52,13 @@ void grid_free(grid *g) /* Used by the other grid generators. Create a brand new grid with nothing * initialised (all lists are NULL) */ -static grid *grid_new(void) +static grid *grid_empty(void) { grid *g = snew(grid); g->faces = NULL; g->edges = NULL; g->dots = NULL; g->num_faces = g->num_edges = g->num_dots = 0; - g->middle_face = NULL; g->refcount = 1; g->lowest_x = g->lowest_y = g->highest_x = g->highest_y = 0; return g; @@ -92,17 +93,9 @@ static double point_line_distance(long px, long py, * Returns the nearest edge, or NULL if no edge is reasonably * near the position. * - * This algorithm is nice and generic, and doesn't depend on any particular - * geometric layout of the grid: - * Start at any dot (pick one next to middle_face). - * Walk along a path by choosing, from all nearby dots, the one that is - * nearest the target (x,y). Hopefully end up at the dot which is closest - * to (x,y). Should work, as long as faces aren't too badly shaped. - * Then examine each edge around this dot, and pick whichever one is - * closest (perpendicular distance) to (x,y). - * Using perpendicular distance is not quite right - the edge might be - * "off to one side". So we insist that the triangle with (x,y) has - * acute angles at the edge's dots. + * Just judging edges by perpendicular distance is not quite right - + * the edge might be "off to one side". So we insist that the triangle + * with (x,y) has acute angles at the edge's dots. * * edge1 * *---------*------ @@ -116,50 +109,14 @@ static double point_line_distance(long px, long py, */ grid_edge *grid_nearest_edge(grid *g, int x, int y) { - grid_dot *cur; grid_edge *best_edge; double best_distance = 0; int i; - cur = g->middle_face->dots[0]; - - for (;;) { - /* Target to beat */ - long dist = SQ((long)cur->x - (long)x) + SQ((long)cur->y - (long)y); - /* Look for nearer dot - if found, store in 'new'. */ - grid_dot *new = cur; - int i; - /* Search all dots in all faces touching this dot. Some shapes - * (such as in Cairo) don't quite work properly if we only search - * the dot's immediate neighbours. */ - for (i = 0; i < cur->order; i++) { - grid_face *f = cur->faces[i]; - int j; - if (!f) continue; - for (j = 0; j < f->order; j++) { - long new_dist; - grid_dot *d = f->dots[j]; - if (d == cur) continue; - new_dist = SQ((long)d->x - (long)x) + SQ((long)d->y - (long)y); - if (new_dist < dist) { /* found closer dot */ - new = d; - dist = new_dist; - } - } - } - - if (new == cur) { - /* Didn't find a closer dot among the neighbours of 'cur' */ - break; - } else { - cur = new; - } - } - /* 'cur' is nearest dot, so find which of the dot's edges is closest. */ best_edge = NULL; - for (i = 0; i < cur->order; i++) { - grid_edge *e = cur->edges[i]; + for (i = 0; i < g->num_edges; i++) { + grid_edge *e = &g->edges[i]; long e2; /* squared length of edge */ long a2, b2; /* squared lengths of other sides */ double dist; @@ -203,13 +160,95 @@ grid_edge *grid_nearest_edge(grid *g, int x, int y) * Grid generation */ -#ifdef DEBUG_GRID +#ifdef SVG_GRID + +#define SVG_DOTS 1 +#define SVG_EDGES 2 +#define SVG_FACES 4 + +#define FACE_COLOUR "red" +#define EDGE_COLOUR "blue" +#define DOT_COLOUR "black" + +static void grid_output_svg(FILE *fp, grid *g, int which) +{ + int i, j; + + fprintf(fp,"\ +\n\ +\n\ +\n\ +\n\n"); + + if (which & SVG_FACES) { + fprintf(fp, "\n"); + for (i = 0; i < g->num_faces; i++) { + grid_face *f = g->faces + i; + fprintf(fp, "order; j++) { + grid_dot *d = f->dots[j]; + fprintf(fp, "%s%d,%d", (j == 0) ? "" : " ", + d->x, d->y); + } + fprintf(fp, "\" style=\"fill: %s; fill-opacity: 0.2; stroke: %s\" />\n", + FACE_COLOUR, FACE_COLOUR); + } + fprintf(fp, "\n"); + } + if (which & SVG_EDGES) { + fprintf(fp, "\n"); + for (i = 0; i < g->num_edges; i++) { + grid_edge *e = g->edges + i; + grid_dot *d1 = e->dot1, *d2 = e->dot2; + + fprintf(fp, "\n", + d1->x, d1->y, d2->x, d2->y, EDGE_COLOUR); + } + fprintf(fp, "\n"); + } + + if (which & SVG_DOTS) { + fprintf(fp, "\n"); + for (i = 0; i < g->num_dots; i++) { + grid_dot *d = g->dots + i; + fprintf(fp, "", + d->x, d->y, g->tilesize/20, g->tilesize/20, DOT_COLOUR); + } + fprintf(fp, "\n"); + } + + fprintf(fp, "\n"); +} +#endif + +#ifdef SVG_GRID +#include + +static void grid_try_svg(grid *g, int which) +{ + char *svg = getenv("PUZZLES_SVG_GRID"); + if (svg) { + FILE *svgf = fopen(svg, "w"); + if (svgf) { + grid_output_svg(svgf, g, which); + fclose(svgf); + } else { + fprintf(stderr, "Unable to open file `%s': %s", svg, strerror(errno)); + } + } +} +#endif + /* Show the basic grid information, before doing grid_make_consistent */ -static void grid_print_basic(grid *g) +static void grid_debug_basic(grid *g) { /* TODO: Maybe we should generate an SVG image of the dots and lines * of the grid here, before grid_make_consistent. * Would help with debugging grid generation. */ +#ifdef DEBUG_GRID int i; printf("--- Basic Grid Data ---\n"); for (i = 0; i < g->num_faces; i++) { @@ -222,11 +261,16 @@ static void grid_print_basic(grid *g) } printf("]\n"); } - printf("Middle face: %d\n", (int)(g->middle_face - g->faces)); +#endif +#ifdef SVG_GRID + grid_try_svg(g, SVG_FACES); +#endif } + /* Show the derived grid information, computed by grid_make_consistent */ -static void grid_print_derived(grid *g) +static void grid_debug_derived(grid *g) { +#ifdef DEBUG_GRID /* edges */ int i; printf("--- Derived Grid Data ---\n"); @@ -266,8 +310,11 @@ static void grid_print_derived(grid *g) } printf("]\n"); } +#endif +#ifdef SVG_GRID + grid_try_svg(g, SVG_DOTS | SVG_EDGES | SVG_FACES); +#endif } -#endif /* DEBUG_GRID */ /* Helper function for building incomplete-edges list in * grid_make_consistent() */ @@ -296,6 +343,155 @@ static int grid_edge_bydots_cmpfn(void *v1, void *v2) return 0; } +/* + * 'Vigorously trim' a grid, by which I mean deleting any isolated or + * uninteresting faces. By which, in turn, I mean: ensure that the + * grid is composed solely of faces adjacent to at least one + * 'landlocked' dot (i.e. one not in contact with the infinite + * exterior face), and that all those dots are in a single connected + * component. + * + * This function operates on, and returns, a grid satisfying the + * preconditions to grid_make_consistent() rather than the + * postconditions. (So call it first.) + */ +static void grid_trim_vigorously(grid *g) +{ + int *dotpairs, *faces, *dots; + int *dsf; + int i, j, k, size, newfaces, newdots; + + /* + * First construct a matrix in which each ordered pair of dots is + * mapped to the index of the face in which those dots occur in + * that order. + */ + dotpairs = snewn(g->num_dots * g->num_dots, int); + for (i = 0; i < g->num_dots; i++) + for (j = 0; j < g->num_dots; j++) + dotpairs[i*g->num_dots+j] = -1; + for (i = 0; i < g->num_faces; i++) { + grid_face *f = g->faces + i; + int dot0 = f->dots[f->order-1] - g->dots; + for (j = 0; j < f->order; j++) { + int dot1 = f->dots[j] - g->dots; + dotpairs[dot0 * g->num_dots + dot1] = i; + dot0 = dot1; + } + } + + /* + * Now we can identify landlocked dots: they're the ones all of + * whose edges have a mirror-image counterpart in this matrix. + */ + dots = snewn(g->num_dots, int); + for (i = 0; i < g->num_dots; i++) { + dots[i] = TRUE; + for (j = 0; j < g->num_dots; j++) { + if ((dotpairs[i*g->num_dots+j] >= 0) ^ + (dotpairs[j*g->num_dots+i] >= 0)) + dots[i] = FALSE; /* non-duplicated edge: coastal dot */ + } + } + + /* + * Now identify connected pairs of landlocked dots, and form a dsf + * unifying them. + */ + dsf = snew_dsf(g->num_dots); + for (i = 0; i < g->num_dots; i++) + for (j = 0; j < i; j++) + if (dots[i] && dots[j] && + dotpairs[i*g->num_dots+j] >= 0 && + dotpairs[j*g->num_dots+i] >= 0) + dsf_merge(dsf, i, j); + + /* + * Now look for the largest component. + */ + size = 0; + j = -1; + for (i = 0; i < g->num_dots; i++) { + int newsize; + if (dots[i] && dsf_canonify(dsf, i) == i && + (newsize = dsf_size(dsf, i)) > size) { + j = i; + size = newsize; + } + } + + /* + * Work out which faces we're going to keep (precisely those with + * at least one dot in the same connected component as j) and + * which dots (those required by any face we're keeping). + * + * At this point we reuse the 'dots' array to indicate the dots + * we're keeping, rather than the ones that are landlocked. + */ + faces = snewn(g->num_faces, int); + for (i = 0; i < g->num_faces; i++) + faces[i] = 0; + for (i = 0; i < g->num_dots; i++) + dots[i] = 0; + for (i = 0; i < g->num_faces; i++) { + grid_face *f = g->faces + i; + int keep = FALSE; + for (k = 0; k < f->order; k++) + if (dsf_canonify(dsf, f->dots[k] - g->dots) == j) + keep = TRUE; + if (keep) { + faces[i] = TRUE; + for (k = 0; k < f->order; k++) + dots[f->dots[k]-g->dots] = TRUE; + } + } + + /* + * Work out the new indices of those faces and dots, when we + * compact the arrays containing them. + */ + for (i = newfaces = 0; i < g->num_faces; i++) + faces[i] = (faces[i] ? newfaces++ : -1); + for (i = newdots = 0; i < g->num_dots; i++) + dots[i] = (dots[i] ? newdots++ : -1); + + /* + * Free the dynamically allocated 'dots' pointer lists in faces + * we're going to discard. + */ + for (i = 0; i < g->num_faces; i++) + if (faces[i] < 0) + sfree(g->faces[i].dots); + + /* + * Go through and compact the arrays. + */ + for (i = 0; i < g->num_dots; i++) + if (dots[i] >= 0) { + grid_dot *dnew = g->dots + dots[i], *dold = g->dots + i; + *dnew = *dold; /* structure copy */ + } + for (i = 0; i < g->num_faces; i++) + if (faces[i] >= 0) { + grid_face *fnew = g->faces + faces[i], *fold = g->faces + i; + *fnew = *fold; /* structure copy */ + for (j = 0; j < fnew->order; j++) { + /* + * Reindex the dots in this face. + */ + k = fnew->dots[j] - g->dots; + fnew->dots[j] = g->dots + dots[k]; + } + } + g->num_faces = newfaces; + g->num_dots = newdots; + + sfree(dotpairs); + sfree(dsf); + sfree(dots); + sfree(faces); +} + /* Input: grid has its dots and faces initialised: * - dots have (optionally) x and y coordinates, but no edges or faces * (pointers are NULL). @@ -311,9 +507,7 @@ static void grid_make_consistent(grid *g) tree234 *incomplete_edges; grid_edge *next_new_edge; /* Where new edge will go into g->edges */ -#ifdef DEBUG_GRID - grid_print_basic(g); -#endif + grid_debug_basic(g); /* ====== Stage 1 ====== * Generate edges @@ -591,10 +785,8 @@ static void grid_make_consistent(grid *g) g->highest_y = max(g->highest_y, d->y); } } - -#ifdef DEBUG_GRID - grid_print_derived(g); -#endif + + grid_debug_derived(g); } /* Helpers for making grid-generation easier. These functions are only @@ -621,6 +813,7 @@ static void grid_face_add_new(grid *g, int face_size) for (i = 0; i < face_size; i++) new_face->dots[i] = NULL; new_face->edges = NULL; + new_face->has_incentre = FALSE; g->num_faces++; } /* Assumes dot list has enough space */ @@ -666,6 +859,516 @@ static void grid_face_set_dot(grid *g, grid_dot *d, int position) last_face->dots[position] = d; } +/* + * Helper routines for grid_find_incentre. + */ +static int solve_2x2_matrix(double mx[4], double vin[2], double vout[2]) +{ + double inv[4]; + double det; + det = (mx[0]*mx[3] - mx[1]*mx[2]); + if (det == 0) + return FALSE; + + inv[0] = mx[3] / det; + inv[1] = -mx[1] / det; + inv[2] = -mx[2] / det; + inv[3] = mx[0] / det; + + vout[0] = inv[0]*vin[0] + inv[1]*vin[1]; + vout[1] = inv[2]*vin[0] + inv[3]*vin[1]; + + return TRUE; +} +static int solve_3x3_matrix(double mx[9], double vin[3], double vout[3]) +{ + double inv[9]; + double det; + + det = (mx[0]*mx[4]*mx[8] + mx[1]*mx[5]*mx[6] + mx[2]*mx[3]*mx[7] - + mx[0]*mx[5]*mx[7] - mx[1]*mx[3]*mx[8] - mx[2]*mx[4]*mx[6]); + if (det == 0) + return FALSE; + + inv[0] = (mx[4]*mx[8] - mx[5]*mx[7]) / det; + inv[1] = (mx[2]*mx[7] - mx[1]*mx[8]) / det; + inv[2] = (mx[1]*mx[5] - mx[2]*mx[4]) / det; + inv[3] = (mx[5]*mx[6] - mx[3]*mx[8]) / det; + inv[4] = (mx[0]*mx[8] - mx[2]*mx[6]) / det; + inv[5] = (mx[2]*mx[3] - mx[0]*mx[5]) / det; + inv[6] = (mx[3]*mx[7] - mx[4]*mx[6]) / det; + inv[7] = (mx[1]*mx[6] - mx[0]*mx[7]) / det; + inv[8] = (mx[0]*mx[4] - mx[1]*mx[3]) / det; + + vout[0] = inv[0]*vin[0] + inv[1]*vin[1] + inv[2]*vin[2]; + vout[1] = inv[3]*vin[0] + inv[4]*vin[1] + inv[5]*vin[2]; + vout[2] = inv[6]*vin[0] + inv[7]*vin[1] + inv[8]*vin[2]; + + return TRUE; +} + +void grid_find_incentre(grid_face *f) +{ + double xbest, ybest, bestdist; + int i, j, k, m; + grid_dot *edgedot1[3], *edgedot2[3]; + grid_dot *dots[3]; + int nedges, ndots; + + if (f->has_incentre) + return; + + /* + * Find the point in the polygon with the maximum distance to any + * edge or corner. + * + * Such a point must exist which is in contact with at least three + * edges and/or vertices. (Proof: if it's only in contact with two + * edges and/or vertices, it can't even be at a _local_ maximum - + * any such circle can always be expanded in some direction.) So + * we iterate through all 3-subsets of the combined set of edges + * and vertices; for each subset we generate one or two candidate + * points that might be the incentre, and then we vet each one to + * see if it's inside the polygon and what its maximum radius is. + * + * (There's one case which this algorithm will get noticeably + * wrong, and that's when a continuum of equally good answers + * exists due to parallel edges. Consider a long thin rectangle, + * for instance, or a parallelogram. This algorithm will pick a + * point near one end, and choose the end arbitrarily; obviously a + * nicer point to choose would be in the centre. To fix this I + * would have to introduce a special-case system which detected + * parallel edges in advance, set aside all candidate points + * generated using both edges in a parallel pair, and generated + * some additional candidate points half way between them. Also, + * of course, I'd have to cope with rounding error making such a + * point look worse than one of its endpoints. So I haven't done + * this for the moment, and will cross it if necessary when I come + * to it.) + * + * We don't actually iterate literally over _edges_, in the sense + * of grid_edge structures. Instead, we fill in edgedot1[] and + * edgedot2[] with a pair of dots adjacent in the face's list of + * vertices. This ensures that we get the edges in consistent + * orientation, which we could not do from the grid structure + * alone. (A moment's consideration of an order-3 vertex should + * make it clear that if a notional arrow was written on each + * edge, _at least one_ of the three faces bordering that vertex + * would have to have the two arrows tip-to-tip or tail-to-tail + * rather than tip-to-tail.) + */ + nedges = ndots = 0; + bestdist = 0; + xbest = ybest = 0; + + for (i = 0; i+2 < 2*f->order; i++) { + if (i < f->order) { + edgedot1[nedges] = f->dots[i]; + edgedot2[nedges++] = f->dots[(i+1)%f->order]; + } else + dots[ndots++] = f->dots[i - f->order]; + + for (j = i+1; j+1 < 2*f->order; j++) { + if (j < f->order) { + edgedot1[nedges] = f->dots[j]; + edgedot2[nedges++] = f->dots[(j+1)%f->order]; + } else + dots[ndots++] = f->dots[j - f->order]; + + for (k = j+1; k < 2*f->order; k++) { + double cx[2], cy[2]; /* candidate positions */ + int cn = 0; /* number of candidates */ + + if (k < f->order) { + edgedot1[nedges] = f->dots[k]; + edgedot2[nedges++] = f->dots[(k+1)%f->order]; + } else + dots[ndots++] = f->dots[k - f->order]; + + /* + * Find a point, or pair of points, equidistant from + * all the specified edges and/or vertices. + */ + if (nedges == 3) { + /* + * Three edges. This is a linear matrix equation: + * each row of the matrix represents the fact that + * the point (x,y) we seek is at distance r from + * that edge, and we solve three of those + * simultaneously to obtain x,y,r. (We ignore r.) + */ + double matrix[9], vector[3], vector2[3]; + int m; + + for (m = 0; m < 3; m++) { + int x1 = edgedot1[m]->x, x2 = edgedot2[m]->x; + int y1 = edgedot1[m]->y, y2 = edgedot2[m]->y; + int dx = x2-x1, dy = y2-y1; + + /* + * ((x,y) - (x1,y1)) . (dy,-dx) = r |(dx,dy)| + * + * => x dy - y dx - r |(dx,dy)| = (x1 dy - y1 dx) + */ + matrix[3*m+0] = dy; + matrix[3*m+1] = -dx; + matrix[3*m+2] = -sqrt((double)dx*dx+(double)dy*dy); + vector[m] = (double)x1*dy - (double)y1*dx; + } + + if (solve_3x3_matrix(matrix, vector, vector2)) { + cx[cn] = vector2[0]; + cy[cn] = vector2[1]; + cn++; + } + } else if (nedges == 2) { + /* + * Two edges and a dot. This will end up in a + * quadratic equation. + * + * First, look at the two edges. Having our point + * be some distance r from both of them gives rise + * to a pair of linear equations in x,y,r of the + * form + * + * (x-x1) dy - (y-y1) dx = r sqrt(dx^2+dy^2) + * + * We eliminate r between those equations to give + * us a single linear equation in x,y describing + * the locus of points equidistant from both lines + * - i.e. the angle bisector. + * + * We then choose one of x,y to be a parameter t, + * and derive linear formulae for x,y,r in terms + * of t. This enables us to write down the + * circular equation (x-xd)^2+(y-yd)^2=r^2 as a + * quadratic in t; solving that and substituting + * in for x,y gives us two candidate points. + */ + double eqs[2][4]; /* a,b,c,d : ax+by+cr=d */ + double eq[3]; /* a,b,c: ax+by=c */ + double xt[2], yt[2], rt[2]; /* a,b: {x,y,r}=at+b */ + double q[3]; /* a,b,c: at^2+bt+c=0 */ + double disc; + + /* Find equations of the two input lines. */ + for (m = 0; m < 2; m++) { + int x1 = edgedot1[m]->x, x2 = edgedot2[m]->x; + int y1 = edgedot1[m]->y, y2 = edgedot2[m]->y; + int dx = x2-x1, dy = y2-y1; + + eqs[m][0] = dy; + eqs[m][1] = -dx; + eqs[m][2] = -sqrt(dx*dx+dy*dy); + eqs[m][3] = x1*dy - y1*dx; + } + + /* Derive the angle bisector by eliminating r. */ + eq[0] = eqs[0][0]*eqs[1][2] - eqs[1][0]*eqs[0][2]; + eq[1] = eqs[0][1]*eqs[1][2] - eqs[1][1]*eqs[0][2]; + eq[2] = eqs[0][3]*eqs[1][2] - eqs[1][3]*eqs[0][2]; + + /* Parametrise x and y in terms of some t. */ + if (fabs(eq[0]) < fabs(eq[1])) { + /* Parameter is x. */ + xt[0] = 1; xt[1] = 0; + yt[0] = -eq[0]/eq[1]; yt[1] = eq[2]/eq[1]; + } else { + /* Parameter is y. */ + yt[0] = 1; yt[1] = 0; + xt[0] = -eq[1]/eq[0]; xt[1] = eq[2]/eq[0]; + } + + /* Find a linear representation of r using eqs[0]. */ + rt[0] = -(eqs[0][0]*xt[0] + eqs[0][1]*yt[0])/eqs[0][2]; + rt[1] = (eqs[0][3] - eqs[0][0]*xt[1] - + eqs[0][1]*yt[1])/eqs[0][2]; + + /* Construct the quadratic equation. */ + q[0] = -rt[0]*rt[0]; + q[1] = -2*rt[0]*rt[1]; + q[2] = -rt[1]*rt[1]; + q[0] += xt[0]*xt[0]; + q[1] += 2*xt[0]*(xt[1]-dots[0]->x); + q[2] += (xt[1]-dots[0]->x)*(xt[1]-dots[0]->x); + q[0] += yt[0]*yt[0]; + q[1] += 2*yt[0]*(yt[1]-dots[0]->y); + q[2] += (yt[1]-dots[0]->y)*(yt[1]-dots[0]->y); + + /* And solve it. */ + disc = q[1]*q[1] - 4*q[0]*q[2]; + if (disc >= 0) { + double t; + + disc = sqrt(disc); + + t = (-q[1] + disc) / (2*q[0]); + cx[cn] = xt[0]*t + xt[1]; + cy[cn] = yt[0]*t + yt[1]; + cn++; + + t = (-q[1] - disc) / (2*q[0]); + cx[cn] = xt[0]*t + xt[1]; + cy[cn] = yt[0]*t + yt[1]; + cn++; + } + } else if (nedges == 1) { + /* + * Two dots and an edge. This one's another + * quadratic equation. + * + * The point we want must lie on the perpendicular + * bisector of the two dots; that much is obvious. + * So we can construct a parametrisation of that + * bisecting line, giving linear formulae for x,y + * in terms of t. We can also express the distance + * from the edge as such a linear formula. + * + * Then we set that equal to the radius of the + * circle passing through the two points, which is + * a Pythagoras exercise; that gives rise to a + * quadratic in t, which we solve. + */ + double xt[2], yt[2], rt[2]; /* a,b: {x,y,r}=at+b */ + double q[3]; /* a,b,c: at^2+bt+c=0 */ + double disc; + double halfsep; + + /* Find parametric formulae for x,y. */ + { + int x1 = dots[0]->x, x2 = dots[1]->x; + int y1 = dots[0]->y, y2 = dots[1]->y; + int dx = x2-x1, dy = y2-y1; + double d = sqrt((double)dx*dx + (double)dy*dy); + + xt[1] = (x1+x2)/2.0; + yt[1] = (y1+y2)/2.0; + /* It's convenient if we have t at standard scale. */ + xt[0] = -dy/d; + yt[0] = dx/d; + + /* Also note down half the separation between + * the dots, for use in computing the circle radius. */ + halfsep = 0.5*d; + } + + /* Find a parametric formula for r. */ + { + int x1 = edgedot1[0]->x, x2 = edgedot2[0]->x; + int y1 = edgedot1[0]->y, y2 = edgedot2[0]->y; + int dx = x2-x1, dy = y2-y1; + double d = sqrt((double)dx*dx + (double)dy*dy); + rt[0] = (xt[0]*dy - yt[0]*dx) / d; + rt[1] = ((xt[1]-x1)*dy - (yt[1]-y1)*dx) / d; + } + + /* Construct the quadratic equation. */ + q[0] = rt[0]*rt[0]; + q[1] = 2*rt[0]*rt[1]; + q[2] = rt[1]*rt[1]; + q[0] -= 1; + q[2] -= halfsep*halfsep; + + /* And solve it. */ + disc = q[1]*q[1] - 4*q[0]*q[2]; + if (disc >= 0) { + double t; + + disc = sqrt(disc); + + t = (-q[1] + disc) / (2*q[0]); + cx[cn] = xt[0]*t + xt[1]; + cy[cn] = yt[0]*t + yt[1]; + cn++; + + t = (-q[1] - disc) / (2*q[0]); + cx[cn] = xt[0]*t + xt[1]; + cy[cn] = yt[0]*t + yt[1]; + cn++; + } + } else if (nedges == 0) { + /* + * Three dots. This is another linear matrix + * equation, this time with each row of the matrix + * representing the perpendicular bisector between + * two of the points. Of course we only need two + * such lines to find their intersection, so we + * need only solve a 2x2 matrix equation. + */ + + double matrix[4], vector[2], vector2[2]; + int m; + + for (m = 0; m < 2; m++) { + int x1 = dots[m]->x, x2 = dots[m+1]->x; + int y1 = dots[m]->y, y2 = dots[m+1]->y; + int dx = x2-x1, dy = y2-y1; + + /* + * ((x,y) - (x1,y1)) . (dx,dy) = 1/2 |(dx,dy)|^2 + * + * => 2x dx + 2y dy = dx^2+dy^2 + (2 x1 dx + 2 y1 dy) + */ + matrix[2*m+0] = 2*dx; + matrix[2*m+1] = 2*dy; + vector[m] = ((double)dx*dx + (double)dy*dy + + 2.0*x1*dx + 2.0*y1*dy); + } + + if (solve_2x2_matrix(matrix, vector, vector2)) { + cx[cn] = vector2[0]; + cy[cn] = vector2[1]; + cn++; + } + } + + /* + * Now go through our candidate points and see if any + * of them are better than what we've got so far. + */ + for (m = 0; m < cn; m++) { + double x = cx[m], y = cy[m]; + + /* + * First, disqualify the point if it's not inside + * the polygon, which we work out by counting the + * edges to the right of the point. (For + * tiebreaking purposes when edges start or end on + * our y-coordinate or go right through it, we + * consider our point to be offset by a small + * _positive_ epsilon in both the x- and + * y-direction.) + */ + int e, in = 0; + for (e = 0; e < f->order; e++) { + int xs = f->edges[e]->dot1->x; + int xe = f->edges[e]->dot2->x; + int ys = f->edges[e]->dot1->y; + int ye = f->edges[e]->dot2->y; + if ((y >= ys && y < ye) || (y >= ye && y < ys)) { + /* + * The line goes past our y-position. Now we need + * to know if its x-coordinate when it does so is + * to our right. + * + * The x-coordinate in question is mathematically + * (y - ys) * (xe - xs) / (ye - ys), and we want + * to know whether (x - xs) >= that. Of course we + * avoid the division, so we can work in integers; + * to do this we must multiply both sides of the + * inequality by ye - ys, which means we must + * first check that's not negative. + */ + int num = xe - xs, denom = ye - ys; + if (denom < 0) { + num = -num; + denom = -denom; + } + if ((x - xs) * denom >= (y - ys) * num) + in ^= 1; + } + } + + if (in) { +#ifdef HUGE_VAL + double mindist = HUGE_VAL; +#else +#ifdef DBL_MAX + double mindist = DBL_MAX; +#else +#error No way to get maximum floating-point number. +#endif +#endif + int e, d; + + /* + * This point is inside the polygon, so now we check + * its minimum distance to every edge and corner. + * First the corners ... + */ + for (d = 0; d < f->order; d++) { + int xp = f->dots[d]->x; + int yp = f->dots[d]->y; + double dx = x - xp, dy = y - yp; + double dist = dx*dx + dy*dy; + if (mindist > dist) + mindist = dist; + } + + /* + * ... and now also check the perpendicular distance + * to every edge, if the perpendicular lies between + * the edge's endpoints. + */ + for (e = 0; e < f->order; e++) { + int xs = f->edges[e]->dot1->x; + int xe = f->edges[e]->dot2->x; + int ys = f->edges[e]->dot1->y; + int ye = f->edges[e]->dot2->y; + + /* + * If s and e are our endpoints, and p our + * candidate circle centre, the foot of a + * perpendicular from p to the line se lies + * between s and e if and only if (p-s).(e-s) lies + * strictly between 0 and (e-s).(e-s). + */ + int edx = xe - xs, edy = ye - ys; + double pdx = x - xs, pdy = y - ys; + double pde = pdx * edx + pdy * edy; + long ede = (long)edx * edx + (long)edy * edy; + if (0 < pde && pde < ede) { + /* + * Yes, the nearest point on this edge is + * closer than either endpoint, so we must + * take it into account by measuring the + * perpendicular distance to the edge and + * checking its square against mindist. + */ + + double pdre = pdx * edy - pdy * edx; + double sqlen = pdre * pdre / ede; + + if (mindist > sqlen) + mindist = sqlen; + } + } + + /* + * Right. Now we know the biggest circle around this + * point, so we can check it against bestdist. + */ + if (bestdist < mindist) { + bestdist = mindist; + xbest = x; + ybest = y; + } + } + } + + if (k < f->order) + nedges--; + else + ndots--; + } + if (j < f->order) + nedges--; + else + ndots--; + } + if (i < f->order) + nedges--; + else + ndots--; + } + + assert(bestdist > 0); + + f->has_incentre = TRUE; + f->ix = xbest + 0.5; /* round to nearest */ + f->iy = ybest + 0.5; +} + /* ------ Generate various types of grid ------ */ /* General method is to generate faces, by calculating their dot coordinates. @@ -682,11 +1385,23 @@ static void grid_face_set_dot(grid *g, grid_dot *d, int position) * arithmetic here! */ -grid *grid_new_square(int width, int height) +#define SQUARE_TILESIZE 20 + +static void grid_size_square(int width, int height, + int *tilesize, int *xextent, int *yextent) +{ + int a = SQUARE_TILESIZE; + + *tilesize = a; + *xextent = width * a; + *yextent = height * a; +} + +static grid *grid_new_square(int width, int height, const char *desc) { int x, y; /* Side length */ - int a = 20; + int a = SQUARE_TILESIZE; /* Upper bounds - don't have to be exact */ int max_faces = width * height; @@ -694,7 +1409,7 @@ grid *grid_new_square(int width, int height) tree234 *points; - grid *g = grid_new(); + grid *g = grid_empty(); g->tilesize = a; g->faces = snewn(max_faces, grid_face); g->dots = snewn(max_dots, grid_dot); @@ -724,27 +1439,41 @@ grid *grid_new_square(int width, int height) freetree234(points); assert(g->num_faces <= max_faces); assert(g->num_dots <= max_dots); - g->middle_face = g->faces + (height/2) * width + (width/2); grid_make_consistent(g); return g; } -grid *grid_new_honeycomb(int width, int height) +#define HONEY_TILESIZE 45 +/* Vector for side of hexagon - ratio is close to sqrt(3) */ +#define HONEY_A 15 +#define HONEY_B 26 + +static void grid_size_honeycomb(int width, int height, + int *tilesize, int *xextent, int *yextent) +{ + int a = HONEY_A; + int b = HONEY_B; + + *tilesize = HONEY_TILESIZE; + *xextent = (3 * a * (width-1)) + 4*a; + *yextent = (2 * b * (height-1)) + 3*b; +} + +static grid *grid_new_honeycomb(int width, int height, const char *desc) { int x, y; - /* Vector for side of hexagon - ratio is close to sqrt(3) */ - int a = 15; - int b = 26; + int a = HONEY_A; + int b = HONEY_B; /* Upper bounds - don't have to be exact */ int max_faces = width * height; int max_dots = 2 * (width + 1) * (height + 1); - + tree234 *points; - grid *g = grid_new(); - g->tilesize = 3 * a; + grid *g = grid_empty(); + g->tilesize = HONEY_TILESIZE; g->faces = snewn(max_faces, grid_face); g->dots = snewn(max_dots, grid_dot); @@ -779,108 +1508,238 @@ grid *grid_new_honeycomb(int width, int height) freetree234(points); assert(g->num_faces <= max_faces); assert(g->num_dots <= max_dots); - g->middle_face = g->faces + (height/2) * width + (width/2); grid_make_consistent(g); return g; } +#define TRIANGLE_TILESIZE 18 +/* Vector for side of triangle - ratio is close to sqrt(3) */ +#define TRIANGLE_VEC_X 15 +#define TRIANGLE_VEC_Y 26 + +static void grid_size_triangular(int width, int height, + int *tilesize, int *xextent, int *yextent) +{ + int vec_x = TRIANGLE_VEC_X; + int vec_y = TRIANGLE_VEC_Y; + + *tilesize = TRIANGLE_TILESIZE; + *xextent = (width+1) * 2 * vec_x; + *yextent = height * vec_y; +} + +static char *grid_validate_desc_triangular(grid_type type, int width, + int height, const char *desc) +{ + /* + * Triangular grids: an absent description is valid (indicating + * the old-style approach which had 'ears', i.e. triangles + * connected to only one other face, at some grid corners), and so + * is a description reading just "0" (indicating the new-style + * approach in which those ears are trimmed off). Anything else is + * illegal. + */ + + if (!desc || !strcmp(desc, "0")) + return NULL; + + return "Unrecognised grid description."; +} + /* Doesn't use the previous method of generation, it pre-dates it! * A triangular grid is just about simple enough to do by "brute force" */ -grid *grid_new_triangular(int width, int height) +static grid *grid_new_triangular(int width, int height, const char *desc) { int x,y; + int version = (desc == NULL ? -1 : atoi(desc)); /* Vector for side of triangle - ratio is close to sqrt(3) */ - int vec_x = 15; - int vec_y = 26; + int vec_x = TRIANGLE_VEC_X; + int vec_y = TRIANGLE_VEC_Y; int index; /* convenient alias */ int w = width + 1; - grid *g = grid_new(); - g->tilesize = 18; /* adjust to your taste */ - - g->num_faces = width * height * 2; - g->num_dots = (width + 1) * (height + 1); - g->faces = snewn(g->num_faces, grid_face); - g->dots = snewn(g->num_dots, grid_dot); - - /* generate dots */ - index = 0; - for (y = 0; y <= height; y++) { - for (x = 0; x <= width; x++) { - grid_dot *d = g->dots + index; - /* odd rows are offset to the right */ - d->order = 0; - d->edges = NULL; - d->faces = NULL; - d->x = x * 2 * vec_x + ((y % 2) ? vec_x : 0); - d->y = y * vec_y; - index++; + grid *g = grid_empty(); + g->tilesize = TRIANGLE_TILESIZE; + + if (version == -1) { + /* + * Old-style triangular grid generation, preserved as-is for + * backwards compatibility with old game ids, in which it's + * just a little asymmetric and there are 'ears' (faces linked + * to only one other face) at two grid corners. + * + * Example old-style game ids, which should still work, and in + * which you should see the ears in the TL/BR corners on the + * first one and in the TL/BL corners on the second: + * + * 5x5t1:2c2a1a2a201a1a1a1112a1a2b1211f0b21a2a2a0a + * 5x6t1:a022a212h1a1d1a12c2b11a012b1a20d1a0a12e + */ + + g->num_faces = width * height * 2; + g->num_dots = (width + 1) * (height + 1); + g->faces = snewn(g->num_faces, grid_face); + g->dots = snewn(g->num_dots, grid_dot); + + /* generate dots */ + index = 0; + for (y = 0; y <= height; y++) { + for (x = 0; x <= width; x++) { + grid_dot *d = g->dots + index; + /* odd rows are offset to the right */ + d->order = 0; + d->edges = NULL; + d->faces = NULL; + d->x = x * 2 * vec_x + ((y % 2) ? vec_x : 0); + d->y = y * vec_y; + index++; + } } - } - /* generate faces */ - index = 0; - for (y = 0; y < height; y++) { - for (x = 0; x < width; x++) { - /* initialise two faces for this (x,y) */ - grid_face *f1 = g->faces + index; - grid_face *f2 = f1 + 1; - f1->edges = NULL; - f1->order = 3; - f1->dots = snewn(f1->order, grid_dot*); - f2->edges = NULL; - f2->order = 3; - f2->dots = snewn(f2->order, grid_dot*); - - /* face descriptions depend on whether the row-number is - * odd or even */ + /* generate faces */ + index = 0; + for (y = 0; y < height; y++) { + for (x = 0; x < width; x++) { + /* initialise two faces for this (x,y) */ + grid_face *f1 = g->faces + index; + grid_face *f2 = f1 + 1; + f1->edges = NULL; + f1->order = 3; + f1->dots = snewn(f1->order, grid_dot*); + f1->has_incentre = FALSE; + f2->edges = NULL; + f2->order = 3; + f2->dots = snewn(f2->order, grid_dot*); + f2->has_incentre = FALSE; + + /* face descriptions depend on whether the row-number is + * odd or even */ + if (y % 2) { + f1->dots[0] = g->dots + y * w + x; + f1->dots[1] = g->dots + (y + 1) * w + x + 1; + f1->dots[2] = g->dots + (y + 1) * w + x; + f2->dots[0] = g->dots + y * w + x; + f2->dots[1] = g->dots + y * w + x + 1; + f2->dots[2] = g->dots + (y + 1) * w + x + 1; + } else { + f1->dots[0] = g->dots + y * w + x; + f1->dots[1] = g->dots + y * w + x + 1; + f1->dots[2] = g->dots + (y + 1) * w + x; + f2->dots[0] = g->dots + y * w + x + 1; + f2->dots[1] = g->dots + (y + 1) * w + x + 1; + f2->dots[2] = g->dots + (y + 1) * w + x; + } + index += 2; + } + } + } else { + /* + * New-style approach, in which there are never any 'ears', + * and if height is even then the grid is nicely 4-way + * symmetric. + * + * Example new-style grids: + * + * 5x5t1:0_21120b11a1a01a1a00c1a0b211021c1h1a2a1a0a + * 5x6t1:0_a1212c22c2a02a2f22a0c12a110d0e1c0c0a101121a1 + */ + tree234 *points = newtree234(grid_point_cmp_fn); + /* Upper bounds - don't have to be exact */ + int max_faces = height * (2*width+1); + int max_dots = (height+1) * (width+1) * 4; + + g->faces = snewn(max_faces, grid_face); + g->dots = snewn(max_dots, grid_dot); + + for (y = 0; y < height; y++) { + /* + * Each row contains (width+1) triangles one way up, and + * (width) triangles the other way up. Which way up is + * which varies with parity of y. Also, the dots around + * each face will flip direction with parity of y, so we + * set up n1 and n2 to cope with that easily. + */ + int y0, y1, n1, n2; + y0 = y1 = y * vec_y; if (y % 2) { - f1->dots[0] = g->dots + y * w + x; - f1->dots[1] = g->dots + (y + 1) * w + x + 1; - f1->dots[2] = g->dots + (y + 1) * w + x; - f2->dots[0] = g->dots + y * w + x; - f2->dots[1] = g->dots + y * w + x + 1; - f2->dots[2] = g->dots + (y + 1) * w + x + 1; + y1 += vec_y; + n1 = 2; n2 = 1; } else { - f1->dots[0] = g->dots + y * w + x; - f1->dots[1] = g->dots + y * w + x + 1; - f1->dots[2] = g->dots + (y + 1) * w + x; - f2->dots[0] = g->dots + y * w + x + 1; - f2->dots[1] = g->dots + (y + 1) * w + x + 1; - f2->dots[2] = g->dots + (y + 1) * w + x; + y0 += vec_y; + n1 = 1; n2 = 2; + } + + for (x = 0; x <= width; x++) { + int x0 = 2*x * vec_x, x1 = x0 + vec_x, x2 = x1 + vec_x; + + /* + * If the grid has odd height, then we skip the first + * and last triangles on this row, otherwise they'll + * end up as ears. + */ + if (height % 2 == 1 && y == height-1 && (x == 0 || x == width)) + continue; + + grid_face_add_new(g, 3); + grid_face_set_dot(g, grid_get_dot(g, points, x0, y0), 0); + grid_face_set_dot(g, grid_get_dot(g, points, x1, y1), n1); + grid_face_set_dot(g, grid_get_dot(g, points, x2, y0), n2); + } + + for (x = 0; x < width; x++) { + int x0 = (2*x+1) * vec_x, x1 = x0 + vec_x, x2 = x1 + vec_x; + + grid_face_add_new(g, 3); + grid_face_set_dot(g, grid_get_dot(g, points, x0, y1), 0); + grid_face_set_dot(g, grid_get_dot(g, points, x1, y0), n2); + grid_face_set_dot(g, grid_get_dot(g, points, x2, y1), n1); } - index += 2; } - } - /* "+ width" takes us to the middle of the row, because each row has - * (2*width) faces. */ - g->middle_face = g->faces + (height / 2) * 2 * width + width; + freetree234(points); + assert(g->num_faces <= max_faces); + assert(g->num_dots <= max_dots); + } grid_make_consistent(g); return g; } -grid *grid_new_snubsquare(int width, int height) +#define SNUBSQUARE_TILESIZE 18 +/* Vector for side of triangle - ratio is close to sqrt(3) */ +#define SNUBSQUARE_A 15 +#define SNUBSQUARE_B 26 + +static void grid_size_snubsquare(int width, int height, + int *tilesize, int *xextent, int *yextent) +{ + int a = SNUBSQUARE_A; + int b = SNUBSQUARE_B; + + *tilesize = SNUBSQUARE_TILESIZE; + *xextent = (a+b) * (width-1) + a + b; + *yextent = (a+b) * (height-1) + a + b; +} + +static grid *grid_new_snubsquare(int width, int height, const char *desc) { int x, y; - /* Vector for side of triangle - ratio is close to sqrt(3) */ - int a = 15; - int b = 26; + int a = SNUBSQUARE_A; + int b = SNUBSQUARE_B; /* Upper bounds - don't have to be exact */ int max_faces = 3 * width * height; int max_dots = 2 * (width + 1) * (height + 1); - + tree234 *points; - grid *g = grid_new(); - g->tilesize = 18; + grid *g = grid_empty(); + g->tilesize = SNUBSQUARE_TILESIZE; g->faces = snewn(max_faces, grid_face); g->dots = snewn(max_dots, grid_dot); @@ -960,27 +1819,40 @@ grid *grid_new_snubsquare(int width, int height) freetree234(points); assert(g->num_faces <= max_faces); assert(g->num_dots <= max_dots); - g->middle_face = g->faces + (height/2) * width + (width/2); grid_make_consistent(g); return g; } -grid *grid_new_cairo(int width, int height) +#define CAIRO_TILESIZE 40 +/* Vector for side of pentagon - ratio is close to (4+sqrt(7))/3 */ +#define CAIRO_A 14 +#define CAIRO_B 31 + +static void grid_size_cairo(int width, int height, + int *tilesize, int *xextent, int *yextent) +{ + int b = CAIRO_B; /* a unused in determining grid size. */ + + *tilesize = CAIRO_TILESIZE; + *xextent = 2*b*(width-1) + 2*b; + *yextent = 2*b*(height-1) + 2*b; +} + +static grid *grid_new_cairo(int width, int height, const char *desc) { int x, y; - /* Vector for side of pentagon - ratio is close to (4+sqrt(7))/3 */ - int a = 14; - int b = 31; + int a = CAIRO_A; + int b = CAIRO_B; /* Upper bounds - don't have to be exact */ int max_faces = 2 * width * height; int max_dots = 3 * (width + 1) * (height + 1); - + tree234 *points; - grid *g = grid_new(); - g->tilesize = 40; + grid *g = grid_empty(); + g->tilesize = CAIRO_TILESIZE; g->faces = snewn(max_faces, grid_face); g->dots = snewn(max_dots, grid_dot); @@ -1053,18 +1925,32 @@ grid *grid_new_cairo(int width, int height) freetree234(points); assert(g->num_faces <= max_faces); assert(g->num_dots <= max_dots); - g->middle_face = g->faces + (height/2) * width + (width/2); grid_make_consistent(g); return g; } -grid *grid_new_greathexagonal(int width, int height) +#define GREATHEX_TILESIZE 18 +/* Vector for side of triangle - ratio is close to sqrt(3) */ +#define GREATHEX_A 15 +#define GREATHEX_B 26 + +static void grid_size_greathexagonal(int width, int height, + int *tilesize, int *xextent, int *yextent) +{ + int a = GREATHEX_A; + int b = GREATHEX_B; + + *tilesize = GREATHEX_TILESIZE; + *xextent = (3*a + b) * (width-1) + 4*a; + *yextent = (2*a + 2*b) * (height-1) + 3*b + a; +} + +static grid *grid_new_greathexagonal(int width, int height, const char *desc) { int x, y; - /* Vector for side of triangle - ratio is close to sqrt(3) */ - int a = 15; - int b = 26; + int a = GREATHEX_A; + int b = GREATHEX_B; /* Upper bounds - don't have to be exact */ int max_faces = 6 * (width + 1) * (height + 1); @@ -1072,8 +1958,8 @@ grid *grid_new_greathexagonal(int width, int height) tree234 *points; - grid *g = grid_new(); - g->tilesize = 18; + grid *g = grid_empty(); + g->tilesize = GREATHEX_TILESIZE; g->faces = snewn(max_faces, grid_face); g->dots = snewn(max_dots, grid_dot); @@ -1169,18 +2055,32 @@ grid *grid_new_greathexagonal(int width, int height) freetree234(points); assert(g->num_faces <= max_faces); assert(g->num_dots <= max_dots); - g->middle_face = g->faces + (height/2) * width + (width/2); grid_make_consistent(g); return g; } -grid *grid_new_octagonal(int width, int height) +#define OCTAGONAL_TILESIZE 40 +/* b/a approx sqrt(2) */ +#define OCTAGONAL_A 29 +#define OCTAGONAL_B 41 + +static void grid_size_octagonal(int width, int height, + int *tilesize, int *xextent, int *yextent) +{ + int a = OCTAGONAL_A; + int b = OCTAGONAL_B; + + *tilesize = OCTAGONAL_TILESIZE; + *xextent = (2*a + b) * width; + *yextent = (2*a + b) * height; +} + +static grid *grid_new_octagonal(int width, int height, const char *desc) { int x, y; - /* b/a approx sqrt(2) */ - int a = 29; - int b = 41; + int a = OCTAGONAL_A; + int b = OCTAGONAL_B; /* Upper bounds - don't have to be exact */ int max_faces = 2 * width * height; @@ -1188,8 +2088,8 @@ grid *grid_new_octagonal(int width, int height) tree234 *points; - grid *g = grid_new(); - g->tilesize = 40; + grid *g = grid_empty(); + g->tilesize = OCTAGONAL_TILESIZE; g->faces = snewn(max_faces, grid_face); g->dots = snewn(max_dots, grid_dot); @@ -1238,18 +2138,32 @@ grid *grid_new_octagonal(int width, int height) freetree234(points); assert(g->num_faces <= max_faces); assert(g->num_dots <= max_dots); - g->middle_face = g->faces + (height/2) * width + (width/2); grid_make_consistent(g); return g; } -grid *grid_new_kites(int width, int height) +#define KITE_TILESIZE 40 +/* b/a approx sqrt(3) */ +#define KITE_A 15 +#define KITE_B 26 + +static void grid_size_kites(int width, int height, + int *tilesize, int *xextent, int *yextent) +{ + int a = KITE_A; + int b = KITE_B; + + *tilesize = KITE_TILESIZE; + *xextent = 4*b * width + 2*b; + *yextent = 6*a * (height-1) + 8*a; +} + +static grid *grid_new_kites(int width, int height, const char *desc) { int x, y; - /* b/a approx sqrt(3) */ - int a = 15; - int b = 26; + int a = KITE_A; + int b = KITE_B; /* Upper bounds - don't have to be exact */ int max_faces = 6 * width * height; @@ -1257,8 +2171,8 @@ grid *grid_new_kites(int width, int height) tree234 *points; - grid *g = grid_new(); - g->tilesize = 40; + grid *g = grid_empty(); + g->tilesize = KITE_TILESIZE; g->faces = snewn(max_faces, grid_face); g->dots = snewn(max_dots, grid_dot); @@ -1344,10 +2258,639 @@ grid *grid_new_kites(int width, int height) freetree234(points); assert(g->num_faces <= max_faces); assert(g->num_dots <= max_dots); - g->middle_face = g->faces + 6 * ((height/2) * width + (width/2)); grid_make_consistent(g); return g; } +#define FLORET_TILESIZE 150 +/* -py/px is close to tan(30 - atan(sqrt(3)/9)) + * using py=26 makes everything lean to the left, rather than right + */ +#define FLORET_PX 75 +#define FLORET_PY -26 + +static void grid_size_floret(int width, int height, + int *tilesize, int *xextent, int *yextent) +{ + int px = FLORET_PX, py = FLORET_PY; /* |( 75, -26)| = 79.43 */ + int qx = 4*px/5, qy = -py*2; /* |( 60, 52)| = 79.40 */ + int ry = qy-py; + /* rx unused in determining grid size. */ + + *tilesize = FLORET_TILESIZE; + *xextent = (6*px+3*qx)/2 * (width-1) + 4*qx + 2*px; + *yextent = (5*qy-4*py) * (height-1) + 4*qy + 2*ry; +} + +static grid *grid_new_floret(int width, int height, const char *desc) +{ + int x, y; + /* Vectors for sides; weird numbers needed to keep puzzle aligned with window + * -py/px is close to tan(30 - atan(sqrt(3)/9)) + * using py=26 makes everything lean to the left, rather than right + */ + int px = FLORET_PX, py = FLORET_PY; /* |( 75, -26)| = 79.43 */ + int qx = 4*px/5, qy = -py*2; /* |( 60, 52)| = 79.40 */ + int rx = qx-px, ry = qy-py; /* |(-15, 78)| = 79.38 */ + + /* Upper bounds - don't have to be exact */ + int max_faces = 6 * width * height; + int max_dots = 9 * (width + 1) * (height + 1); + + tree234 *points; + + grid *g = grid_empty(); + g->tilesize = FLORET_TILESIZE; + g->faces = snewn(max_faces, grid_face); + g->dots = snewn(max_dots, grid_dot); + + points = newtree234(grid_point_cmp_fn); + + /* generate pentagonal faces */ + for (y = 0; y < height; y++) { + for (x = 0; x < width; x++) { + grid_dot *d; + /* face centre */ + int cx = (6*px+3*qx)/2 * x; + int cy = (4*py-5*qy) * y; + if (x % 2) + cy -= (4*py-5*qy)/2; + else if (y && y == height-1) + continue; /* make better looking grids? try 3x3 for instance */ + + grid_face_add_new(g, 5); + d = grid_get_dot(g, points, cx , cy ); grid_face_set_dot(g, d, 0); + d = grid_get_dot(g, points, cx+2*rx , cy+2*ry ); grid_face_set_dot(g, d, 1); + d = grid_get_dot(g, points, cx+2*rx+qx, cy+2*ry+qy); grid_face_set_dot(g, d, 2); + d = grid_get_dot(g, points, cx+2*qx+rx, cy+2*qy+ry); grid_face_set_dot(g, d, 3); + d = grid_get_dot(g, points, cx+2*qx , cy+2*qy ); grid_face_set_dot(g, d, 4); + + grid_face_add_new(g, 5); + d = grid_get_dot(g, points, cx , cy ); grid_face_set_dot(g, d, 0); + d = grid_get_dot(g, points, cx+2*qx , cy+2*qy ); grid_face_set_dot(g, d, 1); + d = grid_get_dot(g, points, cx+2*qx+px, cy+2*qy+py); grid_face_set_dot(g, d, 2); + d = grid_get_dot(g, points, cx+2*px+qx, cy+2*py+qy); grid_face_set_dot(g, d, 3); + d = grid_get_dot(g, points, cx+2*px , cy+2*py ); grid_face_set_dot(g, d, 4); + + grid_face_add_new(g, 5); + d = grid_get_dot(g, points, cx , cy ); grid_face_set_dot(g, d, 0); + d = grid_get_dot(g, points, cx+2*px , cy+2*py ); grid_face_set_dot(g, d, 1); + d = grid_get_dot(g, points, cx+2*px-rx, cy+2*py-ry); grid_face_set_dot(g, d, 2); + d = grid_get_dot(g, points, cx-2*rx+px, cy-2*ry+py); grid_face_set_dot(g, d, 3); + d = grid_get_dot(g, points, cx-2*rx , cy-2*ry ); grid_face_set_dot(g, d, 4); + + grid_face_add_new(g, 5); + d = grid_get_dot(g, points, cx , cy ); grid_face_set_dot(g, d, 0); + d = grid_get_dot(g, points, cx-2*rx , cy-2*ry ); grid_face_set_dot(g, d, 1); + d = grid_get_dot(g, points, cx-2*rx-qx, cy-2*ry-qy); grid_face_set_dot(g, d, 2); + d = grid_get_dot(g, points, cx-2*qx-rx, cy-2*qy-ry); grid_face_set_dot(g, d, 3); + d = grid_get_dot(g, points, cx-2*qx , cy-2*qy ); grid_face_set_dot(g, d, 4); + + grid_face_add_new(g, 5); + d = grid_get_dot(g, points, cx , cy ); grid_face_set_dot(g, d, 0); + d = grid_get_dot(g, points, cx-2*qx , cy-2*qy ); grid_face_set_dot(g, d, 1); + d = grid_get_dot(g, points, cx-2*qx-px, cy-2*qy-py); grid_face_set_dot(g, d, 2); + d = grid_get_dot(g, points, cx-2*px-qx, cy-2*py-qy); grid_face_set_dot(g, d, 3); + d = grid_get_dot(g, points, cx-2*px , cy-2*py ); grid_face_set_dot(g, d, 4); + + grid_face_add_new(g, 5); + d = grid_get_dot(g, points, cx , cy ); grid_face_set_dot(g, d, 0); + d = grid_get_dot(g, points, cx-2*px , cy-2*py ); grid_face_set_dot(g, d, 1); + d = grid_get_dot(g, points, cx-2*px+rx, cy-2*py+ry); grid_face_set_dot(g, d, 2); + d = grid_get_dot(g, points, cx+2*rx-px, cy+2*ry-py); grid_face_set_dot(g, d, 3); + d = grid_get_dot(g, points, cx+2*rx , cy+2*ry ); grid_face_set_dot(g, d, 4); + } + } + + freetree234(points); + assert(g->num_faces <= max_faces); + assert(g->num_dots <= max_dots); + + grid_make_consistent(g); + return g; +} + +/* DODEC_* are used for dodecagonal and great-dodecagonal grids. */ +#define DODEC_TILESIZE 26 +/* Vector for side of triangle - ratio is close to sqrt(3) */ +#define DODEC_A 15 +#define DODEC_B 26 + +static void grid_size_dodecagonal(int width, int height, + int *tilesize, int *xextent, int *yextent) +{ + int a = DODEC_A; + int b = DODEC_B; + + *tilesize = DODEC_TILESIZE; + *xextent = (4*a + 2*b) * (width-1) + 3*(2*a + b); + *yextent = (3*a + 2*b) * (height-1) + 2*(2*a + b); +} + +static grid *grid_new_dodecagonal(int width, int height, const char *desc) +{ + int x, y; + int a = DODEC_A; + int b = DODEC_B; + + /* Upper bounds - don't have to be exact */ + int max_faces = 3 * width * height; + int max_dots = 14 * width * height; + + tree234 *points; + + grid *g = grid_empty(); + g->tilesize = DODEC_TILESIZE; + g->faces = snewn(max_faces, grid_face); + g->dots = snewn(max_dots, grid_dot); + + points = newtree234(grid_point_cmp_fn); + + for (y = 0; y < height; y++) { + for (x = 0; x < width; x++) { + grid_dot *d; + /* centre of dodecagon */ + int px = (4*a + 2*b) * x; + int py = (3*a + 2*b) * y; + if (y % 2) + px += 2*a + b; + + /* dodecagon */ + grid_face_add_new(g, 12); + d = grid_get_dot(g, points, px + ( a ), py - (2*a + b)); grid_face_set_dot(g, d, 0); + d = grid_get_dot(g, points, px + ( a + b), py - ( a + b)); grid_face_set_dot(g, d, 1); + d = grid_get_dot(g, points, px + (2*a + b), py - ( a )); grid_face_set_dot(g, d, 2); + d = grid_get_dot(g, points, px + (2*a + b), py + ( a )); grid_face_set_dot(g, d, 3); + d = grid_get_dot(g, points, px + ( a + b), py + ( a + b)); grid_face_set_dot(g, d, 4); + d = grid_get_dot(g, points, px + ( a ), py + (2*a + b)); grid_face_set_dot(g, d, 5); + d = grid_get_dot(g, points, px - ( a ), py + (2*a + b)); grid_face_set_dot(g, d, 6); + d = grid_get_dot(g, points, px - ( a + b), py + ( a + b)); grid_face_set_dot(g, d, 7); + d = grid_get_dot(g, points, px - (2*a + b), py + ( a )); grid_face_set_dot(g, d, 8); + d = grid_get_dot(g, points, px - (2*a + b), py - ( a )); grid_face_set_dot(g, d, 9); + d = grid_get_dot(g, points, px - ( a + b), py - ( a + b)); grid_face_set_dot(g, d, 10); + d = grid_get_dot(g, points, px - ( a ), py - (2*a + b)); grid_face_set_dot(g, d, 11); + + /* triangle below dodecagon */ + if ((y < height - 1 && (x < width - 1 || !(y % 2)) && (x > 0 || (y % 2)))) { + grid_face_add_new(g, 3); + d = grid_get_dot(g, points, px + a, py + (2*a + b)); grid_face_set_dot(g, d, 0); + d = grid_get_dot(g, points, px , py + (2*a + 2*b)); grid_face_set_dot(g, d, 1); + d = grid_get_dot(g, points, px - a, py + (2*a + b)); grid_face_set_dot(g, d, 2); + } + + /* triangle above dodecagon */ + if ((y && (x < width - 1 || !(y % 2)) && (x > 0 || (y % 2)))) { + grid_face_add_new(g, 3); + d = grid_get_dot(g, points, px - a, py - (2*a + b)); grid_face_set_dot(g, d, 0); + d = grid_get_dot(g, points, px , py - (2*a + 2*b)); grid_face_set_dot(g, d, 1); + d = grid_get_dot(g, points, px + a, py - (2*a + b)); grid_face_set_dot(g, d, 2); + } + } + } + + freetree234(points); + assert(g->num_faces <= max_faces); + assert(g->num_dots <= max_dots); + + grid_make_consistent(g); + return g; +} + +static void grid_size_greatdodecagonal(int width, int height, + int *tilesize, int *xextent, int *yextent) +{ + int a = DODEC_A; + int b = DODEC_B; + + *tilesize = DODEC_TILESIZE; + *xextent = (6*a + 2*b) * (width-1) + 2*(2*a + b) + 3*a + b; + *yextent = (3*a + 3*b) * (height-1) + 2*(2*a + b); +} + +static grid *grid_new_greatdodecagonal(int width, int height, const char *desc) +{ + int x, y; + /* Vector for side of triangle - ratio is close to sqrt(3) */ + int a = DODEC_A; + int b = DODEC_B; + + /* Upper bounds - don't have to be exact */ + int max_faces = 30 * width * height; + int max_dots = 200 * width * height; + + tree234 *points; + + grid *g = grid_empty(); + g->tilesize = DODEC_TILESIZE; + g->faces = snewn(max_faces, grid_face); + g->dots = snewn(max_dots, grid_dot); + + points = newtree234(grid_point_cmp_fn); + + for (y = 0; y < height; y++) { + for (x = 0; x < width; x++) { + grid_dot *d; + /* centre of dodecagon */ + int px = (6*a + 2*b) * x; + int py = (3*a + 3*b) * y; + if (y % 2) + px += 3*a + b; + + /* dodecagon */ + grid_face_add_new(g, 12); + d = grid_get_dot(g, points, px + ( a ), py - (2*a + b)); grid_face_set_dot(g, d, 0); + d = grid_get_dot(g, points, px + ( a + b), py - ( a + b)); grid_face_set_dot(g, d, 1); + d = grid_get_dot(g, points, px + (2*a + b), py - ( a )); grid_face_set_dot(g, d, 2); + d = grid_get_dot(g, points, px + (2*a + b), py + ( a )); grid_face_set_dot(g, d, 3); + d = grid_get_dot(g, points, px + ( a + b), py + ( a + b)); grid_face_set_dot(g, d, 4); + d = grid_get_dot(g, points, px + ( a ), py + (2*a + b)); grid_face_set_dot(g, d, 5); + d = grid_get_dot(g, points, px - ( a ), py + (2*a + b)); grid_face_set_dot(g, d, 6); + d = grid_get_dot(g, points, px - ( a + b), py + ( a + b)); grid_face_set_dot(g, d, 7); + d = grid_get_dot(g, points, px - (2*a + b), py + ( a )); grid_face_set_dot(g, d, 8); + d = grid_get_dot(g, points, px - (2*a + b), py - ( a )); grid_face_set_dot(g, d, 9); + d = grid_get_dot(g, points, px - ( a + b), py - ( a + b)); grid_face_set_dot(g, d, 10); + d = grid_get_dot(g, points, px - ( a ), py - (2*a + b)); grid_face_set_dot(g, d, 11); + + /* hexagon below dodecagon */ + if (y < height - 1 && (x < width - 1 || !(y % 2)) && (x > 0 || (y % 2))) { + grid_face_add_new(g, 6); + d = grid_get_dot(g, points, px + a, py + (2*a + b)); grid_face_set_dot(g, d, 0); + d = grid_get_dot(g, points, px + 2*a, py + (2*a + 2*b)); grid_face_set_dot(g, d, 1); + d = grid_get_dot(g, points, px + a, py + (2*a + 3*b)); grid_face_set_dot(g, d, 2); + d = grid_get_dot(g, points, px - a, py + (2*a + 3*b)); grid_face_set_dot(g, d, 3); + d = grid_get_dot(g, points, px - 2*a, py + (2*a + 2*b)); grid_face_set_dot(g, d, 4); + d = grid_get_dot(g, points, px - a, py + (2*a + b)); grid_face_set_dot(g, d, 5); + } + + /* hexagon above dodecagon */ + if (y && (x < width - 1 || !(y % 2)) && (x > 0 || (y % 2))) { + grid_face_add_new(g, 6); + d = grid_get_dot(g, points, px - a, py - (2*a + b)); grid_face_set_dot(g, d, 0); + d = grid_get_dot(g, points, px - 2*a, py - (2*a + 2*b)); grid_face_set_dot(g, d, 1); + d = grid_get_dot(g, points, px - a, py - (2*a + 3*b)); grid_face_set_dot(g, d, 2); + d = grid_get_dot(g, points, px + a, py - (2*a + 3*b)); grid_face_set_dot(g, d, 3); + d = grid_get_dot(g, points, px + 2*a, py - (2*a + 2*b)); grid_face_set_dot(g, d, 4); + d = grid_get_dot(g, points, px + a, py - (2*a + b)); grid_face_set_dot(g, d, 5); + } + + /* square on right of dodecagon */ + if (x < width - 1) { + grid_face_add_new(g, 4); + d = grid_get_dot(g, points, px + 2*a + b, py - a); grid_face_set_dot(g, d, 0); + d = grid_get_dot(g, points, px + 4*a + b, py - a); grid_face_set_dot(g, d, 1); + d = grid_get_dot(g, points, px + 4*a + b, py + a); grid_face_set_dot(g, d, 2); + d = grid_get_dot(g, points, px + 2*a + b, py + a); grid_face_set_dot(g, d, 3); + } + + /* square on top right of dodecagon */ + if (y && (x < width - 1 || !(y % 2))) { + grid_face_add_new(g, 4); + d = grid_get_dot(g, points, px + ( a ), py - (2*a + b)); grid_face_set_dot(g, d, 0); + d = grid_get_dot(g, points, px + (2*a ), py - (2*a + 2*b)); grid_face_set_dot(g, d, 1); + d = grid_get_dot(g, points, px + (2*a + b), py - ( a + 2*b)); grid_face_set_dot(g, d, 2); + d = grid_get_dot(g, points, px + ( a + b), py - ( a + b)); grid_face_set_dot(g, d, 3); + } + + /* square on top left of dodecagon */ + if (y && (x || (y % 2))) { + grid_face_add_new(g, 4); + d = grid_get_dot(g, points, px - ( a + b), py - ( a + b)); grid_face_set_dot(g, d, 0); + d = grid_get_dot(g, points, px - (2*a + b), py - ( a + 2*b)); grid_face_set_dot(g, d, 1); + d = grid_get_dot(g, points, px - (2*a ), py - (2*a + 2*b)); grid_face_set_dot(g, d, 2); + d = grid_get_dot(g, points, px - ( a ), py - (2*a + b)); grid_face_set_dot(g, d, 3); + } + } + } + + freetree234(points); + assert(g->num_faces <= max_faces); + assert(g->num_dots <= max_dots); + + grid_make_consistent(g); + return g; +} + +typedef struct setface_ctx +{ + int xmin, xmax, ymin, ymax; + + grid *g; + tree234 *points; +} setface_ctx; + +static double round_int_nearest_away(double r) +{ + return (r > 0.0) ? floor(r + 0.5) : ceil(r - 0.5); +} + +static int set_faces(penrose_state *state, vector *vs, int n, int depth) +{ + setface_ctx *sf_ctx = (setface_ctx *)state->ctx; + int i; + int xs[4], ys[4]; + + if (depth < state->max_depth) return 0; +#ifdef DEBUG_PENROSE + if (n != 4) return 0; /* triangles are sent as debugging. */ +#endif + + for (i = 0; i < n; i++) { + double tx = v_x(vs, i), ty = v_y(vs, i); + + xs[i] = (int)round_int_nearest_away(tx); + ys[i] = (int)round_int_nearest_away(ty); + + if (xs[i] < sf_ctx->xmin || xs[i] > sf_ctx->xmax) return 0; + if (ys[i] < sf_ctx->ymin || ys[i] > sf_ctx->ymax) return 0; + } + + grid_face_add_new(sf_ctx->g, n); + debug(("penrose: new face l=%f gen=%d...", + penrose_side_length(state->start_size, depth), depth)); + for (i = 0; i < n; i++) { + grid_dot *d = grid_get_dot(sf_ctx->g, sf_ctx->points, + xs[i], ys[i]); + grid_face_set_dot(sf_ctx->g, d, i); + debug((" ... dot 0x%x (%d,%d) (was %2.2f,%2.2f)", + d, d->x, d->y, v_x(vs, i), v_y(vs, i))); + } + + return 0; +} + +#define PENROSE_TILESIZE 100 + +static void grid_size_penrose(int width, int height, + int *tilesize, int *xextent, int *yextent) +{ + int l = PENROSE_TILESIZE; + + *tilesize = l; + *xextent = l * width; + *yextent = l * height; +} + +static grid *grid_new_penrose(int width, int height, int which, const char *desc); /* forward reference */ + +static char *grid_new_desc_penrose(grid_type type, int width, int height, random_state *rs) +{ + int tilesize = PENROSE_TILESIZE, startsz, depth, xoff, yoff, aoff; + double outer_radius; + int inner_radius; + char gd[255]; + int which = (type == GRID_PENROSE_P2 ? PENROSE_P2 : PENROSE_P3); + grid *g; + + while (1) { + /* We want to produce a random bit of penrose tiling, so we + * calculate a random offset (within the patch that penrose.c + * calculates for us) and an angle (multiple of 36) to rotate + * the patch. */ + + penrose_calculate_size(which, tilesize, width, height, + &outer_radius, &startsz, &depth); + + /* Calculate radius of (circumcircle of) patch, subtract from + * radius calculated. */ + inner_radius = (int)(outer_radius - sqrt(width*width + height*height)); + + /* Pick a random offset (the easy way: choose within outer + * square, discarding while it's outside the circle) */ + do { + xoff = random_upto(rs, 2*inner_radius) - inner_radius; + yoff = random_upto(rs, 2*inner_radius) - inner_radius; + } while (sqrt(xoff*xoff+yoff*yoff) > inner_radius); + + aoff = random_upto(rs, 360/36) * 36; + + debug(("grid_desc: ts %d, %dx%d patch, orad %2.2f irad %d", + tilesize, width, height, outer_radius, inner_radius)); + debug((" -> xoff %d yoff %d aoff %d", xoff, yoff, aoff)); + + sprintf(gd, "G%d,%d,%d", xoff, yoff, aoff); + + /* + * Now test-generate our grid, to make sure it actually + * produces something. + */ + g = grid_new_penrose(width, height, which, gd); + if (g) { + grid_free(g); + break; + } + /* If not, go back to the top of this while loop and try again + * with a different random offset. */ + } + + return dupstr(gd); +} + +static char *grid_validate_desc_penrose(grid_type type, int width, int height, + const char *desc) +{ + int tilesize = PENROSE_TILESIZE, startsz, depth, xoff, yoff, aoff, inner_radius; + double outer_radius; + int which = (type == GRID_PENROSE_P2 ? PENROSE_P2 : PENROSE_P3); + grid *g; + + if (!desc) + return "Missing grid description string."; + + penrose_calculate_size(which, tilesize, width, height, + &outer_radius, &startsz, &depth); + inner_radius = (int)(outer_radius - sqrt(width*width + height*height)); + + if (sscanf(desc, "G%d,%d,%d", &xoff, &yoff, &aoff) != 3) + return "Invalid format grid description string."; + + if (sqrt(xoff*xoff + yoff*yoff) > inner_radius) + return "Patch offset out of bounds."; + if ((aoff % 36) != 0 || aoff < 0 || aoff >= 360) + return "Angle offset out of bounds."; + + /* + * Test-generate to ensure these parameters don't end us up with + * no grid at all. + */ + g = grid_new_penrose(width, height, which, desc); + if (!g) + return "Patch coordinates do not identify a usable grid fragment"; + grid_free(g); + + return NULL; +} + +/* + * We're asked for a grid of a particular size, and we generate enough + * of the tiling so we can be sure to have enough random grid from which + * to pick. + */ + +static grid *grid_new_penrose(int width, int height, int which, const char *desc) +{ + int max_faces, max_dots, tilesize = PENROSE_TILESIZE; + int xsz, ysz, xoff, yoff, aoff; + double rradius; + + tree234 *points; + grid *g; + + penrose_state ps; + setface_ctx sf_ctx; + + penrose_calculate_size(which, tilesize, width, height, + &rradius, &ps.start_size, &ps.max_depth); + + debug(("penrose: w%d h%d, tile size %d, start size %d, depth %d", + width, height, tilesize, ps.start_size, ps.max_depth)); + + ps.new_tile = set_faces; + ps.ctx = &sf_ctx; + + max_faces = (width*3) * (height*3); /* somewhat paranoid... */ + max_dots = max_faces * 4; /* ditto... */ + + g = grid_empty(); + g->tilesize = tilesize; + g->faces = snewn(max_faces, grid_face); + g->dots = snewn(max_dots, grid_dot); + + points = newtree234(grid_point_cmp_fn); + + memset(&sf_ctx, 0, sizeof(sf_ctx)); + sf_ctx.g = g; + sf_ctx.points = points; + + if (desc != NULL) { + if (sscanf(desc, "G%d,%d,%d", &xoff, &yoff, &aoff) != 3) + assert(!"Invalid grid description."); + } else { + xoff = yoff = aoff = 0; + } + + xsz = width * tilesize; + ysz = height * tilesize; + + sf_ctx.xmin = xoff - xsz/2; + sf_ctx.xmax = xoff + xsz/2; + sf_ctx.ymin = yoff - ysz/2; + sf_ctx.ymax = yoff + ysz/2; + + debug(("penrose: centre (%f, %f) xsz %f ysz %f", + 0.0, 0.0, xsz, ysz)); + debug(("penrose: x range (%f --> %f), y range (%f --> %f)", + sf_ctx.xmin, sf_ctx.xmax, sf_ctx.ymin, sf_ctx.ymax)); + + penrose(&ps, which, aoff); + + freetree234(points); + assert(g->num_faces <= max_faces); + assert(g->num_dots <= max_dots); + + debug(("penrose: %d faces total (equivalent to %d wide by %d high)", + g->num_faces, g->num_faces/height, g->num_faces/width)); + + /* + * Return NULL if we ended up with an empty grid, either because + * the initial generation was over too small a rectangle to + * encompass any face or because grid_trim_vigorously ended up + * removing absolutely everything. + */ + if (g->num_faces == 0 || g->num_dots == 0) { + grid_free(g); + return NULL; + } + grid_trim_vigorously(g); + if (g->num_faces == 0 || g->num_dots == 0) { + grid_free(g); + return NULL; + } + + grid_make_consistent(g); + + /* + * Centre the grid in its originally promised rectangle. + */ + g->lowest_x -= ((sf_ctx.xmax - sf_ctx.xmin) - + (g->highest_x - g->lowest_x)) / 2; + g->highest_x = g->lowest_x + (sf_ctx.xmax - sf_ctx.xmin); + g->lowest_y -= ((sf_ctx.ymax - sf_ctx.ymin) - + (g->highest_y - g->lowest_y)) / 2; + g->highest_y = g->lowest_y + (sf_ctx.ymax - sf_ctx.ymin); + + return g; +} + +static void grid_size_penrose_p2_kite(int width, int height, + int *tilesize, int *xextent, int *yextent) +{ + grid_size_penrose(width, height, tilesize, xextent, yextent); +} + +static void grid_size_penrose_p3_thick(int width, int height, + int *tilesize, int *xextent, int *yextent) +{ + grid_size_penrose(width, height, tilesize, xextent, yextent); +} + +static grid *grid_new_penrose_p2_kite(int width, int height, const char *desc) +{ + return grid_new_penrose(width, height, PENROSE_P2, desc); +} + +static grid *grid_new_penrose_p3_thick(int width, int height, const char *desc) +{ + return grid_new_penrose(width, height, PENROSE_P3, desc); +} + /* ----------- End of grid generators ------------- */ + +#define FNNEW(upper,lower) &grid_new_ ## lower, +#define FNSZ(upper,lower) &grid_size_ ## lower, + +static grid *(*(grid_news[]))(int, int, const char*) = { GRIDGEN_LIST(FNNEW) }; +static void(*(grid_sizes[]))(int, int, int*, int*, int*) = { GRIDGEN_LIST(FNSZ) }; + +char *grid_new_desc(grid_type type, int width, int height, random_state *rs) +{ + if (type == GRID_PENROSE_P2 || type == GRID_PENROSE_P3) { + return grid_new_desc_penrose(type, width, height, rs); + } else if (type == GRID_TRIANGULAR) { + return dupstr("0"); /* up-to-date version of triangular grid */ + } else { + return NULL; + } +} + +char *grid_validate_desc(grid_type type, int width, int height, + const char *desc) +{ + if (type == GRID_PENROSE_P2 || type == GRID_PENROSE_P3) { + return grid_validate_desc_penrose(type, width, height, desc); + } else if (type == GRID_TRIANGULAR) { + return grid_validate_desc_triangular(type, width, height, desc); + } else { + if (desc != NULL) + return "Grid description strings not used with this grid type"; + return NULL; + } +} + +grid *grid_new(grid_type type, int width, int height, const char *desc) +{ + char *err = grid_validate_desc(type, width, height, desc); + if (err) assert(!"Invalid grid description."); + + return grid_news[type](width, height, desc); +} + +void grid_compute_size(grid_type type, int width, int height, + int *tilesize, int *xextent, int *yextent) +{ + grid_sizes[type](width, height, tilesize, xextent, yextent); +} + +/* ----------- End of grid helpers ------------- */ + +/* vim: set shiftwidth=4 tabstop=8: */