From James Harvey (via a period of collaborative polishing), a patch

to add two kinds of Penrose tiling to the grid types supported by
Loopy.

This has involved a certain amount of infrastructure work, because of
course the whole point of Penrose tilings is that they don't have to
be the same every time: so now grid.c has grown the capacity to
describe its grids as strings, and reconstitute them from those string
descriptions. Hence a Penrose Loopy game description consists of a
string identifying a particular piece of Penrose tiling, followed by
the normal Loopy clue encoding.

All the existing grid types decline to provide a grid description
string, so their Loopy game descriptions have not changed encoding.

[originally from svn r9159]
This commit is contained in:
Simon Tatham
2011-04-24 09:10:52 +00:00
parent f390d0d7ff
commit 62c20496bf
6 changed files with 1590 additions and 177 deletions

811
grid.c

File diff suppressed because it is too large Load Diff

43
grid.h
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@ -9,6 +9,8 @@
#ifndef PUZZLES_GRID_H
#define PUZZLES_GRID_H
#include "puzzles.h" /* for random_state */
/* Useful macros */
#define SQ(x) ( (x) * (x) )
@ -89,22 +91,41 @@ typedef struct grid {
int refcount;
} grid;
grid *grid_new_square(int width, int height);
grid *grid_new_honeycomb(int width, int height);
grid *grid_new_triangular(int width, int height);
grid *grid_new_snubsquare(int width, int height);
grid *grid_new_cairo(int width, int height);
grid *grid_new_greathexagonal(int width, int height);
grid *grid_new_octagonal(int width, int height);
grid *grid_new_kites(int width, int height);
grid *grid_new_floret(int width, int height);
grid *grid_new_dodecagonal(int width, int height);
grid *grid_new_greatdodecagonal(int width, int height);
/* Grids are specified by type: GRID_SQUARE, GRID_KITE, etc. */
#define GRIDGEN_LIST(A) \
A(SQUARE,square) \
A(HONEYCOMB,honeycomb) \
A(TRIANGULAR,triangular) \
A(SNUBSQUARE,snubsquare) \
A(CAIRO,cairo) \
A(GREATHEXAGONAL,greathexagonal) \
A(OCTAGONAL,octagonal) \
A(KITE,kites) \
A(FLORET,floret) \
A(DODECAGONAL,dodecagonal) \
A(GREATDODECAGONAL,greatdodecagonal) \
A(PENROSE_P2,penrose_p2_kite) \
A(PENROSE_P3,penrose_p3_thick)
#define ENUM(upper,lower) GRID_ ## upper,
typedef enum grid_type { GRIDGEN_LIST(ENUM) GRID_TYPE_MAX } grid_type;
#undef ENUM
/* Free directly after use if non-NULL. Will never contain an underscore
* (so clients can safely use that as a separator). */
char *grid_new_desc(grid_type type, int width, int height, random_state *rs);
char *grid_validate_desc(grid_type type, int width, int height, char *desc);
grid *grid_new(grid_type type, int width, int height, char *desc);
void grid_free(grid *g);
grid_edge *grid_nearest_edge(grid *g, int x, int y);
void grid_compute_size(grid_type type, int width, int height,
int *tilesize, int *xextent, int *yextent);
void grid_find_incentre(grid_face *f);
#endif /* PUZZLES_GRID_H */

View File

@ -1,6 +1,6 @@
# -*- makefile -*-
LOOPY_EXTRA = tree234 dsf grid
LOOPY_EXTRA = tree234 dsf grid penrose
loopy : [X] GTK COMMON loopy LOOPY_EXTRA loopy-icon|no-icon
@ -9,6 +9,13 @@ loopy : [G] WINDOWS COMMON loopy LOOPY_EXTRA loopy.res|noicon.res
loopysolver : [U] loopy[STANDALONE_SOLVER] LOOPY_EXTRA STANDALONE m.lib
loopysolver : [C] loopy[STANDALONE_SOLVER] LOOPY_EXTRA STANDALONE
#penrose : [U] penrose[TEST_PENROSE] STANDALONE m.lib
#penrose : [C] penrose[TEST_PENROSE] STANDALONE
#test-basis : [U] penrose[TEST_VECTORS] tree234 STANDALONE m.lib
#test-basis : [C] penrose[TEST_VECTORS] tree234 STANDALONE
ALL += loopy[COMBINED] LOOPY_EXTRA
!begin gtk

209
loopy.c
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@ -107,7 +107,7 @@ enum {
};
struct game_state {
grid *game_grid;
grid *game_grid; /* ref-counted (internally) */
/* Put -1 in a face that doesn't get a clue */
signed char *clues;
@ -207,10 +207,6 @@ struct game_params {
int w, h;
int diff;
int type;
/* Grid generation is expensive, so keep a (ref-counted) reference to the
* grid for these parameters, and only generate when required. */
grid *game_grid;
};
/* line_drawstate is the same as line_state, but with the extra ERROR
@ -247,29 +243,31 @@ static void check_caches(const solver_state* sstate);
/* ------- List of grid generators ------- */
#define GRIDLIST(A) \
A(Squares,grid_new_square,3,3) \
A(Triangular,grid_new_triangular,3,3) \
A(Honeycomb,grid_new_honeycomb,3,3) \
A(Snub-Square,grid_new_snubsquare,3,3) \
A(Cairo,grid_new_cairo,3,4) \
A(Great-Hexagonal,grid_new_greathexagonal,3,3) \
A(Octagonal,grid_new_octagonal,3,3) \
A(Kites,grid_new_kites,3,3) \
A(Floret,grid_new_floret,1,2) \
A(Dodecagonal,grid_new_dodecagonal,2,2) \
A(Great-Dodecagonal,grid_new_greatdodecagonal,2,2)
A(Squares,GRID_SQUARE,3,3) \
A(Triangular,GRID_TRIANGULAR,3,3) \
A(Honeycomb,GRID_HONEYCOMB,3,3) \
A(Snub-Square,GRID_SNUBSQUARE,3,3) \
A(Cairo,GRID_CAIRO,3,4) \
A(Great-Hexagonal,GRID_GREATHEXAGONAL,3,3) \
A(Octagonal,GRID_OCTAGONAL,3,3) \
A(Kites,GRID_KITE,3,3) \
A(Floret,GRID_FLORET,1,2) \
A(Dodecagonal,GRID_DODECAGONAL,2,2) \
A(Great-Dodecagonal,GRID_GREATDODECAGONAL,2,2) \
A(Penrose (kite/dart),GRID_PENROSE_P2,3,3) \
A(Penrose (rhombs),GRID_PENROSE_P3,3,3)
#define GRID_NAME(title,fn,amin,omin) #title,
#define GRID_CONFIG(title,fn,amin,omin) ":" #title
#define GRID_FN(title,fn,amin,omin) &fn,
#define GRID_SIZES(title,fn,amin,omin) \
#define GRID_NAME(title,type,amin,omin) #title,
#define GRID_CONFIG(title,type,amin,omin) ":" #title
#define GRID_TYPE(title,type,amin,omin) type,
#define GRID_SIZES(title,type,amin,omin) \
{amin, omin, \
"Width and height for this grid type must both be at least " #amin, \
"At least one of width and height for this grid type must be at least " #omin,},
static char const *const gridnames[] = { GRIDLIST(GRID_NAME) };
#define GRID_CONFIGS GRIDLIST(GRID_CONFIG)
static grid * (*(grid_fns[]))(int w, int h) = { GRIDLIST(GRID_FN) };
#define NUM_GRID_TYPES (sizeof(grid_fns) / sizeof(grid_fns[0]))
static grid_type grid_types[] = { GRIDLIST(GRID_TYPE) };
#define NUM_GRID_TYPES (sizeof(grid_types) / sizeof(grid_types[0]))
static const struct {
int amin, omin;
char *aerr, *oerr;
@ -277,13 +275,10 @@ static const struct {
/* Generates a (dynamically allocated) new grid, according to the
* type and size requested in params. Does nothing if the grid is already
* generated. The allocated grid is owned by the params object, and will be
* freed in free_params(). */
static void params_generate_grid(game_params *params)
* generated. */
static grid *loopy_generate_grid(game_params *params, char *grid_desc)
{
if (!params->game_grid) {
params->game_grid = grid_fns[params->type](params->w, params->h);
}
return grid_new(grid_types[params->type], params->w, params->h, grid_desc);
}
/* ----------------------------------------------------------------------
@ -480,8 +475,6 @@ static game_params *default_params(void)
ret->diff = DIFF_EASY;
ret->type = 0;
ret->game_grid = NULL;
return ret;
}
@ -490,44 +483,45 @@ static game_params *dup_params(game_params *params)
game_params *ret = snew(game_params);
*ret = *params; /* structure copy */
if (ret->game_grid) {
ret->game_grid->refcount++;
}
return ret;
}
static const game_params presets[] = {
#ifdef SMALL_SCREEN
{ 7, 7, DIFF_EASY, 0, NULL },
{ 7, 7, DIFF_NORMAL, 0, NULL },
{ 7, 7, DIFF_HARD, 0, NULL },
{ 7, 7, DIFF_HARD, 1, NULL },
{ 7, 7, DIFF_HARD, 2, NULL },
{ 5, 5, DIFF_HARD, 3, NULL },
{ 7, 7, DIFF_HARD, 4, NULL },
{ 5, 4, DIFF_HARD, 5, NULL },
{ 5, 5, DIFF_HARD, 6, NULL },
{ 5, 5, DIFF_HARD, 7, NULL },
{ 3, 3, DIFF_HARD, 8, NULL },
{ 3, 3, DIFF_HARD, 9, NULL },
{ 3, 3, DIFF_HARD, 10, NULL },
{ 7, 7, DIFF_EASY, 0 },
{ 7, 7, DIFF_NORMAL, 0 },
{ 7, 7, DIFF_HARD, 0 },
{ 7, 7, DIFF_HARD, 1 },
{ 7, 7, DIFF_HARD, 2 },
{ 5, 5, DIFF_HARD, 3 },
{ 7, 7, DIFF_HARD, 4 },
{ 5, 4, DIFF_HARD, 5 },
{ 5, 5, DIFF_HARD, 6 },
{ 5, 5, DIFF_HARD, 7 },
{ 3, 3, DIFF_HARD, 8 },
{ 3, 3, DIFF_HARD, 9 },
{ 3, 3, DIFF_HARD, 10 },
{ 6, 6, DIFF_HARD, 11 },
{ 6, 6, DIFF_HARD, 12 },
#else
{ 7, 7, DIFF_EASY, 0, NULL },
{ 10, 10, DIFF_EASY, 0, NULL },
{ 7, 7, DIFF_NORMAL, 0, NULL },
{ 10, 10, DIFF_NORMAL, 0, NULL },
{ 7, 7, DIFF_HARD, 0, NULL },
{ 10, 10, DIFF_HARD, 0, NULL },
{ 10, 10, DIFF_HARD, 1, NULL },
{ 12, 10, DIFF_HARD, 2, NULL },
{ 7, 7, DIFF_HARD, 3, NULL },
{ 9, 9, DIFF_HARD, 4, NULL },
{ 5, 4, DIFF_HARD, 5, NULL },
{ 7, 7, DIFF_HARD, 6, NULL },
{ 5, 5, DIFF_HARD, 7, NULL },
{ 5, 5, DIFF_HARD, 8, NULL },
{ 5, 4, DIFF_HARD, 9, NULL },
{ 5, 4, DIFF_HARD, 10, NULL },
{ 7, 7, DIFF_EASY, 0 },
{ 10, 10, DIFF_EASY, 0 },
{ 7, 7, DIFF_NORMAL, 0 },
{ 10, 10, DIFF_NORMAL, 0 },
{ 7, 7, DIFF_HARD, 0 },
{ 10, 10, DIFF_HARD, 0 },
{ 10, 10, DIFF_HARD, 1 },
{ 12, 10, DIFF_HARD, 2 },
{ 7, 7, DIFF_HARD, 3 },
{ 9, 9, DIFF_HARD, 4 },
{ 5, 4, DIFF_HARD, 5 },
{ 7, 7, DIFF_HARD, 6 },
{ 5, 5, DIFF_HARD, 7 },
{ 5, 5, DIFF_HARD, 8 },
{ 5, 4, DIFF_HARD, 9 },
{ 5, 4, DIFF_HARD, 10 },
{ 10, 10, DIFF_HARD, 11 },
{ 10, 10, DIFF_HARD, 12 }
#endif
};
@ -551,18 +545,11 @@ static int game_fetch_preset(int i, char **name, game_params **params)
static void free_params(game_params *params)
{
if (params->game_grid) {
grid_free(params->game_grid);
}
sfree(params);
}
static void decode_params(game_params *params, char const *string)
{
if (params->game_grid) {
grid_free(params->game_grid);
params->game_grid = NULL;
}
params->h = params->w = atoi(string);
params->diff = DIFF_EASY;
while (*string && isdigit((unsigned char)*string)) string++;
@ -641,7 +628,6 @@ static game_params *custom_params(config_item *cfg)
ret->type = cfg[2].ival;
ret->diff = cfg[3].ival;
ret->game_grid = NULL;
return ret;
}
@ -702,14 +688,44 @@ static char *state_to_text(const game_state *state)
return retval;
}
#define GRID_DESC_SEP '_'
/* Splits up a (optional) grid_desc from the game desc. Returns the
* grid_desc (which needs freeing) and updates the desc pointer to
* start of real desc, or returns NULL if no desc. */
static char *extract_grid_desc(char **desc)
{
char *sep = strchr(*desc, GRID_DESC_SEP), *gd;
int gd_len;
if (!sep) return NULL;
gd_len = sep - (*desc);
gd = snewn(gd_len+1, char);
memcpy(gd, *desc, gd_len);
gd[gd_len] = '\0';
*desc = sep+1;
return gd;
}
/* We require that the params pass the test in validate_params and that the
* description fills the entire game area */
static char *validate_desc(game_params *params, char *desc)
{
int count = 0;
grid *g;
params_generate_grid(params);
g = params->game_grid;
char *grid_desc, *ret;
/* It's pretty inefficient to do this just for validation. All we need to
* know is the precise number of faces. */
grid_desc = extract_grid_desc(&desc);
ret = grid_validate_desc(grid_types[params->type], params->w, params->h, grid_desc);
if (ret) return ret;
g = loopy_generate_grid(params, grid_desc);
if (grid_desc) sfree(grid_desc);
for (; *desc; ++desc) {
if ((*desc >= '0' && *desc <= '9') || (*desc >= 'A' && *desc <= 'Z')) {
@ -728,6 +744,8 @@ static char *validate_desc(game_params *params, char *desc)
if (count > g->num_faces)
return "Description too long for board size";
grid_free(g);
return NULL;
}
@ -809,16 +827,15 @@ static void game_changed_state(game_ui *ui, game_state *oldstate,
static void game_compute_size(game_params *params, int tilesize,
int *x, int *y)
{
grid *g;
int grid_width, grid_height, rendered_width, rendered_height;
int g_tilesize;
grid_compute_size(grid_types[params->type], params->w, params->h,
&g_tilesize, &grid_width, &grid_height);
params_generate_grid(params);
g = params->game_grid;
grid_width = g->highest_x - g->lowest_x;
grid_height = g->highest_y - g->lowest_y;
/* multiply first to minimise rounding error on integer division */
rendered_width = grid_width * tilesize / g->tilesize;
rendered_height = grid_height * tilesize / g->tilesize;
rendered_width = grid_width * tilesize / g_tilesize;
rendered_height = grid_height * tilesize / g_tilesize;
*x = rendered_width + 2 * BORDER(tilesize) + 1;
*y = rendered_height + 2 * BORDER(tilesize) + 1;
}
@ -1836,13 +1853,14 @@ static char *new_game_desc(game_params *params, random_state *rs,
char **aux, int interactive)
{
/* solution and description both use run-length encoding in obvious ways */
char *retval;
char *retval, *game_desc, *grid_desc;
grid *g;
game_state *state = snew(game_state);
game_state *state_new;
params_generate_grid(params);
state->game_grid = g = params->game_grid;
g->refcount++;
grid_desc = grid_new_desc(grid_types[params->type], params->w, params->h, rs);
state->game_grid = g = loopy_generate_grid(params, grid_desc);
state->clues = snewn(g->num_faces, signed char);
state->lines = snewn(g->num_edges, char);
state->line_errors = snewn(g->num_edges, unsigned char);
@ -1875,10 +1893,19 @@ static char *new_game_desc(game_params *params, random_state *rs,
goto newboard_please;
}
retval = state_to_text(state);
game_desc = state_to_text(state);
free_game(state);
if (grid_desc) {
retval = snewn(strlen(grid_desc) + 1 + strlen(game_desc) + 1, char);
sprintf(retval, "%s%c%s", grid_desc, GRID_DESC_SEP, game_desc);
sfree(grid_desc);
sfree(game_desc);
} else {
retval = game_desc;
}
assert(!validate_desc(params, retval));
return retval;
@ -1890,13 +1917,17 @@ static game_state *new_game(midend *me, game_params *params, char *desc)
game_state *state = snew(game_state);
int empties_to_make = 0;
int n,n2;
const char *dp = desc;
const char *dp;
char *grid_desc;
grid *g;
int num_faces, num_edges;
params_generate_grid(params);
state->game_grid = g = params->game_grid;
g->refcount++;
grid_desc = extract_grid_desc(&desc);
state->game_grid = g = loopy_generate_grid(params, grid_desc);
if (grid_desc) sfree(grid_desc);
dp = desc;
num_faces = g->num_faces;
num_edges = g->num_edges;
@ -4017,3 +4048,5 @@ int main(int argc, char **argv)
}
#endif
/* vim: set shiftwidth=4 tabstop=8: */

626
penrose.c Normal file
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@ -0,0 +1,626 @@
/* penrose.c
*
* Penrose tile generator.
*
* Uses half-tile technique outlined on:
*
* http://tartarus.org/simon/20110412-penrose/penrose.xhtml
*/
#include <assert.h>
#include <string.h>
#include <math.h>
#include <stdio.h>
#include "puzzles.h" /* for malloc routines, and PI */
#include "penrose.h"
/* -------------------------------------------------------
* 36-degree basis vector arithmetic routines.
*/
/* Imagine drawing a
* ten-point 'clock face' like this:
*
* -E
* -D | A
* \ | /
* -C. \ | / ,B
* `-._\|/_,-'
* ,-' /|\ `-.
* -B' / | \ `C
* / | \
* -A | D
* E
*
* In case the ASCII art isn't clear, those are supposed to be ten
* vectors of length 1, all sticking out from the origin at equal
* angular spacing (hence 36 degrees). Our basis vectors are A,B,C,D (I
* choose them to be symmetric about the x-axis so that the final
* translation into 2d coordinates will also be symmetric, which I
* think will avoid minor rounding uglinesses), so our vector
* representation sets
*
* A = (1,0,0,0)
* B = (0,1,0,0)
* C = (0,0,1,0)
* D = (0,0,0,1)
*
* The fifth vector E looks at first glance as if it needs to be
* another basis vector, but in fact it doesn't, because it can be
* represented in terms of the other four. Imagine starting from the
* origin and following the path -A, +B, -C, +D: you'll find you've
* traced four sides of a pentagram, and ended up one E-vector away
* from the origin. So we have
*
* E = (-1,1,-1,1)
*
* This tells us that we can rotate any vector in this system by 36
* degrees: if we start with a*A + b*B + c*C + d*D, we want to end up
* with a*B + b*C + c*D + d*E, and we substitute our identity for E to
* turn that into a*B + b*C + c*D + d*(-A+B-C+D). In other words,
*
* rotate_one_notch_clockwise(a,b,c,d) = (-d, d+a, -d+b, d+c)
*
* and you can verify for yourself that applying that operation
* repeatedly starting with (1,0,0,0) cycles round ten vectors and
* comes back to where it started.
*
* The other operation that may be required is to construct vectors
* with lengths that are multiples of phi. That can be done by
* observing that the vector C-B is parallel to E and has length 1/phi,
* and the vector D-A is parallel to E and has length phi. So this
* tells us that given any vector, we can construct one which points in
* the same direction and is 1/phi or phi times its length, like this:
*
* divide_by_phi(vector) = rotate(vector, 2) - rotate(vector, 3)
* multiply_by_phi(vector) = rotate(vector, 1) - rotate(vector, 4)
*
* where rotate(vector, n) means applying the above
* rotate_one_notch_clockwise primitive n times. Expanding out the
* applications of rotate gives the following direct representation in
* terms of the vector coordinates:
*
* divide_by_phi(a,b,c,d) = (b-d, c+d-b, a+b-c, c-a)
* multiply_by_phi(a,b,c,d) = (a+b-d, c+d, a+b, c+d-a)
*
* and you can verify for yourself that those two operations are
* inverses of each other (as you'd hope!).
*
* Having done all of this, testing for equality between two vectors is
* a trivial matter of comparing the four integer coordinates. (Which
* it _wouldn't_ have been if we'd kept E as a fifth basis vector,
* because then (-1,1,-1,1,0) and (0,0,0,0,1) would have had to be
* considered identical. So leaving E out is vital.)
*/
struct vector { int a, b, c, d; };
static vector v_origin()
{
vector v;
v.a = v.b = v.c = v.d = 0;
return v;
}
/* We start with a unit vector of B: this means we can easily
* draw an isoceles triangle centred on the X axis. */
#ifdef TEST_VECTORS
static vector v_unit()
{
vector v;
v.b = 1;
v.a = v.c = v.d = 0;
return v;
}
#endif
#define COS54 0.5877852
#define SIN54 0.8090169
#define COS18 0.9510565
#define SIN18 0.3090169
/* These two are a bit rough-and-ready for now. Note that B/C are
* 18 degrees from the x-axis, and A/D are 54 degrees. */
double v_x(vector *vs, int i)
{
return (vs[i].a + vs[i].d) * COS54 +
(vs[i].b + vs[i].c) * COS18;
}
double v_y(vector *vs, int i)
{
return (vs[i].a - vs[i].d) * SIN54 +
(vs[i].b - vs[i].c) * SIN18;
}
static vector v_trans(vector v, vector trans)
{
v.a += trans.a;
v.b += trans.b;
v.c += trans.c;
v.d += trans.d;
return v;
}
static vector v_rotate_36(vector v)
{
vector vv;
vv.a = -v.d;
vv.b = v.d + v.a;
vv.c = -v.d + v.b;
vv.d = v.d + v.c;
return vv;
}
static vector v_rotate(vector v, int ang)
{
int i;
assert((ang % 36) == 0);
while (ang < 0) ang += 360;
ang = 360-ang;
for (i = 0; i < (ang/36); i++)
v = v_rotate_36(v);
return v;
}
#ifdef TEST_VECTORS
static vector v_scale(vector v, int sc)
{
v.a *= sc;
v.b *= sc;
v.c *= sc;
v.d *= sc;
return v;
}
#endif
static vector v_growphi(vector v)
{
vector vv;
vv.a = v.a + v.b - v.d;
vv.b = v.c + v.d;
vv.c = v.a + v.b;
vv.d = v.c + v.d - v.a;
return vv;
}
static vector v_shrinkphi(vector v)
{
vector vv;
vv.a = v.b - v.d;
vv.b = v.c + v.d - v.b;
vv.c = v.a + v.b - v.c;
vv.d = v.c - v.a;
return vv;
}
#ifdef TEST_VECTORS
static const char *v_debug(vector v)
{
static char buf[255];
sprintf(buf,
"(%d,%d,%d,%d)[%2.2f,%2.2f]",
v.a, v.b, v.c, v.d, v_x(&v,0), v_y(&v,0));
return buf;
}
#endif
/* -------------------------------------------------------
* Tiling routines.
*/
vector xform_coord(vector vo, int shrink, vector vtrans, int ang)
{
if (shrink < 0)
vo = v_shrinkphi(vo);
else if (shrink > 0)
vo = v_growphi(vo);
vo = v_rotate(vo, ang);
vo = v_trans(vo, vtrans);
return vo;
}
#define XFORM(n,o,s,a) vs[(n)] = xform_coord(v_edge, (s), vs[(o)], (a))
static int penrose_p2_small(penrose_state *state, int depth, int flip,
vector v_orig, vector v_edge);
static int penrose_p2_large(penrose_state *state, int depth, int flip,
vector v_orig, vector v_edge)
{
vector vv_orig, vv_edge;
#ifdef DEBUG_PENROSE
{
vector vs[3];
vs[0] = v_orig;
XFORM(1, 0, 0, 0);
XFORM(2, 0, 0, -36*flip);
state->new_tile(state, vs, 3, depth);
}
#endif
if (flip > 0) {
vector vs[4];
vs[0] = v_orig;
XFORM(1, 0, 0, -36);
XFORM(2, 0, 0, 0);
XFORM(3, 0, 0, 36);
state->new_tile(state, vs, 4, depth);
}
if (depth >= state->max_depth) return 0;
vv_orig = v_trans(v_orig, v_rotate(v_edge, -36*flip));
vv_edge = v_rotate(v_edge, 108*flip);
penrose_p2_small(state, depth+1, flip,
v_orig, v_shrinkphi(v_edge));
penrose_p2_large(state, depth+1, flip,
vv_orig, v_shrinkphi(vv_edge));
penrose_p2_large(state, depth+1, -flip,
vv_orig, v_shrinkphi(vv_edge));
return 0;
}
static int penrose_p2_small(penrose_state *state, int depth, int flip,
vector v_orig, vector v_edge)
{
vector vv_orig;
#ifdef DEBUG_PENROSE
{
vector vs[3];
vs[0] = v_orig;
XFORM(1, 0, 0, 0);
XFORM(2, 0, -1, -36*flip);
state->new_tile(state, vs, 3, depth);
}
#endif
if (flip > 0) {
vector vs[4];
vs[0] = v_orig;
XFORM(1, 0, 0, -72);
XFORM(2, 0, -1, -36);
XFORM(3, 0, 0, 0);
state->new_tile(state, vs, 4, depth);
}
if (depth >= state->max_depth) return 0;
vv_orig = v_trans(v_orig, v_edge);
penrose_p2_large(state, depth+1, -flip,
v_orig, v_shrinkphi(v_rotate(v_edge, -36*flip)));
penrose_p2_small(state, depth+1, flip,
vv_orig, v_shrinkphi(v_rotate(v_edge, -144*flip)));
return 0;
}
static int penrose_p3_small(penrose_state *state, int depth, int flip,
vector v_orig, vector v_edge);
static int penrose_p3_large(penrose_state *state, int depth, int flip,
vector v_orig, vector v_edge)
{
vector vv_orig;
#ifdef DEBUG_PENROSE
{
vector vs[3];
vs[0] = v_orig;
XFORM(1, 0, 1, 0);
XFORM(2, 0, 0, -36*flip);
state->new_tile(state, vs, 3, depth);
}
#endif
if (flip > 0) {
vector vs[4];
vs[0] = v_orig;
XFORM(1, 0, 0, -36);
XFORM(2, 0, 1, 0);
XFORM(3, 0, 0, 36);
state->new_tile(state, vs, 4, depth);
}
if (depth >= state->max_depth) return 0;
vv_orig = v_trans(v_orig, v_edge);
penrose_p3_large(state, depth+1, -flip,
vv_orig, v_shrinkphi(v_rotate(v_edge, 180)));
penrose_p3_small(state, depth+1, flip,
vv_orig, v_shrinkphi(v_rotate(v_edge, -108*flip)));
vv_orig = v_trans(v_orig, v_growphi(v_edge));
penrose_p3_large(state, depth+1, flip,
vv_orig, v_shrinkphi(v_rotate(v_edge, -144*flip)));
return 0;
}
static int penrose_p3_small(penrose_state *state, int depth, int flip,
vector v_orig, vector v_edge)
{
vector vv_orig;
#ifdef DEBUG_PENROSE
{
vector vs[3];
vs[0] = v_orig;
XFORM(1, 0, 0, 0);
XFORM(2, 0, 0, -36*flip);
state->new_tile(state, vs, 3, depth);
}
#endif
if (flip > 0) {
vector vs[4];
vs[0] = v_orig;
XFORM(1, 0, 0, -36);
XFORM(3, 0, 0, 0);
XFORM(2, 3, 0, -36);
state->new_tile(state, vs, 4, depth);
}
if (depth >= state->max_depth) return 0;
/* NB these two are identical to the first two of p3_large. */
vv_orig = v_trans(v_orig, v_edge);
penrose_p3_large(state, depth+1, -flip,
vv_orig, v_shrinkphi(v_rotate(v_edge, 180)));
penrose_p3_small(state, depth+1, flip,
vv_orig, v_shrinkphi(v_rotate(v_edge, -108*flip)));
return 0;
}
/* -------------------------------------------------------
* Utility routines.
*/
double penrose_side_length(double start_size, int depth)
{
return start_size / pow(PHI, depth);
}
void penrose_count_tiles(int depth, int *nlarge, int *nsmall)
{
/* Steal sgt's fibonacci thingummy. */
}
/*
* It turns out that an acute isosceles triangle with sides in ratio 1:phi:phi
* has an incentre which is conveniently 2*phi^-2 of the way from the apex to
* the base. Why's that convenient? Because: if we situate the incentre of the
* triangle at the origin, then we can place the apex at phi^-2 * (B+C), and
* the other two vertices at apex-B and apex-C respectively. So that's an acute
* triangle with its long sides of unit length, covering a circle about the
* origin of radius 1-(2*phi^-2), which is conveniently enough phi^-3.
*
* (later mail: this is an overestimate by about 5%)
*/
int penrose(penrose_state *state, int which)
{
vector vo = v_origin();
vector vb = v_origin();
vo.b = vo.c = -state->start_size;
vo = v_shrinkphi(v_shrinkphi(vo));
vb.b = state->start_size;
if (which == PENROSE_P2)
return penrose_p2_large(state, 0, 1, vo, vb);
else
return penrose_p3_small(state, 0, 1, vo, vb);
}
/*
* We're asked for a MxN grid, which just means a tiling fitting into roughly
* an MxN space in some kind of reasonable unit - say, the side length of the
* two-arrow edges of the tiles. By some reasoning in a previous email, that
* means we want to pick some subarea of a circle of radius 3.11*sqrt(M^2+N^2).
* To cover that circle, we need to subdivide a triangle large enough that it
* contains a circle of that radius.
*
* Hence: start with those three vectors marking triangle vertices, scale them
* all up by phi repeatedly until the radius of the inscribed circle gets
* bigger than the target, and then recurse into that triangle with the same
* recursion depth as the number of times you scaled up. That will give you
* tiles of unit side length, covering a circle big enough that if you randomly
* choose an orientation and coordinates within the circle, you'll be able to
* get any valid piece of Penrose tiling of size MxN.
*/
#define INCIRCLE_RADIUS 0.22426 /* phi^-3 less 5%: see above */
void penrose_calculate_size(int which, int tilesize, int w, int h,
double *required_radius, int *start_size, int *depth)
{
double rradius, size;
int n = 0;
/*
* Fudge factor to scale P2 and P3 tilings differently. This
* doesn't seem to have much relevance to questions like the
* average number of tiles per unit area; it's just aesthetic.
*/
if (which == PENROSE_P2)
tilesize = tilesize * 3 / 2;
else
tilesize = tilesize * 5 / 4;
rradius = tilesize * 3.11 * sqrt((double)(w*w + h*h));
size = tilesize;
while ((size * INCIRCLE_RADIUS) < rradius) {
n++;
size = size * PHI;
}
*start_size = (int)size;
*depth = n;
*required_radius = rradius;
}
/* -------------------------------------------------------
* Test code.
*/
#ifdef TEST_PENROSE
#include <stdio.h>
#include <string.h>
int show_recursion = 0;
int ntiles, nfinal;
int test_cb(penrose_state *state, vector *vs, int n, int depth)
{
int i, xoff = 0, yoff = 0;
double l = penrose_side_length(state->start_size, depth);
double rball = l / 10.0;
const char *col;
ntiles++;
if (state->max_depth == depth) {
col = n == 4 ? "black" : "green";
nfinal++;
} else {
if (!show_recursion)
return 0;
col = n == 4 ? "red" : "blue";
}
if (n != 4) yoff = state->start_size;
printf("<polygon points=\"");
for (i = 0; i < n; i++) {
printf("%s%f,%f", (i == 0) ? "" : " ",
v_x(vs, i) + xoff, v_y(vs, i) + yoff);
}
printf("\" style=\"fill: %s; fill-opacity: 0.2; stroke: %s\" />\n", col, col);
printf("<ellipse cx=\"%f\" cy=\"%f\" rx=\"%f\" ry=\"%f\" fill=\"%s\" />",
v_x(vs, 0) + xoff, v_y(vs, 0) + yoff, rball, rball, col);
return 0;
}
void usage_exit()
{
fprintf(stderr, "Usage: penrose-test [--recursion] P2|P3 SIZE DEPTH\n");
exit(1);
}
int main(int argc, char *argv[])
{
penrose_state ps;
int which = 0;
while (--argc > 0) {
char *p = *++argv;
if (!strcmp(p, "-h") || !strcmp(p, "--help")) {
usage_exit();
} else if (!strcmp(p, "--recursion")) {
show_recursion = 1;
} else if (*p == '-') {
fprintf(stderr, "Unrecognised option '%s'\n", p);
exit(1);
} else {
break;
}
}
if (argc < 3) usage_exit();
if (strcmp(argv[0], "P2") == 0) which = PENROSE_P2;
else if (strcmp(argv[0], "P3") == 0) which = PENROSE_P3;
else usage_exit();
ps.start_size = atoi(argv[1]);
ps.max_depth = atoi(argv[2]);
ps.new_tile = test_cb;
ntiles = nfinal = 0;
printf("\
<?xml version=\"1.0\" encoding=\"UTF-8\" standalone=\"no\"?>\n\
<!DOCTYPE svg PUBLIC \"-//W3C//DTD SVG 20010904//EN\"\n\
\"http://www.w3.org/TR/2001/REC-SVG-20010904/DTD/svg10.dtd\">\n\
\n\
<svg xmlns=\"http://www.w3.org/2000/svg\"\n\
xmlns:xlink=\"http://www.w3.org/1999/xlink\">\n\n");
printf("<g>\n");
penrose(&ps, which);
printf("</g>\n");
printf("<!-- %d tiles and %d leaf tiles total -->\n",
ntiles, nfinal);
printf("</svg>");
return 0;
}
#endif
#ifdef TEST_VECTORS
static void dbgv(const char *msg, vector v)
{
printf("%s: %s\n", msg, v_debug(v));
}
int main(int argc, const char *argv[])
{
vector v = v_unit();
dbgv("unit vector", v);
v = v_rotate(v, 36);
dbgv("rotated 36", v);
v = v_scale(v, 2);
dbgv("scaled x2", v);
v = v_shrinkphi(v);
dbgv("shrunk phi", v);
v = v_rotate(v, -36);
dbgv("rotated -36", v);
return 0;
}
#endif
/* vim: set shiftwidth=4 tabstop=8: */

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/* penrose.h
*
* Penrose tiling functions.
*
* Provides an interface with which to generate Penrose tilings
* by recursive subdivision of an initial tile of choice (one of the
* four sets of two pairs kite/dart, or thin/thick rhombus).
*
* You supply a callback function and a context pointer, which is
* called with each tile in turn: you choose how many times to recurse.
*/
#ifndef _PENROSE_H
#define _PENROSE_H
#ifndef PHI
#define PHI 1.6180339887
#endif
typedef struct vector vector;
double v_x(vector *vs, int i);
double v_y(vector *vs, int i);
typedef struct penrose_state penrose_state;
/* Return non-zero to clip the tree here (i.e. not recurse
* below this tile).
*
* Parameters are state, vector array, npoints, depth.
* ctx is inside state.
*/
typedef int (*tile_callback)(penrose_state *, vector *, int, int);
struct penrose_state {
int start_size; /* initial side length */
int max_depth; /* Recursion depth */
tile_callback new_tile;
void *ctx; /* for callback */
};
enum { PENROSE_P2, PENROSE_P3 };
extern int penrose(penrose_state *state, int which);
/* Returns the side-length of a penrose tile at recursion level
* gen, given a starting side length. */
extern double penrose_side_length(double start_size, int depth);
/* Returns the count of each type of tile at a given recursion depth. */
extern void penrose_count_tiles(int gen, int *nlarge, int *nsmall);
/* Calculate start size and recursion depth required to produce a
* width-by-height sized patch of penrose tiles with the given tilesize */
extern void penrose_calculate_size(int which, int tilesize, int w, int h,
double *required_radius, int *start_size, int *depth);
#endif