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puzzles/slant.c
Simon Tatham 7b1f7d3e01 HTML Help support for Puzzles, with the same kind of automatic 
fallback behaviour as PuTTY's support.

[originally from svn r7009]
2006-12-24 15:56:47 +00:00

2314 lines
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/*
* slant.c: Puzzle from nikoli.co.jp involving drawing a diagonal
* line through each square of a grid.
*/
/*
* In this puzzle you have a grid of squares, each of which must
* contain a diagonal line; you also have clue numbers placed at
* _points_ of that grid, which means there's a (w+1) x (h+1) array
* of possible clue positions.
*
* I'm therefore going to adopt a rigid convention throughout this
* source file of using w and h for the dimensions of the grid of
* squares, and W and H for the dimensions of the grid of points.
* Thus, W == w+1 and H == h+1 always.
*
* Clue arrays will be W*H `signed char's, and the clue at each
* point will be a number from 0 to 4, or -1 if there's no clue.
*
* Solution arrays will be W*H `signed char's, and the number at
* each point will be +1 for a forward slash (/), -1 for a
* backslash (\), and 0 for unknown.
*/
#include <stdio.h>
#include <stdlib.h>
#include <stdarg.h>
#include <string.h>
#include <assert.h>
#include <ctype.h>
#include <math.h>
#include "puzzles.h"
enum {
COL_BACKGROUND,
COL_GRID,
COL_INK,
COL_SLANT1,
COL_SLANT2,
COL_ERROR,
NCOLOURS
};
/*
* In standalone solver mode, `verbose' is a variable which can be
* set by command-line option; in debugging mode it's simply always
* true.
*/
#if defined STANDALONE_SOLVER
#define SOLVER_DIAGNOSTICS
int verbose = FALSE;
#elif defined SOLVER_DIAGNOSTICS
#define verbose TRUE
#endif
/*
* Difficulty levels. I do some macro ickery here to ensure that my
* enum and the various forms of my name list always match up.
*/
#define DIFFLIST(A) \
A(EASY,Easy,e) \
A(HARD,Hard,h)
#define ENUM(upper,title,lower) DIFF_ ## upper,
#define TITLE(upper,title,lower) #title,
#define ENCODE(upper,title,lower) #lower
#define CONFIG(upper,title,lower) ":" #title
enum { DIFFLIST(ENUM) DIFFCOUNT };
static char const *const slant_diffnames[] = { DIFFLIST(TITLE) };
static char const slant_diffchars[] = DIFFLIST(ENCODE);
#define DIFFCONFIG DIFFLIST(CONFIG)
struct game_params {
int w, h, diff;
};
typedef struct game_clues {
int w, h;
signed char *clues;
int *tmpdsf;
int refcount;
} game_clues;
#define ERR_VERTEX 1
#define ERR_SQUARE 2
#define ERR_SQUARE_TMP 4
struct game_state {
struct game_params p;
game_clues *clues;
signed char *soln;
unsigned char *errors;
int completed;
int used_solve; /* used to suppress completion flash */
};
static game_params *default_params(void)
{
game_params *ret = snew(game_params);
ret->w = ret->h = 8;
ret->diff = DIFF_EASY;
return ret;
}
static const struct game_params slant_presets[] = {
{5, 5, DIFF_EASY},
{5, 5, DIFF_HARD},
{8, 8, DIFF_EASY},
{8, 8, DIFF_HARD},
{12, 10, DIFF_EASY},
{12, 10, DIFF_HARD},
};
static int game_fetch_preset(int i, char **name, game_params **params)
{
game_params *ret;
char str[80];
if (i < 0 || i >= lenof(slant_presets))
return FALSE;
ret = snew(game_params);
*ret = slant_presets[i];
sprintf(str, "%dx%d %s", ret->w, ret->h, slant_diffnames[ret->diff]);
*name = dupstr(str);
*params = ret;
return TRUE;
}
static void free_params(game_params *params)
{
sfree(params);
}
static game_params *dup_params(game_params *params)
{
game_params *ret = snew(game_params);
*ret = *params; /* structure copy */
return ret;
}
static void decode_params(game_params *ret, char const *string)
{
ret->w = ret->h = atoi(string);
while (*string && isdigit((unsigned char)*string)) string++;
if (*string == 'x') {
string++;
ret->h = atoi(string);
while (*string && isdigit((unsigned char)*string)) string++;
}
if (*string == 'd') {
int i;
string++;
for (i = 0; i < DIFFCOUNT; i++)
if (*string == slant_diffchars[i])
ret->diff = i;
if (*string) string++;
}
}
static char *encode_params(game_params *params, int full)
{
char data[256];
sprintf(data, "%dx%d", params->w, params->h);
if (full)
sprintf(data + strlen(data), "d%c", slant_diffchars[params->diff]);
return dupstr(data);
}
static config_item *game_configure(game_params *params)
{
config_item *ret;
char buf[80];
ret = snewn(4, config_item);
ret[0].name = "Width";
ret[0].type = C_STRING;
sprintf(buf, "%d", params->w);
ret[0].sval = dupstr(buf);
ret[0].ival = 0;
ret[1].name = "Height";
ret[1].type = C_STRING;
sprintf(buf, "%d", params->h);
ret[1].sval = dupstr(buf);
ret[1].ival = 0;
ret[2].name = "Difficulty";
ret[2].type = C_CHOICES;
ret[2].sval = DIFFCONFIG;
ret[2].ival = params->diff;
ret[3].name = NULL;
ret[3].type = C_END;
ret[3].sval = NULL;
ret[3].ival = 0;
return ret;
}
static game_params *custom_params(config_item *cfg)
{
game_params *ret = snew(game_params);
ret->w = atoi(cfg[0].sval);
ret->h = atoi(cfg[1].sval);
ret->diff = cfg[2].ival;
return ret;
}
static char *validate_params(game_params *params, int full)
{
/*
* (At least at the time of writing this comment) The grid
* generator is actually capable of handling even zero grid
* dimensions without crashing. Puzzles with a zero-area grid
* are a bit boring, though, because they're already solved :-)
* And puzzles with a dimension of 1 can't be made Hard, which
* means the simplest thing is to forbid them altogether.
*/
if (params->w < 2 || params->h < 2)
return "Width and height must both be at least two";
return NULL;
}
/*
* Scratch space for solver.
*/
struct solver_scratch {
/*
* Disjoint set forest which tracks the connected sets of
* points.
*/
int *connected;
/*
* Counts the number of possible exits from each connected set
* of points. (That is, the number of possible _simultaneous_
* exits: an unconnected point labelled 2 has an exit count of
* 2 even if all four possible edges are still under
* consideration.)
*/
int *exits;
/*
* Tracks whether each connected set of points includes a
* border point.
*/
unsigned char *border;
/*
* Another disjoint set forest. This one tracks _squares_ which
* are known to slant in the same direction.
*/
int *equiv;
/*
* Stores slash values which we know for an equivalence class.
* When we fill in a square, we set slashval[canonify(x)] to
* the same value as soln[x], so that we can then spot other
* squares equivalent to it and fill them in immediately via
* their known equivalence.
*/
signed char *slashval;
/*
* Stores possible v-shapes. This array is w by h in size, but
* not every bit of every entry is meaningful. The bits mean:
*
* - bit 0 for a square means that that square and the one to
* its right might form a v-shape between them
* - bit 1 for a square means that that square and the one to
* its right might form a ^-shape between them
* - bit 2 for a square means that that square and the one
* below it might form a >-shape between them
* - bit 3 for a square means that that square and the one
* below it might form a <-shape between them
*
* Any starting 1 or 3 clue rules out four bits in this array
* immediately; a 2 clue propagates any ruled-out bit past it
* (if the two squares on one side of a 2 cannot be a v-shape,
* then neither can the two on the other side be the same
* v-shape); we can rule out further bits during play using
* partially filled 2 clues; whenever a pair of squares is
* known not to be _either_ kind of v-shape, we can mark them
* as equivalent.
*/
unsigned char *vbitmap;
/*
* Useful to have this information automatically passed to
* solver subroutines. (This pointer is not dynamically
* allocated by new_scratch and free_scratch.)
*/
const signed char *clues;
};
static struct solver_scratch *new_scratch(int w, int h)
{
int W = w+1, H = h+1;
struct solver_scratch *ret = snew(struct solver_scratch);
ret->connected = snewn(W*H, int);
ret->exits = snewn(W*H, int);
ret->border = snewn(W*H, unsigned char);
ret->equiv = snewn(w*h, int);
ret->slashval = snewn(w*h, signed char);
ret->vbitmap = snewn(w*h, unsigned char);
return ret;
}
static void free_scratch(struct solver_scratch *sc)
{
sfree(sc->vbitmap);
sfree(sc->slashval);
sfree(sc->equiv);
sfree(sc->border);
sfree(sc->exits);
sfree(sc->connected);
sfree(sc);
}
/*
* Wrapper on dsf_merge() which updates the `exits' and `border'
* arrays.
*/
static void merge_vertices(int *connected,
struct solver_scratch *sc, int i, int j)
{
int exits = -1, border = FALSE; /* initialise to placate optimiser */
if (sc) {
i = dsf_canonify(connected, i);
j = dsf_canonify(connected, j);
/*
* We have used one possible exit from each of the two
* classes. Thus, the viable exit count of the new class is
* the sum of the old exit counts minus two.
*/
exits = sc->exits[i] + sc->exits[j] - 2;
border = sc->border[i] || sc->border[j];
}
dsf_merge(connected, i, j);
if (sc) {
i = dsf_canonify(connected, i);
sc->exits[i] = exits;
sc->border[i] = border;
}
}
/*
* Called when we have just blocked one way out of a particular
* point. If that point is a non-clue point (thus has a variable
* number of exits), we have therefore decreased its potential exit
* count, so we must decrement the exit count for the group as a
* whole.
*/
static void decr_exits(struct solver_scratch *sc, int i)
{
if (sc->clues[i] < 0) {
i = dsf_canonify(sc->connected, i);
sc->exits[i]--;
}
}
static void fill_square(int w, int h, int x, int y, int v,
signed char *soln,
int *connected, struct solver_scratch *sc)
{
int W = w+1 /*, H = h+1 */;
assert(x >= 0 && x < w && y >= 0 && y < h);
if (soln[y*w+x] != 0) {
return; /* do nothing */
}
#ifdef SOLVER_DIAGNOSTICS
if (verbose)
printf(" placing %c in %d,%d\n", v == -1 ? '\\' : '/', x, y);
#endif
soln[y*w+x] = v;
if (sc) {
int c = dsf_canonify(sc->equiv, y*w+x);
sc->slashval[c] = v;
}
if (v < 0) {
merge_vertices(connected, sc, y*W+x, (y+1)*W+(x+1));
if (sc) {
decr_exits(sc, y*W+(x+1));
decr_exits(sc, (y+1)*W+x);
}
} else {
merge_vertices(connected, sc, y*W+(x+1), (y+1)*W+x);
if (sc) {
decr_exits(sc, y*W+x);
decr_exits(sc, (y+1)*W+(x+1));
}
}
}
static int vbitmap_clear(int w, int h, struct solver_scratch *sc,
int x, int y, int vbits, char *reason, ...)
{
int done_something = FALSE;
int vbit;
for (vbit = 1; vbit <= 8; vbit <<= 1)
if (vbits & sc->vbitmap[y*w+x] & vbit) {
done_something = TRUE;
#ifdef SOLVER_DIAGNOSTICS
if (verbose) {
va_list ap;
printf("ruling out %c shape at (%d,%d)-(%d,%d) (",
"!v^!>!!!<"[vbit], x, y,
x+((vbit&0x3)!=0), y+((vbit&0xC)!=0));
va_start(ap, reason);
vprintf(reason, ap);
va_end(ap);
printf(")\n");
}
#endif
sc->vbitmap[y*w+x] &= ~vbit;
}
return done_something;
}
/*
* Solver. Returns 0 for impossibility, 1 for success, 2 for
* ambiguity or failure to converge.
*/
static int slant_solve(int w, int h, const signed char *clues,
signed char *soln, struct solver_scratch *sc,
int difficulty)
{
int W = w+1, H = h+1;
int x, y, i, j;
int done_something;
/*
* Clear the output.
*/
memset(soln, 0, w*h);
sc->clues = clues;
/*
* Establish a disjoint set forest for tracking connectedness
* between grid points.
*/
dsf_init(sc->connected, W*H);
/*
* Establish a disjoint set forest for tracking which squares
* are known to slant in the same direction.
*/
dsf_init(sc->equiv, w*h);
/*
* Clear the slashval array.
*/
memset(sc->slashval, 0, w*h);
/*
* Set up the vbitmap array. Initially all types of v are possible.
*/
memset(sc->vbitmap, 0xF, w*h);
/*
* Initialise the `exits' and `border' arrays. These are used
* to do second-order loop avoidance: the dual of the no loops
* constraint is that every point must be somehow connected to
* the border of the grid (otherwise there would be a solid
* loop around it which prevented this).
*
* I define a `dead end' to be a connected group of points
* which contains no border point, and which can form at most
* one new connection outside itself. Then I forbid placing an
* edge so that it connects together two dead-end groups, since
* this would yield a non-border-connected isolated subgraph
* with no further scope to extend it.
*/
for (y = 0; y < H; y++)
for (x = 0; x < W; x++) {
if (y == 0 || y == H-1 || x == 0 || x == W-1)
sc->border[y*W+x] = TRUE;
else
sc->border[y*W+x] = FALSE;
if (clues[y*W+x] < 0)
sc->exits[y*W+x] = 4;
else
sc->exits[y*W+x] = clues[y*W+x];
}
/*
* Repeatedly try to deduce something until we can't.
*/
do {
done_something = FALSE;
/*
* Any clue point with the number of remaining lines equal
* to zero or to the number of remaining undecided
* neighbouring squares can be filled in completely.
*/
for (y = 0; y < H; y++)
for (x = 0; x < W; x++) {
struct {
int pos, slash;
} neighbours[4];
int nneighbours;
int nu, nl, c, s, eq, eq2, last, meq, mj1, mj2;
if ((c = clues[y*W+x]) < 0)
continue;
/*
* We have a clue point. Start by listing its
* neighbouring squares, in order around the point,
* together with the type of slash that would be
* required in that square to connect to the point.
*/
nneighbours = 0;
if (x > 0 && y > 0) {
neighbours[nneighbours].pos = (y-1)*w+(x-1);
neighbours[nneighbours].slash = -1;
nneighbours++;
}
if (x > 0 && y < h) {
neighbours[nneighbours].pos = y*w+(x-1);
neighbours[nneighbours].slash = +1;
nneighbours++;
}
if (x < w && y < h) {
neighbours[nneighbours].pos = y*w+x;
neighbours[nneighbours].slash = -1;
nneighbours++;
}
if (x < w && y > 0) {
neighbours[nneighbours].pos = (y-1)*w+x;
neighbours[nneighbours].slash = +1;
nneighbours++;
}
/*
* Count up the number of undecided neighbours, and
* also the number of lines already present.
*
* If we're not on DIFF_EASY, then in this loop we
* also track whether we've seen two adjacent empty
* squares belonging to the same equivalence class
* (meaning they have the same type of slash). If
* so, we count them jointly as one line.
*/
nu = 0;
nl = c;
last = neighbours[nneighbours-1].pos;
if (soln[last] == 0)
eq = dsf_canonify(sc->equiv, last);
else
eq = -1;
meq = mj1 = mj2 = -1;
for (i = 0; i < nneighbours; i++) {
j = neighbours[i].pos;
s = neighbours[i].slash;
if (soln[j] == 0) {
nu++; /* undecided */
if (meq < 0 && difficulty > DIFF_EASY) {
eq2 = dsf_canonify(sc->equiv, j);
if (eq == eq2 && last != j) {
/*
* We've found an equivalent pair.
* Mark it. This also inhibits any
* further equivalence tracking
* around this square, since we can
* only handle one pair (and in
* particular we want to avoid
* being misled by two overlapping
* equivalence pairs).
*/
meq = eq;
mj1 = last;
mj2 = j;
nl--; /* count one line */
nu -= 2; /* and lose two undecideds */
} else
eq = eq2;
}
} else {
eq = -1;
if (soln[j] == s)
nl--; /* here's a line */
}
last = j;
}
/*
* Check the counts.
*/
if (nl < 0 || nl > nu) {
/*
* No consistent value for this at all!
*/
#ifdef SOLVER_DIAGNOSTICS
if (verbose)
printf("need %d / %d lines around clue point at %d,%d!\n",
nl, nu, x, y);
#endif
return 0; /* impossible */
}
if (nu > 0 && (nl == 0 || nl == nu)) {
#ifdef SOLVER_DIAGNOSTICS
if (verbose) {
if (meq >= 0)
printf("partially (since %d,%d == %d,%d) ",
mj1%w, mj1/w, mj2%w, mj2/w);
printf("%s around clue point at %d,%d\n",
nl ? "filling" : "emptying", x, y);
}
#endif
for (i = 0; i < nneighbours; i++) {
j = neighbours[i].pos;
s = neighbours[i].slash;
if (soln[j] == 0 && j != mj1 && j != mj2)
fill_square(w, h, j%w, j/w, (nl ? s : -s), soln,
sc->connected, sc);
}
done_something = TRUE;
} else if (nu == 2 && nl == 1 && difficulty > DIFF_EASY) {
/*
* If we have precisely two undecided squares
* and precisely one line to place between
* them, _and_ those squares are adjacent, then
* we can mark them as equivalent to one
* another.
*
* This even applies if meq >= 0: if we have a
* 2 clue point and two of its neighbours are
* already marked equivalent, we can indeed
* mark the other two as equivalent.
*
* We don't bother with this on DIFF_EASY,
* since we wouldn't have used the results
* anyway.
*/
last = -1;
for (i = 0; i < nneighbours; i++) {
j = neighbours[i].pos;
if (soln[j] == 0 && j != mj1 && j != mj2) {
if (last < 0)
last = i;
else if (last == i-1 || (last == 0 && i == 3))
break; /* found a pair */
}
}
if (i < nneighbours) {
int sv1, sv2;
assert(last >= 0);
/*
* neighbours[last] and neighbours[i] are
* the pair. Mark them equivalent.
*/
#ifdef SOLVER_DIAGNOSTICS
if (verbose) {
if (meq >= 0)
printf("since %d,%d == %d,%d, ",
mj1%w, mj1/w, mj2%w, mj2/w);
}
#endif
mj1 = neighbours[last].pos;
mj2 = neighbours[i].pos;
#ifdef SOLVER_DIAGNOSTICS
if (verbose)
printf("clue point at %d,%d implies %d,%d == %d,"
"%d\n", x, y, mj1%w, mj1/w, mj2%w, mj2/w);
#endif
mj1 = dsf_canonify(sc->equiv, mj1);
sv1 = sc->slashval[mj1];
mj2 = dsf_canonify(sc->equiv, mj2);
sv2 = sc->slashval[mj2];
if (sv1 != 0 && sv2 != 0 && sv1 != sv2) {
#ifdef SOLVER_DIAGNOSTICS
if (verbose)
printf("merged two equivalence classes with"
" different slash values!\n");
#endif
return 0;
}
sv1 = sv1 ? sv1 : sv2;
dsf_merge(sc->equiv, mj1, mj2);
mj1 = dsf_canonify(sc->equiv, mj1);
sc->slashval[mj1] = sv1;
}
}
}
if (done_something)
continue;
/*
* Failing that, we now apply the second condition, which
* is that no square may be filled in such a way as to form
* a loop. Also in this loop (since it's over squares
* rather than points), we check slashval to see if we've
* already filled in another square in the same equivalence
* class.
*
* The slashval check is disabled on DIFF_EASY, as is dead
* end avoidance. Only _immediate_ loop avoidance remains.
*/
for (y = 0; y < h; y++)
for (x = 0; x < w; x++) {
int fs, bs, v;
int c1, c2;
#ifdef SOLVER_DIAGNOSTICS
char *reason = "<internal error>";
#endif
if (soln[y*w+x])
continue; /* got this one already */
fs = FALSE;
bs = FALSE;
if (difficulty > DIFF_EASY)
v = sc->slashval[dsf_canonify(sc->equiv, y*w+x)];
else
v = 0;
/*
* Try to rule out connectivity between (x,y) and
* (x+1,y+1); if successful, we will deduce that we
* must have a forward slash.
*/
c1 = dsf_canonify(sc->connected, y*W+x);
c2 = dsf_canonify(sc->connected, (y+1)*W+(x+1));
if (c1 == c2) {
fs = TRUE;
#ifdef SOLVER_DIAGNOSTICS
reason = "simple loop avoidance";
#endif
}
if (difficulty > DIFF_EASY &&
!sc->border[c1] && !sc->border[c2] &&
sc->exits[c1] <= 1 && sc->exits[c2] <= 1) {
fs = TRUE;
#ifdef SOLVER_DIAGNOSTICS
reason = "dead end avoidance";
#endif
}
if (v == +1) {
fs = TRUE;
#ifdef SOLVER_DIAGNOSTICS
reason = "equivalence to an already filled square";
#endif
}
/*
* Now do the same between (x+1,y) and (x,y+1), to
* see if we are required to have a backslash.
*/
c1 = dsf_canonify(sc->connected, y*W+(x+1));
c2 = dsf_canonify(sc->connected, (y+1)*W+x);
if (c1 == c2) {
bs = TRUE;
#ifdef SOLVER_DIAGNOSTICS
reason = "simple loop avoidance";
#endif
}
if (difficulty > DIFF_EASY &&
!sc->border[c1] && !sc->border[c2] &&
sc->exits[c1] <= 1 && sc->exits[c2] <= 1) {
bs = TRUE;
#ifdef SOLVER_DIAGNOSTICS
reason = "dead end avoidance";
#endif
}
if (v == -1) {
bs = TRUE;
#ifdef SOLVER_DIAGNOSTICS
reason = "equivalence to an already filled square";
#endif
}
if (fs && bs) {
/*
* No consistent value for this at all!
*/
#ifdef SOLVER_DIAGNOSTICS
if (verbose)
printf("%d,%d has no consistent slash!\n", x, y);
#endif
return 0; /* impossible */
}
if (fs) {
#ifdef SOLVER_DIAGNOSTICS
if (verbose)
printf("employing %s\n", reason);
#endif
fill_square(w, h, x, y, +1, soln, sc->connected, sc);
done_something = TRUE;
} else if (bs) {
#ifdef SOLVER_DIAGNOSTICS
if (verbose)
printf("employing %s\n", reason);
#endif
fill_square(w, h, x, y, -1, soln, sc->connected, sc);
done_something = TRUE;
}
}
if (done_something)
continue;
/*
* Now see what we can do with the vbitmap array. All
* vbitmap deductions are disabled at Easy level.
*/
if (difficulty <= DIFF_EASY)
continue;
for (y = 0; y < h; y++)
for (x = 0; x < w; x++) {
int s, c;
/*
* Any line already placed in a square must rule
* out any type of v which contradicts it.
*/
if ((s = soln[y*w+x]) != 0) {
if (x > 0)
done_something |=
vbitmap_clear(w, h, sc, x-1, y, (s < 0 ? 0x1 : 0x2),
"contradicts known edge at (%d,%d)",x,y);
if (x+1 < w)
done_something |=
vbitmap_clear(w, h, sc, x, y, (s < 0 ? 0x2 : 0x1),
"contradicts known edge at (%d,%d)",x,y);
if (y > 0)
done_something |=
vbitmap_clear(w, h, sc, x, y-1, (s < 0 ? 0x4 : 0x8),
"contradicts known edge at (%d,%d)",x,y);
if (y+1 < h)
done_something |=
vbitmap_clear(w, h, sc, x, y, (s < 0 ? 0x8 : 0x4),
"contradicts known edge at (%d,%d)",x,y);
}
/*
* If both types of v are ruled out for a pair of
* adjacent squares, mark them as equivalent.
*/
if (x+1 < w && !(sc->vbitmap[y*w+x] & 0x3)) {
int n1 = y*w+x, n2 = y*w+(x+1);
if (dsf_canonify(sc->equiv, n1) !=
dsf_canonify(sc->equiv, n2)) {
dsf_merge(sc->equiv, n1, n2);
done_something = TRUE;
#ifdef SOLVER_DIAGNOSTICS
if (verbose)
printf("(%d,%d) and (%d,%d) must be equivalent"
" because both v-shapes are ruled out\n",
x, y, x+1, y);
#endif
}
}
if (y+1 < h && !(sc->vbitmap[y*w+x] & 0xC)) {
int n1 = y*w+x, n2 = (y+1)*w+x;
if (dsf_canonify(sc->equiv, n1) !=
dsf_canonify(sc->equiv, n2)) {
dsf_merge(sc->equiv, n1, n2);
done_something = TRUE;
#ifdef SOLVER_DIAGNOSTICS
if (verbose)
printf("(%d,%d) and (%d,%d) must be equivalent"
" because both v-shapes are ruled out\n",
x, y, x, y+1);
#endif
}
}
/*
* The remaining work in this loop only works
* around non-edge clue points.
*/
if (y == 0 || x == 0)
continue;
if ((c = clues[y*W+x]) < 0)
continue;
/*
* x,y marks a clue point not on the grid edge. See
* if this clue point allows us to rule out any v
* shapes.
*/
if (c == 1) {
/*
* A 1 clue can never have any v shape pointing
* at it.
*/
done_something |=
vbitmap_clear(w, h, sc, x-1, y-1, 0x5,
"points at 1 clue at (%d,%d)", x, y);
done_something |=
vbitmap_clear(w, h, sc, x-1, y, 0x2,
"points at 1 clue at (%d,%d)", x, y);
done_something |=
vbitmap_clear(w, h, sc, x, y-1, 0x8,
"points at 1 clue at (%d,%d)", x, y);
} else if (c == 3) {
/*
* A 3 clue can never have any v shape pointing
* away from it.
*/
done_something |=
vbitmap_clear(w, h, sc, x-1, y-1, 0xA,
"points away from 3 clue at (%d,%d)", x, y);
done_something |=
vbitmap_clear(w, h, sc, x-1, y, 0x1,
"points away from 3 clue at (%d,%d)", x, y);
done_something |=
vbitmap_clear(w, h, sc, x, y-1, 0x4,
"points away from 3 clue at (%d,%d)", x, y);
} else if (c == 2) {
/*
* If a 2 clue has any kind of v ruled out on
* one side of it, the same v is ruled out on
* the other side.
*/
done_something |=
vbitmap_clear(w, h, sc, x-1, y-1,
(sc->vbitmap[(y )*w+(x-1)] & 0x3) ^ 0x3,
"propagated by 2 clue at (%d,%d)", x, y);
done_something |=
vbitmap_clear(w, h, sc, x-1, y-1,
(sc->vbitmap[(y-1)*w+(x )] & 0xC) ^ 0xC,
"propagated by 2 clue at (%d,%d)", x, y);
done_something |=
vbitmap_clear(w, h, sc, x-1, y,
(sc->vbitmap[(y-1)*w+(x-1)] & 0x3) ^ 0x3,
"propagated by 2 clue at (%d,%d)", x, y);
done_something |=
vbitmap_clear(w, h, sc, x, y-1,
(sc->vbitmap[(y-1)*w+(x-1)] & 0xC) ^ 0xC,
"propagated by 2 clue at (%d,%d)", x, y);
}
#undef CLEARBITS
}
} while (done_something);
/*
* Solver can make no more progress. See if the grid is full.
*/
for (i = 0; i < w*h; i++)
if (!soln[i])
return 2; /* failed to converge */
return 1; /* success */
}
/*
* Filled-grid generator.
*/
static void slant_generate(int w, int h, signed char *soln, random_state *rs)
{
int W = w+1, H = h+1;
int x, y, i;
int *connected, *indices;
/*
* Clear the output.
*/
memset(soln, 0, w*h);
/*
* Establish a disjoint set forest for tracking connectedness
* between grid points.
*/
connected = snew_dsf(W*H);
/*
* Prepare a list of the squares in the grid, and fill them in
* in a random order.
*/
indices = snewn(w*h, int);
for (i = 0; i < w*h; i++)
indices[i] = i;
shuffle(indices, w*h, sizeof(*indices), rs);
/*
* Fill in each one in turn.
*/
for (i = 0; i < w*h; i++) {
int fs, bs, v;
y = indices[i] / w;
x = indices[i] % w;
fs = (dsf_canonify(connected, y*W+x) ==
dsf_canonify(connected, (y+1)*W+(x+1)));
bs = (dsf_canonify(connected, (y+1)*W+x) ==
dsf_canonify(connected, y*W+(x+1)));
/*
* It isn't possible to get into a situation where we
* aren't allowed to place _either_ type of slash in a
* square. Thus, filled-grid generation never has to
* backtrack.
*
* Proof (thanks to Gareth Taylor):
*
* If it were possible, it would have to be because there
* was an existing path (not using this square) between the
* top-left and bottom-right corners of this square, and
* another between the other two. These two paths would
* have to cross at some point.
*
* Obviously they can't cross in the middle of a square, so
* they must cross by sharing a point in common. But this
* isn't possible either: if you chessboard-colour all the
* points on the grid, you find that any continuous
* diagonal path is entirely composed of points of the same
* colour. And one of our two hypothetical paths is between
* two black points, and the other is between two white
* points - therefore they can have no point in common. []
*/
assert(!(fs && bs));
v = fs ? +1 : bs ? -1 : 2 * random_upto(rs, 2) - 1;
fill_square(w, h, x, y, v, soln, connected, NULL);
}
sfree(indices);
sfree(connected);
}
static char *new_game_desc(game_params *params, random_state *rs,
char **aux, int interactive)
{
int w = params->w, h = params->h, W = w+1, H = h+1;
signed char *soln, *tmpsoln, *clues;
int *clueindices;
struct solver_scratch *sc;
int x, y, v, i, j;
char *desc;
soln = snewn(w*h, signed char);
tmpsoln = snewn(w*h, signed char);
clues = snewn(W*H, signed char);
clueindices = snewn(W*H, int);
sc = new_scratch(w, h);
do {
/*
* Create the filled grid.
*/
slant_generate(w, h, soln, rs);
/*
* Fill in the complete set of clues.
*/
for (y = 0; y < H; y++)
for (x = 0; x < W; x++) {
v = 0;
if (x > 0 && y > 0 && soln[(y-1)*w+(x-1)] == -1) v++;
if (x > 0 && y < h && soln[y*w+(x-1)] == +1) v++;
if (x < w && y > 0 && soln[(y-1)*w+x] == +1) v++;
if (x < w && y < h && soln[y*w+x] == -1) v++;
clues[y*W+x] = v;
}
/*
* With all clue points filled in, all puzzles are easy: we can
* simply process the clue points in lexicographic order, and
* at each clue point we will always have at most one square
* undecided, which we can then fill in uniquely.
*/
assert(slant_solve(w, h, clues, tmpsoln, sc, DIFF_EASY) == 1);
/*
* Remove as many clues as possible while retaining solubility.
*
* In DIFF_HARD mode, we prioritise the removal of obvious
* starting points (4s, 0s, border 2s and corner 1s), on
* the grounds that having as few of these as possible
* seems like a good thing. In particular, we can often get
* away without _any_ completely obvious starting points,
* which is even better.
*/
for (i = 0; i < W*H; i++)
clueindices[i] = i;
shuffle(clueindices, W*H, sizeof(*clueindices), rs);
for (j = 0; j < 2; j++) {
for (i = 0; i < W*H; i++) {
int pass, yb, xb;
y = clueindices[i] / W;
x = clueindices[i] % W;
v = clues[y*W+x];
/*
* Identify which pass we should process this point
* in. If it's an obvious start point, _or_ we're
* in DIFF_EASY, then it goes in pass 0; otherwise
* pass 1.
*/
xb = (x == 0 || x == W-1);
yb = (y == 0 || y == H-1);
if (params->diff == DIFF_EASY || v == 4 || v == 0 ||
(v == 2 && (xb||yb)) || (v == 1 && xb && yb))
pass = 0;
else
pass = 1;
if (pass == j) {
clues[y*W+x] = -1;
if (slant_solve(w, h, clues, tmpsoln, sc,
params->diff) != 1)
clues[y*W+x] = v; /* put it back */
}
}
}
/*
* And finally, verify that the grid is of _at least_ the
* requested difficulty, by running the solver one level
* down and verifying that it can't manage it.
*/
} while (params->diff > 0 &&
slant_solve(w, h, clues, tmpsoln, sc, params->diff - 1) <= 1);
/*
* Now we have the clue set as it will be presented to the
* user. Encode it in a game desc.
*/
{
char *p;
int run, i;
desc = snewn(W*H+1, char);
p = desc;
run = 0;
for (i = 0; i <= W*H; i++) {
int n = (i < W*H ? clues[i] : -2);
if (n == -1)
run++;
else {
if (run) {
while (run > 0) {
int c = 'a' - 1 + run;
if (run > 26)
c = 'z';
*p++ = c;
run -= c - ('a' - 1);
}
}
if (n >= 0)
*p++ = '0' + n;
run = 0;
}
}
assert(p - desc <= W*H);
*p++ = '\0';
desc = sresize(desc, p - desc, char);
}
/*
* Encode the solution as an aux_info.
*/
{
char *auxbuf;
*aux = auxbuf = snewn(w*h+1, char);
for (i = 0; i < w*h; i++)
auxbuf[i] = soln[i] < 0 ? '\\' : '/';
auxbuf[w*h] = '\0';
}
free_scratch(sc);
sfree(clueindices);
sfree(clues);
sfree(tmpsoln);
sfree(soln);
return desc;
}
static char *validate_desc(game_params *params, char *desc)
{
int w = params->w, h = params->h, W = w+1, H = h+1;
int area = W*H;
int squares = 0;
while (*desc) {
int n = *desc++;
if (n >= 'a' && n <= 'z') {
squares += n - 'a' + 1;
} else if (n >= '0' && n <= '4') {
squares++;
} else
return "Invalid character in game description";
}
if (squares < area)
return "Not enough data to fill grid";
if (squares > area)
return "Too much data to fit in grid";
return NULL;
}
static game_state *new_game(midend *me, game_params *params, char *desc)
{
int w = params->w, h = params->h, W = w+1, H = h+1;
game_state *state = snew(game_state);
int area = W*H;
int squares = 0;
state->p = *params;
state->soln = snewn(w*h, signed char);
memset(state->soln, 0, w*h);
state->completed = state->used_solve = FALSE;
state->errors = snewn(W*H, unsigned char);
memset(state->errors, 0, W*H);
state->clues = snew(game_clues);
state->clues->w = w;
state->clues->h = h;
state->clues->clues = snewn(W*H, signed char);
state->clues->refcount = 1;
state->clues->tmpdsf = snewn(W*H, int);
memset(state->clues->clues, -1, W*H);
while (*desc) {
int n = *desc++;
if (n >= 'a' && n <= 'z') {
squares += n - 'a' + 1;
} else if (n >= '0' && n <= '4') {
state->clues->clues[squares++] = n - '0';
} else
assert(!"can't get here");
}
assert(squares == area);
return state;
}
static game_state *dup_game(game_state *state)
{
int w = state->p.w, h = state->p.h, W = w+1, H = h+1;
game_state *ret = snew(game_state);
ret->p = state->p;
ret->clues = state->clues;
ret->clues->refcount++;
ret->completed = state->completed;
ret->used_solve = state->used_solve;
ret->soln = snewn(w*h, signed char);
memcpy(ret->soln, state->soln, w*h);
ret->errors = snewn(W*H, unsigned char);
memcpy(ret->errors, state->errors, W*H);
return ret;
}
static void free_game(game_state *state)
{
sfree(state->errors);
sfree(state->soln);
assert(state->clues);
if (--state->clues->refcount <= 0) {
sfree(state->clues->clues);
sfree(state->clues->tmpdsf);
sfree(state->clues);
}
sfree(state);
}
/*
* Utility function to return the current degree of a vertex. If
* `anti' is set, it returns the number of filled-in edges
* surrounding the point which _don't_ connect to it; thus 4 minus
* its anti-degree is the maximum degree it could have if all the
* empty spaces around it were filled in.
*
* (Yes, _4_ minus its anti-degree even if it's a border vertex.)
*
* If ret > 0, *sx and *sy are set to the coordinates of one of the
* squares that contributed to it.
*/
static int vertex_degree(int w, int h, signed char *soln, int x, int y,
int anti, int *sx, int *sy)
{
int ret = 0;
assert(x >= 0 && x <= w && y >= 0 && y <= h);
if (x > 0 && y > 0 && soln[(y-1)*w+(x-1)] - anti < 0) {
if (sx) *sx = x-1;
if (sy) *sy = y-1;
ret++;
}
if (x > 0 && y < h && soln[y*w+(x-1)] + anti > 0) {
if (sx) *sx = x-1;
if (sy) *sy = y;
ret++;
}
if (x < w && y > 0 && soln[(y-1)*w+x] + anti > 0) {
if (sx) *sx = x;
if (sy) *sy = y-1;
ret++;
}
if (x < w && y < h && soln[y*w+x] - anti < 0) {
if (sx) *sx = x;
if (sy) *sy = y;
ret++;
}
return anti ? 4 - ret : ret;
}
static int check_completion(game_state *state)
{
int w = state->p.w, h = state->p.h, W = w+1, H = h+1;
int i, x, y, err = FALSE;
int *dsf;
memset(state->errors, 0, W*H);
/*
* To detect loops in the grid, we iterate through each edge
* building up a dsf of connected components, and raise the
* alarm whenever we find an edge that connects two
* already-connected vertices.
*
* We use the `tmpdsf' scratch space in the shared clues
* structure, to avoid mallocing too often.
*
* When we find such an edge, we then search around the grid to
* find the loop it is a part of, so that we can highlight it
* as an error for the user. We do this by the hand-on-one-wall
* technique: the search will follow branches off the inside of
* the loop, discover they're dead ends, and unhighlight them
* again when returning to the actual loop.
*
* This technique guarantees that every loop it tracks will
* surround a disjoint area of the grid (since if an existing
* loop appears on the boundary of a new one, so that there are
* multiple possible paths that would come back to the starting
* point, it will pick the one that allows it to turn right
* most sharply and hence the one that does not re-surround the
* area of the previous one). Thus, the total time taken in
* searching round loops is linear in the grid area since every
* edge is visited at most twice.
*/
dsf = state->clues->tmpdsf;
dsf_init(dsf, W*H);
for (y = 0; y < h; y++)
for (x = 0; x < w; x++) {
int i1, i2;
if (state->soln[y*w+x] == 0)
continue;
if (state->soln[y*w+x] < 0) {
i1 = y*W+x;
i2 = (y+1)*W+(x+1);
} else {
i1 = y*W+(x+1);
i2 = (y+1)*W+x;
}
/*
* Our edge connects i1 with i2. If they're already
* connected, flag an error. Otherwise, link them.
*/
if (dsf_canonify(dsf, i1) == dsf_canonify(dsf, i2)) {
int x1, y1, x2, y2, dx, dy, dt, pass;
err = TRUE;
/*
* Now search around the boundary of the loop to
* highlight it.
*
* We have to do this in two passes. The first
* time, we toggle ERR_SQUARE_TMP on each edge;
* this pass terminates with ERR_SQUARE_TMP set on
* exactly the loop edges. In the second pass, we
* trace round that loop again and turn
* ERR_SQUARE_TMP into ERR_SQUARE. We have to do
* this because otherwise we might cancel part of a
* loop highlighted in a previous iteration of the
* outer loop.
*/
for (pass = 0; pass < 2; pass++) {
x1 = i1 % W;
y1 = i1 / W;
x2 = i2 % W;
y2 = i2 / W;
do {
/* Mark this edge. */
if (pass == 0) {
state->errors[min(y1,y2)*W+min(x1,x2)] ^=
ERR_SQUARE_TMP;
} else {
state->errors[min(y1,y2)*W+min(x1,x2)] |=
ERR_SQUARE;
state->errors[min(y1,y2)*W+min(x1,x2)] &=
~ERR_SQUARE_TMP;
}
/*
* Progress to the next edge by turning as
* sharply right as possible. In fact we do
* this by facing back along the edge and
* turning _left_ until we see an edge we
* can follow.
*/
dx = x1 - x2;
dy = y1 - y2;
for (i = 0; i < 4; i++) {
/*
* Rotate (dx,dy) to the left.
*/
dt = dx; dx = dy; dy = -dt;
/*
* See if (x2,y2) has an edge in direction
* (dx,dy).
*/
if (x2+dx < 0 || x2+dx >= W ||
y2+dy < 0 || y2+dy >= H)
continue; /* off the side of the grid */
/* In the second pass, ignore unmarked edges. */
if (pass == 1 &&
!(state->errors[(y2-(dy<0))*W+x2-(dx<0)] &
ERR_SQUARE_TMP))
continue;
if (state->soln[(y2-(dy<0))*w+x2-(dx<0)] ==
(dx==dy ? -1 : +1))
break;
}
/*
* In pass 0, we expect to have found
* _some_ edge we can follow, even if it
* was found by rotating all the way round
* and going back the way we came.
*
* In pass 1, because we're removing the
* mark on each edge that allows us to
* follow it, we expect to find _no_ edge
* we can follow when we've come all the
* way round the loop.
*/
if (pass == 1 && i == 4)
break;
assert(i < 4);
/*
* Set x1,y1 to x2,y2, and x2,y2 to be the
* other end of the new edge.
*/
x1 = x2;
y1 = y2;
x2 += dx;
y2 += dy;
} while (y2*W+x2 != i2);
}
} else
dsf_merge(dsf, i1, i2);
}
/*
* Now go through and check the degree of each clue vertex, and
* mark it with ERR_VERTEX if it cannot be fulfilled.
*/
for (y = 0; y < H; y++)
for (x = 0; x < W; x++) {
int c;
if ((c = state->clues->clues[y*W+x]) < 0)
continue;
/*
* Check to see if there are too many connections to
* this vertex _or_ too many non-connections. Either is
* grounds for marking the vertex as erroneous.
*/
if (vertex_degree(w, h, state->soln, x, y,
FALSE, NULL, NULL) > c ||
vertex_degree(w, h, state->soln, x, y,
TRUE, NULL, NULL) > 4-c) {
state->errors[y*W+x] |= ERR_VERTEX;
err = TRUE;
}
}
/*
* Now our actual victory condition is that (a) none of the
* above code marked anything as erroneous, and (b) every
* square has an edge in it.
*/
if (err)
return FALSE;
for (y = 0; y < h; y++)
for (x = 0; x < w; x++)
if (state->soln[y*w+x] == 0)
return FALSE;
return TRUE;
}
static char *solve_game(game_state *state, game_state *currstate,
char *aux, char **error)
{
int w = state->p.w, h = state->p.h;
signed char *soln;
int bs, ret;
int free_soln = FALSE;
char *move, buf[80];
int movelen, movesize;
int x, y;
if (aux) {
/*
* If we already have the solution, save ourselves some
* time.
*/
soln = (signed char *)aux;
bs = (signed char)'\\';
free_soln = FALSE;
} else {
struct solver_scratch *sc = new_scratch(w, h);
soln = snewn(w*h, signed char);
bs = -1;
ret = slant_solve(w, h, state->clues->clues, soln, sc, DIFF_HARD);
free_scratch(sc);
if (ret != 1) {
sfree(soln);
if (ret == 0)
*error = "This puzzle is not self-consistent";
else
*error = "Unable to find a unique solution for this puzzle";
return NULL;
}
free_soln = TRUE;
}
/*
* Construct a move string which turns the current state into
* the solved state.
*/
movesize = 256;
move = snewn(movesize, char);
movelen = 0;
move[movelen++] = 'S';
move[movelen] = '\0';
for (y = 0; y < h; y++)
for (x = 0; x < w; x++) {
int v = (soln[y*w+x] == bs ? -1 : +1);
if (state->soln[y*w+x] != v) {
int len = sprintf(buf, ";%c%d,%d", (int)(v < 0 ? '\\' : '/'), x, y);
if (movelen + len >= movesize) {
movesize = movelen + len + 256;
move = sresize(move, movesize, char);
}
strcpy(move + movelen, buf);
movelen += len;
}
}
if (free_soln)
sfree(soln);
return move;
}
static char *game_text_format(game_state *state)
{
int w = state->p.w, h = state->p.h, W = w+1, H = h+1;
int x, y, len;
char *ret, *p;
/*
* There are h+H rows of w+W columns.
*/
len = (h+H) * (w+W+1) + 1;
ret = snewn(len, char);
p = ret;
for (y = 0; y < H; y++) {
for (x = 0; x < W; x++) {
if (state->clues->clues[y*W+x] >= 0)
*p++ = state->clues->clues[y*W+x] + '0';
else
*p++ = '+';
if (x < w)
*p++ = '-';
}
*p++ = '\n';
if (y < h) {
for (x = 0; x < W; x++) {
*p++ = '|';
if (x < w) {
if (state->soln[y*w+x] != 0)
*p++ = (state->soln[y*w+x] < 0 ? '\\' : '/');
else
*p++ = ' ';
}
}
*p++ = '\n';
}
}
*p++ = '\0';
assert(p - ret == len);
return ret;
}
static game_ui *new_ui(game_state *state)
{
return NULL;
}
static void free_ui(game_ui *ui)
{
}
static char *encode_ui(game_ui *ui)
{
return NULL;
}
static void decode_ui(game_ui *ui, char *encoding)
{
}
static void game_changed_state(game_ui *ui, game_state *oldstate,
game_state *newstate)
{
}
#define PREFERRED_TILESIZE 32
#define TILESIZE (ds->tilesize)
#define BORDER TILESIZE
#define CLUE_RADIUS (TILESIZE / 3)
#define CLUE_TEXTSIZE (TILESIZE / 2)
#define COORD(x) ( (x) * TILESIZE + BORDER )
#define FROMCOORD(x) ( ((x) - BORDER + TILESIZE) / TILESIZE - 1 )
#define FLASH_TIME 0.30F
/*
* Bit fields in the `grid' and `todraw' elements of the drawstate.
*/
#define BACKSLASH 0x00000001L
#define FORWSLASH 0x00000002L
#define L_T 0x00000004L
#define ERR_L_T 0x00000008L
#define L_B 0x00000010L
#define ERR_L_B 0x00000020L
#define T_L 0x00000040L
#define ERR_T_L 0x00000080L
#define T_R 0x00000100L
#define ERR_T_R 0x00000200L
#define C_TL 0x00000400L
#define ERR_C_TL 0x00000800L
#define FLASH 0x00001000L
#define ERRSLASH 0x00002000L
#define ERR_TL 0x00004000L
#define ERR_TR 0x00008000L
#define ERR_BL 0x00010000L
#define ERR_BR 0x00020000L
struct game_drawstate {
int tilesize;
int started;
long *grid;
long *todraw;
};
static char *interpret_move(game_state *state, game_ui *ui, game_drawstate *ds,
int x, int y, int button)
{
int w = state->p.w, h = state->p.h;
if (button == LEFT_BUTTON || button == RIGHT_BUTTON) {
int v;
char buf[80];
/*
* This is an utterly awful hack which I should really sort out
* by means of a proper configuration mechanism. One Slant
* player has observed that they prefer the mouse buttons to
* function exactly the opposite way round, so here's a
* mechanism for environment-based configuration. I cache the
* result in a global variable - yuck! - to avoid repeated
* lookups.
*/
{
static int swap_buttons = -1;
if (swap_buttons < 0) {
char *env = getenv("SLANT_SWAP_BUTTONS");
swap_buttons = (env && (env[0] == 'y' || env[0] == 'Y'));
}
if (swap_buttons) {
if (button == LEFT_BUTTON)
button = RIGHT_BUTTON;
else
button = LEFT_BUTTON;
}
}
x = FROMCOORD(x);
y = FROMCOORD(y);
if (x < 0 || y < 0 || x >= w || y >= h)
return NULL;
if (button == LEFT_BUTTON) {
/*
* Left-clicking cycles blank -> \ -> / -> blank.
*/
v = state->soln[y*w+x] - 1;
if (v == -2)
v = +1;
} else {
/*
* Right-clicking cycles blank -> / -> \ -> blank.
*/
v = state->soln[y*w+x] + 1;
if (v == +2)
v = -1;
}
sprintf(buf, "%c%d,%d", (int)(v==-1 ? '\\' : v==+1 ? '/' : 'C'), x, y);
return dupstr(buf);
}
return NULL;
}
static game_state *execute_move(game_state *state, char *move)
{
int w = state->p.w, h = state->p.h;
char c;
int x, y, n;
game_state *ret = dup_game(state);
while (*move) {
c = *move;
if (c == 'S') {
ret->used_solve = TRUE;
move++;
} else if (c == '\\' || c == '/' || c == 'C') {
move++;
if (sscanf(move, "%d,%d%n", &x, &y, &n) != 2 ||
x < 0 || y < 0 || x >= w || y >= h) {
free_game(ret);
return NULL;
}
ret->soln[y*w+x] = (c == '\\' ? -1 : c == '/' ? +1 : 0);
move += n;
} else {
free_game(ret);
return NULL;
}
if (*move == ';')
move++;
else if (*move) {
free_game(ret);
return NULL;
}
}
/*
* We never clear the `completed' flag, but we must always
* re-run the completion check because it also highlights
* errors in the grid.
*/
ret->completed = check_completion(ret) || ret->completed;
return ret;
}
/* ----------------------------------------------------------------------
* Drawing routines.
*/
static void game_compute_size(game_params *params, int tilesize,
int *x, int *y)
{
/* fool the macros */
struct dummy { int tilesize; } dummy = { tilesize }, *ds = &dummy;
*x = 2 * BORDER + params->w * TILESIZE + 1;
*y = 2 * BORDER + params->h * TILESIZE + 1;
}
static void game_set_size(drawing *dr, game_drawstate *ds,
game_params *params, int tilesize)
{
ds->tilesize = tilesize;
}
static float *game_colours(frontend *fe, int *ncolours)
{
float *ret = snewn(3 * NCOLOURS, float);
frontend_default_colour(fe, &ret[COL_BACKGROUND * 3]);
ret[COL_GRID * 3 + 0] = ret[COL_BACKGROUND * 3 + 0] * 0.7F;
ret[COL_GRID * 3 + 1] = ret[COL_BACKGROUND * 3 + 1] * 0.7F;
ret[COL_GRID * 3 + 2] = ret[COL_BACKGROUND * 3 + 2] * 0.7F;
ret[COL_INK * 3 + 0] = 0.0F;
ret[COL_INK * 3 + 1] = 0.0F;
ret[COL_INK * 3 + 2] = 0.0F;
ret[COL_SLANT1 * 3 + 0] = 0.0F;
ret[COL_SLANT1 * 3 + 1] = 0.0F;
ret[COL_SLANT1 * 3 + 2] = 0.0F;
ret[COL_SLANT2 * 3 + 0] = 0.0F;
ret[COL_SLANT2 * 3 + 1] = 0.0F;
ret[COL_SLANT2 * 3 + 2] = 0.0F;
ret[COL_ERROR * 3 + 0] = 1.0F;
ret[COL_ERROR * 3 + 1] = 0.0F;
ret[COL_ERROR * 3 + 2] = 0.0F;
*ncolours = NCOLOURS;
return ret;
}
static game_drawstate *game_new_drawstate(drawing *dr, game_state *state)
{
int w = state->p.w, h = state->p.h;
int i;
struct game_drawstate *ds = snew(struct game_drawstate);
ds->tilesize = 0;
ds->started = FALSE;
ds->grid = snewn((w+2)*(h+2), long);
ds->todraw = snewn((w+2)*(h+2), long);
for (i = 0; i < (w+2)*(h+2); i++)
ds->grid[i] = ds->todraw[i] = -1;
return ds;
}
static void game_free_drawstate(drawing *dr, game_drawstate *ds)
{
sfree(ds->todraw);
sfree(ds->grid);
sfree(ds);
}
static void draw_clue(drawing *dr, game_drawstate *ds,
int x, int y, long v, long err, int bg, int colour)
{
char p[2];
int ccol = colour >= 0 ? colour : ((x ^ y) & 1) ? COL_SLANT1 : COL_SLANT2;
int tcol = colour >= 0 ? colour : err ? COL_ERROR : COL_INK;
if (v < 0)
return;
p[0] = v + '0';
p[1] = '\0';
draw_circle(dr, COORD(x), COORD(y), CLUE_RADIUS,
bg >= 0 ? bg : COL_BACKGROUND, ccol);
draw_text(dr, COORD(x), COORD(y), FONT_VARIABLE,
CLUE_TEXTSIZE, ALIGN_VCENTRE|ALIGN_HCENTRE, tcol, p);
}
static void draw_tile(drawing *dr, game_drawstate *ds, game_clues *clues,
int x, int y, long v)
{
int w = clues->w, h = clues->h, W = w+1 /*, H = h+1 */;
int chesscolour = (x ^ y) & 1;
int fscol = chesscolour ? COL_SLANT2 : COL_SLANT1;
int bscol = chesscolour ? COL_SLANT1 : COL_SLANT2;
clip(dr, COORD(x), COORD(y), TILESIZE, TILESIZE);
draw_rect(dr, COORD(x), COORD(y), TILESIZE, TILESIZE,
(v & FLASH) ? COL_GRID : COL_BACKGROUND);
/*
* Draw the grid lines.
*/
if (x >= 0 && x < w && y >= 0)
draw_rect(dr, COORD(x), COORD(y), TILESIZE+1, 1, COL_GRID);
if (x >= 0 && x < w && y < h)
draw_rect(dr, COORD(x), COORD(y+1), TILESIZE+1, 1, COL_GRID);
if (y >= 0 && y < h && x >= 0)
draw_rect(dr, COORD(x), COORD(y), 1, TILESIZE+1, COL_GRID);
if (y >= 0 && y < h && x < w)
draw_rect(dr, COORD(x+1), COORD(y), 1, TILESIZE+1, COL_GRID);
if (x == -1 && y == -1)
draw_rect(dr, COORD(x+1), COORD(y+1), 1, 1, COL_GRID);
if (x == -1 && y == h)
draw_rect(dr, COORD(x+1), COORD(y), 1, 1, COL_GRID);
if (x == w && y == -1)
draw_rect(dr, COORD(x), COORD(y+1), 1, 1, COL_GRID);
if (x == w && y == h)
draw_rect(dr, COORD(x), COORD(y), 1, 1, COL_GRID);
/*
* Draw the slash.
*/
if (v & BACKSLASH) {
int scol = (v & ERRSLASH) ? COL_ERROR : bscol;
draw_line(dr, COORD(x), COORD(y), COORD(x+1), COORD(y+1), scol);
draw_line(dr, COORD(x)+1, COORD(y), COORD(x+1), COORD(y+1)-1,
scol);
draw_line(dr, COORD(x), COORD(y)+1, COORD(x+1)-1, COORD(y+1),
scol);
} else if (v & FORWSLASH) {
int scol = (v & ERRSLASH) ? COL_ERROR : fscol;
draw_line(dr, COORD(x+1), COORD(y), COORD(x), COORD(y+1), scol);
draw_line(dr, COORD(x+1)-1, COORD(y), COORD(x), COORD(y+1)-1,
scol);
draw_line(dr, COORD(x+1), COORD(y)+1, COORD(x)+1, COORD(y+1),
scol);
}
/*
* Draw dots on the grid corners that appear if a slash is in a
* neighbouring cell.
*/
if (v & (L_T | BACKSLASH))
draw_rect(dr, COORD(x), COORD(y)+1, 1, 1,
(v & ERR_L_T ? COL_ERROR : bscol));
if (v & (L_B | FORWSLASH))
draw_rect(dr, COORD(x), COORD(y+1)-1, 1, 1,
(v & ERR_L_B ? COL_ERROR : fscol));
if (v & (T_L | BACKSLASH))
draw_rect(dr, COORD(x)+1, COORD(y), 1, 1,
(v & ERR_T_L ? COL_ERROR : bscol));
if (v & (T_R | FORWSLASH))
draw_rect(dr, COORD(x+1)-1, COORD(y), 1, 1,
(v & ERR_T_R ? COL_ERROR : fscol));
if (v & (C_TL | BACKSLASH))
draw_rect(dr, COORD(x), COORD(y), 1, 1,
(v & ERR_C_TL ? COL_ERROR : bscol));
/*
* And finally the clues at the corners.
*/
if (x >= 0 && y >= 0)
draw_clue(dr, ds, x, y, clues->clues[y*W+x], v & ERR_TL, -1, -1);
if (x < w && y >= 0)
draw_clue(dr, ds, x+1, y, clues->clues[y*W+(x+1)], v & ERR_TR, -1, -1);
if (x >= 0 && y < h)
draw_clue(dr, ds, x, y+1, clues->clues[(y+1)*W+x], v & ERR_BL, -1, -1);
if (x < w && y < h)
draw_clue(dr, ds, x+1, y+1, clues->clues[(y+1)*W+(x+1)], v & ERR_BR,
-1, -1);
unclip(dr);
draw_update(dr, COORD(x), COORD(y), TILESIZE, TILESIZE);
}
static void game_redraw(drawing *dr, game_drawstate *ds, game_state *oldstate,
game_state *state, int dir, game_ui *ui,
float animtime, float flashtime)
{
int w = state->p.w, h = state->p.h, W = w+1, H = h+1;
int x, y;
int flashing;
if (flashtime > 0)
flashing = (int)(flashtime * 3 / FLASH_TIME) != 1;
else
flashing = FALSE;
if (!ds->started) {
int ww, wh;
game_compute_size(&state->p, TILESIZE, &ww, &wh);
draw_rect(dr, 0, 0, ww, wh, COL_BACKGROUND);
draw_update(dr, 0, 0, ww, wh);
ds->started = TRUE;
}
/*
* Loop over the grid and work out where all the slashes are.
* We need to do this because a slash in one square affects the
* drawing of the next one along.
*/
for (y = -1; y <= h; y++)
for (x = -1; x <= w; x++) {
if (x >= 0 && x < w && y >= 0 && y < h)
ds->todraw[(y+1)*(w+2)+(x+1)] = flashing ? FLASH : 0;
else
ds->todraw[(y+1)*(w+2)+(x+1)] = 0;
}
for (y = 0; y < h; y++) {
for (x = 0; x < w; x++) {
int err = state->errors[y*W+x] & ERR_SQUARE;
if (state->soln[y*w+x] < 0) {
ds->todraw[(y+1)*(w+2)+(x+1)] |= BACKSLASH;
ds->todraw[(y+2)*(w+2)+(x+1)] |= T_R;
ds->todraw[(y+1)*(w+2)+(x+2)] |= L_B;
ds->todraw[(y+2)*(w+2)+(x+2)] |= C_TL;
if (err) {
ds->todraw[(y+1)*(w+2)+(x+1)] |= ERRSLASH |
ERR_T_L | ERR_L_T | ERR_C_TL;
ds->todraw[(y+2)*(w+2)+(x+1)] |= ERR_T_R;
ds->todraw[(y+1)*(w+2)+(x+2)] |= ERR_L_B;
ds->todraw[(y+2)*(w+2)+(x+2)] |= ERR_C_TL;
}
} else if (state->soln[y*w+x] > 0) {
ds->todraw[(y+1)*(w+2)+(x+1)] |= FORWSLASH;
ds->todraw[(y+1)*(w+2)+(x+2)] |= L_T | C_TL;
ds->todraw[(y+2)*(w+2)+(x+1)] |= T_L | C_TL;
if (err) {
ds->todraw[(y+1)*(w+2)+(x+1)] |= ERRSLASH |
ERR_L_B | ERR_T_R;
ds->todraw[(y+1)*(w+2)+(x+2)] |= ERR_L_T | ERR_C_TL;
ds->todraw[(y+2)*(w+2)+(x+1)] |= ERR_T_L | ERR_C_TL;
}
}
}
}
for (y = 0; y < H; y++)
for (x = 0; x < W; x++)
if (state->errors[y*W+x] & ERR_VERTEX) {
ds->todraw[y*(w+2)+x] |= ERR_BR;
ds->todraw[y*(w+2)+(x+1)] |= ERR_BL;
ds->todraw[(y+1)*(w+2)+x] |= ERR_TR;
ds->todraw[(y+1)*(w+2)+(x+1)] |= ERR_TL;
}
/*
* Now go through and draw the grid squares.
*/
for (y = -1; y <= h; y++) {
for (x = -1; x <= w; x++) {
if (ds->todraw[(y+1)*(w+2)+(x+1)] != ds->grid[(y+1)*(w+2)+(x+1)]) {
draw_tile(dr, ds, state->clues, x, y,
ds->todraw[(y+1)*(w+2)+(x+1)]);
ds->grid[(y+1)*(w+2)+(x+1)] = ds->todraw[(y+1)*(w+2)+(x+1)];
}
}
}
}
static float game_anim_length(game_state *oldstate, game_state *newstate,
int dir, game_ui *ui)
{
return 0.0F;
}
static float game_flash_length(game_state *oldstate, game_state *newstate,
int dir, game_ui *ui)
{
if (!oldstate->completed && newstate->completed &&
!oldstate->used_solve && !newstate->used_solve)
return FLASH_TIME;
return 0.0F;
}
static int game_timing_state(game_state *state, game_ui *ui)
{
return TRUE;
}
static void game_print_size(game_params *params, float *x, float *y)
{
int pw, ph;
/*
* I'll use 6mm squares by default.
*/
game_compute_size(params, 600, &pw, &ph);
*x = pw / 100.0;
*y = ph / 100.0;
}
static void game_print(drawing *dr, game_state *state, int tilesize)
{
int w = state->p.w, h = state->p.h, W = w+1;
int ink = print_mono_colour(dr, 0);
int paper = print_mono_colour(dr, 1);
int x, y;
/* Ick: fake up `ds->tilesize' for macro expansion purposes */
game_drawstate ads, *ds = &ads;
game_set_size(dr, ds, NULL, tilesize);
/*
* Border.
*/
print_line_width(dr, TILESIZE / 16);
draw_rect_outline(dr, COORD(0), COORD(0), w*TILESIZE, h*TILESIZE, ink);
/*
* Grid.
*/
print_line_width(dr, TILESIZE / 24);
for (x = 1; x < w; x++)
draw_line(dr, COORD(x), COORD(0), COORD(x), COORD(h), ink);
for (y = 1; y < h; y++)
draw_line(dr, COORD(0), COORD(y), COORD(w), COORD(y), ink);
/*
* Solution.
*/
print_line_width(dr, TILESIZE / 12);
for (y = 0; y < h; y++)
for (x = 0; x < w; x++)
if (state->soln[y*w+x]) {
int ly, ry;
/*
* To prevent nasty line-ending artefacts at
* corners, I'll do something slightly cunning
* here.
*/
clip(dr, COORD(x), COORD(y), TILESIZE, TILESIZE);
if (state->soln[y*w+x] < 0)
ly = y-1, ry = y+2;
else
ry = y-1, ly = y+2;
draw_line(dr, COORD(x-1), COORD(ly), COORD(x+2), COORD(ry),
ink);
unclip(dr);
}
/*
* Clues.
*/
print_line_width(dr, TILESIZE / 24);
for (y = 0; y <= h; y++)
for (x = 0; x <= w; x++)
draw_clue(dr, ds, x, y, state->clues->clues[y*W+x],
FALSE, paper, ink);
}
#ifdef COMBINED
#define thegame slant
#endif
const struct game thegame = {
"Slant", "games.slant", "slant",
default_params,
game_fetch_preset,
decode_params,
encode_params,
free_params,
dup_params,
TRUE, game_configure, custom_params,
validate_params,
new_game_desc,
validate_desc,
new_game,
dup_game,
free_game,
TRUE, solve_game,
TRUE, game_text_format,
new_ui,
free_ui,
encode_ui,
decode_ui,
game_changed_state,
interpret_move,
execute_move,
PREFERRED_TILESIZE, game_compute_size, game_set_size,
game_colours,
game_new_drawstate,
game_free_drawstate,
game_redraw,
game_anim_length,
game_flash_length,
TRUE, FALSE, game_print_size, game_print,
FALSE, /* wants_statusbar */
FALSE, game_timing_state,
0, /* flags */
};
#ifdef STANDALONE_SOLVER
#include <stdarg.h>
int main(int argc, char **argv)
{
game_params *p;
game_state *s;
char *id = NULL, *desc, *err;
int grade = FALSE;
int ret, diff, really_verbose = FALSE;
struct solver_scratch *sc;
while (--argc > 0) {
char *p = *++argv;
if (!strcmp(p, "-v")) {
really_verbose = TRUE;
} else if (!strcmp(p, "-g")) {
grade = TRUE;
} else if (*p == '-') {
fprintf(stderr, "%s: unrecognised option `%s'\n", argv[0], p);
return 1;
} else {
id = p;
}
}
if (!id) {
fprintf(stderr, "usage: %s [-g | -v] <game_id>\n", argv[0]);
return 1;
}
desc = strchr(id, ':');
if (!desc) {
fprintf(stderr, "%s: game id expects a colon in it\n", argv[0]);
return 1;
}
*desc++ = '\0';
p = default_params();
decode_params(p, id);
err = validate_desc(p, desc);
if (err) {
fprintf(stderr, "%s: %s\n", argv[0], err);
return 1;
}
s = new_game(NULL, p, desc);
sc = new_scratch(p->w, p->h);
/*
* When solving an Easy puzzle, we don't want to bother the
* user with Hard-level deductions. For this reason, we grade
* the puzzle internally before doing anything else.
*/
ret = -1; /* placate optimiser */
for (diff = 0; diff < DIFFCOUNT; diff++) {
ret = slant_solve(p->w, p->h, s->clues->clues,
s->soln, sc, diff);
if (ret < 2)
break;
}
if (diff == DIFFCOUNT) {
if (grade)
printf("Difficulty rating: harder than Hard, or ambiguous\n");
else
printf("Unable to find a unique solution\n");
} else {
if (grade) {
if (ret == 0)
printf("Difficulty rating: impossible (no solution exists)\n");
else if (ret == 1)
printf("Difficulty rating: %s\n", slant_diffnames[diff]);
} else {
verbose = really_verbose;
ret = slant_solve(p->w, p->h, s->clues->clues,
s->soln, sc, diff);
if (ret == 0)
printf("Puzzle is inconsistent\n");
else
fputs(game_text_format(s), stdout);
}
}
return 0;
}
#endif
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