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puzzles/slant.c
Simon Tatham af59dcf685 Substantial infrastructure upheaval. I've separated the drawing API 
as seen by the back ends from the one implemented by the front end,
and shoved a piece of middleware (drawing.c) in between to permit
interchange of multiple kinds of the latter. I've also added a
number of functions to the drawing API to permit printing as well as
on-screen drawing, and retired print.py in favour of integrated
printing done by means of that API.

The immediate visible change is that print.py is dead, and each
puzzle now does its own printing: where you would previously have
typed `print.py solo 2x3', you now type `solo --print 2x3' and it
should work in much the same way.

Advantages of the new mechanism available right now:
 - Map is now printable, because the new print function can make use
   of the output from the existing game ID decoder rather than me
   having to replicate all those fiddly algorithms in Python.
 - the new print functions can cope with non-initial game states,
   which means each puzzle supporting --print also supports
   --with-solutions.
 - there's also a --scale option permitting users to adjust the size
   of the printed puzzles.

Advantages which will be available at some point:
 - the new API should permit me to implement native printing
   mechanisms on Windows and OS X.

[originally from svn r6190]
2005-08-18 17:50:14 +00:00

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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 <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;
signed char *tmpsoln;
int refcount;
} game_clues;
#define ERR_VERTEX 1
#define ERR_SQUARE 2
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;
/*
* 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);
return ret;
}
static void free_scratch(struct solver_scratch *sc)
{
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));
}
}
}
/*
* 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.
*/
for (i = 0; i < W*H; i++)
sc->connected[i] = i; /* initially all distinct */
/*
* Establish a disjoint set forest for tracking which squares
* are known to slant in the same direction.
*/
for (i = 0; i < w*h; i++)
sc->equiv[i] = i; /* initially all distinct */
/*
* Clear the slashval array.
*/
memset(sc->slashval, 0, w*h);
/*
* Initialise the `exits' and `border' arrays. Theses is 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];
}
/*
* Make a one-off preliminary pass over the grid looking for
* starting-point arrangements. The ones we need to spot are:
*
* - two adjacent 1s in the centre of the grid imply that each
* one's single line points towards the other. (If either 1
* were connected on the far side, the two squares shared
* between the 1s would both link to the other 1 as a
* consequence of neither linking to the first.) Thus, we
* can fill in the four squares around them.
*
* - dually, two adjacent 3s imply that each one's _non_-line
* points towards the other.
*
* - if the pair of 1s and 3s is not _adjacent_ but is
* separated by one or more 2s, the reasoning still applies.
*
* This is more advanced than just spotting obvious starting
* squares such as central 4s and edge 2s, so we disable it on
* DIFF_EASY.
*
* (I don't like this loop; it feels grubby to me. My
* mathematical intuition feels there ought to be some more
* general deductive form which contains this loop as a special
* case, but I can't bring it to mind right now.)
*/
if (difficulty > DIFF_EASY) {
for (y = 1; y+1 < H; y++)
for (x = 1; x+1 < W; x++) {
int v = clues[y*W+x], s, x2, y2, dx, dy;
if (v != 1 && v != 3)
continue;
/* Slash value of the square up and left of (x,y). */
s = (v == 1 ? +1 : -1);
/* Look in each direction once. */
for (dy = 0; dy < 2; dy++) {
dx = 1 - dy;
x2 = x+dx;
y2 = y+dy;
if (x2+1 >= W || y2+1 >= H)
continue; /* too close to the border */
while (x2+dx+1 < W && y2+dy+1 < H && clues[y2*W+x2] == 2)
x2 += dx, y2 += dy;
if (clues[y2*W+x2] == v) {
#ifdef SOLVER_DIAGNOSTICS
if (verbose)
printf("found adjacent %ds at %d,%d and %d,%d\n",
v, x, y, x2, y2);
#endif
fill_square(w, h, x-1, y-1, s, soln,
sc->connected, sc);
fill_square(w, h, x-1+dy, y-1+dx, -s, soln,
sc->connected, sc);
fill_square(w, h, x2, y2, s, soln,
sc->connected, sc);
fill_square(w, h, x2-dy, y2-dx, -s, soln,
sc->connected, sc);
}
}
}
}
/*
* 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;
}
}
} 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 = snewn(W*H, int);
for (i = 0; i < W*H; i++)
connected[i] = i; /* initially all distinct */
/*
* 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->tmpsoln = snewn(w*h, signed char);
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->tmpsoln);
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 x, y, err = FALSE;
signed char *ts;
memset(state->errors, 0, W*H);
/*
* An easy way to do loop checking would be by means of the
* same dsf technique we've used elsewhere (loop over all edges
* in the grid, joining vertices together into equivalence
* classes when connected by an edge, and raise the alarm when
* an edge joins two already-equivalent vertices). However, a
* better approach is to repeatedly remove the single edge
* connecting to any degree-1 vertex, and then see if there are
* any edges left over; if so, precisely those edges are part
* of loops, which means we can highlight them as errors for
* the user.
*
* We use the `tmpsoln' scratch space in the shared clues
* structure, to avoid mallocing too often.
*/
ts = state->clues->tmpsoln;
memcpy(ts, state->soln, w*h);
for (y = 0; y < H; y++)
for (x = 0; x < W; x++) {
int vx = x, vy = y;
int sx, sy;
/*
* Every time we disconnect a vertex like this, there
* is precisely one other vertex which might have
* become degree 1; so we follow the trail as far as it
* leads. This ensures that we don't have to make more
* than one loop over the grid, because whenever a
* degree-1 vertex comes into existence somewhere we've
* already looked, we immediately remove it again.
* Hence one loop over the grid is adequate; and
* moreover, this algorithm visits every vertex at most
* twice (once in the loop and possibly once more as a
* result of following a trail) so it has linear time
* in the area of the grid.
*/
while (vertex_degree(w, h, ts, vx, vy, FALSE, &sx, &sy) == 1) {
ts[sy*w+sx] = 0;
vx = vx + 1 + (sx - vx) * 2;
vy = vy + 1 + (sy - vy) * 2;
}
}
/*
* Now mark any remaining edges with ERR_SQUARE.
*/
for (y = 0; y < h; y++)
for (x = 0; x < w; x++)
if (ts[y*w+x]) {
state->errors[y*W+x] |= ERR_SQUARE;
err = TRUE;
}
/*
* 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, game_state *state, 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_wants_statusbar(void)
{
return FALSE;
}
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;
ads.tilesize = 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",
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,
game_wants_statusbar,
FALSE, game_timing_state,
0, /* mouse_priorities */
};
#ifdef STANDALONE_SOLVER
#include <stdarg.h>
/*
* gcc -DSTANDALONE_SOLVER -o slantsolver slant.c malloc.c
*/
void frontend_default_colour(frontend *fe, float *output) {}
void draw_text(drawing *dr, int x, int y, int fonttype, int fontsize,
int align, int colour, char *text) {}
void draw_rect(drawing *dr, int x, int y, int w, int h, int colour) {}
void draw_rect_outline(drawing *dr, int x, int y, int w, int h, int colour) {}
void draw_line(drawing *dr, int x1, int y1, int x2, int y2, int colour) {}
void draw_polygon(drawing *dr, int *coords, int npoints,
int fillcolour, int outlinecolour) {}
void draw_circle(drawing *dr, int cx, int cy, int radius,
int fillcolour, int outlinecolour) {}
void clip(drawing *dr, int x, int y, int w, int h) {}
void unclip(drawing *dr) {}
void start_draw(drawing *dr) {}
void draw_update(drawing *dr, int x, int y, int w, int h) {}
void end_draw(drawing *dr) {}
int print_mono_colour(drawing *dr, int grey) { return 0; }
void print_line_width(drawing *dr, int width) {}
unsigned long random_bits(random_state *state, int bits)
{ assert(!"Shouldn't get randomness"); return 0; }
unsigned long random_upto(random_state *state, unsigned long limit)
{ assert(!"Shouldn't get randomness"); return 0; }
void shuffle(void *array, int nelts, int eltsize, random_state *rs)
{ assert(!"Shouldn't get randomness"); }
void fatal(char *fmt, ...)
{
va_list ap;
fprintf(stderr, "fatal error: ");
va_start(ap, fmt);
vfprintf(stderr, fmt, ap);
va_end(ap);
fprintf(stderr, "\n");
exit(1);
}
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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