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netslide.c
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netslide.c
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/*
* netslide.c: cross between Net and Sixteen, courtesy of Richard
* Boulton.
*/
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <assert.h>
#include <ctype.h>
#include <limits.h>
#ifdef NO_TGMATH_H
# include <math.h>
#else
# include <tgmath.h>
#endif
#include "puzzles.h"
#include "tree234.h"
#define MATMUL(xr,yr,m,x,y) do { \
float rx, ry, xx = (x), yy = (y), *mat = (m); \
rx = mat[0] * xx + mat[2] * yy; \
ry = mat[1] * xx + mat[3] * yy; \
(xr) = rx; (yr) = ry; \
} while (0)
/* Direction and other bitfields */
#define R 0x01
#define U 0x02
#define L 0x04
#define D 0x08
#define FLASHING 0x10
#define ACTIVE 0x20
/* Corner flags go in the barriers array */
#define RU 0x10
#define UL 0x20
#define LD 0x40
#define DR 0x80
/* Get tile at given coordinate */
#define T(state, x, y) ( (y) * (state)->width + (x) )
/* Rotations: Anticlockwise, Clockwise, Flip, general rotate */
#define A(x) ( (((x) & 0x07) << 1) | (((x) & 0x08) >> 3) )
#define C(x) ( (((x) & 0x0E) >> 1) | (((x) & 0x01) << 3) )
#define F(x) ( (((x) & 0x0C) >> 2) | (((x) & 0x03) << 2) )
#define ROT(x, n) ( ((n)&3) == 0 ? (x) : \
((n)&3) == 1 ? A(x) : \
((n)&3) == 2 ? F(x) : C(x) )
/* X and Y displacements */
#define X(x) ( (x) == R ? +1 : (x) == L ? -1 : 0 )
#define Y(x) ( (x) == D ? +1 : (x) == U ? -1 : 0 )
/* Bit count */
#define COUNT(x) ( (((x) & 0x08) >> 3) + (((x) & 0x04) >> 2) + \
(((x) & 0x02) >> 1) + ((x) & 0x01) )
#define PREFERRED_TILE_SIZE 48
#define TILE_SIZE (ds->tilesize)
#define BORDER TILE_SIZE
#define TILE_BORDER 1
#define WINDOW_OFFSET 0
#define ANIM_TIME 0.13F
#define FLASH_FRAME 0.07F
enum {
COL_BACKGROUND,
COL_FLASHING,
COL_BORDER,
COL_WIRE,
COL_ENDPOINT,
COL_POWERED,
COL_BARRIER,
COL_LOWLIGHT,
COL_TEXT,
NCOLOURS
};
struct game_params {
int width;
int height;
bool wrapping;
float barrier_probability;
int movetarget;
};
struct game_state {
int width, height, cx, cy, completed;
bool wrapping, used_solve;
int move_count, movetarget;
/* position (row or col number, starting at 0) of last move. */
int last_move_row, last_move_col;
/* direction of last move: +1 or -1 */
int last_move_dir;
unsigned char *tiles;
unsigned char *barriers;
};
#define OFFSET(x2,y2,x1,y1,dir,state) \
( (x2) = ((x1) + (state)->width + X((dir))) % (state)->width, \
(y2) = ((y1) + (state)->height + Y((dir))) % (state)->height)
#define index(state, a, x, y) ( a[(y) * (state)->width + (x)] )
#define tile(state, x, y) index(state, (state)->tiles, x, y)
#define barrier(state, x, y) index(state, (state)->barriers, x, y)
struct xyd {
int x, y, direction;
};
static int xyd_cmp(void *av, void *bv) {
struct xyd *a = (struct xyd *)av;
struct xyd *b = (struct xyd *)bv;
if (a->x < b->x)
return -1;
if (a->x > b->x)
return +1;
if (a->y < b->y)
return -1;
if (a->y > b->y)
return +1;
if (a->direction < b->direction)
return -1;
if (a->direction > b->direction)
return +1;
return 0;
}
static struct xyd *new_xyd(int x, int y, int direction)
{
struct xyd *xyd = snew(struct xyd);
xyd->x = x;
xyd->y = y;
xyd->direction = direction;
return xyd;
}
static void slide_col(game_state *state, int dir, int col);
static void slide_col_int(int w, int h, unsigned char *tiles, int dir, int col);
static void slide_row(game_state *state, int dir, int row);
static void slide_row_int(int w, int h, unsigned char *tiles, int dir, int row);
/* ----------------------------------------------------------------------
* Manage game parameters.
*/
static game_params *default_params(void)
{
game_params *ret = snew(game_params);
ret->width = 3;
ret->height = 3;
ret->wrapping = false;
ret->barrier_probability = 1.0;
ret->movetarget = 0;
return ret;
}
static const struct { int x, y, wrap, bprob; const char* desc; }
netslide_presets[] = {
{3, 3, false, 1, " easy"},
{3, 3, false, 0, " medium"},
{3, 3, true, 0, " hard"},
{4, 4, false, 1, " easy"},
{4, 4, false, 0, " medium"},
{4, 4, true, 0, " hard"},
{5, 5, false, 1, " easy"},
{5, 5, false, 0, " medium"},
{5, 5, true, 0, " hard"},
};
static bool game_fetch_preset(int i, char **name, game_params **params)
{
game_params *ret;
char str[80];
if (i < 0 || i >= lenof(netslide_presets))
return false;
ret = snew(game_params);
ret->width = netslide_presets[i].x;
ret->height = netslide_presets[i].y;
ret->wrapping = netslide_presets[i].wrap;
ret->barrier_probability = (float)netslide_presets[i].bprob;
ret->movetarget = 0;
sprintf(str, "%dx%d%s", ret->width, ret->height, netslide_presets[i].desc);
*name = dupstr(str);
*params = ret;
return true;
}
static void free_params(game_params *params)
{
sfree(params);
}
static game_params *dup_params(const 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)
{
char const *p = string;
ret->wrapping = false;
ret->barrier_probability = 0.0;
ret->movetarget = 0;
ret->width = atoi(p);
while (*p && isdigit((unsigned char)*p)) p++;
if (*p == 'x') {
p++;
ret->height = atoi(p);
while (*p && isdigit((unsigned char)*p)) p++;
ret->wrapping = (*p == 'w');
if (ret->wrapping)
p++;
if (*p == 'b') {
ret->barrier_probability = (float)atof(++p);
while (*p && (isdigit((unsigned char)*p) || *p == '.')) p++;
}
if (*p == 'm') {
ret->movetarget = atoi(++p);
}
} else {
ret->height = ret->width;
}
}
static char *encode_params(const game_params *params, bool full)
{
char ret[400];
int len;
len = sprintf(ret, "%dx%d", params->width, params->height);
if (params->wrapping)
ret[len++] = 'w';
if (full && params->barrier_probability)
len += sprintf(ret+len, "b%g", params->barrier_probability);
/* Shuffle limit is part of the limited parameters, because we have to
* provide the target move count. */
if (params->movetarget)
len += sprintf(ret+len, "m%d", params->movetarget);
assert(len < lenof(ret));
ret[len] = '\0';
return dupstr(ret);
}
static config_item *game_configure(const game_params *params)
{
config_item *ret;
char buf[80];
ret = snewn(6, config_item);
ret[0].name = "Width";
ret[0].type = C_STRING;
sprintf(buf, "%d", params->width);
ret[0].u.string.sval = dupstr(buf);
ret[1].name = "Height";
ret[1].type = C_STRING;
sprintf(buf, "%d", params->height);
ret[1].u.string.sval = dupstr(buf);
ret[2].name = "Walls wrap around";
ret[2].type = C_BOOLEAN;
ret[2].u.boolean.bval = params->wrapping;
ret[3].name = "Barrier probability";
ret[3].type = C_STRING;
sprintf(buf, "%g", params->barrier_probability);
ret[3].u.string.sval = dupstr(buf);
ret[4].name = "Number of shuffling moves";
ret[4].type = C_STRING;
sprintf(buf, "%d", params->movetarget);
ret[4].u.string.sval = dupstr(buf);
ret[5].name = NULL;
ret[5].type = C_END;
return ret;
}
static game_params *custom_params(const config_item *cfg)
{
game_params *ret = snew(game_params);
ret->width = atoi(cfg[0].u.string.sval);
ret->height = atoi(cfg[1].u.string.sval);
ret->wrapping = cfg[2].u.boolean.bval;
ret->barrier_probability = (float)atof(cfg[3].u.string.sval);
ret->movetarget = atoi(cfg[4].u.string.sval);
return ret;
}
static const char *validate_params(const game_params *params, bool full)
{
if (params->width <= 1 || params->height <= 1)
return "Width and height must both be greater than one";
if (params->width > INT_MAX / params->height)
return "Width times height must not be unreasonably large";
if (params->barrier_probability < 0)
return "Barrier probability may not be negative";
if (params->barrier_probability > 1)
return "Barrier probability may not be greater than 1";
return NULL;
}
/* ----------------------------------------------------------------------
* Randomly select a new game description.
*/
static char *new_game_desc(const game_params *params, random_state *rs,
char **aux, bool interactive)
{
tree234 *possibilities, *barriertree;
int w, h, x, y, cx, cy, nbarriers;
unsigned char *tiles, *barriers;
char *desc, *p;
w = params->width;
h = params->height;
tiles = snewn(w * h, unsigned char);
memset(tiles, 0, w * h);
barriers = snewn(w * h, unsigned char);
memset(barriers, 0, w * h);
cx = w / 2;
cy = h / 2;
/*
* Construct the unshuffled grid.
*
* To do this, we simply start at the centre point, repeatedly
* choose a random possibility out of the available ways to
* extend a used square into an unused one, and do it. After
* extending the third line out of a square, we remove the
* fourth from the possibilities list to avoid any full-cross
* squares (which would make the game too easy because they
* only have one orientation).
*
* The slightly worrying thing is the avoidance of full-cross
* squares. Can this cause our unsophisticated construction
* algorithm to paint itself into a corner, by getting into a
* situation where there are some unreached squares and the
* only way to reach any of them is to extend a T-piece into a
* full cross?
*
* Answer: no it can't, and here's a proof.
*
* Any contiguous group of such unreachable squares must be
* surrounded on _all_ sides by T-pieces pointing away from the
* group. (If not, then there is a square which can be extended
* into one of the `unreachable' ones, and so it wasn't
* unreachable after all.) In particular, this implies that
* each contiguous group of unreachable squares must be
* rectangular in shape (any deviation from that yields a
* non-T-piece next to an `unreachable' square).
*
* So we have a rectangle of unreachable squares, with T-pieces
* forming a solid border around the rectangle. The corners of
* that border must be connected (since every tile connects all
* the lines arriving in it), and therefore the border must
* form a closed loop around the rectangle.
*
* But this can't have happened in the first place, since we
* _know_ we've avoided creating closed loops! Hence, no such
* situation can ever arise, and the naive grid construction
* algorithm will guaranteeably result in a complete grid
* containing no unreached squares, no full crosses _and_ no
* closed loops. []
*/
possibilities = newtree234(xyd_cmp);
if (cx+1 < w)
add234(possibilities, new_xyd(cx, cy, R));
if (cy-1 >= 0)
add234(possibilities, new_xyd(cx, cy, U));
if (cx-1 >= 0)
add234(possibilities, new_xyd(cx, cy, L));
if (cy+1 < h)
add234(possibilities, new_xyd(cx, cy, D));
while (count234(possibilities) > 0) {
int i;
struct xyd *xyd;
int x1, y1, d1, x2, y2, d2, d;
/*
* Extract a randomly chosen possibility from the list.
*/
i = random_upto(rs, count234(possibilities));
xyd = delpos234(possibilities, i);
x1 = xyd->x;
y1 = xyd->y;
d1 = xyd->direction;
sfree(xyd);
OFFSET(x2, y2, x1, y1, d1, params);
d2 = F(d1);
#ifdef GENERATION_DIAGNOSTICS
printf("picked (%d,%d,%c) <-> (%d,%d,%c)\n",
x1, y1, "0RU3L567D9abcdef"[d1], x2, y2, "0RU3L567D9abcdef"[d2]);
#endif
/*
* Make the connection. (We should be moving to an as yet
* unused tile.)
*/
index(params, tiles, x1, y1) |= d1;
assert(index(params, tiles, x2, y2) == 0);
index(params, tiles, x2, y2) |= d2;
/*
* If we have created a T-piece, remove its last
* possibility.
*/
if (COUNT(index(params, tiles, x1, y1)) == 3) {
struct xyd xyd1, *xydp;
xyd1.x = x1;
xyd1.y = y1;
xyd1.direction = 0x0F ^ index(params, tiles, x1, y1);
xydp = find234(possibilities, &xyd1, NULL);
if (xydp) {
#ifdef GENERATION_DIAGNOSTICS
printf("T-piece; removing (%d,%d,%c)\n",
xydp->x, xydp->y, "0RU3L567D9abcdef"[xydp->direction]);
#endif
del234(possibilities, xydp);
sfree(xydp);
}
}
/*
* Remove all other possibilities that were pointing at the
* tile we've just moved into.
*/
for (d = 1; d < 0x10; d <<= 1) {
int x3, y3, d3;
struct xyd xyd1, *xydp;
OFFSET(x3, y3, x2, y2, d, params);
d3 = F(d);
xyd1.x = x3;
xyd1.y = y3;
xyd1.direction = d3;
xydp = find234(possibilities, &xyd1, NULL);
if (xydp) {
#ifdef GENERATION_DIAGNOSTICS
printf("Loop avoidance; removing (%d,%d,%c)\n",
xydp->x, xydp->y, "0RU3L567D9abcdef"[xydp->direction]);
#endif
del234(possibilities, xydp);
sfree(xydp);
}
}
/*
* Add new possibilities to the list for moving _out_ of
* the tile we have just moved into.
*/
for (d = 1; d < 0x10; d <<= 1) {
int x3, y3;
if (d == d2)
continue; /* we've got this one already */
if (!params->wrapping) {
if (d == U && y2 == 0)
continue;
if (d == D && y2 == h-1)
continue;
if (d == L && x2 == 0)
continue;
if (d == R && x2 == w-1)
continue;
}
OFFSET(x3, y3, x2, y2, d, params);
if (index(params, tiles, x3, y3))
continue; /* this would create a loop */
#ifdef GENERATION_DIAGNOSTICS
printf("New frontier; adding (%d,%d,%c)\n",
x2, y2, "0RU3L567D9abcdef"[d]);
#endif
add234(possibilities, new_xyd(x2, y2, d));
}
}
/* Having done that, we should have no possibilities remaining. */
assert(count234(possibilities) == 0);
freetree234(possibilities);
/*
* Now compute a list of the possible barrier locations.
*/
barriertree = newtree234(xyd_cmp);
for (y = 0; y < h; y++) {
for (x = 0; x < w; x++) {
if (!(index(params, tiles, x, y) & R) &&
(params->wrapping || x < w-1))
add234(barriertree, new_xyd(x, y, R));
if (!(index(params, tiles, x, y) & D) &&
(params->wrapping || y < h-1))
add234(barriertree, new_xyd(x, y, D));
}
}
/*
* Save the unshuffled grid in aux.
*/
{
char *solution;
int i;
/*
* String format is exactly the same as a solve move, so we
* can just dupstr this in solve_game().
*/
solution = snewn(w * h + 2, char);
solution[0] = 'S';
for (i = 0; i < w * h; i++)
solution[i+1] = "0123456789abcdef"[tiles[i] & 0xF];
solution[w*h+1] = '\0';
*aux = solution;
}
/*
* Now shuffle the grid.
* FIXME - this simply does a set of random moves to shuffle the pieces,
* although we make a token effort to avoid boring cases by avoiding moves
* that directly undo the previous one, or that repeat so often as to
* turn into fewer moves.
*
* A better way would be to number all the pieces, generate a placement
* for all the numbers as for "sixteen", observing parity constraints if
* neccessary, and then place the pieces according to their numbering.
* BUT - I'm not sure if this will work, since we disallow movement of
* the middle row and column.
*/
{
int i;
int cols = w - 1;
int rows = h - 1;
int moves = params->movetarget;
int prevdir = -1, prevrowcol = -1, nrepeats = 0;
if (!moves) moves = cols * rows * 2;
for (i = 0; i < moves; /* incremented conditionally */) {
/* Choose a direction: 0,1,2,3 = up, right, down, left. */
int dir = random_upto(rs, 4);
int rowcol;
if (dir % 2 == 0) {
int col = random_upto(rs, cols);
if (col >= cx) col += 1; /* avoid centre */
if (col == prevrowcol) {
if (dir == 2-prevdir)
continue; /* undoes last move */
else if (dir == prevdir && (nrepeats+1)*2 > h)
continue; /* makes fewer moves */
}
slide_col_int(w, h, tiles, 1 - dir, col);
rowcol = col;
} else {
int row = random_upto(rs, rows);
if (row >= cy) row += 1; /* avoid centre */
if (row == prevrowcol) {
if (dir == 4-prevdir)
continue; /* undoes last move */
else if (dir == prevdir && (nrepeats+1)*2 > w)
continue; /* makes fewer moves */
}
slide_row_int(w, h, tiles, 2 - dir, row);
rowcol = row;
}
if (dir == prevdir && rowcol == prevrowcol)
nrepeats++;
else
nrepeats = 1;
prevdir = dir;
prevrowcol = rowcol;
i++; /* if we got here, the move was accepted */
}
}
/*
* And now choose barrier locations. (We carefully do this
* _after_ shuffling, so that changing the barrier rate in the
* params while keeping the random seed the same will give the
* same shuffled grid and _only_ change the barrier locations.
* Also the way we choose barrier locations, by repeatedly
* choosing one possibility from the list until we have enough,
* is designed to ensure that raising the barrier rate while
* keeping the seed the same will provide a superset of the
* previous barrier set - i.e. if you ask for 10 barriers, and
* then decide that's still too hard and ask for 20, you'll get
* the original 10 plus 10 more, rather than getting 20 new
* ones and the chance of remembering your first 10.)
*/
nbarriers = (int)(params->barrier_probability * count234(barriertree));
assert(nbarriers >= 0 && nbarriers <= count234(barriertree));
while (nbarriers > 0) {
int i;
struct xyd *xyd;
int x1, y1, d1, x2, y2, d2;
/*
* Extract a randomly chosen barrier from the list.
*/
i = random_upto(rs, count234(barriertree));
xyd = delpos234(barriertree, i);
assert(xyd != NULL);
x1 = xyd->x;
y1 = xyd->y;
d1 = xyd->direction;
sfree(xyd);
OFFSET(x2, y2, x1, y1, d1, params);
d2 = F(d1);
index(params, barriers, x1, y1) |= d1;
index(params, barriers, x2, y2) |= d2;
nbarriers--;
}
/*
* Clean up the rest of the barrier list.
*/
{
struct xyd *xyd;
while ( (xyd = delpos234(barriertree, 0)) != NULL)
sfree(xyd);
freetree234(barriertree);
}
/*
* Finally, encode the grid into a string game description.
*
* My syntax is extremely simple: each square is encoded as a
* hex digit in which bit 0 means a connection on the right,
* bit 1 means up, bit 2 left and bit 3 down. (i.e. the same
* encoding as used internally). Each digit is followed by
* optional barrier indicators: `v' means a vertical barrier to
* the right of it, and `h' means a horizontal barrier below
* it.
*/
desc = snewn(w * h * 3 + 1, char);
p = desc;
for (y = 0; y < h; y++) {
for (x = 0; x < w; x++) {
*p++ = "0123456789abcdef"[index(params, tiles, x, y)];
if ((params->wrapping || x < w-1) &&
(index(params, barriers, x, y) & R))
*p++ = 'v';
if ((params->wrapping || y < h-1) &&
(index(params, barriers, x, y) & D))
*p++ = 'h';
}
}
assert(p - desc <= w*h*3);
*p = '\0';
sfree(tiles);
sfree(barriers);
return desc;
}
static const char *validate_desc(const game_params *params, const char *desc)
{
int w = params->width, h = params->height;
int i;
for (i = 0; i < w*h; i++) {
if (*desc >= '0' && *desc <= '9')
/* OK */;
else if (*desc >= 'a' && *desc <= 'f')
/* OK */;
else if (*desc >= 'A' && *desc <= 'F')
/* OK */;
else if (!*desc)
return "Game description shorter than expected";
else
return "Game description contained unexpected character";
desc++;
while (*desc == 'h' || *desc == 'v')
desc++;
}
if (*desc)
return "Game description longer than expected";
return NULL;
}
/* ----------------------------------------------------------------------
* Construct an initial game state, given a description and parameters.
*/
static game_state *new_game(midend *me, const game_params *params,
const char *desc)
{
game_state *state;
int w, h, x, y;
assert(params->width > 0 && params->height > 0);
assert(params->width > 1 || params->height > 1);
/*
* Create a blank game state.
*/
state = snew(game_state);
w = state->width = params->width;
h = state->height = params->height;
state->cx = state->width / 2;
state->cy = state->height / 2;
state->wrapping = params->wrapping;
state->movetarget = params->movetarget;
state->completed = 0;
state->used_solve = false;
state->move_count = 0;
state->last_move_row = -1;
state->last_move_col = -1;
state->last_move_dir = 0;
state->tiles = snewn(state->width * state->height, unsigned char);
memset(state->tiles, 0, state->width * state->height);
state->barriers = snewn(state->width * state->height, unsigned char);
memset(state->barriers, 0, state->width * state->height);
/*
* Parse the game description into the grid.
*/
for (y = 0; y < h; y++) {
for (x = 0; x < w; x++) {
if (*desc >= '0' && *desc <= '9')
tile(state, x, y) = *desc - '0';
else if (*desc >= 'a' && *desc <= 'f')
tile(state, x, y) = *desc - 'a' + 10;
else if (*desc >= 'A' && *desc <= 'F')
tile(state, x, y) = *desc - 'A' + 10;
if (*desc)
desc++;
while (*desc == 'h' || *desc == 'v') {
int x2, y2, d1, d2;
if (*desc == 'v')
d1 = R;
else
d1 = D;
OFFSET(x2, y2, x, y, d1, state);
d2 = F(d1);
barrier(state, x, y) |= d1;
barrier(state, x2, y2) |= d2;
desc++;
}
}
}
/*
* Set up border barriers if this is a non-wrapping game.
*/
if (!state->wrapping) {
for (x = 0; x < state->width; x++) {
barrier(state, x, 0) |= U;
barrier(state, x, state->height-1) |= D;
}
for (y = 0; y < state->height; y++) {
barrier(state, 0, y) |= L;
barrier(state, state->width-1, y) |= R;
}
}
/*
* Set up the barrier corner flags, for drawing barriers
* prettily when they meet.
*/
for (y = 0; y < state->height; y++) {
for (x = 0; x < state->width; x++) {
int dir;
for (dir = 1; dir < 0x10; dir <<= 1) {
int dir2 = A(dir);
int x1, y1, x2, y2, x3, y3;
bool corner = false;
if (!(barrier(state, x, y) & dir))
continue;
if (barrier(state, x, y) & dir2)
corner = true;
x1 = x + X(dir), y1 = y + Y(dir);
if (x1 >= 0 && x1 < state->width &&
y1 >= 0 && y1 < state->height &&
(barrier(state, x1, y1) & dir2))
corner = true;
x2 = x + X(dir2), y2 = y + Y(dir2);
if (x2 >= 0 && x2 < state->width &&
y2 >= 0 && y2 < state->height &&
(barrier(state, x2, y2) & dir))
corner = true;
if (corner) {
barrier(state, x, y) |= (dir << 4);
if (x1 >= 0 && x1 < state->width &&
y1 >= 0 && y1 < state->height)
barrier(state, x1, y1) |= (A(dir) << 4);
if (x2 >= 0 && x2 < state->width &&
y2 >= 0 && y2 < state->height)
barrier(state, x2, y2) |= (C(dir) << 4);
x3 = x + X(dir) + X(dir2), y3 = y + Y(dir) + Y(dir2);
if (x3 >= 0 && x3 < state->width &&
y3 >= 0 && y3 < state->height)
barrier(state, x3, y3) |= (F(dir) << 4);
}
}
}
}
return state;
}
static game_state *dup_game(const game_state *state)
{
game_state *ret;
ret = snew(game_state);
ret->width = state->width;
ret->height = state->height;
ret->cx = state->cx;
ret->cy = state->cy;
ret->wrapping = state->wrapping;
ret->movetarget = state->movetarget;
ret->completed = state->completed;
ret->used_solve = state->used_solve;
ret->move_count = state->move_count;
ret->last_move_row = state->last_move_row;
ret->last_move_col = state->last_move_col;
ret->last_move_dir = state->last_move_dir;
ret->tiles = snewn(state->width * state->height, unsigned char);
memcpy(ret->tiles, state->tiles, state->width * state->height);
ret->barriers = snewn(state->width * state->height, unsigned char);
memcpy(ret->barriers, state->barriers, state->width * state->height);
return ret;
}
static void free_game(game_state *state)
{
sfree(state->tiles);
sfree(state->barriers);
sfree(state);
}
static char *solve_game(const game_state *state, const game_state *currstate,
const char *aux, const char **error)
{
if (!aux) {
*error = "Solution not known for this puzzle";
return NULL;
}
return dupstr(aux);
}
/* ----------------------------------------------------------------------
* Utility routine.
*/
/*
* Compute which squares are reachable from the centre square, as a
* quick visual aid to determining how close the game is to
* completion. This is also a simple way to tell if the game _is_
* completed - just call this function and see whether every square
* is marked active.
*
* squares in the moving_row and moving_col are always inactive - this
* is so that "current" doesn't appear to jump across moving lines.
*/
static unsigned char *compute_active(const game_state *state,
int moving_row, int moving_col)
{
unsigned char *active;
tree234 *todo;
struct xyd *xyd;
active = snewn(state->width * state->height, unsigned char);
memset(active, 0, state->width * state->height);
/*
* We only store (x,y) pairs in todo, but it's easier to reuse
* xyd_cmp and just store direction 0 every time.
*/
todo = newtree234(xyd_cmp);
index(state, active, state->cx, state->cy) = ACTIVE;
add234(todo, new_xyd(state->cx, state->cy, 0));
while ( (xyd = delpos234(todo, 0)) != NULL) {
int x1, y1, d1, x2, y2, d2;
x1 = xyd->x;
y1 = xyd->y;
sfree(xyd);
for (d1 = 1; d1 < 0x10; d1 <<= 1) {
OFFSET(x2, y2, x1, y1, d1, state);
d2 = F(d1);
/*
* If the next tile in this direction is connected to
* us, and there isn't a barrier in the way, and it
* isn't already marked active, then mark it active and
* add it to the to-examine list.
*/
if ((x2 != moving_col && y2 != moving_row) &&
(tile(state, x1, y1) & d1) &&
(tile(state, x2, y2) & d2) &&
!(barrier(state, x1, y1) & d1) &&
!index(state, active, x2, y2)) {
index(state, active, x2, y2) = ACTIVE;
add234(todo, new_xyd(x2, y2, 0));
}
}
}
/* Now we expect the todo list to have shrunk to zero size. */
assert(count234(todo) == 0);
freetree234(todo);
return active;
}
struct game_ui {
int cur_x, cur_y;
bool cur_visible;
};
static game_ui *new_ui(const game_state *state)
{
game_ui *ui = snew(game_ui);
ui->cur_x = 0;
ui->cur_y = -1;
ui->cur_visible = getenv_bool("PUZZLES_SHOW_CURSOR", false);
return ui;
}
static void free_ui(game_ui *ui)
{
sfree(ui);
}
/* ----------------------------------------------------------------------
* Process a move.
*/
static void slide_row_int(int w, int h, unsigned char *tiles, int dir, int row)
{
int x = dir > 0 ? -1 : w;
int tx = x + dir;
int n = w - 1;
unsigned char endtile;
assert(0 <= tx && tx < w);
endtile = tiles[row * w + tx];
do {
x = tx;
tx = (x + dir + w) % w;