ref: 97e93dbfff96e79fb7d5b7f6ae085084c63a9179
parent: aae029926feaa07833dd51e4fb8fbe9f2f19a4e8
author: Simon Tatham <anakin@pobox.com>
date: Mon Jul 4 15:42:55 EDT 2005
Peg Solitaire implementation, complete with a random board generator. The generator is lacking in almost any kind of finesse, but it produces puzzles which at least _I_ find plausibly puzzling. [originally from svn r6052]
--- a/Recipe
+++ b/Recipe
@@ -19,9 +19,10 @@
NETSLIDE = netslide tree234
MINES = mines tree234
FLIP = flip tree234
+PEGS = pegs tree234
ALL = list NET NETSLIDE cube fifteen sixteen rect pattern solo twiddle
- + MINES samegame FLIP guess
+ + MINES samegame FLIP guess PEGS
net : [X] gtk COMMON NET
netslide : [X] gtk COMMON NETSLIDE
@@ -36,6 +37,7 @@
samegame : [X] gtk COMMON samegame
flip : [X] gtk COMMON FLIP
guess : [X] gtk COMMON guess
+pegs : [X] gtk COMMON PEGS
# The Windows Net shouldn't be called `net.exe' since Windows
# already has a reasonably important utility program by that name!
@@ -52,6 +54,7 @@
samegame : [G] WINDOWS COMMON samegame
flip : [G] WINDOWS COMMON FLIP
guess : [G] WINDOWS COMMON guess
+pegs : [G] WINDOWS COMMON PEGS
# Mac OS X unified application containing all the puzzles.
Puzzles : [MX] osx osx.icns osx-info.plist COMMON ALL
--- a/list.c
+++ b/list.c
@@ -25,6 +25,7 @@
extern const game net;
extern const game netslide;
extern const game pattern;
+extern const game pegs;
extern const game rect;
extern const game samegame;
extern const game sixteen;
@@ -40,6 +41,7 @@
&net,
&netslide,
&pattern,
+ &pegs,
&rect,
&samegame,
&sixteen,
--- /dev/null
+++ b/pegs.c
@@ -1,0 +1,1105 @@
+/*
+ * pegs.c: the classic Peg Solitaire game.
+ */
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <assert.h>
+#include <ctype.h>
+#include <math.h>
+
+#include "puzzles.h"
+#include "tree234.h"
+
+#define GRID_HOLE 0
+#define GRID_PEG 1
+#define GRID_OBST 2
+
+enum {+ COL_BACKGROUND,
+ COL_HIGHLIGHT,
+ COL_LOWLIGHT,
+ COL_PEG,
+ NCOLOURS
+};
+
+/*
+ * Grid shapes. I do some macro ickery here to ensure that my enum
+ * and the various forms of my name list always match up.
+ */
+#define TYPELIST(A) \
+ A(CROSS,Cross,cross) \
+ A(OCTAGON,Octagon,octagon) \
+ A(RANDOM,Random,random)
+#define ENUM(upper,title,lower) TYPE_ ## upper,
+#define TITLE(upper,title,lower) #title,
+#define LOWER(upper,title,lower) #lower,
+#define CONFIG(upper,title,lower) ":" #title
+
+enum { TYPELIST(ENUM) TYPECOUNT };+static char const *const pegs_titletypes[] = { TYPELIST(TITLE) };+static char const *const pegs_lowertypes[] = { TYPELIST(LOWER) };+#define TYPECONFIG TYPELIST(CONFIG)
+
+struct game_params {+ int w, h;
+ int type;
+};
+
+struct game_state {+ int w, h;
+ unsigned char *grid;
+};
+
+static game_params *default_params(void)
+{+ game_params *ret = snew(game_params);
+
+ ret->w = ret->h = 7;
+ ret->type = TYPE_CROSS;
+
+ return ret;
+}
+
+static const struct game_params pegs_presets[] = {+ {7, 7, TYPE_CROSS},+ {7, 7, TYPE_OCTAGON},+ {5, 5, TYPE_RANDOM},+ {7, 7, TYPE_RANDOM},+ {9, 9, TYPE_RANDOM},+};
+
+static int game_fetch_preset(int i, char **name, game_params **params)
+{+ game_params *ret;
+ char str[80];
+
+ if (i < 0 || i >= lenof(pegs_presets))
+ return FALSE;
+
+ ret = snew(game_params);
+ *ret = pegs_presets[i];
+
+ strcpy(str, pegs_titletypes[ret->type]);
+ if (ret->type == TYPE_RANDOM)
+ sprintf(str + strlen(str), " %dx%d", ret->w, ret->h);
+
+ *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 *params, char const *string)
+{+ char const *p = string;
+ int i;
+
+ params->w = atoi(p);
+ while (*p && isdigit((unsigned char)*p)) p++;
+ if (*p == 'x') {+ p++;
+ params->h = atoi(p);
+ while (*p && isdigit((unsigned char)*p)) p++;
+ } else {+ params->h = params->w;
+ }
+
+ for (i = 0; i < lenof(pegs_lowertypes); i++)
+ if (!strcmp(p, pegs_lowertypes[i]))
+ params->type = i;
+}
+
+static char *encode_params(game_params *params, int full)
+{+ char str[80];
+
+ sprintf(str, "%dx%d", params->w, params->h);
+ if (full) {+ assert(params->type >= 0 && params->type < lenof(pegs_lowertypes));
+ strcat(str, pegs_lowertypes[params->type]);
+ }
+ return dupstr(str);
+}
+
+static config_item *game_configure(game_params *params)
+{+ config_item *ret = snewn(4, config_item);
+ char buf[80];
+
+ 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 = "Board type";
+ ret[2].type = C_CHOICES;
+ ret[2].sval = TYPECONFIG;
+ ret[2].ival = params->type;
+
+ 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->type = cfg[2].ival;
+
+ return ret;
+}
+
+static char *validate_params(game_params *params)
+{+ if (params->w <= 3 || params->h <= 3)
+ return "Width and height must both be greater than three";
+
+ /*
+ * It might be possible to implement generalisations of Cross
+ * and Octagon, but only if I can find a proof that they're all
+ * soluble. For the moment, therefore, I'm going to disallow
+ * them at any size other than the standard one.
+ */
+ if (params->type == TYPE_CROSS || params->type == TYPE_OCTAGON) {+ if (params->w != 7 || params->h != 7)
+ return "This board type is only supported at 7x7";
+ }
+ return NULL;
+}
+
+/* ----------------------------------------------------------------------
+ * Beginning of code to generate random Peg Solitaire boards.
+ *
+ * This procedure is done with no aesthetic judgment, no effort at
+ * symmetry, no difficulty grading and generally no finesse
+ * whatsoever. We simply begin with an empty board containing a
+ * single peg, and repeatedly make random reverse moves until it's
+ * plausibly full. This typically yields a scrappy haphazard mess
+ * with several holes, an uneven shape, and no redeeming features
+ * except guaranteed solubility.
+ *
+ * My only concessions to sophistication are (a) to repeat the
+ * generation process until I at least get a grid that touches
+ * every edge of the specified board size, and (b) to try when
+ * selecting moves to reuse existing space rather than expanding
+ * into new space (so that non-rectangular board shape becomes a
+ * factor during play).
+ */
+
+struct move {+ /*
+ * x,y are the start point of the move during generation (hence
+ * its endpoint during normal play).
+ *
+ * dx,dy are the direction of the move during generation.
+ * Absolute value 1. Hence, for example, x=3,y=5,dx=1,dy=0
+ * means that the move during generation starts at (3,5) and
+ * ends at (5,5), and vice versa during normal play.
+ */
+ int x, y, dx, dy;
+ /*
+ * cost is 0, 1 or 2, depending on how many GRID_OBSTs we must
+ * turn into GRID_HOLEs to play this move.
+ */
+ int cost;
+};
+
+static int movecmp(void *av, void *bv)
+{+ struct move *a = (struct move *)av;
+ struct move *b = (struct move *)bv;
+
+ if (a->y < b->y)
+ return -1;
+ else if (a->y > b->y)
+ return +1;
+
+ if (a->x < b->x)
+ return -1;
+ else if (a->x > b->x)
+ return +1;
+
+ if (a->dy < b->dy)
+ return -1;
+ else if (a->dy > b->dy)
+ return +1;
+
+ if (a->dx < b->dx)
+ return -1;
+ else if (a->dx > b->dx)
+ return +1;
+
+ return 0;
+}
+
+static int movecmpcost(void *av, void *bv)
+{+ struct move *a = (struct move *)av;
+ struct move *b = (struct move *)bv;
+
+ if (a->cost < b->cost)
+ return -1;
+ else if (a->cost > b->cost)
+ return +1;
+
+ return movecmp(av, bv);
+}
+
+struct movetrees {+ tree234 *bymove, *bycost;
+};
+
+static void update_moves(unsigned char *grid, int w, int h, int x, int y,
+ struct movetrees *trees)
+{+ struct move move;
+ int dir, pos;
+
+ /*
+ * There are twelve moves that can include (x,y): three in each
+ * of four directions. Check each one to see if it's possible.
+ */
+ for (dir = 0; dir < 4; dir++) {+ int dx, dy;
+
+ if (dir & 1)
+ dx = 0, dy = dir - 2;
+ else
+ dy = 0, dx = dir - 1;
+
+ assert(abs(dx) + abs(dy) == 1);
+
+ for (pos = 0; pos < 3; pos++) {+ int v1, v2, v3;
+
+ move.dx = dx;
+ move.dy = dy;
+ move.x = x - pos*dx;
+ move.y = y - pos*dy;
+
+ if (move.x < 0 || move.x >= w || move.y < 0 || move.y >= h)
+ continue; /* completely invalid move */
+ if (move.x+2*move.dx < 0 || move.x+2*move.dx >= w ||
+ move.y+2*move.dy < 0 || move.y+2*move.dy >= h)
+ continue; /* completely invalid move */
+
+ v1 = grid[move.y * w + move.x];
+ v2 = grid[(move.y+move.dy) * w + (move.x+move.dx)];
+ v3 = grid[(move.y+2*move.dy)*w + (move.x+2*move.dx)];
+ if (v1 == GRID_PEG && v2 != GRID_PEG && v3 != GRID_PEG) {+ struct move *m;
+
+ move.cost = (v2 == GRID_OBST) + (v3 == GRID_OBST);
+
+ /*
+ * This move is possible. See if it's already in
+ * the tree.
+ */
+ m = find234(trees->bymove, &move, NULL);
+ if (m && m->cost != move.cost) {+ /*
+ * It's in the tree but listed with the wrong
+ * cost. Remove the old version.
+ */
+#ifdef GENERATION_DIAGNOSTICS
+ printf("correcting %d%+d,%d%+d at cost %d\n",+ m->x, m->dx, m->y, m->dy, m->cost);
+#endif
+ del234(trees->bymove, m);
+ del234(trees->bycost, m);
+ sfree(m);
+ m = NULL;
+ }
+ if (!m) {+ struct move *m, *m2;
+ m = snew(struct move);
+ *m = move;
+ m2 = add234(trees->bymove, m);
+ m2 = add234(trees->bycost, m);
+ assert(m2 == m);
+#ifdef GENERATION_DIAGNOSTICS
+ printf("adding %d%+d,%d%+d at cost %d\n",+ move.x, move.dx, move.y, move.dy, move.cost);
+#endif
+ } else {+#ifdef GENERATION_DIAGNOSTICS
+ printf("not adding %d%+d,%d%+d at cost %d\n",+ move.x, move.dx, move.y, move.dy, move.cost);
+#endif
+ }
+ } else {+ /*
+ * This move is impossible. If it is already in the
+ * tree, delete it.
+ *
+ * (We make use here of the fact that del234
+ * doesn't have to be passed a pointer to the
+ * _actual_ element it's deleting: it merely needs
+ * one that compares equal to it, and it will
+ * return the one it deletes.)
+ */
+ struct move *m = del234(trees->bymove, &move);
+#ifdef GENERATION_DIAGNOSTICS
+ printf("%sdeleting %d%+d,%d%+d\n", m ? "" : "not ",+ move.x, move.dx, move.y, move.dy);
+#endif
+ if (m) {+ del234(trees->bycost, m);
+ sfree(m);
+ }
+ }
+ }
+ }
+}
+
+static void pegs_genmoves(unsigned char *grid, int w, int h, random_state *rs)
+{+ struct movetrees atrees, *trees = &atrees;
+ struct move *m;
+ int x, y, i, nmoves;
+
+ trees->bymove = newtree234(movecmp);
+ trees->bycost = newtree234(movecmpcost);
+
+ for (y = 0; y < h; y++)
+ for (x = 0; x < w; x++)
+ if (grid[y*w+x] == GRID_PEG)
+ update_moves(grid, w, h, x, y, trees);
+
+ nmoves = 0;
+
+ while (1) {+ int limit, maxcost, index;
+ struct move mtmp, move, *m;
+
+ /*
+ * See how many moves we can make at zero cost. Make one,
+ * if possible. Failing that, make a one-cost move, and
+ * then a two-cost one.
+ *
+ * After filling at least half the input grid, we no longer
+ * accept cost-2 moves: if that's our only option, we give
+ * up and finish.
+ */
+ mtmp.y = h+1;
+ maxcost = (nmoves < w*h/2 ? 2 : 1);
+ m = NULL; /* placate optimiser */
+ for (mtmp.cost = 0; mtmp.cost <= maxcost; mtmp.cost++) {+ limit = -1;
+ m = findrelpos234(trees->bycost, &mtmp, NULL, REL234_LT, &limit);
+#ifdef GENERATION_DIAGNOSTICS
+ printf("%d moves available with cost %d\n", limit+1, mtmp.cost);+#endif
+ if (m)
+ break;
+ }
+ if (!m)
+ break;
+
+ index = random_upto(rs, limit+1);
+ move = *(struct move *)index234(trees->bycost, index);
+
+#ifdef GENERATION_DIAGNOSTICS
+ printf("selecting move %d%+d,%d%+d at cost %d\n",+ move.x, move.dx, move.y, move.dy, move.cost);
+#endif
+
+ grid[move.y * w + move.x] = GRID_HOLE;
+ grid[(move.y+move.dy) * w + (move.x+move.dx)] = GRID_PEG;
+ grid[(move.y+2*move.dy)*w + (move.x+2*move.dx)] = GRID_PEG;
+
+ for (i = 0; i <= 2; i++) {+ int tx = move.x + i*move.dx;
+ int ty = move.y + i*move.dy;
+ update_moves(grid, w, h, tx, ty, trees);
+ }
+
+ nmoves++;
+ }
+
+ while ((m = delpos234(trees->bymove, 0)) != NULL) {+ del234(trees->bycost, m);
+ sfree(m);
+ }
+ freetree234(trees->bymove);
+ freetree234(trees->bycost);
+}
+
+static void pegs_generate(unsigned char *grid, int w, int h, random_state *rs)
+{+ while (1) {+ int x, y, extremes;
+
+ memset(grid, GRID_OBST, w*h);
+ grid[(h/2) * w + (w/2)] = GRID_PEG;
+#ifdef GENERATION_DIAGNOSTICS
+ printf("beginning move selection\n");+#endif
+ pegs_genmoves(grid, w, h, rs);
+#ifdef GENERATION_DIAGNOSTICS
+ printf("finished move selection\n");+#endif
+
+ extremes = 0;
+ for (y = 0; y < h; y++) {+ if (grid[y*w+0] != GRID_OBST)
+ extremes |= 1;
+ if (grid[y*w+w-1] != GRID_OBST)
+ extremes |= 2;
+ }
+ for (x = 0; x < w; x++) {+ if (grid[0*w+x] != GRID_OBST)
+ extremes |= 4;
+ if (grid[(h-1)*w+x] != GRID_OBST)
+ extremes |= 8;
+ }
+
+ if (extremes == 15)
+ break;
+#ifdef GENERATION_DIAGNOSTICS
+ printf("insufficient extent; trying again\n");+#endif
+ }
+ fflush(stdout);
+}
+
+/* ----------------------------------------------------------------------
+ * End of board generation code. Now for the client code which uses
+ * it as part of the puzzle.
+ */
+
+static char *new_game_desc(game_params *params, random_state *rs,
+ char **aux, int interactive)
+{+ int w = params->w, h = params->h;
+ unsigned char *grid;
+ char *ret;
+ int i;
+
+ grid = snewn(w*h, unsigned char);
+ if (params->type == TYPE_RANDOM) {+ pegs_generate(grid, w, h, rs);
+ } else {+ int x, y, cx, cy, v;
+
+ for (y = 0; y < h; y++)
+ for (x = 0; x < w; x++) {+ v = GRID_OBST; /* placate optimiser */
+ switch (params->type) {+ case TYPE_CROSS:
+ cx = abs(x - w/2);
+ cy = abs(y - h/2);
+ if (cx == 0 && cy == 0)
+ v = GRID_HOLE;
+ else if (cx > 1 && cy > 1)
+ v = GRID_OBST;
+ else
+ v = GRID_PEG;
+ break;
+ case TYPE_OCTAGON:
+ cx = abs(x - w/2);
+ cy = abs(y - h/2);
+ if (cx == 0 && cy == 0)
+ v = GRID_HOLE;
+ else if (cx + cy > 1 + max(w,h)/2)
+ v = GRID_OBST;
+ else
+ v = GRID_PEG;
+ break;
+ }
+ grid[y*w+x] = v;
+ }
+ }
+
+ /*
+ * Encode a game description which is simply a long list of P
+ * for peg, H for hole or O for obstacle.
+ */
+ ret = snewn(w*h+1, char);
+ for (i = 0; i < w*h; i++)
+ ret[i] = (grid[i] == GRID_PEG ? 'P' :
+ grid[i] == GRID_HOLE ? 'H' : 'O');
+ ret[w*h] = '\0';
+
+ sfree(grid);
+
+ return ret;
+}
+
+static char *validate_desc(game_params *params, char *desc)
+{+ int len = params->w * params->h;
+
+ if (len != strlen(desc))
+ return "Game description is wrong length";
+ if (len != strspn(desc, "PHO"))
+ return "Invalid character in game description";
+
+ return NULL;
+}
+
+static game_state *new_game(midend_data *me, game_params *params, char *desc)
+{+ int w = params->w, h = params->h;
+ game_state *state = snew(game_state);
+ int i;
+
+ state->w = w;
+ state->h = h;
+ state->grid = snewn(w*h, unsigned char);
+ for (i = 0; i < w*h; i++)
+ state->grid[i] = (desc[i] == 'P' ? GRID_PEG :
+ desc[i] == 'H' ? GRID_HOLE : GRID_OBST);
+
+ return state;
+}
+
+static game_state *dup_game(game_state *state)
+{+ int w = state->w, h = state->h;
+ game_state *ret = snew(game_state);
+
+ ret->w = state->w;
+ ret->h = state->h;
+ ret->grid = snewn(w*h, unsigned char);
+ memcpy(ret->grid, state->grid, w*h);
+
+ return ret;
+}
+
+static void free_game(game_state *state)
+{+ sfree(state->grid);
+ sfree(state);
+}
+
+static char *solve_game(game_state *state, game_state *currstate,
+ char *aux, char **error)
+{+ return NULL;
+}
+
+static char *game_text_format(game_state *state)
+{+ int w = state->w, h = state->h;
+ int x, y;
+ char *ret;
+
+ ret = snewn((w+1)*h + 1, char);
+
+ for (y = 0; y < h; y++) {+ for (x = 0; x < w; x++)
+ ret[y*(w+1)+x] = (state->grid[y*w+x] == GRID_HOLE ? '-' :
+ state->grid[y*w+x] == GRID_PEG ? '*' : ' ');
+ ret[y*(w+1)+w] = '\n';
+ }
+ ret[h*(w+1)] = '\0';
+
+ return ret;
+}
+
+struct game_ui {+ int dragging; /* boolean: is a drag in progress? */
+ int sx, sy; /* grid coords of drag start cell */
+ int dx, dy; /* pixel coords of current drag posn */
+};
+
+static game_ui *new_ui(game_state *state)
+{+ game_ui *ui = snew(game_ui);
+
+ ui->sx = ui->sy = ui->dx = ui->dy = 0;
+ ui->dragging = FALSE;
+
+ return ui;
+}
+
+static void free_ui(game_ui *ui)
+{+ sfree(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)
+{+ /*
+ * Cancel a drag, in case the source square has become
+ * unoccupied.
+ */
+ ui->dragging = FALSE;
+}
+
+#define PREFERRED_TILE_SIZE 33
+#define TILESIZE (ds->tilesize)
+#define BORDER (TILESIZE / 2)
+
+#define HIGHLIGHT_WIDTH (TILESIZE / 16)
+
+#define COORD(x) ( BORDER + (x) * TILESIZE )
+#define FROMCOORD(x) ( ((x) + TILESIZE - BORDER) / TILESIZE - 1 )
+
+struct game_drawstate {+ int tilesize;
+ blitter *drag_background;
+ int dragging, dragx, dragy;
+ int w, h;
+ unsigned char *grid;
+ int started;
+};
+
+static char *interpret_move(game_state *state, game_ui *ui, game_drawstate *ds,
+ int x, int y, int button)
+{+ int w = state->w, h = state->h;
+
+ if (button == LEFT_BUTTON) {+ int tx, ty;
+
+ /*
+ * Left button down: we attempt to start a drag.
+ */
+
+ /*
+ * There certainly shouldn't be a current drag in progress,
+ * unless the midend failed to send us button events in
+ * order; it has a responsibility to always get that right,
+ * so we can legitimately punish it by failing an
+ * assertion.
+ */
+ assert(!ui->dragging);
+
+ tx = FROMCOORD(x);
+ ty = FROMCOORD(y);
+ if (tx >= 0 && tx < w && ty >= 0 && ty < h &&
+ state->grid[ty*w+tx] == GRID_PEG) {+ ui->dragging = TRUE;
+ ui->sx = tx;
+ ui->sy = ty;
+ ui->dx = x;
+ ui->dy = y;
+ return ""; /* ui modified */
+ }
+ } else if (button == LEFT_DRAG && ui->dragging) {+ /*
+ * Mouse moved; just move the peg being dragged.
+ */
+ ui->dx = x;
+ ui->dy = y;
+ return ""; /* ui modified */
+ } else if (button == LEFT_RELEASE && ui->dragging) {+ char buf[80];
+ int tx, ty, dx, dy;
+
+ /*
+ * Button released. Identify the target square of the drag,
+ * see if it represents a valid move, and if so make it.
+ */
+ ui->dragging = FALSE; /* cancel the drag no matter what */
+ tx = FROMCOORD(x);
+ ty = FROMCOORD(y);
+ if (tx < 0 || tx >= w || ty < 0 || ty >= h)
+ return ""; /* target out of range */
+ dx = tx - ui->sx;
+ dy = ty - ui->sy;
+ if (max(abs(dx),abs(dy)) != 2 || min(abs(dx),abs(dy)) != 0)
+ return ""; /* move length was wrong */
+ dx /= 2;
+ dy /= 2;
+
+ if (state->grid[ty*w+tx] != GRID_HOLE ||
+ state->grid[(ty-dy)*w+(tx-dx)] != GRID_PEG ||
+ state->grid[ui->sy*w+ui->sx] != GRID_PEG)
+ return ""; /* grid contents were invalid */
+
+ /*
+ * We have a valid move. Encode it simply as source and
+ * destination coordinate pairs.
+ */
+ sprintf(buf, "%d,%d-%d,%d", ui->sx, ui->sy, tx, ty);
+ return dupstr(buf);
+ }
+ return NULL;
+}
+
+static game_state *execute_move(game_state *state, char *move)
+{+ int w = state->w, h = state->h;
+ int sx, sy, tx, ty;
+ game_state *ret;
+
+ if (sscanf(move, "%d,%d-%d,%d", &sx, &sy, &tx, &ty)) {+ int mx, my, dx, dy;
+
+ if (sx < 0 || sx >= w || sy < 0 || sy >= h)
+ return NULL; /* source out of range */
+ if (tx < 0 || tx >= w || ty < 0 || ty >= h)
+ return NULL; /* target out of range */
+
+ dx = tx - sx;
+ dy = ty - sy;
+ if (max(abs(dx),abs(dy)) != 2 || min(abs(dx),abs(dy)) != 0)
+ return NULL; /* move length was wrong */
+ mx = sx + dx/2;
+ my = sy + dy/2;
+
+ if (state->grid[sy*w+sx] != GRID_PEG ||
+ state->grid[my*w+mx] != GRID_PEG ||
+ state->grid[ty*w+tx] != GRID_HOLE)
+ return NULL; /* grid contents were invalid */
+
+ ret = dup_game(state);
+ ret->grid[sy*w+sx] = GRID_HOLE;
+ ret->grid[my*w+mx] = GRID_HOLE;
+ ret->grid[ty*w+tx] = GRID_PEG;
+
+ return ret;
+ }
+ return NULL;
+}
+
+/* ----------------------------------------------------------------------
+ * Drawing routines.
+ */
+
+static void game_size(game_params *params, game_drawstate *ds,
+ int *x, int *y, int expand)
+{+ double tsx, tsy, ts;
+ /*
+ * Each window dimension equals the tile size times one more
+ * than the grid dimension (the border is half the width of the
+ * tiles).
+ */
+ tsx = (double)*x / ((double)params->w + 1.0);
+ tsy = (double)*y / ((double)params->h + 1.0);
+ ts = min(tsx, tsy);
+ if (expand)
+ ds->tilesize = (int)(ts + 0.5);
+ else
+ ds->tilesize = min((int)ts, PREFERRED_TILE_SIZE);
+
+ *x = TILESIZE * params->w + 2 * BORDER;
+ *y = TILESIZE * params->h + 2 * BORDER;
+
+ if (ds->drag_background)
+ blitter_free(ds->drag_background);
+ ds->drag_background = blitter_new(TILESIZE, TILESIZE);
+}
+
+static float *game_colours(frontend *fe, game_state *state, int *ncolours)
+{+ float *ret = snewn(3 * NCOLOURS, float);
+ int i;
+ float max;
+
+ frontend_default_colour(fe, &ret[COL_BACKGROUND * 3]);
+
+ /*
+ * Drop the background colour so that the highlight is
+ * noticeably brighter than it while still being under 1.
+ */
+ max = ret[COL_BACKGROUND*3];
+ for (i = 1; i < 3; i++)
+ if (ret[COL_BACKGROUND*3+i] > max)
+ max = ret[COL_BACKGROUND*3+i];
+ if (max * 1.2F > 1.0F) {+ for (i = 0; i < 3; i++)
+ ret[COL_BACKGROUND*3+i] /= (max * 1.2F);
+ }
+
+ for (i = 0; i < 3; i++) {+ ret[COL_HIGHLIGHT * 3 + i] = ret[COL_BACKGROUND * 3 + i] * 1.2F;
+ ret[COL_LOWLIGHT * 3 + i] = ret[COL_BACKGROUND * 3 + i] * 0.8F;
+ }
+
+ ret[COL_PEG * 3 + 0] = 0.0F;
+ ret[COL_PEG * 3 + 1] = 0.0F;
+ ret[COL_PEG * 3 + 2] = 1.0F;
+
+ *ncolours = NCOLOURS;
+ return ret;
+}
+
+static game_drawstate *game_new_drawstate(game_state *state)
+{+ int w = state->w, h = state->h;
+ struct game_drawstate *ds = snew(struct game_drawstate);
+
+ ds->tilesize = 0; /* not decided yet */
+
+ /* We can't allocate the blitter rectangle for the drag background
+ * until we know what size to make it. */
+ ds->drag_background = NULL;
+ ds->dragging = FALSE;
+
+ ds->w = w;
+ ds->h = h;
+ ds->grid = snewn(w*h, unsigned char);
+ memset(ds->grid, 255, w*h);
+
+ ds->started = FALSE;
+
+ return ds;
+}
+
+static void game_free_drawstate(game_drawstate *ds)
+{+ if (ds->drag_background)
+ blitter_free(ds->drag_background);
+ sfree(ds->grid);
+ sfree(ds);
+}
+
+static void draw_tile(frontend *fe, game_drawstate *ds,
+ int x, int y, int v, int erasebg)
+{+ if (erasebg) {+ draw_rect(fe, x, y, TILESIZE, TILESIZE, COL_BACKGROUND);
+ }
+
+ if (v == GRID_HOLE) {+ draw_circle(fe, x+TILESIZE/2, y+TILESIZE/2, TILESIZE/4,
+ COL_LOWLIGHT, COL_LOWLIGHT);
+ } else if (v == GRID_PEG) {+ draw_circle(fe, x+TILESIZE/2, y+TILESIZE/2, TILESIZE/3,
+ COL_PEG, COL_PEG);
+ }
+
+ draw_update(fe, x, y, TILESIZE, TILESIZE);
+}
+
+static void game_redraw(frontend *fe, game_drawstate *ds, game_state *oldstate,
+ game_state *state, int dir, game_ui *ui,
+ float animtime, float flashtime)
+{+ int w = state->w, h = state->h;
+ int x, y;
+
+ /*
+ * Erase the sprite currently being dragged, if any.
+ */
+ if (ds->dragging) {+ assert(ds->drag_background);
+ blitter_load(fe, ds->drag_background, ds->dragx, ds->dragy);
+ draw_update(fe, ds->dragx, ds->dragy, TILESIZE, TILESIZE);
+ ds->dragging = FALSE;
+ }
+
+ if (!ds->started) {+ draw_rect(fe, 0, 0,
+ TILESIZE * state->w + 2 * BORDER,
+ TILESIZE * state->h + 2 * BORDER, COL_BACKGROUND);
+
+ /*
+ * Draw relief marks around all the squares that aren't
+ * GRID_OBST.
+ */
+ for (y = 0; y < h; y++)
+ for (x = 0; x < w; x++)
+ if (state->grid[y*w+x] != GRID_OBST) {+ /*
+ * First pass: draw the full relief square.
+ */
+ int coords[6];
+ coords[0] = COORD(x+1) + HIGHLIGHT_WIDTH - 1;
+ coords[1] = COORD(y) - HIGHLIGHT_WIDTH;
+ coords[2] = COORD(x) - HIGHLIGHT_WIDTH;
+ coords[3] = COORD(y+1) + HIGHLIGHT_WIDTH - 1;
+ coords[4] = COORD(x) - HIGHLIGHT_WIDTH;
+ coords[5] = COORD(y) - HIGHLIGHT_WIDTH;
+ draw_polygon(fe, coords, 3, COL_HIGHLIGHT, COL_HIGHLIGHT);
+ coords[4] = COORD(x+1) + HIGHLIGHT_WIDTH - 1;
+ coords[5] = COORD(y+1) + HIGHLIGHT_WIDTH - 1;
+ draw_polygon(fe, coords, 3, COL_LOWLIGHT, COL_LOWLIGHT);
+ }
+ for (y = 0; y < h; y++)
+ for (x = 0; x < w; x++)
+ if (state->grid[y*w+x] != GRID_OBST) {+ /*
+ * Second pass: draw everything but the two
+ * diagonal corners.
+ */
+ draw_rect(fe, COORD(x) - HIGHLIGHT_WIDTH,
+ COORD(y) - HIGHLIGHT_WIDTH,
+ TILESIZE + HIGHLIGHT_WIDTH,
+ TILESIZE + HIGHLIGHT_WIDTH, COL_HIGHLIGHT);
+ draw_rect(fe, COORD(x),
+ COORD(y),
+ TILESIZE + HIGHLIGHT_WIDTH,
+ TILESIZE + HIGHLIGHT_WIDTH, COL_LOWLIGHT);
+ }
+ for (y = 0; y < h; y++)
+ for (x = 0; x < w; x++)
+ if (state->grid[y*w+x] != GRID_OBST) {+ /*
+ * Third pass: draw a trapezium on each edge.
+ */
+ int coords[8];
+ int dx, dy, s, sn, c;
+
+ for (dx = 0; dx < 2; dx++) {+ dy = 1 - dx;
+ for (s = 0; s < 2; s++) {+ sn = 2*s - 1;
+ c = s ? COL_LOWLIGHT : COL_HIGHLIGHT;
+
+ coords[0] = COORD(x) + (s*dx)*(TILESIZE-1);
+ coords[1] = COORD(y) + (s*dy)*(TILESIZE-1);
+ coords[2] = COORD(x) + (s*dx+dy)*(TILESIZE-1);
+ coords[3] = COORD(y) + (s*dy+dx)*(TILESIZE-1);
+ coords[4] = coords[2] - HIGHLIGHT_WIDTH * (dy-sn*dx);
+ coords[5] = coords[3] - HIGHLIGHT_WIDTH * (dx-sn*dy);
+ coords[6] = coords[0] + HIGHLIGHT_WIDTH * (dy+sn*dx);
+ coords[7] = coords[1] + HIGHLIGHT_WIDTH * (dx+sn*dy);
+ draw_polygon(fe, coords, 4, c, c);
+ }
+ }
+ }
+ for (y = 0; y < h; y++)
+ for (x = 0; x < w; x++)
+ if (state->grid[y*w+x] != GRID_OBST) {+ /*
+ * Second pass: draw everything but the two
+ * diagonal corners.
+ */
+ draw_rect(fe, COORD(x),
+ COORD(y),
+ TILESIZE,
+ TILESIZE, COL_BACKGROUND);
+ }
+
+ ds->started = TRUE;
+
+ draw_update(fe, 0, 0,
+ TILESIZE * state->w + 2 * BORDER,
+ TILESIZE * state->h + 2 * BORDER);
+ }
+
+ /*
+ * Loop over the grid redrawing anything that looks as if it
+ * needs it.
+ */
+ for (y = 0; y < h; y++)
+ for (x = 0; x < w; x++) {+ int v;
+
+ v = state->grid[y*w+x];
+ /*
+ * Blank the source of a drag so it looks as if the
+ * user picked the peg up physically.
+ */
+ if (ui->dragging && ui->sx == x && ui->sy == y && v == GRID_PEG)
+ v = GRID_HOLE;
+ if (v != ds->grid[y*w+x] && v != GRID_OBST) {+ draw_tile(fe, ds, COORD(x), COORD(y), v, TRUE);
+ }
+ }
+
+ /*
+ * Draw the dragging sprite if any.
+ */
+ if (ui->dragging) {+ ds->dragging = TRUE;
+ ds->dragx = ui->dx - TILESIZE/2;
+ ds->dragy = ui->dy - TILESIZE/2;
+ blitter_save(fe, ds->drag_background, ds->dragx, ds->dragy);
+ draw_tile(fe, ds, ds->dragx, ds->dragy, GRID_PEG, FALSE);
+ }
+}
+
+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)
+{+ return 0.0F;
+}
+
+static int game_wants_statusbar(void)
+{+ return FALSE;
+}
+
+static int game_timing_state(game_state *state)
+{+ return TRUE;
+}
+
+#ifdef COMBINED
+#define thegame pegs
+#endif
+
+const struct game thegame = {+ "Pegs", NULL,
+ 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,
+ FALSE, solve_game,
+ TRUE, game_text_format,
+ new_ui,
+ free_ui,
+ encode_ui,
+ decode_ui,
+ game_changed_state,
+ interpret_move,
+ execute_move,
+ game_size,
+ game_colours,
+ game_new_drawstate,
+ game_free_drawstate,
+ game_redraw,
+ game_anim_length,
+ game_flash_length,
+ game_wants_statusbar,
+ FALSE, game_timing_state,
+ 0, /* mouse_priorities */
+};