`Fifteen' was getting the parity wrong on any size of board where

[sgt/puzzles] / fifteen.c

diff --git a/fifteen.c b/fifteen.c
index b3285e7..04a8f75 100644 (file)
--- a/fifteen.c
+++ b/fifteen.c
@@ -11,6 +11,7 @@
 #include "puzzles.h"
 
 const char *const game_name = "Fifteen";
+const int game_can_configure = TRUE;
 
 #define TILE_SIZE 48
 #define BORDER    (TILE_SIZE / 2)
@@ -71,6 +72,51 @@ game_params *dup_params(game_params *params)
     return ret;
 }
 
+config_item *game_configure(game_params *params)
+{
+    config_item *ret;
+    char buf[80];
+
+    ret = snewn(3, 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 = NULL;
+    ret[2].type = C_END;
+    ret[2].sval = NULL;
+    ret[2].ival = 0;
+
+    return ret;
+}
+
+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);
+
+    return ret;
+}
+
+char *validate_params(game_params *params)
+{
+    if (params->w < 2 && params->h < 2)
+       return "Width and height must both be at least two";
+
+    return NULL;
+}
+
 int perm_parity(int *perm, int n)
 {
     int i, j, ret;
@@ -153,15 +199,16 @@ char *new_game_seed(game_params *params)
      * Determine the required parity of the overall permutation.
      * This is the XOR of:
      * 
-     *  - The chessboard parity ((x^y)&1) of the gap square. The
-     *    bottom right, and therefore also the top left, count as
-     *    even.
+     *         - The chessboard parity ((x^y)&1) of the gap square. The
+     *           bottom right counts as even.
      * 
      *  - The parity of n. (The target permutation is 1,...,n-1,0
      *    rather than 0,...,n-1; this is a cyclic permutation of
      *    the starting point and hence is odd iff n is even.)
      */
-    parity = (X(params, gap) ^ Y(params, gap) ^ (n+1)) & 1;
+    parity = ((X(params, gap) - (params->w-1)) ^
+             (Y(params, gap) - (params->h-1)) ^
+             (n+1)) & 1;
 
     /*
      * Try the last two tiles one way round. If that fails, swap
@@ -554,6 +601,13 @@ void game_redraw(frontend *fe, game_drawstate *ds, game_state *oldstate,
     {
        char statusbuf[256];
 
+        /*
+         * Don't show the new status until we're also showing the
+         * new _state_ - after the game animation is complete.
+         */
+        if (oldstate)
+            state = oldstate;
+
        sprintf(statusbuf, "%sMoves: %d",
                (state->completed ? "COMPLETED! " : ""),
                (state->completed ? state->completed : state->movecount));