After discussion with Simon, the game redraw functions are now passed a new
[sgt/puzzles] / rect.c
diff --git a/rect.c b/rect.c
index 0d71226..b9d7cda 100644 (file)
--- a/rect.c
+++ b/rect.c
  *    selection to produce a few large rectangles more often
  *    than oodles of small ones? Unsure, but might be worth a
  *    try.
- * 
- *  - During redraw, do corner analysis centrally in game_redraw()
- *    itself so that we can take it into account when computing the
- *    `visible' array. If we can do this, we can actually _turn on_
- *    the `visible' processing and keep redraws to the minimum
- *    required.
  */
 
 #include <stdio.h>
 #include <stdlib.h>
 #include <string.h>
 #include <assert.h>
+#include <ctype.h>
 #include <math.h>
 
 #include "puzzles.h"
 
 const char *const game_name = "Rectangles";
+const char *const game_winhelp_topic = "games.rectangles";
 const int game_can_configure = TRUE;
 
 enum {
@@ -59,6 +55,7 @@ enum {
 
 struct game_params {
     int w, h;
+    float expandfactor;
 };
 
 #define INDEX(state, x, y)    (((y) * (state)->w) + (x))
@@ -97,6 +94,7 @@ game_params *default_params(void)
     game_params *ret = snew(game_params);
 
     ret->w = ret->h = 7;
+    ret->expandfactor = 0.0F;
 
     return ret;
 }
@@ -120,6 +118,7 @@ int game_fetch_preset(int i, char **name, game_params **params)
     *params = ret = snew(game_params);
     ret->w = w;
     ret->h = h;
+    ret->expandfactor = 0.0F;
     return TRUE;
 }
 
@@ -135,6 +134,35 @@ game_params *dup_params(game_params *params)
     return ret;
 }
 
+game_params *decode_params(char const *string)
+{
+    game_params *ret = default_params();
+
+    ret->w = ret->h = atoi(string);
+    ret->expandfactor = 0.0F;
+    while (*string && isdigit((unsigned char)*string)) string++;
+    if (*string == 'x') {
+        string++;
+        ret->h = atoi(string);
+       while (*string && isdigit((unsigned char)*string)) string++;
+    }
+    if (*string == 'e') {
+       string++;
+       ret->expandfactor = atof(string);
+    }
+
+    return ret;
+}
+
+char *encode_params(game_params *params)
+{
+    char data[256];
+
+    sprintf(data, "%dx%d", params->w, params->h);
+
+    return dupstr(data);
+}
+
 config_item *game_configure(game_params *params)
 {
     config_item *ret;
@@ -154,11 +182,17 @@ config_item *game_configure(game_params *params)
     ret[1].sval = dupstr(buf);
     ret[1].ival = 0;
 
-    ret[2].name = NULL;
-    ret[2].type = C_END;
-    ret[2].sval = NULL;
+    ret[2].name = "Expansion factor";
+    ret[2].type = C_STRING;
+    sprintf(buf, "%g", params->expandfactor);
+    ret[2].sval = dupstr(buf);
     ret[2].ival = 0;
 
+    ret[3].name = NULL;
+    ret[3].type = C_END;
+    ret[3].sval = NULL;
+    ret[3].ival = 0;
+
     return ret;
 }
 
@@ -168,6 +202,7 @@ game_params *custom_params(config_item *cfg)
 
     ret->w = atoi(cfg[0].sval);
     ret->h = atoi(cfg[1].sval);
+    ret->expandfactor = atof(cfg[2].sval);
 
     return ret;
 }
@@ -178,6 +213,8 @@ char *validate_params(game_params *params)
        return "Width and height must both be greater than zero";
     if (params->w < 2 && params->h < 2)
        return "Grid area must be greater than one";
+    if (params->expandfactor < 0.0F)
+       return "Expansion factor may not be negative";
     return NULL;
 }
 
@@ -216,25 +253,6 @@ static struct rectlist *get_rectlist(game_params *params, int *grid)
                 continue;
             for (x = 0; x <= params->w - rw; x++)
                 for (y = 0; y <= params->h - rh; y++) {
-                    /*
-                     * We have a candidate rectangle placement. See
-                     * if it's unobstructed.
-                     */
-                    int xx, yy;
-                    int ok;
-
-                    ok = TRUE;
-                    for (xx = x; xx < x+rw; xx++)
-                        for (yy = y; yy < y+rh; yy++)
-                            if (index(params, grid, xx, yy) >= 0) {
-                                ok = FALSE;
-                                goto break1;   /* break both loops at once */
-                            }
-                    break1:
-
-                    if (!ok)
-                        continue;
-
                     if (nrects >= rectsize) {
                         rectsize = nrects + 256;
                         rects = sresize(rects, rectsize, struct rect);
@@ -320,14 +338,15 @@ static struct rect find_rect(game_params *params, int *grid, int x, int y)
 }
 
 #ifdef GENERATION_DIAGNOSTICS
-static void display_grid(game_params *params, int *grid, int *numbers)
+static void display_grid(game_params *params, int *grid, int *numbers, int all)
 {
     unsigned char *egrid = snewn((params->w*2+3) * (params->h*2+3),
                                  unsigned char);
-    memset(egrid, 0, (params->w*2+3) * (params->h*2+3));
     int x, y;
     int r = (params->w*2+3);
 
+    memset(egrid, 0, (params->w*2+3) * (params->h*2+3));
+
     for (x = 0; x < params->w; x++)
         for (y = 0; y < params->h; y++) {
             int i = index(params, grid, x, y);
@@ -344,8 +363,8 @@ static void display_grid(game_params *params, int *grid, int *numbers)
     for (y = 1; y < 2*params->h+2; y++) {
         for (x = 1; x < 2*params->w+2; x++) {
             if (!((y|x)&1)) {
-                int k = index(params, numbers, x/2-1, y/2-1);
-                if (k) printf("%2d", k); else printf("  ");
+                int k = numbers ? index(params, numbers, x/2-1, y/2-1) : 0;
+                if (k || (all && numbers)) printf("%2d", k); else printf("  ");
             } else if (!((y&x)&1)) {
                 int v = egrid[y*r+x];
                 if ((y&1) && v) v = '-';
@@ -375,19 +394,27 @@ char *new_game_seed(game_params *params, random_state *rs)
 {
     int *grid, *numbers;
     struct rectlist *list;
-    int x, y, run, i;
+    int x, y, y2, y2last, yx, run, i;
     char *seed, *p;
+    game_params params2real, *params2 = &params2real;
 
-    grid = snewn(params->w * params->h, int);
-    numbers = snewn(params->w * params->h, int);
+    /*
+     * Set up the smaller width and height which we will use to
+     * generate the base grid.
+     */
+    params2->w = params->w / (1.0F + params->expandfactor);
+    if (params2->w < 2 && params->w >= 2) params2->w = 2;
+    params2->h = params->h / (1.0F + params->expandfactor);
+    if (params2->h < 2 && params->h >= 2) params2->h = 2;
 
-    for (y = 0; y < params->h; y++)
-        for (x = 0; x < params->w; x++) {
-            index(params, grid, x, y) = -1;
-            index(params, numbers, x, y) = 0;
+    grid = snewn(params2->w * params2->h, int);
+
+    for (y = 0; y < params2->h; y++)
+        for (x = 0; x < params2->w; x++) {
+            index(params2, grid, x, y) = -1;
         }
 
-    list = get_rectlist(params, grid);
+    list = get_rectlist(params2, grid);
     assert(list != NULL);
 
     /*
@@ -406,7 +433,7 @@ char *new_game_seed(game_params *params, random_state *rs)
         /*
          * Place it.
          */
-        place_rect(params, grid, r);
+        place_rect(params2, grid, r);
 
         /*
          * Winnow the list by removing any rectangles which
@@ -460,13 +487,13 @@ char *new_game_seed(game_params *params, random_state *rs)
      *     +--+-----+       in this fashion; so instead we can simply
      *                      replace the whole section with a single 3x3.
      */
-    for (x = 0; x < params->w; x++) {
-        for (y = 0; y < params->h; y++) {
-            if (index(params, grid, x, y) < 0) {
+    for (x = 0; x < params2->w; x++) {
+        for (y = 0; y < params2->h; y++) {
+            if (index(params2, grid, x, y) < 0) {
                 int dirs[4], ndirs;
 
 #ifdef GENERATION_DIAGNOSTICS
-                display_grid(params, grid, numbers);
+                display_grid(params2, grid, NULL, FALSE);
                 printf("singleton at %d,%d\n", x, y);
 #endif
 
@@ -486,23 +513,23 @@ char *new_game_seed(game_params *params, random_state *rs)
                  * create?
                  */
                 ndirs = 0;
-                if (x < params->w-1) {
-                    struct rect r = find_rect(params, grid, x+1, y);
+                if (x < params2->w-1) {
+                    struct rect r = find_rect(params2, grid, x+1, y);
                     if ((r.w * r.h > 2 && (r.y==y || r.y+r.h-1==y)) || r.h==1)
                         dirs[ndirs++] = 1;   /* right */
                 }
                 if (y > 0) {
-                    struct rect r = find_rect(params, grid, x, y-1);
+                    struct rect r = find_rect(params2, grid, x, y-1);
                     if ((r.w * r.h > 2 && (r.x==x || r.x+r.w-1==x)) || r.w==1)
                         dirs[ndirs++] = 2;   /* up */
                 }
                 if (x > 0) {
-                    struct rect r = find_rect(params, grid, x-1, y);
+                    struct rect r = find_rect(params2, grid, x-1, y);
                     if ((r.w * r.h > 2 && (r.y==y || r.y+r.h-1==y)) || r.h==1)
                         dirs[ndirs++] = 4;   /* left */
                 }
-                if (y < params->h-1) {
-                    struct rect r = find_rect(params, grid, x, y+1);
+                if (y < params2->h-1) {
+                    struct rect r = find_rect(params2, grid, x, y+1);
                     if ((r.w * r.h > 2 && (r.x==x || r.x+r.w-1==x)) || r.w==1)
                         dirs[ndirs++] = 8;   /* down */
                 }
@@ -516,11 +543,11 @@ char *new_game_seed(game_params *params, random_state *rs)
 
                     switch (dir) {
                       case 1:          /* right */
-                        assert(x < params->w+1);
+                        assert(x < params2->w+1);
 #ifdef GENERATION_DIAGNOSTICS
                         printf("extending right\n");
 #endif
-                        r1 = find_rect(params, grid, x+1, y);
+                        r1 = find_rect(params2, grid, x+1, y);
                         r2.x = x;
                         r2.y = y;
                         r2.w = 1 + r1.w;
@@ -534,7 +561,7 @@ char *new_game_seed(game_params *params, random_state *rs)
 #ifdef GENERATION_DIAGNOSTICS
                         printf("extending up\n");
 #endif
-                        r1 = find_rect(params, grid, x, y-1);
+                        r1 = find_rect(params2, grid, x, y-1);
                         r2.x = x;
                         r2.y = r1.y;
                         r2.w = 1;
@@ -548,7 +575,7 @@ char *new_game_seed(game_params *params, random_state *rs)
 #ifdef GENERATION_DIAGNOSTICS
                         printf("extending left\n");
 #endif
-                        r1 = find_rect(params, grid, x-1, y);
+                        r1 = find_rect(params2, grid, x-1, y);
                         r2.x = r1.x;
                         r2.y = y;
                         r2.w = 1 + r1.w;
@@ -558,11 +585,11 @@ char *new_game_seed(game_params *params, random_state *rs)
                         r1.h--;
                         break;
                       case 8:          /* down */
-                        assert(y < params->h+1);
+                        assert(y < params2->h+1);
 #ifdef GENERATION_DIAGNOSTICS
                         printf("extending down\n");
 #endif
-                        r1 = find_rect(params, grid, x, y+1);
+                        r1 = find_rect(params2, grid, x, y+1);
                         r2.x = x;
                         r2.y = y;
                         r2.w = 1;
@@ -573,8 +600,8 @@ char *new_game_seed(game_params *params, random_state *rs)
                         break;
                     }
                     if (r1.h > 0 && r1.w > 0)
-                        place_rect(params, grid, r1);
-                    place_rect(params, grid, r2);
+                        place_rect(params2, grid, r1);
+                    place_rect(params2, grid, r2);
                 } else {
 #ifndef NDEBUG
                     /*
@@ -585,12 +612,12 @@ char *new_game_seed(game_params *params, random_state *rs)
                      */
                     {
                         int xx, yy;
-                        assert(x > 0 && x < params->w-1);
-                        assert(y > 0 && y < params->h-1);
+                        assert(x > 0 && x < params2->w-1);
+                        assert(y > 0 && y < params2->h-1);
 
                         for (xx = x-1; xx <= x+1; xx++)
                             for (yy = y-1; yy <= y+1; yy++) {
-                                struct rect r = find_rect(params,grid,xx,yy);
+                                struct rect r = find_rect(params2,grid,xx,yy);
                                 assert(r.x >= x-1);
                                 assert(r.y >= y-1);
                                 assert(r.x+r.w-1 <= x+1);
@@ -620,7 +647,7 @@ char *new_game_seed(game_params *params, random_state *rs)
                         r.x = x-1;
                         r.y = y-1;
                         r.w = r.h = 3;
-                        place_rect(params, grid, r);
+                        place_rect(params2, grid, r);
                     }
                 }
             }
@@ -628,8 +655,192 @@ char *new_game_seed(game_params *params, random_state *rs)
     }
 
     /*
+     * We have now constructed a grid of the size specified in
+     * params2. Now we extend it into a grid of the size specified
+     * in params. We do this in two passes: we extend it vertically
+     * until it's the right height, then we transpose it, then
+     * extend it vertically again (getting it effectively the right
+     * width), then finally transpose again.
+     */
+    for (i = 0; i < 2; i++) {
+       int *grid2, *expand, *where;
+       game_params params3real, *params3 = &params3real;
+
+#ifdef GENERATION_DIAGNOSTICS
+       printf("before expansion:\n");
+       display_grid(params2, grid, NULL, TRUE);
+#endif
+
+       /*
+        * Set up the new grid.
+        */
+       grid2 = snewn(params2->w * params->h, int);
+       expand = snewn(params2->h-1, int);
+       where = snewn(params2->w, int);
+       params3->w = params2->w;
+       params3->h = params->h;
+
+       /*
+        * Decide which horizontal edges are going to get expanded,
+        * and by how much.
+        */
+       for (y = 0; y < params2->h-1; y++)
+           expand[y] = 0;
+       for (y = params2->h; y < params->h; y++) {
+           x = random_upto(rs, params2->h-1);
+           expand[x]++;
+       }
+
+#ifdef GENERATION_DIAGNOSTICS
+       printf("expand[] = {");
+       for (y = 0; y < params2->h-1; y++)
+           printf(" %d", expand[y]);
+       printf(" }\n");
+#endif
+
+       /*
+        * Perform the expansion. The way this works is that we
+        * alternately:
+        * 
+        *  - copy a row from grid into grid2
+        * 
+        *  - invent some number of additional rows in grid2 where
+        *    there was previously only a horizontal line between
+        *    rows in grid, and make random decisions about where
+        *    among these to place each rectangle edge that ran
+        *    along this line.
+        */
+       for (y = y2 = y2last = 0; y < params2->h; y++) {
+           /*
+            * Copy a single line from row y of grid into row y2 of
+            * grid2.
+            */
+           for (x = 0; x < params2->w; x++) {
+               int val = index(params2, grid, x, y);
+               if (val / params2->w == y &&   /* rect starts on this line */
+                   (y2 == 0 ||        /* we're at the very top, or... */
+                    index(params3, grid2, x, y2-1) / params3->w < y2last
+                                      /* this rect isn't already started */))
+                   index(params3, grid2, x, y2) =
+                   INDEX(params3, val % params2->w, y2);
+               else
+                   index(params3, grid2, x, y2) =
+                   index(params3, grid2, x, y2-1);
+           }
+
+           /*
+            * If that was the last line, terminate the loop early.
+            */
+           if (++y2 == params3->h)
+               break;
+
+           y2last = y2;
+
+           /*
+            * Invent some number of additional lines. First walk
+            * along this line working out where to put all the
+            * edges that coincide with it.
+            */
+           yx = -1;
+           for (x = 0; x < params2->w; x++) {
+               if (index(params2, grid, x, y) !=
+                   index(params2, grid, x, y+1)) {
+                   /*
+                    * This is a horizontal edge, so it needs
+                    * placing.
+                    */
+                   if (x == 0 ||
+                       (index(params2, grid, x-1, y) !=
+                        index(params2, grid, x, y) &&
+                        index(params2, grid, x-1, y+1) !=
+                        index(params2, grid, x, y+1))) {
+                       /*
+                        * Here we have the chance to make a new
+                        * decision.
+                        */
+                       yx = random_upto(rs, expand[y]+1);
+                   } else {
+                       /*
+                        * Here we just reuse the previous value of
+                        * yx.
+                        */
+                   }
+               } else
+                   yx = -1;
+               where[x] = yx;
+           }
+
+           for (yx = 0; yx < expand[y]; yx++) {
+               /*
+                * Invent a single row. For each square in the row,
+                * we copy the grid entry from the square above it,
+                * unless we're starting the new rectangle here.
+                */
+               for (x = 0; x < params2->w; x++) {
+                   if (yx == where[x]) {
+                       int val = index(params2, grid, x, y+1);
+                       val %= params2->w;
+                       val = INDEX(params3, val, y2);
+                       index(params3, grid2, x, y2) = val;
+                   } else
+                       index(params3, grid2, x, y2) = 
+                       index(params3, grid2, x, y2-1);
+               }
+
+               y2++;
+           }
+       }
+
+       sfree(expand);
+       sfree(where);
+
+#ifdef GENERATION_DIAGNOSTICS
+       printf("after expansion:\n");
+       display_grid(params3, grid2, NULL, TRUE);
+#endif
+       /*
+        * Transpose.
+        */
+       params2->w = params3->h;
+       params2->h = params3->w;
+       sfree(grid);
+       grid = snewn(params2->w * params2->h, int);
+       for (x = 0; x < params2->w; x++)
+           for (y = 0; y < params2->h; y++) {
+               int idx1 = INDEX(params2, x, y);
+               int idx2 = INDEX(params3, y, x);
+               int tmp;
+
+               tmp = grid2[idx2];
+               tmp = (tmp % params3->w) * params2->w + (tmp / params3->w);
+               grid[idx1] = tmp;
+           }
+
+       sfree(grid2);
+
+       {
+           int tmp;
+           tmp = params->w;
+           params->w = params->h;
+           params->h = tmp;
+       }
+
+#ifdef GENERATION_DIAGNOSTICS
+       printf("after transposition:\n");
+       display_grid(params2, grid, NULL, TRUE);
+#endif
+    }
+
+    /*
      * Place numbers.
      */
+    numbers = snewn(params->w * params->h, int);
+
+    for (y = 0; y < params->h; y++)
+        for (x = 0; x < params->w; x++) {
+            index(params, numbers, x, y) = 0;
+        }
+
     for (x = 0; x < params->w; x++) {
         for (y = 0; y < params->h; y++) {
             int idx = INDEX(params, x, y);
@@ -649,7 +860,7 @@ char *new_game_seed(game_params *params, random_state *rs)
     }
 
 #ifdef GENERATION_DIAGNOSTICS
-    display_grid(params, grid, numbers);
+    display_grid(params, grid, numbers, FALSE);
 #endif
 
     seed = snewn(11 * params->w * params->h, char);
@@ -697,7 +908,7 @@ char *validate_seed(game_params *params, char *seed)
         } else if (n == '_') {
             /* do nothing */;
         } else if (n > '0' && n <= '9') {
-            squares += atoi(seed-1);
+            squares++;
             while (*seed >= '0' && *seed <= '9')
                 seed++;
         } else
@@ -1145,7 +1356,7 @@ game_state *make_move(game_state *from, game_ui *ui, int x, int y, int button)
  * Drawing routines.
  */
 
-#define CORRECT 256
+#define CORRECT 65536
 
 #define COLOUR(k) ( (k)==1 ? COL_LINE : COL_DRAG )
 #define MAX(x,y) ( (x)>(y) ? (x) : (y) )
@@ -1154,7 +1365,7 @@ game_state *make_move(game_state *from, game_ui *ui, int x, int y, int button)
 struct game_drawstate {
     int started;
     int w, h;
-    unsigned short *visible;
+    unsigned int *visible;
 };
 
 void game_size(game_params *params, int *x, int *y)
@@ -1201,7 +1412,7 @@ game_drawstate *game_new_drawstate(game_state *state)
     ds->started = FALSE;
     ds->w = state->w;
     ds->h = state->h;
-    ds->visible = snewn(ds->w * ds->h, unsigned short);
+    ds->visible = snewn(ds->w * ds->h, unsigned int);
     for (i = 0; i < ds->w * ds->h; i++)
         ds->visible[i] = 0xFFFF;
 
@@ -1215,7 +1426,8 @@ void game_free_drawstate(game_drawstate *ds)
 }
 
 void draw_tile(frontend *fe, game_state *state, int x, int y,
-               unsigned char *hedge, unsigned char *vedge, int correct)
+               unsigned char *hedge, unsigned char *vedge,
+              unsigned char *corners, int correct)
 {
     int cx = COORD(x), cy = COORD(y);
     char str[80];
@@ -1253,45 +1465,29 @@ void draw_tile(frontend *fe, game_state *state, int x, int y,
     /*
      * Draw corners.
      */
-    if ((HRANGE(state,x-1,y) && index(state,hedge,x-1,y)) ||
-       (VRANGE(state,x,y-1) && index(state,vedge,x,y-1)))
+    if (index(state,corners,x,y))
        draw_rect(fe, cx, cy, 2, 2,
-                  COLOUR(MAX4(index(state,hedge,x-1,y),
-                              index(state,vedge,x,y-1),
-                              index(state,hedge,x,y),
-                              index(state,vedge,x,y))));
-    if ((HRANGE(state,x+1,y) && index(state,hedge,x+1,y)) ||
-       (VRANGE(state,x+1,y-1) && index(state,vedge,x+1,y-1)))
+                  COLOUR(index(state,corners,x,y)));
+    if (x+1 < state->w && index(state,corners,x+1,y))
        draw_rect(fe, cx+TILE_SIZE-1, cy, 2, 2,
-                  COLOUR(MAX4(index(state,hedge,x+1,y),
-                              index(state,vedge,x+1,y-1),
-                              index(state,hedge,x,y),
-                              index(state,vedge,x+1,y))));
-    if ((HRANGE(state,x-1,y+1) && index(state,hedge,x-1,y+1)) ||
-       (VRANGE(state,x,y+1) && index(state,vedge,x,y+1)))
+                  COLOUR(index(state,corners,x+1,y)));
+    if (y+1 < state->h && index(state,corners,x,y+1))
        draw_rect(fe, cx, cy+TILE_SIZE-1, 2, 2,
-                  COLOUR(MAX4(index(state,hedge,x-1,y+1),
-                              index(state,vedge,x,y+1),
-                              index(state,hedge,x,y+1),
-                              index(state,vedge,x,y))));
-    if ((HRANGE(state,x+1,y+1) && index(state,hedge,x+1,y+1)) ||
-       (VRANGE(state,x+1,y+1) && index(state,vedge,x+1,y+1)))
+                  COLOUR(index(state,corners,x,y+1)));
+    if (x+1 < state->w && y+1 < state->h && index(state,corners,x+1,y+1))
        draw_rect(fe, cx+TILE_SIZE-1, cy+TILE_SIZE-1, 2, 2,
-                  COLOUR(MAX4(index(state,hedge,x+1,y+1),
-                              index(state,vedge,x+1,y+1),
-                              index(state,hedge,x,y+1),
-                              index(state,vedge,x+1,y))));
+                  COLOUR(index(state,corners,x+1,y+1)));
 
     draw_update(fe, cx, cy, TILE_SIZE+1, TILE_SIZE+1);
 }
 
 void game_redraw(frontend *fe, game_drawstate *ds, game_state *oldstate,
-                 game_state *state, game_ui *ui,
+                 game_state *state, int dir, game_ui *ui,
                  float animtime, float flashtime)
 {
     int x, y;
     unsigned char *correct;
-    unsigned char *hedge, *vedge;
+    unsigned char *hedge, *vedge, *corners;
 
     correct = get_correct(state);
 
@@ -1306,6 +1502,28 @@ void game_redraw(frontend *fe, game_drawstate *ds, game_state *oldstate,
         vedge = state->vedge;
     }
 
+    corners = snewn(state->w * state->h, unsigned char);
+    memset(corners, 0, state->w * state->h);
+    for (x = 0; x < state->w; x++)
+       for (y = 0; y < state->h; y++) {
+           if (x > 0) {
+               int e = index(state, vedge, x, y);
+               if (index(state,corners,x,y) < e)
+                   index(state,corners,x,y) = e;
+               if (y+1 < state->h &&
+                   index(state,corners,x,y+1) < e)
+                   index(state,corners,x,y+1) = e;
+           }
+           if (y > 0) {
+               int e = index(state, hedge, x, y);
+               if (index(state,corners,x,y) < e)
+                   index(state,corners,x,y) = e;
+               if (x+1 < state->w &&
+                   index(state,corners,x+1,y) < e)
+                   index(state,corners,x+1,y) = e;
+           }
+       }
+
     if (!ds->started) {
        draw_rect(fe, 0, 0,
                  state->w * TILE_SIZE + 2*BORDER + 1,
@@ -1320,22 +1538,29 @@ void game_redraw(frontend *fe, game_drawstate *ds, game_state *oldstate,
 
     for (x = 0; x < state->w; x++)
        for (y = 0; y < state->h; y++) {
-           unsigned short c = 0;
+           unsigned int c = 0;
 
            if (HRANGE(state,x,y))
                 c |= index(state,hedge,x,y);
-           if (HRANGE(state,x+1,y))
-               c |= index(state,hedge,x+1,y) << 2;
+           if (HRANGE(state,x,y+1))
+               c |= index(state,hedge,x,y+1) << 2;
            if (VRANGE(state,x,y))
                c |= index(state,vedge,x,y) << 4;
-           if (VRANGE(state,x,y+1))
-               c |= index(state,vedge,x,y+1) << 6;
+           if (VRANGE(state,x+1,y))
+               c |= index(state,vedge,x+1,y) << 6;
+           c |= index(state,corners,x,y) << 8;
+           if (x+1 < state->w)
+               c |= index(state,corners,x+1,y) << 10;
+           if (y+1 < state->h)
+               c |= index(state,corners,x,y+1) << 12;
+           if (x+1 < state->w && y+1 < state->h)
+               c |= index(state,corners,x+1,y+1) << 14;
            if (index(state, correct, x, y) && !flashtime)
                c |= CORRECT;
 
            if (index(ds,ds->visible,x,y) != c) {
-               draw_tile(fe, state, x, y, hedge, vedge, c & CORRECT);
-               /* index(ds,ds->visible,x,y) = c; */
+               draw_tile(fe, state, x, y, hedge, vedge, corners, c & CORRECT);
+               index(ds,ds->visible,x,y) = c;
            }
        }
 
@@ -1344,15 +1569,16 @@ void game_redraw(frontend *fe, game_drawstate *ds, game_state *oldstate,
         sfree(vedge);
    }
 
+    sfree(corners);
     sfree(correct);
 }
 
-float game_anim_length(game_state *oldstate, game_state *newstate)
+float game_anim_length(game_state *oldstate, game_state *newstate, int dir)
 {
     return 0.0F;
 }
 
-float game_flash_length(game_state *oldstate, game_state *newstate)
+float game_flash_length(game_state *oldstate, game_state *newstate, int dir)
 {
     if (!oldstate->completed && newstate->completed)
         return FLASH_TIME;