chiark / gitweb /
Apply some optimisation to Undead's get_unique() function, which was
[sgt-puzzles.git] / undead.c
index 6ce6eaa272bbd3f6fa90904e3295a451a6b5487f..e38c96844d33107cde490b0d2eba1a5d2f046e82 100644 (file)
--- a/undead.c
+++ b/undead.c
@@ -52,9 +52,9 @@ enum {
     NCOLOURS
 };
 
-#define DIFFLIST(A) \
-    A(EASY,Easy,e) \
-    A(NORMAL,Normal,n) \
+#define DIFFLIST(A)                             \
+    A(EASY,Easy,e)                              \
+    A(NORMAL,Normal,n)                          \
     A(TRICKY,Tricky,t)
 #define ENUM(upper,title,lower) DIFF_ ## upper,
 #define TITLE(upper,title,lower) #title,
@@ -576,8 +576,9 @@ int next_list(struct guess *g, int pos) {
 
 void get_unique(game_state *state, int counter, random_state *rs) {
 
-    int p,i,c,count_uniques;
+    int p,i,c,pathlimit,count_uniques;
     struct guess path_guess;
+    int *view_count;
     
     struct entry {
         struct entry *link;
@@ -589,10 +590,10 @@ void get_unique(game_state *state, int counter, random_state *rs) {
     struct {
         struct entry *head;
         struct entry *node;
-    } views, single_views, loop_views, test_views;
+    } views, single_views, test_views;
 
     struct entry test_entry;
-    
+
     path_guess.length = state->common->paths[counter].num_monsters;
     path_guess.guess = snewn(path_guess.length,int);
     path_guess.possible = snewn(path_guess.length,int);
@@ -603,32 +604,29 @@ void get_unique(game_state *state, int counter, random_state *rs) {
         path_guess.possible[p] =
             state->guess[state->common->paths[counter].mapping[p]];
         switch (path_guess.possible[p]) {
-            case 1: path_guess.guess[p] = 1; break;
-            case 2: path_guess.guess[p] = 2; break;
-            case 3: path_guess.guess[p] = 1; break;
-            case 4: path_guess.guess[p] = 4; break;
-            case 5: path_guess.guess[p] = 1; break;
-            case 6: path_guess.guess[p] = 2; break;
-            case 7: path_guess.guess[p] = 1; break;
+          case 1: path_guess.guess[p] = 1; break;
+          case 2: path_guess.guess[p] = 2; break;
+          case 3: path_guess.guess[p] = 1; break;
+          case 4: path_guess.guess[p] = 4; break;
+          case 5: path_guess.guess[p] = 1; break;
+          case 6: path_guess.guess[p] = 2; break;
+          case 7: path_guess.guess[p] = 1; break;
         }
     }
 
     views.head = NULL;
     views.node = NULL;
+
+    pathlimit = state->common->paths[counter].length + 1;
+    view_count = snewn(pathlimit*pathlimit, int);
+    for (i = 0; i < pathlimit*pathlimit; i++)
+        view_count[i] = 0;
     
     do {
-        int mirror;
+        int mirror, start_view, end_view;
         
-        views.node = snewn(1,struct entry);
-        views.node->link = views.head;
-        views.node->guess = snewn(path_guess.length,int);
-        views.head = views.node;
-        views.node->start_view = 0;
-        views.node->end_view = 0;
-        memcpy(views.node->guess, path_guess.guess,
-               path_guess.length*sizeof(int));
-
         mirror = FALSE;
+        start_view = 0;
         for (p=0;p<state->common->paths[counter].length;p++) {
             if (state->common->paths[counter].p[p] == -1) mirror = TRUE;
             else {
@@ -636,17 +634,18 @@ void get_unique(game_state *state, int counter, random_state *rs) {
                     if (state->common->paths[counter].p[p] ==
                         state->common->paths[counter].mapping[i]) {
                         if (path_guess.guess[i] == 1 && mirror == TRUE)
-                            views.node->start_view++;
+                            start_view++;
                         if (path_guess.guess[i] == 2 && mirror == FALSE)
-                            views.node->start_view++;
+                            start_view++;
                         if (path_guess.guess[i] == 4)
-                            views.node->start_view++;
+                            start_view++;
                         break;
                     }
                 }
             }
         }
         mirror = FALSE;
+        end_view = 0;
         for (p=state->common->paths[counter].length-1;p>=0;p--) {
             if (state->common->paths[counter].p[p] == -1) mirror = TRUE;
             else {
@@ -654,16 +653,31 @@ void get_unique(game_state *state, int counter, random_state *rs) {
                     if (state->common->paths[counter].p[p] ==
                         state->common->paths[counter].mapping[i]) {
                         if (path_guess.guess[i] == 1 && mirror == TRUE)
-                            views.node->end_view++;
+                            end_view++;
                         if (path_guess.guess[i] == 2 && mirror == FALSE)
-                            views.node->end_view++;
+                            end_view++;
                         if (path_guess.guess[i] == 4)
-                            views.node->end_view++;
+                            end_view++;
                         break;
                     }
                 }
             }
         }
+
+        assert(start_view >= 0 && start_view < pathlimit);
+        assert(end_view >= 0 && end_view < pathlimit);
+        i = start_view * pathlimit + end_view;
+        view_count[i]++;
+        if (view_count[i] == 1) {
+            views.node = snewn(1,struct entry);
+            views.node->link = views.head;
+            views.node->guess = snewn(path_guess.length,int);
+            views.head = views.node;
+            views.node->start_view = start_view;
+            views.node->end_view = end_view;
+            memcpy(views.node->guess, path_guess.guess,
+                   path_guess.length*sizeof(int));
+        }
     } while (next_list(&path_guess, path_guess.length-1));
 
     /*  extract single entries from view list */
@@ -680,17 +694,8 @@ void get_unique(game_state *state, int counter, random_state *rs) {
     while (test_views.head != NULL) {
         test_views.node = test_views.head;
         test_views.head = test_views.head->link;
-        c = 0;
-        loop_views.head = views.head;
-        loop_views.node = views.node;
-        while (loop_views.head != NULL) {
-            loop_views.node = loop_views.head;
-            loop_views.head = loop_views.head->link;
-            if (test_views.node->start_view == loop_views.node->start_view &&
-                test_views.node->end_view == loop_views.node->end_view)
-                c++;
-        }
-        if (c == 1) {
+        i = test_views.node->start_view * pathlimit + test_views.node->end_view;
+        if (view_count[i] == 1) {
             single_views.node = snewn(1,struct entry);
             single_views.node->link = single_views.head;
             single_views.node->guess = snewn(path_guess.length,int);
@@ -703,6 +708,8 @@ void get_unique(game_state *state, int counter, random_state *rs) {
         }
     }
 
+    sfree(view_count);
+
     if (count_uniques > 0) {
         test_entry.start_view = 0;
         test_entry.end_view = 0;
@@ -841,13 +848,13 @@ int solve_iterative(game_state *state, struct path *paths) {
 
             for (i=0;i<paths[p].num_monsters;i++) {
                 switch (state->guess[paths[p].mapping[i]]) {
-                    case 1: loop.guess[i] = 1; break;
-                    case 2: loop.guess[i] = 2; break;
-                    case 3: loop.guess[i] = 1; break;
-                    case 4: loop.guess[i] = 4; break;
-                    case 5: loop.guess[i] = 1; break;
-                    case 6: loop.guess[i] = 2; break;
-                    case 7: loop.guess[i] = 1; break;
+                  case 1: loop.guess[i] = 1; break;
+                  case 2: loop.guess[i] = 2; break;
+                  case 3: loop.guess[i] = 1; break;
+                  case 4: loop.guess[i] = 4; break;
+                  case 5: loop.guess[i] = 1; break;
+                  case 6: loop.guess[i] = 2; break;
+                  case 7: loop.guess[i] = 1; break;
                 }
                 loop.possible[i] = state->guess[paths[p].mapping[i]];
                 possible[paths[p].mapping[i]] = 0;
@@ -900,13 +907,13 @@ int solve_bruteforce(game_state *state, struct path *paths) {
     for (i=0;i<state->common->num_total;i++) {
         loop.possible[i] = state->guess[i];
         switch (state->guess[i]) {
-            case 1: loop.guess[i] = 1; break;
-            case 2: loop.guess[i] = 2; break;
-            case 3: loop.guess[i] = 1; break;
-            case 4: loop.guess[i] = 4; break;
-            case 5: loop.guess[i] = 1; break;
-            case 6: loop.guess[i] = 2; break;
-            case 7: loop.guess[i] = 1; break;
+          case 1: loop.guess[i] = 1; break;
+          case 2: loop.guess[i] = 2; break;
+          case 3: loop.guess[i] = 1; break;
+          case 4: loop.guess[i] = 4; break;
+          case 5: loop.guess[i] = 1; break;
+          case 6: loop.guess[i] = 2; break;
+          case 7: loop.guess[i] = 1; break;
         }
     }
 
@@ -981,23 +988,23 @@ static char *new_game_desc(game_params *params, random_state *rs,
          * empty monster cells */
         count = 0;
         for (h=1;h<new->common->params.h+1;h++)
-        for (w=1;w<new->common->params.w+1;w++) {
-            c = random_upto(rs,5);
-            if (c >= 2) {
-                new->common->grid[w+h*(new->common->params.w+2)] = CELL_EMPTY;
-                new->common->xinfo[w+h*(new->common->params.w+2)] = count++;
-            }
-            else if (c == 0) {
-                new->common->grid[w+h*(new->common->params.w+2)] = 
-                    CELL_MIRROR_L;
-                new->common->xinfo[w+h*(new->common->params.w+2)] = -1;
-            }
-            else {
-                new->common->grid[w+h*(new->common->params.w+2)] =
-                    CELL_MIRROR_R;
-                new->common->xinfo[w+h*(new->common->params.w+2)] = -1;         
+            for (w=1;w<new->common->params.w+1;w++) {
+                c = random_upto(rs,5);
+                if (c >= 2) {
+                    new->common->grid[w+h*(new->common->params.w+2)] = CELL_EMPTY;
+                    new->common->xinfo[w+h*(new->common->params.w+2)] = count++;
+                }
+                else if (c == 0) {
+                    new->common->grid[w+h*(new->common->params.w+2)] = 
+                        CELL_MIRROR_L;
+                    new->common->xinfo[w+h*(new->common->params.w+2)] = -1;
+                }
+                else {
+                    new->common->grid[w+h*(new->common->params.w+2)] =
+                        CELL_MIRROR_R;
+                    new->common->xinfo[w+h*(new->common->params.w+2)] = -1;         
+                }
             }
-        }
         new->common->num_total = count; /* Total number of monsters in maze */
 
         /* Puzzle is boring if it has too few monster cells. Discard
@@ -1050,10 +1057,10 @@ static char *new_game_desc(game_params *params, random_state *rs,
         /* Grid is invalid if max. path length > threshold. Discard
          * grid, make new one */
         switch (new->common->params.diff) {
-            case DIFF_EASY:     max_length = min(new->common->params.w,new->common->params.h) + 1; break;
-            case DIFF_NORMAL:   max_length = (max(new->common->params.w,new->common->params.h) * 3) / 2; break;
-            case DIFF_TRICKY:   max_length = 9; break;
-            default:            max_length = 9; break;
+          case DIFF_EASY:     max_length = min(new->common->params.w,new->common->params.h) + 1; break;
+          case DIFF_NORMAL:   max_length = (max(new->common->params.w,new->common->params.h) * 3) / 2; break;
+          case DIFF_TRICKY:   max_length = 9; break;
+          default:            max_length = 9; break;
         }
 
         for (p=0;p<new->common->num_paths;p++) {
@@ -1077,10 +1084,10 @@ static char *new_game_desc(game_params *params, random_state *rs,
             even less paths with unique solutions */
 
         switch (new->common->params.diff) {
-            case DIFF_EASY:   filling = 2; break;
-            case DIFF_NORMAL: filling = min( (new->common->params.w+new->common->params.h) , (new->common->num_total)/2 ); break;
-            case DIFF_TRICKY: filling = max( (new->common->params.w+new->common->params.h) , (new->common->num_total)/2 ); break;
-            default:          filling = 0; break;
+          case DIFF_EASY:   filling = 2; break;
+          case DIFF_NORMAL: filling = min( (new->common->params.w+new->common->params.h) , (new->common->num_total)/2 ); break;
+          case DIFF_TRICKY: filling = max( (new->common->params.w+new->common->params.h) , (new->common->num_total)/2 ); break;
+          default:          filling = 0; break;
         }
 
         count = 0;
@@ -1125,14 +1132,14 @@ static char *new_game_desc(game_params *params, random_state *rs,
         }
 
         for (w=1;w<new->common->params.w+1;w++)
-        for (h=1;h<new->common->params.h+1;h++) {
-            c = new->common->xinfo[w+h*(new->common->params.w+2)];
-            if (c >= 0) {
-                if (new->guess[c] == 1) new->common->grid[w+h*(new->common->params.w+2)] = CELL_GHOST;
-                if (new->guess[c] == 2) new->common->grid[w+h*(new->common->params.w+2)] = CELL_VAMPIRE;
-                if (new->guess[c] == 4) new->common->grid[w+h*(new->common->params.w+2)] = CELL_ZOMBIE;                 
+            for (h=1;h<new->common->params.h+1;h++) {
+                c = new->common->xinfo[w+h*(new->common->params.w+2)];
+                if (c >= 0) {
+                    if (new->guess[c] == 1) new->common->grid[w+h*(new->common->params.w+2)] = CELL_GHOST;
+                    if (new->guess[c] == 2) new->common->grid[w+h*(new->common->params.w+2)] = CELL_VAMPIRE;
+                    if (new->guess[c] == 4) new->common->grid[w+h*(new->common->params.w+2)] = CELL_ZOMBIE;                 
+                }
             }
-        }
 
         /* Prepare path information needed by the solver (containing all hints) */  
         for (p=0;p<new->common->num_paths;p++) {
@@ -1249,26 +1256,26 @@ static char *new_game_desc(game_params *params, random_state *rs,
     /* Encode grid */
     count = 0;
     for (y=1;y<new->common->params.h+1;y++)
-    for (x=1;x<new->common->params.w+1;x++) {
-        c = new->common->grid[x+y*(new->common->params.w+2)];
-        if (count > 25) {
-            *e++ = 'z';
-            count -= 26;
-        }
-        if (c != CELL_MIRROR_L && c != CELL_MIRROR_R) {
-            count++;
-        }
-        else if (c == CELL_MIRROR_L) {
-            if (count > 0) *e++ = (count-1 + 'a');
-            *e++ = 'L';
-            count = 0;
-        }
-        else {
-            if (count > 0) *e++ = (count-1 + 'a');
-            *e++ = 'R';
-            count = 0;          
+        for (x=1;x<new->common->params.w+1;x++) {
+            c = new->common->grid[x+y*(new->common->params.w+2)];
+            if (count > 25) {
+                *e++ = 'z';
+                count -= 26;
+            }
+            if (c != CELL_MIRROR_L && c != CELL_MIRROR_R) {
+                count++;
+            }
+            else if (c == CELL_MIRROR_L) {
+                if (count > 0) *e++ = (count-1 + 'a');
+                *e++ = 'L';
+                count = 0;
+            }
+            else {
+                if (count > 0) *e++ = (count-1 + 'a');
+                *e++ = 'R';
+                count = 0;          
+            }
         }
-    }
     if (count > 0) *e++ = (count-1 + 'a');
 
     /* Encode hints */
@@ -1644,10 +1651,11 @@ struct game_drawstate {
 };
 
 #define TILESIZE (ds->tilesize)
-#define BORDER (TILESIZE/2)
+#define BORDER (TILESIZE/4)
 
-static char *interpret_move(game_state *state, game_ui *ui, game_drawstate *ds,
-                            int x, int y, int button) {
+static char *interpret_move(game_state *state, game_ui *ui,
+                            const game_drawstate *ds, int x, int y, int button)
+{
     int gx,gy;
     int g,xi;
     char buf[80]; 
@@ -1656,7 +1664,7 @@ static char *interpret_move(game_state *state, game_ui *ui, game_drawstate *ds,
     gy = ((y-BORDER-2) / TILESIZE ) - 1;
 
     if (button == 'a' || button == 'A') {
-        ds->ascii = ui->ascii ? FALSE : TRUE;
+        ui->ascii = !ui->ascii;
         return "";      
     }
     
@@ -1693,11 +1701,11 @@ static char *interpret_move(game_state *state, game_ui *ui, game_drawstate *ds,
             ui->hy = 1;
         }
         else switch (button) {
-            case CURSOR_UP:     ui->hy -= (ui->hy > 1)     ? 1 : 0; break;
-            case CURSOR_DOWN:   ui->hy += (ui->hy < ds->h) ? 1 : 0; break;
-            case CURSOR_RIGHT:  ui->hx += (ui->hx < ds->w) ? 1 : 0; break;
-            case CURSOR_LEFT:   ui->hx -= (ui->hx > 1)     ? 1 : 0; break;
-        }
+              case CURSOR_UP:     ui->hy -= (ui->hy > 1)     ? 1 : 0; break;
+              case CURSOR_DOWN:   ui->hy += (ui->hy < ds->h) ? 1 : 0; break;
+              case CURSOR_RIGHT:  ui->hx += (ui->hx < ds->w) ? 1 : 0; break;
+              case CURSOR_LEFT:   ui->hx -= (ui->hx > 1)     ? 1 : 0; break;
+            }
         ui->hshow = ui->hcursor = 1;
         return "";
     }
@@ -1712,24 +1720,23 @@ static char *interpret_move(game_state *state, game_ui *ui, game_drawstate *ds,
         if (xi >= 0 && !state->common->fixed[xi]) {
             if (button == 'g' || button == 'G' || button == '1') {
                 sprintf(buf,"g%d",xi);
-                                ui->hpencil = ui->hshow = 0;
+                if (!ui->hcursor) ui->hpencil = ui->hshow = 0;
                 return dupstr(buf);
             }
             if (button == 'v' || button == 'V' || button == '2') {
                 sprintf(buf,"v%d",xi);
-                                ui->hpencil = ui->hshow = 0;
+                if (!ui->hcursor) ui->hpencil = ui->hshow = 0;
                 return dupstr(buf);
             }
             if (button == 'z' || button == 'Z' || button == '3') {
                 sprintf(buf,"z%d",xi);
-                                ui->hpencil = ui->hshow = 0;
+                if (!ui->hcursor) ui->hpencil = ui->hshow = 0;
                 return dupstr(buf);
             }
             if (button == 'e' || button == 'E' || button == CURSOR_SELECT2 ||
                 button == '0' || button == '\b') {
-                if (!ui->hcursor) ui->hshow = 0;
                 sprintf(buf,"E%d",xi);
-                                ui->hpencil = ui->hshow = 0;
+                if (!ui->hcursor) ui->hpencil = ui->hshow = 0;
                 return dupstr(buf);
             }
         }       
@@ -1818,36 +1825,36 @@ int check_numbers_draw(game_state *state, int *guess) {
         valid = FALSE; 
         state->count_errors[0] = TRUE; 
         for (x=1;x<state->common->params.w+1;x++)
-        for (y=1;y<state->common->params.h+1;y++) {
-            xy = x+y*(state->common->params.w+2);
-            if (state->common->xinfo[xy] >= 0 &&
-                guess[state->common->xinfo[xy]] == 1)
-                state->cell_errors[xy] = TRUE;
-        }
+            for (y=1;y<state->common->params.h+1;y++) {
+                xy = x+y*(state->common->params.w+2);
+                if (state->common->xinfo[xy] >= 0 &&
+                    guess[state->common->xinfo[xy]] == 1)
+                    state->cell_errors[xy] = TRUE;
+            }
     }
     if (count_vampires > state->common->num_vampires ||
         (filled && count_vampires != state->common->num_vampires) ) {
         valid = FALSE; 
         state->count_errors[1] = TRUE; 
         for (x=1;x<state->common->params.w+1;x++)
-        for (y=1;y<state->common->params.h+1;y++) {
-            xy = x+y*(state->common->params.w+2);
-            if (state->common->xinfo[xy] >= 0 &&
-                guess[state->common->xinfo[xy]] == 2)
-                state->cell_errors[xy] = TRUE;
-        }
+            for (y=1;y<state->common->params.h+1;y++) {
+                xy = x+y*(state->common->params.w+2);
+                if (state->common->xinfo[xy] >= 0 &&
+                    guess[state->common->xinfo[xy]] == 2)
+                    state->cell_errors[xy] = TRUE;
+            }
     }
     if (count_zombies > state->common->num_zombies ||
         (filled && count_zombies != state->common->num_zombies) )  {
         valid = FALSE; 
         state->count_errors[2] = TRUE; 
         for (x=1;x<state->common->params.w+1;x++)
-        for (y=1;y<state->common->params.h+1;y++) {
-            xy = x+y*(state->common->params.w+2);
-            if (state->common->xinfo[xy] >= 0 &&
-                guess[state->common->xinfo[xy]] == 4)
-                state->cell_errors[xy] = TRUE;
-        }
+            for (y=1;y<state->common->params.h+1;y++) {
+                xy = x+y*(state->common->params.w+2);
+                if (state->common->xinfo[xy] >= 0 &&
+                    guess[state->common->xinfo[xy]] == 4)
+                    state->cell_errors[xy] = TRUE;
+            }
     }
 
     return valid;
@@ -1974,8 +1981,12 @@ static game_state *execute_move(game_state *state, char *move) {
 
 static void game_compute_size(game_params *params, int tilesize,
                               int *x, int *y) {
-    *x = tilesize + (2 + params->w) * tilesize;
-    *y = tilesize + (3 + params->h) * tilesize;
+    /* Ick: fake up `ds->tilesize' for macro expansion purposes */
+    struct { int tilesize; } ads, *ds = &ads;
+    ads.tilesize = tilesize;
+
+    *x = 2*BORDER+(params->w+2)*TILESIZE;
+    *y = 2*BORDER+(params->h+3)*TILESIZE;
     return;
 }
 
@@ -2245,20 +2256,20 @@ static void draw_monster_count(drawing *dr, game_drawstate *ds,
     dh = TILESIZE;
     dx = BORDER+(ds->w+2)*TILESIZE/2+TILESIZE/4;
     switch (c) {
-        case 0: 
-            sprintf(buf,"%d",state->common->num_ghosts);
-            sprintf(bufm,"G");
-            dx -= 3*TILESIZE/2;
-            break;
-        case 1: 
-            sprintf(buf,"%d",state->common->num_vampires); 
-            sprintf(bufm,"V");
-            break;
-        case 2: 
-            sprintf(buf,"%d",state->common->num_zombies); 
-            sprintf(bufm,"Z");
-            dx += 3*TILESIZE/2;
-            break;
+      case 0: 
+        sprintf(buf,"%d",state->common->num_ghosts);
+        sprintf(bufm,"G");
+        dx -= 3*TILESIZE/2;
+        break;
+      case 1: 
+        sprintf(buf,"%d",state->common->num_vampires); 
+        sprintf(bufm,"V");
+        break;
+      case 2: 
+        sprintf(buf,"%d",state->common->num_zombies); 
+        sprintf(bufm,"Z");
+        dx += 3*TILESIZE/2;
+        break;
     }
 
     if (!ds->ascii) { 
@@ -2352,37 +2363,37 @@ static void draw_big_monster(drawing *dr, game_drawstate *ds, game_state *state,
 static void draw_pencils(drawing *dr, game_drawstate *ds, game_state *state,
                          int x, int y, int pencil) {
     int dx, dy;
-        int monsters[4];
-        int i, j, px, py;
+    int monsters[4];
+    int i, j, px, py;
     char buf[10];
     dx = BORDER+(x* ds->tilesize)+(TILESIZE/4);
     dy = BORDER+(y* ds->tilesize)+(TILESIZE/4)+TILESIZE;
 
-        for (i = 0, j = 1; j < 8; j *= 2)
-            if (pencil & j)
-                monsters[i++] = j;
-        while (i < 4)
-            monsters[i++] = 0;
-
-        for (py = 0; py < 2; py++)
-            for (px = 0; px < 2; px++)
-                if (monsters[py*2+px]) {
-                    if (!ds->ascii) {
-                        draw_monster(dr, ds,
-                                     dx + TILESIZE/2 * px, dy + TILESIZE/2 * py,
-                                     TILESIZE/2, 0, monsters[py*2+px]);
-                    }
-                    else {
-                        switch (monsters[py*2+px]) {
-                            case 1: sprintf(buf,"G"); break;
-                            case 2: sprintf(buf,"V"); break;
-                            case 4: sprintf(buf,"Z"); break;
-                        }
-                        draw_text(dr,dx + TILESIZE/2 * px,dy + TILESIZE/2 * py,
-                                  FONT_FIXED,TILESIZE/4,ALIGN_HCENTRE|ALIGN_VCENTRE,
-                                  COL_TEXT,buf);
+    for (i = 0, j = 1; j < 8; j *= 2)
+        if (pencil & j)
+            monsters[i++] = j;
+    while (i < 4)
+        monsters[i++] = 0;
+
+    for (py = 0; py < 2; py++)
+        for (px = 0; px < 2; px++)
+            if (monsters[py*2+px]) {
+                if (!ds->ascii) {
+                    draw_monster(dr, ds,
+                                 dx + TILESIZE/2 * px, dy + TILESIZE/2 * py,
+                                 TILESIZE/2, 0, monsters[py*2+px]);
+                }
+                else {
+                    switch (monsters[py*2+px]) {
+                      case 1: sprintf(buf,"G"); break;
+                      case 2: sprintf(buf,"V"); break;
+                      case 4: sprintf(buf,"Z"); break;
                     }
+                    draw_text(dr,dx + TILESIZE/2 * px,dy + TILESIZE/2 * py,
+                              FONT_FIXED,TILESIZE/4,ALIGN_HCENTRE|ALIGN_VCENTRE,
+                              COL_TEXT,buf);
                 }
+            }
     draw_update(dr,dx-(TILESIZE/4)+2,dy-(TILESIZE/4)+2,
                 (TILESIZE/2)-3,(TILESIZE/2)-3);
 
@@ -2392,10 +2403,10 @@ static void draw_pencils(drawing *dr, game_drawstate *ds, game_state *state,
 #define FLASH_TIME 0.7F
 
 static void game_redraw(drawing *dr, game_drawstate *ds, game_state *oldstate,
-            game_state *state, int dir, game_ui *ui,
-            float animtime, float flashtime) {
+                        game_state *state, int dir, game_ui *ui,
+                        float animtime, float flashtime) {
     int i,j,x,y,xy;
-    int stale, xi, c, hflash, hchanged;
+    int stale, xi, c, hflash, hchanged, changed_ascii;
 
     hflash = (int)(flashtime * 5 / FLASH_TIME) % 2;
 
@@ -2410,8 +2421,8 @@ static void game_redraw(drawing *dr, game_drawstate *ds, game_state *oldstate,
                 draw_rect(dr, BORDER+(ds->tilesize*(i+1))+1,
                           BORDER+(ds->tilesize*(j+2))+1, ds->tilesize-1,
                           ds->tilesize-1, COL_BACKGROUND);
-        draw_update(dr,BORDER+TILESIZE-1,BORDER+2*TILESIZE-1,
-                    (ds->w)*TILESIZE+3, (ds->h)*TILESIZE+3);
+        draw_update(dr, 0, 0, 2*BORDER+(ds->w+2)*TILESIZE,
+                    2*BORDER+(ds->h+3)*TILESIZE);
     }
 
     hchanged = FALSE;
@@ -2419,13 +2430,19 @@ static void game_redraw(drawing *dr, game_drawstate *ds, game_state *oldstate,
         ds->hshow != ui->hshow || ds->hpencil != ui->hpencil)
         hchanged = TRUE;
 
+    if (ds->ascii != ui->ascii) {
+        ds->ascii = ui->ascii;
+        changed_ascii = TRUE;
+    } else
+        changed_ascii = FALSE;
+
     /* Draw monster count hints */
 
     for (i=0;i<3;i++) {
         stale = FALSE;
         if (!ds->started) stale = TRUE;
         if (ds->hflash != hflash) stale = TRUE;
-        if (ds->ascii != ui->ascii) stale = TRUE;
+        if (changed_ascii) stale = TRUE;
         if (ds->count_errors[i] != state->count_errors[i]) {
             stale = TRUE;
             ds->count_errors[i] = state->count_errors[i];
@@ -2473,54 +2490,53 @@ static void game_redraw(drawing *dr, game_drawstate *ds, game_state *oldstate,
 
     /* Draw puzzle grid contents */
     for (x = 1; x < ds->w+1; x++)
-    for (y = 1; y < ds->h+1; y++) {
-        stale = FALSE;
-        xy = x+y*(state->common->params.w+2);
-        xi = state->common->xinfo[xy];
-        c = state->common->grid[xy];
+        for (y = 1; y < ds->h+1; y++) {
+            stale = FALSE;
+            xy = x+y*(state->common->params.w+2);
+            xi = state->common->xinfo[xy];
+            c = state->common->grid[xy];
     
-        if (!ds->started) stale = TRUE;
-        if (ds->hflash != hflash) stale = TRUE;
-        if (ds->ascii != ui->ascii) stale = TRUE;
+            if (!ds->started) stale = TRUE;
+            if (ds->hflash != hflash) stale = TRUE;
+            if (changed_ascii) stale = TRUE;
         
-        if (hchanged) {
-            if ((x == ui->hx && y == ui->hy) ||
-                (x == ds->hx && y == ds->hy))
-                stale = TRUE;
-        }
+            if (hchanged) {
+                if ((x == ui->hx && y == ui->hy) ||
+                    (x == ds->hx && y == ds->hy))
+                    stale = TRUE;
+            }
 
-        if (xi >= 0 && (state->guess[xi] != ds->monsters[xi]) ) {
-            stale = TRUE;
-            ds->monsters[xi] = state->guess[xi];
-        }
+            if (xi >= 0 && (state->guess[xi] != ds->monsters[xi]) ) {
+                stale = TRUE;
+                ds->monsters[xi] = state->guess[xi];
+            }
         
-        if (xi >= 0 && (state->pencils[xi] != ds->pencils[xi]) ) {
-            stale = TRUE;
-            ds->pencils[xi] = state->pencils[xi];
-        }
+            if (xi >= 0 && (state->pencils[xi] != ds->pencils[xi]) ) {
+                stale = TRUE;
+                ds->pencils[xi] = state->pencils[xi];
+            }
 
-        if (state->cell_errors[xy] != ds->cell_errors[xy]) {
-            stale = TRUE;
-            ds->cell_errors[xy] = state->cell_errors[xy];
-        }
+            if (state->cell_errors[xy] != ds->cell_errors[xy]) {
+                stale = TRUE;
+                ds->cell_errors[xy] = state->cell_errors[xy];
+            }
                 
-        if (stale) {
-            draw_cell_background(dr, ds, state, ui, x, y);
-            if (xi < 0) 
-                draw_mirror(dr, ds, state, x, y, hflash, c);
-            else if (state->guess[xi] == 1 || state->guess[xi] == 2 ||
-                     state->guess[xi] == 4)
-                draw_big_monster(dr, ds, state, x, y, hflash, state->guess[xi]);
-            else 
-                draw_pencils(dr, ds, state, x, y, state->pencils[xi]);
+            if (stale) {
+                draw_cell_background(dr, ds, state, ui, x, y);
+                if (xi < 0) 
+                    draw_mirror(dr, ds, state, x, y, hflash, c);
+                else if (state->guess[xi] == 1 || state->guess[xi] == 2 ||
+                         state->guess[xi] == 4)
+                    draw_big_monster(dr, ds, state, x, y, hflash, state->guess[xi]);
+                else 
+                    draw_pencils(dr, ds, state, x, y, state->pencils[xi]);
+            }
         }
-    }
 
     ds->hx = ui->hx; ds->hy = ui->hy;
     ds->hshow = ui->hshow;
     ds->hpencil = ui->hpencil;
     ds->hflash = hflash;
-    ui->ascii = ds->ascii;
     ds->started = TRUE;
     return;
 }
@@ -2591,4 +2607,3 @@ const struct game thegame = {
     FALSE, game_timing_state,
     0,                     /* flags */
 };
-