pets getting "stuck" trying to reach inaccessible objects

Incorporate a slightly modified version of a patch submitted by <Someone> back in June.  The basic problem, which I noticed again this past
weekend, is that pets with a high apport value can still try to get to
objects when there's no path to the object.  The patch extends the
can_reach_food function to be used for any object, renaming it to
can_reach_location, and adds a could_reach_item function for doing point
checks.  This also removes any chance of a pet dragon, for example, eating
something underwater.

diff --git a/doc/fixes34.3 b/doc/fixes34.3
index 9f624714159aa3745e42c2fb80798045e1c50aa9..ba2a7c765f5f08950bc0a933f760bc16e444fbd0 100644 (file)
--- a/doc/fixes34.3
+++ b/doc/fixes34.3
@@ -65,6 +65,7 @@ traveling while standing on a trap would sometime step in the wrong direction
 avoid traveling into water/lava, using usual running rules
 unchanging iron golem would still rehumanize in a rust trap
 fix an impossible rndmonst: bad `mndx' bug
+pets should not try to go after objects that they can't reach
 
 
 Platform- and/or Interface-Specific Fixes

diff --git a/src/dogmove.c b/src/dogmove.c
index 368d286ae815f2885504418e96b3a1610f1e4c63..2dd36f3394eb1b9a1c66b2484630acaea610b994 100644 (file)
--- a/src/dogmove.c
+++ b/src/dogmove.c
@@ -14,8 +14,9 @@ STATIC_DCL int FDECL(dog_invent,(struct monst *,struct edog *,int));
 STATIC_DCL int FDECL(dog_goal,(struct monst *,struct edog *,int,int,int));
 
 STATIC_DCL struct obj *FDECL(DROPPABLES, (struct monst *));
-STATIC_DCL boolean FDECL(can_reach_food,(struct monst *,XCHAR_P,XCHAR_P,XCHAR_P,
-    XCHAR_P));
+STATIC_DCL boolean FDECL(can_reach_location,(struct monst *,XCHAR_P,XCHAR_P,
+    XCHAR_P,XCHAR_P));
+STATIC_DCL boolean FDECL(could_reach_item,(struct monst *, XCHAR_P,XCHAR_P));
 
 STATIC_OVL struct obj *
 DROPPABLES(mon)
@@ -285,13 +286,14 @@ int udist;
                                                                        ){
                int edible = dogfood(mtmp, obj);
 
-               if (edible <= CADAVER ||
+               if ((edible <= CADAVER ||
                        /* starving pet is more aggressive about eating */
-                       (edog->mhpmax_penalty && edible == ACCFOOD))
+                       (edog->mhpmax_penalty && edible == ACCFOOD)) &&
+                   could_reach_item(mtmp, obj->ox, obj->oy))
                    return dog_eat(mtmp, obj, omx, omy, FALSE);
 
                if(can_carry(mtmp, obj) && !obj->cursed &&
-                       !is_pool(mtmp->mx,mtmp->my)) {
+                       could_reach_item(mtmp, obj->ox, obj->oy)) {
                    if(rn2(20) < edog->apport+3) {
                        if (rn2(udist) || !rn2(edog->apport)) {
                            if (cansee(omx, omy) && flags.verbose)
@@ -372,8 +374,11 @@ int after, udist, whappr;
                    if (cursed_object_at(nx, ny) &&
                            !(edog->mhpmax_penalty && otyp < MANFOOD))
                        continue;
-                   if (otyp < MANFOOD &&
-                           can_reach_food(mtmp, mtmp->mx, mtmp->my, nx, ny)) {
+                   /* skip completely unreacheable goals */
+                   if (!could_reach_item(mtmp, nx, ny) ||
+                       !can_reach_location(mtmp, mtmp->mx, mtmp->my, nx, ny))
+                       continue;
+                   if (otyp < MANFOOD) {
                        if (otyp < gtyp || DDIST(nx,ny) < DDIST(gx,gy)) {
                            gx = nx;
                            gy = ny;
@@ -780,15 +785,28 @@ dognext:
        return(1);
 }
 
-/* Hack to prevent a dog from being endlessly stuck near a piece of food that
+/* check if a monster could pick up objects from a location */
+STATIC_OVL boolean
+could_reach_item(mon, nx, ny)
+struct monst *mon;
+xchar nx, ny;
+{
+    if ((!is_pool(nx,ny) || is_swimmer(mon->data)) &&
+       (!is_lava(nx,ny) || likes_lava(mon->data)) &&
+       (!sobj_at(BOULDER,nx,ny) || throws_rocks(mon->data)))
+       return TRUE;
+    return FALSE;
+}
+
+/* Hack to prevent a dog from being endlessly stuck near an object that
  * it can't reach, such as caught in a teleport scroll niche.  It recursively
- * checks to see if the squares inbetween are good.  The checking could be a
+ * checks to see if the squares in between are good.  The checking could be a
  * little smarter; a full check would probably be useful in m_move() too.
  * Since the maximum food distance is 5, this should never be more than 5 calls
  * deep.
  */
-STATIC_OVL  boolean
-can_reach_food(mon, mx, my, fx, fy)
+STATIC_OVL boolean
+can_reach_location(mon, mx, my, fx, fy)
 struct monst *mon;
 xchar mx, my, fx, fy;
 {
@@ -811,13 +829,9 @@ xchar mx, my, fx, fy;
            if (IS_DOOR(levl[i][j].typ) &&
                                (levl[i][j].doormask & (D_CLOSED | D_LOCKED)))
                continue;
-           if (is_pool(i, j) && !is_swimmer(mon->data))
-               continue;
-           if (is_lava(i, j) && !likes_lava(mon->data))
-               continue;
-           if (sobj_at(BOULDER,i,j) && !throws_rocks(mon->data))
+           if (!could_reach_item(mon, i, j))
                continue;
-           if (can_reach_food(mon, i, j, fx, fy))
+           if (can_reach_location(mon, i, j, fx, fy))
                return TRUE;
        }
     }