Make monster destroy armor -spell erode armor first

Instead of outright destroying the armor, the spell will instead
first erode the armor.  The spell hits 2-4 times, so if it hits
the same armor 4 times, it will get destroyed.  This does not
hit erodeproof armor.

Also change the scroll of destroy armor, so that blessed one will
destroy a cursed armor, if hero is only wearing that.

doc/fixes3-7-0.txt

@@ -2890,12 +2890,15 @@ enlightenment/attribute disclosure for saving-grace: include a line for have
 tourists gain experience by "taking photos" of new creatures, and
 	going to new dungeon levels
 healers gain experience by healing pets
-blessed scroll of destroy armor asks which armor to destroy
+blessed scroll of destroy armor asks which armor to destroy if wearing more
+	than one armor; otherwise it'll destroy a cursed armor, or erodes
+	random armor
 archeologists' fedora is lucky
 telepathic hero can discern which particular monster just read a scroll
 add "make fetch-docs" to download pre-formatted documentation
 monsters will use throw-and-return weapons such as an aklys
 archeologists can identify scrolls by deciphering their labels
+monster destroy armor -spell first erodes armor
 
 
 Platform- and/or Interface-Specific New Features

include/extern.h

@@ -766,7 +766,8 @@ extern struct obj *unchanger(void);
 extern void reset_remarm(void);
 extern int doddoremarm(void);
 extern int remarm_swapwep(void);
-extern int destroy_arm(struct obj *);
+extern int disintegrate_arm(struct obj *);
+extern int destroy_arm(void);
 extern void adj_abon(struct obj *, schar) NONNULLARG1;
 extern boolean inaccessible_equipment(struct obj *, const char *, boolean);
 extern int any_worn_armor_ok(struct obj *);

include/obj.h

@@ -451,6 +451,7 @@ struct obj {
 #define BURIED_TOO 0x2
 
 /* object erosion types */
+#define ERODE_NONE -1
 #define ERODE_BURN 0
 #define ERODE_RUST 1
 #define ERODE_ROT 2

src/do_wear.c

@@ -52,6 +52,7 @@ staticfn int takeoff_ok(struct obj *);
 /* maybe_destroy_armor() may return NULL */
 staticfn struct obj *maybe_destroy_armor(struct obj *, struct obj *,
                                        boolean *) NONNULLARG3;
+staticfn int obj_erode_type(struct obj *) NONNULLARG1;
 staticfn boolean better_not_take_that_off(struct obj *) NONNULLARG1;
 
 /* plural "fingers" or optionally "gloves" */
@@ -3191,9 +3192,9 @@ maybe_destroy_armor(struct obj *armor, struct obj *atmp, boolean *resisted)
     return (struct obj *) 0;
 }
 
-/* hit by destroy armor scroll/black dragon breath/monster spell */
+/* hit by destroy armor scroll/black dragon breath */
 int
-destroy_arm(struct obj *atmp)
+disintegrate_arm(struct obj *atmp)
 {
     struct obj *otmp = (struct obj *) 0;
     boolean losing_gloves = FALSE, resisted = FALSE,
@@ -3250,6 +3251,66 @@ destroy_arm(struct obj *atmp)
     return 1;
 }
 
+/* return ERODE_foo erosion type which can apply to object */
+staticfn int
+obj_erode_type(struct obj *otmp)
+{
+    if (is_flammable(otmp))
+        return ERODE_BURN;
+    else if (is_rustprone(otmp))
+        return ERODE_RUST;
+    else if (is_crackable(otmp))
+        return ERODE_CRACK;
+    else if (is_rottable(otmp))
+        return ERODE_ROT;
+    else if (is_corrodeable(otmp))
+        return ERODE_CORRODE;
+    return ERODE_NONE;
+}
+
+/* erode a number of worn armor(s).
+   if the armor is hit when max eroded, destroys it. */
+int
+destroy_arm(void)
+{
+    struct obj *armors[7] = { NULL };
+    struct obj *otmp;
+    int i, idx = 0, hits = rn2(4) + 1;
+    int ret = 0;
+
+    /* gather worn armor; include non-erodeable ones */
+    if (uarm) armors[idx++] = uarm;
+    if (uarmc) armors[idx++] = uarmc;
+    if (uarmh) armors[idx++] = uarmh;
+    if (uarms) armors[idx++] = uarms;
+    if (uarmg) armors[idx++] = uarmg;
+    if (uarmf) armors[idx++] = uarmf;
+    if (uarmu) armors[idx++] = uarmu;
+    if (!idx)
+        return 0;
+
+    for (i = 0; i < hits; i++) {
+        otmp = armors[rn2(idx)];
+
+        if (erosion_matters(otmp) && is_damageable(otmp) && !otmp->oerodeproof) {
+            int erosion = obj_erode_type(otmp);
+
+            if (erosion != ERODE_NONE) {
+                int r = erode_obj(otmp, xname(otmp), erosion, EF_PAY|EF_DESTROY);
+
+                if (r != ER_NOTHING)
+                    ret = 1;
+                if (r == ER_DESTROYED)
+                    break;
+            }
+        }
+    }
+
+    if (ret)
+        stop_occupation();
+    return ret;
+}
+
 void
 adj_abon(struct obj *otmp, schar delta)
 {

src/mcastu.c

@@ -530,7 +530,7 @@ cast_wizard_spell(struct monst *mtmp, int dmg, int spellnum)
             shieldeff(u.ux, u.uy);
             monstseesu(M_SEEN_MAGR);
             pline("A field of force surrounds you!");
-        } else if (!destroy_arm(some_armor(&gy.youmonst))) {
+        } else if (!destroy_arm()) {
             Your("skin itches.");
         } else {
             /* monsters only realize you aren't magic-protected if armor is

src/pray.c

@@ -660,15 +660,15 @@ god_zaps_you(aligntyp resp_god)
          */
         if (uarms && !(EReflecting & W_ARMS)
             && !(EDisint_resistance & W_ARMS))
-            (void) destroy_arm(uarms);
+            (void) disintegrate_arm(uarms);
         if (uarmc && !(EReflecting & W_ARMC)
             && !(EDisint_resistance & W_ARMC))
-            (void) destroy_arm(uarmc);
+            (void) disintegrate_arm(uarmc);
         if (uarm && !(EReflecting & W_ARM) && !(EDisint_resistance & W_ARM)
             && !uarmc)
-            (void) destroy_arm(uarm);
+            (void) disintegrate_arm(uarm);
         if (uarmu && !uarm && !uarmc)
-            (void) destroy_arm(uarmu);
+            (void) disintegrate_arm(uarmu);
         if (!Disint_resistance) {
             fry_by_god(resp_god, TRUE);
             monstunseesu(M_SEEN_DISINT);

src/read.c

@@ -22,6 +22,7 @@ staticfn int maybe_tame(struct monst *, struct obj *);
 staticfn boolean can_center_cloud(coordxy, coordxy);
 staticfn void display_stinking_cloud_positions(boolean);
 staticfn void seffect_enchant_armor(struct obj **);
+staticfn boolean disintegrate_cursed_armor(void);
 staticfn void seffect_destroy_armor(struct obj **);
 staticfn void seffect_confuse_monster(struct obj **);
 staticfn void seffect_scare_monster(struct obj **);
@@ -1281,6 +1282,29 @@ seffect_enchant_armor(struct obj **sobjp)
               Blind ? "again" : "unexpectedly");
 }
 
+/* destroy a random cursed armor worn by hero */
+staticfn boolean
+disintegrate_cursed_armor(void)
+{
+    struct obj *armors[7] = { NULL };
+    int idx = 0;
+
+    if (uarm && uarm->cursed) armors[idx++] = uarm;
+    if (uarmc && uarmc->cursed) armors[idx++] = uarmc;
+    if (uarmh && uarmh->cursed) armors[idx++] = uarmh;
+    if (uarms && uarms->cursed) armors[idx++] = uarms;
+    if (uarmg && uarmg->cursed) armors[idx++] = uarmg;
+    if (uarmf && uarmf->cursed) armors[idx++] = uarmf;
+    if (uarmu && uarmu->cursed) armors[idx++] = uarmu;
+    if (!idx)
+        return FALSE;
+
+    if (disintegrate_arm(armors[rn2(idx)]))
+        return TRUE;
+
+    return FALSE;
+}
+
 staticfn void
 seffect_destroy_armor(struct obj **sobjp)
 {
@@ -1310,7 +1334,21 @@ seffect_destroy_armor(struct obj **sobjp)
         otmp->oerodeproof = new_erodeproof ? 1 : 0;
         return;
     }
-    if (!scursed || !otmp || !otmp->cursed) {
+
+    if (scursed) {
+        if (otmp && otmp->cursed) {
+            /* armor and scroll both cursed */
+            pline("%s.", Yobjnam2(otmp, "vibrate"));
+            if (otmp->spe >= -6) {
+                otmp->spe += -1;
+                adj_abon(otmp, -1);
+            }
+            make_stunned((HStun & TIMEOUT) + (long) rn1(10, 10), TRUE);
+        } else if (disintegrate_arm(otmp)) {
+            gk.known = TRUE;
+            return;
+        }
+    } else {
         boolean gets_choice = (otmp && sobj && sobj->blessed
                                && count_worn_armor() > 1);
 
@@ -1324,9 +1362,14 @@ seffect_destroy_armor(struct obj **sobjp)
             /* check the return value, if user picked non-valid obj */
             if (any_worn_armor_ok(atmp) == GETOBJ_SUGGEST)
                 otmp = atmp;
-        }
-
-        if (!destroy_arm(otmp)) {
+            if (disintegrate_arm(otmp)) {
+                gk.known = TRUE;
+                return;
+            }
+        } else if (sobj->blessed && disintegrate_cursed_armor()) {
+            gk.known = TRUE;
+            return;
+        } else if (!destroy_arm()) {
             strange_feeling(sobj, "Your skin itches.");
             *sobjp = 0; /* useup() in strange_feeling() */
             exercise(A_STR, FALSE);
@@ -1334,13 +1377,6 @@ seffect_destroy_armor(struct obj **sobjp)
             return;
         } else
             gk.known = TRUE;
-    } else { /* armor and scroll both cursed */
-        pline("%s.", Yobjnam2(otmp, "vibrate"));
-        if (otmp->spe >= -6) {
-            otmp->spe += -1;
-            adj_abon(otmp, -1);
-        }
-        make_stunned((HStun & TIMEOUT) + (long) rn1(10, 10), TRUE);
     }
 }
 

src/zap.c

@@ -4462,21 +4462,21 @@ zhitu(
             monstunseesu(M_SEEN_DISINT);
             if (uarms) {
                 /* destroy shield; other possessions are safe */
-                (void) destroy_arm(uarms);
+                (void) disintegrate_arm(uarms);
                 break;
             } else if (uarm) {
                 /* destroy suit; if present, cloak goes too */
                 if (uarmc)
-                    (void) destroy_arm(uarmc);
-                (void) destroy_arm(uarm);
+                    (void) disintegrate_arm(uarmc);
+                (void) disintegrate_arm(uarm);
                 break;
             }
             /* no shield or suit, you're dead; wipe out cloak
                and/or shirt in case of life-saving or bones */
             if (uarmc)
-                (void) destroy_arm(uarmc);
+                (void) disintegrate_arm(uarmc);
             if (uarmu)
-                (void) destroy_arm(uarmu);
+                (void) disintegrate_arm(uarmu);
         } else if (nonliving(gy.youmonst.data) || is_demon(gy.youmonst.data)) {
             shieldeff(sx, sy);
             You("seem unaffected.");