And generalize them a bit more.

git-svn-id: https://crawl-ref.svn.sourceforge.net/svnroot/crawl-ref/trunk@4651 c06c8d41-db1a-0410-9941-cceddc491573

4 files changed, 15 insertions, 12 deletions

diff --git a/crawl-ref/source/beam.cc b/crawl-ref/source/beam.cc
index bc89d8d296..69db2e76e9 100644
--- a/crawl-ref/source/beam.cc
+++ b/crawl-ref/source/beam.cc
@@ -4215,13 +4215,13 @@ static int _affect_monster_enchantment(bolt &beam, monsters *mon)
 
     if (beam.flavour == BEAM_POLYMORPH)
     {
-        if (mons_holiness( mon ) != MH_NATURAL)
+        if (!mon->can_mutate())
             return (MON_UNAFFECTED);
 
         if (check_mons_resist_magic( mon, beam.ench_power ))
             return mons_immune_magic(mon) ? MON_UNAFFECTED : MON_RESIST;
 
-        if (monster_polymorph(mon, RANDOM_MONSTER))
+        if (mon->mutate())
             beam.obvious_effect = true;
 
         if (YOU_KILL(beam.thrower))
diff --git a/crawl-ref/source/externs.h b/crawl-ref/source/externs.h
index b9aa5700c5..27ca15cc87 100644
--- a/crawl-ref/source/externs.h
+++ b/crawl-ref/source/externs.h
@@ -149,7 +149,7 @@ public:
     virtual void go_berserk(bool intentional) = 0;
     virtual bool can_mutate() const = 0;
     virtual bool can_safely_mutate() const = 0;
-    virtual void mutate() = 0;
+    virtual bool mutate() = 0;
     virtual int hurt(const actor *attacker, int amount) = 0;
     virtual void heal(int amount, bool max_too = false) = 0;
     virtual void banish(const std::string &who = "") = 0;
@@ -843,7 +843,7 @@ public:
     void go_berserk(bool intentional);
     bool can_mutate() const;
     bool can_safely_mutate() const;
-    void mutate();
+    bool mutate();
     void banish(const std::string &who = "");
     void blink();
     void teleport(bool right_now = false, bool abyss_shift = false);
@@ -1167,7 +1167,7 @@ public:
     void go_berserk(bool intentional);
     bool can_mutate() const;
     bool can_safely_mutate() const;
-    void mutate();
+    bool mutate();
     void banish(const std::string &who = "");
     void expose_to_element(beam_type element, int strength = 0);
     bool visible() const;
diff --git a/crawl-ref/source/mon-util.cc b/crawl-ref/source/mon-util.cc
index 71a5207e36..4c98d801f6 100644
--- a/crawl-ref/source/mon-util.cc
+++ b/crawl-ref/source/mon-util.cc
@@ -5441,12 +5441,12 @@ bool monsters::can_safely_mutate() const
     return (can_mutate());
 }
 
-void monsters::mutate()
+bool monsters::mutate()
 {
     if (!can_mutate())
-        return;
+        return false;
 
-    monster_polymorph(this, RANDOM_MONSTER);
+    return (monster_polymorph(this, RANDOM_MONSTER));
 }
 
 bool monsters::is_icy() const
diff --git a/crawl-ref/source/player.cc b/crawl-ref/source/player.cc
index 84ccd266c6..401ae4cde5 100644
--- a/crawl-ref/source/player.cc
+++ b/crawl-ref/source/player.cc
@@ -6458,18 +6458,21 @@ bool player::can_safely_mutate() const
                     && you.hunger_state == HS_ENGORGED)));
 }
 
-void player::mutate()
+bool player::mutate()
 {
     if (!can_mutate())
-        return;
+        return false;
 
     if (one_chance_in(5))
     {
         if (::mutate(RANDOM_MUTATION))
+        {
             learned_something_new(TUT_YOU_MUTATED);
+            return true;
+        }
     }
-    else
-        give_bad_mutation();
+
+    return give_bad_mutation();
 }
 
 bool player::is_icy() const