Electrocution discharge in water ala FR 1637214

Weapons of electrocution now discharge in water, if the target is
touching the water and not rElec, hitting all adjacent
water-touching non-rElec creatures for about half the normal
electrocution damage.

Particularly notable new code is the implementation of an
area-of-effect callback for beams, as well as a function and
structure for weapon effects that should only happen after the
target would have died, if it was going to die, and therefore
cannot safely make use of its data.

Issues that still need to be decided:
- How doe Xom feel about this? (eg. If creatures hurt themselves
  this way.)
- Should it ask you if you want to attack when you know the
  discharge will hit yourself?

1 files changed, 43 insertions, 6 deletions

diff --git a/crawl-ref/source/fight.cc b/crawl-ref/source/fight.cc
index 522ad3dbe5..9606b308ac 100644
--- a/crawl-ref/source/fight.cc
+++ b/crawl-ref/source/fight.cc
@@ -353,7 +353,7 @@ melee_attack::melee_attack(actor *attk, actor *defn,
       shield(NULL), defender_shield(NULL),
       heavy_armour_penalty(0), can_do_unarmed(false),
       water_attack(false), miscast_level(-1), miscast_type(SPTYP_NONE),
-      miscast_target(NULL)
+      miscast_target(NULL), final_effects()
 {
     init_attack();
 }
@@ -1887,6 +1887,29 @@ void melee_attack::player_check_weapon_effects()
     }
 }
 
+// Effects that occur after all other effects, even if the monster is dead.
+// For example, explosions that would hit other creatures, but we want
+// to deal with only one creature at a time, so that's handled last.
+// You probably want to call player_monattk_hit_effects instead, as that
+// function calls this one.
+// Returns true if the combat round should end here.
+bool melee_attack::player_monattk_final_hit_effects(bool mondied)
+{
+    for (unsigned int i = 0; i < final_effects.size(); ++i)
+    {
+        switch (final_effects[i].flavor)
+        {
+        case FINEFF_LIGHTNING_DISCHARGE:
+            if (see_cell(final_effects[i].location))
+                mpr("Electricity arcs through the water!");
+            conduct_electricity(final_effects[i].location, attacker);
+            break;
+        }
+    }
+
+    return mondied;
+}
+
 // Returns true if the combat round should end here.
 bool melee_attack::player_monattk_hit_effects(bool mondied)
 {
@@ -1932,7 +1955,7 @@ bool melee_attack::player_monattk_hit_effects(bool mondied)
     }
 
     if (mondied)
-        return (true);
+        return player_monattk_final_hit_effects(true);
 
     // These effects apply only to monsters that are still alive:
 
@@ -1943,14 +1966,14 @@ bool melee_attack::player_monattk_hit_effects(bool mondied)
     // Also returns true if the hydra's last head was cut off, in which
     // case nothing more should be done to the hydra.
     if (decapitate_hydra(damage_done))
-        return (!defender->alive());
+        return player_monattk_final_hit_effects(!defender->alive());
 
     // These two (staff damage and damage brand) are mutually exclusive!
     player_apply_staff_damage();
 
     // Returns true if the monster croaked.
     if (!special_damage && apply_damage_brand())
-        return (true);
+        return player_monattk_final_hit_effects(true);
 
     if (!no_damage_message.empty())
     {
@@ -1984,10 +2007,10 @@ bool melee_attack::player_monattk_hit_effects(bool mondied)
     {
         _monster_die(defender_as_monster(), KILL_YOU, NON_MONSTER);
 
-        return (true);
+        return player_monattk_final_hit_effects(true);
     }
 
-    return (false);
+    return player_monattk_final_hit_effects(false);
 }
 
 void melee_attack::_monster_die(monsters* monster, killer_type killer,
@@ -3073,7 +3096,21 @@ bool melee_attack::apply_damage_brand()
                    "You are electrocuted!"
                 :  "There is a sudden explosion of sparks!";
             special_damage = 10 + random2(15);
+
+            // Check for arcing in water, and add the final effect.
+            const coord_def& pos = defender->pos();
+
+            // We know the defender is neither airborne nor electricity
+            // resistant, from above, but is it on water?
+            if (feat_is_water(grd(pos)))
+            {
+                attack_final_effect effect;
+                effect.flavor = FINEFF_LIGHTNING_DISCHARGE;
+                effect.location = pos;
+                final_effects.push_back(effect);
+            }
         }
+
         break;
 
     case SPWPN_ORC_SLAYING: