Conjure Ball Lightning adjustments

The reduced CBL duration was so low that the ball lightning would
frequently explode before even being able to reach targets in your
LoS (or before you could step away, even if you did so immediately
on open ground). This commit restores the old duration and makes
a few other changes to reduce power level instead:

Ball lightning conjured with less spellpower explode for less damage
(and their explosion is less likely to be radius 3), the number of
ball lightning conjured per cast has been reduced (and the variance
decreased somewhat), and ball lightning which leave the player's
line of sight immediately dissipate without exploding (so that it
is no longer possible to aim them at things you cannot see and cannot
harm you). The aim is that this will make it impractical against
monsters out of sight, while being less awkward against those IN
sight (and less likely to immediately engulf the caster before being
able to reach anything else).

1 files changed, 10 insertions, 0 deletions

diff --git a/crawl-ref/source/mon-act.cc b/crawl-ref/source/mon-act.cc
index abea14b995..59214b6441 100644
--- a/crawl-ref/source/mon-act.cc
+++ b/crawl-ref/source/mon-act.cc
@@ -31,6 +31,7 @@
 #include "item_use.h"
 #include "libutil.h"
 #include "los.h"
+#include "losglobal.h"
 #include "mapmark.h"
 #include "message.h"
 #include "misc.h"
@@ -1744,6 +1745,15 @@ static void _pre_monster_move(monster* mons)
         }
     }
 
+    // Dissipate player ball lightnings that have left the player's sight
+    // (monsters are allowed to 'cheat', as with orb of destruction)
+    if (mons->type == MONS_BALL_LIGHTNING && mons->summoner == MID_PLAYER
+        && !cell_see_cell(you.pos(), mons->pos(), LOS_SOLID))
+    {
+        monster_die(mons, KILL_RESET, NON_MONSTER);
+        return;
+    }
+
     if (mons_stores_tracking_data(mons))
     {
         actor* foe = mons->get_foe();