Implemented Erik's invisibility proposal:

- M_SENSE_INVIS for perceptive monsters; split existing monsters with see
  invisible into M_SEE_INVIS and M_SENSE_INVIS.
- Monsters that can't see invisible get to-hit penalties vs invisible players 
  and monsters in both melee and at range.
- Monsters that sense where you are know where to shoot and attack, but still
  get to-hit penalties because they don't know exactly where you are.

git-svn-id: https://crawl-ref.svn.sourceforge.net/svnroot/crawl-ref/trunk@1260 c06c8d41-db1a-0410-9941-cceddc491573

1 files changed, 20 insertions, 6 deletions

diff --git a/crawl-ref/source/mon-util.cc b/crawl-ref/source/mon-util.cc
index 086a63bd15..7c0da9cf5d 100644
--- a/crawl-ref/source/mon-util.cc
+++ b/crawl-ref/source/mon-util.cc
@@ -519,16 +519,21 @@ bool mons_is_unique( int mc )
     return (mons_class_flag(mc, M_UNIQUE));
 }
 
-char mons_see_invis( struct monsters *mon )
+bool mons_sense_invis(const monsters *mon)
+{
+    return (mons_class_flag(mon->type, M_SENSE_INVIS));
+}
+
+bool mons_see_invis(const monsters *mon)
 {
     if (mon->type == MONS_PLAYER_GHOST || mon->type == MONS_PANDEMONIUM_DEMON)
         return (mon->ghost->values[ GVAL_SEE_INVIS ]);
     else if (((seekmonster(mon->type))->bitfields & M_SEE_INVIS) != 0)
-        return (1);
+        return (true);
     else if (scan_mon_inv_randarts( mon, RAP_EYESIGHT ) > 0)
-        return (1);
+        return (true);
 
-    return (0);
+    return (false);
 }                               // end mons_see_invis()
 
 
@@ -554,7 +559,7 @@ bool mons_player_visible( struct monsters *mon )
         if (player_in_water())
             return (true);
 
-        if (mons_see_invis( mon ))
+        if (mons_see_invis( mon ) || mons_sense_invis(mon))
             return (true);
 
         return (false);
@@ -568,7 +573,6 @@ unsigned char mons_char(int mc)
     return (unsigned char) smc->showchar;
 }                               // end mons_char()
 
-
 char mons_itemuse(int mc)
 {
     return (smc->gmon_use);
@@ -3859,6 +3863,16 @@ bool monsters::needs_berserk(bool check_spells) const
     return (true);
 }
 
+bool monsters::can_see_invisible() const
+{
+    return (mons_see_invis(this));
+}
+
+bool monsters::invisible() const
+{
+    return (has_ench(ENCH_INVIS));
+}
+
 /////////////////////////////////////////////////////////////////////////
 // mon_enchant