Shaft trap behavior modified. They now are one-time use and pre-knowledge of shaft traps (i.e. using them intentionally) will improve the chances of the player landing fewer levels away. Shaft traps also now randomly determine their destination. Monsters cannot follow the player through shaft traps.

Signed-off-by: David Ploog <dploog@users.sourceforge.net>

7 files changed, 49 insertions, 60 deletions

diff --git a/crawl-ref/source/actor.cc b/crawl-ref/source/actor.cc
index 1a79413525..16e67aed3b 100644
--- a/crawl-ref/source/actor.cc
+++ b/crawl-ref/source/actor.cc
@@ -30,9 +30,9 @@ bool actor::will_trigger_shaft() const
     return (!airborne() && total_weight() > 0 && is_valid_shaft_level());
 }
 
-level_id actor::shaft_dest() const
+level_id actor::shaft_dest(bool known = false) const
 {
-    return generic_shaft_dest(pos());
+    return generic_shaft_dest(pos(), known);
 }
 
 bool actor::airborne() const
diff --git a/crawl-ref/source/actor.h b/crawl-ref/source/actor.h
index 97e65922cb..a4d76ef56e 100644
--- a/crawl-ref/source/actor.h
+++ b/crawl-ref/source/actor.h
@@ -248,7 +248,7 @@ public:
     virtual bool has_spell(spell_type spell) const = 0;
 
     virtual bool     will_trigger_shaft() const;
-    virtual level_id shaft_dest() const;
+    virtual level_id shaft_dest(bool known) const;
     virtual bool     do_shaft() = 0;
 
     coord_def position;
diff --git a/crawl-ref/source/misc.cc b/crawl-ref/source/misc.cc
index 54456fc8a5..b5182b278b 100644
--- a/crawl-ref/source/misc.cc
+++ b/crawl-ref/source/misc.cc
@@ -2213,7 +2213,7 @@ void down_stairs( int old_level, dungeon_feature_type force_stair,
             return;
         }
 
-        shaft_dest = you.shaft_dest();
+        shaft_dest = you.shaft_dest(known_trap);
         if (shaft_dest == level_id::current())
         {
             if (known_trap)
@@ -2230,6 +2230,10 @@ void down_stairs( int old_level, dungeon_feature_type force_stair,
 
         if (you.flight_mode() != FL_FLY || force_stair)
             mpr("You fall through a shaft!");
+
+        // Shafts are one-time-use.
+        mpr("The shaft crumbles and collapses!");
+        find_trap(you.pos())->destroy();
     }
 
     if (stair_find == DNGN_ENTER_ZOT && !you.opened_zot)
diff --git a/crawl-ref/source/monster.cc b/crawl-ref/source/monster.cc
index ad1d1b499c..abedfba501 100644
--- a/crawl-ref/source/monster.cc
+++ b/crawl-ref/source/monster.cc
@@ -5564,7 +5564,7 @@ bool monsters::do_shaft()
         }
     }
 
-    level_id lev = shaft_dest();
+    level_id lev = shaft_dest(false);
 
     if (lev == level_id::current())
         return (false);
diff --git a/crawl-ref/source/player.cc b/crawl-ref/source/player.cc
index e36fd474e6..be27606499 100644
--- a/crawl-ref/source/player.cc
+++ b/crawl-ref/source/player.cc
@@ -203,10 +203,10 @@ bool move_player_to_grid( const coord_def& p, bool stepped, bool allow_shift,
 #ifdef CLUA_BINDINGS
                      // Prompt for any trap where you might not have enough hp
                      // as defined in init.txt (see trapwalk.lua)
-                     if (new_grid != DNGN_TRAP_MECHANICAL
-                            && type != TRAP_SHAFT
+                     if (type != TRAP_SHAFT // Known shafts aren't traps
+                         && (new_grid != DNGN_TRAP_MECHANICAL
                          || !clua.callbooleanfn(false, "ch_cross_trap",
-                                                "s", trap_name(p)))
+                                                "s", trap_name(p))))
 #endif
                 {
                     std::string prompt = make_stringf(
@@ -7309,7 +7309,6 @@ bool player::do_shaft()
             return (false);
         }
 
-        mpr("A shaft briefly opens up underneath you!");
         handle_items_on_shaft(this->pos(), false);
 
         if (airborne() || total_weight() == 0)
diff --git a/crawl-ref/source/traps.cc b/crawl-ref/source/traps.cc
index a8d47fa834..4251ffe78f 100644
--- a/crawl-ref/source/traps.cc
+++ b/crawl-ref/source/traps.cc
@@ -626,6 +626,9 @@ void trap_def::trigger(actor& triggerer, bool flat_footed)
         break;
 
     case TRAP_SHAFT:
+        // Unknown shafts are traps triggered by walking onto them.
+        // Known shafts are used as escape hatches
+
         // Paranoia
         if (!is_valid_shaft_level())
         {
@@ -636,48 +639,19 @@ void trap_def::trigger(actor& triggerer, bool flat_footed)
             break;
         }
 
+        // If the shaft isn't triggered, don't reveal it.
+        if (!triggerer.will_trigger_shaft() && !you_know)
+            this->hide();
+
         // Known shafts don't trigger as traps.
         if (trig_knows)
-        {
-            if (you_trigger)
-            {
-               if (triggerer.airborne())
-               {
-                   if (you.flight_mode() == FL_LEVITATE)
-                       mpr("You float over the shaft.");
-                   else
-                       mpr("You fly over the shaft.");
-               }
-               else
-                   mpr("You carefully avoid triggering the shaft.");
-            }
             break;
-        }
-
-        if (!triggerer.will_trigger_shaft())
-        {
-            if (!you_know)
-                this->hide();
-            else if (!triggerer.airborne())
-            {
-                if (you_trigger)
-                {
-                    mpr("You don't fall through the shaft.");
-                }
-                else if (m)
-                {
-                    simple_monster_message(m,
-                                           " doesn't fall through the shaft.");
-                }
-            }
-        }
 
         // Fire away!
-        {
-            const bool revealed = triggerer.do_shaft();
-            if (!revealed && !you_know)
-                this->hide();
-        }
+        triggerer.do_shaft();
+
+        // Shafts are destroyed
+        // after one use in down_stairs(), misc.cc
         break;
 
     default:
@@ -1341,10 +1315,10 @@ bool is_valid_shaft_level(const level_id &place)
     return ((branch.depth - place.depth) >= min_delta);
 }
 
-level_id generic_shaft_dest(level_pos lpos)
+level_id generic_shaft_dest(level_pos lpos, bool known = false)
 {
-    level_id  lid = lpos.id;
-    coord_def pos = lpos.pos;
+    level_id  lid   = lpos.id;
+    coord_def pos   = lpos.pos;
 
     if (lid.level_type != LEVEL_DUNGEON)
         return lid;
@@ -1352,14 +1326,26 @@ level_id generic_shaft_dest(level_pos lpos)
     int      curr_depth = lid.depth;
     Branch   &branch    = branches[lid.branch];
 
-    // 25% drop one level
-    // 50% drop two levels
-    // 25% drop three levels
-    lid.depth += 2;
-    if (pos.x % 2)
-        lid.depth--;
-    if (pos.y % 2)
-        lid.depth++;
+    // Shaft traps' behavior depends on whether it is entered intentionally.
+    // Knowingly entering one is more likely to drop you 1 level.
+    // Falling in unknowingly can drop you 1/2/3 levels with equal chance.
+
+    if (known)
+    {
+        // Chances are 5/8s for 1 level, 2/8s for 2 levels, 1/8 for 3 levels
+        int s = random2(8) + 1;
+        if (s == 1)
+            lid.depth += 3;
+        else if (s <= 3)
+            lid.depth += 2;
+        else
+            lid.depth += 1;
+    }
+    else
+    {
+        // 33.3% for 1, 2, 3
+        lid.depth += 1 + random2(3);
+    }
 
     if (lid.depth > branch.depth)
         lid.depth = branch.depth;
@@ -1382,7 +1368,7 @@ level_id generic_shaft_dest(level_pos lpos)
     return lid;
 }
 
-level_id generic_shaft_dest(coord_def pos)
+level_id generic_shaft_dest(coord_def pos, bool known = false)
 {
     return generic_shaft_dest(level_pos(level_id::current(), pos));
 }
@@ -1392,7 +1378,7 @@ void handle_items_on_shaft(const coord_def& pos, bool open_shaft)
     if (!is_valid_shaft_level())
         return;
 
-    level_id  dest = generic_shaft_dest(pos);
+    level_id dest = generic_shaft_dest(pos);
 
     if (dest == level_id::current())
         return;
diff --git a/crawl-ref/source/traps.h b/crawl-ref/source/traps.h
index bd25c0c9a8..1fe167040f 100644
--- a/crawl-ref/source/traps.h
+++ b/crawl-ref/source/traps.h
@@ -33,7 +33,7 @@ trap_def* find_trap(const coord_def& where);
 trap_type get_trap_type(const coord_def& where);
 
 bool     is_valid_shaft_level(const level_id &place = level_id::current());
-level_id generic_shaft_dest(coord_def pos);
+level_id generic_shaft_dest(coord_def pos, bool known);
 void     handle_items_on_shaft(const coord_def& where, bool open_shaft);
 
 int       num_traps_for_place(int level_number = -1,