Prevent monsters from leaping to their death in water (#38150)

CleverRaven · Feb 20, 2020 · f3fbeb8 · f3fbeb8
1 parent f5babd6
commit f3fbeb8
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Showing 3 changed files with 28 additions and 19 deletions.
diff --git a/src/mattack_actors.cpp b/src/mattack_actors.cpp
@@ -109,6 +109,10 @@ bool leap_actor::call( monster &z ) const
                 break;
             }
         }
+        // don't leap into water if you could drown (#38038)
+        if( z.is_aquatic_danger( dest ) ) {
+            blocked_path = true;
+        }
         if( blocked_path ) {
             continue;
         }

diff --git a/src/monmove.cpp b/src/monmove.cpp
@@ -546,14 +546,19 @@ static float get_stagger_adjust( const tripoint &source, const tripoint &destina
     return std::max( 0.01f, initial_dist - new_dist );
 }
 
+/**
+ * Returns true if the given square presents a possibility of drowning for the monster: it's deep water, it's liquid,
+ * the monster can drown, and there is no boardable vehicle part present.
+ */
+bool monster::is_aquatic_danger( const tripoint &at_pos )
+{
+    return g->m.has_flag_ter( TFLAG_DEEP_WATER, at_pos ) && g->m.has_flag( flag_LIQUID, at_pos ) &&
+           can_drown() && !g->m.veh_at( at_pos ).part_with_feature( "BOARDABLE", false );
+}
+
 bool monster::die_if_drowning( const tripoint &at_pos, const int chance )
 {
-    if( g->m.has_flag( flag_LIQUID, at_pos ) && can_drown() && one_in( chance ) ) {
-        // if there's a vehicle here with a boardable part, the monster is on it
-        // and not drowning
-        if( g->m.veh_at( at_pos ).part_with_feature( "BOARDABLE", false ) ) {
-            return false;
-        }
+    if( is_aquatic_danger( at_pos ) && one_in( chance ) ) {
         die( nullptr );
         if( g->u.sees( at_pos ) ) {
             add_msg( _( "The %s drowns!" ), name() );
@@ -662,11 +667,9 @@ void monster::move()
         }
     }
 
-    // The monster is in a deep water tile and has a chance to drown
-    if( g->m.has_flag_ter( TFLAG_DEEP_WATER, pos() ) ) {
-        if( die_if_drowning( pos(), 10 ) ) {
-            return;
-        }
+    // if the monster is in a deep water tile, it has a chance to drown
+    if( die_if_drowning( pos(), 10 ) ) {
+        return;
     }
 
     if( moves < 0 ) {
@@ -1818,14 +1821,12 @@ void monster::knock_back_to( const tripoint &to )
     }
 
     // If we're still in the function at this point, we're actually moving a tile!
-    if( g->m.has_flag_ter( TFLAG_DEEP_WATER, to ) ) {
-        // die_if_drowning will kill the monster if necessary, but if the deep water
-        // tile is on a vehicle, we should check for swimmers out of water
-        if( !die_if_drowning( to ) && has_flag( MF_AQUATIC ) ) {
-            die( nullptr );
-            if( u_see ) {
-                add_msg( _( "The %s flops around and dies!" ), name() );
-            }
+    // die_if_drowning will kill the monster if necessary, but if the deep water
+    // tile is on a vehicle, we should check for swimmers out of water
+    if( !die_if_drowning( to ) && has_flag( MF_AQUATIC ) ) {
+        die( nullptr );
+        if( u_see ) {
+            add_msg( _( "The %s flops around and dies!" ), name() );
         }
     }
 

diff --git a/src/monster.h b/src/monster.h
@@ -216,6 +216,10 @@ class monster : public Creature
         void footsteps( const tripoint &p ); // noise made by movement
         void shove_vehicle( const tripoint &remote_destination,
                             const tripoint &nearby_destination ); // shove vehicles out of the way
+
+        // check if the given square could drown a drownable monster
+        bool is_aquatic_danger( const tripoint &at_pos );
+
         // check if a monster at a position will drown and kill it if necessary
         // returns true if the monster dies
         // chance is the one_in( chance ) that the monster will drown