feat(balance): Use rigid storage first when calculating non-rigid encumbrance (#9692)

* Use rigid storage first when calculating non-rigid encumbrance

* Fixes for non-rigid storage

Author: Kelenius

src/character.cpp

@@ -2902,11 +2902,6 @@ void Character::inv_set_stack_favorite( int position, bool favorite )
     inv.set_stack_favorite( position, favorite );
 }
 
-units::volume Character::inv_volume() const
-{
-    return inv.volume();
-}
-
 void Character::inv_unsort()
 {
     inv.unsort();

src/character.h

@@ -1293,8 +1293,6 @@ class Character : public Creature, public location_visitable<Character>
 
         detached_ptr<item> inv_remove_item( item * );
 
-        units::volume inv_volume() const;
-
         void inv_unsort();
 
         void inv_clear();

src/item.cpp

@@ -4199,22 +4199,10 @@ void item::final_info( std::vector<iteminfo> &info, const iteminfo_query &parts_
     }
 
     if( parts->test( iteminfo_parts::BASE_RIGIDITY ) ) {
-        if( const islot_armor *armor = find_armor_data() ) {
-            if( !type->rigid ) {
-                info.emplace_back( "BASE",
-                                   _( "* This item is <info>not rigid</info>.  Its"
-                                      " volume and encumbrance increase with contents." ) );
-            } else {
-                bool any_encumb_increase = std::ranges::any_of( armor->data,
-                []( armor_portion_data data ) {
-                    return data.encumber != data.max_encumber;
-                } );
-                if( any_encumb_increase ) {
-                    info.emplace_back( "BASE",
-                                       _( "* This item is <info>not rigid</info>.  Its"
-                                          " volume and encumbrance increase with contents." ) );
-                }
-            }
+        if( is_non_rigid() ) {
+            info.emplace_back( "BASE",
+                               _( "* This item is <info>not rigid</info>.  Its"
+                                  " volume and encumbrance increase with contents." ) );
         }
     }
 
@@ -6138,6 +6126,21 @@ bool item::can_shatter() const
     return only_made_of( is_glass ) || has_flag( flag_SHATTERS );
 }
 
+bool item::is_non_rigid() const
+{
+    if( const islot_armor *armor = find_armor_data() ) {
+        if( !type->rigid ) {
+            return true;
+        }
+        bool any_encumb_increase = std::ranges::any_of( armor->data,
+        []( armor_portion_data data ) {
+            return data.encumber != data.max_encumber;
+        } );
+        return any_encumb_increase;
+    }
+    return false;
+}
+
 void item::unset_flags()
 {
     const bool affects_processing = item_tags.count( flag_RADIO_ACTIVATION ) ||
@@ -6741,24 +6744,29 @@ int item::get_encumber( const Character &who, const bodypart_id &bodypart ) cons
 
     contents_volume += contents.item_size_modifier();
 
-    if( who.is_worn( *this ) ) {
+    if( who.is_worn( *this ) && this->is_non_rigid() ) {
         const islot_armor *armor = find_armor_data();
 
         if( armor != nullptr ) {
             for( const armor_portion_data &entry : armor->data ) {
-                if( entry.covers.test( bodypart.id() ) ) {
-                    if( entry.max_encumber != 0 ) {
-                        units::volume char_storage( 0_ml );
-
-                        for( const item * const &e : who.worn ) {
-                            char_storage += e->get_storage();
+                if( entry.max_encumber != 0 && entry.covers.test( bodypart.id() ) ) {
+                    units::volume rigid_storage( 0_ml );
+                    units::volume non_rigid_storage( 0_ml );
+                    const units::volume volume_carried = who.volume_carried();
+
+                    for( const item * const &e : who.worn ) {
+                        if( e->is_non_rigid() ) {
+                            non_rigid_storage += e->get_storage();
+                        } else {
+                            rigid_storage += e->get_storage();
                         }
+                    }
 
-                        if( char_storage != 0_ml ) {
-                            // Cast up to 64 to prevent overflow. Dividing before would prevent this but lose data.
-                            contents_volume += units::from_milliliter( static_cast<int64_t>( armor->storage.value() ) *
-                                               who.inv_volume().value() / char_storage.value() );
-                        }
+                    if( volume_carried > rigid_storage && non_rigid_storage > 0_ml ) {
+                        // Cast up to 64 to prevent overflow. Dividing before would prevent this but lose data.
+                        contents_volume += units::from_milliliter( static_cast<int64_t>( armor->storage.value() ) *
+                                           ( static_cast<int64_t>( volume_carried.value() ) - rigid_storage.value() ) /
+                                           non_rigid_storage.value() );
                     }
                 }
             }
@@ -6783,11 +6791,7 @@ int item::get_encumber_when_containing(
         if( entry.covers.test( bodypart.id() ) ) {
             encumber = entry.encumber;
             // Non-rigid items add additional encumbrance proportional to their volume
-            bool any_encumb_increase = std::ranges::any_of( armor->data,
-            []( armor_portion_data data ) {
-                return data.encumber != data.max_encumber;
-            } );
-            if( !type->rigid || any_encumb_increase ) {
+            if( this->is_non_rigid() ) {
                 const int capacity = get_total_capacity().value();
                 if( entry.max_encumber == 0 ) {
                     encumber += contents_volume / 500_ml;

src/item.h

@@ -1728,6 +1728,9 @@ class item : public location_visitable<item>, public game_object<item>
         /**If item made out of glass, or has the SHATTERS flag?*/
         bool can_shatter() const;
 
+        /** If the item is non-rigid: either has rigid = false or max_encumber higher than encumber */
+        bool is_non_rigid() const;
+
         /**
          * @name Item properties
          *