Add support for specify monster armor coverage

data/json/monsters/misc.json

@@ -13,6 +13,9 @@
     "material": [ "flesh" ],
     "symbol": "X",
     "color": "white",
+    "armor_coverage": 50,
+    "armor_bullet": 100,
+    "unarmored_bullet": 10,
     "aggression": 100,
     "morale": 100,
     "melee_cut": 0,

src/damage.cpp

@@ -235,12 +235,20 @@ resistances::resistances( const item &armor, bool to_self )
         }
     }
 }
-resistances::resistances( monster &monster ) : resistances()
+resistances::resistances( monster &monster, bool unarmored ) : resistances()
 {
-    set_resist( damage_type::BASH, monster.type->armor_bash );
-    set_resist( damage_type::CUT,  monster.type->armor_cut );
-    set_resist( damage_type::STAB, monster.type->armor_stab );
-    set_resist( damage_type::BULLET, monster.type->armor_bullet );
+    if( unarmored ) {
+        set_resist( damage_type::BASH, monster.type->unarmored_bash );
+        set_resist( damage_type::CUT,  monster.type->unarmored_cut );
+        set_resist( damage_type::STAB, monster.type->unarmored_stab );
+        set_resist( damage_type::BULLET, monster.type->unarmored_bullet );
+    } else {
+        set_resist( damage_type::BASH, monster.type->armor_bash );
+        set_resist( damage_type::CUT,  monster.type->armor_cut );
+        set_resist( damage_type::STAB, monster.type->armor_stab );
+        set_resist( damage_type::BULLET, monster.type->armor_bullet );
+    }
+    // Acid and fire have 100% coverage
     set_resist( damage_type::ACID, monster.type->armor_acid );
     set_resist( damage_type::HEAT, monster.type->armor_fire );
 }

src/damage.h

@@ -125,7 +125,7 @@ struct resistances {
 
     // If to_self is true, we want armor's own resistance, not one it provides to wearer
     explicit resistances( const item &armor, bool to_self = false );
-    explicit resistances( monster &monster );
+    explicit resistances( monster &monster, bool unarmored = false );
     void set_resist( damage_type dt, float amount );
     float type_resist( damage_type dt ) const;
 

src/monster.cpp

@@ -1492,7 +1492,8 @@ void monster::absorb_hit( const bodypart_id &, damage_instance &dam )
     for( auto &elem : dam.damage_units ) {
         add_msg_debug( debugmode::DF_MONSTER, "Dam Type: %s :: Ar Pen: %.1f :: Armor Mult: %.1f",
                        name_by_dt( elem.type ), elem.res_pen, elem.res_mult );
-        elem.amount -= std::min( resistances( *this ).get_effective_resist( elem ) +
+        bool unarmored = rng( 1, 100 ) > this->type->armor_coverage;
+        elem.amount -= std::min( resistances( *this, unarmored ).get_effective_resist( elem ) +
                                  get_worn_armor_val( elem.type ), elem.amount );
     }
 }

src/monstergenerator.cpp

@@ -434,6 +434,19 @@ void MonsterGenerator::finalize_mtypes()
             mon.armor_fire = 0;
         }
 
+        if( mon.unarmored_bash < 0 ) {
+            mon.unarmored_bash = 0;
+        }
+        if( mon.unarmored_cut < 0 ) {
+            mon.unarmored_cut = 0;
+        }
+        if( mon.unarmored_stab < 0 ) {
+            mon.unarmored_stab = mon.unarmored_cut * 0.8;
+        }
+        if( mon.unarmored_bullet < 0 ) {
+            mon.unarmored_bullet = 0;
+        }
+
         // Lower bound for hp scaling
         mon.hp = std::max( mon.hp, 1 );
 
@@ -710,13 +723,19 @@ void mtype::load( const JsonObject &jo, const std::string &src )
     assign( jo, "grab_strength", grab_strength, strict, 0 );
 
     assign( jo, "dodge", sk_dodge, strict, 0 );
+    assign( jo, "armor_coverage", armor_coverage, strict, 0, 100 );
     assign( jo, "armor_bash", armor_bash, strict, 0 );
     assign( jo, "armor_cut", armor_cut, strict, 0 );
     assign( jo, "armor_bullet", armor_bullet, strict, 0 );
     assign( jo, "armor_stab", armor_stab, strict, 0 );
     assign( jo, "armor_acid", armor_acid, strict, 0 );
     assign( jo, "armor_fire", armor_fire, strict, 0 );
 
+    assign( jo, "unarmored_bash", unarmored_bash, strict, 0 );
+    assign( jo, "unarmored_cut", unarmored_cut, strict, 0 );
+    assign( jo, "unarmored_bullet", unarmored_bullet, strict, 0 );
+    assign( jo, "unarmored_stab", unarmored_stab, strict, 0 );
+
     optional( jo, was_loaded, "bleed_rate", bleed_rate, 100 );
 
     assign( jo, "vision_day", vision_day, strict, 0 );

src/mtype.h

@@ -321,12 +321,18 @@ struct mtype {
         int sk_dodge = 0;       /** dodge skill */
 
         /** If unset (-1) then values are calculated automatically from other properties */
-        int armor_bash = -1;    /** innate armor vs. bash */
-        int armor_cut  = -1;    /** innate armor vs. cut */
-        int armor_stab = -1;    /** innate armor vs. stabbing */
-        int armor_bullet = -1;  /** innate armor vs. bullet */
-        int armor_acid = -1;    /** innate armor vs. acid */
-        int armor_fire = -1;    /** innate armor vs. fire */
+        int armor_coverage = 100;   /** percent of the monster covered by armor */
+        int armor_bash = -1;        /** innate armor vs. bash */
+        int armor_cut  = -1;        /** innate armor vs. cut */
+        int armor_stab = -1;        /** innate armor vs. stabbing */
+        int armor_bullet = -1;      /** innate armor vs. bullet */
+        int armor_acid = -1;        /** innate armor vs. acid */
+        int armor_fire = -1;        /** innate armor vs. fire */
+
+        int unarmored_bash = -1;    /** unarmored resistance vs. bash */
+        int unarmored_cut  = -1;    /** unarmored resistance vs. cut */
+        int unarmored_stab = -1;    /** unarmored resistance vs. stabbing */
+        int unarmored_bullet = -1;  /** unarmored resistance vs. bullet */
 
         // Bleed rate in percent, 0 makes the monster immune to bleeding
         int bleed_rate = 100;