(Comments Requested) Monster Invulnerability JSON field

src/monstergenerator.cpp

@@ -743,6 +743,19 @@
     }
 }
 
+void monster_invulnerability::deserialize( const JsonObject &jo )
+{
+    optional( jo, false, "damage_type", damage_type, damage_type_id( "all" ) );
+    optional( jo, false, "material", material, material_id::NULL_ID() );
+    optional( jo, false, "amount", amount, 0 );
+}
+
+void monster_vulnerability::deserialize( const JsonObject &jo )
+{
+    optional( jo, false, "material", material, material_id::NULL_ID() );
+    optional( jo, false, "flag", flag, flag_id::NULL_ID() );
+}
+
 void mtype::load( const JsonObject &jo, const std::string &src )
 {
     bool strict = src == "dda";
@@ -784,6 +797,9 @@
     if( was_loaded && jo.has_member( "copy-from" ) && looks_like.empty() ) {
         looks_like = jo.get_string( "copy-from" );
     }
+    optional( jo, was_loaded, "invulnerability", invulnerabilities );
+    optional( jo, was_loaded, "vulnerability", vulnerability );
+
     jo.read( "looks_like", looks_like );
 
     assign( jo, "bodytype", bodytype );

src/mtype.h

@@ -236,6 +236,22 @@ struct mon_effect_data {
     void load( const JsonObject &jo );
 };
 
+struct monster_invulnerability {
+    damage_type_id damage_type;    // e.g. "bash", "cut", "all"
+    material_id material;          // optional; can be empty
+    int amount = 0;                // e.g. percent or flat reduction
+
+    void deserialize( const JsonObject &jo );
+};
+
+struct monster_vulnerability {
+    material_id material;          // optional; items of this material ignore invulnerability
+    flag_id flag;                  // optional; items of with this flag ignore invulnerability
+
+    void deserialize( const JsonObject &jo );
+};
+
+
 /** Pet food data */
 struct pet_food_data {
     std::set<std::string> food;
@@ -346,6 +362,8 @@ struct mtype {
         mtype_id burn_into;
 
         std::vector<revive_type> revive_types;
+        std::vector<monster_invulnerability> invulnerabilities;
+        std::optional<monster_vulnerability> vulnerability;
 
         mtype_id zombify_into; // mtype_id this monster zombifies into
         mtype_id fungalize_into; // mtype_id this monster fungalize into