Add u_var "bmi_permil" (BMI * 1000)

Co-authored by @dseguin

Author: wapcaplet

doc/NPCs.md

@@ -964,6 +964,7 @@ Example | Description
 `"u_val": "friendly"` | Current friendly level, only works for monsters.
 `"u_val": "vitamin"` | Current vitamin level. `name` must also be specified which is the vitamins id.
 `"u_val": "age"` | Current age in years.
+`"u_val": "bmi_permil"` | Current BMI per mille (Body Mass Index x 1000)
 `"u_val": "height"` | Current height in cm. When setting there is a range for your character size category. Setting it too high or low will use the limit instead. For tiny its 58, and 87. For small its 88 and 144. For medium its 145 and 200. For large its 201 and 250. For huge its 251 and 320.
 `"distance": []` | Distance between two targets. Valid targets are: "u","npc" and an object with a variable name.
 `"hour"` | Hours since midnight.

src/character.h

@@ -501,6 +501,7 @@ class Character : public Creature, public visitable
         /** Getter for need values exclusive to characters */
         int get_stored_kcal() const;
         int get_healthy_kcal() const;
+        // Returns stored kcals as a proportion of "healthy" kcals (1.0 == healthy)
         float get_kcal_percent() const;
         int kcal_speed_penalty() const;
         int get_hunger() const;

src/condition.cpp

@@ -1384,6 +1384,10 @@ std::function<int( const T & )> conditional_t<T>::get_get_int( const JsonObject
             return [is_npc]( const T & d ) {
                 return d.actor( is_npc )->get_height();
             };
+        } else if( checked_value == "bmi_permil" ) {
+            return [is_npc]( const T & d ) {
+                return d.actor( is_npc )->get_bmi_permil();
+            };
         }
     } else if( jo.has_member( "moon" ) ) {
         return []( const T & ) {

src/talker.h

@@ -483,5 +483,8 @@ class talker
         virtual int get_height() const {
             return 0;
         }
+        virtual int get_bmi_permil() const {
+            return 0;
+        }
 };
 #endif // CATA_SRC_TALKER_H

src/talker_character.cpp

@@ -564,6 +564,11 @@ int talker_character_const::get_age() const
     return me_chr_const->age();
 }
 
+int talker_character_const::get_bmi_permil() const
+{
+    return std::round( me_chr_const->get_bmi() * 1000.0f );
+}
+
 void talker_character::set_height( int amount )
 {
     me_chr->set_base_height( amount );

src/talker_character.h

@@ -117,6 +117,7 @@ class talker_character_const: public talker
         int get_kill_xp() const override;
         int get_age() const override;
         int get_height() const override;
+        int get_bmi_permil() const override;
     protected:
         talker_character_const() = default;
         const Character *me_chr_const;