feat: Weapons track what is killed with them (#5394)

* make kill_tracker usable without the event bus

* pass the weapon through the attack function chain and record if it kills something

* record murder weapon

* override to disable stats for kills xp in kill_tracker

* Fixed pointers, it actually works now. Hacked in a crude count display in the item description.

* de/serialize item kill tracker

* First pass for a proper UI

* track NPC kills

* astyle, draw borders

* record kills for thrown items

* item::kill_count()

* style(autofix.ci): automated formatting

* prevent kills from being tracked if ENABLE_EVENTS is toggled off

* remove kills_set() since it isn't actually needed for anything

* explicit overloads for character::deal damage(), remove some commented out code that never worked

* renamed every instance of "s_weapon" and "s_proj"

* rename one last instance of s_weapon to source_weapon

---------

Co-authored-by: autofix-ci[bot] <114827586+autofix-ci[bot]@users.noreply.github.com>

data/raw/keybindings/keybindings.json

@@ -3268,6 +3268,13 @@
     "name": "Disassemble",
     "bindings": [ { "input_method": "keyboard", "key": "D" } ]
   },
+  {
+    "id": "SHOW_KILL_LIST",
+    "type": "keybinding",
+    "category": "INVENTORY_ITEM",
+    "name": "Kills",
+    "bindings": [ { "input_method": "keyboard", "key": "K" } ]
+  },
   {
     "id": "FAVORITE_ADD",
     "type": "keybinding",

src/ballistics.cpp

@@ -201,7 +201,7 @@ projectile_attack_aim projectile_attack_roll( const dispersion_sources &dispersi
 
 dealt_projectile_attack projectile_attack( const projectile &proj_arg, const tripoint &source,
         const tripoint &target_arg, const dispersion_sources &dispersion,
-        Creature *origin, const vehicle *in_veh )
+        Creature *origin, item *source_weapon, const vehicle *in_veh )
 {
     const bool do_animation = get_option<bool>( "ANIMATION_PROJECTILES" );
 
@@ -432,7 +432,7 @@ dealt_projectile_attack projectile_attack( const projectile &proj_arg, const tri
                 continue;
             }
             attack.missed_by = cur_missed_by;
-            critter->deal_projectile_attack( null_source ? nullptr : origin, attack );
+            critter->deal_projectile_attack( null_source ? nullptr : origin, source_weapon, attack );
             // Critter can still dodge the projectile
             // In this case hit_critter won't be set
             if( attack.hit_critter != nullptr ) {
@@ -501,7 +501,7 @@ dealt_projectile_attack projectile_attack( const projectile &proj_arg, const tri
             Creature &z = *mon_ptr;
             add_msg( _( "The attack bounced to %s!" ), z.get_name() );
             z.add_effect( effect_bounced, 1_turns );
-            projectile_attack( proj, tp, z.pos(), dispersion, origin, in_veh );
+            projectile_attack( proj, tp, z.pos(), dispersion, origin, source_weapon, in_veh );
             sfx::play_variant_sound( "fire_gun", "bio_lightning_tail",
                                      sfx::get_heard_volume( z.pos() ), sfx::get_heard_angle( z.pos() ) );
         }

src/ballistics.h

@@ -3,6 +3,7 @@
 #define CATA_SRC_BALLISTICS_H
 
 class Creature;
+class item;
 class dispersion_sources;
 class vehicle;
 struct dealt_projectile_attack;
@@ -32,7 +33,7 @@ projectile_attack_aim projectile_attack_roll( const dispersion_sources &dispersi
  */
 dealt_projectile_attack projectile_attack( const projectile &proj_arg, const tripoint &source,
         const tripoint &target_arg, const dispersion_sources &dispersion,
-        Creature *origin = nullptr, const vehicle *in_veh = nullptr );
+        Creature *origin = nullptr, item *source_weapon = nullptr, const vehicle *in_veh = nullptr );
 
 namespace ranged
 {

src/character.cpp

@@ -8917,7 +8917,9 @@ void Character::on_hit( Creature *source, bodypart_id bp_hit,
     Where damage to character is actually applied to hit body parts
     Might be where to put bleed stuff rather than in player::deal_damage()
  */
-void Character::apply_damage( Creature *source, bodypart_id hurt, int dam,
+void Character::apply_damage( Creature *source, item *source_weapon, item *source_projectile,
+                              bodypart_id hurt,
+                              int dam,
                               const bool bypass_med )
 {
     if( is_dead_state() || has_trait( trait_DEBUG_NODMG ) ) {
@@ -8959,6 +8961,12 @@ void Character::apply_damage( Creature *source, bodypart_id hurt, int dam,
                     get_name() );
         }
         set_killer( source );
+        if( source_weapon ) {
+            source_weapon->add_npc_kill( get_name() );
+        }
+        if( source_projectile ) {
+            source_projectile->add_npc_kill( get_name() );
+        }
     }
 
     if( !bypass_med ) {
@@ -8972,9 +8980,21 @@ void Character::apply_damage( Creature *source, bodypart_id hurt, int dam,
         }
     }
 }
+void Character::apply_damage( Creature *source, item *source_weapon, bodypart_id hurt,
+                              int dam,
+                              const bool bypass_med )
+{
+    apply_damage( source, source_weapon, nullptr, hurt, dam, bypass_med );
+}
+void Character::apply_damage( Creature *source, bodypart_id hurt,
+                              int dam,
+                              const bool bypass_med )
+{
+    apply_damage( source, nullptr, nullptr, hurt, dam, bypass_med );
+}
 
 dealt_damage_instance Character::deal_damage( Creature *source, bodypart_id bp,
-        const damage_instance &d )
+        const damage_instance &d, item *source_weapon, item *source_projectile )
 {
     if( has_trait( trait_DEBUG_NODMG ) ) {
         return dealt_damage_instance();
@@ -8987,7 +9007,8 @@ dealt_damage_instance Character::deal_damage( Creature *source, bodypart_id bp,
     }
 
     //damage applied here
-    dealt_damage_instance dealt_dams = Creature::deal_damage( source, bp, d );
+    dealt_damage_instance dealt_dams = Creature::deal_damage( source, bp, d, source_weapon,
+                                       source_projectile );
     //block reduction should be by applied this point
     int dam = dealt_dams.total_damage();
 
@@ -9128,6 +9149,16 @@ dealt_damage_instance Character::deal_damage( Creature *source, bodypart_id bp,
     on_hurt( source );
     return dealt_dams;
 }
+dealt_damage_instance Character::deal_damage( Creature *source, bodypart_id bp,
+        const damage_instance &d, item *source_weapon )
+{
+    return deal_damage( source, bp, d, source_weapon, nullptr );
+}
+dealt_damage_instance Character::deal_damage( Creature *source, bodypart_id bp,
+        const damage_instance &d )
+{
+    return deal_damage( source, bp, d, nullptr, nullptr );
+}
 
 int Character::reduce_healing_effect( const efftype_id &eff_id, int remove_med,
                                       const bodypart_id &hurt )

src/character.h

@@ -671,9 +671,18 @@ class Character : public Creature, public location_visitable<Character>
         void did_hit( Creature &target );
 
         /** Actually hurt the player, hurts a body_part directly, no armor reduction */
+        void apply_damage( Creature *source, item *source_weapon, item *source_projectile, bodypart_id hurt,
+                           int dam,
+                           bool bypass_med = false ) override;
+        void apply_damage( Creature *source, item *source_weapon, bodypart_id hurt, int dam,
+                           bool bypass_med = false ) override;
         void apply_damage( Creature *source, bodypart_id hurt, int dam,
                            bool bypass_med = false ) override;
         /** Calls Creature::deal_damage and handles damaged effects (waking up, etc.) */
+        dealt_damage_instance deal_damage( Creature *source, bodypart_id bp,
+                                           const damage_instance &d, item *source_weapon, item *source_projectile ) override;
+        dealt_damage_instance deal_damage( Creature *source, bodypart_id bp,
+                                           const damage_instance &d, item *source_weapon ) override;
         dealt_damage_instance deal_damage( Creature *source, bodypart_id bp,
                                            const damage_instance &d ) override;
         /** Reduce healing effect intensity, return initial intensity of the effect */

src/creature.cpp

@@ -578,7 +578,8 @@ int Creature::deal_melee_attack( Creature *source, int hitroll )
     return hit_spread;
 }
 
-void Creature::deal_melee_hit( Creature *source, int hit_spread, bool critical_hit,
+void Creature::deal_melee_hit( Creature *source, item *source_weapon, int hit_spread,
+                               bool critical_hit,
                                const damage_instance &dam, dealt_damage_instance &dealt_dam )
 {
     if( source == nullptr || source->is_hallucination() ) {
@@ -592,7 +593,8 @@ void Creature::deal_melee_hit( Creature *source, int hit_spread, bool critical_h
         if( mons && mons->mounted_player ) {
             if( !mons->has_flag( MF_MECH_DEFENSIVE ) &&
                 one_in( std::max( 2, mons->get_size() - mons->mounted_player->get_size() ) ) ) {
-                mons->mounted_player->deal_melee_hit( source, hit_spread, critical_hit, dam, dealt_dam );
+                mons->mounted_player->deal_melee_hit( source, source_weapon, hit_spread, critical_hit, dam,
+                                                      dealt_dam );
                 return;
             }
         }
@@ -603,9 +605,14 @@ void Creature::deal_melee_hit( Creature *source, int hit_spread, bool critical_h
     block_hit( source, bp_hit, d );
 
     on_hit( source, bp_hit ); // trigger on-gethit events
-    dealt_dam = deal_damage( source, bp_hit, d );
+    dealt_dam = deal_damage( source, bp_hit, d, source_weapon );
     dealt_dam.bp_hit = bp_token;
 }
+void Creature::deal_melee_hit( Creature *source, int hit_spread, bool critical_hit,
+                               const damage_instance &dam, dealt_damage_instance &dealt_dam )
+{
+    deal_melee_hit( source, nullptr, hit_spread, critical_hit, dam, dealt_dam );
+}
 
 namespace ranged
 {
@@ -708,10 +715,12 @@ auto get_stun_srength( const projectile &proj, creature_size size ) -> int
  * Attempts to harm a creature with a projectile.
  *
  * @param source Pointer to the creature who shot the projectile.
+ * @param source_weapon Pointer to the weapon used to fire the projectile.
  * @param attack A structure describing the attack and its results.
  * @param print_messages enables message printing by default.
  */
-void Creature::deal_projectile_attack( Creature *source, dealt_projectile_attack &attack )
+void Creature::deal_projectile_attack( Creature *source, item *source_weapon,
+                                       dealt_projectile_attack &attack )
 {
     const bool magic = attack.proj.has_effect( ammo_effect_magic );
     const bool targetted_crit_allowed = !attack.proj.has_effect( ammo_effect_NO_CRIT );
@@ -726,7 +735,7 @@ void Creature::deal_projectile_attack( Creature *source, dealt_projectile_attack
         if( mons && mons->mounted_player ) {
             if( !mons->has_flag( MF_MECH_DEFENSIVE ) &&
                 one_in( std::max( 2, mons->get_size() - mons->mounted_player->get_size() ) ) ) {
-                mons->mounted_player->deal_projectile_attack( source, attack );
+                mons->mounted_player->deal_projectile_attack( source, source_weapon, attack );
                 return;
             }
         }
@@ -844,7 +853,8 @@ void Creature::deal_projectile_attack( Creature *source, dealt_projectile_attack
 
     // If we have a shield, it might passively block ranged impacts
     block_ranged_hit( source, bp_hit, impact );
-    dealt_dam = deal_damage( source, bp_hit, impact );
+    // If the projectile survives, both it and the launcher get credit for the kill.
+    dealt_dam = deal_damage( source, bp_hit, impact, source_weapon, attack.proj.get_drop() );
     dealt_dam.bp_hit = bp_hit->token;
 
     // Apply ammo effects to target.
@@ -926,8 +936,13 @@ void Creature::deal_projectile_attack( Creature *source, dealt_projectile_attack
     attack.missed_by = goodhit;
 }
 
+void Creature::deal_projectile_attack( Creature *source, dealt_projectile_attack &attack )
+{
+    deal_projectile_attack( source, nullptr, attack );
+}
+
 dealt_damage_instance Creature::deal_damage( Creature *source, bodypart_id bp,
-        const damage_instance &dam )
+        const damage_instance &dam, item *source_weapon, item *source_projectile )
 {
     if( is_dead_state() ) {
         return dealt_damage_instance();
@@ -951,9 +966,19 @@ dealt_damage_instance Creature::deal_damage( Creature *source, bodypart_id bp,
 
     mod_pain( total_pain );
 
-    apply_damage( source, bp, total_damage );
+    apply_damage( source, source_weapon, source_projectile, bp, total_damage );
     return dealt_dams;
 }
+dealt_damage_instance Creature::deal_damage( Creature *source, bodypart_id bp,
+        const damage_instance &dam, item *source_weapon )
+{
+    return deal_damage( source, bp, dam, source_weapon, nullptr );
+}
+dealt_damage_instance Creature::deal_damage( Creature *source, bodypart_id bp,
+        const damage_instance &dam )
+{
+    return deal_damage( source, bp, dam, nullptr, nullptr );
+}
 void Creature::deal_damage_handle_type( const damage_unit &du, bodypart_id bp, int &damage,
                                         int &pain )
 {

src/creature.h

@@ -356,11 +356,16 @@ class Creature
 
         // completes a melee attack against the creature
         // dealt_dam is overwritten with the values of the damage dealt
+        virtual void deal_melee_hit( Creature *source, item *source_weapon, int hit_spread,
+                                     bool critical_hit,
+                                     const damage_instance &dam, dealt_damage_instance &dealt_dam );
         virtual void deal_melee_hit( Creature *source, int hit_spread, bool critical_hit,
                                      const damage_instance &dam, dealt_damage_instance &dealt_dam );
 
         // Makes a ranged projectile attack against the creature
         // Sets relevant values in `attack`.
+        virtual void deal_projectile_attack( Creature *source, item *source_weapon,
+                                             dealt_projectile_attack &attack );
         virtual void deal_projectile_attack( Creature *source, dealt_projectile_attack &attack );
 
         /**
@@ -374,15 +379,28 @@ class Creature
          * @param source The attacking creature, can be null.
          * @param bp The attacked body part
          * @param dam The damage dealt
+         * @param source_weapon The weapon used in the attack, optional
+         * @param source_projectile The projectile fired in the attack, optional
          */
+        virtual dealt_damage_instance deal_damage( Creature *source, bodypart_id bp,
+                const damage_instance &dam, item *source_weapon, item *source_projectile );
+        virtual dealt_damage_instance deal_damage( Creature *source, bodypart_id bp,
+                const damage_instance &dam, item *source_weapon );
         virtual dealt_damage_instance deal_damage( Creature *source, bodypart_id bp,
                 const damage_instance &dam );
+
         // for each damage type, how much gets through and how much pain do we
         // accrue? mutates damage and pain
         virtual void deal_damage_handle_type( const damage_unit &du,
                                               bodypart_id bp, int &damage, int &pain );
         // directly decrements the damage. ONLY handles damage, doesn't
         // increase pain, apply effects, etc
+        virtual void apply_damage( Creature *source, item *source_weapon, item *source_projectile,
+                                   bodypart_id bp,
+                                   int amount,
+                                   bool bypass_med = false ) = 0;
+        virtual void apply_damage( Creature *source, item *source_weapon, bodypart_id bp, int amount,
+                                   bool bypass_med = false ) = 0;
         virtual void apply_damage( Creature *source, bodypart_id bp, int amount,
                                    bool bypass_med = false ) = 0;
 

src/examine_item_menu.cpp

@@ -190,6 +190,13 @@ bool run(
         return true;
     } );
 
+    if( itm.kill_count() > 0 ) {
+        add_entry( "SHOW_KILL_LIST", hint_rating::good, [&]() {
+            itm.show_kill_list();
+            return true;
+        } );
+    }
+
     if( !itm.is_favorite ) {
         add_entry( "FAVORITE_ADD",
         hint_rating::good, [&]() {

src/item.cpp

@@ -93,6 +93,7 @@
 #include "ret_val.h"
 #include "rot.h"
 #include "rng.h"
+#include "scores_ui.h"
 #include "skill.h"
 #include "stomach.h"
 #include "string_formatter.h"
@@ -10715,3 +10716,43 @@ location_vector<item> &item::get_components()
 {
     return components;
 }
+
+bool item::init_kill_tracker()
+{
+    if( kills ) {
+        return true;
+    } else if( get_option<bool>( "ENABLE_EVENTS" ) ) {
+        kills = std::make_unique<kill_tracker>( false );
+        return true;
+    } else {
+        return false;
+    }
+}
+void item::add_monster_kill( mtype_id mon )
+{
+    if( init_kill_tracker() ) {
+        kills->add_monster( mon );
+    }
+}
+void item::add_npc_kill( std::string npc )
+{
+    if( init_kill_tracker() ) {
+        kills->add_npc( npc );
+    }
+}
+void item::show_kill_list()
+{
+    if( !kills ) {
+        debugmsg( "Tried to display empty kill list" );
+        return;
+    }
+    show_kills( *kills );
+}
+int item::kill_count()
+{
+    if( !kills ) {
+        return 0;
+    } else {
+        return kills->monster_kill_count() + kills->npc_kill_count();
+    }
+}

src/item.h

@@ -23,6 +23,7 @@
 #include "gun_mode.h"
 #include "io_tags.h"
 #include "item_contents.h"
+#include "kill_tracker.h"
 #include "location_vector.h"
 #include "pimpl.h"
 #include "safe_reference.h"
@@ -2425,6 +2426,23 @@ class item : public location_visitable<item>, public game_object<item>
          * Ideally, this would be stored outside item class.
          */
         pimpl<item_drop_token> drop_token;
+
+    private:
+        /** Kill tracker */
+        std::unique_ptr<kill_tracker> kills;
+        /**
+         * Check if there's a kill_tracker
+         * Make one if there isn't and if ENABLE_EVENTS option is toggled on
+         * @returns true if a kill_tracker exists, or if one was created
+         *          false if there is no kill_tracker, and one wasn't created
+         */
+        bool init_kill_tracker();
+
+    public:
+        void add_monster_kill( mtype_id );
+        void add_npc_kill( std::string );
+        void show_kill_list();
+        int kill_count();
 };
 
 bool item_compare_by_charges( const item &left, const item &right );