feat: implemented item and inventory outline

godot/GameObjects/enemy_unit.tscn

@@ -28,7 +28,7 @@ collision_layer = 6
 collision_mask = 0
 
 [node name="ActorWorldState" type="EnemyWorldState" parent="."]
-editor_available_goals = [ExtResource("1_jwvis"), ExtResource("1_b1qo1")]
+available_goals_inspector = [ExtResource("1_jwvis"), ExtResource("1_b1qo1")]
 unique_name_in_owner = true
 
 [node name="Planner" type="Planner" parent="."]

godot/GameObjects/player_unit.tscn

@@ -33,6 +33,10 @@ unique_name_in_owner = true
 [node name="EntityHealth" type="EntityHealth" parent="."]
 unique_name_in_owner = true
 
+[node name="Inventory" type="Inventory" parent="."]
+weapon = 2
+unique_name_in_owner = true
+
 [node name="NavigationAgent3D" type="NavigationAgent3D" parent="."]
 unique_name_in_owner = true
 path_desired_distance = 0.2

src/enemy_world_state.cpp

@@ -8,10 +8,7 @@
 
 void EnemyWorldState::_bind_methods() {
 #define CLASSNAME EnemyWorldState
-    GDPROPERTY_HINTED(editor_available_goals,
-                      gd::Variant::ARRAY,
-                      gd::PROPERTY_HINT_ARRAY_TYPE,
-                      GDRESOURCETYPE("Goal"));
+    GDPROPERTY_HINTED(available_goals_inspector, gd::Variant::ARRAY, gd::PROPERTY_HINT_ARRAY_TYPE, GDRESOURCETYPE("Goal"));
 }
 
 void EnemyWorldState::_ready() { GDGAMEONLY();
@@ -144,13 +141,13 @@ void EnemyWorldState::try_set_target(Unit *unit) {
         this->parent_unit->set_target_goal(unit, goal);
 }
 
-void EnemyWorldState::set_editor_available_goals(gd::Array array) {
+void EnemyWorldState::set_available_goals_inspector(gd::Array array) {
     this->available_goals.clear();
     for(int i{0}; i < array.size(); ++i)
         this->available_goals.push_back(array[i]);
 }
 
-gd::Array EnemyWorldState::get_editor_available_goals() const {
+gd::Array EnemyWorldState::get_available_goals_inspector() const {
     gd::Array a{};
     for(gd::Ref<goap::Goal> const &goal : this->available_goals)
         a.push_back(goal);

src/enemy_world_state.hpp

@@ -36,8 +36,8 @@ private:
     float calculate_priority(Unit *target);
     gd::Ref<goap::Goal> get_goal_for_target(Unit *unit);
     void try_set_target(Unit *target);
-    void set_editor_available_goals(gd::Array array);
-    gd::Array get_editor_available_goals() const;
+    void set_available_goals_inspector(gd::Array array);
+    gd::Array get_available_goals_inspector() const;
 private:
     gd::Callable aware_unit_death{callable_mp(this, &EnemyWorldState::on_aware_unit_death)};
     gd::Vector<gd::Ref<goap::Goal>> available_goals{};

src/entity_health.cpp

@@ -73,21 +73,33 @@ float EntityHealth::get_wounds_damage_factor() const {
 }
 
 bool EntityHealth::is_conscious() const {
-    return !this->is_dead() && this->wounds_current > 0;
+    return !this->is_dead()
+        && this->wounds_current > 0;
 }
 
 bool EntityHealth::can_be_revived() const {
-    return this->wounds_current <= 0 && this->injury_current > 0;
+    return this->wounds_current <= 0
+        && this->injury_current > 0;
 }
 
 bool EntityHealth::can_be_healed() const {
-    return this->injury_current > 0 && this->wounds_current > 0 && this->wounds_current < this->wounds_max;
+    return this->injury_current > 0
+        && this->wounds_current > 0
+        && this->wounds_current < this->wounds_max;
 }
 
 bool EntityHealth::is_dead() const {
     return this->injury_current <= 0;
 }
 
+void EntityHealth::set_stats(Stats const *stats) {
+    this->stats = stats;
+}
+
+Stats const *EntityHealth::get_stats() const {
+    return this->stats;
+}
+
 void EntityHealth::set_injury_max(int max_health) {
     this->injury_max = max_health;
 }

src/entity_health.hpp

@@ -1,6 +1,7 @@
 #ifndef RTS_ENTITY_HEALTH_HPP
 #define RTS_ENTITY_HEALTH_HPP
 
+#include "stats.hpp"
 #include <godot_cpp/classes/node.hpp>
 
 namespace gd = godot;
@@ -25,6 +26,8 @@ public:
     bool can_be_healed() const;
     bool can_be_damaged() const;
     bool is_dead() const;
+    void set_stats(Stats const *stats);
+    Stats const *get_stats() const;
     void set_injury_max(int max_health);
     int get_injury_max() const;
     int get_injury_current() const;
@@ -32,6 +35,7 @@ public:
     int get_wounds_max() const;
     int get_wounds_current() const;
 private:
+    Stats const *stats;
     // long term health
     int injury_max{10};
     int injury_current{0};

src/inventory.cpp

@@ -0,0 +1,85 @@
+#include "inventory.hpp"
+#include "item_db.hpp"
+#include "unit.hpp"
+#include "utils/godot_macros.hpp"
+
+void Inventory::_bind_methods() {
+#define CLASSNAME Inventory
+    GDPROPERTY_HINTED(weapon_id, gd::Variant::INT, gd::PROPERTY_HINT_ENUM, ItemDB::get_enum_hint());
+    GDPROPERTY_HINTED(armour_id, gd::Variant::INT, gd::PROPERTY_HINT_ENUM, ItemDB::get_enum_hint());
+    GDPROPERTY(inventory_inspector, gd::Variant::DICTIONARY);
+}
+
+void Inventory::_ready() {
+    this->parent_unit = gd::Object::cast_to<Unit>(this->get_parent());
+}
+
+Stats Inventory::get_stats() const {
+    return this->weapon->get_stats() & this->armour->get_stats() & this->helmet->get_stats() & this->utility->get_stats();
+}
+
+void Inventory::add_item(const Item *item, unsigned num) {
+    if(!this->inventory.has(item))
+        this->inventory.insert(item, num);
+    else if(num > 0)
+        this->inventory[item] += num;
+}
+
+unsigned Inventory::get_item_amount(Item const *item) {
+    return this->inventory.has(item) ? this->inventory[item] : 0;
+}
+
+bool Inventory::has_item(Item const *item) {
+    return this->inventory.has(item);
+}
+
+void Inventory::set_weapon(Item const *item) {
+    this->weapon = item != nullptr && item->has_capability(ItemCapability::WeaponEquip) ? item : nullptr;
+}
+
+Item const *Inventory::get_weapon() const {
+    return this->weapon;
+}
+
+void Inventory::set_armour(Item const *item) {
+    this->armour = item != nullptr && item->has_capability(ItemCapability::ArmourEquip) ? item : nullptr;
+}
+
+Item const *Inventory::get_armour() const {
+    return this->armour;
+}
+
+void Inventory::set_weapon_id(int item_id) {
+    this->set_weapon(ItemDB::get_item(item_id));
+}
+
+int Inventory::get_weapon_id() const {
+    return this->weapon ? this->weapon->get_id() : 0;
+}
+
+void Inventory::set_armour_id(int item_id) {
+    this->set_armour(ItemDB::get_item(item_id));
+}
+
+int Inventory::get_armour_id() const {
+    return this->armour ? this->armour->get_id() : 0;
+}
+
+void Inventory::set_inventory_inspector(gd::Dictionary dict) {
+    this->inventory.clear();
+    gd::Array a{dict.keys()};
+    for(int i{0}; i < a.size(); ++i) {
+        gd::StringName const item_name{a[i]};
+        unsigned const amount{dict[item_name]};
+        Item const *item{ItemDB::get_item_by_name(item_name)};
+        if(item != nullptr && amount > 0)
+            this->inventory[item] = amount;
+    }
+}
+
+gd::Dictionary Inventory::get_inventory_inspector() const {
+    gd::Dictionary dict{};
+    for(gd::KeyValue<Item const *, unsigned> const &item : this->inventory)
+        dict[item.key->get_class()] = item.value;
+    return dict;
+}

src/inventory.hpp

@@ -0,0 +1,47 @@
+#ifndef INVENTORY_HPP
+#define INVENTORY_HPP
+
+#include "item.hpp"
+#include "stats.hpp"
+#include "utils/godot_macros.hpp"
+#include <godot_cpp/classes/node.hpp>
+#include <godot_cpp/classes/ref_counted.hpp>
+#include <godot_cpp/templates/pair.hpp>
+#include <godot_cpp/templates/hash_map.hpp>
+
+namespace gd = godot;
+class Unit;
+
+class Inventory : public gd::Node {
+    GDCLASS(Inventory, gd::Node);
+    static void _bind_methods();
+public:
+    virtual void _ready() override;
+    Stats get_stats() const;
+    Item const *get_capability_for(ItemCapability const &capability, gd::Object *target) const;
+    void add_item(Item const *item, unsigned num);
+    unsigned get_item_amount(Item const *item);
+    bool has_item(Item const *item);
+
+    void set_weapon(Item const *weapon);
+    Item const *get_weapon() const;
+    void set_armour(Item const *weapon);
+    Item const *get_armour() const;
+
+    void set_weapon_id(int item_id);
+    int get_weapon_id() const;
+    void set_armour_id(int item_id);
+    int get_armour_id() const;
+    void set_inventory_inspector(gd::Dictionary dict);
+    gd::Dictionary get_inventory_inspector() const;
+private:
+    Item const *weapon{nullptr};
+    Item const *armour{nullptr};
+    Item const *helmet{nullptr};
+    Item const *utility{nullptr};
+    gd::HashMap<Item const *, unsigned> inventory{};
+
+    Unit *parent_unit{nullptr};
+};
+
+#endif // !INVENTORY_HPP

src/item.cpp

@@ -0,0 +1,35 @@
+#include "item.hpp"
+#include "unit.hpp"
+#include "utils/godot_macros.hpp"
+
+Item::~Item() {}
+
+bool Item::can_use_on(Unit *used_by, gd::Object *used_on) const {
+    return used_on != nullptr;
+}
+
+bool Item::try_use_on(Unit *used_by, gd::Object *used_on) const {
+    if(this->can_use_on(used_by, used_on)) {
+        this->use_on(used_by, used_on);
+        return true;
+    } else {
+        return false;
+    }
+}
+
+void Item::use_on(Unit *used_by, gd::Object *used_on) const {
+    if(used_on != nullptr)
+        gd::UtilityFunctions::push_warning(used_by->get_path(), " tried to use default Item::use_on implementation on object of type ", used_on->get_class());
+}
+
+Stats Item::get_stats() const {
+    return {};
+}
+
+bool Item::has_capability(ItemCapability const &capability) const {
+    return this->capabilities.has(capability);
+}
+
+ItemID Item::get_id() const {
+    return this->id;
+}

src/item.hpp

@@ -0,0 +1,70 @@
+#ifndef ITEM_HPP
+#define ITEM_HPP
+
+#include "stats.hpp"
+#include "goap/action.hpp"
+#include "utils/godot_macros.hpp"
+#include <godot_cpp/templates/hash_set.hpp>
+#include <godot_cpp/variant/utility_functions.hpp>
+
+namespace gd = godot;
+
+GDENUM(ItemCapability,
+    Heal,
+    Revive,
+    WeaponEquip,
+    WeaponRanged,
+    WeaponMelee,
+    ArmourEquip,
+    HeadEquip,
+    UtilityEquip,
+    Consume
+);
+
+typedef int ItemID;
+class Unit;
+
+class Item {
+friend class ItemDB;
+public:
+    static gd::StringName get_static_class() {
+        gd::UtilityFunctions::push_error("Calling Item::get_static_class() on an Item class that does not implement it. Use ITEM_CLASS(*) macro.");
+        return "Item";
+    }
+    virtual gd::StringName get_class() const {
+        gd::UtilityFunctions::push_error("Calling Item::get_class() on an Item class that does not implement it. Use ITEM_CLASS(*) macro.");
+        return "Item";
+    }
+    virtual gd::String get_display_name() const {
+        gd::UtilityFunctions::push_error("Calling Item::get_display_name() on an Item class that does not implement it. Use ITEM_CLASS(*) macro.");
+        return "<UNNAMED ITEM>";
+    }
+    virtual gd::String get_description() const {
+        gd::UtilityFunctions::push_error("Calling Item::get_description() on an Item class that does not implement it. Use ITEM_CLASS(*) macro.");
+        return "<UNDESCRIBED>";
+    }
+    Item() = default;
+    virtual ~Item();
+public:
+    virtual bool can_use_on(Unit *used_by, gd::Object *used_on) const;
+    bool try_use_on(Unit *used_by, gd::Object *used_on) const;
+    virtual Stats get_stats() const;
+    bool has_capability(ItemCapability const &capability) const;
+    ItemID get_id() const;
+protected:
+    virtual void use_on(Unit *used_by, gd::Object *used_on) const;
+protected:
+    gd::HashSet<uint32_t> capabilities{};
+private:
+    ItemID id{-1};
+};
+
+#define ITEM_CLASS(Class_, DisplayName_, Description_)\
+public: \
+    _FORCE_INLINE_ static godot::StringName get_static_class() { return #Class_; }\
+    _FORCE_INLINE_ virtual godot::StringName get_class() const override { return #Class_; }\
+    _FORCE_INLINE_ virtual godot::String get_display_name() const override { return DisplayName_; }\
+    _FORCE_INLINE_ virtual godot::String get_description() const override { return Description_; }\
+private:
+
+#endif // !ITEM_HPP

src/item_db.cpp

@@ -0,0 +1,58 @@
+#include "item_db.hpp"
+
+ItemDB::StaticData::~StaticData() {
+    if(this->hint != nullptr)
+        delete this->hint;
+    if(this->array_hint != nullptr)
+        delete this->array_hint;
+    for(Item *action : this->items)
+        delete action;
+}
+
+gd::String &ItemDB::StaticData::get_hint() {
+    if(this->hint == nullptr)
+        this->hint = new gd::String("None");
+    return *this->hint;
+}
+
+gd::String &ItemDB::StaticData::get_array_hint() {
+    if(this->array_hint == nullptr)
+        this->array_hint = new gd::String("None");
+    return *this->array_hint;
+}
+
+ItemID ItemDB::register_item(Item *item, gd::String item_name) {
+    item->id = ItemDB::data.items.size()+1;
+    ItemDB::data.get_hint() += ",";
+    ItemDB::data.get_hint() += item_name;
+    ItemDB::data.get_array_hint() = gd::vformat("%s/%s:%s", gd::Variant::INT, gd::PROPERTY_HINT_ENUM, ItemDB::data.get_hint());
+    ItemDB::data.items.push_back(item);
+    gd::UtilityFunctions::print("registered item type ", item_name);
+    return item->get_id();
+}
+
+Item const *ItemDB::get_item(ItemID index) {
+    index -= 1;
+    if(ItemDB::data.items.size() <= index || index < 0) {
+        gd::UtilityFunctions::push_warning("Attempted to get pointer to non-existent item type by ID ", index);
+        return nullptr;
+    }
+    return ItemDB::data.items[index];
+}
+
+gd::String const &ItemDB::get_enum_hint() {
+    return ItemDB::data.get_hint();
+}
+
+gd::String const &ItemDB::get_array_hint() {
+    return ItemDB::data.get_array_hint();
+}
+
+Item const *ItemDB::get_item_by_name(gd::StringName item_name) {
+    for(Item const *item : ItemDB::data.items)
+        if(item->get_class() == item_name)
+            return item;
+    return nullptr;
+}
+
+ItemDB::StaticData ItemDB::data{};

src/item_db.hpp

@@ -0,0 +1,34 @@
+#ifndef ITEM_DB_HPP
+#define ITEM_DB_HPP
+
+#include "item.hpp"
+#include <godot_cpp/templates/vector.hpp>
+
+namespace gd = godot;
+
+class ItemDB {
+    struct StaticData {
+        StaticData() = default;
+        ~StaticData();
+        gd::String &get_hint();
+        gd::String &get_array_hint();
+        gd::String *array_hint{};
+        gd::String *hint{};
+        gd::Vector<Item*> items{};
+    };
+    static ItemID register_item(Item *item, gd::String item_name);
+public:
+    static Item const *get_item(ItemID id);
+    static gd::String const &get_enum_hint();
+    static gd::String const &get_array_hint();
+    static Item const *get_item_by_name(gd::StringName item);
+
+    template <class TItem>
+    _FORCE_INLINE_ static ItemID register_item() {
+        return ItemDB::register_item(new TItem(), TItem::get_static_class());
+    }
+private:
+    static StaticData data;
+};
+
+#endif // !ITEM_DB_HPP

src/nav_room.cpp

@@ -6,7 +6,7 @@
 
 void NavRoom::_bind_methods() {
 #define CLASSNAME NavRoom
-    GDPROPERTY_HINTED(editor_neighbours, gd::Variant::ARRAY, gd::PROPERTY_HINT_ARRAY_TYPE, GDNODETYPE("NavRoom"));
+    GDPROPERTY_HINTED(neighbours_inspector, gd::Variant::ARRAY, gd::PROPERTY_HINT_ARRAY_TYPE, GDNODETYPE("NavRoom"));
 }
 
 NavRoom *NavRoom::get_closest_room(gd::Vector3 const &closest_to) {
@@ -44,14 +44,14 @@ gd::Vector<NavMarker*> const &NavRoom::get_markers() const {
     return this->markers;
 }
 
-gd::Array NavRoom::get_editor_neighbours() const {
+gd::Array NavRoom::get_neighbours_inspector() const {
     gd::Array a{};
     for(NavRoom *room : this->neighbours)
         a.push_back(room);
     return a;
 }
 
-void NavRoom::set_editor_neighbours(gd::Array array) {
+void NavRoom::set_neighbours_inspector(gd::Array array) {
     this->neighbours.clear();
     while(!array.is_empty()) if(NavRoom *room{gd::Object::cast_to<NavRoom>(array.pop_front())})
         this->neighbours.push_back(room);

src/nav_room.hpp

@@ -19,8 +19,8 @@ public:
     gd::Vector<NavRoom*> const &get_neighbours() const;
     gd::Vector<NavMarker*> const &get_markers() const;
 private:
-    void set_editor_neighbours(gd::Array array);
-    gd::Array get_editor_neighbours() const;
+    void set_neighbours_inspector(gd::Array array);
+    gd::Array get_neighbours_inspector() const;
 private:
     float radius{1.f};
     gd::Vector3 centre{0.f, 0.f, 0.f};

src/register_types.cpp

@@ -1,11 +1,13 @@
 #include "register_types.h"
 #include "enemy_world_state.hpp"
 #include "entity_health.hpp"
-#include "goap/state.hpp"
+#include "inventory.hpp"
+#include "item_db.hpp"
 #include "nav_marker.hpp"
 #include "nav_room.hpp"
 #include "rts_actions.hpp"
 #include "rts_game_mode.hpp"
+#include "rts_items.hpp"
 #include "rts_player.hpp"
 #include "rts_states.hpp"
 #include "unit.hpp"
@@ -15,6 +17,7 @@
 #include "goap/actor_world_state.hpp"
 #include "goap/goal.hpp"
 #include "goap/planner.hpp"
+#include "goap/state.hpp"
 #include "utils/register_types.hpp"
 #include <gdextension_interface.h>
 #include <godot_cpp/core/class_db.hpp>
@@ -31,7 +34,7 @@ void initialize_gdextension_types(gd::ModuleInitializationLevel p_level)
     utils::godot_cpp_utils_register_types();
 
     // always register actions before classes,
-    // so that ActionDB::get_enum_hint is complete before _bind_methods
+    // so that ActionDB::get_enum_hint is complete before _bind_methods.
     goap::ActionDB::register_action<MoveToTarget>();
     goap::ActionDB::register_action<FireAtTarget>();
     goap::ActionDB::register_action<FindTarget>();
@@ -40,24 +43,31 @@ void initialize_gdextension_types(gd::ModuleInitializationLevel p_level)
     goap::ActionDB::register_action<TankSelfHeal>();
     goap::ActionDB::register_action<TakeCover>();
 
-    gd::ClassDB::register_class<goap::ActorWorldState>();
-    gd::ClassDB::register_class<goap::Goal>();
-    gd::ClassDB::register_class<goap::Planner>();
-    gd::ClassDB::register_class<goap::State>();
+    // same for items,
+    // make sure ItemDB::get_enum_hint is fully populated out before _bind_methods.
+    ItemDB::register_item<Medkit>();
+    ItemDB::register_item<Handgun>();
+    ItemDB::register_item<Lasercutter>();
+    ItemDB::register_item<Welder>();
 
-    gd::ClassDB::register_class<MoveTo>();
-    gd::ClassDB::register_class<Animate>();
-    gd::ClassDB::register_class<Activate>();
+    GDREGISTER_CLASS(goap::ActorWorldState);
+    GDREGISTER_CLASS(goap::Goal);
+    GDREGISTER_CLASS(goap::Planner);
+    GDREGISTER_CLASS(goap::State);
 
-    gd::ClassDB::register_class<UnitWorldState>();
-    gd::ClassDB::register_class<EnemyWorldState>();
-    gd::ClassDB::register_class<GoalMarker>();
-    gd::ClassDB::register_class<Unit>();
-    gd::ClassDB::register_class<RTSGameMode>();
-    gd::ClassDB::register_class<RTSPlayer>();
-    gd::ClassDB::register_class<EntityHealth>();
-    gd::ClassDB::register_class<NavMarker>();
-    gd::ClassDB::register_class<NavRoom>();
+    GDREGISTER_CLASS(MoveTo);
+    GDREGISTER_CLASS(Animate);
+    GDREGISTER_CLASS(Activate);
+    GDREGISTER_CLASS(UnitWorldState);
+    GDREGISTER_CLASS(EnemyWorldState);
+    GDREGISTER_CLASS(GoalMarker);
+    GDREGISTER_CLASS(Unit);
+    GDREGISTER_CLASS(RTSGameMode);
+    GDREGISTER_CLASS(RTSPlayer);
+    GDREGISTER_CLASS(EntityHealth);
+    GDREGISTER_CLASS(NavMarker);
+    GDREGISTER_CLASS(NavRoom);
+    GDREGISTER_CLASS(Inventory);
 }
 
 extern "C"

src/rts_items.cpp

@@ -0,0 +1,46 @@
+#include "rts_items.hpp"
+#include "unit.hpp"
+#include "entity_health.hpp"
+
+Medkit::Medkit()
+: Item() {
+    this->capabilities.insert(ItemCapability::Consume);
+    this->capabilities.insert(ItemCapability::Heal);
+    this->capabilities.insert(ItemCapability::Revive);
+}
+
+bool Medkit::can_use_on(Unit *used_by, gd::Object *used_on) const {
+    return gd::Object::cast_to<Unit>(used_on) != nullptr;
+}
+
+void Medkit::use_on(Unit *used_by, gd::Object *used_on) const {
+    gd::Object::cast_to<Unit>(used_on)->get_entity_health()->healed_by(3, used_by);
+}
+
+Handgun::Handgun()
+: Item() {
+    this->capabilities.insert(ItemCapability::WeaponEquip);
+    this->capabilities.insert(ItemCapability::WeaponRanged);
+}
+
+bool Handgun::can_use_on(Unit *used_by, gd::Object *used_on) const {
+    return gd::Object::cast_to<Unit>(used_on) != nullptr
+        && used_by->get_world_state()->get_can_see_target();
+}
+
+void Handgun::use_on(Unit* used_by, gd::Object* used_on) const {
+    Unit *target{gd::Object::cast_to<Unit>(used_on)};
+    used_by->aim_at(target);
+    EntityHealth *health{target->get_entity_health()};
+    health->damaged_by(4, used_by);
+}
+
+Lasercutter::Lasercutter()
+: Item() {
+    this->capabilities.insert(ItemCapability::UtilityEquip);
+}
+
+Welder::Welder()
+: Item() {
+    this->capabilities.insert(ItemCapability::UtilityEquip);
+}

src/rts_items.hpp

@@ -0,0 +1,46 @@
+#ifndef RTS_ITEMS_HPP
+#define RTS_ITEMS_HPP
+
+#include "item.hpp"
+
+class Medkit : public Item {
+    ITEM_CLASS(Medkit, "Medkit",
+              "Standard emergency home medical kit. Use to manage wounds and stabilize a person.");
+public:
+    Medkit();
+    virtual bool can_use_on(Unit *used_by, gd::Object *used_on) const override;
+protected:
+    virtual void use_on(Unit *used_by, gd::Object *used_on) const override;
+};
+
+class Handgun : public Item {
+    ITEM_CLASS(Handgun, "9mm handgun.",
+              "A standard issue police firearm.");
+public:
+    Handgun();
+    virtual bool can_use_on(Unit *used_by, gd::Object *used_on) const override;
+protected:
+    virtual void use_on(Unit *used_by, gd::Object *used_on) const override;
+};
+
+class Lasercutter : public Item {
+    ITEM_CLASS(Lasercutter, "Lasercutter",
+              "A laser cutter, use to clear metal obstacles.");
+public:
+    Lasercutter();
+    // virtual bool can_use_on(Unit *used_by, gd::Object *object) const override;
+protected:
+    // virtual void use_on(Unit *used_by, gd::Object *object) const override;
+};
+
+class Welder : public Item {
+    ITEM_CLASS(Welder, "Welder",
+              "A welder with tanks intended to be carried on a person's back. Use to repair broken metal parts.");
+public:
+    Welder();
+    // virtual bool can_use_on(Unit *used_by, gd::Object *object) const override;
+protected:
+    // virtual void use_on(Unit *used_by, gd::Object *object) const override;
+};
+
+#endif // !RTS_ITEMS_HPP

src/stats.cpp

@@ -0,0 +1,15 @@
+#include "stats.hpp"
+#include <godot_cpp/core/math.hpp>
+
+namespace gd = godot;
+
+Stats operator &(Stats const &lhs, Stats const &rhs) {
+    Stats rval{};
+    rval.damage_absorb = gd::Math::min(lhs.damage_absorb + rhs.damage_absorb, 1.f);
+    rval.hazmat_level = gd::Math::max(lhs.hazmat_level, rhs.hazmat_level);
+    return rval;
+}
+
+Stats &operator <<(Stats &lhs, Stats const &rhs) {
+    return (lhs = lhs & rhs);
+}

src/stats.hpp

@@ -0,0 +1,17 @@
+#ifndef STATS_HPP
+#define STATS_HPP
+
+#include "utils/godot_macros.hpp"
+#include <godot_cpp/templates/hash_set.hpp>
+
+namespace gd = godot;
+
+struct Stats {
+    float damage_absorb{0.f};
+    int hazmat_level{0};
+};
+
+Stats operator &(Stats const &lhs, Stats const &rhs);
+Stats &operator <<(Stats &lhs, Stats const &rhs);
+
+#endif // !STATS_HPP

src/unit.cpp

@@ -29,6 +29,7 @@ void Unit::_enter_tree() { GDGAMEONLY();
     this->anim_player = this->get_node<gd::AnimationPlayer>("%AnimationPlayer");
     this->health = this->get_node<EntityHealth>("%EntityHealth");
     this->health->connect("death", callable_mp(this, &Unit::on_death));
+    this->inventory = this->get_node<Inventory>("%Inventory");
 }
 
 void Unit::_physics_process(double) { GDGAMEONLY();
@@ -78,15 +79,15 @@ void Unit::begin_goal(gd::Ref<goap::Goal> goal) {
 
 void Unit::use_weapon() {
     gd::Node3D *target{this->world_state->get_target_node()};
-    if(target == nullptr)
-        return;
-    if(!this->world_state->get_can_see_target())
-        return;
-    this->aim_at(target);
-    EntityHealth *health{target->get_node<EntityHealth>("EntityHealth")};
-    if(health == nullptr)
-        return;
-    health->damaged_by(1, this);
+    Item const *weapon{this->inventory->get_weapon()};
+    if(weapon == nullptr) {
+        // try and do a melee attack instead when no weapon is equipped
+        Unit *target_unit{gd::Object::cast_to<Unit>(target)};
+        if(target_unit != nullptr && this->world_state->get_can_see_target() && this->world_state->get_is_in_melee_range())
+            target_unit->get_entity_health()->damaged_by(1, this);
+    } else {
+        this->inventory->get_weapon()->try_use_on(this, target);
+    }
 }
 
 void Unit::aim_at(gd::Node3D *target) {

src/unit.hpp

@@ -2,6 +2,7 @@
 #define RTS_UNIT_HPP
 
 #include "goal_marker.hpp"
+#include "inventory.hpp"
 #include "unit_world_state.hpp"
 #include "goap/goal.hpp"
 #include "goap/planner.hpp"
@@ -69,6 +70,7 @@ protected:
     goap::Planner *planner{nullptr};
     EntityHealth *health{nullptr};
     UnitWorldState *world_state{nullptr};
+    Inventory *inventory{nullptr};
 #ifdef DEBUG_ENABLED
 public:
     gd::String DEBUG_print_debug_info();