feat: implemented projectile pool

src/projectile_pool.cpp

@@ -0,0 +1,70 @@
+#include "projectile_pool.hpp"
+#include "projectile.hpp"
+#include <godot_cpp/classes/scene_state.hpp>
+#include <godot_cpp/variant/utility_functions.hpp>
+
+namespace godot {
+void ProjectilePool::_bind_methods() {
+#define CLASSNAME ProjectilePool
+}
+
+void ProjectilePool::_exit_tree() {
+    if(this->data.is_valid()) {
+        for(Node3D *node : this->inactive) {
+            node->queue_free();
+        }
+    }
+}
+
+void ProjectilePool::set_data(Ref<PackedScene> data) {
+    if(!this->data.is_null()) {
+        this->active.clear();
+        for(Node3D *node : this->inactive) {
+            node->queue_free();
+        }
+    }
+    this->data = data;
+    if(!data.is_valid())
+        return;
+    this->count = this->data->get_projectile_count() * this->data->get_rounds_per_second() * 2;
+    for(size_t i{0}; i < this->count; ++i)
+        this->inactive.push_back(this->instantiate_new());
+}
+
+Node3D *ProjectilePool::claim_projectile() {
+    if(inactive.is_empty()) {
+        size_t const new_count = this->count + this->data->get_projectile_count() * this->data->get_rounds_per_second() * 2;
+        for(size_t i{this->count}; i < new_count; ++i)
+            this->inactive.push_back(this->instantiate_new());
+    }
+    Node3D *const ret{this->inactive[0]};
+    this->inactive.remove_at(0);
+    this->active.push_back(ret);
+    return ret;
+}
+
+void ProjectilePool::return_projectile(Node3D *node) {
+    if(this->active.has(node)) {
+        this->active.erase(node);
+        this->inactive.push_back(node);
+        node->get_parent()->remove_child(node);
+    } else {
+        // leftover from previous weapon, free
+        node->queue_free(); 
+    }
+}
+
+Node3D *ProjectilePool::instantiate_new() const {
+    Ref<PackedScene> scene = this->data->get_projectile_scene();
+    if(!scene.is_valid() || !ClassDB::is_parent_class("Node3D", scene->get_state()->get_node_type(0)))
+        return nullptr;
+    Node3D *node = Object::cast_to<Node3D>(this->data->get_projectile_scene()->instantiate());
+    IProjectile *projectile = dynamic_cast<IProjectile*>(node);
+    if(projectile != nullptr) {
+        projectile->set_weapon_data(this->data);
+    } else {
+        UtilityFunctions::push_warning("Projectile scene ", scene->get_path(), "' root node does not implement IProjectile");
+    }
+    return node;
+}
+}

src/projectile_pool.hpp

@@ -0,0 +1,30 @@
+#ifndef PROJECTILE_POOL_HPP
+#define PROJECTILE_POOL_HPP
+
+#include "weapon_data.hpp"
+#include <godot_cpp/classes/node3d.hpp>
+#include <godot_cpp/templates/vector.hpp>
+
+namespace godot {
+class ProjectilePool : public Node {
+    GDCLASS(ProjectilePool, Node);
+    static void _bind_methods();
+public:
+    virtual void _exit_tree() override;
+    void set_data(Ref<PackedScene> data);
+    Ref<WeaponData> get_data() const;
+
+    Node3D *claim_projectile();
+    void return_projectile(Node3D *node);
+
+protected:
+    Node3D *instantiate_new() const;
+private:
+    Ref<WeaponData> data;
+    size_t count;
+    Vector<Node3D*> active{};
+    Vector<Node3D*> inactive{};
+};
+}
+
+#endif // !PROJECTILE_POOL_HPP