feat: fully implemented death in NpcUnit

modules/wave_survival/enemy_body.cpp

@@ -19,11 +19,15 @@ void EnemyBody::on_child_added(Node *node) {
 void EnemyBody::ready() {
 	this->fsm = cast_to<StateMachine>(get_node(NodePath("%StateMachine")));
 	this->nav = cast_to<NavigationAgent3D>(get_node(NodePath("%NavigationAgent3D")));
+	this->health = cast_to<HealthStatus>(get_node(NodePath("%HealthStatus")));
 }
 
 void EnemyBody::physics_process(double delta) {
 	GETSET(velocity, {
 		velocity = Vector3{ this->movement_direction.x * this->movement_speed, velocity.y, this->movement_direction.y * this->movement_speed } + (velocity * delta);
+		if (!is_on_floor() && this->health->get_health() > 0) {
+			velocity += get_gravity() * delta;
+		}
 	});
 	if (!this->movement_direction.is_zero_approx()) {
 		look_at(get_global_position() + Vector3{ this->movement_direction.x, 0.f, this->movement_direction.y });

modules/wave_survival/npc_unit.cpp

@@ -11,18 +11,28 @@ void NpcUnit::_bind_methods() {
 	BIND_HPROPERTY(Variant::OBJECT, region, PROPERTY_HINT_NODE_TYPE, "MapRegion");
 }
 
+void NpcUnit::remove_npc(EnemyBody *npc) {
+	Transform3D const tf{ npc->get_global_transform() };
+	remove_child(npc);
+	this->get_parent()->add_child(npc);
+	npc->set_global_transform(tf);
+}
+
 void NpcUnit::on_npc_death() {
+	Vector<EnemyBody>::Size living{ this->npcs.size() };
 	// remove any dead npcs from the list
 	// leaving their bodies as separate nodes part of the tree
-	for (EnemyBody *npc : this->npcs) {
+	for (Vector<EnemyBody>::Size i{ 0 }; i < this->npcs.size(); ++i) {
+		EnemyBody *npc{ this->npcs[i] };
 		if (npc->get_health()->get_health() <= 0) {
-			this->get_parent()->add_child(npc);
-			this->npcs.erase(npc);
-			break;
+			--living;
 		}
 	}
 	// remove unit from world once all npcs are dead
-	if (this->npcs.size() <= 0) {
+	if (living == 0) {
+		for (EnemyBody *npc : this->npcs) {
+			remove_npc(npc);
+		}
 		this->set_region(nullptr); // de-register from region
 		this->queue_free();
 	}

modules/wave_survival/npc_unit.h

@@ -10,6 +10,7 @@ class MapRegion;
 class NpcUnit : public Node3D {
 	GDCLASS(NpcUnit, Node3D);
 	static void _bind_methods();
+	void remove_npc(EnemyBody *unit);
 	void on_npc_death();
 	void on_npc_awareness_changed(bool seen);
 	void child_added(Node *node);