feat: first basic enemy patrolling behaviour

modules/wave_survival/npc_unit.cpp

@@ -0,0 +1,52 @@
+#include "npc_unit.h"
+#include "enemy_body.h"
+#include "macros.h"
+#include "patrol_path.h"
+
+void NpcUnit::_bind_methods() {
+	BIND_HPROPERTY(Variant::OBJECT, patrol_path, PROPERTY_HINT_NODE_TYPE, "PatrolPath");
+}
+
+void NpcUnit::child_added(Node *node) {
+	if (EnemyBody * npc{ cast_to<EnemyBody>(node) }) {
+		this->npcs.push_back(npc);
+		npc->set_unit(this);
+	}
+}
+
+void NpcUnit::enter_tree() {
+	this->connect("child_entered_tree", callable_mp(this, &self_type::child_added));
+}
+
+void NpcUnit::_notification(int what) {
+	if (Engine::get_singleton()->is_editor_hint()) {
+		return;
+	}
+	switch (what) {
+		default:
+			return;
+		case NOTIFICATION_ENTER_TREE:
+			enter_tree();
+			return;
+	}
+}
+
+void NpcUnit::set_patrol_path(PatrolPath *path) {
+	this->patrol_path = path;
+}
+
+PatrolPath *NpcUnit::get_patrol_path() const {
+	return this->patrol_path;
+}
+
+bool NpcUnit::is_aware_of_player() const {
+	return false;
+}
+
+void NpcUnit::set_patrol_speed(float speed) {
+	this->patrol_speed = speed;
+}
+
+float NpcUnit::get_patrol_speed() const {
+	return this->patrol_speed;
+}