feat: first basic enemy patrolling behaviour

modules/wave_survival/enemies/enemy_wretched.cpp

@@ -0,0 +1,55 @@
+#include "enemy_wretched.h"
+#include "wave_survival/npc_unit.h"
+#include "wave_survival/patrol_path.h"
+#include "wave_survival/player_body.h"
+#include "wave_survival/state_machine.h"
+
+void EnemyWretched::_bind_methods() {
+}
+
+void EnemyWretched::ready() {
+	if (StateMachine * fsm{ cast_to<StateMachine>(get_node(NodePath("%StateMachine"))) }) {
+		fsm->add_state(memnew(WretchedPatrolState));
+	}
+}
+
+void EnemyWretched::_notification(int what) {
+	if (Engine::get_singleton()->is_editor_hint()) {
+		return;
+	}
+	switch (what) {
+		default:
+			return;
+		case NOTIFICATION_READY:
+			ready();
+			return;
+	}
+}
+
+void WretchedState::set_target(Node *node) {
+	this->target = cast_to<EnemyWretched>(node);
+}
+
+EnemyWretched *WretchedState::get_target() const {
+	return this->target;
+}
+
+void WretchedPatrolState::enter_state() {
+	this->nav = get_target()->get_nav();
+	this->path = get_target()->get_unit()->get_patrol_path();
+
+	float const max_speed{ get_target()->get_unit()->get_patrol_speed() };
+	get_target()->set_movement_speed(max_speed);
+	this->nav->set_max_speed(max_speed);
+	this->path_point = this->path->get_closest_point(get_target()->get_global_position());
+	this->nav->set_target_position(this->path->point_at(this->path_point));
+}
+
+void WretchedPatrolState::process(double delta) {
+	if (this->nav->is_navigation_finished()) {
+		this->path_point += 1;
+		this->nav->set_target_position(this->path->point_at(this->path_point));
+	}
+	Vector3 const direction{ get_target()->get_global_position().direction_to(this->nav->get_next_path_position()) };
+	get_target()->set_movement_direction(Vector2{ direction.x, direction.z }.normalized());
+}