feat: npc follow logic

modules/authority/character.cpp

@@ -13,10 +13,12 @@ void Character::_bind_methods() {
 void Character::physics_process(double delta) {
 	Vector3 const velocity{ get_velocity() };
 	Vector3 new_velocity{ velocity };
-	new_velocity.x = this->world_movement_direction.x * this->data->get_speed();
-	new_velocity.z = this->world_movement_direction.y * this->data->get_speed();
+	new_velocity.x = this->world_movement_direction.x;
+	new_velocity.z = this->world_movement_direction.y;
 	set_velocity(new_velocity);
-	move_and_slide();
+	if (!velocity.is_zero_approx()) {
+		move_and_slide();
+	}
 }
 
 void Character::_notification(int what) {
@@ -35,6 +37,14 @@ void Character::_notification(int what) {
 	}
 }
 
+PackedStringArray Character::get_configuration_warnings() const {
+	PackedStringArray warnings{ super_type::get_configuration_warnings() };
+	if (this->data.is_null()) {
+		warnings.push_back("Character requires 'data' to be initialised. To avoid crashes consider adding a placeholder if you intend to programmatically initialise it.");
+	}
+	return warnings;
+}
+
 void Character::set_movement(Vector2 movement) {
 	this->world_movement_direction = movement;
 }
@@ -56,15 +66,24 @@ void CharacterState::_notification(int what) {
 			return;
 		case NOTIFICATION_ENTER_TREE:
 			this->character = cast_to<Character>(get_parent());
+			ERR_FAIL_COND_EDMSG(this->character == nullptr, "CharacterState requires parent to be of type Character");
 			return;
 		case NOTIFICATION_READY:
 			if (start_active) {
-				set_state_active(true);
+				callable_mp(this, &self_type::set_state_active).call_deferred(true);
 			}
 			return;
 	}
 }
 
+PackedStringArray CharacterState::get_configuration_warnings() const {
+	PackedStringArray warnings{ super_type::get_configuration_warnings() };
+	if (cast_to<Character>(get_parent()) == nullptr) {
+		warnings.push_back("CharacterState requires direct Character parent");
+	}
+	return warnings;
+}
+
 void CharacterState::switch_to_state(String value) {
 	if (!this->state_active) {
 		print_error(vformat("Attempt to switch from inactive state %s to new state %s", get_path(), value));

modules/authority/character.h

@@ -23,6 +23,7 @@ protected:
 	static void _bind_methods();
 	void physics_process(double delta);
 	void _notification(int what);
+	PackedStringArray get_configuration_warnings() const override;
 
 public:
 	void set_movement(Vector2 movement);
@@ -42,6 +43,7 @@ class CharacterState : public Node {
 
 protected:
 	void _notification(int what);
+	PackedStringArray get_configuration_warnings() const override;
 	void switch_to_state(String state);
 	void stack_state_dependent(String state);
 	void notify_dependent_inactive(CharacterState *dependent);

modules/authority/nav_marker.cpp

@@ -0,0 +1,13 @@
+#include "nav_marker.h"
+
+void NavMarker::_bind_methods() {}
+
+void NavMarker::_notification(int what) {
+	switch (what) {
+		default:
+			return;
+		case NOTIFICATION_ENTER_TREE:
+			this->set_gizmo_extents(3);
+			return;
+	}
+}

modules/authority/nav_marker.h

@@ -0,0 +1,19 @@
+#pragma once
+
+#include "authority/macros.h"
+#include "scene/3d/marker_3d.h"
+class Character;
+
+class NavMarker : public Marker3D {
+	GDCLASS(NavMarker, Marker3D);
+	static void _bind_methods();
+
+protected:
+	void _notification(int what);
+
+private:
+	Character *claimed{ nullptr };
+
+public:
+	GET_SET_FNS(Character *, claimed);
+};

modules/authority/party_member_states.cpp

@@ -0,0 +1,84 @@
+#include "party_member_states.h"
+#include "authority/nav_marker.h"
+#include "authority/player_character.h"
+#include "core/config/engine.h"
+#include "core/error/error_macros.h"
+#include "core/templates/vector.h"
+
+void PartyMemberFollow::_bind_methods() {}
+
+void PartyMemberFollow::process_position_target() {
+	Vector3 const marker_position{ this->claimed_marker->get_global_position() };
+	Vector3 const nav_target{ this->nav->get_target_position() };
+	Vector3 const global_position{ get_character()->get_global_position() };
+	if (global_position.distance_squared_to(marker_position) < 0.5) {
+		return;
+	}
+	if (nav_target.distance_squared_to(marker_position) > 0.25) {
+		this->nav->set_target_position(marker_position);
+	}
+	if (this->nav->is_navigation_finished()) {
+		return;
+	}
+	Vector3 velocity{ global_position.direction_to(this->nav->get_next_path_position()) };
+	velocity.y = 0;
+	if (this->nav->get_avoidance_enabled()) {
+		this->nav->set_velocity(velocity * get_character()->get_data()->get_speed());
+	} else {
+		push_movement_direction(velocity * get_character()->get_data()->get_speed());
+	}
+}
+
+void PartyMemberFollow::push_movement_direction(Vector3 velocity) {
+	get_character()->set_movement(Vector2{ velocity.x, velocity.z });
+}
+
+void PartyMemberFollow::_notification(int what) {
+	if (Engine::get_singleton()->is_editor_hint()) {
+		return;
+	}
+	switch (what) {
+		default:
+			return;
+		case NOTIFICATION_READY:
+			this->nav = cast_to<NavigationAgent3D>(get_parent()->get_node(NodePath("%NavigationAgent3D")));
+			ERR_FAIL_COND_EDMSG(this->nav == nullptr, "PartyMemberFollow cannot initialise without a navigation agent");
+			return;
+		case NOTIFICATION_PROCESS:
+			process_position_target();
+			return;
+	}
+}
+
+PackedStringArray PartyMemberFollow::get_configuration_warnings() const {
+	PackedStringArray warnings{ super_type::get_configuration_warnings() };
+	if (!get_parent()->has_node(NodePath("%NavigationAgent3D")) || !cast_to<NavigationAgent3D>(get_parent()->get_node(NodePath("%NavigationAgent3D")))) {
+		warnings.push_back("PartyMemberFollow expects a scene sibling of type NavigationAgent3D named with unique name '%NavigationAgent3D'");
+	}
+	return warnings;
+}
+
+void PartyMemberFollow::state_entered() {
+	Vector<NavMarker *> const &markers{ PlayerCharacter::get_singleton()->get_party_follow_markers() };
+	for (NavMarker *marker : markers) {
+		if (marker->get_claimed() == nullptr) {
+			marker->set_claimed(get_character());
+			this->claimed_marker = marker;
+			if (this->nav->get_avoidance_enabled()) {
+				this->nav->connect("velocity_computed", callable_mp(this, &self_type::push_movement_direction));
+			}
+			set_process(true);
+			return;
+		}
+	}
+	ERR_FAIL_EDMSG("PartyMemberFollow could not find an unclaimed player follow marker");
+	set_state_active(false);
+}
+
+void PartyMemberFollow::state_exited() {
+	if (this->claimed_marker) {
+		this->claimed_marker->set_claimed(nullptr);
+		this->nav->disconnect("velocity_computed", callable_mp(this, &self_type::push_movement_direction));
+		set_process(false);
+	}
+}

modules/authority/party_member_states.h

@@ -0,0 +1,22 @@
+#pragma once
+
+#include "authority/character.h"
+#include "authority/nav_marker.h"
+#include "scene/3d/navigation/navigation_agent_3d.h"
+
+class PartyMemberFollow : public CharacterState {
+	GDCLASS(PartyMemberFollow, CharacterState);
+	static void _bind_methods();
+	void process_position_target();
+	void push_movement_direction(Vector3 velocity);
+
+protected:
+	void _notification(int what);
+	PackedStringArray get_configuration_warnings() const override;
+	void state_entered() override;
+	void state_exited() override;
+
+private:
+	NavigationAgent3D *nav{ nullptr };
+	NavMarker *claimed_marker{ nullptr };
+};

modules/authority/player_camera.h

@@ -0,0 +1,8 @@
+#pragma once
+
+#include "scene/3d/camera_3d.h"
+
+class PlayerCamera : public Camera3D {
+	GDCLASS(PlayerCamera, Camera3D);
+	static void _bind_methods();
+};

modules/authority/player_character.cpp

@@ -0,0 +1,36 @@
+#include "player_character.h"
+#include "authority/nav_marker.h"
+
+void PlayerCharacter::_bind_methods() {}
+
+void PlayerCharacter::_notification(int what) {
+	if (Engine::get_singleton()->is_editor_hint()) {
+		return;
+	}
+	switch (what) {
+		default:
+			return;
+		case NOTIFICATION_ENTER_TREE:
+			instance = this;
+			return;
+		case NOTIFICATION_READY:
+			for (Variant var : find_children("*", "NavMarker")) {
+				if (NavMarker * marker{ cast_to<NavMarker>(var) }) {
+					this->party_follow_markers.push_back(marker);
+				}
+			}
+			ERR_FAIL_COND_EDMSG(this->party_follow_markers.size() < 4, "PlayerCharacter should have at least 4 follow NavMarkers for party members");
+			return;
+		case NOTIFICATION_EXIT_TREE:
+			if (instance == this) {
+				instance = nullptr;
+			}
+			return;
+	}
+}
+
+PlayerCharacter *PlayerCharacter::instance{ nullptr };
+
+PlayerCharacter *PlayerCharacter::get_singleton() {
+	return instance;
+}

modules/authority/player_character.h

@@ -0,0 +1,21 @@
+#pragma once
+
+#include "authority/character.h"
+#include "authority/macros.h"
+#include "authority/nav_marker.h"
+
+class PlayerCharacter : public Character {
+	GDCLASS(PlayerCharacter, Character);
+	static void _bind_methods();
+
+protected:
+	void _notification(int what);
+
+private:
+	Vector<NavMarker *> party_follow_markers{};
+	static PlayerCharacter *instance;
+
+public:
+	static PlayerCharacter *get_singleton();
+	GET_SET_FNS(Vector<NavMarker *> const &, party_follow_markers);
+};

modules/authority/player_states.cpp

@@ -32,7 +32,7 @@ void PlayerMovementState::process(double delta) {
 		backward = Vector2{ basis.get_column(1).x, basis.get_column(1).z };
 	}
 	Vector2 const right{ basis.get_column(2).x, basis.get_column(2).z };
-	get_character()->set_movement((backward.normalized() * this->movement.x + right.normalized() * this->movement.y));
+	get_character()->set_movement((backward.normalized() * this->movement.x + right.normalized() * this->movement.y) * get_character()->get_data()->get_speed());
 }
 
 void PlayerMovementState::_notification(int what) {

modules/authority/register_types.cpp

@@ -1,6 +1,9 @@
 #include "register_types.h"
 
 #include "authority/character.h"
+#include "authority/nav_marker.h"
+#include "authority/party_member_states.h"
+#include "authority/player_character.h"
 #include "authority/player_states.h"
 #include "core/object/class_db.h"
 
@@ -11,8 +14,11 @@ void initialize_authority_module(ModuleInitializationLevel p_level) {
 	ClassDB::register_class<CharacterData>();
 	ClassDB::register_class<Character>();
 	ClassDB::register_class<CharacterState>();
+	ClassDB::register_class<PlayerCharacter>();
 	ClassDB::register_class<PlayerInputState>();
 	ClassDB::register_class<PlayerMovementState>();
+	ClassDB::register_class<NavMarker>();
+	ClassDB::register_class<PartyMemberFollow>();
 }
 
 void uninitialize_authority_module(ModuleInitializationLevel p_level) {