feat: implemented initial checkpoint mechanic

modules/going/checkpoint.cpp

@@ -0,0 +1,65 @@
+#include "checkpoint.h"
+#include "core/config/engine.h"
+#include "going/player_body.h"
+#include "macros.h"
+
+void Checkpoint::_bind_methods() {
+	BIND_PROPERTY(Variant::VECTOR3, location);
+	BIND_PROPERTY(Variant::BOOL, can_jump);
+	BIND_PROPERTY(Variant::BOOL, can_bash);
+}
+
+void Checkpoint::set_location(Transform3D location) {
+	this->location = location;
+}
+
+Transform3D Checkpoint::get_location() const {
+	return this->location;
+}
+
+void Checkpoint::set_can_jump(bool can_jump) {
+	this->can_jump = can_jump;
+}
+
+bool Checkpoint::get_can_jump() const {
+	return this->can_jump;
+}
+
+void Checkpoint::set_can_bash(bool can_bash) {
+	this->can_bash = can_bash;
+}
+
+bool Checkpoint::get_can_bash() const {
+	return this->can_bash;
+}
+
+void Checkpoint::load(PlayerBody *body) const {
+	body->set_global_transform(this->location);
+	body->set_can_jump(this->can_jump);
+	// body->set_can_bash(this->can_bash);
+}
+
+void Checkpoint::save(PlayerBody *body) {
+	this->set_location(body->get_global_transform_interpolated());
+	this->set_can_jump(body->get_can_jump());
+	// self->set_can_bash(body->get_can_bash());
+}
+
+Ref<Checkpoint> Checkpoint::save_new(PlayerBody *body) {
+	Ref<Checkpoint> self{memnew(Checkpoint)};
+	self->save(body);
+	return self;
+}
+
+void CheckpointArea::_notification(int what) {
+	if(!Engine::get_singleton()->is_editor_hint() && what == NOTIFICATION_READY) {
+		this->connect(this->body_entered, callable_mp(this, &self_type::on_body_entered));
+	}
+}
+
+void CheckpointArea::on_body_entered(Node3D *body) {
+	if(PlayerBody *player{Object::cast_to<PlayerBody>(body)}) {
+		player->save_checkpoint();
+	}
+}
+

modules/going/checkpoint.h

@@ -0,0 +1,37 @@
+#ifndef CHECKPOINT_H
+#define CHECKPOINT_H
+
+#include "core/io/resource.h"
+#include "core/math/transform_3d.h"
+#include "scene/3d/node_3d.h"
+#include "scene/3d/physics/area_3d.h"
+class PlayerBody;
+
+class Checkpoint : public Resource {
+	GDCLASS(Checkpoint, Resource);
+	static void _bind_methods();
+public:
+	void set_location(Transform3D location);
+	Transform3D get_location() const;
+	void set_can_jump(bool can_jump);
+	bool get_can_jump() const;
+	void set_can_bash(bool can_bash);
+	bool get_can_bash() const;
+	
+	void load(PlayerBody *body) const;
+	void save(PlayerBody *body);
+	static Ref<Checkpoint> save_new(PlayerBody *body);
+private:
+	Transform3D location{};
+	bool can_jump{false}, can_bash{false};
+};
+
+class CheckpointArea : public Area3D {
+	GDCLASS(CheckpointArea, Area3D);
+	static void _bind_methods() {}
+	void _notification(int what);
+	void on_body_entered(Node3D *body);
+	StringName body_entered{"body_entered"};
+};
+
+#endif // !CHECKPOINT_H

modules/going/player_body.cpp

@@ -2,10 +2,12 @@
 #include "core/config/engine.h"
 #include "core/input/input.h"
 #include "core/math/math_funcs.h"
+#include "core/object/class_db.h"
+#include "macros.h"
+#include "player_states.h"
 #include "scene/3d/camera_3d.h"
 #include "scene/animation/animation_player.h"
 #include "scene/main/viewport.h"
-#include "macros.h"
 
 char *const PlayerBody::split_step_action{const_cast<char*>("split_step")};
 char *const PlayerBody::move_left_action{const_cast<char*>("move_left")};
@@ -16,6 +18,8 @@ char *const PlayerBody::move_back_action{const_cast<char*>("move_back")};
 void PlayerBody::_bind_methods() {
 	ClassDB::bind_method(D_METHOD("get_desired_velocity"), &self_type::get_desired_velocity);
 	ClassDB::bind_method(D_METHOD("get_desired_direction"), &self_type::get_desired_direction);
+	ClassDB::bind_method(D_METHOD("save_checkpoint"), &self_type::save_checkpoint);
+	ClassDB::bind_method(D_METHOD("load_checkpoint"), &self_type::load_checkpoint);
 
 	BIND_PROPERTY(Variant::FLOAT, stopping_deceleration);
 	BIND_PROPERTY(Variant::FLOAT, start_speed);
@@ -58,6 +62,7 @@ void PlayerBody::enter_tree() {
 	this->anim = Object::cast_to<AnimationPlayer>(this->get_node(NodePath("character/AnimationPlayer")));
 	this->camera = Object::cast_to<Camera3D>(this->get_node(NodePath("Camera3D")));
 	this->camera->set_fov(this->min_fov);
+	this->last_checkpoint = Checkpoint::save_new(this);
 }
 
 void PlayerBody::process(double delta) {
@@ -74,6 +79,15 @@ void PlayerBody::physics_process(double delta) {
 	this->move_and_slide();
 }
 
+void PlayerBody::save_checkpoint() {
+	this->last_checkpoint->save(this);
+}
+
+void PlayerBody::load_checkpoint() {
+	this->last_checkpoint->load(this);
+	this->state->force_state<FallingState>();
+}
+
 Vector3 PlayerBody::get_desired_direction() const {
 	Basis const global{this->camera->get_global_basis()};
 	Vector3 forward{global.get_column(2)};

modules/going/player_body.h

@@ -1,9 +1,11 @@
 #ifndef PLAYER_BODY_H
 #define PLAYER_BODY_H
 
+#include "going/checkpoint.h"
 #include "scene/3d/camera_3d.h"
 #include "scene/3d/physics/character_body_3d.h"
 #include "scene/animation/animation_player.h"
+class PlayerStateMachine;
 
 class PlayerBody : public CharacterBody3D {
 	GDCLASS(PlayerBody, CharacterBody3D);
@@ -14,6 +16,8 @@ class PlayerBody : public CharacterBody3D {
 	void physics_process(double delta);
 
 public:
+	void save_checkpoint();
+	void load_checkpoint();
 	Vector3 get_desired_direction() const;
 	Vector3 get_desired_velocity() const;
 	Vector2 get_movement_input() const;
@@ -71,6 +75,8 @@ private:
 	float model_lean_speed{0.25f};
 	double game_over_speed{1.0/4.0};
 	bool can_jump{false};
+	Ref<Checkpoint> last_checkpoint{nullptr};
+	PlayerStateMachine *state{nullptr};
 public:
 	static char *const split_step_action;
 	static char *const move_left_action;

modules/going/player_states.cpp

@@ -30,7 +30,7 @@ void StandingState::process(double delta) {
 	this->game_over_timer += delta * this->get_body()->get_game_over_speed();
 	if(this->game_over_timer > 1.0) {
 		RenderingServer::get_singleton()->global_shader_parameter_set(this->game_over_param, 0.0);
-		SceneTree::get_singleton()->reload_current_scene();
+		this->get_body()->load_checkpoint();
 	} else {
 		RenderingServer::get_singleton()->global_shader_parameter_set(this->game_over_param, float(this->game_over_timer));
 		this->game_over_timer = MIN(this->game_over_timer, 1.f);
@@ -78,7 +78,7 @@ void RunningState::process_lean(double delta) {
 		Vector3 const up{Vector3{0.0, 1.0, 0.0} + Vector3{cross.x, 0.f, cross.y} * this->lean_modifier};
 		Vector3 const forward{current.x, 0.f, current.z};
 		if(!forward.is_zero_approx()) {
-			this->get_body()->get_model()->look_at(this->get_body()->get_global_position() - current, up);
+			this->get_body()->get_model()->look_at(this->get_body()->get_global_position() - forward, up);
 		}
 	}
 }
@@ -100,18 +100,20 @@ void RunningState::physics_process(double delta) {
 
 void RunningState::state_exited() {
 	Vector3 const velocity{this->get_body()->get_velocity()};
-	Vector3 const velocity_flat{velocity.x, 0.f, velocity.z};
-	if(!velocity_flat.is_zero_approx()) {
-		this->get_body()->get_model()->look_at(this->get_body()->get_global_position() - velocity_flat);
+	Vector3 velocity_flat{velocity.x, 0.f, velocity.z};
+	if(velocity_flat.is_zero_approx()) {
+		velocity_flat = this->get_body()->get_model()->get_global_basis().get_column(2);
 	}
+	this->get_body()->get_model()->look_at(this->get_body()->get_global_position() - velocity_flat);
 	this->lean_modifier = 0.f;
 }
 
 PlayerState::StateID SplitStepState::get_next_state() const {
-	if(!this->get_body()->is_on_floor()) {
-		return FallingState::get_class_static();
-	} else if(this->get_body()->get_can_jump() && this->jump && this->timer <= 0.0) {
+	 bool const jump_input{this->get_body()->get_can_jump() && this->jump};
+	if(jump_input && (this->timer <= 0.0 || !this->get_body()->is_on_floor())) {
 		return JumpingState::get_class_static();
+	} else if(!this->get_body()->is_on_floor()) {
+		return FallingState::get_class_static();
 	} else if(this->timer <= 0.0) {
 		return RunningState::get_class_static();
 	} else {
@@ -169,7 +171,7 @@ void FallingState::process(double delta) {
 		this->game_over_timer += delta * this->get_body()->get_game_over_speed();
 		if(this->game_over_timer > 1.0) {
 			RenderingServer::get_singleton()->global_shader_parameter_set(this->game_over_param, 0.0);
-			SceneTree::get_singleton()->reload_current_scene();
+			this->get_body()->load_checkpoint();
 		} else {
 			RenderingServer::get_singleton()->global_shader_parameter_set(this->game_over_param, float(this->game_over_timer));
 			this->game_over_timer = MIN(this->game_over_timer, 1.f);

modules/going/player_states.h

@@ -92,7 +92,10 @@ class PlayerStateMachine : public Node {
 	void try_transition();
 	template <class TState>
 	void add_state();
-
+public:
+	template <class TState>
+	void force_state();
+private:
 	PlayerBody *body{nullptr};
 	PlayerState *current_state{nullptr};
 	HashMap<PlayerState::StateID, PlayerState*> states;
@@ -100,7 +103,7 @@ class PlayerStateMachine : public Node {
 
 template <class TState>
 void PlayerStateMachine::add_state() {
-	PlayerState *state{new TState()};
+	PlayerState *state{memnew(TState)};
 	state->body = this->body;
 	this->states.insert(TState::get_class_static(), state);
 	if(this->current_state == nullptr) {
@@ -109,4 +112,9 @@ void PlayerStateMachine::add_state() {
 	}
 }
 
+template <class TState>
+void PlayerStateMachine::force_state() {
+	this->states[TState::get_class_static()];
+}
+
 #endif // !PLAYER_STATES_H

modules/going/register_types.cpp

@@ -1,6 +1,7 @@
 #include "register_types.h"
 
 #include "core/object/class_db.h"
+#include "going/checkpoint.h"
 #include "going/game_ui.h"
 #include "going/player_body.h"
 #include "going/player_states.h"
@@ -18,6 +19,8 @@ void initialize_going_module(ModuleInitializationLevel p_level) {
 	ClassDB::register_class<JumpingState>();
 	ClassDB::register_class<PlayerStateMachine>();
 	ClassDB::register_class<GameUI>();
+	ClassDB::register_class<Checkpoint>();
+	ClassDB::register_class<CheckpointArea>();
 }
 
 void uninitialize_going_module(ModuleInitializationLevel p_level) {