text: /*************************************************************************/
  /*  tween.h                                                              */
  /*************************************************************************/
  /*                       This file is part of:                           */
  /*                           GODOT ENGINE                                */
  /*                      https://godotengine.org                          */
  /*************************************************************************/
  /* Copyright (c) 2007-2020 Juan Linietsky, Ariel Manzur.                 */
  /* Copyright (c) 2014-2020 Godot Engine contributors (cf. AUTHORS.md).   */
  /*                                                                       */
  /* Permission is hereby granted, free of charge, to any person obtaining */
  /* a copy of this software and associated documentation files (the       */
  /* "Software"), to deal in the Software without restriction, including   */
  /* without limitation the rights to use, copy, modify, merge, publish,   */
  /* distribute, sublicense, and/or sell copies of the Software, and to    */
  /* permit persons to whom the Software is furnished to do so, subject to */
  /* the following conditions:                                             */
  /*                                                                       */
  /* The above copyright notice and this permission notice shall be        */
  /* included in all copies or substantial portions of the Software.       */
  /*                                                                       */
  /* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,       */
  /* EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF    */
  /* MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.*/
  /* IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY  */
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  /* TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE     */
  /* SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.                */
  /*************************************************************************/
  
  #ifndef TWEEN_H
  #define TWEEN_H
  
  #include "scene/main/node.h"
  
  class Tween : public Node {
  	GDCLASS(Tween, Node);
  
  public:
  	enum TweenProcessMode {
  		TWEEN_PROCESS_PHYSICS,
  		TWEEN_PROCESS_IDLE,
  	};
  
  	enum TransitionType {
  		TRANS_LINEAR,
  		TRANS_SINE,
  		TRANS_QUINT,
  		TRANS_QUART,
  		TRANS_QUAD,
  		TRANS_EXPO,
  		TRANS_ELASTIC,
  		TRANS_CUBIC,
  		TRANS_CIRC,
  		TRANS_BOUNCE,
  		TRANS_BACK,
  
  		TRANS_COUNT,
  	};
  
  	enum EaseType {
  		EASE_IN,
  		EASE_OUT,
  		EASE_IN_OUT,
  		EASE_OUT_IN,
  
  		EASE_COUNT,
  	};
  
  private:
  	enum InterpolateType {
  
  		INTER_PROPERTY,
  		INTER_METHOD,
  		FOLLOW_PROPERTY,
  		FOLLOW_METHOD,
  		TARGETING_PROPERTY,
  		TARGETING_METHOD,
  		INTER_CALLBACK,
  	};
  
  	struct InterpolateData {
  		bool active;
  		InterpolateType type;
  		bool finish;
  		bool call_deferred;
  		real_t elapsed;
  		ObjectID id;
  		Vector<StringName> key;
  		StringName concatenated_key;
  		Variant initial_val;
  		Variant delta_val;
  		Variant final_val;
  		ObjectID target_id;
  		Vector<StringName> target_key;
  		real_t duration;
  		TransitionType trans_type;
  		EaseType ease_type;
  		real_t delay;
  		int args;
  		Variant arg[5];
  		int uid;
  		InterpolateData() {
  			active = false;
  			finish = false;
  			call_deferred = false;
  			uid = 0;
  		}
  	};
  
  	String autoplay;
  	TweenProcessMode tween_process_mode;
  	bool repeat;
  	float speed_scale;
  	mutable int pending_update;
  	int uid;
  
  	List<InterpolateData> interpolates;
  
  	struct PendingCommand {
  		StringName key;
  		int args;
  		Variant arg[10];
  	};
  	List<PendingCommand> pending_commands;
  
  	void _add_pending_command(StringName p_key, const Variant &p_arg1 = Variant(), const Variant &p_arg2 = Variant(), const Variant &p_arg3 = Variant(), const Variant &p_arg4 = Variant(), const Variant &p_arg5 = Variant(), const Variant &p_arg6 = Variant(), const Variant &p_arg7 = Variant(), const Variant &p_arg8 = Variant(), const Variant &p_arg9 = Variant(), const Variant &p_arg10 = Variant());
  	void _process_pending_commands();
  
  	typedef real_t (*interpolater)(real_t t, real_t b, real_t c, real_t d);
  	static interpolater interpolaters[TRANS_COUNT][EASE_COUNT];
  
  	real_t _run_equation(TransitionType p_trans_type, EaseType p_ease_type, real_t t, real_t b, real_t c, real_t d);
  	Variant &_get_delta_val(InterpolateData &p_data);
  	Variant _get_initial_val(const InterpolateData &p_data) const;
  	Variant _get_final_val(const InterpolateData &p_data) const;
  	Variant _run_equation(InterpolateData &p_data);
  	bool _calc_delta_val(const Variant &p_initial_val, const Variant &p_final_val, Variant &p_delta_val);
  	bool _apply_tween_value(InterpolateData &p_data, Variant &value);
  
  	void _tween_process(float p_delta);
  	void _remove_by_uid(int uid);
  	void _push_interpolate_data(InterpolateData &p_data);
  	void _build_interpolation(InterpolateType p_interpolation_type, Object *p_object, NodePath *p_property, StringName *p_method, Variant p_initial_val, Variant p_final_val, real_t p_duration, TransitionType p_trans_type, EaseType p_ease_type, real_t p_delay);
  
  protected:
  	bool _set(const StringName &p_name, const Variant &p_value);
  	bool _get(const StringName &p_name, Variant &r_ret) const;
  	void _get_property_list(List<PropertyInfo> *p_list) const;
  	void _notification(int p_what);
  
  	static void _bind_methods();
  
  public:
  	bool is_active() const;
  	void set_active(bool p_active);
  
  	bool is_repeat() const;
  	void set_repeat(bool p_repeat);
  
  	void set_tween_process_mode(TweenProcessMode p_mode);
  	TweenProcessMode get_tween_process_mode() const;
  
  	void set_speed_scale(float p_speed);
  	float get_speed_scale() const;
  
  	void start();
  	void reset(Object *p_object, StringName p_key);
  	void reset_all();
  	void stop(Object *p_object, StringName p_key);
  	void stop_all();
  	void resume(Object *p_object, StringName p_key);
  	void resume_all();
  	void remove(Object *p_object, StringName p_key);
  	void remove_all();
  
  	void seek(real_t p_time);
  	real_t tell() const;
  	real_t get_runtime() const;
  
  	void interpolate_property(Object *p_object, NodePath p_property, Variant p_initial_val, Variant p_final_val, real_t p_duration, TransitionType p_trans_type = TRANS_LINEAR, EaseType p_ease_type = EASE_IN_OUT, real_t p_delay = 0);
  	void interpolate_method(Object *p_object, StringName p_method, Variant p_initial_val, Variant p_final_val, real_t p_duration, TransitionType p_trans_type = TRANS_LINEAR, EaseType p_ease_type = EASE_IN_OUT, real_t p_delay = 0);
  	void interpolate_callback(Object *p_object, real_t p_duration, String p_callback, VARIANT_ARG_DECLARE);
  	void interpolate_deferred_callback(Object *p_object, real_t p_duration, String p_callback, VARIANT_ARG_DECLARE);
  	void follow_property(Object *p_object, NodePath p_property, Variant p_initial_val, Object *p_target, NodePath p_target_property, real_t p_duration, TransitionType p_trans_type = TRANS_LINEAR, EaseType p_ease_type = EASE_IN_OUT, real_t p_delay = 0);
  	void follow_method(Object *p_object, StringName p_method, Variant p_initial_val, Object *p_target, StringName p_target_method, real_t p_duration, TransitionType p_trans_type = TRANS_LINEAR, EaseType p_ease_type = EASE_IN_OUT, real_t p_delay = 0);
  	void targeting_property(Object *p_object, NodePath p_property, Object *p_initial, NodePath p_initial_property, Variant p_final_val, real_t p_duration, TransitionType p_trans_type = TRANS_LINEAR, EaseType p_ease_type = EASE_IN_OUT, real_t p_delay = 0);
  	void targeting_method(Object *p_object, StringName p_method, Object *p_initial, StringName p_initial_method, Variant p_final_val, real_t p_duration, TransitionType p_trans_type = TRANS_LINEAR, EaseType p_ease_type = EASE_IN_OUT, real_t p_delay = 0);
  
  	Tween();
  	~Tween();
  };
  
  VARIANT_ENUM_CAST(Tween::TweenProcessMode);
  VARIANT_ENUM_CAST(Tween::TransitionType);
  VARIANT_ENUM_CAST(Tween::EaseType);
  
  #endif
  