text: /*************************************************************************/
  /*  cpu_particles.h                                                      */
  /*************************************************************************/
  /*                       This file is part of:                           */
  /*                           GODOT ENGINE                                */
  /*                      https://godotengine.org                          */
  /*************************************************************************/
  /* Copyright (c) 2007-2019 Juan Linietsky, Ariel Manzur.                 */
  /* Copyright (c) 2014-2019 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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  /*************************************************************************/
  
  #ifndef CPU_PARTICLES_H
  #define CPU_PARTICLES_H
  
  #include "core/rid.h"
  #include "scene/3d/visual_instance.h"
  
  class CPUParticles : public GeometryInstance {
  private:
  	GDCLASS(CPUParticles, GeometryInstance);
  
  public:
  	enum DrawOrder {
  		DRAW_ORDER_INDEX,
  		DRAW_ORDER_LIFETIME,
  		DRAW_ORDER_VIEW_DEPTH,
  	};
  
  	enum Parameter {
  
  		PARAM_INITIAL_LINEAR_VELOCITY,
  		PARAM_ANGULAR_VELOCITY,
  		PARAM_ORBIT_VELOCITY,
  		PARAM_LINEAR_ACCEL,
  		PARAM_RADIAL_ACCEL,
  		PARAM_TANGENTIAL_ACCEL,
  		PARAM_DAMPING,
  		PARAM_ANGLE,
  		PARAM_SCALE,
  		PARAM_HUE_VARIATION,
  		PARAM_ANIM_SPEED,
  		PARAM_ANIM_OFFSET,
  		PARAM_MAX
  	};
  
  	enum Flags {
  		FLAG_ALIGN_Y_TO_VELOCITY,
  		FLAG_ROTATE_Y,
  		FLAG_DISABLE_Z,
  		FLAG_MAX
  	};
  
  	enum EmissionShape {
  		EMISSION_SHAPE_POINT,
  		EMISSION_SHAPE_SPHERE,
  		EMISSION_SHAPE_BOX,
  		EMISSION_SHAPE_POINTS,
  		EMISSION_SHAPE_DIRECTED_POINTS,
  	};
  
  private:
  	bool emitting;
  
  	struct Particle {
  		Transform transform;
  		Color color;
  		float custom[4];
  		Vector3 velocity;
  		bool active;
  		float angle_rand;
  		float scale_rand;
  		float hue_rot_rand;
  		float anim_offset_rand;
  		float time;
  		float lifetime;
  		Color base_color;
  
  		uint32_t seed;
  	};
  
  	float time;
  	float inactive_time;
  	float frame_remainder;
  	int cycle;
  	bool redraw;
  
  	RID multimesh;
  
  	PoolVector<Particle> particles;
  	PoolVector<float> particle_data;
  	PoolVector<int> particle_order;
  
  	struct SortLifetime {
  		const Particle *particles;
  
  		bool operator()(int p_a, int p_b) const {
  			return particles[p_a].time > particles[p_b].time;
  		}
  	};
  
  	struct SortAxis {
  		const Particle *particles;
  		Vector3 axis;
  		bool operator()(int p_a, int p_b) const {
  
  			return axis.dot(particles[p_a].transform.origin) < axis.dot(particles[p_b].transform.origin);
  		}
  	};
  
  	//
  
  	bool one_shot;
  
  	float lifetime;
  	float pre_process_time;
  	float explosiveness_ratio;
  	float randomness_ratio;
  	float lifetime_randomness;
  	float speed_scale;
  	bool local_coords;
  	int fixed_fps;
  	bool fractional_delta;
  
  	Transform inv_emission_transform;
  
  	volatile bool can_update;
  
  	DrawOrder draw_order;
  
  	Ref<Mesh> mesh;
  
  	////////
  
  	Vector3 direction;
  	float spread;
  	float flatness;
  
  	float parameters[PARAM_MAX];
  	float randomness[PARAM_MAX];
  
  	Ref<Curve> curve_parameters[PARAM_MAX];
  	Color color;
  	Ref<Gradient> color_ramp;
  
  	bool flags[FLAG_MAX];
  
  	EmissionShape emission_shape;
  	float emission_sphere_radius;
  	Vector3 emission_box_extents;
  	PoolVector<Vector3> emission_points;
  	PoolVector<Vector3> emission_normals;
  	PoolVector<Color> emission_colors;
  	int emission_point_count;
  
  	Vector3 gravity;
  
  	void _particles_process(float p_delta);
  	void _update_particle_data_buffer();
  
  	Mutex *update_mutex;
  
  	void _update_render_thread();
  
  	void _set_redraw(bool p_redraw);
  
  protected:
  	static void _bind_methods();
  	void _notification(int p_what);
  	virtual void _validate_property(PropertyInfo &property) const;
  
  public:
  	AABB get_aabb() const;
  	PoolVector<Face3> get_faces(uint32_t p_usage_flags) const;
  
  	void set_emitting(bool p_emitting);
  	void set_amount(int p_amount);
  	void set_lifetime(float p_lifetime);
  	void set_one_shot(bool p_one_shot);
  	void set_pre_process_time(float p_time);
  	void set_explosiveness_ratio(float p_ratio);
  	void set_randomness_ratio(float p_ratio);
  	void set_lifetime_randomness(float p_random);
  	void set_visibility_aabb(const AABB &p_aabb);
  	void set_use_local_coordinates(bool p_enable);
  	void set_speed_scale(float p_scale);
  
  	bool is_emitting() const;
  	int get_amount() const;
  	float get_lifetime() const;
  	bool get_one_shot() const;
  	float get_pre_process_time() const;
  	float get_explosiveness_ratio() const;
  	float get_randomness_ratio() const;
  	float get_lifetime_randomness() const;
  	AABB get_visibility_aabb() const;
  	bool get_use_local_coordinates() const;
  	float get_speed_scale() const;
  
  	void set_fixed_fps(int p_count);
  	int get_fixed_fps() const;
  
  	void set_fractional_delta(bool p_enable);
  	bool get_fractional_delta() const;
  
  	void set_draw_order(DrawOrder p_order);
  	DrawOrder get_draw_order() const;
  
  	void set_draw_passes(int p_count);
  	int get_draw_passes() const;
  
  	void set_mesh(const Ref<Mesh> &p_mesh);
  	Ref<Mesh> get_mesh() const;
  
  	///////////////////
  
  	void set_direction(Vector3 p_direction);
  	Vector3 get_direction() const;
  
  	void set_spread(float p_spread);
  	float get_spread() const;
  
  	void set_flatness(float p_flatness);
  	float get_flatness() const;
  
  	void set_param(Parameter p_param, float p_value);
  	float get_param(Parameter p_param) const;
  
  	void set_param_randomness(Parameter p_param, float p_value);
  	float get_param_randomness(Parameter p_param) const;
  
  	void set_param_curve(Parameter p_param, const Ref<Curve> &p_curve);
  	Ref<Curve> get_param_curve(Parameter p_param) const;
  
  	void set_color(const Color &p_color);
  	Color get_color() const;
  
  	void set_color_ramp(const Ref<Gradient> &p_ramp);
  	Ref<Gradient> get_color_ramp() const;
  
  	void set_particle_flag(Flags p_flag, bool p_enable);
  	bool get_particle_flag(Flags p_flag) const;
  
  	void set_emission_shape(EmissionShape p_shape);
  	void set_emission_sphere_radius(float p_radius);
  	void set_emission_box_extents(Vector3 p_extents);
  	void set_emission_points(const PoolVector<Vector3> &p_points);
  	void set_emission_normals(const PoolVector<Vector3> &p_normals);
  	void set_emission_colors(const PoolVector<Color> &p_colors);
  	void set_emission_point_count(int p_count);
  
  	EmissionShape get_emission_shape() const;
  	float get_emission_sphere_radius() const;
  	Vector3 get_emission_box_extents() const;
  	PoolVector<Vector3> get_emission_points() const;
  	PoolVector<Vector3> get_emission_normals() const;
  	PoolVector<Color> get_emission_colors() const;
  	int get_emission_point_count() const;
  
  	void set_gravity(const Vector3 &p_gravity);
  	Vector3 get_gravity() const;
  
  	virtual String get_configuration_warning() const;
  
  	void restart();
  
  	void convert_from_particles(Node *p_particles);
  
  	CPUParticles();
  	~CPUParticles();
  };
  
  VARIANT_ENUM_CAST(CPUParticles::DrawOrder)
  VARIANT_ENUM_CAST(CPUParticles::Parameter)
  VARIANT_ENUM_CAST(CPUParticles::Flags)
  VARIANT_ENUM_CAST(CPUParticles::EmissionShape)
  
  #endif // CPU_PARTICLES_H
  