/*************************************************************************/
/*  gpu_particles_3d.h                                                   */
/*************************************************************************/
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/* Copyright (c) 2007-2021 Juan Linietsky, Ariel Manzur.                 */
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#ifndef PARTICLES_H
#define PARTICLES_H

#include "scene/3d/visual_instance_3d.h"
#include "scene/resources/skin.h"

class GPUParticles3D : public GeometryInstance3D {
private:
	GDCLASS(GPUParticles3D, GeometryInstance3D);

public:
	enum DrawOrder {
		DRAW_ORDER_INDEX,
		DRAW_ORDER_LIFETIME,
		DRAW_ORDER_REVERSE_LIFETIME,
		DRAW_ORDER_VIEW_DEPTH,
	};

	enum TransformAlign {
		TRANSFORM_ALIGN_DISABLED,
		TRANSFORM_ALIGN_Z_BILLBOARD,
		TRANSFORM_ALIGN_Y_TO_VELOCITY,
		TRANSFORM_ALIGN_Z_BILLBOARD_Y_TO_VELOCITY
	};

	enum {
		MAX_DRAW_PASSES = 4
	};

private:
	RID particles;

	bool one_shot;
	int amount;
	double lifetime;
	double pre_process_time;
	real_t explosiveness_ratio;
	real_t randomness_ratio;
	double speed_scale;
	AABB visibility_aabb;
	bool local_coords;
	int fixed_fps;
	bool fractional_delta;
	bool interpolate = true;
	NodePath sub_emitter;
	real_t collision_base_size = 0.01;

	bool trail_enabled = false;
	double trail_length = 0.3;

	TransformAlign transform_align = TRANSFORM_ALIGN_DISABLED;

	Ref<Material> process_material;

	DrawOrder draw_order;

	Vector<Ref<Mesh>> draw_passes;
	Ref<Skin> skin;

	void _attach_sub_emitter();

	void _skinning_changed();

protected:
	static void _bind_methods();
	void _notification(int p_what);
	virtual void _validate_property(PropertyInfo &property) const override;

public:
	AABB get_aabb() const override;
	Vector<Face3> get_faces(uint32_t p_usage_flags) const override;

	void set_emitting(bool p_emitting);
	void set_amount(int p_amount);
	void set_lifetime(double p_lifetime);
	void set_one_shot(bool p_one_shot);
	void set_pre_process_time(double p_time);
	void set_explosiveness_ratio(real_t p_ratio);
	void set_randomness_ratio(real_t p_ratio);
	void set_visibility_aabb(const AABB &p_aabb);
	void set_use_local_coordinates(bool p_enable);
	void set_process_material(const Ref<Material> &p_material);
	void set_speed_scale(double p_scale);
	void set_collision_base_size(real_t p_ratio);
	void set_trail_enabled(bool p_enabled);
	void set_trail_length(double p_seconds);

	bool is_emitting() const;
	int get_amount() const;
	double get_lifetime() const;
	bool get_one_shot() const;
	double get_pre_process_time() const;
	real_t get_explosiveness_ratio() const;
	real_t get_randomness_ratio() const;
	AABB get_visibility_aabb() const;
	bool get_use_local_coordinates() const;
	Ref<Material> get_process_material() const;
	double get_speed_scale() const;
	real_t get_collision_base_size() const;
	bool is_trail_enabled() const;
	double get_trail_length() 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_interpolate(bool p_enable);
	bool get_interpolate() 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_draw_pass_mesh(int p_pass, const Ref<Mesh> &p_mesh);
	Ref<Mesh> get_draw_pass_mesh(int p_pass) const;

	TypedArray<String> get_configuration_warnings() const override;

	void set_sub_emitter(const NodePath &p_path);
	NodePath get_sub_emitter() const;

	void set_skin(const Ref<Skin> &p_skin);
	Ref<Skin> get_skin() const;

	void set_transform_align(TransformAlign p_align);
	TransformAlign get_transform_align() const;

	void restart();

	enum EmitFlags {
		EMIT_FLAG_POSITION = RS::PARTICLES_EMIT_FLAG_POSITION,
		EMIT_FLAG_ROTATION_SCALE = RS::PARTICLES_EMIT_FLAG_ROTATION_SCALE,
		EMIT_FLAG_VELOCITY = RS::PARTICLES_EMIT_FLAG_VELOCITY,
		EMIT_FLAG_COLOR = RS::PARTICLES_EMIT_FLAG_COLOR,
		EMIT_FLAG_CUSTOM = RS::PARTICLES_EMIT_FLAG_CUSTOM
	};

	void emit_particle(const Transform3D &p_transform, const Vector3 &p_velocity, const Color &p_color, const Color &p_custom, uint32_t p_emit_flags);

	AABB capture_aabb() const;
	GPUParticles3D();
	~GPUParticles3D();
};

VARIANT_ENUM_CAST(GPUParticles3D::DrawOrder)
VARIANT_ENUM_CAST(GPUParticles3D::TransformAlign)
VARIANT_ENUM_CAST(GPUParticles3D::EmitFlags)

#endif // PARTICLES_H