/*************************************************************************/
/*  body_pair_3d_sw.h                                                    */
/*************************************************************************/
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#ifndef BODY_PAIR_3D_SW_H
#define BODY_PAIR_3D_SW_H

#include "body_3d_sw.h"
#include "constraint_3d_sw.h"
#include "core/templates/local_vector.h"
#include "soft_body_3d_sw.h"

class BodyContact3DSW : public Constraint3DSW {
protected:
	struct Contact {
		Vector3 position;
		Vector3 normal;
		int index_A, index_B;
		Vector3 local_A, local_B;
		real_t acc_normal_impulse; // accumulated normal impulse (Pn)
		Vector3 acc_tangent_impulse; // accumulated tangent impulse (Pt)
		real_t acc_bias_impulse; // accumulated normal impulse for position bias (Pnb)
		real_t acc_bias_impulse_center_of_mass; // accumulated normal impulse for position bias applied to com
		real_t mass_normal;
		real_t bias;
		real_t bounce;

		real_t depth;
		bool active;
		Vector3 rA, rB; // Offset in world orientation with respect to center of mass
	};

	Vector3 sep_axis;
	bool collided;

	Space3DSW *space;

	BodyContact3DSW(Body3DSW **p_body_ptr = nullptr, int p_body_count = 0) :
			Constraint3DSW(p_body_ptr, p_body_count) {
	}
};

class BodyPair3DSW : public BodyContact3DSW {
	enum {
		MAX_CONTACTS = 4
	};

	union {
		struct {
			Body3DSW *A;
			Body3DSW *B;
		};

		Body3DSW *_arr[2];
	};

	int shape_A;
	int shape_B;

	Vector3 offset_B; //use local A coordinates to avoid numerical issues on collision detection

	Contact contacts[MAX_CONTACTS];
	int contact_count;

	static void _contact_added_callback(const Vector3 &p_point_A, int p_index_A, const Vector3 &p_point_B, int p_index_B, void *p_userdata);

	void contact_added_callback(const Vector3 &p_point_A, int p_index_A, const Vector3 &p_point_B, int p_index_B);

	void validate_contacts();
	bool _test_ccd(real_t p_step, Body3DSW *p_A, int p_shape_A, const Transform &p_xform_A, Body3DSW *p_B, int p_shape_B, const Transform &p_xform_B);

public:
	bool setup(real_t p_step);
	void solve(real_t p_step);

	BodyPair3DSW(Body3DSW *p_A, int p_shape_A, Body3DSW *p_B, int p_shape_B);
	~BodyPair3DSW();
};

class BodySoftBodyPair3DSW : public BodyContact3DSW {
	Body3DSW *body;
	SoftBody3DSW *soft_body;

	int body_shape;

	LocalVector<Contact> contacts;

	static void _contact_added_callback(const Vector3 &p_point_A, int p_index_A, const Vector3 &p_point_B, int p_index_B, void *p_userdata);

	void contact_added_callback(const Vector3 &p_point_A, int p_index_A, const Vector3 &p_point_B, int p_index_B);

	void validate_contacts();

public:
	bool setup(real_t p_step);
	void solve(real_t p_step);

	BodySoftBodyPair3DSW(Body3DSW *p_A, int p_shape_A, SoftBody3DSW *p_B);
	~BodySoftBodyPair3DSW();
};

#endif // BODY_PAIR_3D_SW_H