/*************************************************************************/
/*  body_pair_sw.h                                                       */
/*************************************************************************/
/*                       This file is part of:                           */
/*                           GODOT ENGINE                                */
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/* Copyright (c) 2007-2017 Juan Linietsky, Ariel Manzur.                 */
/* Copyright (c) 2014-2017 Godot Engine contributors (cf. AUTHORS.md)    */
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/*************************************************************************/
#ifndef BODY_PAIR_SW_H
#define BODY_PAIR_SW_H

#include "body_sw.h"
#include "constraint_sw.h"

class BodyPairSW : public ConstraintSW {
	enum {

		MAX_CONTACTS = 4
	};

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

		BodySW *_arr[2];
	};

	int shape_A;
	int shape_B;

	struct Contact {

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

	Vector3 sep_axis;
	Contact contacts[MAX_CONTACTS];
	int contact_count;
	bool collided;
	int cc;

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

	void contact_added_callback(const Vector3 &p_point_A, const Vector3 &p_point_B);

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

	SpaceSW *space;

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

	BodyPairSW(BodySW *p_A, int p_shape_A, BodySW *p_B, int p_shape_B);
	~BodyPairSW();
};

#endif // BODY_PAIR__SW_H