/*************************************************************************/
/*  body_pair_2d_sw.h                                                    */
/*************************************************************************/
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#ifndef BODY_PAIR_2D_SW_H
#define BODY_PAIR_2D_SW_H

#include "body_2d_sw.h"
#include "constraint_2d_sw.h"

class BodyPair2DSW : public Constraint2DSW {
	enum {
		MAX_CONTACTS = 2
	};
	union {
		struct {
			Body2DSW *A;
			Body2DSW *B;
		};

		Body2DSW *_arr[2] = { nullptr, nullptr };
	};

	int shape_A = 0;
	int shape_B = 0;

	bool collide_A = false;
	bool collide_B = false;

	Space2DSW *space = nullptr;

	struct Contact {
		Vector2 position;
		Vector2 normal;
		Vector2 local_A, local_B;
		real_t acc_normal_impulse = 0.0; // accumulated normal impulse (Pn)
		real_t acc_tangent_impulse = 0.0; // accumulated tangent impulse (Pt)
		real_t acc_bias_impulse = 0.0; // accumulated normal impulse for position bias (Pnb)
		real_t mass_normal, mass_tangent = 0.0;
		real_t bias = 0.0;

		real_t depth = 0.0;
		bool active = false;
		Vector2 rA, rB;
		bool reused = false;
		real_t bounce = 0.0;
	};

	Vector2 offset_B; //use local A coordinates to avoid numerical issues on collision detection

	Vector2 sep_axis;
	Contact contacts[MAX_CONTACTS];
	int contact_count = 0;
	bool collided = false;
	bool oneway_disabled = false;
	bool report_contacts_only = false;

	bool _test_ccd(real_t p_step, Body2DSW *p_A, int p_shape_A, const Transform2D &p_xform_A, Body2DSW *p_B, int p_shape_B, const Transform2D &p_xform_B, bool p_swap_result = false);
	void _validate_contacts();
	static void _add_contact(const Vector2 &p_point_A, const Vector2 &p_point_B, void *p_self);
	_FORCE_INLINE_ void _contact_added_callback(const Vector2 &p_point_A, const Vector2 &p_point_B);

public:
	virtual bool setup(real_t p_step) override;
	virtual bool pre_solve(real_t p_step) override;
	virtual void solve(real_t p_step) override;

	BodyPair2DSW(Body2DSW *p_A, int p_shape_A, Body2DSW *p_B, int p_shape_B);
	~BodyPair2DSW();
};

#endif // BODY_PAIR_2D_SW_H