/*************************************************************************/
/*  broad_phase_2d_hash_grid.h                                           */
/*************************************************************************/
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/*                           GODOT ENGINE                                */
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/*************************************************************************/
/* Copyright (c) 2007-2014 Juan Linietsky, Ariel Manzur.                 */
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/* a copy of this software and associated documentation files (the       */
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/* distribute, sublicense, and/or sell copies of the Software, and to    */
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/*************************************************************************/
#ifndef BROAD_PHASE_2D_HASH_GRID_H
#define BROAD_PHASE_2D_HASH_GRID_H

#include "broad_phase_2d_sw.h"
#include "map.h"

class BroadPhase2DHashGrid : public BroadPhase2DSW {


	struct PairData {

		bool colliding;
		int rc;
		void *ud;
		PairData() { colliding=false; rc=1; ud=NULL; }
	};

	struct Element {

		ID self;
		CollisionObject2DSW *owner;
		bool _static;
		Rect2 aabb;
		int subindex;
		uint64_t pass;
		Map<Element*,PairData*> paired;

	};


	Map<ID,Element> element_map;

	ID current;

	uint64_t pass;


	struct PairKey {

		union {
			struct {
				ID a;
				ID b;
			};
			uint64_t key;
		};

		_FORCE_INLINE_ bool operator<(const PairKey& p_key) const {
			return key < p_key.key;
		}

		PairKey() { key=0; }
		PairKey(ID p_a, ID p_b) { if (p_a>p_b) { a=p_b; b=p_a; } else { a=p_a; b=p_b; }}

	};


	Map<PairKey,PairData> pair_map;

	int cell_size;

	PairCallback pair_callback;
	void *pair_userdata;
	UnpairCallback unpair_callback;
	void *unpair_userdata;

	void _enter_grid(Element* p_elem, const Rect2& p_rect,bool p_static);
	void _exit_grid(Element* p_elem, const Rect2& p_rect,bool p_static);
	_FORCE_INLINE_ void _cull(const Point2i p_cell,CollisionObject2DSW** p_results,int p_max_results,int *p_result_indices,int &index);


	struct PosKey {

		union {
			struct {
				int32_t x;
				int32_t y;
			};
			uint64_t key;
		};


		_FORCE_INLINE_ uint32_t hash() const {
			uint64_t k=key;
			k = (~k) + (k << 18); // k = (k << 18) - k - 1;
			k = k ^ (k >> 31);
			k = k * 21; // k = (k + (k << 2)) + (k << 4);
			k = k ^ (k >> 11);
			k = k + (k << 6);
			k = k ^ (k >> 22);
			return k;
		}

		bool operator==(const PosKey& p_key) const { return key==p_key.key; }
		_FORCE_INLINE_ bool operator<(const PosKey& p_key) const {
			return key < p_key.key;
		}

	};

	struct RC {

		int ref;

		_FORCE_INLINE_ int inc() {
			ref++;
			return ref;
		}
		_FORCE_INLINE_ int dec() {
			ref--;
			return ref;
		}

		_FORCE_INLINE_ RC() {
			ref=0;
		}
	};

	struct PosBin {

		PosKey key;
		Map<Element*,RC> object_set;
		Map<Element*,RC> static_object_set;
		PosBin *next;
	};


	uint32_t hash_table_size;
	PosBin **hash_table;

	void _pair_attempt(Element *p_elem, Element* p_with);
	void _unpair_attempt(Element *p_elem, Element* p_with);
	void _check_motion(Element *p_elem);


public:

	virtual ID create(CollisionObject2DSW *p_object_, int p_subindex=0);
	virtual void move(ID p_id, const Rect2& p_aabb);
	virtual void set_static(ID p_id, bool p_static);
	virtual void remove(ID p_id);

	virtual CollisionObject2DSW *get_object(ID p_id) const;
	virtual bool is_static(ID p_id) const;
	virtual int get_subindex(ID p_id) const;

	virtual int cull_segment(const Vector2& p_from, const Vector2& p_to,CollisionObject2DSW** p_results,int p_max_results,int *p_result_indices=NULL);
	virtual int cull_aabb(const Rect2& p_aabb,CollisionObject2DSW** p_results,int p_max_results,int *p_result_indices=NULL);

	virtual void set_pair_callback(PairCallback p_pair_callback,void *p_userdata);
	virtual void set_unpair_callback(UnpairCallback p_unpair_callback,void *p_userdata);

	virtual void update();


	static BroadPhase2DSW *_create();

	BroadPhase2DHashGrid();
	~BroadPhase2DHashGrid();


};

#endif // BROAD_PHASE_2D_HASH_GRID_H