#ifndef __PVS_H
#define __PVS_H

#include "common.h"
#include "Bvh.h"

namespace CHCDemoEngine
{

class BvhNode;
class Bvh;

//#define USE_TIMESTAMPS

struct PvsEntry
{
	PvsEntry(SceneEntity *ent, float t): 
	mEntity(ent)
#ifdef USE_TIMESTAMPS
	, mTimeStamp(t)
#endif
	{}

	friend bool operator<(const PvsEntry &a, const PvsEntry &b);


	///////////////

	SceneEntity *mEntity;
#ifdef USE_TIMESTAMPS
	float mTimeStamp;
#endif
};




typedef std::vector<PvsEntry> PvsEntryContainer;


/** Class representing the Potentially Visible Set (PVS) from a view cell.
*/
class Pvs
{
public:

	void Clear();

	bool Empty() const;
	/** Convencience method adding all scene entities associated with a bvh node.
	*/
	void AddEntry(Bvh *bvh, BvhNode *node, float timeStamp = -1);

	int GetSize() const;

	inline SceneEntity *GetEntity(int i) const;
	
	inline PvsEntry GetEntry(int i) const;

	inline void AddEntry(const PvsEntry &entry);
	/* Sort entries by timestamp
	*/
	void Sort();


protected:

	/// vector of PVS entries
	PvsEntryContainer mEntries; 
};


inline SceneEntity *Pvs::GetEntity(int i) const 
{
	return mEntries[i].mEntity; 
}


inline PvsEntry Pvs::GetEntry(int i) const 
{
	return mEntries[i]; 
}


inline void Pvs::AddEntry(const PvsEntry &entry) 
{
	mEntries.push_back(entry);
}


inline int Pvs::GetSize() const
{ 
	return (int)mEntries.size(); 
}


inline void Pvs::AddEntry(Bvh *bvh, BvhNode *node, float timeStamp) 
{
	int geometrySize;
	SceneEntity **entities;
	entities = bvh->GetGeometry(node, geometrySize);

	for (int i = 0; i < geometrySize; ++ i)
	{
		AddEntry(PvsEntry(entities[i], timeStamp));
	}
}



}

#endif