#ifndef _ViewCell_H__
#define _ViewCell_H__

#include "Mesh.h"
#include "Containers.h"
#include "Ray.h"

//namespace GtpVisibilityPreprocessor {
  
class BspInterior;
class BspPvs;
struct Triangle3;
class BspLeaf;

/**
	View cell with an optional mesh representation
*/
class ViewCell: public MeshInstance
{
public:
	ViewCell();
	/** Constructor taking a mesh representing the shape of	the viewcell.
	*/
	ViewCell(Mesh *mesh);
	/** Returns PvS. 
	*/
	ViewCellPvs &GetPvs();

	int Type() const;

	/** Derives viewcells from object container.
		@param objects the intersectables the viewcells are derived from
		@param viewCells the viewcells are returned in this container
		@param maxViewCells the maximum number of viewcells created. if 0 => unbounded
	*/
	static void DeriveViewCells(const ObjectContainer &objects, 
															ViewCellContainer &viewCells, 
															const int maxViewCells);

	
	/** Adds a passing ray to the passing ray container.
	*/
	void AddPassingRay(const Ray &ray, const int contributions);	

	/** Constructs view cell from base triangle. The ViewCell is extruded along the normal vector.
		@param the base triangle
		@param the height of the newly created view cell
	*/
	static ViewCell *ExtrudeViewCell(const Triangle3 &baseTri, const float height);

	/** Merges two view cells.
		@note the piercing rays of the front and back will be ordered	
		@returns new view cell based on the merging.
	*/
	static ViewCell *Merge(ViewCell &front, ViewCell &back);

	/// Ray set description of the rays passing through this node.	
	PassingRaySet mPassingRays;

	/// Rays piercing this view cell.
	RayContainer mPiercingRays;

	/// view cells types
	enum HierarchyType {BSP, KD};

	/** Generates view cells of type specified by view cells type.
	*/
	static ViewCell *Generate(Mesh *mesh = NULL);

	/// type of view cells hierarchy (KD, BSP)
	static HierarchyType sHierarchy;

protected:

	/// the potentially visible objects
	ViewCellPvs mPvs;
};

class BspViewCell: public ViewCell
{
public:
	BspViewCell(): mBspLeaves(0) {}
	BspViewCell(Mesh *mesh): 
	ViewCell(mesh), mBspLeaves(0) {}

	/// Leaves which hold this view cell.
	vector<BspLeaf *> mBspLeaves;
};

#endif