#ifndef _Polygon3_h__
#define _Polygon3_h__


#include "common.h"
#include "Vector3.h"
#include <iomanip>
#include <iostream>


namespace CHCDemoEngine 
{

	
class Polygon3;
class Plane3;
class AxisAlignedBox3;
struct Triangle3;



/** Class representing a planar convex polygon in 3d.
*/
class Polygon3
{
public:

	enum {BACK_SIDE, FRONT_SIDE, SPLIT, COINCIDENT};

	/** Default constructor creating an empty polygon.
	*/
	Polygon3();
	/** Constructor creating a polygon from the vertices.
	*/
	Polygon3(const VertexArray &vertices);

	~Polygon3();
	/** Returns supporting plane of this polygon.
	*/
	Plane3 GetSupportingPlane() const;
	/** Splits polygon.
		@param partition the split plane
		@param front returns the front polygon
		@param back returns the back polygon
		@param epsilon epsilon where two points are considered equal
	*/
	void Split(const Plane3 &partition, Polygon3 &front, Polygon3 &back, float eps);

	/** Returns the area of this polygon.
	*/
	float GetArea() const;
	
	/** Classify polygon with respect to the plane.
	    @param epsilon tolerance value
		@returns one of BACK_SIDE, FRONT_SIDE, SPLIT, COINCIDENT

	*/
	int ClassifyPlane(const Plane3 &plane, const float eps) const;
	/** Side of the polygon with respect to the plane.
		@returns 1 if on front side, -1 if on back side, 0 else.
	*/
	int Side(const Plane3 &plane, float eps) const;
	/** Computes the center of mass of the polygon
	 */
	Vector3 Center() const;
	/** Checks if the polygon is valid, i.e., not degenerated.
		@returns true if polygon is valid.
	*/
	bool Valid(float epsilon) const; 
	/** Returns the surface normal.
	*/
	Vector3 GetNormal() const;
	/** Returns new polygon with reverse orientation.
	*/
	Polygon3 *CreateReversePolygon() const;

	AxisAlignedBox3 GetBoundingBox() const;

	
	//////////////////////////////////////////
	
	/// vertices are connected in counterclockwise order.
	VertexArray mVertices;

};


// Overload << operator for C++-style output
inline std::ostream&
operator<< (std::ostream &s, const Polygon3 &A)
{
	VertexArray::const_iterator it;

	//s << setprecision(6) << "Polygon:\n";
	for (it = A.mVertices.begin(); it != A.mVertices.end(); ++ it)
	{
		s << *it << " ";
	}

	return s;
}

}

#endif