source: GTP/trunk/App/Demos/Vis/FriendlyCulling/src/Polygon3.h @ 2913

#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