source: GTP/trunk/Lib/Vis/Preprocessing/src/Polygon3.h @ 2116

#ifndef _Polygon3_h__
#define _Polygon3_h__


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

namespace GtpVisibilityPreprocessor {

class Polygon3;
class Plane3;
struct Face;
class Intersectable;
class AxisAlignedBox3;
class Ray;
class Mesh;
class MeshInstance;
class Material;
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 VertexContainer &vertices);
        /** Creates a polygon and stores pointer to parent mesh
                instance.
        */
        Polygon3(MeshInstance *parent);
        /** A Triangle is converted to a polygon.
        */
        Polygon3(const Triangle3 &tri);

        ~Polygon3();
        
        /** Copies all the vertices of the face.
        */
        Polygon3(Face *face, Mesh *parentMesh);
        
        /** Returns supporting plane of this polygon.
        */
        Plane3 GetSupportingPlane(); //const;

        /** Splits polygon.
                @param partition the split plane
                @param front returns the front 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,
                           const float epsilon);// = Limits::Small);

        /** 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 epsilon) 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, const float epsilon) const;

        /** Scales the polygon about its center
        */
        void Scale(const float scale);
        
        /** 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(const float epsilon) const; 

        /** Returns the surface normal.
        */
        Vector3 GetNormal() const;

        /** Casts ray to polygon.
        */
        int CastRay(const Ray &ray, float &t, const float nearestT);

        /** The polygon is converted to triangles.
        */
        void Triangulate(vector<Triangle3> &triangles) const;

        /** 
                Triangle strip indices are created from this polgon.
        */
        void Triangulate(VertexIndexContainer &indices) const;
        
        /** The piercing rays of the polygon are inherited by the child fragments
                @parm front_piece the front fragment inheriting the front rays
                @param back_piece the back fragment inheriting the back rays
        */
        void InheritRays(Polygon3 &front_piece, 
                                         Polygon3 &back_piece) const;

        /** Returns new polygon with reverse orientation.
        */
        Polygon3 *CreateReversePolygon() const;

        AxisAlignedBox3 GetBoundingBox() const;

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

        /** Classify polygons with respect to the plane.
            @returns one of BACK_SIDE, FRONT_SIDE, SPLIT, COINCIDENT
        */
        static int ClassifyPlane(const PolygonContainer &polys, 
                                                         const Plane3 &plane,
                                                         const float epsilon);

        /** Counts the number of different intersectables associated with the polygons.
        */
        static int ParentObjectsSize(const PolygonContainer &polys);

        /** Area of the accumulated polygons.
        */
        static float GetArea(const PolygonContainer &cell);

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

        /**
                Adds polygon to mesh description as a face
        */
        friend void IncludePolyInMesh(const Polygon3 &poly, Mesh &mesh);


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

        /// we can also store materials with polygons
        Material *mMaterial;
        
        /// pointer to the mesh instance this polygon is derived from
        MeshInstance *mParent;

        /// Rays piercing this polygon
        RayContainer mPiercingRays;

protected:

        Plane3 *mPlane;
};


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

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

        return s;
}

}

#endif