Polygon.h

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/*********************************************************\
 *  File: Polygon.h                                      *
 *
 *  Copyright (C) 2002-2012 The PixelLight Team (http://www.pixellight.org/)
 *
 *  This file is part of PixelLight.
 *
 *  PixelLight is free software: you can redistribute it and/or modify
 *  it under the terms of the GNU Lesser General Public License as published by
 *  the Free Software Foundation, either version 3 of the License, or
 *  (at your option) any later version.
 *
 *  PixelLight is distributed in the hope that it will be useful,
 *  but WITHOUT ANY WARRANTY; without even the implied warranty of
 *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
 *  GNU Lesser General Public License for more details.
 *
 *  You should have received a copy of the GNU Lesser General Public License
 *  along with PixelLight. If not, see <http://www.gnu.org/licenses/>.
\*********************************************************/


#ifndef __PLMATH_POLYGON_H__
#define __PLMATH_POLYGON_H__
#pragma once


//[-------------------------------------------------------]
//[ Includes                                              ]
//[-------------------------------------------------------]
#include <PLCore/Container/Array.h>
#include "PLMath/Plane.h"


//[-------------------------------------------------------]
//[ Namespace                                             ]
//[-------------------------------------------------------]
namespace PLMath {


//[-------------------------------------------------------]
//[ Classes                                               ]
//[-------------------------------------------------------]
/**
*  @brief
*    A polygon is a set of vertices on a same plane. This is only a base class with
*    vertices... to add texture coords etc. to have to derive it!
*/
class Polygon {


    //[-------------------------------------------------------]
    //[ Public definitions                                    ]
    //[-------------------------------------------------------]
    public:
        /**
        *  @brief
        *    Plane/point relation
        */
        enum ESide {
            Behind     = -1,    /**< Behind the plane (distance < 0) */
            Coinciding =  0,    /**< Lies on the plane (distance = 0) */
            InFront    =  1,    /**< Is in front of the plane (distance > 0) */
            Spanning   =  2     /**< Spans the plane */
        };


    //[-------------------------------------------------------]
    //[ Public functions                                      ]
    //[-------------------------------------------------------]
    public:
        /**
        *  @brief
        *    Constructor
        */
        PLMATH_API Polygon();

        /**
        *  @brief
        *    Copy constructor
        *
        *  @param[in] cSource
        *    Polygon to copy
        */
        PLMATH_API Polygon(const Polygon &cSource);

        /**
        *  @brief
        *    Destructor
        */
        PLMATH_API virtual ~Polygon();

        /**
        *  @brief
        *    Returns the plane the polygon is on
        *
        *  @return
        *    Plane the polygon is on
        */
        PLMATH_API const Plane &GetPlane() const;

        /**
        *  @brief
        *    Computes and returns the plane the polygon is on
        *
        *  @return
        *    Plane the polygon is on
        *
        *  @note
        *    - For the plane calculation the first three vertices are used
        */
        PLMATH_API const Plane &ComputePlane();

        /**
        *  @brief
        *    Checks whether all vertices are on the polygon plane or not
        *
        *  @return
        *    'true' if all vertices are on the polygon plane, else 'false'
        */
        PLMATH_API bool CheckVerticesOnPlane() const;

        /**
        *  @brief
        *    Returns a list of all vertices
        *
        *  @return
        *    List of all vertices
        *
        *  @note
        *    - If vertices are changed to should call the ComputePlane()
        *      function to keep the polygon plane up to date!
        */
        PLMATH_API PLCore::Array<Vector3> &GetVertexList();

        /**
        *  @brief
        *    Adds a vertex to the polygon
        *
        *  @param[in] vV
        *    Vertex to add
        *
        *  @return
        *    'true' if all went fine and the vertex was added, else 'false'
        *    (maybe the current last vertex is the same as the given one?)
        */
        PLMATH_API bool AddVertex(const Vector3 &vV);

        /**
        *  @brief
        *    Splits the polygon
        *
        *  @param[in]  cSplitter
        *    Splitter plane
        *  @param[out] cFrontPolygon
        *    Polygon in front of the plane
        *  @param[out] cBackPolygon
        *    Polygon behind the plane
        *
        *  @return
        *    'true' if all went fine, else 'false'
        */
        PLMATH_API bool Split(const Plane &cSplitter, Polygon &cFrontPolygon, Polygon &cBackPolygon);

        /**
        *  @brief
        *    Copy operator
        *
        *  @param[in] cSource
        *    Source to copy from
        *
        *  @return
        *    Reference to this instance
        */
        PLMATH_API Polygon &operator =(const Polygon &cSource);

        /**
        *  @brief
        *    Calculates the side the polygon is on
        *
        *  @return
        *    Plane side
        */
        PLMATH_API ESide GetSide(const Plane &cPlane) const;

        /**
        *  @brief
        *    Checks whether the polygon is completely in front of the given plane
        *
        *  @return
        *    'true' if the polygon is completely in front of the given plane, else 'false'
        */
        PLMATH_API bool IsInFront(const Plane &cPlane) const;

        /**
        *  @brief
        *    Checks whether the polygon is completely behind the given plane
        *
        *  @return
        *    'true' if the polygon is completely behind the given plane, else 'false'
        */
        PLMATH_API bool IsBehind(const Plane &cPlane) const;

        /**
        *  @brief
        *    Clips the polygon against a plane
        *
        *  @param[in] cPlane
        *    Plane to clip this polygon against
        *
        *  @return
        *    The resulting clipped plane
        */
        PLMATH_API Polygon Clip(const Plane &cPlane) const;


    //[-------------------------------------------------------]
    //[ Private data                                          ]
    //[-------------------------------------------------------]
    private:
        PLCore::Array<Vector3> m_lstVertices;   /**< The vertices (xyz) */
        Plane                  m_cPlane;        /**< Plane the polygon is on */


    //[-------------------------------------------------------]
    //[ Public virtual Polygon functions                      ]
    //[-------------------------------------------------------]
    public:
        /**
        *  @brief
        *    Initializes the data of the splitted polygon
        *
        *  @param[out] cPolygon
        *    Polygon which should be initialized
        *
        *  @return
        *    'true' if all went fine, else 'false'
        */
        PLMATH_API virtual bool CustomInit(Polygon &cPolygon);

        /**
        *  @brief
        *    Adds data to a polygon
        *
        *  @param[out] cPolygon
        *    Polygon the data should be added
        *  @param[in]  nID
        *    Current data ID
        *
        *  @return
        *    'true' if all went fine, else 'false'
        *
        *  @note
        *    - Is called by Split() to get an custom split behavior... a
        *      derived polygon could e.g. also have texture coordinates to be split or added!
        */
        PLMATH_API virtual bool CustomAdd(Polygon &cPolygon, PLCore::uint32 nID);

        /**
        *  @brief
        *    Splits the polygon using the custom function
        *
        *  @param[out] cFrontPolygon
        *    Polygon in front of the plane
        *  @param[out] cBackPolygon
        *    Polygon behind the plane
        *  @param[in]  nID
        *    Current data ID
        *  @param[in]  fDistance
        *    Distance from nID-1 to the splitter plane intersection point
        *
        *  @return
        *    'true' if all went fine, else 'false'
        *
        *  @see
        *    - CustomAdd()
        */
        PLMATH_API virtual bool CustomSplit(Polygon &cFrontPolygon, Polygon &cBackPolygon, PLCore::uint32 nID, float fDistance);


};


//[-------------------------------------------------------]
//[ Namespace                                             ]
//[-------------------------------------------------------]
} // PLMath


#endif // __PLMATH_POLYGON_H__