source: downloads/OgreMain/include/OgreConvexBody.h @ 3

/*
-----------------------------------------------------------------------------
This source file is part of OGRE
(Object-oriented Graphics Rendering Engine)
For the latest info, see http://www.ogre3d.org/

Copyright (c) 2000-2006 Torus Knot Software Ltd
Copyright (c) 2006 Matthias Fink, netAllied GmbH <matthias.fink@web.de>                                                         
Also see acknowledgements in Readme.html

This program 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 2 of the License, or (at your option) any later
version.

This program 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
this program; if not, write to the Free Software Foundation, Inc., 59 Temple
Place - Suite 330, Boston, MA 02111-1307, USA, or go to
http://www.gnu.org/copyleft/lesser.txt.

You may alternatively use this source under the terms of a specific version of
the OGRE Unrestricted License provided you have obtained such a license from
Torus Knot Software Ltd.
-----------------------------------------------------------------------------
*/
#ifndef __ConvexBody_H__
#define __ConvexBody_H__

#include "OgrePrerequisites.h"
#include "OgrePolygon.h"


namespace Ogre
{

        /** Holds a solid representation of a convex body.
                @remarks
                        Administers a convex body. All polygons of the body are convex and
                        planar. Several operations may be applied, ranging from intersection
                        to join where each result it itself a convex body.
        */
        class _OgreExport ConvexBody
        {
        public:
                typedef std::vector< Polygon* > PolygonList;

        protected:
                PolygonList mPolygons;

                // Static 'free list' of polygons to save reallocation, shared between all bodies
                static PolygonList msFreePolygons;
#if OGRE_THREAD_SUPPORT
                static boost::recursive_mutex msFreePolygonsMutex;
#endif

        public:
                ConvexBody();
                ~ConvexBody();
                ConvexBody( const ConvexBody& cpy );

                /** Build a new polygon representation from a frustum.
                */
                void define(const Frustum& frustum);

                /** Build a new polygon representation from an AAB.
                */
                void define(const AxisAlignedBox& aab);

                /** Clips the body with a frustum. The resulting holes
                        are filled with new polygons.
                */
                void clip( const Frustum& frustum );

                /** Clips the body with an AAB. The resulting holes
                        are filled with new polygons.
                */
                void clip( const AxisAlignedBox& aab );

                /** Clips the body with another body.
                */
                void clip(const ConvexBody& body);

                /** Clips the object by the positive half space of a plane
                */
                void clip(const Plane& pl, bool keepNegative = true);

                /** Extends the existing body to incorporate the passed in point as a
                        convex hull.
                @remarks
                        You must already have constructed a basic body using a 'construct' 
                        method.
                */
                void extend(const Vector3& pt);

                /** Resets the object.
                */
                void reset( void );

                /** Returns the current number of polygons.
                */
                size_t getPolygonCount( void ) const;

                /** Returns the number of vertices for a polygon
                */
                size_t getVertexCount( size_t poly ) const;

                /** Returns a polygon.
                */
                const Polygon& getPolygon( size_t poly ) const;

                /** Returns a specific vertex of a polygon.
                */
                const Vector3& getVertex( size_t poly, size_t vertex ) const;

                /** Returns the normal of a specified polygon.
                */
                const Vector3& getNormal( size_t poly );

                /** Returns an AABB representation.
                */
                AxisAlignedBox getAABB( void ) const;

                /** Checks if the body has a closed hull.
                */
                bool hasClosedHull( void ) const;

                /** Merges all neighboring polygons into one single polygon if they are
                        lay in the same plane.
                */
                void mergePolygons( void );

                /** Determines if the current object is equal to the compared one.
                */
                bool operator == ( const ConvexBody& rhs ) const;

                /** Determines if the current object is not equal to the compared one.
                */
                bool operator != ( const ConvexBody& rhs ) const
                { return !( *this == rhs ); }

                /** Prints out the body with all its polygons.
                */
                _OgreExport friend std::ostream& operator<< ( std::ostream& strm, const ConvexBody& body );

                /** Log details of this body */
                void logInfo() const;

                /// Initialise the internal polygon pool used to minimise allocations
                static void _initialisePool();
                /// Tear down the internal polygon pool used to minimise allocations
                static void _destroyPool();


        protected:
                /** Get a new polygon from the pool.
                */
                static Polygon* allocatePolygon();
                /** Release a polygon back tot he pool. */
                static void freePolygon(Polygon* poly);
                /** Inserts a polygon at a partcular point in the body.
                @note
                        After this method is called, the ConvexBody 'owns' this Polygon
                        and will be responsible for deleting it.
                */
                void insertPolygon(Polygon* pdata, size_t poly);
                /** Inserts a polygon at the end.
                @note
                        After this method is called, the ConvexBody 'owns' this Polygon
                        and will be responsible for deleting it.
                */
                void insertPolygon(Polygon* pdata);

                /** Inserts a vertex for a polygon at a particular point.
                @note
                        No checks are done whether the assembled polygon is (still) planar, 
                        the caller must ensure that this is the case.
                */
                void insertVertex(size_t poly, const Vector3& vdata, size_t vertex);
                /** Inserts a vertex for a polygon at the end.
                @note
                        No checks are done whether the assembled polygon is (still) planar, 
                        the caller must ensure that this is the case.
                */
                void insertVertex(size_t poly, const Vector3& vdata);
                /** Deletes a specific polygon.
                */
                void deletePolygon(size_t poly);

                /** Removes a specific polygon from the body without deleting it.
                @note
                        The retrieved polygon needs to be deleted later by the caller.
                */
                Polygon* unlinkPolygon(size_t poly);

                /** Moves all polygons from the parameter body to this instance.
                @note Both the passed in object and this instance are modified
                */
                void moveDataFromBody(ConvexBody& body);

                /** Deletes a specific vertex of a specific polygon.
                */
                void deleteVertex(size_t poly, size_t vertex);

                /** Replace a polygon at a particular index.
                @note Again, the passed in polygon is owned by this object after this
                        call returns, and this object is resonsible for deleting it.
                */
                void setPolygon(Polygon* pdata, size_t poly );

                /** Replace a specific vertex of a polygon.
                @note
                        No checks are done whether the assembled polygon is (still) planar, 
                        the caller must ensure that this is the case.
                */
                void setVertex( size_t poly, const Vector3& vdata, size_t vertex );

                /** Returns the single edges in an EdgeMap (= edges where one side is a vertex and the
                        other is empty space (a hole in the body)).
                */
                Polygon::EdgeMap getSingleEdges() const;

                /** Stores the edges of a specific polygon in a passed in structure.
                */
                void storeEdgesOfPolygon(size_t poly, Polygon::EdgeMap *edgeMap) const;
                        
                /** Allocates space for an specified amount of polygons with
                        each of them having a specified number of vertices.
                        @note
                                Old data (if available) will be erased.
                */
                void allocateSpace(size_t numPolygons, size_t numVertices);

                /** Searches for a pair (an edge) in the intersectionList with an entry
                        that equals vec, and removes it from the passed in list.
                @param vec The vertex to search for in intersectionEdges
                @param intersectionEdges A list of edges, which is updated if a match is found
                @param vNext A reference to a vector which will be filled with the other
                        vertex at the matching edge, if found.
                @returns True if a match was found
                */
                bool findAndEraseEdgePair(const Vector3& vec, 
                        Polygon::EdgeMap& intersectionEdges, Vector3& vNext ) const;

        };
}

#endif