ShadowVolumeGen.h

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// Copyright (C) 2005 Dave Griffiths
//
// This program is free software; you can redistribute it and/or modify
// it under the terms of the GNU 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 General Public License for more details.
//
// You should have received a copy of the GNU 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.


// Generates a shadow volume poly primitive for the supplied 
// primitives and light position

// Can we accelerate the process by caching as much as possible, and 
// changing only when light positions/primitive transforms/deform?

#include "Primitive.h"
#include "PolyPrimitive.h"
#include "NURBSPrimitive.h"

#ifndef N_SHADOWGEN
#define N_SHADOWGEN

namespace Fluxus
{

class ShadowVolumeGen
{
public:
    ShadowVolumeGen();
    ~ShadowVolumeGen(); 

    void SetLightPosition(dVector pos) { Clear(); m_LightPosition=pos; }
    
    void Clear();
    
    void Generate(Primitive *prim);
    
    PolyPrimitive *GetVolume();
    
    void SetLength(float s) { m_Length=s; }

    void SetExpand(float s) { m_Expand=s; }
    
    void SetDebug(bool s) { m_Debug=s; }
    bool GetDebug() { return m_Debug; }
    
private:

    typedef pair<int,int> EdgeType;
    typedef vector<EdgeType> EdgeContainer;
    typedef vector<EdgeContainer> SharedEdgeContainer;

    void PolyGen(PolyPrimitive *src);
    void NURBSGen(NURBSPrimitive *src);
    
    void AddEdge(dVector start, dVector end);
    int FindNextEdge(unsigned int index, vector<pair<dVector,dVector> > &silhouette, bool &flip);

    PolyPrimitive m_ShadowVolume;
    dVector m_LightPosition;
    float m_Length;
    float m_Expand;
    bool m_Debug;
};

};

#endif

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