SAH.h

/*
   Copyright (c) 2010 University of Illinois
   All rights reserved.
 
   Developed by:           DeNovo group, Graphis@Illinois
                           University of Illinois
                           http://denovo.cs.illinois.edu
                           http://graphics.cs.illinois.edu
 
   Permission is hereby granted, free of charge, to any person obtaining a
   copy of this software and associated documentation files (the
   "Software"), to deal with the Software without restriction, including
   without limitation the rights to use, copy, modify, merge, publish,
   distribute, sublicense, and/or sell copies of the Software, and to
   permit persons to whom the Software is furnished to do so, subject to
   the following conditions:
 
    * Redistributions of source code must retain the above copyright
      notice, this list of conditions and the following disclaimers.
 
    * Redistributions in binary form must reproduce the above
      copyright notice, this list of conditions and the following disclaimers
      in the documentation and/or other materials provided with the
      distribution.
 
    * Neither the names of DeNovo group, Graphics@Illinois, 
      University of Illinois, nor the names of its contributors may be used to 
      endorse or promote products derived from this Software without specific 
      prior written permission.
 
   THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
   OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
   MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.
   IN NO EVENT SHALL THE CONTRIBUTORS OR COPYRIGHT HOLDERS BE LIABLE FOR
   ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT,
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*/
 
#pragma once
#include <AtomsUtils/Globals.h>
#include <AtomsUtils/KdTree/Common.h>
#include <AtomsUtils/AtomsMath.h>
 
#define Ct_DEFAULT 15.0f
#define Ci_DEFAULT 20.0f
#define emptyBonus_DEFAULT 0.0f
 
namespace AtomsUtils
{
    class ATOMSUTILS_EXPORT SAH {
    public:
        SAH(float Ct = Ct_DEFAULT,
            float Ci = Ci_DEFAULT,
            float emptyBonus = emptyBonus_DEFAULT);
 
        float calculateSAH(const AtomsMath::Box3f &nodeExtent, char axis,
            unsigned int nA, unsigned int nB, float position) const;
 
        // convenient function
        float operator()(const AtomsMath::Box3f &nodeExtent, char axis,
            unsigned int nA, unsigned int nB, float position) const;
 
        // parameters in SAH formula
        const float m_Ci;          // triangle intersection cost
        const float m_Ct;            // node traversal cost
        const float m_emptyBonus;  // takes value between 0 and 1
                                   // closer to 1 => encourage empty space splitting
                                   // closer to 0 => discourage
    };
}