gamma.h

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/*

Gamma Table Class

Copyright (C) 2000  Ryan Nunn

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.
*/

#ifndef INCL_GAMMA
#define INCL_GAMMA  1

#ifndef ALPHA_LINUX_CXX
#  include <cmath>
#endif

#ifndef UNDER_CE
using std::pow;
#endif

template <class T> class GammaTable
{
private:
  unsigned  size;
  float   sizef;
  T     *table;
  float   gamma;

  // No
  GammaTable() { }

public:

  inline const float & get_gamma ()
  { return gamma; }

  inline void set_gamma (float g)
  {
    if (g < 0.001f) g = 0.001f;
    if (g == gamma) return; 
    gamma = g;

    for (unsigned i = 0; i < size; i++)
      table[i] = (T) (pow (i / sizef, 1 / gamma) * sizef);
  }

  GammaTable (unsigned int s, float g = 1) : sizef(-1), gamma(-1)
  {
    sizef += size = s>2?s:2;  
    table = new T [size];
    set_gamma(g);
  }

  ~GammaTable () { delete [] table; }

  inline const T & operator [] (const T &i) const
  { return table[i]; }

};

#endif //INCL_GAMMA

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