/*
 *  Ray++ - Object-oriented ray tracing library
 *  Copyright (C) 1998-2001 Martin Reinecke and others.
 *  See the AUTHORS file for more information.
 *
 *  This library is free software; you can redistribute it and/or
 *  modify it under the terms of the GNU Library General Public
 *  License as published by the Free Software Foundation; either
 *  version 2 of the License, or (at your option) any later version.
 *
 *  This library 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
 *  Library General Public License for more details.
 *
 *  You should have received a copy of the GNU Library General Public
 *  License along with this library; if not, write to the Free
 *  Software Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
 *
 *  See the README file for more information.
 */

#include "volumes/fog.h"

namespace RAYPP {

FOG::FOG ()
  : Colour (1,1,1), Distance (5), I_o_R (1) {}

FOG::FOG (const COLOUR &Col, float4 dist)
  : Colour (Col), Distance (dist), I_o_R (1) {}

//virtual
COLOUR FOG::Calc_new_Importance (const RAY &Ray) const
  {
  return Ray.Importance * exp ((Ray.mindist - Ray.maxdist)/Distance);
  }

//virtual
COLOUR FOG::Calc_Modified_Colour
  (const RAY &Ray, const COLOUR &Ingoing) const
  {
  float4 Fog_Factor= exp ((Ray.mindist-Ray.maxdist)/Distance);
  return (Fog_Factor*Ingoing + (1.0-Fog_Factor)*Colour);
  }

//virtual
COLOUR FOG::Get_Attenuated_Light
  (const RAY &Ray, const COLOUR &Ingoing) const
  {
  return Ingoing * exp ((Ray.mindist - Ray.maxdist)/Distance);
  }

void FOG::Set_Colour (const COLOUR &new_col)
  {
  Colour = new_col;
  }

void FOG::Set_Distance (float4 new_dist)
  {
  Distance = new_dist;
  }

void FOG::Set_Refractive_Index (float4 new_index)
  {
  I_o_R = new_index;
  }

} // namespace RAYPP