/*
 *  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.
 */

/*! \file spotlight.cxx
    \brief Implementation of the SPOTLIGHT class */

/* THIS FILE is copyright (c) 1999 by Ugo Varetto - varetto@computer.org */

#include "lights/spotlight.h"

namespace RAYPP {

extern HANDLE<WORLD> World;

// Constructors
SPOTLIGHT::SPOTLIGHT ()
  : Colour (1,1,1), Location (0,0,0), To (0,0,1), Dir(0,0,1), Exp(1),
    CutOff(0)
  {
  Attenuation[0]=0;
  Attenuation[1]=0;
  Attenuation[2]=1.0;
  }

SPOTLIGHT::SPOTLIGHT (const VECTOR &Loc,const VECTOR &to, const COLOUR &Col,
                      const float8 &e, const float8 &c)
  : Colour (Col), Location (Loc), To(to), Exp(e)
  {
  Attenuation[0]=0;
  Attenuation[1]=0;
  Attenuation[2]=1.0;
  CutOff= cos(radians(c));
  Dir=(To - Location).Norm();
  }

//virtual
void SPOTLIGHT::Init ()
  {
  if (initialized) return;
  World->Get_Surrounding_Volume (Location, MyVolume);
  initialized = true;
  }

//virtual
void SPOTLIGHT::Transform (const TRANSFORM &trans)
  {
  cni();
  Set_FromTo(trans.TransPoint (Location),trans.TransPoint (To));
  }

//virtual
void SPOTLIGHT::Cast_Light (const VECTOR &Pos, LIGHT_ARRAY &Arr) const
  {
  ci();
  VECTOR v = (Pos - Location);
  float8 d1 = v.Length();
  float8 d2 = d1*d1;
  VECTOR L = v.Norm();
  float8 cosangle = Dot(L,Dir); 
  float8 maxval= max<float8>(cosangle-CutOff,0.0);
  float8 att = pow(maxval,Exp)/
               (d2*Attenuation[2]+d1*Attenuation[1]+Attenuation[0]);
  COLOUR Col = Colour*att;
  if (!Col.TooSmall()) Arr.push_back (LIGHT_ENTRY (Col, Location, MyVolume));
  }

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

//virtual
void SPOTLIGHT::Set_Location (const VECTOR &new_loc)
  {
  cni();
  Location = new_loc;
  Dir=(To-Location).Norm();
  }
//virtual
void SPOTLIGHT::Set_To (const VECTOR &new_to)
  {
  cni();
  To = new_to;
  Dir=(To-Location).Norm();
  }

void SPOTLIGHT::Set_Exp (const float8 new_exp)
  {
  cni();
  Exp = new_exp;
  }

//virtual
void SPOTLIGHT::Set_FromTo (const VECTOR &new_loc,const VECTOR &new_to)
  {
  cni();
  Location = new_loc;
  To = new_to;
  Dir=(To-Location).Norm();
  }

void SPOTLIGHT::Set_CutOff(const float8 c)
  {
  cni();
  CutOff=cos(radians(c));
  }

void SPOTLIGHT::Set_Attenuation(const float8 a2,const float8 a1,
                                const float8 a0)
  {
  Attenuation[0]=a0;
  Attenuation[1]=a1;
  Attenuation[2]=a2;
  }

} // namespace RAYPP