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sglLightProcessor.hpp

/*****************************************************************************
 * SGL: A Scene Graph Library
 *
 * Copyright (C) 1997-2001  Scott McMillan   All Rights Reserved.
 *
 * 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.
 *****************************************************************************
 *     File: sglLightProcessor.hpp
 *   Author: Tom Stimson
 *  Created: 20 April 2002
 *  Summary: Classes to sort and apply lights during cull and draw
 *****************************************************************************/

#ifndef __SGL_LIGHT_PROCESSOR_HPP
#define __SGL_LIGHT_PROCESSOR_HPP

#include <sgl.h>
#include <sglObject.hpp>
#include <sglMatrix.hpp>

#include <map>

class sglLight;

class SGL_DLL_API sglLightProcessor : public sglObject
{
public:
   sglLightProcessor() {}

   virtual ~sglLightProcessor() {}

   virtual void reset() = 0;

   virtual void addLight(const sglMat4f& matrix, const sglLight* light) = 0;

   virtual unsigned int getNumLights() const = 0;

   virtual void apply() = 0;
};


class SGL_DLL_API sglDefaultLightProcessor : public sglLightProcessor
{
public:
   sglDefaultLightProcessor() {}

   virtual ~sglDefaultLightProcessor() {}

   // See sglLightProcessor::reset() for details.
   virtual void reset() { m_light_list.clear(); }

   // See sglLightProcessor::addLight() for details.
   virtual void addLight(const sglMat4f& matrix, const sglLight* light);

   // See sglLightProcessor::getNumLights() for details.
   virtual unsigned int getNumLights() const { return m_light_list.size(); }

   // See sglLightProcessor::apply() for details.
   virtual void apply();

private:
   typedef pair<sglMat4f, const sglLight*> LightStruct;
   vector<LightStruct>  m_light_list;
};


class SGL_DLL_API sglSortedLightProcessor : public sglLightProcessor
{
public:
   sglSortedLightProcessor() {}

   virtual ~sglSortedLightProcessor() {}

   // See sglLightProcessor::reset() for details.
   virtual void reset()
      {
         m_inf_lights.clear();
         m_positional_lights.clear();
      }

   // See sglLightProcessor::addLight() for details.
   virtual void addLight(const sglMat4f& matrix, const sglLight* light);

   // See sglLightProcessor::getNumLights() for details.
   virtual unsigned int getNumLights() const
      { return m_inf_lights.size() + m_positional_lights.size(); }

   // See sglLightProcessor::apply() for details.
   virtual void apply();

private:
   typedef pair<sglMat4f, const sglLight*> LightStruct;
   typedef multimap<float, LightStruct, greater<float> > MapType;
   MapType m_inf_lights;
   MapType m_positional_lights;
};


class SGL_DLL_API sglCountSortedLightProcessor : public sglLightProcessor
{
public:
   sglCountSortedLightProcessor(unsigned int num_bins = 10);

   virtual ~sglCountSortedLightProcessor();

   // See sglLightProcessor::reset() for details.
   virtual void reset()
      {
         m_inf_lights.clear();
         m_positional_lights.clear();
      }

   // See sglLightProcessor::addLight() for details.
   virtual void addLight(const sglMat4f& matrix, const sglLight* light);

   // See sglLightProcessor::getNumLights() for details.
   virtual unsigned int getNumLights() const
      { return m_inf_lights.size() + m_positional_lights.size(); }

   // See sglLightProcessor::apply() for details.
   virtual void apply();

private:
   typedef float (*ValFunc)(const sglMat4f&, const sglLight*);

   struct LightStruct
   {
      LightStruct(const sglMat4f &matrix, const sglLight* light)
         : m_matrix(matrix), m_light(light) {}

      sglMat4f         m_matrix;
      const sglLight  *m_light;
      float            m_val;
      unsigned int     m_bin;
   };

   void sortLights(
      vector<LightStruct> &lights,
      ValFunc val_func,
      GLenum first_light,
      GLint max_lights,
      float &last_min_val,
      float &last_max_val);

private:
   vector<LightStruct>   m_inf_lights;
   vector<LightStruct>   m_positional_lights;
   unsigned int         *m_count;
   unsigned int          m_num_bins;
   float                 m_last_min_brightness;
   float                 m_last_max_brightness;
   float                 m_last_min_effect;
   float                 m_last_max_effect;
};

#endif

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