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c:/home/kevn/src/animaniac/ani/Dynamics/operators/ColorWithAgeOperator.h

Go to the documentation of this file.

#ifndef COLOR_WITH_AGE_OPERATOR
#define COLOR_WITH_AGE_OPERATOR

#include <vector>
#include <gmtl/Vec.h>
#include <gmtl/VecOps.h>

namespace ani
{
   template<class __EntityType>
   class ColorWithAgeOperator : public ani::Operator<__EntityType>
   {
   public:
      typedef boost::shared_ptr<__EntityType> EntityTypePtr;

   public:
      ColorWithAgeOperator() : ani::Operator<__EntityType>()
      {
         // set some default colors to cycle through
         gmtl::Vec4f a;
         a.set( 1.0f, 0.0f, 0.0f, 1.0f );
         mColorTransitions.push_back( a );

         a.set( 0.0f, 1.0f, 0.0f, 0.7f );
         mColorTransitions.push_back( a );

         a.set( 0.0f, 0.0f, 1.0f, 0.3f );
         mColorTransitions.push_back( a );
      }
      virtual ~ColorWithAgeOperator() {}

      // colors to interpolate between
      void setColors( std::vector<gmtl::Vec4f>& colorTransitions ) { mColorTransitions = colorTransitions; }
      virtual void exec( DynamicSystem<__EntityType>& ps, float timeDelta );

      std::vector<gmtl::Vec4f> mColorTransitions;
   };

   template <class __EntityType>
   void ColorWithAgeOperator<__EntityType>::exec(  DynamicSystem<__EntityType>& ps, float timeDelta )
   {
      std::vector<EntityTypePtr>::iterator it;
      for (it = ps.entities().begin(); it != ps.entities().end();
      ++it)
      {
         EntityTypePtr p = *it;
         float age__zero_to_one = p->age() / p->ageOfDeath();

         // find the range that we'll examine... range = {0...(size-1)} so that we can always check i and i+1
         // NOTE: range will at least be 0, since size >= 1
         assert( mColorTransitions.size() > 0 && "to use this operator, you must define some colors" );
         float range = (float)mColorTransitions.size() - 1.0f; 

         // the indices of the two colors to interpolate between 
         float indexf = age__zero_to_one * range;
         int index = (int)indexf;
         int next_index = (index+1 != (int)mColorTransitions.size()) ? index+1 : (mColorTransitions.size() - 1);
         assert( index >= 0 && next_index < (int)mColorTransitions.size() && "out of bounds" );

         // find the value to interpolate this color with the next color (should be 0..1)
         float val = indexf - (float)index;

         gmtl::Vec4f color;
         gmtl::lerp( color, val, mColorTransitions[index], mColorTransitions[next_index] );

         //color.setHSV( rel, 0.8f, 1.0f );
         p->setColor( color );
      }
   }
} // end namespace

#endif

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