SearchGridT.h

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/*
   For more information, please see: http://software.sci.utah.edu

   The MIT License

   Copyright (c) 2009 Scientific Computing and Imaging Institute,
   University of Utah.

   
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/// @todo Documentation Core/GeometryPrimitives/SearchGridT.h

#ifndef CORE_DATATYPES_SEARCHGRIDT_H
#define CORE_DATATYPES_SEARCHGRIDT_H 1

#include <Core/GeometryPrimitives/Point.h>
#include <Core/GeometryPrimitives/BBox.h>
#include <Core/GeometryPrimitives/Transform.h>
#include <Core/Datatypes/Legacy/Base/Types.h>

#include <algorithm>
#include <vector>

#include <Core/GeometryPrimitives/share.h>

namespace SCIRun {

template<class INDEX>
class SearchGridT 
{
  public:
    /// Include the types defined in Types into this class
    typedef SCIRun::index_type                    index_type;
    typedef SCIRun::size_type                     size_type;
    typedef typename std::vector<INDEX>::iterator iterator;

    SearchGridT(size_type x, size_type y, size_type z,
               const Core::Geometry::Point &min, const Core::Geometry::Point &max) :
        ni_(x), nj_(y), nk_(z)
      {
        transform_.pre_scale(Core::Geometry::Vector(1.0 / x, 1.0 / y, 1.0 / z));
        transform_.pre_scale(max - min);

        transform_.pre_translate(Core::Geometry::Vector(min));
        transform_.compute_imat();
        bin_.resize(x*y*z);
      }

    inline void transform(const Core::Geometry::Transform &t) 
      { transform_.pre_trans(t);}

    inline const Core::Geometry::Transform &get_transform() const 
      { return transform_; }
      
    inline Core::Geometry::Transform &set_transform(const Core::Geometry::Transform &trans) 
      { transform_ = trans; return transform_; }
  

    /// Get the size of the search grid
    inline size_type get_ni() const { return ni_; }
    inline size_type get_nj() const { return nj_; }
    inline size_type get_nk() const { return nk_; }

    inline bool locate(index_type &i, index_type &j, 
                       index_type &k, const Core::Geometry::Point &p) const
    {
      const Core::Geometry::Point r = transform_.unproject(p);
      
      const double rx = floor(r.x());
      const double ry = floor(r.y());
      const double rz = floor(r.z());

      // Clamp in double space to avoid overflow errors.
      if (rx < 0.0      || ry < 0.0      || rz < 0.0    ||
          rx >= ni_     || ry >= nj_     || rz >= nk_   )
      {
        return (false);
      }

      i = static_cast<index_type>(rx);
      j = static_cast<index_type>(ry);
      k = static_cast<index_type>(rz);
      return (true);
    }


    inline bool locate_clamp(index_type &i, index_type &j, 
                       index_type &k, const Core::Geometry::Point &p) const
    {
      const Core::Geometry::Point r = transform_.unproject(p);
      
      double rx = floor(r.x());
      double ry = floor(r.y());
      double rz = floor(r.z());

      // Clamp in double space to avoid overflow errors.
      if (rx < 0.0) rx = 0.0;
      if (ry < 0.0) ry = 0.0;
      if (rz < 0.0) rz = 0.0;

      if (rx >= ni_) rx = ni_;
      if (ry >= nj_) ry = nj_;
      if (rz >= nk_) rz = nk_;

      i = static_cast<index_type>(rx);
      j = static_cast<index_type>(ry);
      k = static_cast<index_type>(rz);
      return (true);
    }
                                                  
    inline void unsafe_locate(index_type &i, index_type &j, 
                              index_type &k, const Core::Geometry::Point &p) const
    {
      Core::Geometry::Point r;
      transform_.unproject(p, r);
      
      i = static_cast<index_type>(r.x());
      j = static_cast<index_type>(r.y());
      k = static_cast<index_type>(r.z());
    }
  
    void insert(INDEX val, const Core::Geometry::BBox &bbox)
    {
      index_type mini=0, minj=0, mink=0, maxi=0, maxj=0, maxk=0;

      locate(mini, minj, mink, bbox.min());
      locate(maxi, maxj, maxk, bbox.max());
      
      for (index_type i = mini; i <= maxi; i++)
      {
        for (index_type j = minj; j <= maxj; j++)
        {
          for (index_type k = mink; k <= maxk; k++)
          {
            bin_[linearize(i, j, k)].push_back(val);
          }
        }
      }
    }   

    void remove(INDEX val, const Core::Geometry::BBox &bbox)
    {
      index_type mini, minj, mink, maxi, maxj, maxk;

      unsafe_locate(mini, minj, mink, bbox.min());
      unsafe_locate(maxi, maxj, maxk, bbox.max());

      for (index_type i = mini; i <= maxi; i++)
      {
        for (index_type j = minj; j <= maxj; j++)
        {
          for (index_type k = mink; k <= maxk; k++)
          {
            index_type q = linearize(i, j, k);
            std::remove(bin_[q].begin(),bin_[q].end(),val);
          }
        }
      }
    }

    void insert(INDEX val, const Core::Geometry::Point &point)
    {
      index_type i, j, k;
      unsafe_locate(i, j, k, point);
      bin_[linearize(i, j, k)].push_back(val);
    }  

    void remove(INDEX val, const Core::Geometry::Point &point)
    {
      index_type i, j, k;
      unsafe_locate(i, j, k, point);
      index_type q = linearize(i, j, k);
      std::remove(bin_[q].begin(),bin_[q].end(),val);
    }
    
    inline bool lookup(iterator &begin, iterator &end, const Core::Geometry::Point &p)
    {
      index_type i, j, k;
      if (locate(i, j, k, p))
      {
        index_type q = linearize(i, j, k);
        begin = bin_[q].begin();
        end   = bin_[q].end();
        return (true);
      }
      return (false);    
    }
    
    inline void lookup_ijk(iterator &begin, iterator &end, size_type i, size_type j, 
                    size_type k)
    {
      index_type q = linearize(i, j, k);
      begin = bin_[q].begin();
      end   = bin_[q].end();    
    }                
                      
    
    double min_distance_squared(const Core::Geometry::Point &p, size_type i, 
                              size_type j, size_type k) const
    {
      Core::Geometry::Point r;
      transform_.unproject(p, r);

      // Splat the point onto the cell.
      if (r.x() < i) { r.x(i); }
      else if (r.x() > i+1) { r.x(i+1); }

      if (r.y() < j) { r.y(j); }
      else if (r.y() > j+1) { r.y(j+1); }

      if (r.z() < k) { r.z(k); }
      else if (r.z() > k+1) { r.z(k+1); }
      
      // Project the cell intersection back to world space.
      Core::Geometry::Point q;
      transform_.project(r, q);
      
      // Return distance from point to projected cell point.
      return (p - q).length2();
    }
  
  private:
    index_type linearize(index_type i, index_type j, index_type k) const
      { return (((i * nj_) + j) * nk_ + k); }


  private:
    /// Size of the search grid
    index_type ni_, nj_, nk_;
    /// Transformation to unitary coordinate system
    Core::Geometry::Transform transform_;
    
    /// Where to store the lookup table
    std::vector<std::vector<INDEX> > bin_;   
};


} // namespace SCIRun

#endif