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/** \author Jia Pan */

#include "fcl/BV/AABB.h"

#include <limits>
#include <iostream>

namespace fcl
{

AABB::AABB() : min_(std::numeric_limits<FCL_REAL>::max()),
               max_(-std::numeric_limits<FCL_REAL>::max())
{
}

FCL_REAL AABB::distance(const AABB& other, Vec3f* P, Vec3f* Q) const
{
  FCL_REAL result = 0;
  for(std::size_t i = 0; i < 3; ++i)
  {
    const FCL_REAL& amin = min_[i];
    const FCL_REAL& amax = max_[i];
    const FCL_REAL& bmin = other.min_[i];
    const FCL_REAL& bmax = other.max_[i];
    
    if(amin > bmax)
    {
      FCL_REAL delta = bmax - amin;
      result += delta * delta;
      if(P && Q)
      {
        (*P)[i] = amin;
        (*Q)[i] = bmax;
      }
    }
    else if(bmin > amax)
    {
      FCL_REAL delta = amax - bmin;
      result += delta * delta;
      if(P && Q)
      {
        (*P)[i] = amax;
        (*Q)[i] = bmin;
      }
    }
    else
    {
      if(P && Q)
      {
        if(bmin >= amin)
        {
          FCL_REAL t = 0.5 * (amax + bmin);
          (*P)[i] = t;
          (*Q)[i] = t;
        }
        else
        {
          FCL_REAL t = 0.5 * (amin + bmax);
          (*P)[i] = t;
          (*Q)[i] = t;
        }
      }
    }
  }

  return std::sqrt(result);
}

FCL_REAL AABB::distance(const AABB& other) const
{
  FCL_REAL result = 0;
  for(std::size_t i = 0; i < 3; ++i)
  {
    const FCL_REAL& amin = min_[i];
    const FCL_REAL& amax = max_[i];
    const FCL_REAL& bmin = other.min_[i];
    const FCL_REAL& bmax = other.max_[i];
    
    if(amin > bmax)
    {
      FCL_REAL delta = bmax - amin;
      result += delta * delta;
    }
    else if(bmin > amax)
    {
      FCL_REAL delta = amax - bmin;
      result += delta * delta;
    }
  }

  return std::sqrt(result);
}

}
