comp_geometry.cpp

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#include <cpl_visual_features/comp_geometry.h>
#include <cmath>

namespace cpl_visual_features
{
bool lineSegmentIntersection2D(pcl16::PointXYZ a1, pcl16::PointXYZ a2, pcl16::PointXYZ b1, pcl16::PointXYZ b2,
                               pcl16::PointXYZ& intersection)
{
  if (!lineLineIntersection2D(a1, a2, b1, b2, intersection))
  {
    return false;
  }
  // Test if intersection is between a1 and a2
  return (pointIsBetweenOthers(intersection, a1, a2) && pointIsBetweenOthers(intersection, b1, b2));
}

bool lineLineIntersection2D(pcl16::PointXYZ a1, pcl16::PointXYZ a2, pcl16::PointXYZ b1, pcl16::PointXYZ b2,
                            pcl16::PointXYZ& intersection)
{
  float denom = (a1.x-a2.x)*(b1.y-b2.y)-(a1.y-a2.y)*(b1.x-b2.x);
  if (denom == 0) // Parrallel lines
  {
    return false;
  }
  intersection.x = ((a1.x*a2.y - a1.y*a2.x)*(b1.x-b2.x) -
                    (a1.x - a2.x)*(b1.x*b2.y - b1.y*b2.x))/denom;
  intersection.y = ((a1.x*a2.y - a1.y*a2.x)*(b1.y-b2.y) -
                    (a1.y - a2.y)*(b1.x*b2.y - b1.y*b2.x))/denom;
  return true;
}

bool pointIsBetweenOthers(pcl16::PointXYZ& pt, pcl16::PointXYZ& x1, pcl16::PointXYZ& x2)
{
  return (pt.x >= std::min(x1.x, x2.x) && pt.x <= std::max(x1.x, x2.x) &&
          pt.y >= std::min(x1.y, x2.y) && pt.y <= std::max(x1.y, x2.y));
}

double pointLineDistance2D(pcl16::PointXYZ& pt, pcl16::PointXYZ& a, pcl16::PointXYZ& b)
{
  pcl16::PointXYZ q(a.x - pt.x, a.y - pt.y, 0.0);
  pcl16::PointXYZ n(b.x - a.x, b.y - a.y, 0.0);
  double norm_n = hypot(n.x, n.y);
  n.x /= norm_n;
  n.y /= norm_n;
  double q_dot_n = q.x*n.x+q.y*n.y;
  pcl16::PointXYZ l(q.x - q_dot_n*n.x, q.y - q_dot_n*n.y, 0.0);
  return hypot(l.x, l.y);
}

};