bug fix for the corrected output of 2D Convex Hulls

git-svn-id: svn+ssh://svn.pointclouds.org/pcl/trunk@8279 a9d63959-f2ad-4865-b262-bf0e56cfafb6

segmentation/include/pcl/segmentation/impl/extract_polygonal_prism_data.hpp

@@ -138,6 +138,30 @@ pcl::isXYPointIn2DXYPolygon (const PointT &point, const pcl::PointCloud<PointT>
     xold = xnew;
     yold = ynew;
   }
+
+  // And a last check for the polygon line formed by the last and the first points
+  double xnew = polygon.points[0].x;
+  double ynew = polygon.points[0].y;
+  if (xnew > xold)
+  {
+    x1 = xold;
+    x2 = xnew;
+    y1 = yold;
+    y2 = ynew;
+  }
+  else
+  {
+    x1 = xnew;
+    x2 = xold;
+    y1 = ynew;
+    y2 = yold;
+  }
+
+  if ( (xnew < point.x) == (point.x <= xold) && (point.y - y1) * (x2 - x1) < (y2 - y1) * (point.x - x1) )
+  {
+    in_poly = !in_poly;
+  }
+
   return (in_poly);
 }