rewrote BoundaryElementsAlongPolyline which works independently from node order of edges

MeshGeoToolsLib/BoundaryElementsAlongPolyline.cpp

@@ -13,7 +13,9 @@
 #include "GeoLib/Polyline.h"
 
 #include "MeshLib/Mesh.h"
+#include "MeshLib/Node.h"
 #include "MeshLib/Elements/Element.h"
+#include "MeshLib/Elements/Line.h"
 #include "MeshLib/MeshSearcher.h"
 
 #include "MeshGeoToolsLib/MeshNodeSearcher.h"
@@ -24,21 +26,13 @@ namespace MeshGeoToolsLib
 BoundaryElementsAlongPolyline::BoundaryElementsAlongPolyline(MeshLib::Mesh const& mesh, MeshNodeSearcher &mshNodeSearcher, GeoLib::Polyline const& ply)
 : _mesh(mesh), _ply(ply)
 {
-	// search nodes located along the polyline
+	// search nodes and elements located along the polyline
 	auto node_ids_on_poly = mshNodeSearcher.getMeshNodeIDsAlongPolyline(ply);
-	std::vector<std::size_t> work_node_ids(node_ids_on_poly);
-	if (ply.isClosed())
-		work_node_ids.push_back(work_node_ids[0]);
+	auto ele_ids_near_ply = MeshLib::getConnectedElementIDs(_mesh, node_ids_on_poly);
 
-	// search edges
-	for (unsigned i=0; i<work_node_ids.size()-1; i++) {
-		std::vector<std::size_t> edge_nodeIDs = {work_node_ids[i], work_node_ids[i+1]};
-		// find a shared element
-		auto* node1 = mesh.getNode(edge_nodeIDs[0]);
-		auto* node2 = mesh.getNode(edge_nodeIDs[1]);
-		auto it = std::find_first_of(node1->getElements().begin(), node1->getElements().end(), node2->getElements().begin(), node2->getElements().end());
-		assert (it!=node1->getElements().end());
-		auto* e = *it;
+	// check all edges of the elements near the polyline
+	for (auto ele_id : ele_ids_near_ply) {
+		auto* e = _mesh.getElement(ele_id);
 		// skip internal elements
 		bool isOuterElement = false;
 		for (unsigned i=0; i<e->getNNeighbors(); i++) {
@@ -49,24 +43,47 @@ BoundaryElementsAlongPolyline::BoundaryElementsAlongPolyline(MeshLib::Mesh const
 		}
 		if (!isOuterElement)
 			continue;
-		// find edges on polyline
+		// find edges on the polyline
 		for (unsigned i=0; i<e->getNEdges(); i++) {
 			auto* edge = e->getEdge(i);
-			// check
-			size_t cnt_match = 0;
+			// check if an edge node is on the polyline (if yes, store a distance)
+			std::vector<std::size_t> vec_matched_node_distance_along_ply;
 			for (size_t j=0; j<edge->getNNodes(); j++) {
-				if (std::find(edge_nodeIDs.begin(), edge_nodeIDs.end(), edge->getNodeIndex(j)) != edge_nodeIDs.end())
-					cnt_match++;
+				auto itr = std::find(node_ids_on_poly.begin(), node_ids_on_poly.end(), edge->getNodeIndex(j));
+				if (itr != node_ids_on_poly.end())
+					vec_matched_node_distance_along_ply.push_back(std::distance(node_ids_on_poly.begin(), itr));
 				else
 					break;
 			}
-			// update the list
-			if (cnt_match==edge->getNNodes()) {
-				_boundary_elements.push_back(const_cast<MeshLib::Element*>(edge));
-				break;
+			// the edge is picked if its all nodes are on the polyline
+			if (vec_matched_node_distance_along_ply.size()==edge->getNNodes()) {
+				MeshLib::Element* picked_ele = const_cast<MeshLib::Element*>(edge);
+				// The first node of the edge should be always closer to the beginning of the polyline than other nodes.
+				// Otherwise, create a new element with reversed local node index
+				if (vec_matched_node_distance_along_ply.front() > vec_matched_node_distance_along_ply.back()
+						|| (ply.isClosed() && vec_matched_node_distance_along_ply.back() == node_ids_on_poly.size()-1)) {
+					MeshLib::Node** new_nodes = new MeshLib::Node*[edge->getNNodes()];
+					std::reverse_copy(edge->getNodes(), edge->getNodes()+edge->getNNodes(), new_nodes);
+					picked_ele = new MeshLib::Line(new_nodes);
+					delete edge;
+				}
+				_boundary_elements.push_back(picked_ele);
+			} else {
+				delete edge;
 			}
 		}
 	}
+
+	// sort picked edges according to a distance of their first node along the polyline
+	std::sort(_boundary_elements.begin(), _boundary_elements.end(),
+			[&](MeshLib::Element*e1, MeshLib::Element*e2)
+			{
+				std::size_t dist1 = std::distance(node_ids_on_poly.begin(),
+					std::find(node_ids_on_poly.begin(), node_ids_on_poly.end(), e1->getNodeIndex(0)));
+				std::size_t dist2 = std::distance(node_ids_on_poly.begin(),
+					std::find(node_ids_on_poly.begin(), node_ids_on_poly.end(), e2->getNodeIndex(0)));
+				return (dist1 < dist2);
+			});
 }
 
 BoundaryElementsAlongPolyline::~BoundaryElementsAlongPolyline()