MarkNodesOutsideOfPolygon.h

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// SPDX-FileCopyrightText: Copyright (c) OpenGeoSys Community (opengeosys.org)
// SPDX-License-Identifier: BSD-3-Clause
 
#pragma once
 
#include <algorithm>
#include <vector>
 
#include "GeoLib/AnalyticalGeometry.h"
#include "GeoLib/Polygon.h"
 
#include "MeshLib/Node.h"
 
namespace MeshGeoToolsLib
{
std::vector<bool> markNodesOutSideOfPolygon(
    std::vector<MeshLib::Node*> const& nodes, GeoLib::Polygon const& polygon)
{
    // *** rotate polygon points to xy-plane
    auto [rotated_polygon_points, normal] =
        GeoLib::rotatePolygonPointsToXY(polygon);
 
    // *** rotate mesh nodes to xy-plane
    // 1 copy all mesh nodes to GeoLib::Points
    std::vector<GeoLib::Point*> rotated_nodes;
    for (auto node : nodes)
    {
        rotated_nodes.push_back(new GeoLib::Point(*node, node->getID()));
    }
    // 2 rotate the Points
    Eigen::Matrix3d const rot_mat = GeoLib::computeRotationMatrixToXY(normal);
    GeoLib::rotatePoints(rot_mat, rotated_nodes);
    // 3 set z coord to zero
    std::for_each(rotated_nodes.begin(), rotated_nodes.end(),
                  [](GeoLib::Point* p) { (*p)[2] = 0.0; });
 
    std::vector<bool> outside(rotated_nodes.size(), true);
    // *** mark rotated nodes inside rotated polygon
    {
        // create new polygon using the rotated points
        GeoLib::Polyline rotated_polyline(rotated_polygon_points);
        for (std::size_t k(0); k < polygon.getNumberOfPoints(); k++)
        {
            rotated_polyline.addPoint(k);
        }
        rotated_polyline.addPoint(0);
        GeoLib::Polygon const rotated_polygon(rotated_polyline);
 
        for (std::size_t k(0); k < rotated_nodes.size(); k++)
        {
            if (rotated_polygon.isPntInPolygon(*(rotated_nodes[k])))
            {
                outside[k] = false;
            }
        }
    }
 
    for (auto& rotated_node : rotated_nodes)
    {
        delete rotated_node;
    }
 
    for (auto& rot_polygon_pnt : rotated_polygon_points)
    {
        delete rot_polygon_pnt;
    }
 
    return outside;
}
 
}  // end namespace MeshGeoToolsLib