Implemented: check for problematic arc in Antarctica (looks like it is repeating 2 points in the south pole so that they can be seen in the projected planar coordinates when the coordinates are wrapped along the x-axis (longitude)

Arrangement_on_surface_2/demo/earth/Kml_reader.cpp

@@ -206,3 +206,67 @@ Kml::Nodes Kml::get_duplicates(const Placemarks& placemarks)
 
   return duplicate_nodes;
 }
+
+Kml::Nodes Kml::Polygon::get_all_nodes() const
+{
+  Nodes all_nodes;
+  auto source_first = outer_boundary.nodes.begin();
+  auto source_last = outer_boundary.nodes.end();
+  all_nodes.insert(all_nodes.begin(), source_first, source_last);
+
+  for (const auto& inner_boundary : inner_boundaries)
+  {
+    auto source_first = inner_boundary.nodes.begin();
+    auto source_last = inner_boundary.nodes.end();
+    all_nodes.insert(all_nodes.begin(), source_first, source_last);
+  }
+
+  return all_nodes;
+}
+
+Kml::Nodes Kml::Placemark::get_all_nodes() const
+{
+  Nodes all_nodes;
+  for (const auto& polygon : polygons)
+  {
+    auto polygon_nodes = polygon.get_all_nodes();
+    auto first = std::make_move_iterator(polygon_nodes.begin());
+    auto last = std::make_move_iterator(polygon_nodes.end());
+    all_nodes.insert(all_nodes.end(), first, last);
+  }
+
+  return all_nodes;
+}
+
+Kml::Arcs Kml::LinearRing::get_arcs() const
+{
+  Arcs arcs;
+  const int num_nodes = nodes.size();
+  for (int i = 0; i < num_nodes - 1; ++i)
+  {
+    const auto from = nodes[i];
+    const auto to = nodes[i + 1];
+    arcs.push_back(Arc{ from, to });
+  }
+  return arcs;
+}
+void Kml::LinearRing::get_arcs(Arcs& arcs) const
+{
+  auto a = get_arcs();
+  arcs.insert(arcs.end(), a.begin(), a.end());
+}
+
+Kml::Arcs Kml::Placemark::get_all_arcs() const
+{
+  Arcs all_arcs;
+
+  for (const auto& polygon : polygons)
+  {
+    polygon.outer_boundary.get_arcs(all_arcs);
+    for (const auto& inner_boundary : polygon.inner_boundaries)
+      inner_boundary.get_arcs(all_arcs);
+  }
+
+  return all_arcs;
+}
+

Arrangement_on_surface_2/demo/earth/Kml_reader.h

@@ -2,6 +2,7 @@
 #ifndef KML_READER_H
 #define KML_READER_H
 
+#include <iostream>
 #include <string>
 #include <vector>
 
@@ -24,11 +25,26 @@ public:
     bool operator == (const Node& r) const;
     Vec3d get_coords_3d(const double r = 1.0) const;
     QVector3D get_coords_3f(const double r=1.0) const;
+    friend std::ostream& operator << (std::ostream& os, const Node& n)
+    {
+      os << n.lon << ", " << n.lat;
+      return os;
+    }
   };
+  using Nodes = std::vector<Node>;
+
+  struct Arc
+  {
+    Node from, to;
+  };
+  using Arcs = std::vector<Arc>;
 
   struct LinearRing
   {
     std::vector<Node> nodes;
+
+    Arcs get_arcs() const;
+    void get_arcs(Arcs& arcs) const;
   };
   using LinearRings = std::vector<LinearRing>;
 
@@ -37,15 +53,23 @@ public:
   {
     LinearRing outer_boundary;
     LinearRings inner_boundaries;
+
+    // when collecting nodes start from the outer boundary and then get nodes
+    // from individual inner boundaries in the order
+    Nodes get_all_nodes() const;
   };
  
+
   struct Placemark
   {
     std::vector<Polygon> polygons;
     std::string name;
-  };
 
-  using Nodes = std::vector<Node>;
+    // collects all nodes from all polygons
+    Nodes get_all_nodes() const;
+
+    Arcs get_all_arcs() const;
+  };
   using Placemarks = std::vector<Placemark>;
 
 

Arrangement_on_surface_2/demo/earth/Main_widget.cpp

@@ -113,41 +113,60 @@ void Main_widget::keyPressEvent(QKeyEvent* event)
   {
   case Qt::Key_Q:
   {
-    auto num_arcs = m_country_borders[m_selected_country]->get_num_line_strips();
-    if (++m_selected_arc == num_arcs)
-      m_selected_arc--;
-    std::cout << "selected arc = " << m_selected_arc << std::endl;
+    auto num_arcs = m_country_borders[m_selected_country_index]->get_num_line_strips();
+    if (++m_selected_arc_index == num_arcs)
+      m_selected_arc_index--;
+    qDebug() << "---------------------------------------";
+    qDebug() << "selected arc index = " << m_selected_arc_index;
+    
+    const auto& arc = m_selected_country_arcs[m_selected_arc_index];
+    std::cout << arc.from << "  TO  " << arc.to << std::endl;
   }
     break;
   case Qt::Key_A:
   {
-    auto num_arcs = m_country_borders[m_selected_country]->get_num_line_strips();
-    if (--m_selected_arc < 0)
-      m_selected_arc = 0;
-    std::cout << "selected arc = " << m_selected_arc << std::endl;
+    auto num_arcs = m_country_borders[m_selected_country_index]->get_num_line_strips();
+    if (--m_selected_arc_index < 0)
+      m_selected_arc_index = 0;
+    std::cout << "selected arc = " << m_selected_arc_index << std::endl;
   }
     break;
 
   case Qt::Key_Up:
-    m_selected_country++;
-    if (m_selected_country == m_country_names.size())
-      m_selected_country--;
-    std::cout << m_selected_country << ": " << m_country_names[m_selected_country] << std::endl;
-    m_selected_arc = 0;
+    m_selected_country_index++;
+    if (m_selected_country_index == m_country_names.size())
+      m_selected_country_index--;
+    std::cout << m_selected_country_index << ": " 
+              << m_country_names[m_selected_country_index] << std::endl;
+    
+    m_selected_arc_index = 0;
+    m_selected_country = &m_countries[m_selected_country_index];
+    m_selected_country_nodes = m_selected_country->get_all_nodes();
+    m_selected_country_arcs = m_selected_country->get_all_arcs();
+
+    {
+      auto num_arcs = m_country_borders[m_selected_country_index]->get_num_line_strips();
+      
+      qDebug() << "num KML arcs = " << m_selected_country_arcs.size();
+      qDebug() << "num arcs = " << num_arcs;
+    }
     break;
 
   case Qt::Key_Down:
-    m_selected_country--;
-    if (m_selected_country < 0)
-      m_selected_country = 0;
-    std::cout << m_selected_country << ": " << m_country_names[m_selected_country] << std::endl;
-    m_selected_arc = 0;
+    m_selected_country_index--;
+    if (m_selected_country_index < 0)
+      m_selected_country_index = 0;
+    std::cout << m_selected_country_index << ": " 
+              << m_country_names[m_selected_country_index] << std::endl;
+    
+    m_selected_arc_index = 0;
+    m_selected_country = &m_countries[m_selected_country_index];
+    m_selected_country_nodes = m_selected_country->get_all_nodes();
     break;
-
-
   }
 }
 
+
 #include <shapefil.h>
 
 void readShapefile(const std::string& filename) {
@@ -191,11 +210,11 @@ void Main_widget::initializeGL()
 
   //const auto file_name = "C:/work/gsoc2023/data/world_countries.kml";
   const auto file_name = "C:/work/gsoc2023/data/ne_110m_admin_0_countries.kml";
-  auto countries = Kml::read(file_name);
-  auto dup_nodes = Kml::get_duplicates(countries);
+  m_countries = Kml::read(file_name);
+  auto dup_nodes = Kml::get_duplicates(m_countries);
   
   // initialize rendering of DUPLICATE VERTICES
-  if(0)
+  if(1)
   {
     std::vector<QVector3D> vertices;
     for (const auto& node : dup_nodes)
@@ -206,7 +225,7 @@ void Main_widget::initializeGL()
   else
   {
     // check the arrangement constructed from the GIS data-set
-    auto created_vertices = Aos::ext_check(countries);
+    auto created_vertices = Aos::ext_check(m_countries);
     m_vertices = std::make_unique<Vertices>(created_vertices);
   }
 
@@ -226,15 +245,18 @@ void Main_widget::initializeGL()
     //auto lsa = Aos::get_approx_arcs(countries, error);
     //auto lsa = Aos::get_approx_arcs(error);
     //m_geodesic_arcs = std::make_unique<Line_strips>(lsa);
-    for (const auto& country : countries)
+    for (const auto& country : m_countries)
     {
       m_country_names.push_back(country.name);
       auto approx_arcs = Aos::get_approx_arcs(country, error);
       auto country_border = std::make_unique<Line_strips>(approx_arcs);
       m_country_borders.push_back(std::move(country_border));
     }
-    m_selected_country = 25;
-    m_selected_arc = 0;
+    m_selected_country_index = 159; // ANTARCTICA
+    m_selected_country = &m_countries[m_selected_country_index];
+    m_selected_country_nodes = m_selected_country->get_all_nodes();
+    m_selected_country_arcs = m_selected_country->get_all_arcs();
+    m_selected_arc_index = 0;
   }
 
   glClearColor(0, 0, 0, 1);
@@ -459,13 +481,19 @@ void Main_widget::paintGL()
     for(auto& country_border : m_country_borders)
       country_border->draw();
 
-    sp.set_uniform("u_color", arc_color);
-      m_country_borders[m_selected_country]->draw(m_selected_arc);
+    // draw the selected country in blue color
+    auto& selected_countru = m_country_borders[m_selected_country_index];
+    sp.set_uniform("u_color", QVector4D(0, .6, 1, 1));
+    selected_countru->draw();
+
+    // draw the current arc of the selected country in YELLOW
+    sp.set_uniform("u_color", QVector4D(1, 1, 0, 1));
+    selected_countru->draw(m_selected_arc_index);
 
     const QVector4D vertex_color(1, 0, 0, 1);
     sp.set_uniform("u_color", vertex_color);
     glPointSize(5);
-    m_vertices->draw();
+    //m_vertices->draw();
 
     sp.unuse();
   }

Arrangement_on_surface_2/demo/earth/Main_widget.h

@@ -10,12 +10,14 @@
 #include <QVector2D>
 #include <QBasicTimer>
 
+#include <functional>
 #include <memory>
 
 #include <qopenglwidget.h>
 
 #include "Camera.h"
 #include "Common_defs.h"
+#include "Kml_reader.h"
 #include "Line_strips.h"
 #include "Shader_program.h"
 #include "Sphere.h"
@@ -60,11 +62,19 @@ private:
   std::unique_ptr<Line_strips>      m_geodesic_arcs;
   std::unique_ptr<Vertices>         m_vertices;
 
-  // now we draw boundary-arcs by country
-  int   m_selected_country, m_selected_arc;
+  // COUNTRY DATA
+  Kml::Placemarks                             m_countries;
   std::vector<std::string>                    m_country_names;
   std::vector<std::unique_ptr<Line_strips>>   m_country_borders;
 
+  // now we draw boundary-arcs by country
+  int             m_selected_country_index, m_selected_arc_index;
+  Kml::Nodes      m_selected_country_nodes;
+  Kml::Arcs       m_selected_country_arcs;
+  Kml::Placemark* m_selected_country;
+ 
+
+
   // Shaders
   Shader_program  m_sp_smooth;
   Shader_program  m_sp_per_vertex_color;