New cpp folder structure

Signed-off-by: Alexander Borsuk <me@alex.bio>

libs/geometry/triangle2d.hpp

@@ -0,0 +1,66 @@
+#pragma once
+
+#include "point2d.hpp"
+
+#include <sstream>
+#include <vector>
+
+namespace m2
+{
+
+template <typename T> struct Triangle
+{
+  Point<T> m_points[3];
+
+  Triangle(Point<T> const & p1, Point<T> const & p2, Point<T> const & p3)
+  {
+    m_points[0] = p1;
+    m_points[1] = p2;
+    m_points[2] = p3;
+  }
+
+  Point<T> const & p1() const { return m_points[0]; }
+  Point<T> const & p2() const { return m_points[1]; }
+  Point<T> const & p3() const { return m_points[2]; }
+};
+
+using TriangleF = Triangle<float>;
+using TriangleD = Triangle<double>;
+
+template <typename T>
+std::string DebugPrint(m2::Triangle<T> const & trg)
+{
+  std::stringstream s;
+  s << "Triangle ["
+    << DebugPrint(trg.p1()) << ", "
+    << DebugPrint(trg.p2()) << ", "
+    << DebugPrint(trg.p3()) << "]";
+  return s.str();
+}
+
+template <class T>
+double GetTriangleArea(Point<T> const & p1, Point<T> const & p2, Point<T> const & p3)
+{
+  return 0.5 * fabs((p2.x - p1.x)*(p3.y - p1.y) - (p3.x - p1.x)*(p2.y - p1.y));
+}
+
+m2::PointD GetRandomPointInsideTriangle(m2::TriangleD const & t);
+m2::PointD GetRandomPointInsideTriangles(std::vector<m2::TriangleD> const & v);
+
+// Project point to the nearest edge of the nearest triangle from list of triangles.
+// pt must be outside triangles.
+m2::PointD ProjectPointToTriangles(m2::PointD const & pt, std::vector<m2::TriangleD> const & v);
+
+/// @param[in] pt - Point to check
+/// @param[in] p1, p2, p3 - Triangle
+//@{
+bool IsPointInsideTriangle(m2::PointD const & pt, m2::PointD const & p1,
+                           m2::PointD const & p2, m2::PointD const & p3);
+
+bool IsPointStrictlyInsideTriangle(m2::PointD const & pt, m2::PointD const & p1,
+                                   m2::PointD const & p2, m2::PointD const & p3);
+
+bool IsPointInsideTriangles(m2::PointD const & pt, std::vector<m2::TriangleD> const & v);
+//@}
+
+} // namespace m2