Introduce QuadMesh

lib/happah/geometry/QuadMesh.hpp

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+// Copyright 2015 - 2017
+//   Pawel Herman - Karlsruhe Institute of Technology - pherman@ira.uka.de
+//   Hedwig Amberg  - Karlsruhe Institute of Technology - hedwigdorothea@gmail.com
+// Distributed under the Boost Software License, Version 1.0.
+// (See accompanying file LICENSE or copy at http://www.boost.org/LICENSE_1_0.txt)
+
+// 2017.11 - Hedwig Amberg    - Introduce QuadMesh.
+
+#pragma once
+
+#include "happah/geometry/TriangleMesh.hpp"
+
+namespace happah {
+
+//DECLARATIONS
+
+template<class Vertex>
+class QuadMesh;
+
+template<class Vertex>
+QuadMesh<Vertex> make_quad_mesh(std::vector<Vertex> vertices, Indices indices);
+
+//Convert a string representation in HPH format.
+template<class Vertex = VertexP3>
+QuadMesh<Vertex> make_quad_mesh(const std::string& mesh);
+
+//Import data stored in the given file in HPH format.
+template<class Vertex = VertexP3>
+QuadMesh<Vertex> make_quad_mesh(const std::experimental::filesystem::path& mesh);
+
+template<class Vertex = VertexP3>
+TriangleMesh<Vertex> make_triangle_mesh(const QuadMesh<Vertex>&  mesh);
+
+template<class Vertex>
+hpuint size(const QuadMesh<Vertex>& mesh);
+
+//DEFINITIONS
+
+template<class Vertex>
+class QuadMesh {
+public:
+     QuadMesh() {}
+
+     //NOTE: Indices all have to be arranged counterclockwise.
+     QuadMesh(std::vector<Vertex> vertices, Indices indices)
+          : m_indices(std::move(indices)), m_vertices(std::move(vertices)) {}
+
+     const Indices& getIndices() const { return m_indices; }
+
+     Indices& getIndices() { return m_indices; }
+
+     hpuint getNumberOfRectangles() const { return m_indices.size() / 4; }
+
+     hpuint getNumberOfVertices() const { return m_vertices.size(); }//TODO: number of vertices on mesh may be less than the number of vertices in vector
+
+     std::tuple<const Vertex&, const Vertex&, const Vertex&> getRectangle(hpuint t) const { return std::tie(getVertex(t, 0), getVertex(t, 1), getVertex(t, 2), getVertex(t, 3)); }
+
+     auto& getVertex(hpindex v) const { return m_vertices[v]; }
+
+     auto& getVertex(hpindex v) { return m_vertices[v]; }
+
+     auto& getVertex(hpindex t, hpindex i) const { return m_vertices[m_indices[4 * t + i]]; }
+
+     auto& getVertices() const { return m_vertices; }
+
+     auto& getVertices() { return m_vertices; }
+
+private:
+     Indices m_indices;
+     std::vector<Vertex> m_vertices;
+
+};//QuadMesh
+
+template<class Vertex>
+QuadMesh<Vertex> make_quad_mesh(std::vector<Vertex> vertices, Indices indices) { return { std::move(vertices), std::move(indices) }; }
+
+template<class Vertex>
+QuadMesh<Vertex> make_quad_mesh(const std::string& mesh) { return format::hph::read<QuadMesh<Vertex> >(mesh); }
+
+template<class Vertex>
+QuadMesh<Vertex> make_quad_mesh(const std::experimental::filesystem::path& mesh) { return format::hph::read<QuadMesh<Vertex> >(mesh); }
+
+template<class Vertex = VertexP3>
+TriangleMesh<Vertex> make_triangle_mesh(const QuadMesh<Vertex>&  mesh){
+     auto q_indices = mesh.getIndices();
+     auto indices = Indices();
+     auto vertices = mesh.getVertices();
+     for(hpuint i = 0; i < size(q_indices); ++i){
+          auto i0 = q_indices[i];
+          auto i1 = q_indices[++i];
+          auto i2 = q_indices[++i];
+          auto i3 = q_indices[++i];
+          indices.push_back(i0);
+          indices.push_back(i1);
+          indices.push_back(i2);
+          indices.push_back(i0);
+          indices.push_back(i2);
+          indices.push_back(i3);
+     }
+     return make_triangle_mesh(std::move(vertices), std::move(indices));
+}
+
+template<class Vertex>
+hpuint size(const QuadMesh<Vertex>& mesh) { return mesh.getNumberOfRectangles(); }
+
+}//namespace happah