Serializable mesh with nlohmann_json

Displays a cube generated by meshlib.hpp (serialtest)

include/ml/meshlib_json.hpp

@@ -0,0 +1,72 @@
+#pragma once
+
+#include "meshlib.hpp"
+
+#include <Eigen/Eigen>
+#include <nlohmann/json.hpp>
+
+namespace Eigen {
+    template<class Derived>
+    void to_json(nlohmann::json &json, const Eigen::PlainObjectBase<Derived> &mat) {
+        using Scalar = typename Derived::Scalar;
+
+        auto rows = mat.rows();
+        auto cols = mat.cols();
+
+        std::vector<Scalar> vals(mat.size());
+        Map<Derived>(vals.data(), rows, cols) = mat;
+
+        json = {
+            {"rows", rows},
+            {"cols", cols},
+            {"vals", vals},
+        };
+    }
+
+    template<class Derived>
+    void from_json(const nlohmann::json &j, Derived &mat) {
+        using Scalar = typename Derived::Scalar;
+
+        auto rows = j["rows"].get<Eigen::Index>();
+        auto cols = j["cols"].get<Eigen::Index>();
+        auto vals = j["vals"].get<std::vector<Scalar>>();
+
+        mat = Eigen::Map<Derived>(vals.data(), rows, cols);
+    }
+}
+
+namespace ml {
+    static void to_json(nlohmann::json &json, const ml::MeshBase &mesh) {
+        json = {
+            {"points", mesh.points()},
+            {"cells",  mesh.cells()},
+        };
+    }
+
+    static void from_json(const nlohmann::json &j, ml::DynamicMesh &mesh) {
+        mesh = {
+            j["points"].get<DynamicMesh::PointsType>(),
+            j["cells"].get<DynamicMesh::CellsType>(),
+        };
+    }
+
+    void write(const ml::MeshBase &mesh, std::ostream &out) {
+        nlohmann::json json = mesh;
+        nlohmann::json::to_msgpack(json, out);
+    }
+
+    void write(const ml::MeshBase &mesh, const std::string &path) {
+        std::ofstream file(path, std::ios::out | std::ios::binary);
+        write(mesh, file);
+    }
+
+    ml::DynamicMesh read(std::istream &in) {
+        nlohmann::json json = nlohmann::json::from_msgpack(in);
+        return json.get<ml::DynamicMesh>();
+    }
+
+    ml::DynamicMesh read(const std::string &path) {
+        std::ifstream file(path, std::ios::in | std::ios::binary);
+        return read(file);
+    }
+}