partial reload from json working, but edges make problems

src/vmath.h

@@ -2,6 +2,7 @@
 
 #include "raylib.h"
 #include <cmath>
+#include <iostream>
 
 #include "nlohmann/json.hpp"
 
@@ -107,12 +108,13 @@ namespace VISEQ::VMATH{
 	};
 
 	template<typename T>
-	void to_json(json& j, const Vec2D<T> V){
+	void to_json(json& j, const Vec2D<T>& V){
 		j = json{{"x",V.x},{"y",V.y}};
 	}
 	
 	template<typename T>
-	void from_json(const json& j, Vec2D<T> V){
+	void from_json(const json& j, Vec2D<T>& V){
+		std::cout << "Vec2D" << std::endl;
 		j.at("x").get_to(V.x);
 		j.at("y").get_to(V.y);
 	}