• Both std::istream and std::ostream are actually not defined in <iostream>, despite the fact that they look similar. They're respectively defined in <istream> and <ostream>.

  You should instead include these in the implementation file and include <iosfwd> (the iostream declaration forwarding library) in the header.

• These data members should be private:

  glm::vec3 position;
  glm::vec3 normal;
  glm::vec2 texCoord;
  

  Otherwise, they will be accessible outside of the class. If they are not meant to be this way, then you should use a struct instead, which are public by default.

• If you don't need a default constructor, then leave it out. The compiler will provide one for you.

• Regarding operator==:

  Conditional operators overloads, such as operator==, should be const as they should not modify any data members:

    bool operator==(const Vertex& other) const;
  

  Its definition could also be split into multiple lines, which is easier to read than one long line:

    bool Vertex::operator==(const Vertex& other) {
        return position == other.position
            && normal == other.normal
            && texCoord == other.texCoord;
    }
  

• Both std::istream and std::ostream are actually not defined in <iostream>, despite the fact that they look similar. They're respectively defined in <istream> and <ostream>.

  You should instead include these in the implementation file and include <iosfwd> (the iostream declaration forwarding library) in the header.

• These data members should be private:

  glm::vec3 position;
  glm::vec3 normal;
  glm::vec2 texCoord;
  

  Otherwise, they will be accessible outside of the class. If they are not meant to be this way, then you should use a struct instead, which are public by default.

• If you don't need a default constructor, then leave it out. The compiler will provide one for you.

• Regarding operator==:

  Conditional operators overloads, such as operator==, should be const as they should not modify any data members:

    bool operator==(const Vertex& other) const;
  

  Its definition could also be split into multiple lines, which is easier to read than one long line:

    bool Vertex::operator==(const Vertex& other) {
        return position == other.position
            && normal == other.normal
            && texCoord == other.texCoord;
    }
  

Somewhat minor point regarding I/O:

Neither std::istream nor std::ostream are actually defined in <iostream>; they're respectively defined in <istream> and <ostream>. You can, instead, include these in the implementation file and include <iosfwd> (iostream forwarding library) in the header.

• Both std::istream and std::ostream are actually not defined in <iostream>, despite the fact that they look similar. They're respectively defined in <istream> and <ostream>.

  You should instead include these in the implementation file and include <iosfwd> (the iostream declaration forwarding library) in the header.

• These data members should be private:

  glm::vec3 position;
  glm::vec3 normal;
  glm::vec2 texCoord;
  

  Otherwise, they will be accessible outside of the class. If they are not meant to be this way, then you should use a struct instead, which are public by default.

• If you don't need a default constructor, then leave it out. The compiler will provide one for you.

• Regarding operator==:

  Conditional operators overloads, such as operator==, should be const as they should not modify any data members:

    bool operator==(const Vertex& other) const;
  

  Its definition could also be split into multiple lines, which is easier to read than one long line:

    bool Vertex::operator==(const Vertex& other) {
        return position == other.position
            && normal == other.normal
            && texCoord == other.texCoord;
    }