Question

I have been told if you have a reference in a class you have to create new versions of that class rather than copy them around. Why? Because you are actually referring to the original thing when you assign a reference and so you’re not actually doing anything. The thing is, why does it still work?

My GameObjects contain references to Meshes, and I can copy them around fine and they all render in the right places and everything.

Answer 1

The copy constructor is initialising a new reference, which is fine.

What you can’t do is reassign the reference later.

Here’s an example, assuming your class can be constructed by supplying a Mesh, to which it retains a reference:

Mesh mesh;
GameObject o1(mesh);      // OK: initialising reference o1.mesh
GameObject o2(o1);        // OK: initialising reference o2.mesh
o1 = o2;                  // Error: attempt to reassign reference o1.mesh

(That’s assuming you don’t define a copy-assignment operator. If you do, then it will have to leave the reference alone.)