Question

I’ve got a class that holds a Texture2D like so:

public class TextureData
{
    public Texture2D texture;
}

When I load all of my textures, I handle it through methods like this:

public void LoadAllTextures()
{
    foreach(string s in texturesToBeLoaded)
    {
        TextureData data = new TextureData();
        LoadTexture(s, data.texture);
        // data.texture is still null.
    }
}
public void LoadTexture(string filename, Texture2D texture)
{
    texture = content.Load<Texture2D>(filename);
    // texture now holds the texture information but it doesn't
    // actually retain it when the method ends...why?
}

Am I missing something here? If I change

public void LoadTexture(string filename, Texture2D texture)

To

public void LoadTexture(string filename, out Texture2D texture)

It works fine.

---

EDIT: Alright so the way I understand it now is this…

public void LoadAllTextures()
{
    foreach(string s in texturesToBeLoaded)
    {
        TextureData data = new TextureData();
        // here, data.texture's memory address == 0x0001
        LoadTexture(s, data.texture /*0x0001*/);
    }
}
public void LoadTexture(string filename, Texture2D texture /* this is now 0x0001 */)
{
    texture = content.Load<Texture2D>(filename);
    // now the PARAMETER is set to 0x0002, not data.texture itself.
}

Answer 1

C# passes variables by value – a copy of the reference is passed but the original variable or field remains untouched. Adding out (or ref) makes it pass by reference, which then causes the original variable/field to be updated.