Scaling a sprite size using a vector2 Monogame C#

Question

so I'm currently working on resolution independence for my game, and I'm testing it out on a sword image. The position changing is working, but whenever I start doing the size I end up with a blank screen.

These are the functions I run to get the new position and size of the sprite.

    private static float CalcRatio(Vector2 size)
    {
        return size.Y / size.X;
    }

    public static Vector2 CalculateNewPos(Vector2 refPos, Vector2 refScreenSize, Vector2 currentScreenSize)
    {
        return new Vector2((refPos.X / refScreenSize.X) * currentScreenSize.X, 
                          (refPos.Y / refScreenSize.Y) * currentScreenSize.Y);
    }

    public static Vector2 CalculateNewSize(Vector2 refSize, Vector2 refScreenSize, Vector2 currenScreenSize)
    {
        float origRatio = CalcRatio(refSize);
        float perW = refSize.X * 100f / refScreenSize.X;
        float newW = perW / 100f * currenScreenSize.X;
        float newH = newW * origRatio;
        return new Vector2(newW, newH);
    }

In the Initialization function in Game1 I run this code:

 graphics.PreferredBackBufferHeight = GraphicsAdapter.DefaultAdapter.CurrentDisplayMode.Height;
 graphics.PreferredBackBufferWidth = GraphicsAdapter.DefaultAdapter.CurrentDisplayMode.Width;
 swordPosition = CalculateNewPos(swordRefPosition, new Vector2(1920, 1080), new Vector2(GraphicsAdapter.DefaultAdapter.CurrentDisplayMode.Width, GraphicsAdapter.DefaultAdapter.CurrentDisplayMode.Height));
 swordSize = CalculateNewSize(swordRefSize, new Vector2(1920, 1080), new Vector2(GraphicsAdapter.DefaultAdapter.CurrentDisplayMode.Width, GraphicsAdapter.DefaultAdapter.CurrentDisplayMode.Height));

In the load function I run this:

swordTexture = content.Load<Texture2D>("SOLDIER_Sword");
swordPosition = new Vector2(300, 0);
swordRefSize = new Vector2(557, 490);
swordSize = new Vector2(557, 490);
swordRefPosition = new Vector2(300, 0);
swordColor = Color.White;
sword = new StaticSprite(swordTexture, swordPosition, swordSize, swordColor);

In update everytime the screen resolution changes (I have buttons set to do that) this:

 graphics.PreferredBackBufferHeight = setHeight;
 graphics.PreferredBackBufferWidth = setWidth;
 graphics.ApplyChanges();
 swordPosition = CalculateNewPos(swordRefPosition, new Vector2(1920, 1080), new Vector2(setWidth, setHeight));
 swordSize = CalculateNewSize(swordRefSize, new Vector2(1920, 1080), new Vector2(setWidth, setHeight));

And in draw:

batch.Draw(swordTexture, swordPosition, null, swordColor, 0f, Vector2.Zero, swordSize, SpriteEffects.None, 0f);

Sorry there is so much code, I'm really stumped and can't pinpoint where it's going wrong, so I just included everything that changes the variables.

Thank you so much for taking the time to look through this.

Answer 1

Note that current display mode is only meaningful if you are fullscreen. It's the VIEWPORT that tells you the width/height of spritebatch's projection matrix.

That said, you should really look into Bjarke's post, because you don't usually want to be rescaling every individual item.