I also use Farseer Physics and Artemis ECS. Here is RenderingSystem Process method:

    public override void Process(Entity entity, TransformComponent transformComponent, RenderingComponent renderingComponent)
        Vector2 dimension = transformComponent.Dimension * camera.ScalingFactor;

        Vector2 rotationOrigin = new Vector2(dimension.X,dimension.Y)/2;

        Vector2 renderingPosition = new Vector2(1, -1) * transformComponent.RenderingPosition * camera.ScalingFactor + camera.BitmapPosition;

        Rectangle rectangle = new Rectangle((int)(renderingPosition.X), (int)(renderingPosition.Y), (int)dimension.X, (int)dimension.Y);

        spriteBatch.Draw(renderingComponent.Texture, rectangle, 
            null, Color.Wheat, -transformComponent.Rotation,rotationOrigin, SpriteEffects.None, 0f);

That's what i get: enter image description here

And that's what I get if

Vector2 rotationOrigin = new Vector2.Zero;

enter image description here

What's the reason for such a weird behavoir of rotationOrigin parameter and how to correctly rotate the sprite around its center?


Turns out the origin parameter represents an offset in the sprite's original terxture, not the scaled one being showed on screen. So here is the correct version:

Vector2 dimension = transformComponent.Dimension * camera.ScalingFactor;

        Vector2 rotationOrigin = new Vector2(dimension.X/2,dimension.Y / 2);

        Vector2 renderingPosition = new Vector2(1, -1) * transformComponent.Position * camera.ScalingFactor + camera.BitmapPosition;

             new Vector2(
                 renderingComponent.Texture.Width / 2,
                 renderingComponent.Texture.Height / 2),
             new Vector2(dimension.X / renderingComponent.Texture.Width, dimension.Y / renderingComponent.Texture.Height),

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