[SFML] undefined reference to vtable for... przy kompilacji klasy pochodnej Drawable i Transformable

class ShapeDisplay
    : public Drawable
     , public Transformable
{
    core::shapes::Shape * sh;
    Color fillColor, borderColor;
    mutable core::FloatRect aabb;
    mutable Transform old;
   
    void updateAABB() const;
   
public:
    ShapeDisplay()
        : sh( NULL )
         , fillColor( Color::Transparent )
         , borderColor( Color::Black )
    { }
    ShapeDisplay( core::shapes::Shape * sh, Color fillColor = Color::Transparent, Color borderColor = Color::Black )
        : sh( sh )
         , fillColor( fillColor )
         , borderColor( borderColor )
    { }
    virtual ~ShapeDisplay() { }
   
    void setShape( core::shapes::Shape * newsh ) { sh = newsh; }
    void setFillColor( Color c ) { assert( sh ); fillColor = c; }
    void setBorderColor( Color c ) { assert( sh ); borderColor = c; }
   
    core::FloatRect getGlobalBounds() const { if( !compareArray( getTransform().getMatrix(), old.getMatrix(), 4 * 4 ) )
        { old = getTransform(); updateAABB(); } return aabb; }
    const core::shapes::Shape * getShape() const { return sh; }
    Color getFillColor() const { return fillColor; }
    Color getBorderColor() const { return borderColor; }
   
    virtual void draw( RenderTarget & target, RenderStates states ) const;
};

//...

void ShapeDisplay::updateAABB() const
{
    //...
}

void ShapeDisplay::draw( RenderTarget & target, RenderStates states ) const
{
    //...
}