public void setSemiTransparency(double alpha) {
        if (parent == null) // the Sprite must have a specific parent component to load its filtered image properly. See render(Graphics2D g).
            semiTransparency = 1.0;

        if (alpha > 1.0)
            alpha = 1.0;
        if (alpha < 0.0)
            alpha = 0.0;

        colorTransformChanged = true;
        semiTransparency = alpha;
    }