private static SliderStyle genDefaultSliderStyle(){
SliderStyle style = new SliderStyle();
style.knob = new TextureRegionDrawable(new TextureRegion(getTexture("slider_knob")));
NinePatch p = new NinePatch(getTexture("slider_before"), 4, 4, 0, 0);
style.knobBefore = new NinePatchDrawable(p);
p = new NinePatch(getTexture("slider_after"), 4, 4, 0, 0);
style.background = new NinePatchDrawable(p);
return style;
}