No, there is no such function. However you can get each point from a sf::Shape by using getPoint(int). Example:
hull->m_vertices.clear();
int count = dRect.rect.getPointCount();
for (int i = count; i>0 ; i--){
sf::Vector2f point = rect.getTransform().transformPoint(rect.getPoint(i));
hull->m_vertices.push_back(Vec2f(point.x,options.screenHeight-point.y));
}
You probably have to fit it to your code, but this was how i did it