std::vector<float> bkgd_top_color, bkgd_bottom_color;
if(!reader.get("top_color", bkgd_top_color) ||
!reader.get("bottom_color", bkgd_bottom_color))
std::vector<float> bkgd_top_color, bkgd_bottom_color;
if(!reader.get("top_color", bkgd_top_color) ||
!reader.get("bottom_color", bkgd_bottom_color))