function normal(shader, t_base, t_second, t_detail)
    shader:begin("null", "avg4")
        :fog(false)
        :zb(false, false)
    shader:sampler("s_base0"):texture(t_base):clamp():f_linear()
    shader:sampler("s_base1"):texture(t_base):clamp():f_linear()
    shader:sampler("s_base2"):texture(t_base):clamp():f_linear()
    shader:sampler("s_base3"):texture(t_base):clamp():f_linear()
end