shader simple_material(
    color Diffuse_Color = color(0.6, 0.8, 0.6),
    float Noise_Factor = 0.5,
    output closure color BSDF = diffuse(N))
{
    color material_color = Diffuse_Color * mix(1.0, noise(P * 10.0), Noise_Factor);
    BSDF = material_color * diffuse(N);
}