= {
{"Ka", MaterialAttribute(glm::vec3())},
{"Kd", MaterialAttribute(glm::vec3())},
{"Ks", MaterialAttribute(glm::vec3())},
{"Ns", MaterialAttribute(0.0f)},
{"d", MaterialAttribute(0.0f)},
{"illum", MaterialAttribute(0)},
{"map_Ka", MaterialAttribute(OptionalSimpleTexture2D())},
{"map_Kd", MaterialAttribute(OptionalSimpleTexture2D())},
{"map_Ks", MaterialAttribute(OptionalSimpleTexture2D())},
{"map_bump", MaterialAttribute(OptionalSimpleTexture2D())},
{"map_d", MaterialAttribute(OptionalSimpleTexture2D())},
{"map_disp", MaterialAttribute(OptionalSimpleTexture2D())}
}