glMaterialfv(GL_FRONT_AND_BACK, GL_DIFFUSE, material_diffuse);
glMaterialfv(GL_FRONT_AND_BACK, GL_SPECULAR, material_specular);
glMaterialf(GL_FRONT_AND_BACK, GL_SHININESS, shininess);
glMaterialfv(GL_FRONT_AND_BACK, GL_DIFFUSE, material_diffuse);
glMaterialfv(GL_FRONT_AND_BACK, GL_SPECULAR, material_specular);
glMaterialf(GL_FRONT_AND_BACK, GL_SHININESS, shininess);