Two Sided Materials
GLfloat
outside = {0.2, 1.0, 1.0, 1.0};
GLfloat
inside = {1.0, 0.5, 0.5, 1.0};
…
glMaterialfv(GL_FRONT,
GL_DIFFUSE, outside);
glMaterialfv(GL_BACK,
GL_DIFFUSE, inside);
…
glLightModelf(GL_LIGHT_MODEL_TWO_SIDE,
GL_TRUE);