st->osctail = &st->oscroot;
/* for trackball, two-sided lighting and no face culling */
glLightModeli(GL_LIGHT_MODEL_TWO_SIDE, GL_TRUE);
st->osctail = &st->oscroot;
/* for trackball, two-sided lighting and no face culling */
glLightModeli(GL_LIGHT_MODEL_TWO_SIDE, GL_TRUE);