+ /* Enable visibility-from-behind. */
+
+ if ((mp->fl & M_TWO_SIDED) && !(mq->fl & M_TWO_SIDED))
+ {
+ glDisable(GL_CULL_FACE);
+ glLightModeli(GL_LIGHT_MODEL_TWO_SIDE, 1);
+ }
+
+ /* Disable visibility-from-behind. */
+
+ if ((mq->fl & M_TWO_SIDED) && !(mp->fl & M_TWO_SIDED))
+ {
+ glEnable(GL_CULL_FACE);
+ glLightModeli(GL_LIGHT_MODEL_TWO_SIDE, 0);
+ }
+