- /* FIXME */
- v3_copy( (v3f){0.0f,1.0f,0.0f}, inf_avg.n );
+ v3f axis_front, axis_back, axis;
+ v3_cross( inf_front->dir, inf_front->n, axis_front );
+ v3_cross( inf_back->dir, inf_back->n, axis_back );
+ v3_add( axis_front, axis_back, axis );
+ v3_normalize( axis );
+
+ v3_cross( axis, inf_avg.dir, inf_avg.n );