wall optimization option (-wallopt): do not draw things behind walls

euclid.cpp

@@ -694,6 +694,7 @@ EX namespace euclid3 {
         cell *c = h->c7;
         if(!do_draw(c, V)) continue;
         drawcell(c, V, 0, false);
+        if(wallopt && isWall3(c) && isize(dq::drawqueue) > 1000) continue;
   
         for(int i=0; i<S7; i++)
           dq::enqueue_by_matrix(h->move(i), V * get_move(h->c7, i));