diff --git a/graph.cpp b/graph.cpp
index 673f665e..093e922b 100644
--- a/graph.cpp
+++ b/graph.cpp
@@ -5075,11 +5075,11 @@ EX shiftmatrix cview(ld base_shift IS(0)) {
 
 EX int point_direction;
 
-EX int through_wall(hyperpoint at) {
+EX int through_wall(cell *c, hyperpoint at) {
   ld dist = hdist0(at);
   int nei = -1;
-  for(int i=0; i<centerover->type; i++) {
-    ld dist1 = hdist0(currentmap->ray_iadj(centerover, i) * at);
+  for(int i=0; i<c->type; i++) {
+    ld dist1 = hdist0(currentmap->ray_iadj(c, i) * at);
     if(dist1 < dist) nei = i, dist = dist1;
     }
   return nei;
@@ -5094,7 +5094,7 @@ EX void precise_mouseover() {
     cell *c = centerover;
     for(int i=0; i<100; i++) {
       apply_parallel_transport(T, ori, ztangent(step));
-      int pd = through_wall(T * C0);
+      int pd = through_wall(c, T * C0);
       if(pd != -1) {
         color_t col;
         cell *c1 = c->cmove(pd);
diff --git a/intra.cpp b/intra.cpp
index c9bc421d..f25e82a5 100644
--- a/intra.cpp
+++ b/intra.cpp
@@ -546,7 +546,7 @@ EX void shift_view_portal(hyperpoint H) {
 
 EX const connection_data* through_portal() {
   transmatrix iView = view_inverse(View);
-  int nei = through_wall(iView * C0);
+  int nei = through_wall(centerover, iView * C0);
   if(nei == -1) return nullptr;
   auto cw1 = cellwalker(centerover, nei);
   return at_or_null(connections, cw1);