From e8de4d088c78ac83f113f2ba2f33168f6f645518 Mon Sep 17 00:00:00 2001
From: Zeno Rogue <zeno@attnam.com>
Date: Sat, 2 Nov 2019 20:28:52 +0100
Subject: [PATCH] fixed a possible crash in hybrid

---
 nonisotropic.cpp | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/nonisotropic.cpp b/nonisotropic.cpp
index 73c0ab87..859ad836 100644
--- a/nonisotropic.cpp
+++ b/nonisotropic.cpp
@@ -1081,7 +1081,7 @@ EX namespace hybrid {
       cell *c1 = hybrid::get_where(c).first;
       wo = isize(cgi.shWall3D);
       int won = wo + c->type;
-      cgi.wallstart.pop_back();
+      if(!cgi.wallstart.empty()) cgi.wallstart.pop_back();
       cgi.reserve_wall3d(won);
       
       if(prod) for(int i=0; i<c1->type; i++) {