From aba474497726de4a0795b7280c5eaaf9f4514eb1 Mon Sep 17 00:00:00 2001
From: tildearrow <me@tildearrow.org>
Date: Sun, 23 Nov 2025 02:27:42 -0500
Subject: [PATCH] DO NOT READ A ZERO POINTER TO GROOVE

---
 src/engine/fileOps/fur.cpp | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/src/engine/fileOps/fur.cpp b/src/engine/fileOps/fur.cpp
index b043c2d27..204c2d502 100644
--- a/src/engine/fileOps/fur.cpp
+++ b/src/engine/fileOps/fur.cpp
@@ -1712,6 +1712,11 @@ bool DivEngine::loadFur(unsigned char* file, size_t len, int variantID) {
     ds.grooves.reserve(groovePtr.size());
     for (size_t i=0; i<groovePtr.size(); i++) {
       DivGroovePattern groove;
+
+      if (groovePtr[i]==0) {
+        // could happen due to a bug in unstable Furnace
+        continue;
+      }
       if (!reader.seek(groovePtr[i],SEEK_SET)) {
         logE("couldn't seek to groove %d!",i);
         lastError=fmt::sprintf("couldn't seek to groove %d!",i);