From 16ff0ba30a9a3e7ad81853b7983509f4d3e7dc65 Mon Sep 17 00:00:00 2001
From: Jane Tournois <jane.tournois@geometryfactory.com>
Date: Tue, 17 Jun 2025 17:22:33 +0200
Subject: [PATCH] c3t3 is "valid" only if generated by Mesh_3, not if loaded
 from a .mesh file

this disables the demo to save a mesh that was just loaded, or loaded+remeshed
for example

this commit fixes that bevaviour
---
 Lab/demo/Lab/Plugins/Mesh_3/C3t3_io_plugin.cpp | 15 +++++++--------
 1 file changed, 7 insertions(+), 8 deletions(-)

diff --git a/Lab/demo/Lab/Plugins/Mesh_3/C3t3_io_plugin.cpp b/Lab/demo/Lab/Plugins/Mesh_3/C3t3_io_plugin.cpp
index af885246ea4..69095bf9de4 100644
--- a/Lab/demo/Lab/Plugins/Mesh_3/C3t3_io_plugin.cpp
+++ b/Lab/demo/Lab/Plugins/Mesh_3/C3t3_io_plugin.cpp
@@ -196,14 +196,8 @@ CGAL_Lab_c3t3_binary_io_plugin::
 save(QFileInfo fileinfo, QList<Scene_item *> &items)
 {
   Scene_item* item = items.front();
-  if(!qobject_cast<Scene_c3t3_item*>(item)->is_valid())
-  {
-    QMessageBox::warning(CGAL::Three::Three::mainWindow(), "", "The c3t3_item is not valid. You cannot save it.");
-    return false;
-  }
   const Scene_c3t3_item* c3t3_item = qobject_cast<const Scene_c3t3_item*>(item);
-  if ( NULL == c3t3_item )
-  {
+  if(nullptr == c3t3_item) {
     return false;
   }
 
@@ -211,9 +205,14 @@ save(QFileInfo fileinfo, QList<Scene_item *> &items)
 
   if(path.endsWith(".cgal"))
   {
+    if(!c3t3_item->is_valid())
+    {
+      QMessageBox::warning(CGAL::Three::Three::mainWindow(), "",
+                           "The c3t3_item is not valid. You cannot save it in binary cgal format.");
+      return false;
+    }
     std::ofstream out(fileinfo.filePath().toUtf8(),
                       std::ios_base::out|std::ios_base::binary);
-
     bool ok = out && c3t3_item->save_binary(out);
     if(!ok)
       return false;