From 5b67fafb75f6cc20c9e3b738756bb032ba0c1b82 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Luk=C3=A1=C5=A1=20Hejl?= <hejl.lukas@gmail.com>
Date: Mon, 19 Jul 2021 10:24:38 +0200
Subject: [PATCH] Fixed a crash in the multi-material gizmo when bucket fill is
 selected.

---
 src/libslic3r/TriangleSelector.cpp | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/src/libslic3r/TriangleSelector.cpp b/src/libslic3r/TriangleSelector.cpp
index b64bef17a..e7be260f6 100644
--- a/src/libslic3r/TriangleSelector.cpp
+++ b/src/libslic3r/TriangleSelector.cpp
@@ -333,6 +333,9 @@ void TriangleSelector::bucket_fill_select_triangles(const Vec3f& hit, int facet_
         if (!visited[current_facet]) {
             m_triangles[current_facet].select_by_seed_fill();
             for(int neighbor_idx : all_level_neighbors[current_facet]) {
+                if(neighbor_idx < 0 || visited[neighbor_idx])
+                    continue;
+
                 if(!m_triangles[neighbor_idx].is_split()) {
                     if(m_triangles[neighbor_idx].get_state() == start_facet_state)
                         facet_queue.push(neighbor_idx);