From 7c834de6abe7ce00ac113b63301b7a8845559a6d Mon Sep 17 00:00:00 2001
From: tamasmeszaros <meszaros.q@gmail.com>
Date: Tue, 10 Jan 2023 09:42:53 +0100
Subject: [PATCH] Fix crash when selecting an object

issue no. 11
---
 src/slic3r/GUI/GLCanvas3D.cpp | 13 +++++++++++++
 src/slic3r/GUI/GLCanvas3D.hpp |  2 ++
 src/slic3r/GUI/Selection.cpp  |  4 ++--
 3 files changed, 17 insertions(+), 2 deletions(-)

diff --git a/src/slic3r/GUI/GLCanvas3D.cpp b/src/slic3r/GUI/GLCanvas3D.cpp
index 419e5fbc96..fa94e6abf8 100644
--- a/src/slic3r/GUI/GLCanvas3D.cpp
+++ b/src/slic3r/GUI/GLCanvas3D.cpp
@@ -7055,5 +7055,18 @@ void GLCanvas3D::GizmoHighlighter::blink()
         invalidate();
 }
 
+const ModelVolume *get_model_volume(const GLVolume &v, const Model &model)
+{
+    const ModelVolume * ret = nullptr;
+
+    if (model.objects.size() < v.object_idx()) {
+        const ModelObject *obj = model.objects[v.object_idx()];
+        if (obj->volumes.size() < v.volume_idx())
+            ret = obj->volumes[v.volume_idx()];
+    }
+
+    return ret;
+}
+
 } // namespace GUI
 } // namespace Slic3r
diff --git a/src/slic3r/GUI/GLCanvas3D.hpp b/src/slic3r/GUI/GLCanvas3D.hpp
index 7b5a1084c1..198ecb1d81 100644
--- a/src/slic3r/GUI/GLCanvas3D.hpp
+++ b/src/slic3r/GUI/GLCanvas3D.hpp
@@ -1046,6 +1046,8 @@ private:
     float get_overlay_window_width() { return LayersEditing::get_overlay_window_width(); }
 };
 
+const ModelVolume * get_model_volume(const GLVolume &v, const Model &model);
+
 } // namespace GUI
 } // namespace Slic3r
 
diff --git a/src/slic3r/GUI/Selection.cpp b/src/slic3r/GUI/Selection.cpp
index a70698b438..42331f3a70 100644
--- a/src/slic3r/GUI/Selection.cpp
+++ b/src/slic3r/GUI/Selection.cpp
@@ -1974,8 +1974,8 @@ std::vector<unsigned int> Selection::get_volume_idxs_from_instance(unsigned int
 
     for (unsigned int i = 0; i < (unsigned int)m_volumes->size(); ++i) {
         const GLVolume* v = (*m_volumes)[i];
-        if (pt == ptSLA && v->is_modifier &&
-            m_model->objects[object_idx]->volumes[i]->is_modifier())
+        const ModelVolume *mv = get_model_volume(*v, *m_model);
+        if (pt == ptSLA && v->is_modifier && mv && mv->is_modifier())
             continue;
         if (v->object_idx() == (int)object_idx && v->instance_idx() == (int)instance_idx)
             idxs.push_back(i);