From fe07bde3852f699176570cefc73dfd12b6815020 Mon Sep 17 00:00:00 2001
From: Enrico Turri <enricoturri@seznam.cz>
Date: Fri, 6 Sep 2019 13:49:15 +0200
Subject: [PATCH] Do not render intermediate states while reload from disk
 action is taking place

---
 src/slic3r/GUI/GLCanvas3D.cpp | 3 ++-
 src/slic3r/GUI/GLCanvas3D.hpp | 4 ++++
 src/slic3r/GUI/Plater.cpp     | 6 ++++++
 3 files changed, 12 insertions(+), 1 deletion(-)

diff --git a/src/slic3r/GUI/GLCanvas3D.cpp b/src/slic3r/GUI/GLCanvas3D.cpp
index 0494af3d5..a6abc83fd 100644
--- a/src/slic3r/GUI/GLCanvas3D.cpp
+++ b/src/slic3r/GUI/GLCanvas3D.cpp
@@ -1127,6 +1127,7 @@ GLCanvas3D::GLCanvas3D(wxGLCanvas* canvas, Bed3D& bed, Camera& camera, GLToolbar
     , m_retina_helper(nullptr)
 #endif
     , m_in_render(false)
+    , m_render_enabled(true)
     , m_bed(bed)
     , m_camera(camera)
     , m_view_toolbar(view_toolbar)
@@ -1513,7 +1514,7 @@ void GLCanvas3D::update_volumes_colors_by_extruder()
 
 void GLCanvas3D::render()
 {
-    if (m_in_render)
+    if (!m_render_enabled || m_in_render)
     {
         // if called recursively, return
         m_dirty = true;
diff --git a/src/slic3r/GUI/GLCanvas3D.hpp b/src/slic3r/GUI/GLCanvas3D.hpp
index 879584528..d805cd60f 100644
--- a/src/slic3r/GUI/GLCanvas3D.hpp
+++ b/src/slic3r/GUI/GLCanvas3D.hpp
@@ -403,6 +403,7 @@ private:
     std::unique_ptr<RetinaHelper> m_retina_helper;
 #endif
     bool m_in_render;
+    bool m_render_enabled;
     LegendTexture m_legend_texture;
     WarningTexture m_warning_texture;
     wxTimer m_timer;
@@ -533,6 +534,9 @@ public:
     void enable_dynamic_background(bool enable);
     void allow_multisample(bool allow);
 
+    void enable_render(bool enable) { m_render_enabled = enable; }
+    bool is_render_enabled() const { return m_render_enabled; }
+
     void zoom_to_bed();
     void zoom_to_volumes();
     void zoom_to_selection();
diff --git a/src/slic3r/GUI/Plater.cpp b/src/slic3r/GUI/Plater.cpp
index 4442c65e4..6e2d3b1b5 100644
--- a/src/slic3r/GUI/Plater.cpp
+++ b/src/slic3r/GUI/Plater.cpp
@@ -3087,6 +3087,9 @@ void Plater::priv::reload_from_disk()
     auto *object_orig = model.objects[obj_orig_idx];
     std::vector<fs::path> input_paths(1, object_orig->input_file);
 
+    // disable render to avoid to show intermediate states
+    view3D->get_canvas3d()->enable_render(false);
+
     const auto new_idxs = load_files(input_paths, true, false);
 
     for (const auto idx : new_idxs) {
@@ -3108,6 +3111,9 @@ void Plater::priv::reload_from_disk()
 
     remove(obj_orig_idx);
 
+    // re-enable render 
+    view3D->get_canvas3d()->enable_render(true);
+
     // the previous call to remove() clears the selection
     // select newly added objects
     selection.clear();