Don't refresh the 3D view unless really necessary

If you spot a missed refresh, please tell me how to reproduce.

src/slic3r/GUI/GLCanvas3D.cpp

@@ -1339,9 +1339,10 @@ void GLCanvas3D::reset_volumes(bool is_destroying)
 
     _set_current();
 
-        m_selection.clear(is_destroying);
-        m_volumes.clear();
-        m_dirty = true;
+    m_selection.clear(is_destroying);
+    m_volumes.release_geometry();
+    m_volumes.clear();
+    m_dirty = true;
 
     if(!is_destroying)
         _set_warning_texture(WarningTexture::ObjectOutside, false);
@@ -2326,21 +2327,21 @@ static void reserve_new_volume_finalize_old_volume(GLVolume& vol_new, GLVolume&
 	vol_old.finalize_geometry(gl_initialized);
 }
 
-void GLCanvas3D::load_gcode_preview(const GCodeProcessor::Result& gcode_result)
+void GLCanvas3D::load_gcode_preview(const GCodeProcessor::Result& gcode_result, const std::vector<std::string>& str_tool_colors)
 {
-    m_gcode_viewer.load(gcode_result, *this->fff_print(), m_initialized);
+    if (m_dirty_gcode) {
+        m_dirty_gcode = false;
+        m_gcode_viewer.load(gcode_result, *this->fff_print(), m_initialized);
 
-    if (wxGetApp().is_editor()) {
-        m_gcode_viewer.update_shells_color_by_extruder(m_config);
-        _show_warning_texture_if_needed(WarningTexture::ToolpathOutside);
-    }
-}
+        if (wxGetApp().is_editor()) {
+            m_gcode_viewer.update_shells_color_by_extruder(m_config);
+            _show_warning_texture_if_needed(WarningTexture::ToolpathOutside);
+        }
 
-void GLCanvas3D::refresh_gcode_preview(const GCodeProcessor::Result& gcode_result, const std::vector<std::string>& str_tool_colors)
-{
-    m_gcode_viewer.refresh(gcode_result, str_tool_colors);
-    set_as_dirty();
-    request_extra_frame();
+        m_gcode_viewer.refresh(gcode_result, str_tool_colors);
+        set_as_dirty();
+        request_extra_frame();
+    }
 }
 
 #if ENABLE_RENDER_PATH_REFRESH_AFTER_OPTIONS_CHANGE
@@ -2367,23 +2368,27 @@ void GLCanvas3D::load_sla_preview()
 
 void GLCanvas3D::load_preview(const std::vector<std::string>& str_tool_colors, const std::vector<CustomGCode::Item>& color_print_values)
 {
-    const Print *print = this->fff_print();
+    const Print* print = this->fff_print();
     if (print == nullptr)
         return;
 
     _set_current();
 
-    // Release OpenGL data before generating new data.
-    this->reset_volumes();
+    if (m_dirty_preview || m_volumes.empty()) {
+        m_dirty_preview = false;
+        // Release OpenGL data before generating new data.
+        this->reset_volumes();
+        //note: this isn't releasing all the memory in all os, can make it crash on linux for exemple.
 
-    _load_print_toolpaths();
-    _load_wipe_tower_toolpaths(str_tool_colors);
-    for (const PrintObject* object : print->objects())
+        _load_print_toolpaths();
+        _load_wipe_tower_toolpaths(str_tool_colors);
+        for (const PrintObject* object : print->objects())
             _load_print_object_toolpaths(*object, str_tool_colors, color_print_values);
 
-    _update_toolpath_volumes_outside_state();
-    _show_warning_texture_if_needed(WarningTexture::ToolpathOutside);
+        _update_toolpath_volumes_outside_state();
+        _show_warning_texture_if_needed(WarningTexture::ToolpathOutside);
     }
+}
 
 void GLCanvas3D::bind_event_handlers()
 {
@@ -4835,7 +4840,7 @@ bool GLCanvas3D::_init_collapse_toolbar()
 bool GLCanvas3D::_set_current()
 {
     return m_context != nullptr && m_canvas->SetCurrent(*m_context);
-    }
+}
 
 void GLCanvas3D::_resize(unsigned int w, unsigned int h)
 {

src/slic3r/GUI/GLCanvas3D.hpp

@@ -475,6 +475,8 @@ class GLCanvas3D
 
     // Screen is only refreshed from the OnIdle handler if it is dirty.
     bool m_dirty;
+    bool m_dirty_preview = true;
+    bool m_dirty_gcode = true;
     bool m_initialized;
     bool m_apply_zoom_to_volumes_filter;
     mutable std::vector<int> m_hover_volume_idxs;
@@ -557,6 +559,9 @@ class GLCanvas3D
     void post_event(wxEvent &&event);
 
     void set_as_dirty();
+    void set_preview_dirty() { m_dirty_preview = true; }
+    bool is_preview_dirty() { return m_dirty_preview; }
+    void set_gcode_viewer_dirty() { m_dirty_gcode = true; }
     void set_items_show(bool show_objects, bool show_gcode);
 
     unsigned int get_volumes_count() const;
@@ -666,8 +671,7 @@ class GLCanvas3D
 
     void reload_scene(bool refresh_immediately, bool force_full_scene_refresh = false);
 
-    void load_gcode_preview(const GCodeProcessor::Result& gcode_result);
-    void refresh_gcode_preview(const GCodeProcessor::Result& gcode_result, const std::vector<std::string>& str_tool_colors);
+    void load_gcode_preview(const GCodeProcessor::Result& gcode_result, const std::vector<std::string>& str_tool_colors);
 #if ENABLE_RENDER_PATH_REFRESH_AFTER_OPTIONS_CHANGE
     void refresh_gcode_preview_render_paths();
 #endif // ENABLE_RENDER_PATH_REFRESH_AFTER_OPTIONS_CHANGE

src/slic3r/GUI/GUI_Preview.cpp

@@ -416,8 +416,9 @@ void Preview::reload_print(bool keep_volumes)
 #ifdef __linux__
         m_volumes_cleanup_required || 
 #endif /* __linux__ */
-        !keep_volumes)
+        (!keep_volumes && m_canvas->is_preview_dirty()))
     {
+        m_canvas->set_preview_dirty();
         m_canvas->reset_volumes();
         m_loaded = false;
 #ifdef __linux__
@@ -1020,15 +1021,18 @@ void Preview::load_print_as_fff(bool keep_z_range)
         m_canvas->set_selected_extruder(0);
         if (current_force_state == ForceState::ForceGcode || (gcode_preview_data_valid && current_force_state != ForceState::ForceExtrusions)) {
             // Load the real G-code preview.
-            m_canvas->load_gcode_preview(*m_gcode_result);
-            m_canvas->refresh_gcode_preview(*m_gcode_result, colors);
+            if (current_force_state == ForceState::NoForce)
+                m_canvas->set_items_show(false, true);
+            m_canvas->load_gcode_preview(*m_gcode_result, colors);
             m_left_sizer->Show(m_bottom_toolbar_panel);
             m_left_sizer->Layout();
             Refresh();
             zs = m_canvas->get_gcode_layers_zs();
             m_loaded = true;
         } else {
             // Load the initial preview based on slices, not the final G-code.
+            if (current_force_state == ForceState::NoForce)
+                m_canvas->set_items_show(true, false);
             m_canvas->load_preview(colors, color_print_values);
             m_left_sizer->Hide(m_bottom_toolbar_panel);
             m_left_sizer->Layout();
@@ -1039,8 +1043,9 @@ void Preview::load_print_as_fff(bool keep_z_range)
             // all layers filtered out
             hide_layers_slider();
             m_canvas_widget->Refresh();
-        } else
+        } else {
             update_layers_slider(zs, keep_z_range);
+        }
     }
 
 #if ENABLE_PREVIEW_TYPE_CHANGE
@@ -1071,6 +1076,13 @@ void Preview::load_print_as_fff(bool keep_z_range)
 #endif // ENABLE_PREVIEW_TYPE_CHANGE
 }
 
+void Preview::reset_gcode_toolpaths()
+{
+    if (current_force_state == ForceState::NoForce)
+        m_canvas->set_items_show(true, false);
+    m_canvas->reset_gcode_toolpaths();
+}
+
 void Preview::load_print_as_sla()
 {
     if (m_loaded || (m_process->current_printer_technology() != ptSLA))

src/slic3r/GUI/GUI_Preview.hpp

@@ -203,6 +203,7 @@ Preview(wxWindow* parent, Model* model, DynamicPrintConfig* config, BackgroundSl
 
     bool can_display_gcode();
     bool can_display_volume();
+    void reset_gcode_toolpaths();
 
 private:
     ForceState current_force_state = ForceState::NoForce;

src/slic3r/GUI/Plater.cpp

@@ -3576,8 +3576,14 @@ void Plater::priv::set_current_panel(wxTitledPanel* panel)
         // FIXME: it may be better to have a single function making this check and let it be called wherever needed
         bool export_in_progress = this->background_process.is_export_scheduled();
         bool model_fits = view3D->check_volumes_outside_state() != ModelInstancePVS_Partly_Outside;
-        if (!model.objects.empty() && !export_in_progress && model_fits)
-            this->q->reslice();
+
+        if (!model.objects.empty() && !export_in_progress && model_fits) {
+            //check if already slicing
+            bool already_running = this->background_process.state() == BackgroundSlicingProcess::State::STATE_RUNNING ||
+                this->background_process.state() == BackgroundSlicingProcess::State::STATE_STARTED;
+            if(!already_running)
+                this->q->reslice();
+        }
         // keeps current gcode preview, if any
         preview->reload_print(true);
     }
@@ -3722,6 +3728,7 @@ void Plater::priv::on_slicing_update(SlicingStatusEvent &evt)
 
 void Plater::priv::on_slicing_completed(wxCommandEvent & evt)
 {
+    preview->get_canvas3d()->set_gcode_viewer_dirty();
     // auto_switch_preview == 0 means "no force tab change"
     // auto_switch_preview == 1 means "force tab change"
     // auto_switch_preview == 2 means "force tab change only if already on a plater one"
@@ -3753,6 +3760,8 @@ void Plater::priv::on_slicing_began()
 {
 	clear_warnings();
 	notification_manager->close_notification_of_type(NotificationType::SlicingComplete);
+    preview->get_canvas3d()->set_gcode_viewer_dirty();
+    preview->get_canvas3d()->set_preview_dirty();
 }
 void Plater::priv::add_warning(const Slic3r::PrintStateBase::Warning& warning, size_t oid)
 {
@@ -4390,7 +4399,7 @@ void Plater::priv::enable_preview_moves_slider(bool enable)
 
 void Plater::priv::reset_gcode_toolpaths()
 {
-    preview->get_canvas3d()->reset_gcode_toolpaths();
+    preview->reset_gcode_toolpaths();
 }
 
 bool Plater::priv::can_set_instance_to_object() const