Added method const GLVolume* Selection::get_first_volume() const to simplify client code

(cherry picked from commit prusa3d/PrusaSlicer@0e3490620e)

src/slic3r/GUI/GUI_ObjectList.cpp

@@ -1950,7 +1950,7 @@ void ObjectList::load_modifier(const wxArrayString& input_files, ModelObject& mo
     const BoundingBoxf3 instance_bb = model_object.instance_bounding_box(instance_idx);
 
     // First (any) GLVolume of the selected instance. They all share the same instance matrix.
-    const GLVolume* v = selection.get_volume(*selection.get_volume_idxs().begin());
+    const GLVolume* v = selection.get_first_volume();
     const Geometry::Transformation inst_transform = v->get_instance_transformation();
     const Transform3d inv_inst_transform = inst_transform.get_matrix(true).inverse();
     const Vec3d instance_offset = v->get_instance_offset();
@@ -2086,7 +2086,7 @@ void ObjectList::load_generic_subobject(const std::string& type_name, const Mode
     ModelVolume *new_volume = model_object.add_volume(std::move(mesh), type);
 
     // First (any) GLVolume of the selected instance. They all share the same instance matrix.
-    const GLVolume* v = selection.get_volume(*selection.get_volume_idxs().begin());
+    const GLVolume* v = selection.get_first_volume();
     // Transform the new modifier to be aligned with the print bed.
 	const BoundingBoxf3 mesh_bb = new_volume->mesh().bounding_box();
     new_volume->set_transformation(Geometry::Transformation::volume_to_bed_transformation(v->get_instance_transformation(), mesh_bb));
@@ -4350,7 +4350,7 @@ void ObjectList::update_selections()
             sels.Add(m_objects_model->GetItemById(selection.get_object_idx()));
         }
         else if (selection.is_single_volume() || selection.is_any_modifier()) {
-            const auto gl_vol = selection.get_volume(*selection.get_volume_idxs().begin());
+            const auto gl_vol = selection.get_first_volume();
             if (m_objects_model->GetVolumeIdByItem(m_objects_model->GetParent(item)) == gl_vol->volume_idx())
                 return;
         }
@@ -4426,8 +4426,7 @@ void ObjectList::update_selections()
     {
         if (m_selection_mode & smSettings)
         {
-            const auto idx = *selection.get_volume_idxs().begin();
+            const auto gl_vol = selection.get_first_volume();
-            const auto gl_vol = selection.get_volume(idx);
             if (gl_vol->volume_idx() >= 0) {
                 // Only add GLVolumes with non-negative volume_ids. GLVolumes with negative volume ids
                 // are not associated with ModelVolumes, but they are temporarily generated by the backend

src/slic3r/GUI/Gizmos/GLGizmoAdvancedCut.cpp

@@ -621,7 +621,7 @@ void GLGizmoAdvancedCut::perform_cut(const Selection& selection)
     wxCHECK_RET(instance_idx >= 0 && object_idx >= 0, "GLGizmoAdvancedCut: Invalid object selection");
 
     // m_cut_z is the distance from the bed. Subtract possible SLA elevation.
-    const GLVolume* first_glvolume = selection.get_volume(*selection.get_volume_idxs().begin());
+    const GLVolume* first_glvolume = selection.get_first_volume();
 
     // perform cut
     {

src/slic3r/GUI/Gizmos/GLGizmoPainterBase.cpp

@@ -341,7 +341,7 @@ BoundingBoxf3 GLGizmoPainterBase::bounding_box() const
 void GLGizmoPainterBase::update_contours(const TriangleMesh& vol_mesh, float cursor_z, float max_z, float min_z) const
 {
     const Selection& selection = m_parent.get_selection();
-    const GLVolume* first_glvolume = selection.get_volume(*selection.get_volume_idxs().begin());
+    const GLVolume* first_glvolume = selection.get_first_volume();
     const BoundingBoxf3& box = first_glvolume->transformed_convex_hull_bounding_box();
 
     const ModelObject* model_object = wxGetApp().model().objects[selection.get_object_idx()];

src/slic3r/GUI/Gizmos/GLGizmoRotate.cpp

@@ -432,7 +432,7 @@ Transform3d GLGizmoRotate::local_transform(const Selection& selection) const
     }
 
     if (selection.is_single_volume() || selection.is_single_modifier() || selection.requires_local_axes())
-        ret = selection.get_volume(*selection.get_volume_idxs().begin())->get_instance_transformation().get_matrix(true, false, true, true) * ret;
+        ret = selection.get_first_volume()->get_instance_transformation().get_matrix(true, false, true, true) * ret;
 
     return Geometry::assemble_transform(m_center) * ret;
 }
@@ -466,7 +466,7 @@ Vec3d GLGizmoRotate::mouse_position_in_local_plane(const Linef3& mouse_ray, cons
     }
 
     if (selection.is_single_volume() || selection.is_single_modifier() || selection.requires_local_axes())
-        m = m * selection.get_volume(*selection.get_volume_idxs().begin())->get_instance_transformation().get_matrix(true, false, true, true).inverse();
+        m = m * selection.get_first_volume()->get_instance_transformation().get_matrix(true, false, true, true).inverse();
 
     m.translate(-m_center);
 

src/slic3r/GUI/Gizmos/GLGizmoScale.cpp

@@ -49,9 +49,9 @@ std::string GLGizmoScale3D::get_tooltip() const
 
     Vec3f scale = 100.0f * Vec3f::Ones();
     if (single_instance)
-        scale = 100.0f * selection.get_volume(*selection.get_volume_idxs().begin())->get_instance_scaling_factor().cast<float>();
+        scale = 100.0f * selection.get_first_volume()->get_instance_scaling_factor().cast<float>();
     else if (single_volume)
-        scale = 100.0f * selection.get_volume(*selection.get_volume_idxs().begin())->get_volume_scaling_factor().cast<float>();
+        scale = 100.0f * selection.get_first_volume()->get_volume_scaling_factor().cast<float>();
 
     if (m_hover_id == 0 || m_hover_id == 1 || m_grabbers[0].dragging || m_grabbers[1].dragging)
         return "X: " + format(scale.x(), 4) + "%";
@@ -105,7 +105,7 @@ void GLGizmoScale3D::data_changed()
     if (enable_scale_xyz) {
         // all volumes in the selection belongs to the same instance, any of
         // them contains the needed data, so we take the first
-        const GLVolume *volume = selection.get_volume(*selection.get_volume_idxs().begin());
+        const GLVolume *volume = selection.get_first_volume();
         if (selection.is_single_full_instance()) {
             set_scale(volume->get_instance_scaling_factor());
         } else if (selection.is_single_volume() ||
@@ -211,7 +211,7 @@ void GLGizmoScale3D::on_render()
         }
 
         // gets transform from first selected volume
-        const GLVolume* v = selection.get_volume(*idxs.begin());
+        const GLVolume* v = selection.get_first_volume();
         m_transform = v->get_instance_transformation().get_matrix();
         // gets angles from first selected volume
         angles = v->get_instance_rotation();
@@ -220,7 +220,7 @@ void GLGizmoScale3D::on_render()
         m_offsets_transform = offsets_transform;
     }
     else if (single_volume) {
-        const GLVolume* v = selection.get_volume(*selection.get_volume_idxs().begin());
+        const GLVolume* v = selection.get_first_volume();
         m_box = v->bounding_box();
         m_transform = v->world_matrix();
         angles = Geometry::extract_euler_angles(m_transform);

src/slic3r/GUI/Gizmos/GLGizmoText.cpp

@@ -652,7 +652,7 @@ void GLGizmoText::on_render_input_window(float x, float y, float bottom_limit)
 
     const Selection &selection = m_parent.get_selection();
     if (selection.is_single_full_instance() || selection.is_single_full_object()) {
-        const GLVolume * gl_volume = selection.get_volume(*selection.get_volume_idxs().begin());
+        const GLVolume * gl_volume = selection.get_first_volume();
         int object_idx = gl_volume->object_idx();
         if (object_idx != m_object_idx || (object_idx == m_object_idx && m_volume_idx != -1)) {
             m_object_idx = object_idx;
@@ -917,7 +917,7 @@ ModelVolume *GLGizmoText::get_selected_single_volume(int &out_object_idx, int &o
 {
     if (m_parent.get_selection().is_single_volume() || m_parent.get_selection().is_single_modifier()) {
         const Selection &selection = m_parent.get_selection();
-        const GLVolume * gl_volume = selection.get_volume(*selection.get_volume_idxs().begin());
+        const GLVolume * gl_volume = selection.get_first_volume();
         out_object_idx             = gl_volume->object_idx();
         ModelObject *model_object  = selection.get_model()->objects[out_object_idx];
         out_volume_idx             = gl_volume->volume_idx();

src/slic3r/GUI/Gizmos/GLGizmosCommon.cpp

@@ -119,7 +119,7 @@ void SelectionInfo::on_update()
     const Selection& selection = get_pool()->get_canvas()->get_selection();
     if (selection.is_single_full_instance()) {
         m_model_object = selection.get_model()->objects[selection.get_object_idx()];
-        m_z_shift = selection.get_volume(*selection.get_volume_idxs().begin())->get_sla_shift_z();
+        m_z_shift = selection.get_first_volume()->get_sla_shift_z();
     }
     else
         m_model_object = nullptr;

src/slic3r/GUI/Gizmos/GizmoObjectManipulation.cpp

@@ -86,7 +86,7 @@ void GizmoObjectManipulation::update_settings_value(const Selection& selection)
     ObjectList* obj_list = wxGetApp().obj_list();
     if (selection.is_single_full_instance()) {
         // all volumes in the selection belongs to the same instance, any of them contains the needed instance data, so we take the first one
-        const GLVolume* volume = selection.get_volume(*selection.get_volume_idxs().begin());
+        const GLVolume* volume = selection.get_first_volume();
         m_new_position = volume->get_instance_offset();
 
         if (m_world_coordinates) {
@@ -118,7 +118,7 @@ void GizmoObjectManipulation::update_settings_value(const Selection& selection)
     }
     else if (selection.is_single_modifier() || selection.is_single_volume()) {
         // the selection contains a single volume
-        const GLVolume* volume = selection.get_volume(*selection.get_volume_idxs().begin());
+        const GLVolume* volume = selection.get_first_volume();
         m_new_position = volume->get_volume_offset();
         m_new_rotation = volume->get_volume_rotation() * (180. / M_PI);
         m_new_scale    = volume->get_volume_scaling_factor() * 100.;
@@ -217,7 +217,7 @@ void GizmoObjectManipulation::update_reset_buttons_visibility()
     const Selection& selection = m_glcanvas.get_selection();
 
     if (selection.is_single_full_instance() || selection.is_single_modifier() || selection.is_single_volume()) {
-        const GLVolume* volume = selection.get_volume(*selection.get_volume_idxs().begin());
+        const GLVolume* volume = selection.get_first_volume();
         Vec3d rotation;
         Vec3d scale;
         double min_z = 0.;
@@ -331,14 +331,14 @@ void GizmoObjectManipulation::change_size_value(int axis, double value)
 
     Vec3d ref_size = m_cache.size;
     if (selection.is_single_volume() || selection.is_single_modifier()) {
-        Vec3d instance_scale = wxGetApp().model().objects[selection.get_volume(*selection.get_volume_idxs().begin())->object_idx()]->instances[0]->get_transformation().get_scaling_factor();
+        Vec3d instance_scale = wxGetApp().model().objects[selection.get_first_volume()->object_idx()]->instances[0]->get_transformation().get_scaling_factor();
-        ref_size = selection.get_volume(*selection.get_volume_idxs().begin())->bounding_box().size();
+        ref_size = selection.get_first_volume()->bounding_box().size();
         ref_size = Vec3d(instance_scale[0] * ref_size[0], instance_scale[1] * ref_size[1], instance_scale[2] * ref_size[2]);
     }
     else if (selection.is_single_full_instance())
 		ref_size = m_world_coordinates ? 
             selection.get_unscaled_instance_bounding_box().size() :
-            wxGetApp().model().objects[selection.get_volume(*selection.get_volume_idxs().begin())->object_idx()]->raw_mesh_bounding_box().size();
+            wxGetApp().model().objects[selection.get_first_volume()->object_idx()]->raw_mesh_bounding_box().size();
 
     this->do_scale(axis, 100. * Vec3d(size(0) / ref_size(0), size(1) / ref_size(1), size(2) / ref_size(2)));
 
@@ -391,7 +391,7 @@ void GizmoObjectManipulation::reset_position_value()
     Selection& selection = m_glcanvas.get_selection();
 
     if (selection.is_single_volume() || selection.is_single_modifier()) {
-        GLVolume* volume = const_cast<GLVolume*>(selection.get_volume(*selection.get_volume_idxs().begin()));
+        GLVolume* volume = const_cast<GLVolume*>(selection.get_first_volume());
         volume->set_volume_offset(Vec3d::Zero());
     }
     else if (selection.is_single_full_instance()) {
@@ -414,7 +414,7 @@ void GizmoObjectManipulation::reset_rotation_value()
     Selection& selection = m_glcanvas.get_selection();
 
     if (selection.is_single_volume() || selection.is_single_modifier()) {
-        GLVolume* volume = const_cast<GLVolume*>(selection.get_volume(*selection.get_volume_idxs().begin()));
+        GLVolume* volume = const_cast<GLVolume*>(selection.get_first_volume());
         volume->set_volume_rotation(Vec3d::Zero());
     }
     else if (selection.is_single_full_instance()) {
@@ -450,7 +450,7 @@ void GizmoObjectManipulation::set_uniform_scaling(const bool new_value)
 	if (selection.is_single_full_instance() && m_world_coordinates && !new_value) {
         // Verify whether the instance rotation is multiples of 90 degrees, so that the scaling in world coordinates is possible.
         // all volumes in the selection belongs to the same instance, any of them contains the needed instance data, so we take the first one
-        const GLVolume* volume = selection.get_volume(*selection.get_volume_idxs().begin());
+        const GLVolume* volume = selection.get_first_volume();
         // Is the angle close to a multiple of 90 degrees?
 
 		if (! Geometry::is_rotation_ninety_degrees(volume->get_instance_rotation())) {

src/slic3r/GUI/Plater.cpp

@@ -4033,7 +4033,7 @@ int Plater::priv::get_selected_volume_idx() const
     int idx = selection.get_object_idx();
     if ((0 > idx) || (idx > 1000))
         return-1;
-    const GLVolume* v = selection.get_volume(*selection.get_volume_idxs().begin());
+    const GLVolume* v = selection.get_first_volume();
     if (model.objects[idx]->volumes.size() > 1)
         return v->volume_idx();
     return -1;
@@ -4844,7 +4844,7 @@ void Plater::priv::replace_with_stl()
     if (selection.is_wipe_tower() || get_selection().get_volume_idxs().size() != 1)
         return;
 
-    const GLVolume* v = selection.get_volume(*selection.get_volume_idxs().begin());
+    const GLVolume* v = selection.get_first_volume();
     int object_idx = v->object_idx();
     int volume_idx = v->volume_idx();
 
@@ -7154,7 +7154,7 @@ bool Plater::priv::can_edit_text() const
         return true;
 
     if (selection.is_single_volume()) {
-        const GLVolume *gl_volume      = selection.get_volume(*selection.get_volume_idxs().begin());
+        const GLVolume *gl_volume      = selection.get_first_volume();
         int             out_object_idx = gl_volume->object_idx();
         ModelObject *   model_object   = selection.get_model()->objects[out_object_idx];
         int             out_volume_idx = gl_volume->volume_idx();
@@ -10334,7 +10334,7 @@ void Plater::export_stl(bool extended, bool selection_only)
             if (selection.get_mode() == Selection::Instance)
                 mesh = mesh_to_export(*model_object, (model_object->instances.size() > 1) ? -1 : selection.get_instance_idx());
             else {
-                const GLVolume* volume = selection.get_volume(*selection.get_volume_idxs().begin());
+                const GLVolume* volume = selection.get_first_volume();
                 mesh = model_object->volumes[volume->volume_idx()]->mesh();
                 mesh.transform(volume->get_volume_transformation().get_matrix(), true);
             }