Take the print config by reference while simplifying extrusions

simplify_path, simplify_multi_path and simplify_loop each copied the whole
PrintConfig, 10520 bytes with around 200 heap owning members, once per extrusion
entity, from inside the parallel_for over all layers. LayerRegion.cpp already
binds a reference a few hundred lines above. Three more sites in Layer.cpp do the
same thing.

The tree support changes in the same area: draw_circles() dropped layers from an
owning vector without deleting them, so every re-slice leaked the layers above
the topmost overhang. std::stable_partition rather than std::remove_if, because
remove_if leaves moved-from duplicates of kept pointers in the tail and deleting
those would be a double free. The collision and avoidance accessors returned
ExPolygons by value out of a cache that hands them out by reference, several
times per node per layer. The preview cache is released when the support step
finishes instead of at the start of the next slice; nothing reads it in between.

set_shared_object() now releases the layers the object still owns before it
starts aliasing another object's. Both clear functions are no-ops once the alias
is set, so this cannot free the sharee's layers.

PrintObjectSlice.cpp: eps was a function local static inside a parallel_for, so
slice_closing_radius was latched once per process. This one changes output for
projects that override it per object, or on a re-slice after editing it. The old
behaviour was undefined: whichever object won the race set it for the session.

src/libslic3r/Layer.cpp

@@ -360,7 +360,7 @@ void Layer::simplify_support_entity_collection(ExtrusionEntityCollection* entity
 //BBS: method to simplify support path
 void Layer::simplify_support_path(ExtrusionPath * path)
 {
-    const auto print_config = this->object()->print()->config();
+    const PrintConfig &print_config = this->object()->print()->config();
     const bool spiral_mode = print_config.spiral_mode;
     const bool enable_arc_fitting = print_config.enable_arc_fitting;
     const auto scaled_resolution = scaled<double>(print_config.resolution.value);
@@ -375,7 +375,7 @@ void Layer::simplify_support_path(ExtrusionPath * path)
 //BBS: method to simplify support path
 void Layer::simplify_support_multi_path(ExtrusionMultiPath* multipath)
 {
-    const auto print_config = this->object()->print()->config();
+    const PrintConfig &print_config = this->object()->print()->config();
     const bool spiral_mode = print_config.spiral_mode;
     const bool enable_arc_fitting = print_config.enable_arc_fitting;
     const auto scaled_resolution = scaled<double>(print_config.resolution.value);
@@ -392,7 +392,7 @@ void Layer::simplify_support_multi_path(ExtrusionMultiPath* multipath)
 //BBS: method to simplify support path
 void Layer::simplify_support_loop(ExtrusionLoop* loop)
 {
-    const auto print_config = this->object()->print()->config();
+    const PrintConfig &print_config = this->object()->print()->config();
     const bool spiral_mode = print_config.spiral_mode;
     const bool enable_arc_fitting = print_config.enable_arc_fitting;
     const auto scaled_resolution = scaled<double>(print_config.resolution.value);

src/libslic3r/LayerRegion.cpp

@@ -1074,7 +1074,7 @@ void LayerRegion::simplify_entity_collection(ExtrusionEntityCollection* entity_c
 
 void LayerRegion::simplify_path(ExtrusionPath* path)
 {
-    const auto print_config = this->layer()->object()->print()->config();
+    const PrintConfig &print_config = this->layer()->object()->print()->config();
     const bool spiral_mode = print_config.spiral_mode;
     const bool enable_arc_fitting = print_config.enable_arc_fitting;
     const auto scaled_resolution = scaled<double>(print_config.resolution.value);
@@ -1092,7 +1092,7 @@ void LayerRegion::simplify_path(ExtrusionPath* path)
 
 void LayerRegion::simplify_multi_path(ExtrusionMultiPath* multipath)
 {
-    const auto print_config = this->layer()->object()->print()->config();
+    const PrintConfig &print_config = this->layer()->object()->print()->config();
     const bool spiral_mode = print_config.spiral_mode;
     const bool enable_arc_fitting = print_config.enable_arc_fitting;
     const auto scaled_resolution = scaled<double>(print_config.resolution.value);
@@ -1112,7 +1112,7 @@ void LayerRegion::simplify_multi_path(ExtrusionMultiPath* multipath)
 
 void LayerRegion::simplify_loop(ExtrusionLoop* loop)
 {
-    const auto print_config = this->layer()->object()->print()->config();
+    const PrintConfig &print_config = this->layer()->object()->print()->config();
     const bool spiral_mode = print_config.spiral_mode;
     const bool enable_arc_fitting = print_config.enable_arc_fitting;
     const auto scaled_resolution = scaled<double>(print_config.resolution.value);

src/libslic3r/Print.cpp

@@ -2604,6 +2604,11 @@ void Print::auto_assign_extruders(ModelObject* model_object) const
 
 void  PrintObject::set_shared_object(PrintObject *object)
 {
+    // Orca: from now on m_layers / m_support_layers only alias the shared object's layers, so release the
+    // ones this object still owns (it may have sliced itself before it became shareable again).
+    // Both are no-ops once m_shared_object is set, so this cannot free layers owned by another object.
+    clear_support_layers();
+    clear_layers();
     m_shared_object = object;
     BOOST_LOG_TRIVIAL(info) << __FUNCTION__ << boost::format(": this=%1%, found shared object from %2%")%this%m_shared_object;
 }
@@ -4329,9 +4334,9 @@ bool Print::is_dynamic_group_reorder() const
     return true;
 }
 
-int Print::get_filament_config_indx(int filament_id, int layer_id, bool use_cache)
+int Print::get_filament_config_indx(int filament_id, int layer_id)
 {
-    return get_config_index(filament_id, layer_id, m_config.filament_extruder_variant.values, m_filament_self_index, use_cache ? &m_filament_index_map : nullptr);
+    return get_config_index(filament_id, layer_id, m_config.filament_extruder_variant.values, m_filament_self_index, m_filament_index_map);
 }
 
 void Print::update_filament_self_index_cache()
@@ -4374,7 +4379,7 @@ int Print::get_nozzle_config_index(int filament_id, int layer_id)
     return get_config_index(filament_id, layer_id, m_default_region_config.print_extruder_variant.values, m_default_region_config.print_extruder_id.values, m_nozzle_index_map);
 }
 
-int Print::get_config_index(int filament_id, int layer_id, const std::vector<std::string> &variant_list, const std::vector<int>& self_index_list, FilamentIndexMap *index_map)
+int Print::get_config_index(int filament_id, int layer_id, const std::vector<std::string> &variant_list, const std::vector<int>& self_index_list, FilamentIndexMap &index_map)
 {
     auto group_result = get_layered_nozzle_group_result();
     // Orca: defensive — when no grouping producer has published a result yet, fall back to the
@@ -4385,8 +4390,7 @@ int Print::get_config_index(int filament_id, int layer_id, const std::vector<std
     if (!nozzle_info.has_value()) {
         // Orca: this fallback runs per-filament/per-layer in the g-code hot path — log once per filament
         // (reset each slice) instead of flooding thousands of identical lines that bury the real error.
-        // Without the cache, the log set is left alone too; the cached caller reports the same filament.
-        if (index_map && m_missing_nozzle_group_logged.insert(filament_id).second)
+        if (m_missing_nozzle_group_logged.insert(filament_id).second)
             BOOST_LOG_TRIVIAL(error) << __FUNCTION__
                                      << boost::format(", Line %1%: could not found group_nozzle_info corresponding to filament_id %2%, layer_id %3% (further occurrences for this filament suppressed)") % __LINE__ % filament_id %
                                             layer_id;
@@ -4395,17 +4399,15 @@ int Print::get_config_index(int filament_id, int layer_id, const std::vector<std
 
     ExtruderType     extruder_type      = ExtruderType(m_config.extruder_type.get_at(nozzle_info->extruder_id));
     NozzleVolumeType nozzle_volume_type = nozzle_info->volume_type;
-    if (!index_map)
-        return get_config_index_base(nozzle_volume_type, extruder_type, filament_id + 1, variant_list, self_index_list);
 
     FilamentIndexKey key{filament_id, extruder_type, nozzle_volume_type};
-    auto             iter = index_map->find(key);
-    if (iter == index_map->end()) {
+    auto             iter = index_map.find(key);
+    if (iter == index_map.end()) {
         int index = get_config_index_base(nozzle_volume_type, extruder_type, filament_id + 1, variant_list, self_index_list);
-        (*index_map)[key] = index;
+        index_map[key] = index;
         return index;
     } else {
-        return iter->second;
+        return index_map[key];
     }
 }
 

src/libslic3r/PrintObject.cpp

@@ -987,6 +987,9 @@ void PrintObject::generate_support_material()
             this->_generate_support_material();
             m_print->throw_if_canceled();
         }
+        // Orca: the tree support collision/avoidance caches and support nodes are only used while this step runs
+        // (detect_overhangs() rebuilds them from scratch), so don't keep them resident until the next slice.
+        this->clear_tree_support_preview_cache();
         this->set_done(posSupportMaterial);
     }
 }

src/libslic3r/PrintObjectSlice.cpp

@@ -1346,7 +1346,7 @@ void PrintObject::slice_volumes()
                         if (min_growth < 0.f || elfoot > 0.f) {
                             // Apply the negative XY compensation. (the ones that is <0)
                             ExPolygons trimming;
-                            static const float eps = float(scale_(m_config.slice_closing_radius.value) * 1.5);
+                            const float eps = float(scale_(m_config.slice_closing_radius.value) * 1.5);
                             if (elfoot > 0.f) {
                                 ExPolygons expolygons_to_compensate = offset_ex(layer->merged(eps), -eps);
                                 lslices_elfoot_uncompensated[layer_id] = expolygons_to_compensate;

src/libslic3r/Support/TreeSupport.cpp

@@ -1820,37 +1820,15 @@ coordf_t TreeSupport::get_radius(const SupportNode* node)
     return node->radius;
 }
 
-ExPolygons TreeSupport::get_avoidance(coordf_t radius, size_t obj_layer_nr)
+// Orca: these are hit up to several times per node per layer in drop_nodes(), so hand out a
+// reference into the TreeSupportData cache instead of copying the ExPolygons out of it.
+const ExPolygons& TreeSupport::get_avoidance(coordf_t radius, size_t obj_layer_nr)
 {
-#if USE_SUPPORT_3D
-    if (m_model_volumes) {
-        bool on_build_plate = m_object_config->support_on_build_plate_only.value;
-        const Polygons& avoid_polys = m_model_volumes->getAvoidance(radius, obj_layer_nr, TreeSupport3D::TreeModelVolumes::AvoidanceType::FastSafe, on_build_plate, true);
-        ExPolygons expolys;
-        for (auto& poly : avoid_polys)
-            expolys.emplace_back(std::move(poly));
-        return expolys;
-    }
-    return ExPolygons();
-#else
     return m_ts_data->get_avoidance(radius, obj_layer_nr);
-#endif
 }
-ExPolygons TreeSupport::get_collision(coordf_t radius, size_t layer_nr)
+const ExPolygons& TreeSupport::get_collision(coordf_t radius, size_t layer_nr)
 {
-#if USE_SUPPORT_3D
-    if (m_model_volumes) {
-        bool on_build_plate = m_object_config->support_on_build_plate_only.value;
-        const Polygons& collision_polys = m_model_volumes->getCollision(radius, layer_nr, true);
-        ExPolygons expolys;
-        for (auto& poly : collision_polys)
-            expolys.emplace_back(std::move(poly));
-        return expolys;
-    }
-#else
     return m_ts_data->get_collision(radius, layer_nr);
-#endif
-    return ExPolygons();
 }
 Polygons TreeSupport::get_collision_polys(coordf_t radius, size_t layer_nr)
 {
@@ -2639,7 +2617,11 @@ void TreeSupport::draw_circles()
 #endif  // SUPPORT_TREE_DEBUG_TO_SVG
 
     SupportLayerPtrs& ts_layers = m_object->support_layers();
-    auto iter = std::remove_if(ts_layers.begin(), ts_layers.end(), [](SupportLayer* ts_layer) { return ts_layer->height < EPSILON; });
+    // Orca: the vector owns its layers, so the dropped ones have to be deleted, not just unlinked.
+    // std::stable_partition (unlike std::remove_if) leaves exactly the dropped layers in the tail.
+    auto iter = std::stable_partition(ts_layers.begin(), ts_layers.end(), [](SupportLayer* ts_layer) { return ts_layer->height >= EPSILON; });
+    for (auto it = iter; it != ts_layers.end(); ++it)
+        delete *it;
     ts_layers.erase(iter, ts_layers.end());
     for (int layer_nr = 0; layer_nr < ts_layers.size(); layer_nr++) {
         ts_layers[layer_nr]->upper_layer = layer_nr != ts_layers.size() - 1 ? ts_layers[layer_nr + 1] : nullptr;
@@ -2882,7 +2864,7 @@ void TreeSupport::drop_nodes()
                     //Insert a completely new node and let both original nodes fade.
                     Point next_position = (node.position + neighbours[0]) / 2; //Average position of the two nodes.
                     coordf_t next_radius = calc_radius(node.dist_mm_to_top+height_next);
-                    auto avoid_layer = get_avoidance(next_radius, obj_layer_nr_next);
+                    const ExPolygons& avoid_layer = get_avoidance(next_radius, obj_layer_nr_next);
                     if (group_index == 0)
                     {
                         //Avoid collisions.
@@ -3069,7 +3051,7 @@ void TreeSupport::drop_nodes()
                 }
 #endif
                 coordf_t next_radius = calc_radius(node.dist_mm_to_top + height_next);
-                auto avoidance_next = get_avoidance(next_radius, obj_layer_nr_next);
+                const ExPolygons& avoidance_next = get_avoidance(next_radius, obj_layer_nr_next);
 
                 Point  to_outside         = projection_onto(avoidance_next, node.position);
                 Point  direction_to_outer = to_outside - node.position;
@@ -3123,7 +3105,7 @@ void TreeSupport::drop_nodes()
                         if (is_outside) { next_layer_vertex = candidate_vertex; }
                     }
                 }
-                auto              next_collision = get_collision(0, obj_layer_nr_next);
+                const ExPolygons& next_collision = get_collision(0, obj_layer_nr_next);
                 const bool   to_buildplate  = !is_inside_ex(m_ts_data->m_layer_outlines[obj_layer_nr_next], next_layer_vertex);
                 // don't increase radius if next node will collide partially with the object (STUDIO-7883)
                 to_outside             = projection_onto(next_collision, next_layer_vertex);

src/libslic3r/Support/TreeSupport.hpp

@@ -511,9 +511,9 @@ private:
     coordf_t calc_branch_radius(coordf_t base_radius, coordf_t mm_to_top, double diameter_angle_scale_factor, bool use_min_distance=true);
     coordf_t   calc_radius(coordf_t mm_to_top);
     coordf_t get_radius(const SupportNode* node);
-    ExPolygons get_avoidance(coordf_t radius, size_t obj_layer_nr);
+    const ExPolygons& get_avoidance(coordf_t radius, size_t obj_layer_nr);
     // layer's expolygon expanded by radius+m_xy_distance
-    ExPolygons get_collision(coordf_t radius, size_t layer_nr);
+    const ExPolygons& get_collision(coordf_t radius, size_t layer_nr);
     // get Polygons instead of ExPolygons
     Polygons get_collision_polys(coordf_t radius, size_t layer_nr);