WIP TreeSupports:

1) Reworked the merging code to use an AABB tree for better locality.
   The old code sorted lexicographically, the new code splits bounding
   boxes by the longest axis.
2) Refactored to a functional style with better const correctness.
3) Reduced memory allocation pressure by replacing std::set with
   vectors, in place merging etc.

src/libslic3r/AABBTreeIndirect.hpp

@@ -83,6 +83,13 @@ public:
 	//        to split around.
 	template<typename SourceNode>
 	void build(std::vector<SourceNode> &&input)
+	{
+		this->build_modify_input(input);
+        input.clear();
+	}
+
+	template<typename SourceNode>
+	void build_modify_input(std::vector<SourceNode> &input)
 	{
         if (input.empty())
 			clear();
@@ -91,7 +98,6 @@ public:
             m_nodes.assign(next_highest_power_of_2(input.size()) * 2 - 1, Node());
             build_recursive(input, 0, 0, input.size() - 1);
 		}
-        input.clear();
 	}
 
 	const std::vector<Node>& 	nodes() const { return m_nodes; }

src/libslic3r/PrintObject.cpp

@@ -2198,8 +2198,7 @@ void PrintObject::combine_infill()
 void PrintObject::_generate_support_material()
 {
     if (m_config.support_material_style == smsTree) {
-        TreeSupport tree_support;
-        tree_support.generateSupportAreas(*this);
+        fff_tree_support_generate(*this, std::function<void()>([this](){ this->throw_if_canceled(); }));
     } else {
         PrintObjectSupportMaterial support_material(this, m_slicing_params);
         support_material.generate(*this);

src/libslic3r/TreeModelVolumes.cpp

@@ -23,7 +23,7 @@
 #include <tbb/parallel_for.h>
 #include <tbb/task_group.h>
 
-namespace Slic3r
+namespace Slic3r::FFFTreeSupport
 {
 
 // or warning
@@ -106,7 +106,10 @@ TreeModelVolumes::TreeModelVolumes(
     const PrintObject &print_object,
     const BuildVolume &build_volume,
     const coord_t max_move, const coord_t max_move_slow, size_t current_mesh_idx, 
-    double progress_multiplier, double progress_offset, const std::vector<Polygons>& additional_excluded_areas) :
+#ifdef SLIC3R_TREESUPPORTS_PROGRESS
+    double progress_multiplier, double progress_offset, 
+#endif // SLIC3R_TREESUPPORTS_PROGRESS
+    const std::vector<Polygons>& additional_excluded_areas) :
     // -2 to avoid rounding errors
     m_max_move{ std::max<coord_t>(max_move - 2, 0) }, m_max_move_slow{ std::max<coord_t>(max_move_slow - 2, 0) },
 #ifdef SLIC3R_TREESUPPORTS_PROGRESS
@@ -161,7 +164,7 @@ TreeModelVolumes::TreeModelVolumes(
         m_min_resolution = std::min(m_min_resolution, data_pair.first.resolution);
     }
 
-    const TreeSupport::TreeSupportSettings config{ m_layer_outlines[m_current_outline_idx].first };
+    const TreeSupportSettings config{ m_layer_outlines[m_current_outline_idx].first };
     m_current_min_xy_dist = config.xy_min_distance;
     m_current_min_xy_dist_delta = config.xy_distance - m_current_min_xy_dist;
     assert(m_current_min_xy_dist_delta >= 0);
@@ -206,7 +209,7 @@ void TreeModelVolumes::precalculate(const coord_t max_layer)
     // Get the config corresponding to one mesh that is in the current group. Which one has to be irrelevant.
     // Not the prettiest way to do this, but it ensures some calculations that may be a bit more complex
     // like inital layer diameter are only done in once.
-    TreeSupport::TreeSupportSettings config(m_layer_outlines[m_current_outline_idx].first);
+    TreeSupportSettings config(m_layer_outlines[m_current_outline_idx].first);
 
     {
         // calculate which radius each layer in the tip may have.
@@ -297,7 +300,7 @@ const Polygons& TreeModelVolumes::getCollision(const coord_t orig_radius, LayerI
         return (*result).get();
     if (m_precalculated) {
         BOOST_LOG_TRIVIAL(error_level_not_in_cache) << "Had to calculate collision at radius " << radius << " and layer " << layer_idx << ", but precalculate was called. Performance may suffer!";
-        TreeSupport::showError("Not precalculated Collision requested.", false);
+        tree_supports_show_error("Not precalculated Collision requested.", false);
     }
     const_cast<TreeModelVolumes*>(this)->calculateCollision(radius, layer_idx);
     return getCollision(orig_radius, layer_idx, min_xy_dist);
@@ -312,7 +315,7 @@ const Polygons& TreeModelVolumes::getCollisionHolefree(coord_t radius, LayerInde
         return (*result).get();
     if (m_precalculated) {
         BOOST_LOG_TRIVIAL(error_level_not_in_cache) << "Had to calculate collision holefree at radius " << radius << " and layer " << layer_idx << ", but precalculate was called. Performance may suffer!";
-        TreeSupport::showError("Not precalculated Holefree Collision requested.", false);
+        tree_supports_show_error("Not precalculated Holefree Collision requested.", false);
     }
     const_cast<TreeModelVolumes*>(this)->calculateCollisionHolefree({ radius, layer_idx });
     return getCollisionHolefree(radius, layer_idx);
@@ -336,10 +339,10 @@ const Polygons& TreeModelVolumes::getAvoidance(const coord_t orig_radius, LayerI
     if (m_precalculated) {
         if (to_model) {
             BOOST_LOG_TRIVIAL(error_level_not_in_cache) << "Had to calculate Avoidance to model at radius " << radius << " and layer " << layer_idx << ", but precalculate was called. Performance may suffer!";
-            TreeSupport::showError("Not precalculated Avoidance(to model) requested.", false);
+            tree_supports_show_error("Not precalculated Avoidance(to model) requested.", false);
         } else {
             BOOST_LOG_TRIVIAL(error_level_not_in_cache) << "Had to calculate Avoidance at radius " << radius << " and layer " << layer_idx << ", but precalculate was called. Performance may suffer!";
-            TreeSupport::showError("Not precalculated Avoidance(to buildplate) requested.", false);
+            tree_supports_show_error("Not precalculated Avoidance(to buildplate) requested.", false);
         }
     }
     const_cast<TreeModelVolumes*>(this)->calculateAvoidance({ radius, layer_idx }, ! to_model, to_model);
@@ -357,7 +360,7 @@ const Polygons& TreeModelVolumes::getPlaceableAreas(const coord_t orig_radius, L
         return (*result).get();
     if (m_precalculated) {
         BOOST_LOG_TRIVIAL(error_level_not_in_cache) << "Had to calculate Placeable Areas at radius " << radius << " and layer " << layer_idx << ", but precalculate was called. Performance may suffer!";
-        TreeSupport::showError("Not precalculated Placeable areas requested.", false);
+        tree_supports_show_error("Not precalculated Placeable areas requested.", false);
     }
     const_cast<TreeModelVolumes*>(this)->calculatePlaceables(radius, layer_idx);
     return getPlaceableAreas(orig_radius, layer_idx);
@@ -380,7 +383,7 @@ const Polygons& TreeModelVolumes::getWallRestriction(const coord_t orig_radius,
         return (*result).get();
     if (m_precalculated) {
         BOOST_LOG_TRIVIAL(error_level_not_in_cache) << "Had to calculate Wall restricions at radius " << radius << " and layer " << layer_idx << ", but precalculate was called. Performance may suffer!";
-        TreeSupport::showError(
+        tree_supports_show_error(
             min_xy_dist ? 
                 "Not precalculated Wall restriction of minimum xy distance requested )." :
                 "Not precalculated Wall restriction requested )."
@@ -774,4 +777,4 @@ coord_t TreeModelVolumes::ceilRadius(const coord_t radius) const
     return out;
 }
 
-}
+} // namespace Slic3r::FFFTreeSupport

src/libslic3r/TreeModelVolumes.hpp

@@ -22,11 +22,14 @@
 namespace Slic3r
 {
 
-using LayerIndex = int;
-
 class BuildVolume;
 class PrintObject;
 
+namespace FFFTreeSupport
+{
+
+using LayerIndex = int;
+
 struct TreeSupportMeshGroupSettings {
     TreeSupportMeshGroupSettings() = default;
     explicit TreeSupportMeshGroupSettings(const PrintObject &print_object);
@@ -194,15 +197,19 @@ class TreeModelVolumes
 public:
     TreeModelVolumes() = default;
     explicit TreeModelVolumes(const PrintObject &print_object, const BuildVolume &build_volume,
-        coord_t max_move, coord_t max_move_slow, size_t current_mesh_idx, double progress_multiplier, 
-        double progress_offset, const std::vector<Polygons> &additional_excluded_areas = {});
+        coord_t max_move, coord_t max_move_slow, size_t current_mesh_idx, 
+#ifdef SLIC3R_TREESUPPORTS_PROGRESS
+        double progress_multiplier, 
+        double progress_offset, 
+#endif // SLIC3R_TREESUPPORTS_PROGRESS
+        const std::vector<Polygons> &additional_excluded_areas = {});
     TreeModelVolumes(TreeModelVolumes&&) = default;
     TreeModelVolumes& operator=(TreeModelVolumes&&) = default;
 
     TreeModelVolumes(const TreeModelVolumes&) = delete;
     TreeModelVolumes& operator=(const TreeModelVolumes&) = delete;
 
-    enum class AvoidanceType
+    enum class AvoidanceType : int8_t
     {
         Slow,
         FastSafe,
@@ -605,6 +612,7 @@ private:
 #endif // SLIC3R_TREESUPPORTS_PROGRESS
 };
 
-}
+} // namespace FFFTreeSupport
+} // namespace Slic3r
 
 #endif //slic3r_TreeModelVolumes_hpp