From bef64ecec083a2c2e59bd18e373652c597bd6c35 Mon Sep 17 00:00:00 2001
From: tamasmeszaros <meszaros.q@gmail.com>
Date: Mon, 24 Oct 2022 15:20:45 +0200
Subject: [PATCH] Don't call search_ground_route for every ground point
 candidate

search_ground_route already tries to find a suitable ground point globally from the source. Different destination arguments will not help much but will cause a lot of redundant cpu burning

SPE-1303
---
 src/libslic3r/BranchingTree/BranchingTree.cpp |  2 +-
 src/libslic3r/BranchingTree/BranchingTree.hpp |  1 -
 src/libslic3r/SLA/BranchingTreeSLA.cpp        | 14 +++++++++++++-
 3 files changed, 14 insertions(+), 3 deletions(-)

diff --git a/src/libslic3r/BranchingTree/BranchingTree.cpp b/src/libslic3r/BranchingTree/BranchingTree.cpp
index 6463a30de..3e5e0a686 100644
--- a/src/libslic3r/BranchingTree/BranchingTree.cpp
+++ b/src/libslic3r/BranchingTree/BranchingTree.cpp
@@ -5,7 +5,7 @@
 #include <optional>
 #include <algorithm>
 
-#include "libslic3r/SLA/SupportTreeUtils.hpp"
+#include "libslic3r/TriangleMesh.hpp"
 
 namespace Slic3r { namespace branchingtree {
 
diff --git a/src/libslic3r/BranchingTree/BranchingTree.hpp b/src/libslic3r/BranchingTree/BranchingTree.hpp
index c88410b3a..b54d47ca2 100644
--- a/src/libslic3r/BranchingTree/BranchingTree.hpp
+++ b/src/libslic3r/BranchingTree/BranchingTree.hpp
@@ -5,7 +5,6 @@
 #include <admesh/stl.h>
 
 #include "libslic3r/ExPolygon.hpp"
-#include "libslic3r/BoundingBox.hpp"
 
 namespace Slic3r { namespace branchingtree {
 
diff --git a/src/libslic3r/SLA/BranchingTreeSLA.cpp b/src/libslic3r/SLA/BranchingTreeSLA.cpp
index 72314c9d8..59ec05113 100644
--- a/src/libslic3r/SLA/BranchingTreeSLA.cpp
+++ b/src/libslic3r/SLA/BranchingTreeSLA.cpp
@@ -18,6 +18,8 @@ class BranchingTreeBuilder: public branchingtree::Builder {
     const SupportableMesh  &m_sm;
     const branchingtree::PointCloud &m_cloud;
 
+    std::set<int /*ground node_id that was already processed*/> m_ground_mem;
+
     // Scaling of the input value 'widening_factor:<0, 1>' to produce resonable
     // widening behaviour
     static constexpr double WIDENING_SCALE = 0.02;
@@ -156,11 +158,21 @@ bool BranchingTreeBuilder::add_merger(const branchingtree::Node &node,
 bool BranchingTreeBuilder::add_ground_bridge(const branchingtree::Node &from,
                                              const branchingtree::Node &to)
 {
-    bool ret = search_ground_route(ex_tbb, m_builder, m_sm,
+    bool ret = false;
+
+    auto it = m_ground_mem.find(from.id);
+    if (it == m_ground_mem.end()) {
+        ret = search_ground_route(ex_tbb, m_builder, m_sm,
                                    sla::Junction{from.pos.cast<double>(),
                                                  get_radius(from)},
                                    get_radius(to)).first;
 
+        // Remember that this node was tested if can go to ground, don't
+        // test it with any other destination ground point because
+        // it is unlikely that search_ground_route would find a better solution
+        m_ground_mem.insert(from.id);
+    }
+
     if (ret) {
         build_subtree(from.id);
     }