ENH: speed gcode export up again

thanks prusa

Signed-off-by: salt.wei <salt.wei@bambulab.com>
Change-Id: Ifbe5e2ea55b16a7fe281b54ca16c37695c15f5b1

src/libslic3r/GCode/RetractWhenCrossingPerimeters.cpp

@@ -0,0 +1,54 @@
+#include "../ClipperUtils.hpp"
+#include "../Layer.hpp"
+#include "../Polyline.hpp"
+
+#include "RetractWhenCrossingPerimeters.hpp"
+
+namespace Slic3r {
+
+bool RetractWhenCrossingPerimeters::travel_inside_internal_regions(const Layer &layer, const Polyline &travel)
+{
+    if (m_layer != &layer) {
+        // Update cache.
+        m_layer = &layer;
+        m_internal_islands.clear();
+        m_aabbtree_internal_islands.clear();
+        // Collect expolygons of internal slices.
+        for (const LayerRegion *layerm : layer.regions())
+            for (const Surface &surface : layerm->get_slices_simplified().surfaces)
+                if (surface.is_internal())
+                    m_internal_islands.emplace_back(&surface.expolygon);
+        // Calculate bounding boxes of internal slices.
+        std::vector<AABBTreeIndirect::BoundingBoxWrapper> bboxes;
+        bboxes.reserve(m_internal_islands.size());
+        for (size_t i = 0; i < m_internal_islands.size(); ++ i)
+            bboxes.emplace_back(i, get_extents(*m_internal_islands[i]));
+        // Build AABB tree over bounding boxes of internal slices.
+        m_aabbtree_internal_islands.build_modify_input(bboxes);
+    }
+
+    BoundingBox           bbox_travel = get_extents(travel);
+    AABBTree::BoundingBox bbox_travel_eigen{ bbox_travel.min, bbox_travel.max };
+    int result = -1;
+    bbox_travel.offset(SCALED_EPSILON);
+    AABBTreeIndirect::traverse(m_aabbtree_internal_islands, 
+        [&bbox_travel_eigen](const AABBTree::Node &node) {
+            return bbox_travel_eigen.intersects(node.bbox);
+        },
+        [&travel, &bbox_travel, &result, &islands = m_internal_islands](const AABBTree::Node &node) {
+            assert(node.is_leaf());
+            assert(node.is_valid());
+            Polygons clipped = ClipperUtils::clip_clipper_polygons_with_subject_bbox(*islands[node.idx], bbox_travel);
+            if (diff_pl(travel, clipped).empty()) {
+                // Travel path is completely inside an "internal" island. Don't retract.
+                result = int(node.idx);
+                // Stop traversal.
+                return false;
+            }
+            // Continue traversal.
+            return true;
+        });
+    return result != -1;
+}
+
+} // namespace Slic3r