medial axis optimisation

src/libslic3r/MedialAxis.cpp

@@ -20,6 +20,19 @@ namespace Slic3r {
 void
 MedialAxis::build(Polylines &polylines)
 {
+    //TODO: special case for triangles
+    //  take the longest edge
+    //  take the opposite vertex and get the otho dist
+    //  move the longest edge by X% that dist (depends on angle? from 1/2 to 1/4? or always 1/3?) use move dist as width
+    //  clip it and then enlarge it into anchor
+    //  note: ensure that if anchor is over only one edge, it's not the one choosen.
+
+    //TODO: special case for quasi-rectangle
+    //  take longest (not-anchor if any) edge
+    //  get mid-dist for each adjascent edge
+    //  use these point to get the line, with the mid-dist as widths.
+    //  enlarge it into anchor
+
     ThickPolylines tp;
     this->build(tp);
     polylines.insert(polylines.end(), tp.begin(), tp.end());
@@ -215,6 +228,10 @@ MedialAxis::validate_edge(const VD::edge_type* edge, Lines &lines, std::map<cons
         if (!this->expolygon.contains(line.a)) return false;
     } else {
         //test if  (!expolygon.contains(line))
+        //this if isn't perfect (the middle of the line may still be out of the polygon)
+        //but this edge-case shouldn't occur anyway, by the way the voronoi is built.
+        if (!expolygon.contains(line.a) || !expolygon.contains(line.b)) { //this if reduced diff_pl from 25% to 18% cpu usage
+            //this line can count for 25% of slicing time, if not enclosed in if
             Polylines external_bits = diff_pl(Polylines{ Polyline{ line.a, line.b } }, expolygon);
             if (!external_bits.empty()) {
                 //check if the bits that are not inside are under epsilon length
@@ -226,6 +243,7 @@ MedialAxis::validate_edge(const VD::edge_type* edge, Lines &lines, std::map<cons
                     return false;
             }
         }
+    }
     
     // retrieve the original line segments which generated the edge we're checking
     const VD::cell_type* cell_l = edge->cell();