heal polys before tracing

notes.md

@@ -54,7 +54,6 @@
 # CAM
 
 * `B` trace clear and follow need depth-first support
-* `B` trace follow open polys should "heal" if ends touch
 * `B` trace open polys are not wound consistently
 * `B` path routing with tabs sometimes makes no sense
 * `B` clicking on a pop-op should pin it until clicked or [esc]

src/mode/cam/ops.js

@@ -685,7 +685,7 @@
             let { op, state } = this;
             let { tool, rate, down, plunge, offset } = op;
             let { settings, widget, sliceAll, zMax, tabs } = state;
-            let { updateToolDiams, cutTabs, cutPolys } = state;
+            let { updateToolDiams, cutTabs, cutPolys, healPolys } = state;
             let { process, stock } = settings;
             // generate tracing offsets from chosen features
             let sliceOut = this.sliceOut = [];
@@ -744,6 +744,8 @@
                     .setLayer("clear", {line: 0xaa00aa}, false)
                     .addPolys(slice.camLines)
             }
+            // connect selected segments if open and touching
+            polys = healPolys(polys);
             switch (op.mode) {
                 case "follow":
                     for (let poly of polys) {

src/mode/cam/slice.js

@@ -106,6 +106,7 @@
             tabs,
             cutTabs,
             cutPolys,
+            healPolys,
             slicer,
             sliceAll,
             updateToolDiams,
@@ -273,8 +274,11 @@
 
     function cutPolys(polys, offset, z, inter) {
         let noff = [];
-        // tabs = tabs.filter(tab => z < tab.pos.z + tab.dim.z/2).map(tab => tab.off).flat();
         offset.forEach(op => noff.appendAll( op.cut(POLY.union(polys, 0, true), inter) ));
+        return healPolys(noff);
+    }
+
+    function healPolys(noff) {
         if (noff.length > 1) {
             let heal = 0;
             // heal/rejoin open segments that share endpoints
@@ -317,6 +321,14 @@
                 // cull nulls
                 noff = noff.filter(o => o);
             }
+            // close poly if head meets tail
+            for (let poly of noff) {
+                if (poly.open && poly.first().isMergable2D(poly.last())) {
+                    poly.points.pop();
+                    poly.length--;
+                    poly.open = false;
+                }
+            }
         }
         return noff;
     }