From a26b02a4f007be8fa9a461912df979d235001a76 Mon Sep 17 00:00:00 2001
From: Stewart Allen <stewart.allen@gmail.com>
Date: Sun, 22 Mar 2020 20:05:04 -0400
Subject: [PATCH] cull polish lines under model

---
 js/geo-point.js       |  4 ++++
 js/kiri-driver-fdm.js | 30 +++++++++++++++++++++++++++---
 js/kiri-slicer.js     | 13 ++++++++-----
 3 files changed, 39 insertions(+), 8 deletions(-)

diff --git a/js/geo-point.js b/js/geo-point.js
index 71623152..62e68333 100644
--- a/js/geo-point.js
+++ b/js/geo-point.js
@@ -318,6 +318,10 @@ var gs_base_point = exports;
         return BASE.newLine(np1, np2, KEYS.NONE);
     };
 
+    PRO.offset = function(x, y, z) {
+        return newPoint(this.x + x, this.y + y, this.z + z);
+    };
+
     /**
      * checks if a point is inside of a polygon
      * does not check children/holes
diff --git a/js/kiri-driver-fdm.js b/js/kiri-driver-fdm.js
index fe723b26..3562fa99 100644
--- a/js/kiri-driver-fdm.js
+++ b/js/kiri-driver-fdm.js
@@ -221,21 +221,45 @@ var gs_kiri_fdm = exports;
 
                         let polys = [];
                         pa.forEach(p => {
+                            // rotate and test for self-intersection (points under model)
+                            p.ensureXY();
+                            let ox = p._aligned == 'yz' ? 0.1 : 0;
+                            let oy = p._aligned == 'yz' ? 0 : 0.1;
+                            p.forEachPoint(pt => {
+                                let int = p.intersections(
+                                    pt.offset(ox,oy,0),
+                                    pt.offset(ox*10000,oy*10000,0));
+                                if (int.length > 0) {
+                                    pt._under = true;
+                                }
+                            });
+                            p.restoreXY();
+
                             let lastp = undefined;
                             let poly = [];
+                            // look for qualifying segments
                             p.forEachSegment((p1, p2) => {
-                                // return when both below
+                                // eliminate segments that projected up
+                                // intersect with the polygon (bottom faces)
+                                if (p1._under || p2._under) {
+                                    return;
+                                }
+                                // skip when both below layer range
                                 if (p1.z < zb && p2.z < zb) {
                                     return;
                                 }
-                                // return when both above
+                                // skip when both above layer range
                                 if (p1.z > zt && p2.z > zt) {
                                     return;
                                 }
-                                // return when vertical
+                                // skip vertical
                                 if (p1.x === p2.x && p1.y === p2.y) {
                                     return;
                                 }
+                                // skip horizontal
+                                // if (p1.z === p2.z) {
+                                //     return;
+                                // }
                                 // order points lowest to highest
                                 let swap = false;
                                 if (p1.z > p2.z) {
diff --git a/js/kiri-slicer.js b/js/kiri-slicer.js
index d4f82774..ea900ac1 100644
--- a/js/kiri-slicer.js
+++ b/js/kiri-slicer.js
@@ -11,7 +11,8 @@ var gs_kiri_slicer = exports;
 
     var slicer = self.kiri.slicer = {
         slice: slice,
-        sliceWidget: sliceWidget
+        sliceWidget: sliceWidget,
+        connectLines: connectLines
     };
 
     var KIRI = self.kiri,
@@ -489,11 +490,13 @@ var gs_kiri_slicer = exports;
                 if (topoMode) {
                     var lines = slice.lines, llen = lines.length, idx, line;
                     // shared points causing problems
-                    for (idx=0; idx<llen; idx++) { line = lines[idx];
+                    for (idx=0; idx<llen; idx++) {
+                        line = lines[idx];
                         line.p1 = line.p1.clone();
                         line.p2 = line.p2.clone();
                     }
-                    for (idx=0; idx<llen; idx++) { line = lines[idx];
+                    for (idx=0; idx<llen; idx++) {
+                        line = lines[idx];
                         if (options.swapX) {
                             line.p1.swapXZ();
                             line.p2.swapXZ();
@@ -535,7 +538,7 @@ var gs_kiri_slicer = exports;
      * @param {number} [index]
      * @returns {Array}
      */
-    function connectLines(input, index) {
+    function connectLines(input) {
         // map points to all other points they're connected to
         var DBUG = BASE.debug,
             CONF = BASE.config,
@@ -653,7 +656,7 @@ var gs_kiri_slicer = exports;
                 closed = 0,
                 open = 0;
 
-            paths.forEach(function(path, index) {
+            paths.forEach(function(path) {
                 // use longest perimeter vs longest path?
                 if (!longest || path.length > longest.length) longest = path;
                 if (!path.open) closed++; else open++;