Bug fix for #78

Simple logic error in choosing which coords to split on if multiple intersections are detected for a segment and the segments already in the sweep line tree. Fixes #78
mfogel · Aug 15, 2019 · e7ab60d · e7ab60d
1 parent f5ad4f2
commit e7ab60d
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Showing 3 changed files with 54 additions and 4 deletions.
diff --git a/src/sweep-line.js b/src/sweep-line.js
@@ -104,10 +104,7 @@ export default class SweepLine {
         else if (nextMySplitter === null) mySplitter = prevMySplitter
         else {
           const cmpSplitters = SweepEvent.comparePoints(prevMySplitter, nextMySplitter)
-          if (cmpSplitters < 0) mySplitter = prevMySplitter
-          if (cmpSplitters > 0) mySplitter = nextMySplitter
-          // the two splitters are the exact same point
-          mySplitter = prevMySplitter
+          mySplitter = cmpSplitters <= 0 ? prevMySplitter : nextMySplitter
         }
 
         // Rounding errors can cause changes in ordering,

diff --git a/test/end-to-end/issue-78/args.geojson b/test/end-to-end/issue-78/args.geojson
@@ -0,0 +1,36 @@
+{
+  "type": "FeatureCollection",
+  "features": [
+    {
+      "type": "Feature",
+      "geometry": {
+        "type": "Polygon",
+        "coordinates": [
+          [
+            [-82.52799529864927, -143.1018307843396],
+            [-39.904413323673744, -30.14375420418703],
+            [82.49764582921772, -8.0378271183787],
+            [16.44517814188868, 28.188158503711254],
+            [-82.52799529864927, -143.1018307843396]
+          ]
+        ]
+      },
+      "properties": {}
+    },
+    {
+      "type": "Feature",
+      "geometry": {
+        "type": "Polygon",
+        "coordinates": [
+          [
+            [63.87786163053483, 190.5605341685717],
+            [-162.9109514965066, 149.5091687360925],
+            [-15.098334958220487, -25.754406771652196],
+            [63.87786163053483, 190.5605341685717]
+          ]
+        ]
+      },
+      "properties": {}
+    }
+  ]
+}
diff --git a/test/end-to-end/issue-78/intersection.geojson b/test/end-to-end/issue-78/intersection.geojson
@@ -0,0 +1,17 @@
+{
+  "type": "Feature",
+  "properties": {},
+  "geometry": {
+    "type": "MultiPolygon",
+    "coordinates": [
+      [
+        [
+          [-15.16468395703966, -25.67573579594832],
+          [-15.098334958220487, -25.754406771652196],
+          [-15.062901059213404, -25.657353708804518],
+          [-15.16468395703966, -25.67573579594832]
+        ]
+      ]
+    ]
+  }
+}