handle adjacent positions that would be identical when squashed to lat/long

Author: likangning93

Source/Core/GroundPolylineGeometry.js

@@ -407,7 +407,7 @@ define([
         var index;
         var i;
 
-        var positions = arrayRemoveDuplicates(groundPolylineGeometry._positions, Cartesian3.equalsEpsilon);
+        var positions = groundPolylineGeometry._positions;
         var positionsLength = positions.length;
 
         if (positionsLength === 2) {
@@ -453,6 +453,10 @@ define([
             cartographics[i] = cartographic;
         }
 
+        // Remove duplicates
+        cartographics = arrayRemoveDuplicates(cartographics, Cartographic.equalsEpsilon);
+        cartographicsLength = cartographics.length;
+
         /**** Build heap-side arrays for positions, interpolated cartographics, and normals from which to compute vertices ****/
         // We build a "wall" and then decompose it into separately connected component "volumes" because we need a lot
         // of information about the wall. Also, this simplifies interpolation.

Specs/Core/GroundPolylineGeometrySpec.js

@@ -216,14 +216,15 @@ defineSuite([
         expect(geometry.attributes.texcoordNormalization2D).not.toBeDefined();
     });
 
-    it('removes adjacent duplicate positions', function() {
+    it('removes adjacent positions with the same latitude/longitude', function() {
         var startCartographic = Cartographic.fromDegrees(0.01, 0.0);
         var endCartographic = Cartographic.fromDegrees(0.02, 0.0);
         var groundPolylineGeometry = new GroundPolylineGeometry({
-            positions : Cartesian3.fromRadiansArray([
-                startCartographic.longitude, startCartographic.latitude,
-                endCartographic.longitude, endCartographic.latitude,
-                endCartographic.longitude, endCartographic.latitude
+            positions : Cartesian3.fromRadiansArrayHeights([
+                startCartographic.longitude, startCartographic.latitude, 0.0,
+                endCartographic.longitude, endCartographic.latitude, 0.0,
+                endCartographic.longitude, endCartographic.latitude, 0.0,
+                endCartographic.longitude, endCartographic.latitude, 10.0
             ]),
             granularity : 0.0
         });