Merge pull request #6693 from likangning93/polylinesOnTerrainCheckDuplicates

check for adjacent duplicate positions in GroundPolylineGeometry

Author: bagnell

Source/Core/GroundPolylineGeometry.js

@@ -1,5 +1,6 @@
 define([
         './ApproximateTerrainHeights',
+        './arrayRemoveDuplicates',
         './BoundingSphere',
         './Cartesian3',
         './Cartographic',
@@ -24,6 +25,7 @@ define([
         './WebMercatorProjection'
     ], function(
         ApproximateTerrainHeights,
+        arrayRemoveDuplicates,
         BoundingSphere,
         Cartesian3,
         Cartographic,
@@ -451,6 +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

@@ -216,6 +216,25 @@ defineSuite([
         expect(geometry.attributes.texcoordNormalization2D).not.toBeDefined();
     });
 
+    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.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
+        });
+
+        var geometry = GroundPolylineGeometry.createGeometry(groundPolylineGeometry);
+
+        expect(geometry.indices.length).toEqual(36);
+        expect(geometry.attributes.position.values.length).toEqual(24);
+    });
+
     it('miters turns', function() {
         var groundPolylineGeometry = new GroundPolylineGeometry({
             positions : Cartesian3.fromDegreesArray([