Merge branch 'master' into master

Author: Hannah

CHANGES.md

@@ -18,6 +18,7 @@ Change Log
 * Fixed an issue where scaling near zero with an model animation could cause rendering to stop. [#6954](https://github.com/AnalyticalGraphicsInc/cesium/pull/6954)
 * Fixed bug where credits weren't displaying correctly if more than one viewer was initialized [#6965](expect(https://github.com/AnalyticalGraphicsInc/cesium/issues/6965)
 * Fixed entity show issues. [#7048](https://github.com/AnalyticalGraphicsInc/cesium/issues/7048)
+* Fixed a bug where polylines on terrain covering very large portions of the globe would cull incorrectly in 3d-only scenes. [#7043](https://github.com/AnalyticalGraphicsInc/cesium/issues/7043)
 
 ### 1.49 - 2018-09-04
 

Source/Core/GroundPolylineGeometry.js

@@ -697,7 +697,6 @@ define([
     var normalNudgeScratch = new Cartesian3();
 
     var scratchBoundingSpheres = [new BoundingSphere(), new BoundingSphere()];
-    var boundingSphereCenterCartographicScratch = new Cartographic();
 
     // Winding order is reversed so each segment's volume is inside-out
     var REFERENCE_INDICES = [
@@ -1061,12 +1060,8 @@ define([
         BoundingSphere.fromVertices(topPositionsArray, Cartesian3.ZERO, 3, boundingSpheres[1]);
         var boundingSphere = BoundingSphere.fromBoundingSpheres(boundingSpheres);
 
-        // Adjust bounding sphere height and radius to cover whole volume
-        var midHeight = sumHeights / (segmentCount * 2.0);
-        var boundingSphereCenterCartographic = Cartographic.fromCartesian(boundingSphere.center, ellipsoid, boundingSphereCenterCartographicScratch);
-        boundingSphereCenterCartographic.height = midHeight;
-        boundingSphere.center = Cartographic.toCartesian(boundingSphereCenterCartographic, ellipsoid, boundingSphere.center);
-        boundingSphere.radius = Math.max(boundingSphere.radius, midHeight);
+        // Adjust bounding sphere height and radius to cover more of the volume
+        boundingSphere.radius += sumHeights / (segmentCount * 2.0);
 
         var attributes = {
             position : new GeometryAttribute({

Specs/Core/GroundPolylineGeometrySpec.js

@@ -555,6 +555,7 @@ defineSuite([
         var pointsDistance = Cartesian3.distance(positions[0], positions[1]);
 
         expect(boundingSphere.radius > pointsDistance).toBe(true);
+        expect(boundingSphere.radius > 1000.0).toBe(true); // starting top/bottom height
     });
 
     var packedInstance = [positions.length];