Merge pull request #8482 from AnalyticalGraphicsInc/boundingSpherePro…

…jectTo2DZeroFix Fixed crash when BoundingSphere.projectTo2D is called on a BoundingSphere centered at the origin
CesiumGS · Jan 6, 2020 · b5943bc · b5943bc
2 parents 215a588 + 07874ac
commit b5943bc
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diff --git a/CHANGES.md b/CHANGES.md
@@ -6,6 +6,7 @@ Change Log
 ##### Additions :tada:
 
 * Added `Globe.showSkirts` to support the ability to hide terrain skirts when viewing terrain from below the surface. [#8489](https://github.com/AnalyticalGraphicsInc/cesium/pull/8489)
+* Fixed `BoundingSphere.projectTo2D` when the bounding sphere’s center is at the origin. [#8482](https://github.com/AnalyticalGraphicsInc/cesium/pull/8482)
 
 ##### Fixes :wrench:
 * Fixed a bug where the camera could go underground during mouse navigation. [#8504](https://github.com/AnalyticalGraphicsInc/cesium/pull/8504)

diff --git a/Source/Core/BoundingSphere.js b/Source/Core/BoundingSphere.js
@@ -1101,7 +1101,14 @@ import Rectangle from './Rectangle.js';
         var center = sphere.center;
         var radius = sphere.radius;
 
-        var normal = ellipsoid.geodeticSurfaceNormal(center, projectTo2DNormalScratch);
+        var normal;
+        if (Cartesian3.equals(center, Cartesian3.ZERO)) {
+            // Bounding sphere is at the center. The geodetic surface normal is not
+            // defined here so pick the x-axis as a fallback.
+            normal = Cartesian3.clone(Cartesian3.UNIT_X, projectTo2DNormalScratch);
+        } else {
+            normal = ellipsoid.geodeticSurfaceNormal(center, projectTo2DNormalScratch);
+        }
         var east = Cartesian3.cross(Cartesian3.UNIT_Z, normal, projectTo2DEastScratch);
         Cartesian3.normalize(east, east);
         var north = Cartesian3.cross(normal, east, projectTo2DNorthScratch);