Added sphere.center support to BufferGeometryLoader and BufferGeometryExporter. See #3748.

examples/js/exporters/BufferGeometryExporter.js

@@ -45,6 +45,7 @@ THREE.BufferGeometryExporter.prototype = {
 		if ( boundingSphere !== null ) {
 
 			output.boundingSphere = {
+				center: boundingSphere.center.toArray(),
 				radius: boundingSphere.radius
 			}
 

src/loaders/BufferGeometryLoader.js

@@ -59,7 +59,7 @@ THREE.BufferGeometryLoader.prototype = {
 
 		if ( boundingSphere !== undefined ) {
 
-			geometry.boundingSphere = new THREE.Sphere( undefined, boundingSphere.radius );
+			geometry.boundingSphere = new THREE.Sphere( boundingSphere.center, boundingSphere.radius );
 
 		}