GLTFExporter: handle morph target attribute specially, per review comment

examples/js/exporters/GLTFExporter.js

@@ -1162,6 +1162,9 @@ THREE.GLTFExporter.prototype = {
 			var modifiedAttribute = null;
 			for ( var attributeName in geometry.attributes ) {
 
+				// Ignore morph target attributes, which are exported later.
+				if ( attributeName.substr( 0, 5 ) === 'morph' ) continue;
+
 				var attribute = geometry.attributes[ attributeName ];
 				attributeName = nameConversion[ attributeName ] || attributeName.toUpperCase();
 
@@ -1194,15 +1197,11 @@ THREE.GLTFExporter.prototype = {
 
 				}
 
-				if ( attributeName.substr( 0, 5 ) !== 'MORPH' ) {
-
-					var accessor = processAccessor( modifiedAttribute || attribute, geometry );
-					if ( accessor !== null ) {
+				var accessor = processAccessor( modifiedAttribute || attribute, geometry );
+				if ( accessor !== null ) {
 
-						attributes[ attributeName ] = accessor;
-						cachedData.attributes.set( attribute, accessor );
-
-					}
+					attributes[ attributeName ] = accessor;
+					cachedData.attributes.set( attribute, accessor );
 
 				}