GLTFLoader: Clean up.

examples/js/loaders/GLTFLoader.js

@@ -1346,34 +1346,21 @@ THREE.GLTFLoader = ( function () {
 
 			if ( hasMorphPosition ) {
 
-				// TODO: Error-prone use of a callback inside a loop.
-				var accessor = target.POSITION !== undefined
+				var pendingAccessor = target.POSITION !== undefined
 					? parser.getDependency( 'accessor', target.POSITION )
-						.then( function ( accessor ) {
-
-							// Cloning not to pollute original accessor below
-							return cloneBufferAttribute( accessor );
-
-						} )
 					: geometry.attributes.position;
 
-				pendingPositionAccessors.push( accessor );
+				pendingPositionAccessors.push( pendingAccessor );
 
 			}
 
 			if ( hasMorphNormal ) {
 
-				// TODO: Error-prone use of a callback inside a loop.
-				var accessor = target.NORMAL !== undefined
+				var pendingAccessor = target.NORMAL !== undefined
 					? parser.getDependency( 'accessor', target.NORMAL )
-						.then( function ( accessor ) {
-
-							return cloneBufferAttribute( accessor );
-
-						} )
 					: geometry.attributes.normal;
 
-				pendingNormalAccessors.push( accessor );
+				pendingNormalAccessors.push( pendingAccessor );
 
 			}
 
@@ -1387,6 +1374,24 @@ THREE.GLTFLoader = ( function () {
 			var morphPositions = accessors[ 0 ];
 			var morphNormals = accessors[ 1 ];
 
+			// Clone morph target accessors before modifying them.
+
+			for ( var i = 0, il = morphPositions.length; i < il; i ++ ) {
+
+				if ( geometry.attributes.position === morphPositions[ i ] ) continue;
+
+				morphPositions[ i ] = cloneBufferAttribute( morphPositions[ i ] );
+
+			}
+
+			for ( var i = 0, il = morphNormals.length; i < il; i ++ ) {
+
+				if ( geometry.attributes.normal === morphNormals[ i ] ) continue;
+
+				morphNormals[ i ] = cloneBufferAttribute( morphNormals[ i ] );
+
+			}
+
 			for ( var i = 0, il = targets.length; i < il; i ++ ) {
 
 				var target = targets[ i ];