GLTFLoader: Support interleaved morph target accessors.

examples/js/loaders/GLTFLoader.js

@@ -1100,7 +1100,7 @@ THREE.GLTFLoader = ( function () {
 				// So morphTarget value will depend on mesh's position, then cloning attribute
 				// for the case if attribute is shared among two or more meshes.
 
-				positionAttribute = accessors[ target.POSITION ].clone();
+				positionAttribute = cloneBufferAttribute( accessors[ target.POSITION ] );
 				var position = geometry.attributes.position;
 
 				for ( var j = 0, jl = positionAttribute.count; j < jl; j ++ ) {
@@ -1118,7 +1118,7 @@ THREE.GLTFLoader = ( function () {
 
 				// Copying the original position not to affect the final position.
 				// See the formula above.
-				positionAttribute = geometry.attributes.position.clone();
+				positionAttribute = cloneBufferAttribute( geometry.attributes.position );
 
 			}
 
@@ -1135,7 +1135,7 @@ THREE.GLTFLoader = ( function () {
 
 				// see target.POSITION's comment
 
-				normalAttribute = accessors[ target.NORMAL ].clone();
+				normalAttribute = cloneBufferAttribute( accessors[ target.NORMAL ] );
 				var normal = geometry.attributes.normal;
 
 				for ( var j = 0, jl = normalAttribute.count; j < jl; j ++ ) {
@@ -1151,7 +1151,7 @@ THREE.GLTFLoader = ( function () {
 
 			} else if ( geometry.attributes.normal !== undefined ) {
 
-				normalAttribute = geometry.attributes.normal.clone();
+				normalAttribute = cloneBufferAttribute( geometry.attributes.normal );
 
 			}
 
@@ -1231,6 +1231,31 @@ THREE.GLTFLoader = ( function () {
 
 	}
 
+	function cloneBufferAttribute( attribute ) {
+
+		if ( attribute.isInterleavedBufferAttribute ) {
+
+			var count = attribute.count;
+			var itemSize = attribute.itemSize;
+			var array = attribute.array.slice( 0, count * itemSize );
+
+			for ( var i = 0; i < count; ++ i ) {
+
+				array[ i ] = attribute.getX( i );
+				if ( itemSize >= 2 ) array[ i + 1 ] = attribute.getY( i );
+				if ( itemSize >= 3 ) array[ i + 2 ] = attribute.getZ( i );
+				if ( itemSize >= 4 ) array[ i + 3 ] = attribute.getW( i );
+
+			}
+
+			return new THREE.BufferAttribute( array, itemSize, attribute.normalized );
+
+		}
+
+		return attribute.clone();
+
+	}
+
 	/* GLTF PARSER */
 
 	function GLTFParser( json, extensions, options ) {