Fix issue when multiple nodes point to the same mesh

loaders/src/glTF/2.0/Extensions/KHR_draco_mesh_compression.ts

@@ -14,7 +14,7 @@ module BABYLON.GLTF2.Extensions {
         public readonly name = NAME;
 
         protected _loadVertexDataAsync(context: string, primitive: ILoaderMeshPrimitive, babylonMesh: Mesh): Nullable<Promise<VertexData>> {
-            return this._loadExtensionAsync<IKHRDracoMeshCompression, VertexData>(context, primitive, (context, extension) => {
+            return this._loadExtensionAsync<IKHRDracoMeshCompression, VertexData>(context, primitive, (extensionContext, extension) => {
                 if (primitive.mode != undefined) {
                     if (primitive.mode !== MeshPrimitiveMode.TRIANGLE_STRIP &&
                         primitive.mode !== MeshPrimitiveMode.TRIANGLES) {
@@ -51,7 +51,7 @@ module BABYLON.GLTF2.Extensions {
                 loadAttribute("WEIGHTS_0", VertexBuffer.MatricesWeightsKind);
                 loadAttribute("COLOR_0", VertexBuffer.ColorKind);
 
-                var bufferView = GLTFLoader._GetProperty(context, this._loader._gltf.bufferViews, extension.bufferView);
+                var bufferView = GLTFLoader._GetProperty(extensionContext, this._loader._gltf.bufferViews, extension.bufferView);
                 return this._loader._loadBufferViewAsync(`#/bufferViews/${bufferView._index}`, bufferView).then(data => {
                     try {
                         return DracoCompression.Decode(data, attributes);

loaders/src/glTF/2.0/babylon.glTFLoaderExtension.ts

@@ -46,12 +46,13 @@ module BABYLON.GLTF2 {
             // Clear out the extension before executing the action to avoid recursing into the same property.
             delete extensions[this.name];
 
-            return actionAsync(context + "/extensions/" + this.name, extension).then(result => {
-                // Restore the extension after completing the action.
+            try {
+                return actionAsync(context + "/extensions/" + this.name, extension);
+            }
+            finally {
+                // Restore the extension after executing the action.
                 extensions[this.name] = extension;
-
-                return result;
-            });
+            }
         }
 
         /** Helper method called by the loader to allow extensions to override loading scenes. */