Switch to dynamic import to load meshopt_decoder module

Playground/index-local.html

@@ -59,8 +59,9 @@
             BABYLONDEVTOOLS.Loader       
                 .require("index.js")
                 .load(() => {
+                    BABYLON.GLTF2.Loader.Extensions.EXT_meshopt_compression.DecoderPath = "../dist/preview%20release/meshopt_decoder.module.js";
                 });
         </script>
     </body>
 
-</html>
+</html>

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

@@ -3,8 +3,6 @@ import { IGLTFLoaderExtension } from "../glTFLoaderExtension";
 import { GLTFLoader } from "../glTFLoader";
 import { IBufferView } from "../glTFLoaderInterfaces";
 
-import { MeshoptDecoder } from "./meshopt_decoder.module.js";
-
 const NAME = "EXT_meshopt_compression";
 
 /**
@@ -23,12 +21,28 @@ export class EXT_meshopt_compression implements IGLTFLoaderExtension {
      */
     public enabled: boolean;
 
+    /**
+     * Path to decoder module; defaults to https://preview.babylonjs.com/meshopt_decoder.module.js
+     */
+    public static DecoderPath: string = "https://preview.babylonjs.com/meshopt_decoder.module.js";
+
     private _loader: GLTFLoader;
+    private _decoder: Promise<any>;
 
     /** @hidden */
     constructor(loader: GLTFLoader) {
-        this.enabled = loader.isExtensionUsed(NAME) && MeshoptDecoder.supported;
+        this.enabled = loader.isExtensionUsed(NAME);
         this._loader = loader;
+
+        if (this.enabled) {
+            var url = EXT_meshopt_compression.DecoderPath;
+
+            this._decoder = import(/* webpackIgnore: true */ url).then(function (result) {
+                // Wait for WebAssembly compilation before resolving promise
+                var MeshoptDecoder = result.MeshoptDecoder;
+                return MeshoptDecoder.ready.then(() => MeshoptDecoder);
+            });
+        }
     }
 
     /** @hidden */
@@ -44,10 +58,10 @@ export class EXT_meshopt_compression implements IGLTFLoaderExtension {
             }
 
             var view = this._loader.loadBufferViewAsync(context, extensionDef);
-            var decoder = MeshoptDecoder;
 
-            extensionDef._decoded = Promise.all([view, decoder.ready]).then(function (res) {
+            extensionDef._decoded = Promise.all([view, this._decoder]).then(function (res) {
                 var source = res[0] as Uint8Array;
+                var decoder = res[1];
                 var count = extensionDef.count;
                 var stride = extensionDef.byteStride;
                 var result = new Uint8Array(new ArrayBuffer(count * stride));

loaders/src/glTF/2.0/Extensions/meshopt_decoder.module.d.ts

@@ -1,11 +0,0 @@
-// This file is part of meshoptimizer library and is distributed under the terms of MIT License.
-// Copyright (C) 2016-2020, by Arseny Kapoulkine (arseny.kapoulkine@gmail.com)
-export const MeshoptDecoder: {
-    supported: boolean;
-    ready: Promise<void>;
-
-    decodeVertexBuffer: (target: Uint8Array, count: number, size: number, source: Uint8Array, filter?: string) => void;
-    decodeIndexBuffer: (target: Uint8Array, count: number, size: number, source: Uint8Array) => void;
-    decodeIndexSequence: (target: Uint8Array, count: number, size: number, source: Uint8Array) => void;
-    decodeGltfBuffer: (target: Uint8Array, count: number, size: number, source: Uint8Array, mode: string, filter?: string) => void;
-};