在BabylonJS中加载glTF-Transform处理的Draco压缩网格报错

• 需求场景：加载通过REST请求动态获取、经glTF-Transform服务端处理的Draco压缩网格，该网格以内存Blob形式存在。由于URL.createObjectURL生成的URL无法指定扩展名，直接调用SceneLoader.ImportMeshAsync导入会报错：

createModelRenderable.ts:520 Error during loading meshes, try again RuntimeError: Unable to load from blob:http://127.0.0.1:5173/b3b55baa-4ede-41fd-a66e-304460969a7f: importMesh of undefined from undefined version: undefined, exporter version: undefinedimportMesh has failed JSON parse
    at A (sceneLoader.js:343:46)
    at Object.importMesh (babylonFileLoader.js:797:17)
    at sceneLoader.js:382:35
    at A (sceneLoader.js:182:13)
    at fileTools.js:375:9
    at XMLHttpRequest.A (fileTools.js:489:33)

注：此情况下普通.glb文件也无法加载

• 为解决扩展名问题，将ImportMeshAsync的pluginExtension参数指定为.glb后，普通GLB可正常加载，但Draco压缩网格仍加载失败，报错：

createModelRenderable.ts:519 Error during loading meshes, try again RuntimeError: Unable to load from blob:http://127.0.0.1:5173/07f9e64c-2c58-4c64-81c0-54f7d3bbb586: (this.dracoCompression || E8.Default)._decodeMeshToGeometryForGltfAsync is not a function
    at A (sceneLoader.js:343:46)
    at sceneLoader.js:397:21

• 已确认KHR_draco_mesh_compression扩展加载正常（重复添加会提示已存在），Draco配置指向有效CDN：

wasmUrl: "https://preview.babylonjs.com/draco_wasm_wrapper_gltf.js"
wasmBinaryUrl: "https://preview.babylonjs.com/draco_decoder_gltf.wasm"
fallbackUrl: "https://preview.babylonjs.com/draco_decoder_gltf.js"

解码器WASM已正常下载，尝试使用本地文件也无效果；且该Draco压缩GLB文件可在Babylon沙箱正常加载。

• 尝试手动加载文件后解码，代码如下：

const loadFileAsync = function (url) {
  return new Promise(function (resolve, reject) {
    LoadFile(
      url,
      function (data) {
        resolve(data);
      },
      undefined,
      undefined,
      true,
      function (_request, exception) {
        reject(exception);
      }
    );
  });
};

调用new DracoCompression().decodeMeshAsync()解码时，得到错误提示：Not a Draco file.

• 目前BabylonJS论坛已有用户遇到相同问题，暂无可行解决方案。

内容的提问来源于stack exchange，提问作者Alessandro Muzzi