fix: fallback to full download on HTTP range request failure

Author: Deyang-Dai

src/model/modelLoader.ts

@@ -17,6 +17,7 @@
 import '@babylonjs/core/Materials/Textures/Loaders/basisTextureLoader';
 import '@babylonjs/core/Materials/Textures/Loaders/ktxTextureLoader';
 import '@babylonjs/loaders/glTF';
+import { AssetContainer } from '@babylonjs/core/assetContainer';
 import { LoadAssetContainerAsync, LoadAssetContainerOptions } from '@babylonjs/core/Loading/sceneLoader';
 import { AbstractMesh } from '@babylonjs/core/Meshes/abstractMesh';
 import { IDisposable } from '@babylonjs/core/scene';
@@ -121,7 +122,18 @@ export class ModelLoader implements IDisposable {
             this._sceneManager.scene.getEngine().displayLoadingUI();
         }
 
-        const container = await LoadAssetContainerAsync(url, this._sceneManager.scene, loadAssetContainerOptions);
+        let container: AssetContainer;
+        try {
+            container = await LoadAssetContainerAsync(url, this._sceneManager.scene, loadAssetContainerOptions);
+        } catch (error) {
+            // Fallback to full download on range request failure
+            if (error instanceof Error && error.message.includes('RangeError')) {
+                loadAssetContainerOptions.pluginOptions!.gltf!.useRangeRequests = false;
+                container = await LoadAssetContainerAsync(url, this._sceneManager.scene, loadAssetContainerOptions);
+            } else {
+                throw error;
+            }
+        }
 
         // Add everything from the container into the scene
         container.addAllToScene();

test/model/modelLoader.test.ts

@@ -46,6 +46,7 @@ describe('ModelLoader', () => {
     });
 
     afterEach(() => {
+        nock.cleanAll();
         modelLoader?.dispose();
         sceneManager?.dispose();
         observableManager?.dispose();
@@ -89,6 +90,22 @@ describe('ModelLoader', () => {
         await modelLoader?.loadGltf('http://localhost/public/model/mannequin.glb', true);
 
         expect(sceneManager?.models.size).toBe(1);
-        nock.restore();
+    });
+
+    it('should be able to load glb asset with full download when HTTP range requests failed', async () => {
+        const data = fs.readFileSync('public/model/mannequin.glb');
+        nock('http://localhost')
+            .get('/public/model/mannequin.glb')
+            .matchHeader('range', 'bytes=0-19')
+            .reply(206, Buffer.from(''), {
+                'content-Range': 'bytes 0-19/760664',
+                'content-length': '20',
+            })
+            .get('/public/model/mannequin.glb')
+            .reply(200, data);
+
+        await modelLoader?.loadGltf('http://localhost/public/model/mannequin.glb', true);
+
+        expect(sceneManager?.models.size).toBe(1);
     });
 });