修复:在无法加载材质时没有返回材质

src/Add-on/testEntity/ParseMaterialImage.ts

@@ -199,6 +199,8 @@ export async function ConverMaterial2(m: MeshPhongMaterial, url: string)
             mtl.envMap = exr;
             mtl.needsUpdate = true;
         });
+
+        return mtl;
     }
 }