VIA: Visibility-aware Web-based Virtual Reality

Abstract

New standards such as WebXR enable cross-platform VR experiences, relying on the ubiquity of the modern web browser. However, upon measuring performance of WebXR scenes, we found users can suffer from high latency while waiting for all 3D objects appear in their field-of-view. This is because storage and fetching of 3D objects in WebXR (and its underlying WebGL libraries) are agnostic to the user's orientation and location, leading to latency issues. Specifically, fetching of texture files in arbitrary order results in 3D objects waiting on their texture dependencies, and the storage of all objects' geometry data in one large file blocks individual objects from rendering even if their texture dependencies are satisfied. To address these issues, we propose a systematic prioritization of which 3D objects and their dependencies should be fetched first, based on the user's position and orientation in the VR scene. To improve efficiency, the geometry data belonging to each 3D object are optimally grouped together to minimize the average latency. Our experiments with various WebXR scenes under different network conditions show that our scheme can significantly reduce the time to all 3D objects appearing in the user's field-of-view, by up to 50%, compared the default WebXR behavior.