VIA: Visibility-aware Web-based Virtual Reality
VIA: Visibility-aware Web-based Virtual Reality
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DOI：
10.1145/3485444.3487641
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发表时间：
2021-11
期刊：
影响因子：
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通讯作者：
Carter Slocum;Jingwen Huang;Jiasi Chen
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文献类型：
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作者：
Carter Slocum;Jingwen Huang;Jiasi Chen
诸如WebXR等新标准能够实现跨平台的虚拟现实体验，这依赖于现代网络浏览器的普及。然而，在对WebXR场景的性能进行测量时，我们发现用户在等待所有3D对象出现在其视野中时可能会遭受高延迟。这是因为在WebXR（及其底层的WebGL库）中，3D对象的存储和获取与用户的方向和位置无关，从而导致了延迟问题。具体来说，纹理文件的无序获取导致3D对象等待其纹理依赖项，并且将所有对象的几何数据存储在一个大文件中，即使其纹理依赖项已满足，也会阻碍单个对象的渲染。为了解决这些问题，我们提出根据用户在虚拟现实场景中的位置和方向，对哪些3D对象及其依赖项应首先获取进行系统性的优先级排序。为了提高效率，将属于每个3D对象的几何数据进行最优分组，以最小化平均延迟。我们在不同网络条件下对各种WebXR场景进行的实验表明，与默认的WebXR行为相比，我们的方案可以显著减少所有3D对象出现在用户视野中的时间，最多可减少50%。
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.