Post0-VR: Enabling Universal Realistic Rendering for Modern VR via Exploiting Architectural Similarity and Data Sharing

To provide users with a fully immersive environment, VR post-processing, which adds numerous realistic effects on the frame after rendering, plays a key role in modern VR systems. Current post-processing is processed separately from normal rendering by the graphics processing unit (GPU). As a result, the GPU needs to first render a high-resolution frame and then add the post-processing effects within a very short time frame. Our in-depth experimental results on commercial VR products demonstrate that the post-processing in VR applications extends the VR frame time by approximately 2X on average. Furthermore, the ever-increasing resolution requirements of modern VR significantly increase the workloads for post-processing in the execution pipeline. This long delay causes VR real-time execution to frequently miss the critical frame-time deadline, thus hurting users' quality of experience.Based on the analysis of VR post-processing workflow and its common realistic effects, we observe that post-processing shares the same hardware pipeline with normal rendering, and even reuses the intermediate data produced by normal rendering. To fully utilize this hardware-level similarity and capture the data locality, we propose a novel universal realistic rendering architecture for VR, named Post0-VR, which eliminates post-processing by directly merging the common realistic effects into the normal rendering process. Based on our newly proposed VR architecture design, we further propose a dynamic accuracy adjustment method to simplify the normal rendering without hurting users' perception. The evaluation results on real-world applications demonstrate that Post0-VR can support different types of realistic effects while significantly improving the overall VR rendering performance.