Coherence and Adaptivity in Frameless Rendering-A Practical and Information Theoretic Analysis

Virtual and Augmented Reality applications demand low-latency rendering. Adaptive Frameless Rendering (AFR) techniques offer a potential alternative to currently dominating non-adaptive double-buffered real-time 3D rendering techniques. However, due to their adaptive non-contiguous importance sampling, AFR does not benefit fully from the performance improvements offered by caching the local scene information, resulting in a lower sampling rate. This article presents an experimental, followed by an information-theoretic analysis, of this coherence vs. adaptivity trade-off in AFR. It introduces a novel way to utilize entropy to evaluate the efficiency of a rendering technique. It also presents various spatial coherence exploiting techniques in 3D path tracing and their application to AFR, paving the way to future research in the field.