Generate Coherent Rays Directly

TL;DR

This paper introduces a novel technique for generating coherent rays directly in path tracing by reusing directions, reducing overhead and improving performance compared to traditional reordering methods.

Contribution

The authors propose a direct coherent ray generation method with an interleaved reuse domain partition to enhance path tracing efficiency without reordering overhead.

Findings

Outperforms reordering methods in various scenes

Reduces overhead associated with ray reordering

Improves coherence and performance in path tracing

Abstract

The path tracing method generates incoherent rays by randomly sampling directions. This randomness makes it unsuitable for modern processor architectures that rely on coherence to achieve optimal performance. Many efforts have been made to address this issue by reordering rays based on their origin, end, or direction to enhance coherence. However, a drawback of reordering methods is the need to encode and sort rays before tracing, introducing additional overhead. We propose a technique to generate coherent rays directly by reusing the direction. Additionally, we introduce an interleaved reuse domain partition method to mitigate the impact of sampling correlation resulting from direction reuse. We demonstrate the effectiveness of our approach across various scenes, establishing its superiority over reordering methods.