Ordered Front-to-back Any-Hit Traversal in RTX

TL;DR

This paper addresses the problem of ordered front-to-back any-hit traversal in ray tracing, proposing multiple solutions compatible with existing pipelines and evaluating their effectiveness.

Contribution

It introduces several methods for ordered front-to-back traversal in ray tracing and assesses their performance within current rendering pipelines.

Findings

Multiple solutions for ordered front-to-back traversal are proposed.

The solutions are evaluated within existing ray tracing pipelines.

The paper demonstrates the feasibility of implementing ordered traversal without skipping intersections.

Abstract

We look at the problem of Ordered Front-To-Back Any-Hit Traversal (FTB); i.e., a traversal that iterates through successive hits along a ray in a guaranteed front to back-sorted order, and without skip- ping any intersections even if they occur at the same distance. We describe multiple different ways of solving this problem within the constraints of the existing ray tracing pipeline, and evaluate the different realizations.