World-Space Direct and Indirect Lighting Sample Reuse with Persistent Reservoirs
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Date
2025
Journal Title
Journal ISSN
Volume Title
Publisher
The Eurographics Association
Abstract
In the context of hardware-accelerated real-time ray tracing, existing spatiotemporal resampling techniques are still constrained by screen-space dependencies, which may lead to reuse failures. To address this issue, we propose a world-space resampling method based on a hybrid spatial structure that combines uniform grids and octrees. This persistent structure, which remains unchanged with respect to camera motion, can efficiently partition scenes while preserving geometric details. Our method begins with generating initial light samples, then remaps these samples to the spatial structure. Spatial reuse occurs entirely within individual spatial nodes. For direct illumination, we determine the spatial node of each shading point and select the world-space reservoir from that node to obtain a light sample. For indirect illumination, we trace a BRDF ray and use the world-space reservoir within the spatial node at the hit point to improve the NEE. This unified approach enables joint sample reuse for both direct and indirect illumination. Our experiments show that the proposed method achieves 20-70% reduction in RelMSE compared to screen-space ReSTIR and previous world-space methods under equal-time comparison, with 2× faster convergence rates and superior temporal stability under rapid camera motion.
Description
CCS Concepts: Computing methodologies → Rendering;Ray tracing
@inproceedings{10.2312:pg.20251292,
booktitle = {Pacific Graphics Conference Papers, Posters, and Demos},
editor = {Christie, Marc and Han, Ping-Hsuan and Lin, Shih-Syun and Pietroni, Nico and Schneider, Teseo and Tsai, Hsin-Ruey and Wang, Yu-Shuen and Zhang, Eugene},
title = {{World-Space Direct and Indirect Lighting Sample Reuse with Persistent Reservoirs}},
author = {Yuan, JunPing and Wang, Chen and Sun, Qi and Guo, Jie and Bei, Jia and Zhang, Yan and Guo, Yanwen},
year = {2025},
publisher = {The Eurographics Association},
ISBN = {978-3-03868-295-0},
DOI = {10.2312/pg.20251292}
}