Title:	Dynamic Many-Light Importance Sampling for Real-Time Ray Tracing
Authors:	Freire, Pedro da Silva Pereira, João Madeiras
Citation:	WSCG 2024: full papers proceedings: 32. International Conference in Central Europe on Computer Graphics, Visualization and Computer Vision, p. 403-406.
Issue Date:	2024
Publisher:	Václav Skala - UNION Agency
Document type:	konferenční příspěvek conferenceObject
URI:	http://hdl.handle.net/11025/57416
ISSN:	2464–4625 (online) 2464–4617 (print)
Keywords:	sledování paprsků;ohraničující objemové hierarchie;Vulkan;osvětlení;urychlovací struktury;vzorkování důležitosti
Keywords in different language:	ray tracing;bounding volume hierarchies;Vulkan;illumination;acceleration structures;importance sampling
Abstract in different language:	One of the main performance-heavy areas in raytracing is light sampling. Light sampling is solved in a process called next-event estimation(NEE), where light samples are taken at each ray intersection. Since real-time rendering is an objective, instead of sampling all the luminaries, just a set of lights deemed more important are sampled by using a technique called Monte Carlo Importance Sampling. Aiming further acceleration, some importance sampling based approaches build hierarchical data structures over all light sources, which results in high maintenance costs for dynamic scenes. This paper describes a two-level light bounding volume hierarchy (BVH) of mesh-based lights to accelerate light sampling while minimising the quality loss in dynamic scenes common in similar algorithms. Its main advantage is the ability to have dynamic lights without losing excessive accuracy or performance to maintenance operations. Our approach was developed as an extension to the Mogwai’s PathTracer application from NVIDIA. The algorithm rebuilds the top-level structure in the CPU allowing it to retain its accuracy and refits only the bottom level structures in need of updating on the GPU. The CPU rebuild is a relatively costly operation, to avoid excessive performance loss it is done asynchronously only being used in the next frame. We tested several quality metrics as well as frame times, our implementation achieved an up to 36% increase in MSE and 6% in SSIM with an average of 7% slowdown when compared with the single-level BVH.
Rights:	© Václav Skala - UNION Agency
Appears in Collections:	WSCG 2024: Full Papers Proceedings

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