Real-Time Pixel-Perfect Hard Shadows with Leak Tracing
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Date
2024
Authors
Journal Title
Journal ISSN
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Publisher
The Eurographics Association
Abstract
Accurate shadows greatly enhance the realism of a rendered image. Shadow mapping is the preferred solution for shadows in real-time applications. However, shadow maps suffer from discretization errors and self-shadowing artifacts, that need custom parameter tuning per scene. Filterable shadow maps such as variance or moment shadow maps solve both issues but introduce light leaking. With the advent of hardware ray tracing, it becomes more realistic to use shadow rays instead of a shadow map. However, distributing a shadow ray is often more expensive than evaluating a shadow map, especially if the ray hits alphatested geometry. We introduce leak tracing, where we use filterable shadow maps techniques on top of default shadow maps and eliminate the light leaks and aliased shadow edges with selective ray tracing. Our algorithm does not need any scene-dependent parameters. We achieve an average speedup ranging from 1.19 to 1.79, with a top speedup of 4.17, depending on the scene and eliminate major performance drops caused by alpha-tested geometry during ray tracing. Our solution is temporally stable and reaches similar quality as pure ray tracing.
Description
CCS Concepts: Computing methodologies -> Ray tracing; Rasterization; Visibility
@inproceedings{10.2312:sr.20241158,
booktitle = {Eurographics Symposium on Rendering},
editor = {Haines, Eric and Garces, Elena},
title = {{Real-Time Pixel-Perfect Hard Shadows with Leak Tracing}},
author = {Kern, René and Brüll, Felix and Grosch, Thorsten},
year = {2024},
publisher = {The Eurographics Association},
ISSN = {1727-3463},
ISBN = {978-3-03868-262-2},
DOI = {10.2312/sr.20241158}
}