Deep Partitioned Shadow Volumes Using Stackless and Hybrid Traversals

Mora, Frédéric; Gerhards, Julien; Aveneau, Lilian; Ghazanfarpour, Djamchid

Deep Partitioned Shadow Volumes Using Stackless and Hybrid Traversals

Files

073-083.pdf (6.2 MB)

Date

2016

Authors

Mora, Frédéric
Gerhards, Julien
Aveneau, Lilian
Ghazanfarpour, Djamchid

Publisher

The Eurographics Association

Abstract

Computing accurate hard shadows is a difficult problem in interactive rendering. Previous methods rely either on Shadow Maps or Shadow Volumes. Recently Partitioned Shadow Volumes (PSV) has been introduced. It revisits the old Shadow Volumes Binary Tree Space Partitioning algorithm, leading to a practicable and efficient technique. In this article, we analyze the PSV query algorithm and identify two main drawbacks: First, it uses a stack which is not GPU friendly; its size must be small enough to reduce the register pressure, but large enough to avoid stack overflow. Second, PSV struggles with configurations involving significant depth complexity, especially for lit points. We solve these problems by adding a depth information to the PSV data structure, and by designing a stackless query. In addition, we show how to combine the former PSV query with our stackless solution, leading to a hybrid technique taking advantage of both. This eliminates any risk of stack overflow, and our experiments demonstrate that these improvements accelerate the rendering time up to a factor of 3.

        @inproceedings{10.2312:sre.20161212
,
booktitle = {Eurographics Symposium on Rendering - Experimental Ideas & Implementations
},
editor = {Elmar Eisemann and Eugene Fiume
},
title = {{Deep Partitioned Shadow Volumes Using Stackless and Hybrid Traversals
}},
author = {Mora, Frédéric and 
Gerhards, Julien and 
Aveneau, Lilian and 
Ghazanfarpour, Djamchid
},
year = {2016
},
publisher = {The Eurographics Association
},
ISSN = {1727-3463
},
ISBN = {978-3-03868-019-2
},
DOI = {10.2312/sre.20161212
}
}