The Bounced Z-buffer for Indirect Visibility

Nalbach, Oliver; Ritschel, Tobias; Seidel, Hans-Peter

The Bounced Z-buffer for Indirect Visibility

Files

079-086.pdf (43 MB)

zBuffer.avi (77.94 MB)

Date

2015

Authors

Nalbach, Oliver
Ritschel, Tobias
Seidel, Hans-Peter

Publisher

The Eurographics Association

Abstract

Synthesizing images of animated scenes with indirect illumination and glossy materials at interactive frame rates commonly ignores indirect shadows. In this work we extend a class of indirect lighting algorithms that splat shading to a framebuffer - we demonstrate deep screen space and ambient occlusion volumes - to include indirect visibility. To this end we propose the bounced z-buffer: While a common z-buffered framebuffer, at each pixel, maintains the distance from the closest surface and its radiance along a direction from the camera to that pixel, our new representation contains the distance from the closest surface and its radiance after one indirect bounce into a certain other direction. Consequently, with bounced z-buffering, only the splat from the nearest emitter in one direction contributes to each pixel. Importance-sampling the bounced directions according to the product of cosine term and BRDF allows to approximate full shading by a simple sum of neighboring framebuffer pixels.

        @inproceedings{10.2312:vmv.20151261
,
booktitle = {Vision, Modeling & Visualization
},
editor = {David Bommes and Tobias Ritschel and Thomas Schultz
},
title = {{The Bounced Z-buffer for Indirect Visibility
}},
author = {Nalbach, Oliver and 
Ritschel, Tobias and 
Seidel, Hans-Peter
},
year = {2015
},
publisher = {The Eurographics Association
},
ISBN = {978-3-905674-95-8
},
DOI = {10.2312/vmv.20151261
}
}