Deprecated: The each() function is deprecated. This message will be suppressed on further calls in /home/zhenxiangba/zhenxiangba.com/public_html/phproxy-improved-master/index.php on line 456 All-Frequency Relighting of Non-Diffuse Objects using Separable BRDF Approximation
Proceedings of 15th Eurographics
Symposium on Rendering (EGSR 2004)
Abstract:
This paper presents a technique, based on pre-computed light
transport and separable BRDF approximation, for interactive rendering of
non-diffuse objects under all-frequency environment illumination. Existing
techniques using spherical harmonics to represent environment maps and transport
functions are limited to low-frequency light transport effects. Non-linear
wavelet lighting approximation is able to capture all-frequency illumination and
shadows for geometry relighting, but interactive rendering is currently limited
to diffuse objects. Our work extends the wavelet-based approach to relighting of
non-diffuse objects. We factorize the BRDF using separable decomposition and
keep only a few low-order approximation terms, each consisting of a 2D light map
paired with a 2D view map. We then pre-compute light transport matrices
corresponding to each BRDF light map, and compress the data with a non-linear
wavelet approximation. We use modern graphics hardware to accelerate
precomputation. At run-time, a sparse light vector is multiplied by the sparse
transport matrix at each vertex, and the results are further combined with
texture lookups of the view direction into the BRDF view maps to produce
view-dependent color. Using our technique, we demonstrate rendering of objects
with several non-diffuse BRDFs under all-frequency, dynamic environment lighting
at interactive rates.