Precomputed Radiance Transfer for Dynamic Scenes Taking into Account Light Interreflection
Proceedings of the 18th Eurographics conference on Rendering Techniques (EGSR 2007) pp. 35-44
Kei Iwasaki1, Yoshinori Dobashi2, Fujiichi Yoshimoto1, Tomoyuki Nishita3
1Wakayama University, 2Hokkaido University, 3The University of Tokyo
Abstract
Fast rendering of dynamic scenes taking into account global illumination is one of
the most challenging tasks in computer graphics. This paper proposes a new precomputed
radiance transfer (PRT) method for rendering dynamic scenes of rigid objects taking
into account interreflections of light between surfaces with diffuse and glossy BRDFs.
To compute the interreflections of light between rigid objects, we consider the objects
as secondary light sources. We represent the intensity distributions on the surface of
the objects with a linear combination of basis functions. We then calculate a component
of the irradiance per basis function at each vertex of the object when illuminated by
the secondary light source. We call this component of the irradiance, the basis irradiance.
The irradiance is represented with a linear combination of the basis irradiances, which
are computed efficiently at run-time by using a PRT technique. By using the basis
irradiance, the calculation of multiple-bounce interreflected light is simplified and
can be evaluated very quickly. We demonstrate the real-time rendering of dynamic scenes
for low-frequency lighting and rendering for all-frequency lighting at interactive frame
rates.
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