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


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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