Practical Product Importance Sampling for Direct Illumination

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dc.contributor.authorClarberg, Petriken_US
dc.contributor.authorAkenine-Moeller, Tomasen_US
dc.date.accessioned2015-02-21T16:19:49Z
dc.date.available2015-02-21T16:19:49Z
dc.date.issued2008en_US
dc.description.abstractWe present a practical algorithm for sampling the product of environment map lighting and surface reflectance. Our method builds on wavelet-based importance sampling, but has a number of important advantages over previous methods. Most importantly, we avoid using precomputed reflectance functions by sampling the BRDF on-the-fly. Hence, all types of materials can be handled, including anisotropic and spatially varying BRDFs, as well as procedural shaders. This also opens up for using very high resolution, uncompressed, environment maps. Our results show that this gives a significant reduction of variance compared to using lower resolution approximations. In addition, we study the wavelet product, and present a faster algorithm geared for sampling purposes. For our application, the computations are reduced to a simple quadtree-based multiplication. We build the BRDF approximation and evaluate the product in a single tree traversal, which makes the algorithm both faster and more flexible than previous methods.en_US
dc.description.number2en_US
dc.description.seriesinformationComputer Graphics Forumen_US
dc.description.volume27en_US
dc.identifier.doi10.1111/j.1467-8659.2008.01166.xen_US
dc.identifier.issn1467-8659en_US
dc.identifier.pages681-690en_US
dc.identifier.urihttps://doi.org/10.1111/j.1467-8659.2008.01166.xen_US
dc.publisherThe Eurographics Association and Blackwell Publishing Ltden_US
dc.titlePractical Product Importance Sampling for Direct Illuminationen_US
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