Browsing by Author "Ogaki, Shinji"

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    Generalized Light Portals
    (ACM, 2020) Ogaki, Shinji; Yuksel, Cem and Membarth, Richard and Zordan, Victor
    Light portals are useful for accelerating the convergence of Monte Carlo path tracing when rendering interiors. However, they are generally limited to flat polygonal shapes. In this paper, we introduce a new concept that allows existing polygon meshes with arbitrary shaders in a scene to be used as generalized light portals. We also present an efficient sampling method that takes into account the pixel values of the environment map and ray guiding two-dimensional textures that are typically opacity or transparency maps. This novel sampling strategy can be combined with other sampling techniques by using multiple importance sampling.
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    A Survey on Bounding Volume Hierarchies for Ray Tracing
    (The Eurographics Association and John Wiley & Sons Ltd., 2021) Meister, Daniel; Ogaki, Shinji; Benthin, Carsten; Doyle, Michael J.; Guthe, Michael; Bittner, Jirí; Bühler, Katja and Rushmeier, Holly
    Ray tracing is an inherent part of photorealistic image synthesis algorithms. The problem of ray tracing is to find the nearest intersection with a given ray and scene. Although this geometric operation is relatively simple, in practice, we have to evaluate billions of such operations as the scene consists of millions of primitives, and the image synthesis algorithms require a high number of samples to provide a plausible result. Thus, scene primitives are commonly arranged in spatial data structures to accelerate the search. In the last two decades, the bounding volume hierarchy (BVH) has become the de facto standard acceleration data structure for ray tracing-based rendering algorithms in offline and recently also in real-time applications. In this report, we review the basic principles of bounding volume hierarchies as well as advanced state of the art methods with a focus on the construction and traversal. Furthermore, we discuss industrial frameworks, specialized hardware architectures, other applications of bounding volume hierarchies, best practices, and related open problems.