Position-Normal Manifold for Efficient Glint Rendering on High-Resolution Normal Maps

Fuente: arXiv
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Autores principales: Wu, Liwen, Luan, Fujun, Hašan, Miloš, Ramamoorthi, Ravi
Formato: Preprint
Publicado: 2025
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author Wu, Liwen
Luan, Fujun
Hašan, Miloš
Ramamoorthi, Ravi
author_facet Wu, Liwen
Luan, Fujun
Hašan, Miloš
Ramamoorthi, Ravi
contents Detailed microstructures on specular objects often exhibit intriguing glinty patterns under high-frequency lighting, which is challenging to render using a conventional normal-mapped BRDF. In this paper, we present a manifold-based formulation of the glint normal distribution functions (NDF) that precisely captures the surface normal distributions over queried footprints. The manifold-based formulation transfers the integration for the glint NDF construction to a problem of mesh intersections. Compared to previous works that rely on complex numerical approximations, our integral solution is exact and much simpler to compute, which also allows an easy adaptation of a mesh clustering hierarchy to accelerate the NDF evaluation of large footprints. Our performance and quality analysis shows that our NDF formulation achieves similar glinty appearance compared to the baselines but is an order of magnitude faster. Within this framework, we further present a novel derivation of analytical shadow-masking for normal-mapped diffuse surfaces -- a component that is often ignored in previous works.
format Preprint
id arxiv_https___arxiv_org_abs_2505_08985
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Position-Normal Manifold for Efficient Glint Rendering on High-Resolution Normal Maps
Wu, Liwen
Luan, Fujun
Hašan, Miloš
Ramamoorthi, Ravi
Graphics
Detailed microstructures on specular objects often exhibit intriguing glinty patterns under high-frequency lighting, which is challenging to render using a conventional normal-mapped BRDF. In this paper, we present a manifold-based formulation of the glint normal distribution functions (NDF) that precisely captures the surface normal distributions over queried footprints. The manifold-based formulation transfers the integration for the glint NDF construction to a problem of mesh intersections. Compared to previous works that rely on complex numerical approximations, our integral solution is exact and much simpler to compute, which also allows an easy adaptation of a mesh clustering hierarchy to accelerate the NDF evaluation of large footprints. Our performance and quality analysis shows that our NDF formulation achieves similar glinty appearance compared to the baselines but is an order of magnitude faster. Within this framework, we further present a novel derivation of analytical shadow-masking for normal-mapped diffuse surfaces -- a component that is often ignored in previous works.
title Position-Normal Manifold for Efficient Glint Rendering on High-Resolution Normal Maps
topic Graphics
url https://arxiv.org/abs/2505.08985