Procedural Physically based BRDF for Real-Time Rendering of Glints
Xavier Chermain, Basile Sauvage, Jean-Michel Dischler and Carsten Dachsbacher
Pacific Graphic 2020, CGF issue, DOI: 10.1111/cgf.14141
Abstract
Physically based rendering of glittering surfaces is a challenging problem in computer graphics. Several methods have proposed off-line solutions, but none is dedicated to high-performance graphics. In this work, we propose a novel physically based BRDF for real-time rendering of glints. Our model can reproduce the appearance of sparkling materials (rocks, rough plastics, glitter fabrics, etc.). Compared to the previous real-time method [Zirr and al. 2016], which is not physically based, our BRDF uses normalized NDFs and converges to the standard microfacet BRDF [Cook and Torrance 1982] for a large number of microfacets. Our method procedurally computes NDFs with hundreds of sharp lobes. It relies on a dictionary of 1D marginal distributions: at each location two of them are randomly picked and multiplied (to obtain a NDF), rotated (to increase the variety), and scaled (to control standard deviation/roughness). The dictionary is multiscale, does not depend on roughness, and has a low memory footprint (less than 1 MiB).
Project page: http://igg.unistra.fr/People/chermain/real_time_glint/
Paper (author version): http://igg.unistra.fr/People/chermain/assets/pdf/Chermain2020Procedural.pdf
Paper (official version): https://onlinelibrary.wiley.com/doi/10.1111/cgf.14141
Supplemental video: http://igg.unistra.fr/People/chermain/assets/avi/Chermain2020ProceduralVideo.mp4
Video Two Minute Papers (Thanks to Károly Zsolnai-Fehér): https://www.youtube.com/watch?v=x2zDrSgrlYQ
WebGL (Thanks to Sylvain Thery for the implementation.): http://igg.unistra.fr/People/reproctex/Demos/Real_Time_Glint/
OpenGL: https://github.com/ASTex-ICube/real_time_glint
Shadertoy: https://www.shadertoy.com/view/wstcRH
pbrt-v3: https://github.com/ASTex-ICube/importance_sampling_glint
Slides: http://igg.unistra.fr/People/chermain/assets/pdf/Chermain2020RealTimeWithNotes.pdf
Bibtex: http://igg.unistra.fr/People/chermain/assets/Chermain2020ProceduralBibtex.txt
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