Browsing by Author "Mallett, Ian"

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    Aesthetically-Oriented Atmospheric Scattering
    (The Eurographics Association, 2019) Shen, Yang; Mallett, Ian; Shkurko, Konstantin; Kaplan, Craig S. and Forbes, Angus and DiVerdi, Stephen
    We present Aesthetically-Oriented Atmospheric Scattering (AOAS): an experiment into the feasibility of using real-time rendering as a tool to explore sky styles. AOAS provides an interactive design environment which enables rapid iteration cycles from concept to implementation to preview. Existing real-time rendering techniques for atmospheric scattering struggle to produce non-photorealistic sky styles within any 3D scene. To solve this problem, first, we simplify the geometric representation of atmospheric scattering to a single skydome to leverage the flexibility and simplicity of skydomes in compositing with 3D scenes. Second, we classify the essential and non-essential visual characteristics of the sky and allow AOAS to vary the latter, thus producing meaningful, non-photorealistic sky styles with real-time atmospheric scattering that are still recognizable as skies, but contain artistic stylization. We use AOAS to generate a wide variety of sky examples ranging from physical to highly stylized in appearance. The algorithm can be easily implemented on the GPU, and performs at interactive frame rates with low memory consumption and CPU usage.
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    Patch Textures: Hardware Implementation of Mesh Colors
    (The Eurographics Association, 2019) Mallett, Ian; Seiler, Larry; Yuksel, Cem; Steinberger, Markus and Foley, Tim
    Mesh colors provide an effective alternative to standard texture mapping. They significantly simplify the asset production pipeline by removing the need for defining a mapping and eliminate rendering artifacts due to seams. This paper addresses the problem that using mesh colors for real-time rendering has not been practical, due to the absence of hardware support. We show that it is possible to provide full hardware texture filtering support for mesh colors with minimal changes to existing GPUs by introducing a hardware-friendly representation for mesh colors that we call patch textures. We discuss the hardware modifications needed for storing and filtering patch textures.
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    Spectral Primary Decomposition for Rendering with sRGB Reflectance
    (The Eurographics Association, 2019) Mallett, Ian; Yuksel, Cem; Boubekeur, Tamy and Sen, Pradeep
    Spectral renderers, as-compared to RGB renderers, are able to simulate light transport that is closer to reality, capturing light behavior that is impossible to simulate with any three-primary decomposition. However, spectral rendering requires spectral scene data (e.g. textures and material properties), which is not widely available, severely limiting the practicality of spectral rendering. Unfortunately, producing a physically valid reflectance spectrum from a given sRGB triple has been a challenging problem, and indeed until very recently constructing a spectrum without colorimetric round-trip error was thought to be impossible. In this paper, we introduce a new procedure for efficiently generating a reflectance spectrum from any given sRGB input data. We show for the first time that it is possible to create any sRGB reflectance spectrum as a linear combination of three separate spectra, each directly corresponding to one of the BT.709 primaries. Our approach produces consistent results, such that the input sRGB value is perfectly reproduced by the corresponding reflectance spectrum under D65 illumination, bounded only by Monte Carlo and numerical error. We provide a complete implementation, including a precomputed spectral basis, and discuss important optimizations and generalization to other RGB spaces.