0315eae536
Previously, Cycles only supported the Henyey-Greenstein phase function for volume scattering. While HG is flexible and works for a wide range of effects, sometimes a more physically accurate phase function may be needed for realism. Therefore, this adds three new phase functions to the code: Rayleigh: For particles with a size below the wavelength of light, mostly athmospheric scattering. Fournier-Forand: For realistic underwater scattering. Draine: Fairly specific on its own (mostly for interstellar dust), but useful for the next entry. Mie: Approximates Mie scattering in water droplets using a mix of Draine and HG phase functions. These phase functions can be combined using Mix nodes as usual. Co-authored-by: Lukas Stockner <lukas@lukasstockner.de> Pull Request: https://projects.blender.org/blender/blender/pulls/123532
73 lines
2.8 KiB
C
73 lines
2.8 KiB
C
/* SPDX-FileCopyrightText: 2009-2010 Sony Pictures Imageworks Inc., et al. All Rights Reserved.
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* SPDX-FileCopyrightText: 2011-2022 Blender Foundation
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*
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* SPDX-License-Identifier: BSD-3-Clause
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*
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* Adapted code from Open Shading Language. */
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#ifndef CCL_STDCYCLESOSL_H
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#define CCL_STDCYCLESOSL_H
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#include "stdosl.h"
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// Constants
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#define FLT_MAX 3.402823466e+38 // max value
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// Declaration of built-in functions and closures, stdosl.h does not make
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// these available so we have to redefine them.
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#define BUILTIN [[int builtin = 1]]
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#define BUILTIN_DERIV [[ int builtin = 1, int deriv = 1 ]]
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closure color diffuse_ramp(normal N, color colors[8]) BUILTIN;
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closure color phong_ramp(normal N, float exponent, color colors[8]) BUILTIN;
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closure color diffuse_toon(normal N, float size, float smooth) BUILTIN;
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closure color glossy_toon(normal N, float size, float smooth) BUILTIN;
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closure color ashikhmin_velvet(normal N, float sigma) BUILTIN;
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closure color sheen(normal N, float roughness) BUILTIN;
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closure color ambient_occlusion() BUILTIN;
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closure color microfacet_f82_tint(
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string distribution, vector N, vector T, float ax, float ay, color f0, color f82) BUILTIN;
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/* Needed to pass along the color for multi-scattering saturation adjustment,
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* otherwise could be replaced by microfacet() */
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closure color microfacet_multi_ggx_glass(normal N, float ag, float eta, color C) BUILTIN;
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closure color microfacet_multi_ggx_aniso(normal N, vector T, float ax, float ay, color C) BUILTIN;
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// BSSRDF
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closure color bssrdf(string method, normal N, vector radius, color albedo) BUILTIN;
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// Hair
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closure color
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hair_reflection(normal N, float roughnessu, float roughnessv, vector T, float offset) BUILTIN;
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closure color
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hair_transmission(normal N, float roughnessu, float roughnessv, vector T, float offset) BUILTIN;
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closure color hair_chiang(normal N,
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color sigma,
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float roughnessu,
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float roughnessv,
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float coat,
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float alpha,
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float eta) BUILTIN;
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closure color hair_huang(normal N,
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color sigma,
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float roughness,
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float tilt,
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float eta,
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float aspect_ratio,
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float r_lobe,
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float tt_lobe,
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float trt_lobe) BUILTIN;
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// Volume
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closure color henyey_greenstein(float g) BUILTIN;
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closure color fournier_forand(float B, float IOR) BUILTIN;
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closure color draine(float g, float alpha) BUILTIN;
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closure color rayleigh() BUILTIN;
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closure color absorption() BUILTIN;
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// Ray Portal
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closure color ray_portal_bsdf(vector position, vector direction) BUILTIN;
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#endif /* CCL_STDOSL_H */
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