Brecht Van Lommel
b12151eceb
* Anisotropic BSDF now supports GGX and Beckmann distributions, Ward has been removed because other distributions are superior. * GGX is now the default distribution for all glossy and anisotropic nodes, since it looks good, has low noise and is fast to evaluate. * Ashikhmin-Shirley is now available in the Glossy BSDF.
58 lines
1.6 KiB
Plaintext
58 lines
1.6 KiB
Plaintext
/*
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* Copyright 2011-2013 Blender Foundation
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*
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* Licensed under the Apache License, Version 2.0 (the "License");
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* you may not use this file except in compliance with the License.
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* You may obtain a copy of the License at
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS,
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* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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* See the License for the specific language governing permissions and
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* limitations under the License
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*/
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#include "stdosl.h"
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shader node_anisotropic_bsdf(
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color Color = 0.0,
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string distribution = "GGX",
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float Roughness = 0.0,
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float Anisotropy = 0.0,
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float Rotation = 0.0,
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normal Normal = N,
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normal Tangent = normalize(dPdu),
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output closure color BSDF = 0)
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{
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/* rotate tangent around normal */
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vector T = Tangent;
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if (Rotation != 0.0)
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T = rotate(T, Rotation * M_2PI, point(0.0, 0.0, 0.0), Normal);
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/* compute roughness */
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float RoughnessU, RoughnessV;
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float aniso = clamp(Anisotropy, -0.99, 0.99);
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if (aniso < 0.0) {
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RoughnessU = Roughness / (1.0 + aniso);
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RoughnessV = Roughness * (1.0 + aniso);
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}
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else {
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RoughnessU = Roughness * (1.0 - aniso);
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RoughnessV = Roughness / (1.0 - aniso);
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}
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if (distribution == "Sharp")
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BSDF = Color * reflection(Normal);
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else if (distribution == "Beckmann")
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BSDF = Color * microfacet_beckmann_aniso(Normal, T, RoughnessU, RoughnessV);
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else if (distribution == "GGX")
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BSDF = Color * microfacet_ggx_aniso(Normal, T, RoughnessU, RoughnessV);
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else
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BSDF = Color * ashikhmin_shirley(Normal, T, RoughnessU, RoughnessV);
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}
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