forked from bartvdbraak/blender
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
/*
|
|
* Copyright 2011-2013 Blender Foundation
|
|
*
|
|
* Licensed under the Apache License, Version 2.0 (the "License");
|
|
* you may not use this file except in compliance with the License.
|
|
* You may obtain a copy of the License at
|
|
*
|
|
* http://www.apache.org/licenses/LICENSE-2.0
|
|
*
|
|
* Unless required by applicable law or agreed to in writing, software
|
|
* distributed under the License is distributed on an "AS IS" BASIS,
|
|
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
|
|
* See the License for the specific language governing permissions and
|
|
* limitations under the License
|
|
*/
|
|
|
|
#include "stdosl.h"
|
|
|
|
shader node_anisotropic_bsdf(
|
|
color Color = 0.0,
|
|
string distribution = "GGX",
|
|
float Roughness = 0.0,
|
|
float Anisotropy = 0.0,
|
|
float Rotation = 0.0,
|
|
normal Normal = N,
|
|
normal Tangent = normalize(dPdu),
|
|
output closure color BSDF = 0)
|
|
{
|
|
/* rotate tangent around normal */
|
|
vector T = Tangent;
|
|
|
|
if (Rotation != 0.0)
|
|
T = rotate(T, Rotation * M_2PI, point(0.0, 0.0, 0.0), Normal);
|
|
|
|
/* compute roughness */
|
|
float RoughnessU, RoughnessV;
|
|
float aniso = clamp(Anisotropy, -0.99, 0.99);
|
|
|
|
if (aniso < 0.0) {
|
|
RoughnessU = Roughness / (1.0 + aniso);
|
|
RoughnessV = Roughness * (1.0 + aniso);
|
|
}
|
|
else {
|
|
RoughnessU = Roughness * (1.0 - aniso);
|
|
RoughnessV = Roughness / (1.0 - aniso);
|
|
}
|
|
|
|
if (distribution == "Sharp")
|
|
BSDF = Color * reflection(Normal);
|
|
else if (distribution == "Beckmann")
|
|
BSDF = Color * microfacet_beckmann_aniso(Normal, T, RoughnessU, RoughnessV);
|
|
else if (distribution == "GGX")
|
|
BSDF = Color * microfacet_ggx_aniso(Normal, T, RoughnessU, RoughnessV);
|
|
else
|
|
BSDF = Color * ashikhmin_shirley(Normal, T, RoughnessU, RoughnessV);
|
|
}
|
|
|