diff options
Diffstat (limited to 'intern/cycles/kernel/shaders/node_principled_hair_bsdf.osl')
-rw-r--r-- | intern/cycles/kernel/shaders/node_principled_hair_bsdf.osl | 105 |
1 files changed, 105 insertions, 0 deletions
diff --git a/intern/cycles/kernel/shaders/node_principled_hair_bsdf.osl b/intern/cycles/kernel/shaders/node_principled_hair_bsdf.osl new file mode 100644 index 00000000000..757a88f8ece --- /dev/null +++ b/intern/cycles/kernel/shaders/node_principled_hair_bsdf.osl @@ -0,0 +1,105 @@ +/* + * Copyright 2018 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" + +color log3(color a) +{ + return color(log(a[0]), log(a[1]), log(a[2])); +} + +color sigma_from_concentration(float eumelanin, float pheomelanin) +{ + return eumelanin*color(0.506, 0.841, 1.653) + pheomelanin*color(0.343, 0.733, 1.924); +} + +color sigma_from_reflectance(color c, float azimuthal_roughness) +{ + float x = azimuthal_roughness; + float roughness_fac = (((((0.245*x) + 5.574)*x - 10.73)*x + 2.532)*x - 0.215)*x + 5.969; + color sigma = log3(c) / roughness_fac; + return sigma * sigma; +} + +shader node_principled_hair_bsdf( + color Color = color(0.017513, 0.005763, 0.002059), + float Melanin = 0.8, + float MelaninRedness = 1.0, + float RandomColor = 0.0, + color Tint = 1.0, + color AbsorptionCoefficient = color(0.245531, 0.52, 1.365), + normal Normal = Ng, + string parametrization = "Absorption coefficient", + float Offset = radians(2), + float Roughness = 0.3, + float RadialRoughness = 0.3, + float RandomRoughness = 0.0, + float Coat = 0.0, + float IOR = 1.55, + string AttrRandom = "geom:curve_random", + float Random = 0.0, + + output closure color BSDF = 0) +{ + /* Get random value from curve in none is specified. */ + float random_value = 0.0; + + if (isconnected(Random)) { + random_value = Random; + } + else { + getattribute(AttrRandom, random_value); + } + + /* Compute roughness. */ + float factor_random_roughness = 1.0 + 2.0*(random_value - 0.5)*RandomRoughness; + float m0_roughness = 1.0 - clamp(Coat, 0.0, 1.0); + float roughness = Roughness*factor_random_roughness; + float radial_roughness = RadialRoughness*factor_random_roughness; + + /* Compute absorption. */ + color sigma; + + if (parametrization == "Absorption coefficient") { + sigma = AbsorptionCoefficient; + } + else if (parametrization == "Melanin concentration") { + /* Randomize melanin. */ + float factor_random_color = 1.0 + 2.0*(random_value - 0.5) * RandomColor; + float melanin = Melanin * factor_random_color; + + /* Map melanin 0..inf from more perceptually linear 0..1. */ + melanin = -log(max(1.0 - melanin, 0.0001)); + + /* Benedikt Bitterli's melanin ratio remapping. */ + float eumelanin = melanin * (1.0 - MelaninRedness); + float pheomelanin = melanin * MelaninRedness; + color melanin_sigma = sigma_from_concentration(eumelanin, pheomelanin); + + /* Optional tint. */ + color tint_sigma = sigma_from_reflectance(Tint, radial_roughness); + sigma = melanin_sigma + tint_sigma; + } + else if (parametrization == "Direct coloring"){ + sigma = sigma_from_reflectance(Color, radial_roughness); + } + else { + /* Fallback to brownish hair, same as defaults for melanin. */ + sigma = sigma_from_concentration(0.0, 0.8054375); + } + + BSDF = principled_hair(Normal, sigma, roughness, radial_roughness, m0_roughness, Offset, IOR); +} |