Merge branch 'master' into soc-2020-io-performancesoc-2020-io-performance

1 files changed, 105 insertions, 0 deletions

diff --git a/intern/cycles/kernel/osl/shaders/node_principled_hair_bsdf.osl b/intern/cycles/kernel/osl/shaders/node_principled_hair_bsdf.osl
new file mode 100644
index 00000000000..4cf17e0e703
--- /dev/null
+++ b/intern/cycles/kernel/osl/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 "stdcycles.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);
+}