Cycles / OSL: Add a conductive fresnel shader template.

This adds a fresnel conductive OSL preset to the Text Editor. Based on a patch by Lukas Stockner.
Differential revision: https://developer.blender.org/D145

See the differential for details.

3 files changed, 60 insertions, 7 deletions

diff --git a/intern/cycles/kernel/closure/bsdf_util.h b/intern/cycles/kernel/closure/bsdf_util.h
index b3dcb9dcc38..6851dca309b 100644
--- a/intern/cycles/kernel/closure/bsdf_util.h
+++ b/intern/cycles/kernel/closure/bsdf_util.h
@@ -111,14 +111,16 @@ ccl_device float fresnel_dielectric_cos(float cosi, float eta)
 	return 1.0f; // TIR(no refracted component)
 }
 
-ccl_device float fresnel_conductor(float cosi, float eta, float k)
+ccl_device float3 fresnel_conductor(float cosi, const float3 eta, const float3 k)
 {
-	float tmp_f = eta * eta + k * k;
-	float tmp = tmp_f * cosi * cosi;
-	float Rparl2 = (tmp - (2.0f * eta * cosi) + 1)/
-	               (tmp + (2.0f * eta * cosi) + 1);
-	float Rperp2 = (tmp_f - (2.0f * eta * cosi) + cosi * cosi)/
-	               (tmp_f + (2.0f * eta * cosi) + cosi * cosi);
+	float3 cosi2 = make_float3(cosi*cosi);
+	float3 one = make_float3(1.0f, 1.0f, 1.0f);
+	float3 tmp_f = eta * eta + k * k;
+	float3 tmp = tmp_f * cosi2;
+	float3 Rparl2 = (tmp - (2.0f * eta * cosi) + one) /
+					(tmp + (2.0f * eta * cosi) + one);
+	float3 Rperp2 = (tmp_f - (2.0f * eta * cosi) + cosi2) /
+					(tmp_f + (2.0f * eta * cosi) + cosi2);
 	return(Rparl2 + Rperp2) * 0.5f;
 }
 
diff --git a/intern/cycles/kernel/shaders/node_fresnel.h b/intern/cycles/kernel/shaders/node_fresnel.h
index 447a84255ef..9f10ba8023e 100644
--- a/intern/cycles/kernel/shaders/node_fresnel.h
+++ b/intern/cycles/kernel/shaders/node_fresnel.h
@@ -34,3 +34,16 @@ float fresnel_dielectric_cos(float cosi, float eta)
 	return result;
 }
 
+color fresnel_conductor(float cosi, color eta, color k)
+{
+	color cosi2 = color(cosi*cosi);
+	color one = color(1, 1, 1);
+	color tmp_f = eta * eta + k * k;
+	color tmp = tmp_f * cosi2;
+	color Rparl2 = (tmp - (2.0 * eta * cosi) + one) /
+					(tmp + (2.0 * eta * cosi) + one);
+	color Rperp2 = (tmp_f - (2.0 * eta * cosi) + cosi2) /
+					(tmp_f + (2.0 * eta * cosi) + cosi2);
+	return (Rparl2 + Rperp2) * 0.5;
+}
+
diff --git a/release/scripts/templates_osl/fresnel_conductive.osl b/release/scripts/templates_osl/fresnel_conductive.osl
new file mode 100644
index 00000000000..c197656eaee
--- /dev/null
+++ b/release/scripts/templates_osl/fresnel_conductive.osl
@@ -0,0 +1,38 @@
+/*
+ * Copyright 2011-2014 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
+ */
+
+color fresnel_conductor(float cosi, color eta, color k)
+{
+	color cosi2 = color(cosi*cosi);
+	color one = color(1, 1, 1);
+	color tmp_f = eta * eta + k * k;
+	color tmp = tmp_f * cosi2;
+	color Rparl2 = (tmp - (2.0 * eta * cosi) + one) /
+					(tmp + (2.0 * eta * cosi) + one);
+	color Rperp2 = (tmp_f - (2.0 * eta * cosi) + cosi2) /
+					(tmp_f + (2.0 * eta * cosi) + cosi2);
+	return (Rparl2 + Rperp2) * 0.5;
+}
+
+shader node_fresnel_conductive(
+	color n = color(0.084136, 0.410708, 1.472421),
+	color k = color(4.018579, 2.363371, 1.607574),
+	normal Normal = N,
+	output color Color = color(0.8, 0.8, 0.8))
+{
+	float cosi = dot(I, Normal);
+	Color = fresnel_conductor(cosi, n, k);
+}