1 files changed, 62 insertions, 0 deletions
diff --git a/intern/cycles/kernel/osl/shaders/node_fresnel.h b/intern/cycles/kernel/osl/shaders/node_fresnel.h
new file mode 100644
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+++ b/intern/cycles/kernel/osl/shaders/node_fresnel.h
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+/*
+ * Adapted from Open Shading Language with this license:
+ *
+ * Copyright (c) 2009-2010 Sony Pictures Imageworks Inc., et al.
+ * All Rights Reserved.
+ *
+ * Modifications Copyright 2011, Blender Foundation.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are
+ * met:
+ * * Redistributions of source code must retain the above copyright
+ *   notice, this list of conditions and the following disclaimer.
+ * * Redistributions in binary form must reproduce the above copyright
+ *   notice, this list of conditions and the following disclaimer in the
+ *   documentation and/or other materials provided with the distribution.
+ * * Neither the name of Sony Pictures Imageworks nor the names of its
+ *   contributors may be used to endorse or promote products derived from
+ *   this software without specific prior written permission.
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+ * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+ * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+ * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+ * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+ * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+ * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+ * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+ * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+ * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ */
+
+float fresnel_dielectric_cos(float cosi, float eta)
+{
+  /* compute fresnel reflectance without explicitly computing
+   * the refracted direction */
+  float c = fabs(cosi);
+  float g = eta * eta - 1 + c * c;
+  float result;
+
+  if (g > 0) {
+    g = sqrt(g);
+    float A = (g - c) / (g + c);
+    float B = (c * (g + c) - 1) / (c * (g - c) + 1);
+    result = 0.5 * A * A * (1 + B * B);
+  }
+  else
+    result = 1.0; /* TIR (no refracted component) */
+
+  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;
+}