1 files changed, 84 insertions, 0 deletions
diff --git a/intern/cycles/kernel/svm/fresnel.h b/intern/cycles/kernel/svm/fresnel.h
new file mode 100644
index 00000000000..9dd68c3e38f
--- /dev/null
+++ b/intern/cycles/kernel/svm/fresnel.h
@@ -0,0 +1,84 @@
+/*
+ * 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.
+ */
+
+#pragma once
+
+CCL_NAMESPACE_BEGIN
+
+/* Fresnel Node */
+
+ccl_device_noinline void svm_node_fresnel(ccl_private ShaderData *sd,
+                                          ccl_private float *stack,
+                                          uint ior_offset,
+                                          uint ior_value,
+                                          uint node)
+{
+  uint normal_offset, out_offset;
+  svm_unpack_node_uchar2(node, &normal_offset, &out_offset);
+  float eta = (stack_valid(ior_offset)) ? stack_load_float(stack, ior_offset) :
+                                          __uint_as_float(ior_value);
+  float3 normal_in = stack_valid(normal_offset) ? stack_load_float3(stack, normal_offset) : sd->N;
+
+  eta = fmaxf(eta, 1e-5f);
+  eta = (sd->flag & SD_BACKFACING) ? 1.0f / eta : eta;
+
+  float f = fresnel_dielectric_cos(dot(sd->I, normal_in), eta);
+
+  stack_store_float(stack, out_offset, f);
+}
+
+/* Layer Weight Node */
+
+ccl_device_noinline void svm_node_layer_weight(ccl_private ShaderData *sd,
+                                               ccl_private float *stack,
+                                               uint4 node)
+{
+  uint blend_offset = node.y;
+  uint blend_value = node.z;
+
+  uint type, normal_offset, out_offset;
+  svm_unpack_node_uchar3(node.w, &type, &normal_offset, &out_offset);
+
+  float blend = (stack_valid(blend_offset)) ? stack_load_float(stack, blend_offset) :
+                                              __uint_as_float(blend_value);
+  float3 normal_in = (stack_valid(normal_offset)) ? stack_load_float3(stack, normal_offset) :
+                                                    sd->N;
+
+  float f;
+
+  if (type == NODE_LAYER_WEIGHT_FRESNEL) {
+    float eta = fmaxf(1.0f - blend, 1e-5f);
+    eta = (sd->flag & SD_BACKFACING) ? eta : 1.0f / eta;
+
+    f = fresnel_dielectric_cos(dot(sd->I, normal_in), eta);
+  }
+  else {
+    f = fabsf(dot(sd->I, normal_in));
+
+    if (blend != 0.5f) {
+      blend = clamp(blend, 0.0f, 1.0f - 1e-5f);
+      blend = (blend < 0.5f) ? 2.0f * blend : 0.5f / (1.0f - blend);
+
+      f = powf(f, blend);
+    }
+
+    f = 1.0f - f;
+  }
+
+  stack_store_float(stack, out_offset, f);
+}
+
+CCL_NAMESPACE_END