Add Chromium-only Blender WebEngine parity work

blender-5.2.0/intern/cycles/kernel/svm/fresnel.h

@@ -0,0 +1,65 @@
+/* SPDX-FileCopyrightText: 2011-2022 Blender Foundation
+ *
+ * SPDX-License-Identifier: Apache-2.0 */
+
+#pragma once
+
+#include "kernel/closure/bsdf_util.h"
+
+#include "kernel/svm/node_types.h"
+#include "kernel/svm/util.h"
+
+CCL_NAMESPACE_BEGIN
+
+/* Fresnel Node */
+
+ccl_device_noinline void svm_node_fresnel(ccl_private ShaderData *sd,
+                                          ccl_private float *ccl_restrict stack,
+                                          const ccl_global SVMNodeFresnel &ccl_restrict node)
+{
+  float eta = stack_load(stack, node.ior);
+  const float3 normal_in = stack_load_float3_default(stack, node.normal_offset, sd->N);
+
+  eta = fmaxf(eta, 1e-5f);
+  eta = (sd->flag & SD_BACKFACING) ? 1.0f / eta : eta;
+
+  const float f = fresnel_dielectric_cos(dot(sd->wi, normal_in), eta);
+
+  stack_store_float(stack, node.out_offset, f);
+}
+
+/* Layer Weight Node */
+
+ccl_device_noinline void svm_node_layer_weight(ccl_private ShaderData *sd,
+                                               ccl_private float *ccl_restrict stack,
+                                               const ccl_global SVMNodeLayerWeight &ccl_restrict
+                                                   node)
+{
+  float blend = stack_load(stack, node.blend);
+  const float3 normal_in = stack_load_float3_default(stack, node.normal_offset, sd->N);
+
+  float f;
+
+  if (node.weight_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->wi, normal_in), eta);
+  }
+  else {
+    f = fabsf(dot(sd->wi, 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, node.out_offset, f);
+}
+
+CCL_NAMESPACE_END