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/* SPDX-License-Identifier: Apache-2.0
* Copyright 2011-2022 Blender Foundation */
#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
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