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/* SPDX-License-Identifier: Apache-2.0
* Copyright 2011-2022 Blender Foundation */
#include "node_fresnel.h"
#include "stdcycles.h"
shader node_layer_weight(float Blend = 0.5,
normal Normal = N,
output float Fresnel = 0.0,
output float Facing = 0.0)
{
float blend = Blend;
float cosi = dot(I, Normal);
/* Fresnel */
float eta = max(1.0 - Blend, 1e-5);
eta = backfacing() ? eta : 1.0 / eta;
Fresnel = fresnel_dielectric_cos(cosi, eta);
/* Facing */
Facing = fabs(cosi);
if (blend != 0.5) {
blend = clamp(blend, 0.0, 1.0 - 1e-5);
blend = (blend < 0.5) ? 2.0 * blend : 0.5 / (1.0 - blend);
Facing = pow(Facing, blend);
}
Facing = 1.0 - Facing;
}
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