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/*
* Copyright 2011, Blender Foundation.
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License
* as published by the Free Software Foundation; either version 2
* of the License, or (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software Foundation,
* Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
*/
#include "stdosl.h"
#include "node_fresnel.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;
/* Fresnel */
float eta = max(1.0 - Blend, 1e-5);
eta = backfacing() ? eta : 1.0 / eta;
Fresnel = fresnel_dielectric(I, Normal, eta);
/* Facing */
Facing = abs(dot(I, Normal));
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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