46 lines
1.2 KiB
Plaintext
46 lines
1.2 KiB
Plaintext
/*
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* Copyright 2011-2013 Blender Foundation
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*
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* Licensed under the Apache License, Version 2.0 (the "License");
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* you may not use this file except in compliance with the License.
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* You may obtain a copy of the License at
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS,
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* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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* See the License for the specific language governing permissions and
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* limitations under the License.
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*/
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#include "stdosl.h"
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#include "node_fresnel.h"
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shader node_layer_weight(
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float Blend = 0.5,
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normal Normal = N,
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output float Fresnel = 0.0,
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output float Facing = 0.0)
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{
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float blend = Blend;
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float cosi = dot(I, Normal);
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/* Fresnel */
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float eta = max(1.0 - Blend, 1e-5);
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eta = backfacing() ? eta : 1.0 / eta;
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Fresnel = fresnel_dielectric_cos(cosi, eta);
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/* Facing */
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Facing = fabs(cosi);
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if (blend != 0.5) {
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blend = clamp(blend, 0.0, 1.0 - 1e-5);
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blend = (blend < 0.5) ? 2.0 * blend : 0.5 / (1.0 - blend);
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Facing = pow(Facing, blend);
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}
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Facing = 1.0 - Facing;
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}
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