forked from bartvdbraak/blender
b9ce231060
More information in this post: http://code.blender.org/ Thanks to all contributes for giving their permission!
56 lines
1.5 KiB
Plaintext
56 lines
1.5 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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/* "Bump Mapping Unparameterized Surfaces on the GPU"
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* Morten S. Mikkelsen, 2010 */
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surface node_bump(
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int invert = 0,
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normal NormalIn = N,
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float Strength = 0.1,
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float Distance = 1.0,
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float SampleCenter = 0.0,
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float SampleX = 0.0,
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float SampleY = 0.0,
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output normal NormalOut = N)
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{
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/* get surface tangents from normal */
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vector dPdx = Dx(P);
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vector dPdy = Dy(P);
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vector Rx = cross(dPdy, NormalIn);
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vector Ry = cross(NormalIn, dPdx);
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/* compute surface gradient and determinant */
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float det = dot(dPdx, Rx);
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vector surfgrad = (SampleX - SampleCenter) * Rx + (SampleY - SampleCenter) * Ry;
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float absdet = fabs(det);
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float strength = max(Strength, 0.0);
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float dist = Distance;
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if (invert)
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dist *= -1.0;
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/* compute and output perturbed normal */
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NormalOut = normalize(absdet * NormalIn - dist * sign(det) * surfgrad);
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NormalOut = normalize(strength * NormalOut + (1.0 - strength) * NormalIn);
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}
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