forked from bartvdbraak/blender
d236b4d60f
give results that were either too weak or too strong, this makes it give more predictable results. The downside is that it breaks backwards compatibility but the previous behavior was almost broken.
52 lines
1.6 KiB
Plaintext
52 lines
1.6 KiB
Plaintext
/*
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* Copyright 2011, Blender Foundation.
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*
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* This program is free software; you can redistribute it and/or
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* modify it under the terms of the GNU General Public License
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* as published by the Free Software Foundation; either version 2
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* of the License, or (at your option) any later version.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program; if not, write to the Free Software Foundation,
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* Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
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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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normal NormalIn = N,
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float Strength = 0.0,
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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 = clamp(Strength, 0.0, 1.0);
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/* compute and output perturbed normal */
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NormalOut = normalize(absdet * NormalIn - sign(det) * surfgrad);
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NormalOut = normalize(strength*NormalOut + (1.0 - strength)*NormalIn);
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}
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