forked from bartvdbraak/blender
58 lines
1.7 KiB
Plaintext
58 lines
1.7 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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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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