47 lines
1.3 KiB
Plaintext
47 lines
1.3 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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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 Normal = N)
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{
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float dx = SampleX - SampleCenter;
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float dy = SampleY - SampleCenter;
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vector dPdx = Dx(P);
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vector dPdy = Dy(P);
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vector Rx = cross(dPdy, N);
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vector Ry = cross(N, dPdx);
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float det = dot(dPdx, Rx);
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vector surfgrad = dx * Rx + dy * Ry;
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surfgrad *= 0.1; /* todo: remove this factor */
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Normal = normalize(abs(det) * N - sign(det) * surfgrad);
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}
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