55 lines
1.5 KiB
Plaintext
55 lines
1.5 KiB
Plaintext
/* SPDX-FileCopyrightText: 2011-2022 Blender Foundation
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*
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* SPDX-License-Identifier: Apache-2.0 */
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#include "stdcycles.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(int invert = 0,
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int use_object_space = 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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point Ptmp = P;
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normal Normal = NormalIn;
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if (use_object_space) {
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Ptmp = transform("object", Ptmp);
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Normal = normalize(transform("object", Normal));
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}
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/* get surface tangents from normal */
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vector dPdx = Dx(Ptmp);
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vector dPdy = Dy(Ptmp);
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vector Rx = cross(dPdy, Normal);
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vector Ry = cross(Normal, 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 * Normal - dist * sign(det) * surfgrad);
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NormalOut = normalize(strength * NormalOut + (1.0 - strength) * Normal);
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if (use_object_space) {
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NormalOut = normalize(transform("object", "world", NormalOut));
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}
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}
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