d2db9927ed
Use sub-pixel differentials for bump mapping helps with reducing artifacts when objects are moving or when textures have high frequency details. Currently we scale it by 0.1 because it seems to work good in practice, we can adjust the value in the future if it turns out to be impractical. Ref: #122892 Pull Request: https://projects.blender.org/blender/blender/pulls/133991
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(BUMP_DX * 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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