0df9b2c715
It is basically brute force volume scattering within the mesh, but part of the SSS code for faster performance. The main difference with actual volume scattering is that we assume the boundaries are diffuse and that all lighting is coming through this boundary from outside the volume. This gives much more accurate results for thin features and low density. Some challenges remain however: * Significantly more noisy than BSSRDF. Adding Dwivedi sampling may help here, but it's unclear still how much it helps in real world cases. * Due to this being a volumetric method, geometry like eyes or mouth can darken the skin on the outside. We may be able to reduce this effect, or users can compensate for it by reducing the scattering radius in such areas. * Sharp corners are quite bright. This matches actual volume rendering and results in some other renderers, but maybe not so much real world objects. Differential Revision: https://developer.blender.org/D3054
132 lines
4.5 KiB
C++
132 lines
4.5 KiB
C++
/*
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* Adapted from Open Shading Language with this license:
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*
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* Copyright (c) 2009-2010 Sony Pictures Imageworks Inc., et al.
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* All Rights Reserved.
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*
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* Modifications Copyright 2011, Blender Foundation.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions are
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* met:
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* * Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* * Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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* * Neither the name of Sony Pictures Imageworks nor the names of its
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* contributors may be used to endorse or promote products derived from
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* this software without specific prior written permission.
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* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
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* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
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* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
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* A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
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* OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
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* SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
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* LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
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* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
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* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
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* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
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* OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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*/
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#include <OSL/genclosure.h>
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#include "kernel/kernel_compat_cpu.h"
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#include "kernel/osl/osl_closures.h"
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#include "kernel/kernel_types.h"
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#include "kernel/kernel_montecarlo.h"
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#include "kernel/closure/alloc.h"
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#include "kernel/closure/bsdf_util.h"
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#include "kernel/closure/bsdf_diffuse.h"
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#include "kernel/closure/bsdf_principled_diffuse.h"
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#include "kernel/closure/bssrdf.h"
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CCL_NAMESPACE_BEGIN
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using namespace OSL;
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static ustring u_cubic("cubic");
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static ustring u_gaussian("gaussian");
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static ustring u_burley("burley");
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static ustring u_principled("principled");
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static ustring u_random_walk("random_walk");
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class CBSSRDFClosure : public CClosurePrimitive {
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public:
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Bssrdf params;
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ustring method;
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CBSSRDFClosure()
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{
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params.texture_blur = 0.0f;
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params.sharpness = 0.0f;
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params.roughness = 0.0f;
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}
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void setup(ShaderData *sd, int path_flag, float3 weight)
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{
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if (method == u_cubic) {
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alloc(sd, path_flag, weight, CLOSURE_BSSRDF_CUBIC_ID);
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}
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else if (method == u_gaussian) {
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alloc(sd, path_flag, weight, CLOSURE_BSSRDF_GAUSSIAN_ID);
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}
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else if (method == u_burley) {
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alloc(sd, path_flag, weight, CLOSURE_BSSRDF_BURLEY_ID);
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}
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else if (method == u_principled) {
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alloc(sd, path_flag, weight, CLOSURE_BSSRDF_PRINCIPLED_ID);
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}
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else if (method == u_random_walk) {
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alloc(sd, path_flag, weight, CLOSURE_BSSRDF_RANDOM_WALK_ID);
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}
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}
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void alloc(ShaderData *sd, int path_flag, float3 weight, ClosureType type)
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{
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Bssrdf *bssrdf = bssrdf_alloc(sd, weight);
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if(bssrdf) {
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/* disable in case of diffuse ancestor, can't see it well then and
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* adds considerably noise due to probabilities of continuing path
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* getting lower and lower */
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if(path_flag & PATH_RAY_DIFFUSE_ANCESTOR) {
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params.radius = make_float3(0.0f, 0.0f, 0.0f);
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}
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/* create one closure per color channel */
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bssrdf->radius = params.radius;
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bssrdf->albedo = params.albedo;
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bssrdf->texture_blur = params.texture_blur;
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bssrdf->sharpness = params.sharpness;
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bssrdf->N = params.N;
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bssrdf->roughness = params.roughness;
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sd->flag |= bssrdf_setup(sd, bssrdf, (ClosureType)type);
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}
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}
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};
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ClosureParam *closure_bssrdf_params()
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{
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static ClosureParam params[] = {
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CLOSURE_STRING_PARAM(CBSSRDFClosure, method),
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CLOSURE_FLOAT3_PARAM(CBSSRDFClosure, params.N),
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CLOSURE_FLOAT3_PARAM(CBSSRDFClosure, params.radius),
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CLOSURE_FLOAT3_PARAM(CBSSRDFClosure, params.albedo),
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CLOSURE_FLOAT_KEYPARAM(CBSSRDFClosure, params.texture_blur, "texture_blur"),
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CLOSURE_FLOAT_KEYPARAM(CBSSRDFClosure, params.sharpness, "sharpness"),
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CLOSURE_FLOAT_KEYPARAM(CBSSRDFClosure, params.roughness, "roughness"),
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CLOSURE_STRING_KEYPARAM(CBSSRDFClosure, label, "label"),
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CLOSURE_FINISH_PARAM(CBSSRDFClosure)
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};
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return params;
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}
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CCLOSURE_PREPARE(closure_bssrdf_prepare, CBSSRDFClosure)
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CCL_NAMESPACE_END
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