forked from bartvdbraak/blender
23c276832b
This commit adds a new distribution to the Glossy, Anisotropic and Glass BSDFs that implements the multiple-scattering microfacet model described in the paper "Multiple-Scattering Microfacet BSDFs with the Smith Model". Essentially, the improvement is that unlike classical GGX, which only models single scattering and assumes the contribution of multiple bounces to be zero, this new model performs a random walk on the microsurface until the ray leaves it again, which ensures perfect energy conservation. In practise, this means that the "darkening problem" - GGX materials becoming darker with increasing roughness - is solved in a physically correct and efficient way. The downside of this model is that it has no (known) analytic expression for evalation. However, it can be evaluated stochastically, and although the correct PDF isn't known either, the properties of MIS and the balance heuristic guarantee an unbiased result at the cost of slightly higher noise. Reviewers: dingto, #cycles, brecht Reviewed By: dingto, #cycles, brecht Subscribers: bliblubli, ace_dragon, gregzaal, brecht, harvester, dingto, marcog, swerner, jtheninja, Blendify, nutel Differential Revision: https://developer.blender.org/D2002
248 lines
8.1 KiB
C++
248 lines
8.1 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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#ifndef __OSL_CLOSURES_H__
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#define __OSL_CLOSURES_H__
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#include "util_types.h"
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#include "kernel_types.h"
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#include <OSL/oslclosure.h>
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#include <OSL/oslexec.h>
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#include <OSL/genclosure.h>
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CCL_NAMESPACE_BEGIN
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OSL::ClosureParam *closure_emission_params();
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OSL::ClosureParam *closure_background_params();
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OSL::ClosureParam *closure_holdout_params();
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OSL::ClosureParam *closure_ambient_occlusion_params();
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OSL::ClosureParam *closure_bsdf_diffuse_ramp_params();
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OSL::ClosureParam *closure_bsdf_phong_ramp_params();
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OSL::ClosureParam *closure_bssrdf_cubic_params();
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OSL::ClosureParam *closure_bssrdf_gaussian_params();
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OSL::ClosureParam *closure_bssrdf_burley_params();
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OSL::ClosureParam *closure_henyey_greenstein_volume_params();
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OSL::ClosureParam *closure_bsdf_microfacet_multi_ggx_params();
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OSL::ClosureParam *closure_bsdf_microfacet_multi_ggx_glass_params();
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OSL::ClosureParam *closure_bsdf_microfacet_multi_ggx_aniso_params();
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void closure_emission_prepare(OSL::RendererServices *, int id, void *data);
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void closure_background_prepare(OSL::RendererServices *, int id, void *data);
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void closure_holdout_prepare(OSL::RendererServices *, int id, void *data);
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void closure_ambient_occlusion_prepare(OSL::RendererServices *, int id, void *data);
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void closure_bsdf_diffuse_ramp_prepare(OSL::RendererServices *, int id, void *data);
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void closure_bsdf_phong_ramp_prepare(OSL::RendererServices *, int id, void *data);
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void closure_bssrdf_cubic_prepare(OSL::RendererServices *, int id, void *data);
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void closure_bssrdf_gaussian_prepare(OSL::RendererServices *, int id, void *data);
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void closure_bssrdf_burley_prepare(OSL::RendererServices *, int id, void *data);
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void closure_henyey_greenstein_volume_prepare(OSL::RendererServices *, int id, void *data);
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void closure_bsdf_microfacet_multi_ggx_prepare(OSL::RendererServices *, int id, void *data);
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void closure_bsdf_microfacet_multi_ggx_glass_prepare(OSL::RendererServices *, int id, void *data);
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void closure_bsdf_microfacet_multi_ggx_aniso_prepare(OSL::RendererServices *, int id, void *data);
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#define CCLOSURE_PREPARE(name, classname) \
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void name(RendererServices *, int id, void *data) \
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{ \
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memset(data, 0, sizeof(classname)); \
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new (data) classname(); \
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}
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#define CCLOSURE_PREPARE_STATIC(name, classname) static CCLOSURE_PREPARE(name, classname)
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#define CLOSURE_FLOAT3_PARAM(st, fld) \
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{ TypeDesc::TypeVector, (int)reckless_offsetof(st, fld), NULL, sizeof(OSL::Vec3) }
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#define TO_VEC3(v) OSL::Vec3(v.x, v.y, v.z)
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#define TO_COLOR3(v) OSL::Color3(v.x, v.y, v.z)
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#define TO_FLOAT3(v) make_float3(v[0], v[1], v[2])
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/* Closure */
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class CClosurePrimitive {
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public:
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enum Category {
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BSDF, ///< Reflective and/or transmissive surface
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BSSRDF, ///< Sub-surface light transfer
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Emissive, ///< Light emission
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Background, ///< Background emission
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Volume, ///< Volume scattering
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Holdout, ///< Holdout from alpha
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AmbientOcclusion, ///< Ambient occlusion
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};
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CClosurePrimitive (Category category_) : category (category_) {}
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virtual ~CClosurePrimitive() {}
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virtual void setup() {}
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Category category;
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OSL::ustring label;
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};
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/* BSDF */
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class CBSDFClosure : public CClosurePrimitive {
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public:
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ShaderClosure sc;
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CBSDFClosure(int scattering) : CClosurePrimitive(BSDF),
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m_scattering_label(scattering), m_shaderdata_flag(0)
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{}
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int scattering() const { return m_scattering_label; }
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int shaderdata_flag() const { return m_shaderdata_flag; }
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virtual void blur(float roughness) = 0;
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virtual float3 eval_reflect(const float3 &omega_out, const float3 &omega_in, float &pdf) const = 0;
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virtual float3 eval_transmit(const float3 &omega_out, const float3 &omega_in, float &pdf) const = 0;
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virtual int sample(const float3 &Ng,
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const float3 &omega_out, const float3 &domega_out_dx, const float3 &domega_out_dy,
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float randu, float randv,
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float3 &omega_in, float3 &domega_in_dx, float3 &domega_in_dy,
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float &pdf, float3 &eval) const = 0;
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protected:
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int m_scattering_label;
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int m_shaderdata_flag;
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};
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#define BSDF_CLOSURE_CLASS_BEGIN(Upper, lower, svmlower, TYPE) \
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\
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class Upper##Closure : public CBSDFClosure { \
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public: \
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Upper##Closure() : CBSDFClosure(TYPE) \
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{ \
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} \
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\
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void setup() \
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{ \
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sc.prim = NULL; \
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m_shaderdata_flag = bsdf_##lower##_setup(&sc); \
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} \
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\
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void blur(float roughness) \
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{ \
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} \
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\
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float3 eval_reflect(const float3 &omega_out, const float3 &omega_in, float& pdf) const \
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{ \
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pdf = 0.0f; \
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return make_float3(0.0f, 0.0f, 0.0f); \
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} \
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\
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float3 eval_transmit(const float3 &omega_out, const float3 &omega_in, float& pdf) const \
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{ \
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pdf = 0.0f; \
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return make_float3(0.0f, 0.0f, 0.0f); \
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} \
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\
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int sample(const float3 &Ng, \
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const float3 &omega_out, const float3 &domega_out_dx, const float3 &domega_out_dy, \
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float randu, float randv, \
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float3 &omega_in, float3 &domega_in_dx, float3 &domega_in_dy, \
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float &pdf, float3 &eval) const \
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{ \
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pdf = 0; \
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return LABEL_NONE; \
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} \
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}; \
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\
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static ClosureParam *bsdf_##lower##_params() \
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{ \
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static ClosureParam params[] = {
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/* parameters */
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#define BSDF_CLOSURE_CLASS_END(Upper, lower) \
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CLOSURE_STRING_KEYPARAM(Upper##Closure, label, "label"), \
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CLOSURE_FINISH_PARAM(Upper##Closure) \
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}; \
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return params; \
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} \
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\
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CCLOSURE_PREPARE_STATIC(bsdf_##lower##_prepare, Upper##Closure)
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/* Volume */
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class CVolumeClosure : public CClosurePrimitive {
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public:
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ShaderClosure sc;
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CVolumeClosure(int scattering) : CClosurePrimitive(Volume),
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m_scattering_label(scattering), m_shaderdata_flag(0)
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{}
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~CVolumeClosure() { }
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int scattering() const { return m_scattering_label; }
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int shaderdata_flag() const { return m_shaderdata_flag; }
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protected:
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int m_scattering_label;
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int m_shaderdata_flag;
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};
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#define VOLUME_CLOSURE_CLASS_BEGIN(Upper, lower, TYPE) \
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\
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class Upper##Closure : public CVolumeClosure { \
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public: \
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Upper##Closure() : CVolumeClosure(TYPE) {} \
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\
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void setup() \
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{ \
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sc.prim = NULL; \
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m_shaderdata_flag = volume_##lower##_setup(&sc); \
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} \
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}; \
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\
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static ClosureParam *volume_##lower##_params() \
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{ \
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static ClosureParam params[] = {
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/* parameters */
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#define VOLUME_CLOSURE_CLASS_END(Upper, lower) \
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CLOSURE_STRING_KEYPARAM(Upper##Closure, label, "label"), \
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CLOSURE_FINISH_PARAM(Upper##Closure) \
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}; \
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return params; \
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} \
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\
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CCLOSURE_PREPARE_STATIC(volume_##lower##_prepare, Upper##Closure)
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CCL_NAMESPACE_END
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#endif /* __OSL_CLOSURES_H__ */
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