forked from bartvdbraak/blender
244 lines
7.7 KiB
C++
244 lines
7.7 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 <OpenImageIO/fmath.h>
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#include <OSL/genclosure.h>
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#include "osl_closures.h"
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#include "util_math.h"
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CCL_NAMESPACE_BEGIN
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using namespace OSL;
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class WestinBackscatterClosure : public BSDFClosure {
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public:
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Vec3 m_N;
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float m_roughness;
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float m_invroughness;
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WestinBackscatterClosure() : BSDFClosure(Labels::GLOSSY) {}
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void setup()
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{
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m_roughness = clamp(m_roughness, 1e-5f, 1.0f);
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m_invroughness = m_roughness > 0 ? 1 / m_roughness : 0;
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}
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bool mergeable(const ClosurePrimitive *other) const {
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const WestinBackscatterClosure *comp = (const WestinBackscatterClosure *)other;
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return m_N == comp->m_N && m_roughness == comp->m_roughness &&
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BSDFClosure::mergeable(other);
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}
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size_t memsize() const { return sizeof(*this); }
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const char *name() const { return "westin_backscatter"; }
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void print_on(std::ostream &out) const
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{
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out << name() << " (";
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out << "(" << m_N[0] << ", " << m_N[1] << ", " << m_N[2] << "), ";
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out << m_roughness;
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out << ")";
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}
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float albedo(const Vec3 &omega_out) const
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{
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return 1.0f;
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}
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Color3 eval_reflect(const Vec3 &omega_out, const Vec3 &omega_in, float &pdf) const
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{
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// pdf is implicitly 0 (no indirect sampling)
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float cosNO = m_N.dot(omega_out);
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float cosNI = m_N.dot(omega_in);
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if (cosNO > 0 && cosNI > 0) {
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float cosine = omega_out.dot(omega_in);
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pdf = cosine > 0 ? (m_invroughness + 1) * powf(cosine, m_invroughness) : 0;
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pdf *= 0.5f * float(M_1_PI);
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return Color3(pdf, pdf, pdf);
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}
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return Color3(0, 0, 0);
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}
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Color3 eval_transmit(const Vec3 &omega_out, const Vec3 &omega_in, float &pdf) const
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{
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return Color3(0, 0, 0);
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}
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ustring sample(const Vec3 &Ng,
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const Vec3 &omega_out, const Vec3 &domega_out_dx, const Vec3 &domega_out_dy,
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float randu, float randv,
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Vec3 &omega_in, Vec3 &domega_in_dx, Vec3 &domega_in_dy,
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float &pdf, Color3 &eval) const
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{
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float cosNO = m_N.dot(omega_out);
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if (cosNO > 0) {
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domega_in_dx = domega_out_dx;
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domega_in_dy = domega_out_dy;
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Vec3 T, B;
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make_orthonormals(omega_out, T, B);
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float phi = 2 * (float) M_PI * randu;
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float cosTheta = powf(randv, 1 / (m_invroughness + 1));
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float sinTheta2 = 1 - cosTheta * cosTheta;
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float sinTheta = sinTheta2 > 0 ? sqrtf(sinTheta2) : 0;
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omega_in = (cosf(phi) * sinTheta) * T +
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(sinf(phi) * sinTheta) * B +
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(cosTheta) * omega_out;
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if (Ng.dot(omega_in) > 0)
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{
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// common terms for pdf and eval
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float cosNI = m_N.dot(omega_in);
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// make sure the direction we chose is still in the right hemisphere
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if (cosNI > 0)
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{
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pdf = 0.5f * (float) M_1_PI * powf(cosTheta, m_invroughness);
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pdf = (m_invroughness + 1) * pdf;
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eval.setValue(pdf, pdf, pdf);
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// Since there is some blur to this reflection, make the
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// derivatives a bit bigger. In theory this varies with the
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// exponent but the exact relationship is complex and
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// requires more ops than are practical.
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domega_in_dx *= 10;
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domega_in_dy *= 10;
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}
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}
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}
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return Labels::REFLECT;
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}
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};
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class WestinSheenClosure : public BSDFClosure {
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public:
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Vec3 m_N;
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float m_edginess;
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// float m_normalization;
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WestinSheenClosure() : BSDFClosure(Labels::DIFFUSE) {}
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void setup() {};
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bool mergeable(const ClosurePrimitive *other) const {
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const WestinSheenClosure *comp = (const WestinSheenClosure *)other;
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return m_N == comp->m_N && m_edginess == comp->m_edginess &&
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BSDFClosure::mergeable(other);
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}
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size_t memsize() const { return sizeof(*this); }
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const char *name() const { return "westin_sheen"; }
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void print_on(std::ostream &out) const
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{
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out << name() << " (";
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out << "(" << m_N[0] << ", " << m_N[1] << ", " << m_N[2] << "), ";
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out << m_edginess;
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out << ")";
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}
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float albedo(const Vec3 &omega_out) const
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{
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return 1.0f;
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}
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Color3 eval_reflect(const Vec3 &omega_out, const Vec3 &omega_in, float &pdf) const
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{
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// pdf is implicitly 0 (no indirect sampling)
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float cosNO = m_N.dot(omega_out);
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float cosNI = m_N.dot(omega_in);
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if (cosNO > 0 && cosNI > 0) {
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float sinNO2 = 1 - cosNO * cosNO;
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pdf = cosNI * float(M_1_PI);
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float westin = sinNO2 > 0 ? powf(sinNO2, 0.5f * m_edginess) * pdf : 0;
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return Color3(westin, westin, westin);
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}
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return Color3(0, 0, 0);
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}
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Color3 eval_transmit(const Vec3 &omega_out, const Vec3 &omega_in, float &pdf) const
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{
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return Color3(0, 0, 0);
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}
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ustring sample(const Vec3 &Ng,
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const Vec3 &omega_out, const Vec3 &domega_out_dx, const Vec3 &domega_out_dy,
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float randu, float randv,
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Vec3 &omega_in, Vec3 &domega_in_dx, Vec3 &domega_in_dy,
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float &pdf, Color3 &eval) const
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{
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// we are viewing the surface from the right side - send a ray out with cosine
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// distribution over the hemisphere
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sample_cos_hemisphere(m_N, omega_out, randu, randv, omega_in, pdf);
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if (Ng.dot(omega_in) > 0) {
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// TODO: account for sheen when sampling
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float cosNO = m_N.dot(omega_out);
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float sinNO2 = 1 - cosNO * cosNO;
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float westin = sinNO2 > 0 ? powf(sinNO2, 0.5f * m_edginess) * pdf : 0;
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eval.setValue(westin, westin, westin);
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// TODO: find a better approximation for the diffuse bounce
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domega_in_dx = (2 * m_N.dot(domega_out_dx)) * m_N - domega_out_dx;
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domega_in_dy = (2 * m_N.dot(domega_out_dy)) * m_N - domega_out_dy;
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domega_in_dx *= 125;
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domega_in_dy *= 125;
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}
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else {
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pdf = 0;
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}
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return Labels::REFLECT;
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}
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};
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ClosureParam bsdf_westin_backscatter_params[] = {
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CLOSURE_VECTOR_PARAM(WestinBackscatterClosure, m_N),
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CLOSURE_FLOAT_PARAM(WestinBackscatterClosure, m_roughness),
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CLOSURE_STRING_KEYPARAM("label"),
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CLOSURE_FINISH_PARAM(WestinBackscatterClosure)
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};
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ClosureParam bsdf_westin_sheen_params[] = {
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CLOSURE_VECTOR_PARAM(WestinSheenClosure, m_N),
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CLOSURE_FLOAT_PARAM(WestinSheenClosure, m_edginess),
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CLOSURE_STRING_KEYPARAM("label"),
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CLOSURE_FINISH_PARAM(WestinSheenClosure)
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};
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CLOSURE_PREPARE(bsdf_westin_backscatter_prepare, WestinBackscatterClosure)
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CLOSURE_PREPARE(bsdf_westin_sheen_prepare, WestinSheenClosure)
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CCL_NAMESPACE_END
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