forked from bartvdbraak/blender
534 lines
24 KiB
C++
534 lines
24 KiB
C++
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/*
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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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using namespace OSL;
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CCL_NAMESPACE_BEGIN
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// TODO: fresnel_dielectric is only used for derivatives, could be optimized
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// TODO: refactor these two classes so they share everything by the microfacet
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// distribution terms
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// microfacet model with GGX facet distribution
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// see http://www.graphics.cornell.edu/~bjw/microfacetbsdf.pdf
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template <int Refractive = 0>
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class MicrofacetGGXClosure : public BSDFClosure {
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public:
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Vec3 m_N;
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float m_ag; // width parameter (roughness)
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float m_eta; // index of refraction (for fresnel term)
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MicrofacetGGXClosure() : BSDFClosure(Labels::GLOSSY, Refractive ? Back : Front) { m_eta = 1.0f; }
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void setup()
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{
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m_ag = clamp(m_ag, 1e-5f, 1.0f);
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}
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bool mergeable (const ClosurePrimitive *other) const {
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const MicrofacetGGXClosure *comp = (const MicrofacetGGXClosure *)other;
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return m_N == comp->m_N && m_ag == comp->m_ag &&
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m_eta == comp->m_eta && 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 {
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return Refractive ? "microfacet_ggx_refraction" : "microfacet_ggx";
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}
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void print_on (std::ostream &out) const {
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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_ag << ", ";
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out << m_eta;
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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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if (Refractive == 1) return Color3 (0, 0, 0);
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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 (cosNI > 0 && cosNO > 0) {
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// get half vector
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Vec3 Hr = omega_in + omega_out;
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Hr.normalize();
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// eq. 20: (F*G*D)/(4*in*on)
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// eq. 33: first we calculate D(m) with m=Hr:
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float alpha2 = m_ag * m_ag;
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float cosThetaM = m_N.dot(Hr);
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float cosThetaM2 = cosThetaM * cosThetaM;
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float tanThetaM2 = (1 - cosThetaM2) / cosThetaM2;
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float cosThetaM4 = cosThetaM2 * cosThetaM2;
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float D = alpha2 / ((float) M_PI * cosThetaM4 * (alpha2 + tanThetaM2) * (alpha2 + tanThetaM2));
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// eq. 34: now calculate G1(i,m) and G1(o,m)
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float G1o = 2 / (1 + sqrtf(1 + alpha2 * (1 - cosNO * cosNO) / (cosNO * cosNO)));
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float G1i = 2 / (1 + sqrtf(1 + alpha2 * (1 - cosNI * cosNI) / (cosNI * cosNI)));
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float G = G1o * G1i;
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float out = (G * D) * 0.25f / cosNO;
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// eq. 24
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float pm = D * cosThetaM;
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// convert into pdf of the sampled direction
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// eq. 38 - but see also:
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// eq. 17 in http://www.graphics.cornell.edu/~bjw/wardnotes.pdf
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pdf = pm * 0.25f / Hr.dot(omega_out);
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return Color3 (out, out, out);
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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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if (Refractive == 0) return Color3 (0, 0, 0);
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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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return Color3 (0, 0, 0); // vectors on same side -- not possible
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// compute half-vector of the refraction (eq. 16)
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Vec3 ht = -(m_eta * omega_in + omega_out);
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Vec3 Ht = ht; Ht.normalize();
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float cosHO = Ht.dot(omega_out);
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float cosHI = Ht.dot(omega_in);
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// eq. 33: first we calculate D(m) with m=Ht:
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float alpha2 = m_ag * m_ag;
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float cosThetaM = m_N.dot(Ht);
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float cosThetaM2 = cosThetaM * cosThetaM;
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float tanThetaM2 = (1 - cosThetaM2) / cosThetaM2;
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float cosThetaM4 = cosThetaM2 * cosThetaM2;
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float D = alpha2 / ((float) M_PI * cosThetaM4 * (alpha2 + tanThetaM2) * (alpha2 + tanThetaM2));
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// eq. 34: now calculate G1(i,m) and G1(o,m)
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float G1o = 2 / (1 + sqrtf(1 + alpha2 * (1 - cosNO * cosNO) / (cosNO * cosNO)));
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float G1i = 2 / (1 + sqrtf(1 + alpha2 * (1 - cosNI * cosNI) / (cosNI * cosNI)));
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float G = G1o * G1i;
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// probability
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float invHt2 = 1 / ht.dot(ht);
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pdf = D * fabsf(cosThetaM) * (fabsf(cosHI) * (m_eta * m_eta)) * invHt2;
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float out = (fabsf(cosHI * cosHO) * (m_eta * m_eta) * (G * D) * invHt2) / cosNO;
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return Color3 (out, out, out);
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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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Vec3 X, Y, Z = m_N;
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make_orthonormals(Z, X, Y);
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// generate a random microfacet normal m
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// eq. 35,36:
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// we take advantage of cos(atan(x)) == 1/sqrt(1+x^2)
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// and sin(atan(x)) == x/sqrt(1+x^2)
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float alpha2 = m_ag * m_ag;
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float tanThetaM2 = alpha2 * randu / (1 - randu);
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float cosThetaM = 1 / sqrtf(1 + tanThetaM2);
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float sinThetaM = cosThetaM * sqrtf(tanThetaM2);
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float phiM = 2 * float(M_PI) * randv;
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Vec3 m = (cosf(phiM) * sinThetaM) * X +
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(sinf(phiM) * sinThetaM) * Y +
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cosThetaM * Z;
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if (Refractive == 0) {
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float cosMO = m.dot(omega_out);
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if (cosMO > 0) {
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// eq. 39 - compute actual reflected direction
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omega_in = 2 * cosMO * m - omega_out;
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if (Ng.dot(omega_in) > 0) {
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// microfacet normal is visible to this ray
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// eq. 33
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float cosThetaM2 = cosThetaM * cosThetaM;
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float cosThetaM4 = cosThetaM2 * cosThetaM2;
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float D = alpha2 / (float(M_PI) * cosThetaM4 * (alpha2 + tanThetaM2) * (alpha2 + tanThetaM2));
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// eq. 24
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float pm = D * cosThetaM;
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// convert into pdf of the sampled direction
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// eq. 38 - but see also:
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// eq. 17 in http://www.graphics.cornell.edu/~bjw/wardnotes.pdf
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pdf = pm * 0.25f / cosMO;
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// eval BRDF*cosNI
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float cosNI = m_N.dot(omega_in);
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// eq. 34: now calculate G1(i,m) and G1(o,m)
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float G1o = 2 / (1 + sqrtf(1 + alpha2 * (1 - cosNO * cosNO) / (cosNO * cosNO)));
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float G1i = 2 / (1 + sqrtf(1 + alpha2 * (1 - cosNI * cosNI) / (cosNI * cosNI)));
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float G = G1o * G1i;
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// eq. 20: (F*G*D)/(4*in*on)
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float out = (G * D) * 0.25f / cosNO;
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eval.setValue(out, out, out);
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domega_in_dx = (2 * m.dot(domega_out_dx)) * m - domega_out_dx;
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domega_in_dy = (2 * m.dot(domega_out_dy)) * m - domega_out_dy;
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/* disabled for now - gives texture filtering problems */
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#if 0
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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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// roughness 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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#endif
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}
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}
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} else {
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// CAUTION: the i and o variables are inverted relative to the paper
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// eq. 39 - compute actual refractive direction
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Vec3 R, dRdx, dRdy;
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Vec3 T, dTdx, dTdy;
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bool inside;
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fresnel_dielectric(m_eta, m, omega_out, domega_out_dx, domega_out_dy,
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R, dRdx, dRdy,
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T, dTdx, dTdy,
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inside);
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if (!inside) {
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omega_in = T;
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domega_in_dx = dTdx;
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domega_in_dy = dTdy;
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// eq. 33
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float cosThetaM2 = cosThetaM * cosThetaM;
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float cosThetaM4 = cosThetaM2 * cosThetaM2;
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float D = alpha2 / (float(M_PI) * cosThetaM4 * (alpha2 + tanThetaM2) * (alpha2 + tanThetaM2));
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// eq. 24
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float pm = D * cosThetaM;
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// eval BRDF*cosNI
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float cosNI = m_N.dot(omega_in);
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// eq. 34: now calculate G1(i,m) and G1(o,m)
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float G1o = 2 / (1 + sqrtf(1 + alpha2 * (1 - cosNO * cosNO) / (cosNO * cosNO)));
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float G1i = 2 / (1 + sqrtf(1 + alpha2 * (1 - cosNI * cosNI) / (cosNI * cosNI)));
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float G = G1o * G1i;
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// eq. 21
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float cosHI = m.dot(omega_in);
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float cosHO = m.dot(omega_out);
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float Ht2 = m_eta * cosHI + cosHO;
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Ht2 *= Ht2;
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float out = (fabsf(cosHI * cosHO) * (m_eta * m_eta) * (G * D)) / (cosNO * Ht2);
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// eq. 38 and eq. 17
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pdf = pm * (m_eta * m_eta) * fabsf(cosHI) / Ht2;
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eval.setValue(out, out, out);
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/* disabled for now - gives texture filtering problems */
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#if 0
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// Since there is some blur to this refraction, make the
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// derivatives a bit bigger. In theory this varies with the
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// roughness 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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#endif
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}
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}
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}
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return Refractive ? Labels::TRANSMIT : Labels::REFLECT;
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}
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};
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// microfacet model with Beckmann facet distribution
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// see http://www.graphics.cornell.edu/~bjw/microfacetbsdf.pdf
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template <int Refractive = 0>
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class MicrofacetBeckmannClosure : public BSDFClosure {
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public:
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Vec3 m_N;
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float m_ab; // width parameter (roughness)
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float m_eta; // index of refraction (for fresnel term)
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MicrofacetBeckmannClosure() : BSDFClosure(Labels::GLOSSY, Refractive ? Back : Front) { }
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void setup()
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{
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m_ab = clamp(m_ab, 1e-5f, 1.0f);
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}
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bool mergeable (const ClosurePrimitive *other) const {
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const MicrofacetBeckmannClosure *comp = (const MicrofacetBeckmannClosure *)other;
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return m_N == comp->m_N && m_ab == comp->m_ab &&
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m_eta == comp->m_eta && 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 {
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return Refractive ? "microfacet_beckmann_refraction"
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: "microfacet_beckmann";
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}
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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_ab << ", ";
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out << m_eta;
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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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if (Refractive == 1) return Color3 (0, 0, 0);
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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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// get half vector
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Vec3 Hr = omega_in + omega_out;
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Hr.normalize();
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// eq. 20: (F*G*D)/(4*in*on)
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// eq. 25: first we calculate D(m) with m=Hr:
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||
|
|
float alpha2 = m_ab * m_ab;
|
||
|
|
float cosThetaM = m_N.dot(Hr);
|
||
|
|
float cosThetaM2 = cosThetaM * cosThetaM;
|
||
|
|
float tanThetaM2 = (1 - cosThetaM2) / cosThetaM2;
|
||
|
|
float cosThetaM4 = cosThetaM2 * cosThetaM2;
|
||
|
|
float D = expf(-tanThetaM2 / alpha2) / (float(M_PI) * alpha2 * cosThetaM4);
|
||
|
|
// eq. 26, 27: now calculate G1(i,m) and G1(o,m)
|
||
|
|
float ao = 1 / (m_ab * sqrtf((1 - cosNO * cosNO) / (cosNO * cosNO)));
|
||
|
|
float ai = 1 / (m_ab * sqrtf((1 - cosNI * cosNI) / (cosNI * cosNI)));
|
||
|
|
float G1o = ao < 1.6f ? (3.535f * ao + 2.181f * ao * ao) / (1 + 2.276f * ao + 2.577f * ao * ao) : 1.0f;
|
||
|
|
float G1i = ai < 1.6f ? (3.535f * ai + 2.181f * ai * ai) / (1 + 2.276f * ai + 2.577f * ai * ai) : 1.0f;
|
||
|
|
float G = G1o * G1i;
|
||
|
|
float out = (G * D) * 0.25f / cosNO;
|
||
|
|
// eq. 24
|
||
|
|
float pm = D * cosThetaM;
|
||
|
|
// convert into pdf of the sampled direction
|
||
|
|
// eq. 38 - but see also:
|
||
|
|
// eq. 17 in http://www.graphics.cornell.edu/~bjw/wardnotes.pdf
|
||
|
|
pdf = pm * 0.25f / Hr.dot(omega_out);
|
||
|
|
return Color3 (out, out, out);
|
||
|
|
}
|
||
|
|
return Color3 (0, 0, 0);
|
||
|
|
}
|
||
|
|
|
||
|
|
Color3 eval_transmit (const Vec3 &omega_out, const Vec3 &omega_in, float& pdf) const
|
||
|
|
{
|
||
|
|
if (Refractive == 0) return Color3 (0, 0, 0);
|
||
|
|
float cosNO = m_N.dot(omega_out);
|
||
|
|
float cosNI = m_N.dot(omega_in);
|
||
|
|
if (cosNO <= 0 || cosNI >= 0)
|
||
|
|
return Color3 (0, 0, 0);
|
||
|
|
// compute half-vector of the refraction (eq. 16)
|
||
|
|
Vec3 ht = -(m_eta * omega_in + omega_out);
|
||
|
|
Vec3 Ht = ht; Ht.normalize();
|
||
|
|
float cosHO = Ht.dot(omega_out);
|
||
|
|
|
||
|
|
float cosHI = Ht.dot(omega_in);
|
||
|
|
// eq. 33: first we calculate D(m) with m=Ht:
|
||
|
|
float alpha2 = m_ab * m_ab;
|
||
|
|
float cosThetaM = m_N.dot(Ht);
|
||
|
|
float cosThetaM2 = cosThetaM * cosThetaM;
|
||
|
|
float tanThetaM2 = (1 - cosThetaM2) / cosThetaM2;
|
||
|
|
float cosThetaM4 = cosThetaM2 * cosThetaM2;
|
||
|
|
float D = expf(-tanThetaM2 / alpha2) / (float(M_PI) * alpha2 * cosThetaM4);
|
||
|
|
// eq. 26, 27: now calculate G1(i,m) and G1(o,m)
|
||
|
|
float ao = 1 / (m_ab * sqrtf((1 - cosNO * cosNO) / (cosNO * cosNO)));
|
||
|
|
float ai = 1 / (m_ab * sqrtf((1 - cosNI * cosNI) / (cosNI * cosNI)));
|
||
|
|
float G1o = ao < 1.6f ? (3.535f * ao + 2.181f * ao * ao) / (1 + 2.276f * ao + 2.577f * ao * ao) : 1.0f;
|
||
|
|
float G1i = ai < 1.6f ? (3.535f * ai + 2.181f * ai * ai) / (1 + 2.276f * ai + 2.577f * ai * ai) : 1.0f;
|
||
|
|
float G = G1o * G1i;
|
||
|
|
// probability
|
||
|
|
float invHt2 = 1 / ht.dot(ht);
|
||
|
|
pdf = D * fabsf(cosThetaM) * (fabsf(cosHI) * (m_eta * m_eta)) * invHt2;
|
||
|
|
float out = (fabsf(cosHI * cosHO) * (m_eta * m_eta) * (G * D) * invHt2) / cosNO;
|
||
|
|
return Color3 (out, out, out);
|
||
|
|
}
|
||
|
|
|
||
|
|
ustring sample (const Vec3 &Ng,
|
||
|
|
const Vec3 &omega_out, const Vec3 &domega_out_dx, const Vec3 &domega_out_dy,
|
||
|
|
float randu, float randv,
|
||
|
|
Vec3 &omega_in, Vec3 &domega_in_dx, Vec3 &domega_in_dy,
|
||
|
|
float &pdf, Color3 &eval) const
|
||
|
|
{
|
||
|
|
float cosNO = m_N.dot(omega_out);
|
||
|
|
if (cosNO > 0) {
|
||
|
|
Vec3 X, Y, Z = m_N;
|
||
|
|
make_orthonormals(Z, X, Y);
|
||
|
|
// generate a random microfacet normal m
|
||
|
|
// eq. 35,36:
|
||
|
|
// we take advantage of cos(atan(x)) == 1/sqrt(1+x^2)
|
||
|
|
// and sin(atan(x)) == x/sqrt(1+x^2)
|
||
|
|
float alpha2 = m_ab * m_ab;
|
||
|
|
float tanThetaM = sqrtf(-alpha2 * logf(1 - randu));
|
||
|
|
float cosThetaM = 1 / sqrtf(1 + tanThetaM * tanThetaM);
|
||
|
|
float sinThetaM = cosThetaM * tanThetaM;
|
||
|
|
float phiM = 2 * float(M_PI) * randv;
|
||
|
|
Vec3 m = (cosf(phiM) * sinThetaM) * X +
|
||
|
|
(sinf(phiM) * sinThetaM) * Y +
|
||
|
|
cosThetaM * Z;
|
||
|
|
if (Refractive == 0) {
|
||
|
|
float cosMO = m.dot(omega_out);
|
||
|
|
if (cosMO > 0) {
|
||
|
|
// eq. 39 - compute actual reflected direction
|
||
|
|
omega_in = 2 * cosMO * m - omega_out;
|
||
|
|
if (Ng.dot(omega_in) > 0) {
|
||
|
|
// microfacet normal is visible to this ray
|
||
|
|
// eq. 25
|
||
|
|
float cosThetaM2 = cosThetaM * cosThetaM;
|
||
|
|
float tanThetaM2 = tanThetaM * tanThetaM;
|
||
|
|
float cosThetaM4 = cosThetaM2 * cosThetaM2;
|
||
|
|
float D = expf(-tanThetaM2 / alpha2) / (float(M_PI) * alpha2 * cosThetaM4);
|
||
|
|
// eq. 24
|
||
|
|
float pm = D * cosThetaM;
|
||
|
|
// convert into pdf of the sampled direction
|
||
|
|
// eq. 38 - but see also:
|
||
|
|
// eq. 17 in http://www.graphics.cornell.edu/~bjw/wardnotes.pdf
|
||
|
|
pdf = pm * 0.25f / cosMO;
|
||
|
|
// Eval BRDF*cosNI
|
||
|
|
float cosNI = m_N.dot(omega_in);
|
||
|
|
// eq. 26, 27: now calculate G1(i,m) and G1(o,m)
|
||
|
|
float ao = 1 / (m_ab * sqrtf((1 - cosNO * cosNO) / (cosNO * cosNO)));
|
||
|
|
float ai = 1 / (m_ab * sqrtf((1 - cosNI * cosNI) / (cosNI * cosNI)));
|
||
|
|
float G1o = ao < 1.6f ? (3.535f * ao + 2.181f * ao * ao) / (1 + 2.276f * ao + 2.577f * ao * ao) : 1.0f;
|
||
|
|
float G1i = ai < 1.6f ? (3.535f * ai + 2.181f * ai * ai) / (1 + 2.276f * ai + 2.577f * ai * ai) : 1.0f;
|
||
|
|
float G = G1o * G1i;
|
||
|
|
// eq. 20: (F*G*D)/(4*in*on)
|
||
|
|
float out = (G * D) * 0.25f / cosNO;
|
||
|
|
eval.setValue(out, out, out);
|
||
|
|
domega_in_dx = (2 * m.dot(domega_out_dx)) * m - domega_out_dx;
|
||
|
|
domega_in_dy = (2 * m.dot(domega_out_dy)) * m - domega_out_dy;
|
||
|
|
|
||
|
|
/* disabled for now - gives texture filtering problems */
|
||
|
|
#if 0
|
||
|
|
// Since there is some blur to this reflection, make the
|
||
|
|
// derivatives a bit bigger. In theory this varies with the
|
||
|
|
// roughness but the exact relationship is complex and
|
||
|
|
// requires more ops than are practical.
|
||
|
|
domega_in_dx *= 10;
|
||
|
|
domega_in_dy *= 10;
|
||
|
|
#endif
|
||
|
|
}
|
||
|
|
}
|
||
|
|
} else {
|
||
|
|
// CAUTION: the i and o variables are inverted relative to the paper
|
||
|
|
// eq. 39 - compute actual refractive direction
|
||
|
|
Vec3 R, dRdx, dRdy;
|
||
|
|
Vec3 T, dTdx, dTdy;
|
||
|
|
bool inside;
|
||
|
|
fresnel_dielectric(m_eta, m, omega_out, domega_out_dx, domega_out_dy,
|
||
|
|
R, dRdx, dRdy,
|
||
|
|
T, dTdx, dTdy,
|
||
|
|
inside);
|
||
|
|
if (!inside) {
|
||
|
|
omega_in = T;
|
||
|
|
domega_in_dx = dTdx;
|
||
|
|
domega_in_dy = dTdy;
|
||
|
|
// eq. 33
|
||
|
|
float cosThetaM2 = cosThetaM * cosThetaM;
|
||
|
|
float tanThetaM2 = tanThetaM * tanThetaM;
|
||
|
|
float cosThetaM4 = cosThetaM2 * cosThetaM2;
|
||
|
|
float D = expf(-tanThetaM2 / alpha2) / (float(M_PI) * alpha2 * cosThetaM4);
|
||
|
|
// eq. 24
|
||
|
|
float pm = D * cosThetaM;
|
||
|
|
// eval BRDF*cosNI
|
||
|
|
float cosNI = m_N.dot(omega_in);
|
||
|
|
// eq. 26, 27: now calculate G1(i,m) and G1(o,m)
|
||
|
|
float ao = 1 / (m_ab * sqrtf((1 - cosNO * cosNO) / (cosNO * cosNO)));
|
||
|
|
float ai = 1 / (m_ab * sqrtf((1 - cosNI * cosNI) / (cosNI * cosNI)));
|
||
|
|
float G1o = ao < 1.6f ? (3.535f * ao + 2.181f * ao * ao) / (1 + 2.276f * ao + 2.577f * ao * ao) : 1.0f;
|
||
|
|
float G1i = ai < 1.6f ? (3.535f * ai + 2.181f * ai * ai) / (1 + 2.276f * ai + 2.577f * ai * ai) : 1.0f;
|
||
|
|
float G = G1o * G1i;
|
||
|
|
// eq. 21
|
||
|
|
float cosHI = m.dot(omega_in);
|
||
|
|
float cosHO = m.dot(omega_out);
|
||
|
|
float Ht2 = m_eta * cosHI + cosHO;
|
||
|
|
Ht2 *= Ht2;
|
||
|
|
float out = (fabsf(cosHI * cosHO) * (m_eta * m_eta) * (G * D)) / (cosNO * Ht2);
|
||
|
|
// eq. 38 and eq. 17
|
||
|
|
pdf = pm * (m_eta * m_eta) * fabsf(cosHI) / Ht2;
|
||
|
|
eval.setValue(out, out, out);
|
||
|
|
|
||
|
|
/* disabled for now - gives texture filtering problems */
|
||
|
|
#if 0
|
||
|
|
// Since there is some blur to this refraction, make the
|
||
|
|
// derivatives a bit bigger. In theory this varies with the
|
||
|
|
// roughness but the exact relationship is complex and
|
||
|
|
// requires more ops than are practical.
|
||
|
|
domega_in_dx *= 10;
|
||
|
|
domega_in_dy *= 10;
|
||
|
|
#endif
|
||
|
|
}
|
||
|
|
}
|
||
|
|
}
|
||
|
|
return Refractive ? Labels::TRANSMIT : Labels::REFLECT;
|
||
|
|
}
|
||
|
|
};
|
||
|
|
|
||
|
|
|
||
|
|
|
||
|
|
ClosureParam bsdf_microfacet_ggx_params[] = {
|
||
|
|
CLOSURE_VECTOR_PARAM(MicrofacetGGXClosure<0>, m_N),
|
||
|
|
CLOSURE_FLOAT_PARAM (MicrofacetGGXClosure<0>, m_ag),
|
||
|
|
CLOSURE_STRING_KEYPARAM("label"),
|
||
|
|
CLOSURE_FINISH_PARAM(MicrofacetGGXClosure<0>) };
|
||
|
|
|
||
|
|
ClosureParam bsdf_microfacet_ggx_refraction_params[] = {
|
||
|
|
CLOSURE_VECTOR_PARAM(MicrofacetGGXClosure<1>, m_N),
|
||
|
|
CLOSURE_FLOAT_PARAM (MicrofacetGGXClosure<1>, m_ag),
|
||
|
|
CLOSURE_FLOAT_PARAM (MicrofacetGGXClosure<1>, m_eta),
|
||
|
|
CLOSURE_STRING_KEYPARAM("label"),
|
||
|
|
CLOSURE_FINISH_PARAM(MicrofacetGGXClosure<1>) };
|
||
|
|
|
||
|
|
ClosureParam bsdf_microfacet_beckmann_params[] = {
|
||
|
|
CLOSURE_VECTOR_PARAM(MicrofacetBeckmannClosure<0>, m_N),
|
||
|
|
CLOSURE_FLOAT_PARAM (MicrofacetBeckmannClosure<0>, m_ab),
|
||
|
|
CLOSURE_STRING_KEYPARAM("label"),
|
||
|
|
CLOSURE_FINISH_PARAM(MicrofacetBeckmannClosure<0>) };
|
||
|
|
|
||
|
|
ClosureParam bsdf_microfacet_beckmann_refraction_params[] = {
|
||
|
|
CLOSURE_VECTOR_PARAM(MicrofacetBeckmannClosure<1>, m_N),
|
||
|
|
CLOSURE_FLOAT_PARAM (MicrofacetBeckmannClosure<1>, m_ab),
|
||
|
|
CLOSURE_FLOAT_PARAM (MicrofacetBeckmannClosure<1>, m_eta),
|
||
|
|
CLOSURE_STRING_KEYPARAM("label"),
|
||
|
|
CLOSURE_FINISH_PARAM(MicrofacetBeckmannClosure<1>) };
|
||
|
|
|
||
|
|
CLOSURE_PREPARE(bsdf_microfacet_ggx_prepare, MicrofacetGGXClosure<0>)
|
||
|
|
CLOSURE_PREPARE(bsdf_microfacet_ggx_refraction_prepare, MicrofacetGGXClosure<1>)
|
||
|
|
CLOSURE_PREPARE(bsdf_microfacet_beckmann_prepare, MicrofacetBeckmannClosure<0>)
|
||
|
|
CLOSURE_PREPARE(bsdf_microfacet_beckmann_refraction_prepare, MicrofacetBeckmannClosure<1>)
|
||
|
|
|
||
|
|
CCL_NAMESPACE_END
|
||
|
|
|