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Diffstat (limited to 'intern/cycles/kernel/osl/bsdf_ashikhmin_velvet.cpp')
| -rw-r--r-- | intern/cycles/kernel/osl/bsdf_ashikhmin_velvet.cpp | 175 |
1 files changed, 175 insertions, 0 deletions
diff --git a/intern/cycles/kernel/osl/bsdf_ashikhmin_velvet.cpp b/intern/cycles/kernel/osl/bsdf_ashikhmin_velvet.cpp new file mode 100644 index 00000000000..a38c5b55cf5 --- /dev/null +++ b/intern/cycles/kernel/osl/bsdf_ashikhmin_velvet.cpp @@ -0,0 +1,175 @@ +/* + * Adapted from Open Shading Language with this license: + * + * Copyright (c) 2009-2010 Sony Pictures Imageworks Inc., et al. + * All Rights Reserved. + * + * Modifications Copyright 2011, Blender Foundation. + * + * Redistribution and use in source and binary forms, with or without + * modification, are permitted provided that the following conditions are + * met: + * * Redistributions of source code must retain the above copyright + * notice, this list of conditions and the following disclaimer. + * * Redistributions in binary form must reproduce the above copyright + * notice, this list of conditions and the following disclaimer in the + * documentation and/or other materials provided with the distribution. + * * Neither the name of Sony Pictures Imageworks nor the names of its + * contributors may be used to endorse or promote products derived from + * this software without specific prior written permission. + * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS + * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT + * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR + * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT + * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, + * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT + * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, + * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY + * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT + * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE + * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. + */ + +#include <OpenImageIO/fmath.h> + +#include <OSL/genclosure.h> + +#include "osl_closures.h" + +CCL_NAMESPACE_BEGIN + +using namespace OSL; + +class AshikhminVelvetClosure : public BSDFClosure { +public: + Vec3 m_N; + float m_sigma; + float m_invsigma2; + + AshikhminVelvetClosure() : BSDFClosure(Labels::DIFFUSE) { } + + void setup() + { + m_sigma = std::max(m_sigma, 0.01f); + m_invsigma2 = 1.0f/(m_sigma * m_sigma); + } + + bool mergeable (const ClosurePrimitive *other) const { + const AshikhminVelvetClosure *comp = (const AshikhminVelvetClosure *)other; + return m_N == comp->m_N && m_sigma == comp->m_sigma && + BSDFClosure::mergeable(other); + } + + size_t memsize () const { return sizeof(*this); } + + const char *name () const { return "ashikhmin_velvet"; } + + void print_on (std::ostream &out) const + { + out << name() << " ("; + out << "(" << m_N[0] << ", " << m_N[1] << ", " << m_N[2] << "), "; + out << m_sigma; + out << ")"; + } + + float albedo (const Vec3 &omega_out) const + { + return 1.0f; + } + + Color3 eval_reflect (const Vec3 &omega_out, const Vec3 &omega_in, float& pdf) const + { + float cosNO = m_N.dot(omega_out); + float cosNI = m_N.dot(omega_in); + if (cosNO > 0 && cosNI > 0) { + Vec3 H = omega_in + omega_out; + H.normalize(); + + float cosNH = m_N.dot(H); + float cosHO = fabsf(omega_out.dot(H)); + + float cosNHdivHO = cosNH / cosHO; + cosNHdivHO = std::max(cosNHdivHO, 0.00001f); + + float fac1 = 2 * fabsf(cosNHdivHO * cosNO); + float fac2 = 2 * fabsf(cosNHdivHO * cosNI); + + float sinNH2 = 1 - cosNH * cosNH; + float sinNH4 = sinNH2 * sinNH2; + float cotangent2 = (cosNH * cosNH) / sinNH2; + + float D = expf(-cotangent2 * m_invsigma2) * m_invsigma2 * float(M_1_PI) / sinNH4; + float G = std::min(1.0f, std::min(fac1, fac2)); // TODO: derive G from D analytically + + float out = 0.25f * (D * G) / cosNO; + + pdf = 0.5f * (float) M_1_PI; + return Color3 (out, out, out); + } + return Color3 (0, 0, 0); + } + + Color3 eval_transmit (const Vec3 &omega_out, const Vec3 &omega_in, float& pdf) const + { + return Color3 (0, 0, 0); + } + + 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 + { + // we are viewing the surface from above - send a ray out with uniform + // distribution over the hemisphere + sample_uniform_hemisphere (m_N, omega_out, randu, randv, omega_in, pdf); + if (Ng.dot(omega_in) > 0) { + Vec3 H = omega_in + omega_out; + H.normalize(); + + float cosNI = m_N.dot(omega_in); + float cosNO = m_N.dot(omega_out); + float cosNH = m_N.dot(H); + float cosHO = fabsf(omega_out.dot(H)); + + float cosNHdivHO = cosNH / cosHO; + cosNHdivHO = std::max(cosNHdivHO, 0.00001f); + + float fac1 = 2 * fabsf(cosNHdivHO * cosNO); + float fac2 = 2 * fabsf(cosNHdivHO * cosNI); + + float sinNH2 = 1 - cosNH * cosNH; + float sinNH4 = sinNH2 * sinNH2; + float cotangent2 = (cosNH * cosNH) / sinNH2; + + float D = expf(-cotangent2 * m_invsigma2) * m_invsigma2 * float(M_1_PI) / sinNH4; + float G = std::min(1.0f, std::min(fac1, fac2)); // TODO: derive G from D analytically + + float power = 0.25f * (D * G) / cosNO; + + eval.setValue(power, power, power); + + // TODO: find a better approximation for the retroreflective bounce + domega_in_dx = (2 * m_N.dot(domega_out_dx)) * m_N - domega_out_dx; + domega_in_dy = (2 * m_N.dot(domega_out_dy)) * m_N - domega_out_dy; + domega_in_dx *= 125; + domega_in_dy *= 125; + } else + pdf = 0; + return Labels::REFLECT; + } + +}; + + + +ClosureParam bsdf_ashikhmin_velvet_params[] = { + CLOSURE_VECTOR_PARAM(AshikhminVelvetClosure, m_N), + CLOSURE_FLOAT_PARAM (AshikhminVelvetClosure, m_sigma), + CLOSURE_STRING_KEYPARAM("label"), + CLOSURE_FINISH_PARAM(AshikhminVelvetClosure) }; + +CLOSURE_PREPARE(bsdf_ashikhmin_velvet_prepare, AshikhminVelvetClosure) + +CCL_NAMESPACE_END + |