forked from bartvdbraak/blender
139 lines
3.5 KiB
C++
139 lines
3.5 KiB
C++
/*
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* Copyright 2011, Blender Foundation.
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*
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* This program is free software; you can redistribute it and/or
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* modify it under the terms of the GNU General Public License
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* as published by the Free Software Foundation; either version 2
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* of the License, or (at your option) any later version.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program; if not, write to the Free Software Foundation,
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* Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
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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 OrenNayarClosure : public BSDFClosure {
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public:
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Vec3 m_N;
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float m_sigma;
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float m_a, m_b;
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OrenNayarClosure() : BSDFClosure(Labels::DIFFUSE) {}
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void setup() {
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m_sigma = clamp(m_sigma, 0.0f, 1.0f);
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float div = 1.0f / (M_PI + ((3.0f * M_PI - 4.0f) / 6.0f) * m_sigma);
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m_a = 1.0f * div;
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m_b = m_sigma * div;
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}
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bool mergeable(const ClosurePrimitive *other) const {
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const OrenNayarClosure *comp = static_cast<const OrenNayarClosure *>(other);
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return
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m_N == comp->m_N &&
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m_sigma == comp->m_sigma &&
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BSDFClosure::mergeable(other);
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}
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size_t memsize() const {
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return sizeof(*this);
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}
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const char *name() const {
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return "oren_nayar";
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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_sigma;
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out << ")";
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}
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float albedo(const Vec3& omega_out) const {
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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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if (m_N.dot(omega_in) > 0.0f) {
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pdf = float(0.5 * M_1_PI);
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float is = get_intensity(m_N, omega_out, omega_in);
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return Color3(is, is, is);
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}
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else {
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pdf = 0.0f;
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return Color3(0.0f, 0.0f, 0.0f);
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}
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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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return Color3(0.0f, 0.0f, 0.0f);
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}
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ustring sample(
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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
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) const {
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sample_uniform_hemisphere(m_N, omega_out, randu, randv, omega_in, pdf);
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if (Ng.dot(omega_in) > 0.0f) {
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float is = get_intensity(m_N, omega_out, omega_in);
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eval.setValue(is, is, is);
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// TODO: find a better approximation for the bounce
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domega_in_dx = (2.0f * m_N.dot(domega_out_dx)) * m_N - domega_out_dx;
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domega_in_dy = (2.0f * m_N.dot(domega_out_dy)) * m_N - domega_out_dy;
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domega_in_dx *= 125.0f;
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domega_in_dy *= 125.0f;
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}
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else {
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pdf = 0.0f;
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}
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return Labels::REFLECT;
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}
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private:
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float get_intensity(Vec3 const& n, Vec3 const& v, Vec3 const& l) const {
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float nl = max(n.dot(l), 0.0f);
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float nv = max(n.dot(v), 0.0f);
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float t = l.dot(v) - nl * nv;
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if (t > 0.0f) {
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t /= max(nl, nv) + 1e-8f;
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}
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return nl * (m_a + m_b * t);
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}
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};
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ClosureParam bsdf_oren_nayar_params[] = {
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CLOSURE_VECTOR_PARAM(OrenNayarClosure, m_N),
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CLOSURE_FLOAT_PARAM(OrenNayarClosure, m_sigma),
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CLOSURE_STRING_KEYPARAM("label"),
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CLOSURE_FINISH_PARAM(OrenNayarClosure)
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};
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CLOSURE_PREPARE(bsdf_oren_nayar_prepare, OrenNayarClosure)
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CCL_NAMESPACE_END
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