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/*
* 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;
/// Variable cone emissive closure
///
/// This primitive emits in a cone having a configurable
/// penumbra area where the light decays to 0 reaching the
/// outer_angle limit. It can also behave as a lambertian emitter
/// if the provided angles are PI/2, which is the default
///
class GenericEmissiveClosure : public EmissiveClosure {
public:
GenericEmissiveClosure() { }
void setup() { }
size_t memsize () const { return sizeof(*this); }
const char *name () const { return "emission"; }
void print_on (std::ostream &out) const {
out << name() << "()";
}
Color3 eval (const Vec3 &Ng, const Vec3 &omega_out) const
{
float cosNO = fabsf(Ng.dot(omega_out));
float res = cosNO > 0 ? 1.0f / float(M_PI) : 0.0f;
return Color3(res, res, res);
}
void sample (const Vec3 &Ng, float randu, float randv,
Vec3 &omega_out, float &pdf) const
{
// We don't do anything sophisticated here for the step
// We just sample the whole cone uniformly to the cosine
Vec3 T, B;
make_orthonormals(Ng, T, B);
float phi = 2 * (float) M_PI * randu;
float cosTheta = sqrtf(1.0f - 1.0f * randv);
float sinTheta = sqrtf(1.0f - cosTheta * cosTheta);
omega_out = (cosf(phi) * sinTheta) * T +
(sinf(phi) * sinTheta) * B +
cosTheta * Ng;
pdf = 1.0f / float(M_PI);
}
/// Return the probability distribution function in the direction omega_out,
/// given the parameters and the light's surface normal. This MUST match
/// the PDF computed by sample().
float pdf (const Vec3 &Ng,
const Vec3 &omega_out) const
{
float cosNO = Ng.dot(omega_out);
return cosNO > 0 ? 1.0f / float(M_PI) : 0.0f;
}
};
ClosureParam closure_emission_params[] = {
CLOSURE_STRING_KEYPARAM("label"),
CLOSURE_FINISH_PARAM(GenericEmissiveClosure) };
CLOSURE_PREPARE(closure_emission_prepare, GenericEmissiveClosure)
CCL_NAMESPACE_END
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