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// Copyright 2009-2020 Intel Corporation
// SPDX-License-Identifier: Apache-2.0
#include "light.isph"
#include "../math/sampling.isph"
#include "../math/linearspace.isph"
struct AmbientLight
{
Light super; //!< inherited light fields
Vec3f radiance; //!< RGB color and intensity of light
};
// Implementation
//////////////////////////////////////////////////////////////////////////////
// XXX importance sampling is only done into the positive hemisphere
// ==> poor support for translucent materials
Light_SampleRes AmbientLight_sample(const uniform Light* uniform super,
const DifferentialGeometry& dg,
const Vec2f& s)
{
uniform AmbientLight* uniform self = (uniform AmbientLight* uniform)super;
Light_SampleRes res;
const Vec3f localDir = cosineSampleHemisphere(s);
res.dir = frame(dg.Ns) * localDir;
res.pdf = cosineSampleHemispherePDF(localDir);
res.dist = inf;
res.weight = self->radiance * rcp(res.pdf);
return res;
}
Light_EvalRes AmbientLight_eval(const uniform Light* uniform super,
const DifferentialGeometry& dg,
const Vec3f& dir)
{
uniform AmbientLight* uniform self = (uniform AmbientLight* uniform)super;
Light_EvalRes res;
res.value = self->radiance;
res.dist = inf;
res.pdf = cosineSampleHemispherePDF(max(dot(dg.Ns, dir), 0.f));
return res;
}
void AmbientLight_Constructor(uniform AmbientLight* uniform self,
const uniform Vec3f& radiance)
{
Light_Constructor(&self->super);
self->radiance = radiance;
self->super.sample = AmbientLight_sample;
self->super.eval = AmbientLight_eval;
}
// Exports (called from C++)
//////////////////////////////////////////////////////////////////////////////
//! Create an ispc-side AmbientLight object
export void *uniform AmbientLight_create()
{
uniform AmbientLight* uniform self = uniform new uniform AmbientLight;
AmbientLight_Constructor(self, make_Vec3f(1.f));
return self;
}
//! Set the parameters of an ispc-side AmbientLight object
export void AmbientLight_set(void* uniform super,
const uniform Vec3f& radiance)
{
uniform AmbientLight* uniform self = (uniform AmbientLight* uniform)super;
self->radiance = radiance;
}
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