FORCE_INLINE virtual double evaluate_pdf(
const void* data,
const Vector3d& geometric_normal,
const Basis3d& shading_basis,
const Vector3d& outgoing,
const Vector3d& incoming,
const int modes) const
{
if (!(modes & Glossy))
return 0.0;
// If incoming and outgoing are on the same hemisphere
// this is not a refraction.
const Vector3d& n = shading_basis.get_normal();
if (dot(incoming, n) * dot(outgoing, n) >= 0.0)
return Absorption;
const InputValues* values = static_cast<const InputValues*>(data);
double ht_norm;
const Vector3d ht = half_refraction_vector(
outgoing,
incoming,
n,
values->m_from_ior,
values->m_to_ior,
ht_norm);
const Vector3d m = shading_basis.transform_to_local(ht);
const double dwh_dwo = refraction_jacobian(
incoming,
values->m_to_ior,
ht,
ht_norm);
return m_mdf->pdf(m, values->m_ax, values->m_ay) * dwh_dwo;
}
FORCE_INLINE virtual double evaluate(
const void* data,
const bool adjoint,
const bool cosine_mult,
const Vector3d& geometric_normal,
const Basis3d& shading_basis,
const Vector3d& outgoing,
const Vector3d& incoming,
const int modes,
Spectrum& value) const
{
if (!(modes & Glossy))
return 0.0;
// If incoming and outgoing are on the same hemisphere
// this is not a refraction.
const Vector3d& n = shading_basis.get_normal();
if (dot(incoming, n) * dot(outgoing, n) >= 0.0)
return Absorption;
const InputValues* values = static_cast<const InputValues*>(data);
double ht_norm;
const Vector3d ht = half_refraction_vector(
outgoing,
incoming,
n,
values->m_from_ior,
values->m_to_ior,
ht_norm);
const Vector3d m = shading_basis.transform_to_local(ht);
const double G =
m_mdf->G(
shading_basis.transform_to_local(incoming),
shading_basis.transform_to_local(outgoing),
m,
values->m_ax,
values->m_ay);
if (G == 0.0)
return 0.0;
const double D = m_mdf->D(m, values->m_ax, values->m_ay);
const double cos_oh = dot(outgoing, ht);
const double cos_ih = dot(incoming, ht);
const double cos_in = dot(incoming, n);
const double cos_on = dot(outgoing, n);
// [1] equation 21.
double v = abs((cos_ih * cos_oh) / (cos_in * cos_on));
v *= square(values->m_to_ior) * D * G;
const double denom = values->m_to_ior * cos_ih + values->m_from_ior * cos_oh;
v /= square(denom);
value.set(static_cast<float>(v));
const double dwh_dwo = refraction_jacobian(
incoming,
values->m_to_ior,
ht,
ht_norm);
return m_mdf->pdf(m, values->m_ax, values->m_ay) * dwh_dwo;
}
FORCE_INLINE virtual Mode sample(
SamplingContext& sampling_context,
const void* data,
const bool adjoint,
const bool cosine_mult,
const Vector3d& geometric_normal,
const Basis3d& shading_basis,
const Vector3d& outgoing,
Vector3d& incoming,
Spectrum& value,
double& probability) const
{
const InputValues* values = static_cast<const InputValues*>(data);
// Compute the incoming direction by sampling the MDF.
sampling_context.split_in_place(2, 1);
const Vector2d s = sampling_context.next_vector2<2>();
const Vector3d m = m_mdf->sample(s, values->m_ax, values->m_ay);
const Vector3d ht = shading_basis.transform_to_parent(m);
if (!refract(
outgoing,
ht,
values->m_from_ior / values->m_to_ior,
incoming))
{
// Ignore TIR.
return Absorption;
}
// If incoming and outgoing are on the same hemisphere
// this is not a refraction.
const Vector3d& n = shading_basis.get_normal();
if (dot(incoming, n) * dot(outgoing, n) >= 0.0)
return Absorption;
const double G =
m_mdf->G(
shading_basis.transform_to_local(incoming),
shading_basis.transform_to_local(outgoing),
m,
values->m_ax,
values->m_ay);
if (G == 0.0)
return Absorption;
const double D = m_mdf->D(m, values->m_ax, values->m_ay);
const double cos_oh = dot(outgoing, ht);
const double cos_ih = dot(incoming, ht);
const double cos_in = dot(incoming, n);
const double cos_on = dot(outgoing, n);
// [1] equation 21.
double v = abs((cos_ih * cos_oh) / (cos_in * cos_on));
v *= square(values->m_to_ior) * D * G;
const double denom = values->m_to_ior * cos_ih + values->m_from_ior * cos_oh;
v /= square(denom);
value.set(static_cast<float>(v));
const double ht_norm = norm(values->m_from_ior * outgoing + values->m_to_ior * incoming);
const double dwh_dwo = refraction_jacobian(
incoming,
values->m_to_ior,
ht,
ht_norm);
probability = m_mdf->pdf(m, values->m_ax, values->m_ay) * dwh_dwo;
return Glossy;
}
