void DirectLightingIntegrator::take_single_light_sample(
SamplingContext& sampling_context,
const MISHeuristic mis_heuristic,
const Dual3d& outgoing,
Spectrum& radiance,
SpectrumStack& aovs) const
{
// todo: if we had a way to know that a BSDF is purely specular, we could
// immediately return black here since there will be no contribution from
// such a BSDF.
if (!m_light_sampler.has_lights_or_emitting_triangles())
return;
const Vector3d s = sampling_context.next_vector2<3>();
LightSample sample;
m_light_sampler.sample(m_time, s, sample);
if (sample.m_triangle)
{
add_emitting_triangle_sample_contribution(
sample,
mis_heuristic,
outgoing,
radiance,
aovs);
}
else
{
add_non_physical_light_sample_contribution(
sample,
outgoing,
radiance,
aovs);
}
}
void DirectLightingIntegrator::compute_outgoing_radiance_light_sampling_low_variance(
SamplingContext& sampling_context,
const MISHeuristic mis_heuristic,
const Dual3d& outgoing,
Spectrum& radiance,
SpectrumStack& aovs) const
{
radiance.set(0.0f);
aovs.set(0.0f);
// todo: if we had a way to know that a BSDF is purely specular, we could
// immediately return black here since there will be no contribution from
// such a BSDF.
// Sample emitting triangles.
if (m_light_sampler.get_emitting_triangle_count() > 0)
{
sampling_context.split_in_place(3, m_light_sample_count);
for (size_t i = 0; i < m_light_sample_count; ++i)
{
const Vector3d s = sampling_context.next_vector2<3>();
LightSample sample;
m_light_sampler.sample_emitting_triangles(m_time, s, sample);
add_emitting_triangle_sample_contribution(
sample,
mis_heuristic,
outgoing,
radiance,
aovs);
}
if (m_light_sample_count > 1)
{
const float rcp_light_sample_count = 1.0f / m_light_sample_count;
radiance *= rcp_light_sample_count;
aovs *= rcp_light_sample_count;
}
}
// Sample non-physical light sources.
const size_t light_count = m_light_sampler.get_non_physical_light_count();
if (light_count > 0)
{
sampling_context.split_in_place(2, light_count);
for (size_t i = 0; i < light_count; ++i)
{
const Vector2d s = sampling_context.next_vector2<2>();
LightSample sample;
m_light_sampler.sample_non_physical_light(m_time, s, i, sample);
add_non_physical_light_sample_contribution(
sample,
outgoing,
radiance,
aovs);
}
}
}
void DirectLightingIntegrator::compute_outgoing_radiance_light_sampling_low_variance(
SamplingContext& sampling_context,
const MISHeuristic mis_heuristic,
const Dual3d& outgoing,
DirectShadingComponents& radiance,
LightPathStream* light_path_stream) const
{
radiance.set(0.0f);
// No light source in the scene.
if (!m_light_sampler.has_lights())
return;
// Check if PDF of the sampler is Dirac delta and therefore cannot contribute to the light sampling.
if (!m_material_sampler.contributes_to_light_sampling())
return;
if (m_light_sample_count > 0)
{
// Add contributions from all non-physical light sources that aren't part of the lightset.
for (size_t i = 0, e = m_light_sampler.get_non_physical_light_count(); i < e; ++i)
{
// Sample the light.
LightSample sample;
m_light_sampler.sample_non_physical_light(m_time, i, sample);
// Add the contribution of the chosen light.
add_non_physical_light_sample_contribution(
sampling_context,
sample,
outgoing,
radiance,
light_path_stream);
}
}
// Add contributions from the light set.
if (m_light_sampler.has_lightset())
{
DirectShadingComponents lightset_radiance;
sampling_context.split_in_place(3, m_light_sample_count);
for (size_t i = 0, e = m_light_sample_count; i < e; ++i)
{
// Sample the light set.
LightSample sample;
m_light_sampler.sample_lightset(
m_time,
sampling_context.next2<Vector3f>(),
m_material_sampler.get_shading_point(),
sample);
// Add the contribution of the chosen light.
if (sample.m_shape)
{
add_emitting_shape_sample_contribution(
sampling_context,
sample,
mis_heuristic,
outgoing,
lightset_radiance,
light_path_stream);
}
else
{
add_non_physical_light_sample_contribution(
sampling_context,
sample,
outgoing,
lightset_radiance,
light_path_stream);
}
}
if (m_light_sample_count > 1)
lightset_radiance /= static_cast<float>(m_light_sample_count);
radiance += lightset_radiance;
}
}
