void compute_radiance(
InputEvaluator& input_evaluator,
const Transformd& light_transform,
const Vector3d& axis,
const Vector3d& outgoing,
Spectrum& radiance) const
{
const Vector3d up = light_transform.vector_to_parent(m_up);
const Vector3d v = -axis;
const Vector3d u = normalize(cross(up, v));
const Vector3d n = cross(v, u);
const double cos_theta = dot(outgoing, axis);
assert(cos_theta > m_cos_outer_half_angle);
const Vector3d d = outgoing / cos_theta - axis;
const float x = static_cast<float>(dot(d, u) * m_rcp_screen_half_size);
const float y = static_cast<float>(dot(d, n) * m_rcp_screen_half_size);
const Vector2f uv(0.5f * (x + 1.0f), 0.5f * (y + 1.0f));
const InputValues* values = input_evaluator.evaluate<InputValues>(m_inputs, uv);
radiance = values->m_intensity;
radiance *= static_cast<float>(values->m_intensity_multiplier);
if (cos_theta < m_cos_inner_half_angle)
{
radiance *=
static_cast<float>(
smoothstep(m_cos_outer_half_angle, m_cos_inner_half_angle, cos_theta));
}
}
double get_autofocus_focal_distance(const Intersector& intersector) const
{
// The autofocus considers the scene at the middle of the shutter interval.
const float time = get_shutter_middle_time();
const Transformd transform = m_transform_sequence.evaluate(time);
// Create a ray that goes through the center of the lens.
ShadingRay ray;
ray.m_org = transform.get_local_to_parent().extract_translation();
ray.m_dir = normalize(transform.vector_to_parent(-ndc_to_camera(m_autofocus_target)));
ray.m_tmin = 0.0;
ray.m_tmax = numeric_limits<double>::max();
ray.m_time =
ShadingRay::Time::create_with_normalized_time(
0.5f,
get_shutter_open_time(),
get_shutter_close_time());
ray.m_flags = VisibilityFlags::ProbeRay;
ray.m_depth = 0;
// Trace the ray.
ShadingPoint shading_point;
intersector.trace(ray, shading_point);
if (shading_point.hit())
{
// Hit: compute the focal distance.
const Vector3d v = shading_point.get_point() - ray.m_org;
const double af_focal_distance = -transform.vector_to_local(v).z;
RENDERER_LOG_INFO(
"camera \"%s\": autofocus sets focal distance to %f (using camera position at time=%.1f).",
get_path().c_str(),
af_focal_distance,
ray.m_time.m_absolute);
return af_focal_distance;
}
else
{
// Miss: focus at infinity.
RENDERER_LOG_INFO(
"camera \"%s\": autofocus sets focal distance to infinity (using camera position at time=%.1f).",
get_path().c_str(),
ray.m_time.m_absolute);
return 1.0e38;
}
}