Unresolved Emitter

template<IsSpectral TSpectral>
class UnresolvedEmitter : public huira::UnresolvedObject<TSpectral>

Represents an unresolved isotropic point source with spectral power.

UnresolvedEmitter models a self-luminous object that emits light uniformly in all directions. The irradiance is computed using inverse square law based on the distance from the observer (assumed to be at the origin) and the total spectral power.

Template Parameters:

TSpectral – The spectral representation type.

Public Functions

UnresolvedEmitter(const units::SpectralWatts<TSpectral> &spectral_power)

Constructs an UnresolvedEmitter from spectral power.

Creates an emitter with the specified spectral power distribution. The spectral power is validated to ensure all components are non-negative and finite.

Parameters:

spectral_power – The spectral power in watts per wavelength bin.

Throws:

std::runtime_error – if the spectral power contains invalid values.

UnresolvedEmitter(const units::Watt &power)

Constructs an UnresolvedEmitter from total power.

Creates an emitter with a total power value that is distributed across spectral bins proportionally to their wavelength widths.

Parameters:

power – The total power in watts.

Throws:

std::runtime_error – if the power is negative, NaN, or infinite.

virtual void resolve_irradiance(const std::vector<Transform<float>> &self_transforms, const std::vector<Time> &times, const SceneView<TSpectral> &scene_view, RandomSampler<float> &sampler) override

Resolves the spectral irradiance based on distance and spectral power.

Computes the irradiance at the observer (assumed to be at the origin) using the inverse square law, at each temporal sample of the exposure. The irradiance is calculated as: \(E = \frac{\Phi}{4\pi d^2}\), where \(\Phi\) is the spectral power and \(d\) is the distance from the observer.

Parameters:

• self_transforms – Camera-relative transforms of the emitter, one per temporal sample.

• times – Absolute times of the temporal samples.

• scene_view – The scene view (unused; the emitter is self-luminous).

• sampler – Random sampler (unused; the model is analytic).

void set_spectral_power(const units::SpectralWatts<TSpectral> &spectral_power)

Sets the spectral power of the emitter.

Updates the emitter’s spectral power distribution. The values are converted to SI units and validated to ensure all components are non-negative and finite.

Parameters:

spectral_power – The new spectral power in watts per wavelength bin.

Throws:

std::runtime_error – if the spectral power contains invalid values.

void set_spectral_power(const units::Watt &power)

Sets the total power of the emitter.

Updates the emitter’s power by distributing the total value proportionally across spectral bins based on their wavelength widths. The power is validated to ensure it is non-negative and finite.

Parameters:

power – The total power in watts.

Throws:

std::runtime_error – if the power is negative, NaN, or infinite.

inline virtual std::string type() const override

Get the object’s type string.

Returns:

std::string Type

void set_irradiance(const units::SpectralWattsPerMeterSquared<TSpectral> &spectral_irradiance)

Sets the spectral irradiance of the unresolved object.

Updates the object’s irradiance value as a single constant entry. All spectral components must be non-negative, as negative irradiance is physically meaningless.

Parameters:

spectral_irradiance – The new spectral irradiance value in \(W \cdot m^{-2}\).

Throws:

std::runtime_error – if any irradiance component is negative.

void set_irradiance(const units::WattsPerMeterSquared &irradiance)

Sets the total irradiance of the unresolved object.

Updates the object’s irradiance by converting a total irradiance value (in watts per square meter) to the spectral representation, stored as a single constant entry. The total irradiance must be non-negative, as negative values are physically meaningless.

Parameters:

irradiance – The new total irradiance value in \(W \cdot m^{-2}\).

Throws:

std::runtime_error – if the total irradiance is negative, NaN, or infinite.

virtual TSpectral get_irradiance(Time time) const

Returns the spectral irradiance at a given time.

If the object holds a single (constant) irradiance entry, it is returned directly. Otherwise, the per-temporal-sample entries are linearly interpolated over the time range cached by set_resolved_irradiance_(). Times outside the range are clamped to the endpoints.

Parameters:

time – The time at which to query irradiance.

Returns:

The spectral irradiance value at the requested time.

inline bool is_scene_owned() const

Check if the object is owned by the scene.

Returns:

bool True if owned

inline void set_scene_owned(bool owned)

Set scene ownership flag.

Parameters:

owned – True if owned

inline std::string name() const

Get the object’s name.

Returns:

std::string Name

inline virtual std::uint64_t id() const

Get the object’s unique ID.

Returns:

std::uint64_t ID

inline virtual std::string get_info() const

Get a descriptive info string for the object.

Returns:

std::string Info string

Protected Functions

void set_resolved_irradiance_(std::vector<TSpectral> irradiances, const std::vector<Time> &times)

Stores resolved per-temporal-sample irradiances and their time range.

Validates the irradiance values and caches the time range endpoints used by get_irradiance() for interpolation. irradiances must either contain a single (constant) entry, or exactly one entry per entry in times.

Parameters:

• irradiances – Resolved spectral irradiances, one per temporal sample (or a single constant entry).

• times – Absolute times of the temporal samples.

Throws:

std::runtime_error – if sizes are inconsistent or any value is invalid.

Protected Attributes

std::vector<TSpectral> irradiance_ = {TSpectral{0}}

Spectral irradiance per temporal sample (size 1 == constant).

double et_start_ = {0.0}

Ephemeris-time endpoints of the resolved sample range (used for interpolation).

double et_end_ = {0.0}