Discrete spectral power distribution based on a number of wavelength bins over the 360-830 nm range. More...

#include <mitsuba/core/spectrum.h>

Inheritance diagram for mitsuba::Spectrum:

Public Types
enum	EConversionIntent { EReflectance, EIlluminant }
	When converting from RGB reflectance values to discretized color spectra, the following `intent' flag can be provided to improve the results of this highly under-constrained problem. More...

typedef TSpectrum< Float, SPECTRUM_SAMPLES >	Parent

Public Types inherited from mitsuba::TSpectrum< Float, SPECTRUM_SAMPLES >
typedef Float	Scalar

Public Member Functions
	Spectrum ()
	Create a new spectral power distribution, but don't initialize the contents. More...

	Spectrum (const Parent &s)
	Construct from a TSpectrum instance. More...

template<typename AltScalar >
	Spectrum (const TSpectrum< AltScalar, SPECTRUM_SAMPLES > &v)
	Initialize with a TSpectrum data type based on a alternate representation. More...

	Spectrum (Float v)
	Create a new spectral power distribution with all samples set to the given value. More...

	Spectrum (Float value[SPECTRUM_SAMPLES])
	Copy a spectral power distribution. More...

	Spectrum (Stream *stream)
	Unserialize a spectral power distribution from a binary data stream. More...

Float	eval (Float lambda) const
	Evaluate the SPD for the given wavelength in nanometers. More...

Float	getLuminance () const
	Return the luminance in candelas. More...

void	toXYZ (Float &x, Float &y, Float &z) const
	Convert from a spectral power distribution to XYZ tristimulus values. More...

void	fromXYZ (Float x, Float y, Float z, EConversionIntent intent=EReflectance)
	Convert XYZ tristimulus into a plausible spectral reflectance or spectral power distribution. More...

void	toIPT (Float &I, Float &P, Float &T) const
	Convert from a spectral power distribution to the perceptually uniform IPT color space by Ebner and Fairchild. More...

void	fromIPT (Float I, Float P, Float T, EConversionIntent intent=EReflectance)
	Convert a color value represented in the IPT space into a plausible spectral reflectance or spectral power distribution. More...

void	toLinearRGB (Float &r, Float &g, Float &b) const
	Convert to linear RGB. More...

void	fromLinearRGB (Float r, Float g, Float b, EConversionIntent intent=EReflectance)
	Convert linear RGB colors into a plausible spectral power distribution. More...

void	toSRGB (Float &r, Float &g, Float &b) const
	Convert to sRGB. More...

void	fromSRGB (Float r, Float g, Float b)
	Convert sRGB color values into a plausible spectral power distribution. More...

void	fromRGBE (const uint8_t rgbe[4], EConversionIntent intent=EIlluminant)
	Convert linear RGBE colors into a plausible spectral power distribution. More...

void	toRGBE (uint8_t rgbe[4]) const
	Linear RGBE conversion based on Bruce Walter's and Greg Ward's code. More...

void	fromContinuousSpectrum (const ContinuousSpectrum &smooth)
	Initialize with spectral values from a smooth spectrum representation. More...

bool	operator== (const Spectrum &val) const
	Equality test. More...

bool	operator!= (const Spectrum &val) const
	Inequality test. More...

std::string	toString () const
	Return a string representation. More...

Public Member Functions inherited from mitsuba::TSpectrum< Float, SPECTRUM_SAMPLES >
	TSpectrum ()
	Create a new spectral power distribution, but don't initialize the contents. More...

	TSpectrum (Scalar v)
	Create a new spectral power distribution with all samples set to the given value. More...

	TSpectrum (Scalar spec[N])
	Copy a spectral power distribution. More...

	TSpectrum (Stream *stream)
	Unserialize a spectral power distribution from a binary data stream. More...

	TSpectrum (const TSpectrum< AltScalar, N > &v)
	Initialize with a TSpectrum data type based on a alternate representation. More...

TSpectrum	operator+ (const TSpectrum &spec) const
	Add two spectral power distributions. More...

TSpectrum &	operator+= (const TSpectrum &spec)
	Add a spectral power distribution to this instance. More...

TSpectrum	operator- (const TSpectrum &spec) const
	Subtract a spectral power distribution. More...

TSpectrum	operator- () const
	Negate. More...

TSpectrum &	operator-= (const TSpectrum &spec)
	Subtract a spectral power distribution from this instance. More...

TSpectrum	operator* (Scalar f) const
	Multiply by a scalar. More...

TSpectrum	operator* (const TSpectrum &spec) const
	Perform a component-wise multiplication by another spectrum. More...

TSpectrum &	operator*= (Scalar f)
	Multiply by a scalar. More...

TSpectrum &	operator*= (const TSpectrum &spec)
	Perform a component-wise multiplication by another spectrum. More...

TSpectrum &	operator/= (const TSpectrum &spec)
	Perform a component-wise division by another spectrum. More...

TSpectrum &	operator/= (Scalar f)
	Divide by a scalar. More...

TSpectrum	operator/ (const TSpectrum &spec) const
	Perform a component-wise division by another spectrum. More...

TSpectrum	operator/ (Scalar f) const
	Divide by a scalar. More...

bool	operator== (const TSpectrum &spec) const
	Equality test. More...

bool	operator!= (const TSpectrum &spec) const
	Inequality test. More...

bool	isNaN () const
	Check for NaNs. More...

bool	isValid () const
	Returns whether the spectrum only contains valid (non-NaN, nonnegative) samples. More...

void	addWeighted (Scalar weight, const TSpectrum &spec)
	Multiply-accumulate operation, adds weight * spec. More...

Scalar	average () const
	Return the average over all wavelengths. More...

TSpectrum	abs () const
	Component-wise absolute value. More...

TSpectrum	sqrt () const
	Component-wise square root. More...

TSpectrum	safe_sqrt () const
	Component-wise square root. More...

TSpectrum	log () const
	Component-wise logarithm. More...

TSpectrum	exp () const
	Component-wise exponentation. More...

TSpectrum	pow (Scalar f) const
	Component-wise power. More...

void	clampNegative ()
	Clamp negative values. More...

Scalar	max () const
	Return the highest-valued spectral sample. More...

Scalar	min () const
	Return the lowest-valued spectral sample. More...

Scalar &	operator[] (int entry)
	Indexing operator. More...

Scalar	operator[] (int entry) const
	Indexing operator. More...

bool	isZero () const
	Check if this spectrum is zero at all wavelengths. More...

void	serialize (Stream *stream) const
	Serialize this spectrum to a stream. More...

std::string	toString () const

Static Public Member Functions
static std::pair< Float, Float >	getBinCoverage (size_t index)
	Return the wavelength range covered by a spectral bin. More...

static const Spectrum &	getD65 ()
	Return a spectral color distribution of the D65 white point (with unit luminance) More...

static void	staticInitialization ()
	Static initialization (should be called once during the application's initialization phase) More...

static void	staticShutdown ()

Static Protected Attributes
static Float	m_wavelengths [SPECTRUM_SAMPLES+1]
	Configured wavelengths bins in nanometers. More...

static Spectrum	CIE_D65
	Pre-integrated D65 illuminant. More...

Pre-integrated CIE 1931 XYZ color matching functions.
static Spectrum	CIE_X

static Spectrum	CIE_Y

static Spectrum	CIE_Z

static Float	CIE_normalization

Pre-integrated Smits-style RGB to Spectrum
conversion spectra, data by Karl vom Berge
static Spectrum	rgbRefl2SpecWhite

static Spectrum	rgbRefl2SpecCyan

static Spectrum	rgbRefl2SpecMagenta

static Spectrum	rgbRefl2SpecYellow

static Spectrum	rgbRefl2SpecRed

static Spectrum	rgbRefl2SpecGreen

static Spectrum	rgbRefl2SpecBlue

static Spectrum	rgbIllum2SpecWhite

static Spectrum	rgbIllum2SpecCyan

static Spectrum	rgbIllum2SpecMagenta

static Spectrum	rgbIllum2SpecYellow

static Spectrum	rgbIllum2SpecRed

static Spectrum	rgbIllum2SpecGreen

static Spectrum	rgbIllum2SpecBlue

Additional Inherited Members
Static Public Attributes inherited from mitsuba::TSpectrum< Float, SPECTRUM_SAMPLES >
static const int	dim
	Number of dimensions. More...

Protected Attributes inherited from mitsuba::TSpectrum< Float, SPECTRUM_SAMPLES >
Scalar	s [N]

Detailed Description

Discrete spectral power distribution based on a number of wavelength bins over the 360-830 nm range.

This class defines a vector-like data type that can be used for computations involving radiance.

When configured for spectral rendering (i.e. when the compile-time flag SPECTRUM_SAMPLES is set to a value != 3), the implementation discretizes the visible spectrum of light into a set of intervals, where the distribution within each bin is modeled as being uniform.

When SPECTRUM_SAMPLES == 3, the class reverts to a simple linear RGB-based internal representation.

The implementation of this class is based on PBRT.

Member Typedef Documentation

typedef TSpectrum<Float, SPECTRUM_SAMPLES> mitsuba::Spectrum::Parent

Member Enumeration Documentation

enum mitsuba::Spectrum::EConversionIntent

When converting from RGB reflectance values to discretized color spectra, the following `intent' flag can be provided to improve the results of this highly under-constrained problem.

Enumerator
EReflectance	Unitless reflectance data is converted.
EIlluminant	Radiance-valued illumination data is converted.

Constructor & Destructor Documentation

mitsuba::Spectrum::Spectrum ( )

inline

Create a new spectral power distribution, but don't initialize the contents.

mitsuba::Spectrum::Spectrum ( const Parent & s )

inline

Construct from a TSpectrum instance.

template<typename AltScalar >

mitsuba::Spectrum::Spectrum ( const TSpectrum< AltScalar, SPECTRUM_SAMPLES > & v )

inlineexplicit

Initialize with a TSpectrum data type based on a alternate representation.

mitsuba::Spectrum::Spectrum ( Float v )

inlineexplicit

Create a new spectral power distribution with all samples set to the given value.

mitsuba::Spectrum::Spectrum ( Float value[SPECTRUM_SAMPLES] )

inlineexplicit

Copy a spectral power distribution.

mitsuba::Spectrum::Spectrum ( Stream * stream )

inlineexplicit

Unserialize a spectral power distribution from a binary data stream.

Member Function Documentation

Float mitsuba::Spectrum::eval ( Float lambda ) const

Evaluate the SPD for the given wavelength in nanometers.

void mitsuba::Spectrum::fromContinuousSpectrum ( const ContinuousSpectrum & smooth )

Initialize with spectral values from a smooth spectrum representation.

void mitsuba::Spectrum::fromIPT	(	Float	I,
		Float	P,
		Float	T,
		EConversionIntent	intent = `EReflectance`
	)

Convert a color value represented in the IPT space into a plausible spectral reflectance or spectral power distribution.

The EConversionIntent parameter can be used to provide more information on how to solve this highly under-constrained problem. The default is EReflectance.

void mitsuba::Spectrum::fromLinearRGB	(	Float	r,
		Float	g,
		Float	b,
		EConversionIntent	intent = `EReflectance`
	)

Convert linear RGB colors into a plausible spectral power distribution.

The EConversionIntent parameter can be used to provide more information on how to solve this highly under-constrained problem. The default is EReflectance.

void mitsuba::Spectrum::fromRGBE	(	const uint8_t	rgbe[4],
		EConversionIntent	intent = `EIlluminant`
	)

Convert linear RGBE colors into a plausible spectral power distribution.

Based on code by Bruce Walter and Greg ward.

The EConversionIntent parameter can be used to provide more information on how to solve this highly under-constrained problem. For RGBE values, the default is EIlluminant.

void mitsuba::Spectrum::fromSRGB	(	Float	r,
		Float	g,
		Float	b
	)

Convert sRGB color values into a plausible spectral power distribution.

Note that compared to fromLinearRGB, no intent parameter is available. For sRGB colors, it is assumed that the intent is always EReflectance.

void mitsuba::Spectrum::fromXYZ	(	Float	x,
		Float	y,
		Float	z,
		EConversionIntent	intent = `EReflectance`
	)

Convert XYZ tristimulus into a plausible spectral reflectance or spectral power distribution.

The EConversionIntent parameter can be used to provide more information on how to solve this highly under-constrained problem. The default is EReflectance.

static std::pair<Float, Float> mitsuba::Spectrum::getBinCoverage ( size_t index )

static

Return the wavelength range covered by a spectral bin.

static const Spectrum& mitsuba::Spectrum::getD65 ( )

inlinestatic

Return a spectral color distribution of the D65 white point (with unit luminance)

Float mitsuba::Spectrum::getLuminance ( ) const

Return the luminance in candelas.

bool mitsuba::Spectrum::operator!= ( const Spectrum & val ) const

inline

Inequality test.

bool mitsuba::Spectrum::operator== ( const Spectrum & val ) const

inline

Equality test.

static void mitsuba::Spectrum::staticInitialization ( )

static

Static initialization (should be called once during the application's initialization phase)

This function is responsible for choosing the wavelengths that will be used during rendering. It also pre-integrates the CIE matching curves so that sampled spectra can efficiently be converted to XYZ tristimulus values. Finally, it sets up pre-integrated color spectra for conversions from linear RGB to plausible spectral color distributions.

static void mitsuba::Spectrum::staticShutdown ( )

static

void mitsuba::Spectrum::toIPT	(	Float &	I,
		Float &	P,
		Float &	T
	)		const

Convert from a spectral power distribution to the perceptually uniform IPT color space by Ebner and Fairchild.

This is useful e.g. for computing color differences. I encodes intensity, P (protan) roughly encodes red-green color opponency, and T (tritan) encodes blue-red color opponency. For normalized input, the range of attainable values is given by $ I\in $[0,1], P,T\in [-1,1]$.

In the Python API, this function returns a 3-tuple with the result of the operation.

void mitsuba::Spectrum::toLinearRGB	(	Float &	r,
		Float &	g,
		Float &	b
	)		const

Convert to linear RGB.

In the Python API, this function returns a 3-tuple with the result of the operation.

void mitsuba::Spectrum::toRGBE ( uint8_t rgbe[4] ) const

Linear RGBE conversion based on Bruce Walter's and Greg Ward's code.

void mitsuba::Spectrum::toSRGB	(	Float &	r,
		Float &	g,
		Float &	b
	)		const

Convert to sRGB.

In the Python API, this function returns a 3-tuple with the result of the operation.

std::string mitsuba::Spectrum::toString ( ) const

Return a string representation.

void mitsuba::Spectrum::toXYZ	(	Float &	x,
		Float &	y,
		Float &	z
	)		const

Convert from a spectral power distribution to XYZ tristimulus values.

In the Python API, this function returns a 3-tuple with the result of the operation.

Member Data Documentation

Spectrum mitsuba::Spectrum::CIE_D65

staticprotected

Pre-integrated D65 illuminant.

Float mitsuba::Spectrum::CIE_normalization

staticprotected

Spectrum mitsuba::Spectrum::CIE_X

staticprotected

Spectrum mitsuba::Spectrum::CIE_Y

staticprotected

Spectrum mitsuba::Spectrum::CIE_Z

staticprotected

Float mitsuba::Spectrum::m_wavelengths[SPECTRUM_SAMPLES+1]

staticprotected

Configured wavelengths bins in nanometers.

Spectrum mitsuba::Spectrum::rgbIllum2SpecBlue

staticprotected

Spectrum mitsuba::Spectrum::rgbIllum2SpecCyan

staticprotected

Spectrum mitsuba::Spectrum::rgbIllum2SpecGreen

staticprotected

Spectrum mitsuba::Spectrum::rgbIllum2SpecMagenta

staticprotected

Spectrum mitsuba::Spectrum::rgbIllum2SpecRed

staticprotected

Spectrum mitsuba::Spectrum::rgbIllum2SpecWhite

staticprotected

Spectrum mitsuba::Spectrum::rgbIllum2SpecYellow

staticprotected

Spectrum mitsuba::Spectrum::rgbRefl2SpecBlue

staticprotected

Spectrum mitsuba::Spectrum::rgbRefl2SpecCyan

staticprotected

Spectrum mitsuba::Spectrum::rgbRefl2SpecGreen

staticprotected

Spectrum mitsuba::Spectrum::rgbRefl2SpecMagenta

staticprotected

Spectrum mitsuba::Spectrum::rgbRefl2SpecRed

staticprotected

Spectrum mitsuba::Spectrum::rgbRefl2SpecWhite

staticprotected

Spectrum mitsuba::Spectrum::rgbRefl2SpecYellow

staticprotected

The documentation for this struct was generated from the following file:

include/mitsuba/core/spectrum.h

Public Types

Public Member Functions

Static Public Member Functions

Static Protected Attributes

Additional Inherited Members

Detailed Description

Member Typedef Documentation

Member Enumeration Documentation

Constructor & Destructor Documentation

Member Function Documentation

Member Data Documentation