The Low et al. Microfacet BRDF model. More...

#include <lowmicrofacet.h>

Inherits microfacet< NDF, MaskingShadowing, Fresnel, NormalizationFactor, NAME >.

Public Member Functions
	BBM_IMPORT_CONFIG (CONF)

Spectrum	eval (const Vec3d &in, const Vec3d &out, BsdfFlag component=bsdf_flag::All, unit_t unit=unit_t::Radiance, Mask mask=true) const
	Evaluate the A*baseeval.

Spectrum	reflectance (const Vec3d &out, BsdfFlag component=bsdf_flag::All, unit_t unit=unit_t::Radiance, Mask mask=true) const
	Return albedo*basereflectance.

	BBM_DEFAULT_CONSTRUCTOR (lowmicrofacet)
	Default constructor.

BsdfSample	sample (const Vec3d &out, const Vec2d &xi, BsdfFlag component=bsdf_flag::All, unit_t unit=unit_t::Radiance, Mask mask=true) const
	Sample the microfacet BSDF given a direction and two random variables.

Value	pdf (const Vec3d &in, const Vec3d &out, BsdfFlag component=bsdf_flag::All, unit_t=unit_t::Radiance, Mask mask=true) const
	Compute the pdf given an in and out direction.

Public Member Functions inherited from microfacet< NDF, MaskingShadowing, Fresnel, NormalizationFactor, NAME >
	BBM_IMPORT_CONFIG (NDF)

Spectrum	eval (const Vec3d &in, const Vec3d &out, BsdfFlag component=bsdf_flag::All, unit_t=unit_t::Radiance, Mask mask=true) const
	Evaluate the BSDF for a given in-out direction pair.

BsdfSample	sample (const Vec3d &out, const Vec2d &xi, BsdfFlag component=bsdf_flag::All, unit_t unit=unit_t::Radiance, Mask mask=true) const
	Sample the microfacet BSDF given a direction and two random variables.

Value	pdf (const Vec3d &in, const Vec3d &out, BsdfFlag component=bsdf_flag::All, unit_t=unit_t::Radiance, Mask mask=true) const
	Compute the pdf given an in and out direction.

Spectrum	reflectance (const Vec3d &out, BsdfFlag component=bsdf_flag::All, unit_t=unit_t::Radiance, Mask mask=true) const
	Return the (approximate) hemispherical reflectance of the BSDF.

	BBM_DEFAULT_CONSTRUCTOR (microfacet)
	Default constructor.

	BBM_ATTRIBUTES (reflection::attributes(ndf), eta)

Static Public Attributes
static constexpr string_literal	name = NAME

Static Public Attributes inherited from microfacet< NDF, MaskingShadowing, Fresnel, NormalizationFactor, NAME >
static constexpr string_literal	name = NAME

Private Types
using	base = microfacet< ndf::low< CONF >, maskingshadowing::vgroove< CONF >, fresnel::cook< CONF >, NormalizationFactor, NAME >

Private Member Functions
	BBM_BASETYPES (base)

bsdf_parameter< Spectrum, bsdf_attr::SpecularParameter >	A
	Class Attributes.

	BBM_ATTRIBUTES (A)

Additional Inherited Members
Public Attributes inherited from microfacet< NDF, MaskingShadowing, Fresnel, NormalizationFactor, NAME >
	BBM_BSDF_FORWARD

NDF	ndf

fresnel_parameter< typename std::decay_t< Fresnel >::parameter_type >	eta

Detailed Description

template<typename CONF, auto NormalizationFactor = microfacet_n::Cook, string_literal NAME = "LowMicrofacet">
requires concepts::config<CONF>
class bbm::lowmicrofacet< CONF, NormalizationFactor, NAME >

The Low et al. Microfacet BRDF model.

Template Parameters

CONF	= bbm configuration
NormalizationFactor	= see below (Default: normalization_v::Cook)
NAME=	model name (default = LowMicrofacet)

The Low et al. Microfacet BSDF model is a specialization microfacet that uses an unnormalized scale 'A'.

Both Low et al's supplemental document as well as the paper (Eq. 15) do not list any normalization factor, which makes sense since 'A' is not normalized. This is the default behavior of this implementation. However, the MERL-MIT BRDF fits listed in Low et al.'s supplemental document includes an additional (incorrect) normalization factor of 'Pi'

Implements: concepts::bsdfmodel

Member Typedef Documentation

◆ base

using base = microfacet<ndf::low<CONF>, maskingshadowing::vgroove<CONF>, fresnel::cook<CONF>, NormalizationFactor, NAME>

private

Member Function Documentation

◆ BBM_ATTRIBUTES()

BBM_ATTRIBUTES ( A )

◆ BBM_BASETYPES()

BBM_BASETYPES ( base )

private

◆ BBM_DEFAULT_CONSTRUCTOR()

BBM_DEFAULT_CONSTRUCTOR ( lowmicrofacet< CONF, NormalizationFactor, NAME > )

inline

Default constructor.

◆ BBM_IMPORT_CONFIG()

BBM_IMPORT_CONFIG ( CONF )

◆ eval()

Spectrum eval	(	const Vec3d &	in,
		const Vec3d &	out,
		BsdfFlag	component = `bsdf_flag::All`,
		unit_t	unit = `unit_t::Radiance`,
		Mask	mask = `true`
	)		const

inline

Evaluate the A*baseeval.

Parameters

in	= incident direction
out	= outgoing direction
component	= which reflectance component to eval
unit	= unit of computation (ignored)
mask	= masking of lanes (e.g., for Packet eval)

Returns: Evaluation of the BSDF per spectrum.

◆ pdf()

Value pdf	(	const Vec3d &	in,
		const Vec3d &	out,
		BsdfFlag	component = `bsdf_flag::All`,
		unit_t	= `unit_t::Radiance`,
		Mask	mask = `true`
	)		const

inline

Compute the pdf given an in and out direction.

Parameters

in	= the incoming (sampled) direction
out	= the outgoing (given) direction
component	= which reflectance component was sampled
unit	= unit of computation (ignored)
mask	= masking of lanes

Returns: the PDF that the incoming direction would be sampled given the outgoing direction.

◆ reflectance()

Spectrum reflectance	(	const Vec3d &	out,
		BsdfFlag	component = `bsdf_flag::All`,
		unit_t	unit = `unit_t::Radiance`,
		Mask	mask = `true`
	)		const

inline

Return albedo*basereflectance.

Parameters

out	= the outgoing direction
component	= which reflectance component to eval
unit	= unit of computation (ignored)
mask	= masking of lanes

Returns: the approximate hemispherical reflectance of the BSDF for a given direction

◆ sample()

BsdfSample sample	(	const Vec3d &	out,
		const Vec2d &	xi,
		BsdfFlag	component = `bsdf_flag::All`,
		unit_t	unit = `unit_t::Radiance`,
		Mask	mask = `true`
	)		const

inline

Sample the microfacet BSDF given a direction and two random variables.

Parameters

out	= outgoing direction
xi	= two random variables stored in a Vec2d
component	= which reflectance component to sample
unit	= unit of computation (ignored)
mask	= masking of lanes.

Returns: A bsdfSample containing the sampled direction and the corresponding pdf.

Member Data Documentation

◆ A

bsdf_parameter<Spectrum, bsdf_attr::SpecularParameter> A

Class Attributes.

◆ name

constexpr string_literal name = NAME

staticconstexpr

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

include/bsdfmodel/lowmicrofacet.h

Public Member Functions

Static Public Attributes

Private Types

Private Member Functions

Additional Inherited Members

Detailed Description

Member Typedef Documentation

◆ base

Member Function Documentation

◆ BBM_ATTRIBUTES()

◆ BBM_BASETYPES()

◆ BBM_DEFAULT_CONSTRUCTOR()

◆ BBM_IMPORT_CONFIG()

◆ eval()

◆ pdf()

◆ reflectance()

◆ sample()

Member Data Documentation

◆ A

◆ name