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UsdLuxShapingAPI Class Reference

#include <shapingAPI.h>

+ Inheritance diagram for UsdLuxShapingAPI:

Public Member Functions

 UsdLuxShapingAPI (const UsdPrim &prim=UsdPrim())
 
 UsdLuxShapingAPI (const UsdSchemaBase &schemaObj)
 
virtual USDLUX_API ~UsdLuxShapingAPI ()
 Destructor. More...
 
USDLUX_API UsdAttribute GetShapingFocusAttr () const
 
USDLUX_API UsdAttribute CreateShapingFocusAttr (VtValue const &defaultValue=VtValue(), bool writeSparsely=false) const
 
USDLUX_API UsdAttribute GetShapingFocusTintAttr () const
 
USDLUX_API UsdAttribute CreateShapingFocusTintAttr (VtValue const &defaultValue=VtValue(), bool writeSparsely=false) const
 
USDLUX_API UsdAttribute GetShapingConeAngleAttr () const
 
USDLUX_API UsdAttribute CreateShapingConeAngleAttr (VtValue const &defaultValue=VtValue(), bool writeSparsely=false) const
 
USDLUX_API UsdAttribute GetShapingConeSoftnessAttr () const
 
USDLUX_API UsdAttribute CreateShapingConeSoftnessAttr (VtValue const &defaultValue=VtValue(), bool writeSparsely=false) const
 
USDLUX_API UsdAttribute GetShapingIesFileAttr () const
 
USDLUX_API UsdAttribute CreateShapingIesFileAttr (VtValue const &defaultValue=VtValue(), bool writeSparsely=false) const
 
USDLUX_API UsdAttribute GetShapingIesAngleScaleAttr () const
 
USDLUX_API UsdAttribute CreateShapingIesAngleScaleAttr (VtValue const &defaultValue=VtValue(), bool writeSparsely=false) const
 
USDLUX_API UsdAttribute GetShapingIesNormalizeAttr () const
 
USDLUX_API UsdAttribute CreateShapingIesNormalizeAttr (VtValue const &defaultValue=VtValue(), bool writeSparsely=false) const
 
Conversion to and from UsdShadeConnectableAPI
USDLUX_API UsdLuxShapingAPI (const UsdShadeConnectableAPI &connectable)
 
USDLUX_API UsdShadeConnectableAPI ConnectableAPI () const
 
Outputs API

Outputs represent a typed attribute on a shaping API whose value is computed externally.

USDLUX_API UsdShadeOutput CreateOutput (const TfToken &name, const SdfValueTypeName &typeName)
 
USDLUX_API UsdShadeOutput GetOutput (const TfToken &name) const
 
USDLUX_API std::vector
< UsdShadeOutput > 		GetOutputs (bool onlyAuthored=true) const
 
Inputs API

Inputs are connectable attribute with a typed value.

Shaping API parameters are encoded as inputs.

USDLUX_API UsdShadeInput CreateInput (const TfToken &name, const SdfValueTypeName &typeName)
 
USDLUX_API UsdShadeInput GetInput (const TfToken &name) const
 
USDLUX_API std::vector
< UsdShadeInput > 		GetInputs (bool onlyAuthored=true) const
 
- Public Member Functions inherited from UsdAPISchemaBase
 UsdAPISchemaBase (const UsdPrim &prim=UsdPrim())
 
 UsdAPISchemaBase (const UsdSchemaBase &schemaObj)
 
virtual USD_API ~UsdAPISchemaBase ()=0
 Destructor. More...
 
- Public Member Functions inherited from UsdSchemaBase
bool IsConcrete () const
 
bool IsTyped () const
 
bool IsAPISchema () const
 Returns whether this is an API schema or not. More...
 
bool IsAppliedAPISchema () const
 
bool IsMultipleApplyAPISchema () const
 
UsdSchemaKind GetSchemaKind () const
 Returns the kind of schema this class is. More...
 
USD_API UsdSchemaBase (const UsdPrim &prim=UsdPrim())
 Construct and store prim as the held prim. More...
 
USD_API UsdSchemaBase (const UsdSchemaBase &otherSchema)
 Construct and store for the same prim held by otherSchema. More...
 
virtual USD_API ~UsdSchemaBase ()
 Destructor. More...
 
USD_API operator bool () const
 
UsdPrim GetPrim () const
 Return this schema object's held prim. More...
 
SdfPath GetPath () const
 Shorthand for GetPrim()->GetPath(). More...
 
USD_API const UsdPrimDefinition * GetSchemaClassPrimDefinition () const
 

Static Public Member Functions

static USDLUX_API const
TfTokenVector & 		GetSchemaAttributeNames (bool includeInherited=true)
 
static USDLUX_API UsdLuxShapingAPI Get (const UsdStagePtr &stage, const SdfPath &path)
 
static USDLUX_API bool CanApply (const UsdPrim &prim, std::string *whyNot=nullptr)
 
static USDLUX_API UsdLuxShapingAPI Apply (const UsdPrim &prim)
 
- Static Public Member Functions inherited from UsdAPISchemaBase
static USD_API const
TfTokenVector & 		GetSchemaAttributeNames (bool includeInherited=true)
 
- Static Public Member Functions inherited from UsdSchemaBase
static const TfTokenVector & GetSchemaAttributeNames (bool includeInherited=true)
 

Static Public Attributes

static const UsdSchemaKind schemaKind = UsdSchemaKind::SingleApplyAPI
 
- Static Public Attributes inherited from UsdAPISchemaBase
static const UsdSchemaKind schemaKind = UsdSchemaKind::AbstractBase
 
- Static Public Attributes inherited from UsdSchemaBase
static const UsdSchemaKind schemaKind = UsdSchemaKind::AbstractBase
 

Protected Member Functions

USDLUX_API UsdSchemaKind _GetSchemaKind () const override
 
- Protected Member Functions inherited from UsdAPISchemaBase
 UsdAPISchemaBase (const UsdPrim &prim, const TfToken &instanceName)
 
 UsdAPISchemaBase (const UsdSchemaBase &schemaObj, const TfToken &instanceName)
 
const TfToken & _GetInstanceName () const
 
USD_API bool _IsCompatible () const override
 
- Protected Member Functions inherited from UsdSchemaBase
virtual UsdSchemaKind _GetSchemaType () const
 
const TfType & _GetType () const
 
USD_API UsdAttribute _CreateAttr (TfToken const &attrName, SdfValueTypeName const &typeName, bool custom, SdfVariability variability, VtValue const &defaultValue, bool writeSparsely) const
 

Friends

class UsdSchemaRegistry
 

Additional Inherited Members

- Static Protected Member Functions inherited from UsdAPISchemaBase
static USD_API TfTokenVector _GetMultipleApplyInstanceNames (const UsdPrim &prim, const TfType &schemaType)
 

Detailed Description

Controls for shaping a light's emission.

Definition at line 43 of file shapingAPI.h.

Constructor & Destructor Documentation

UsdLuxShapingAPI::UsdLuxShapingAPI ( const UsdPrim &  prim = UsdPrim())
inlineexplicit

Construct a UsdLuxShapingAPI on UsdPrim prim . Equivalent to UsdLuxShapingAPI::Get(prim.GetStage(), prim.GetPath()) for a valid prim, but will not immediately throw an error for an invalid prim

Definition at line 55 of file shapingAPI.h.

UsdLuxShapingAPI::UsdLuxShapingAPI ( const UsdSchemaBase &  schemaObj)
inlineexplicit

Construct a UsdLuxShapingAPI on the prim held by schemaObj . Should be preferred over UsdLuxShapingAPI(schemaObj.GetPrim()), as it preserves SchemaBase state.

Definition at line 63 of file shapingAPI.h.

virtual USDLUX_API UsdLuxShapingAPI::~UsdLuxShapingAPI ( )
virtual

Destructor.

USDLUX_API UsdLuxShapingAPI::UsdLuxShapingAPI ( const UsdShadeConnectableAPI &  connectable)

Constructor that takes a ConnectableAPI object. Allow implicit conversion of UsdShadeConnectableAPI to UsdLuxShapingAPI.

Member Function Documentation

USDLUX_API UsdSchemaKind UsdLuxShapingAPI::_GetSchemaKind ( ) const
overrideprotectedvirtual

Returns the kind of schema this class belongs to.

See Also
UsdSchemaKind

Reimplemented from UsdAPISchemaBase.

static USDLUX_API UsdLuxShapingAPI UsdLuxShapingAPI::Apply ( const UsdPrim &  prim)
static

Applies this single-apply API schema to the given prim. This information is stored by adding "ShapingAPI" to the token-valued, listOp metadata apiSchemas on the prim.

Returns
A valid UsdLuxShapingAPI object is returned upon success. An invalid (or empty) UsdLuxShapingAPI object is returned upon failure. See UsdPrim::ApplyAPI() for conditions resulting in failure.
See Also
UsdPrim::GetAppliedSchemas()
UsdPrim::HasAPI()
UsdPrim::CanApplyAPI()
UsdPrim::ApplyAPI()
UsdPrim::RemoveAPI()
static USDLUX_API bool UsdLuxShapingAPI::CanApply ( const UsdPrim &  prim,
std::string *  whyNot = nullptr 
)
static

Returns true if this single-apply API schema can be applied to the given prim. If this schema can not be a applied to the prim, this returns false and, if provided, populates whyNot with the reason it can not be applied.

Note that if CanApply returns false, that does not necessarily imply that calling Apply will fail. Callers are expected to call CanApply before calling Apply if they want to ensure that it is valid to apply a schema.

See Also
UsdPrim::GetAppliedSchemas()
UsdPrim::HasAPI()
UsdPrim::CanApplyAPI()
UsdPrim::ApplyAPI()
UsdPrim::RemoveAPI()
USDLUX_API UsdShadeConnectableAPI UsdLuxShapingAPI::ConnectableAPI ( ) const

Contructs and returns a UsdShadeConnectableAPI object with this shaping API prim. Note that a valid UsdLuxShapingAPI will only return a valid UsdShadeConnectableAPI if the its prim's Typed schema type is actually connectable.

USDLUX_API UsdShadeInput UsdLuxShapingAPI::CreateInput ( const TfToken &  name,
const SdfValueTypeName &  typeName 
)

Create an input which can either have a value or can be connected. The attribute representing the input is created in the "inputs:" namespace. Inputs on shaping API are connectable.

USDLUX_API UsdShadeOutput UsdLuxShapingAPI::CreateOutput ( const TfToken &  name,
const SdfValueTypeName &  typeName 
)

Create an output which can either have a value or can be connected. The attribute representing the output is created in the "outputs:" namespace. Outputs on a shaping API cannot be connected, as their value is assumed to be computed externally.

USDLUX_API UsdAttribute UsdLuxShapingAPI::CreateShapingConeAngleAttr ( VtValue const &  defaultValue = VtValue(),
bool  writeSparsely = false 
) const

See GetShapingConeAngleAttr(), and also Usd_Create_Or_Get_Property for when to use Get vs Create. If specified, author defaultValue as the attribute's default, sparsely (when it makes sense to do so) if writeSparsely is true - the default for writeSparsely is false.

USDLUX_API UsdAttribute UsdLuxShapingAPI::CreateShapingConeSoftnessAttr ( VtValue const &  defaultValue = VtValue(),
bool  writeSparsely = false 
) const

See GetShapingConeSoftnessAttr(), and also Usd_Create_Or_Get_Property for when to use Get vs Create. If specified, author defaultValue as the attribute's default, sparsely (when it makes sense to do so) if writeSparsely is true - the default for writeSparsely is false.

USDLUX_API UsdAttribute UsdLuxShapingAPI::CreateShapingFocusAttr ( VtValue const &  defaultValue = VtValue(),
bool  writeSparsely = false 
) const

See GetShapingFocusAttr(), and also Usd_Create_Or_Get_Property for when to use Get vs Create. If specified, author defaultValue as the attribute's default, sparsely (when it makes sense to do so) if writeSparsely is true - the default for writeSparsely is false.

USDLUX_API UsdAttribute UsdLuxShapingAPI::CreateShapingFocusTintAttr ( VtValue const &  defaultValue = VtValue(),
bool  writeSparsely = false 
) const

See GetShapingFocusTintAttr(), and also Usd_Create_Or_Get_Property for when to use Get vs Create. If specified, author defaultValue as the attribute's default, sparsely (when it makes sense to do so) if writeSparsely is true - the default for writeSparsely is false.

USDLUX_API UsdAttribute UsdLuxShapingAPI::CreateShapingIesAngleScaleAttr ( VtValue const &  defaultValue = VtValue(),
bool  writeSparsely = false 
) const

See GetShapingIesAngleScaleAttr(), and also Usd_Create_Or_Get_Property for when to use Get vs Create. If specified, author defaultValue as the attribute's default, sparsely (when it makes sense to do so) if writeSparsely is true - the default for writeSparsely is false.

USDLUX_API UsdAttribute UsdLuxShapingAPI::CreateShapingIesFileAttr ( VtValue const &  defaultValue = VtValue(),
bool  writeSparsely = false 
) const

See GetShapingIesFileAttr(), and also Usd_Create_Or_Get_Property for when to use Get vs Create. If specified, author defaultValue as the attribute's default, sparsely (when it makes sense to do so) if writeSparsely is true - the default for writeSparsely is false.

USDLUX_API UsdAttribute UsdLuxShapingAPI::CreateShapingIesNormalizeAttr ( VtValue const &  defaultValue = VtValue(),
bool  writeSparsely = false 
) const

See GetShapingIesNormalizeAttr(), and also Usd_Create_Or_Get_Property for when to use Get vs Create. If specified, author defaultValue as the attribute's default, sparsely (when it makes sense to do so) if writeSparsely is true - the default for writeSparsely is false.

static USDLUX_API UsdLuxShapingAPI UsdLuxShapingAPI::Get ( const UsdStagePtr &  stage,
const SdfPath &  path 
)
static

Return a UsdLuxShapingAPI holding the prim adhering to this schema at path on stage. If no prim exists at path on stage, or if the prim at that path does not adhere to this schema, return an invalid schema object. This is shorthand for the following:

UsdLuxShapingAPI(stage->GetPrimAtPath(path));
USDLUX_API UsdShadeInput UsdLuxShapingAPI::GetInput ( const TfToken &  name) const

Return the requested input if it exists.

USDLUX_API std::vector<UsdShadeInput> UsdLuxShapingAPI::GetInputs ( bool  onlyAuthored = true) const

Inputs are represented by attributes in the "inputs:" namespace. If onlyAuthored is true (the default), then only return authored attributes; otherwise, this also returns un-authored builtins.

USDLUX_API UsdShadeOutput UsdLuxShapingAPI::GetOutput ( const TfToken &  name) const

Return the requested output if it exists.

USDLUX_API std::vector<UsdShadeOutput> UsdLuxShapingAPI::GetOutputs ( bool  onlyAuthored = true) const

Outputs are represented by attributes in the "outputs:" namespace. If onlyAuthored is true (the default), then only return authored attributes; otherwise, this also returns un-authored builtins.

static USDLUX_API const TfTokenVector& UsdLuxShapingAPI::GetSchemaAttributeNames ( bool  includeInherited = true)
static

Return a vector of names of all pre-declared attributes for this schema class and all its ancestor classes. Does not include attributes that may be authored by custom/extended methods of the schemas involved.

USDLUX_API UsdAttribute UsdLuxShapingAPI::GetShapingConeAngleAttr ( ) const

Angular limit off the primary axis to restrict the light spread, in degrees.

Light emissions at angles off the primary axis greater than this are guaranteed to be zero, i.e.:

𝛳offAxis = acos(lightAxis • emissionDir)
𝛳cutoff = toRadians(coneAngle)
𝛳offAxis > 𝛳cutoff ⟹ LScalar = 0

For angles < coneAngle, see the documentation for shaping:cone:softness. However, at the default of coneSoftness = 0, the luminance is unaltered if emissionOffAxisAngle <= coneAngle, so the coneAngle functions as a hard binary "off" toggle for all angles > coneAngle.

Declaration float inputs:shaping:cone:angle = 90
C++ Type float
Usd Type SdfValueTypeNames->Float
USDLUX_API UsdAttribute UsdLuxShapingAPI::GetShapingConeSoftnessAttr ( ) const

Controls the cutoff softness for cone angle.

At the default of coneSoftness = 0, the luminance is unaltered if emissionOffAxisAngle <= coneAngle, and 0 if emissionOffAxisAngle > coneAngle, so in this situation the coneAngle functions as a hard binary "off" toggle for all angles > coneAngle.

For coneSoftness in the range (0, 1], it defines the proportion of the non-cutoff angles over which the luminance is smoothly interpolated from 0 to 1. Mathematically:

𝛳offAxis = acos(lightAxis • emissionDir)
𝛳cutoff = toRadians(coneAngle)
𝛳smoothStart = lerp(coneSoftness, 𝛳cutoff, 0)
LScalar = LScalar ⋅ (1 - smoothStep(𝛳offAxis, 𝛳smoothStart, 𝛳cutoff)

Values outside of the [0, 1] range are clamped to the range.

Declaration float inputs:shaping:cone:softness = 0
C++ Type float
Usd Type SdfValueTypeNames->Float
USDLUX_API UsdAttribute UsdLuxShapingAPI::GetShapingFocusAttr ( ) const

A control to shape the spread of light. Higher focus values pull light towards the center and narrow the spread.

This is implemented as a multiplication with the absolute value of the dot product between the light's surface normal and the emission direction, raised to the power focus. See inputs:shaping:focusTint for the complete formula, but if we assume a default focusTint of pure black, then that formula simplifies to:

focusFactor = ｜emissionDirection • lightNormal｜focus
LColor = focusFactor ⋅ LColor

Values < 0 are ignored.

Declaration float inputs:shaping:focus = 0
C++ Type float
Usd Type SdfValueTypeNames->Float
USDLUX_API UsdAttribute UsdLuxShapingAPI::GetShapingFocusTintAttr ( ) const

Off-axis color tint. This tints the emission in the falloff region. The default tint is black.

This is implemented as a linear interpolation between focusTint and white, by the factor computed from the focus attribute, in other words:

focusFactor = ｜emissionDirection • lightNormal｜focus
focusColor = lerp(focusFactor, focusTint, [1, 1, 1])
LColor = componentwiseMultiply(focusColor, LColor)

Note that this implies that a focusTint of pure white will disable focus.

Declaration color3f inputs:shaping:focusTint = (0, 0, 0)
C++ Type GfVec3f
Usd Type SdfValueTypeNames->Color3f
USDLUX_API UsdAttribute UsdLuxShapingAPI::GetShapingIesAngleScaleAttr ( ) const

Rescales the angular distribution of the IES profile.

Applies a scaling factor to the latitudinal theta/vertical polar coordinate before sampling the IES profile, to shift the samples more toward the "top" or "bottom" of the profile. The scaling origin varies depending on whether angleScale is positive or negative. If it is positive, the scaling origin is theta = 0. If it is negative, the scaling origin is theta = pi (180 degrees). Values where |angleScale| < 1 will "shrink" the angular range in which the iesProfile is applied, while values where |angleScale| > 1 will "grow" the angular range to which the iesProfile is mapped.

If 𝛳light is the latitudinal theta polar coordinate of the emission direction in the light's local space, and 𝛳ies is the value that will be used when actually sampling the profile, then the exact formula is:

  • if angleScale > 0:
    𝛳ies = 𝛳light / angleScale
  • if angleScale = 0:
    𝛳ies = 𝛳light
  • if angleScale < 0:
    𝛳ies = (𝛳light - π) / -angleScale

Usage guidelines for artists / lighting TDs:

If you have an IES profile for a spotlight aimed "down":

  • You should use a positive angleScale (> 0).
  • Values where 0 < angleScale < 1 will narrow the spotlight beam.
  • Values where angleScale > 1 will broaden the spotlight beam.

For example, if the original IES profile is a downward spotlight with a total cone angle of 60°, then angleScale = .5 will narrow it to have a cone angle of 30°, and an angleScale of 1.5 will broaden it to have a cone angle of 90°.

If you have an IES profile for a spotlight aimed "up":

  • You should use a negative angleScale (< 0).
  • Values where -1 < angleScale < 0 will narrow the spotlight beam.
  • Values where angleScale < -1 will broaden the spotlight beam.

For example, if the original IES profile is an upward spotlight with a total cone angle of 60°, then angleScale = -.5 will narrow it to have a cone angle of 30°, and an angleScale of -1.5 will broaden it to have a cone angle of 90°.

If you have an IES profile that's isn't clearly "aimed" in a single direction, OR it's aimed in a direction other than straight up or down:

  • Applying angleScale will alter the vertical angle mapping for your IES light, but it may be difficult to have a clear intuitive sense of how varying the angleScale will affect the shape of your light

If you violate the above rules (i.e., use a negative angleScale for a spotlight aimed down), then angleScale will still alter the vertical- angle mapping, but in more non-intuitive ways (i.e., broadening / narrowing may seem inverted, and the IES profile may seem to "translate" through the vertical angles, rather than uniformly scale).

Declaration float inputs:shaping:ies:angleScale = 0
C++ Type float
Usd Type SdfValueTypeNames->Float
USDLUX_API UsdAttribute UsdLuxShapingAPI::GetShapingIesFileAttr ( ) const

An IES (Illumination Engineering Society) light profile describing the angular distribution of light.

For full details on the .ies file format, see the full specification, ANSI/IES LM-63-19:

https://store.ies.org/product/lm-63-19-approved-method-ies-standard-file-format-for-the-electronic-transfer-of-photometric-data-and-related-information/

The luminous intensity values in the IES profile are sampled using the emission direction in the light's local space (after a possible transformation by a non-zero shaping:ies:angleScale, see below). The sampled value is then potentially normalized by the overall power of the profile if shaping:ies:normalize is enabled, and then used as a scaling factor on the returned luminance:

𝛳light, 𝜙 = toPolarCoordinates(emissionDirectionInLightSpace)
𝛳ies = applyAngleScale(𝛳light, angleScale)
iesSample = sampleIES(iesFile, 𝛳ies, 𝜙)
iesNormalize ⟹ iesSample = iesSample ⋅ iesProfilePower(iesFile)
LColor = iesSample ⋅ LColor

See inputs:shaping:ies:angleScale for a description of applyAngleScale, and inputs:shaping:ies:normalize for how iesProfilePower is calculated.

Declaration asset inputs:shaping:ies:file
C++ Type SdfAssetPath
Usd Type SdfValueTypeNames->Asset
USDLUX_API UsdAttribute UsdLuxShapingAPI::GetShapingIesNormalizeAttr ( ) const

Normalizes the IES profile so that it affects the shaping of the light while preserving the overall energy output.

The sampled luminous intensity is scaled by the overall power of the IES profile if this is on, where the total power is calculated by integrating the luminous intensity over all solid angle patches defined in the profile.

Declaration bool inputs:shaping:ies:normalize = 0
C++ Type bool
Usd Type SdfValueTypeNames->Bool

Friends And Related Function Documentation

friend class UsdSchemaRegistry
friend

Definition at line 141 of file shapingAPI.h.

Member Data Documentation

const UsdSchemaKind UsdLuxShapingAPI::schemaKind = UsdSchemaKind::SingleApplyAPI
static

Compile time constant representing what kind of schema this class is.

See Also
UsdSchemaKind

Definition at line 49 of file shapingAPI.h.

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