usdrt::UsdLuxLight

Defined in usdrt/scenegraph/usd/usdLux/light.h

class UsdLuxLight : public usdrt::UsdGeomXformable 

Base class for all lights.

Linking

Lights can be linked to geometry. Linking controls which geometry a light illuminates, and which geometry casts shadows from the light.

Linking is specified as collections (UsdCollectionAPI) which can be accessed via GetLightLinkCollection() and GetShadowLinkCollection(). Note that these collections have their includeRoot set to true, so that lights will illuminate and cast shadows from all objects by default. To illuminate only a specific set of objects, there are two options. One option is to modify the collection paths to explicitly exclude everything else, assuming it is known; the other option is to set includeRoot to false and explicitly include the desired objects. These are complementary approaches that may each be preferable depending on the scenario and how to best express the intent of the light setup.

Public Functions

inline explicit UsdLuxLight(const UsdPrim &prim = UsdPrim()): Construct a UsdLuxLight on UsdPrim prim . Equivalent to UsdLuxLight::Get(prim.GetStage(), prim.GetPath()) for a valid prim, but will not immediately throw an error for an invalid prim.

inline explicit UsdLuxLight(const UsdSchemaBase &schemaObj): Construct a UsdLuxLight on the prim held by schemaObj . Should be preferred over UsdLuxLight(schemaObj.GetPrim()), as it preserves SchemaBase state.

inline virtual ~UsdLuxLight(): Destructor.

inline UsdAttribute GetIntensityAttr() const

Scales the power of the light linearly.


Declaration	`float intensity = 1`
C++ Type	float
Usd Type	SdfValueTypeNames->Float

inline UsdAttribute CreateIntensityAttr() const: See GetIntensityAttr(), and also Create vs Get Property Methods 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.

inline UsdAttribute GetExposureAttr() const

Scales the power of the light exponentially as a power of 2 (similar to an F-stop control over exposure). The result is multiplied against the intensity.


Declaration	`float exposure = 0`
C++ Type	float
Usd Type	SdfValueTypeNames->Float

inline UsdAttribute CreateExposureAttr() const: See GetExposureAttr(), and also Create vs Get Property Methods 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.

inline UsdAttribute GetDiffuseAttr() const

A multiplier for the effect of this light on the diffuse response of materials. This is a non-physical control.


Declaration	`float diffuse = 1`
C++ Type	float
Usd Type	SdfValueTypeNames->Float

inline UsdAttribute CreateDiffuseAttr() const: See GetDiffuseAttr(), and also Create vs Get Property Methods 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.

inline UsdAttribute GetSpecularAttr() const

A multiplier for the effect of this light on the specular response of materials. This is a non-physical control.


Declaration	`float specular = 1`
C++ Type	float
Usd Type	SdfValueTypeNames->Float

inline UsdAttribute CreateSpecularAttr() const: See GetSpecularAttr(), and also Create vs Get Property Methods 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.

inline UsdAttribute GetNormalizeAttr() const

Normalizes power by the surface area of the light. This makes it easier to independently adjust the power and shape of the light, by causing the power to not vary with the area or angular size of the light.


Declaration	`bool normalize = 0`
C++ Type	bool
Usd Type	SdfValueTypeNames->Bool

inline UsdAttribute CreateNormalizeAttr() const: See GetNormalizeAttr(), and also Create vs Get Property Methods 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.

inline UsdAttribute GetColorAttr() const

The color of emitted light, in energy-linear terms.


Declaration	`color3f color = (1, 1, 1)`
C++ Type	GfVec3f
Usd Type	SdfValueTypeNames->Color3f

inline UsdAttribute CreateColorAttr() const: See GetColorAttr(), and also Create vs Get Property Methods 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.

inline UsdAttribute GetEnableColorTemperatureAttr() const

Enables using colorTemperature.


Declaration	`bool enableColorTemperature = 0`
C++ Type	bool
Usd Type	SdfValueTypeNames->Bool

inline UsdAttribute CreateEnableColorTemperatureAttr() const: See GetEnableColorTemperatureAttr(), and also Create vs Get Property Methods 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.

inline UsdAttribute GetColorTemperatureAttr() const

Color temperature, in degrees Kelvin, representing the white point. The default is a common white point, D65. Lower values are warmer and higher values are cooler. The valid range is from 1000 to 10000. Only takes effect when enableColorTemperature is set to true. When active, the computed result multiplies against the color attribute. See UsdLuxBlackbodyTemperatureAsRgb().


Declaration	`float colorTemperature = 6500`
C++ Type	float
Usd Type	SdfValueTypeNames->Float

inline UsdAttribute CreateColorTemperatureAttr() const: See GetColorTemperatureAttr(), and also Create vs Get Property Methods 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.

inline UsdRelationship GetFiltersRel() const: Relationship to the light filters that apply to this light.

inline UsdRelationship CreateFiltersRel() const: See GetFiltersRel(), and also Create vs Get Property Methods for when to use Get vs Create.

inline UsdAttribute GetXformOpOrderAttr() const

Encodes the sequence of transformation operations in the order in which they should be pushed onto a transform stack while visiting a UsdStage’s prims in a graph traversal that will effect the desired positioning for this prim and its descendant prims.

You should rarely, if ever, need to manipulate this attribute directly. It is managed by the AddXformOp(), SetResetXformStack(), and SetXformOpOrder(), and consulted by GetOrderedXformOps() and GetLocalTransformation().


Declaration	`uniform token[] xformOpOrder`
C++ Type	VtArray<TfToken>
Usd Type	SdfValueTypeNames->TokenArray
Variability	SdfVariabilityUniform

inline UsdAttribute CreateXformOpOrderAttr() const: See GetXformOpOrderAttr(), and also Create vs Get Property Methods 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.

inline UsdAttribute GetVisibilityAttr() const

Visibility is meant to be the simplest form of “pruning” visibility that is supported by most DCC apps. Visibility is animatable, allowing a sub-tree of geometry to be present for some segment of a shot, and absent from others; unlike the action of deactivating geometry prims, invisible geometry is still available for inspection, for positioning, for defining volumes, etc.


Declaration	`token visibility = "inherited"`
C++ Type	TfToken
Usd Type	SdfValueTypeNames->Token
Allowed Values	inherited, invisible

inline UsdAttribute CreateVisibilityAttr() const: See GetVisibilityAttr(), and also Create vs Get Property Methods 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.

inline UsdAttribute GetPurposeAttr() const

Purpose is a classification of geometry into categories that can each be independently included or excluded from traversals of prims on a stage, such as rendering or bounding-box computation traversals.

See UsdGeom_ImageablePurpose for more detail about how purpose is computed and used.


Declaration	`uniform token purpose = "default"`
C++ Type	TfToken
Usd Type	SdfValueTypeNames->Token
Variability	SdfVariabilityUniform
Allowed Values	default, render, proxy, guide

inline UsdAttribute CreatePurposeAttr() const: See GetPurposeAttr(), and also Create vs Get Property Methods 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.

inline UsdRelationship GetProxyPrimRel() const

The proxyPrim relationship allows us to link a prim whose purpose is “render” to its (single target) purpose=”proxy” prim. This is entirely optional, but can be useful in several scenarios:

In a pipeline that does pruning (for complexity management) by deactivating prims composed from asset references, when we deactivate a purpose=”render” prim, we will be able to discover and additionally deactivate its associated purpose=”proxy” prim, so that preview renders reflect the pruning accurately.

DCC importers may be able to make more aggressive optimizations for interactive processing and display if they can discover the proxy for a given render prim.

With a little more work, a Hydra-based application will be able to map a picked proxy prim back to its render geometry for selection.

Note

It is only valid to author the proxyPrim relationship on prims whose purpose is “render”.

inline UsdRelationship CreateProxyPrimRel() const: See GetProxyPrimRel(), and also Create vs Get Property Methods for when to use Get vs Create.

UsdPrim GetPrim() const: Return this schema object’s held prim.

SdfPath GetPath() const: Return the SdfPath to this schema object’s held prim.

inline explicit operator bool() const

Check if this schema object is compatible with it’s held prim and that the prim is valid.

A typed schema object is compatible if the held prim’s type is or is a subtype of the schema’s type. Based on prim.IsA().

An API schema object is compatible if the API is of type SingleApplyAPI or UsdSchemaType::MultipleApplyAPI, and the schema has been applied to the prim. Based on prim.HasAPI.

This method invokes polymorphic behaviour.