UsdShadeShader Class Reference

#include <shader.h>

Inheritance diagram for UsdShadeShader:

Public Member Functions
	UsdShadeShader (const UsdPrim &prim=UsdPrim())
	UsdShadeShader (const UsdSchemaBase &schemaObj)
virtual USDSHADE_API	~UsdShadeShader ()
	Destructor. More...
USDSHADE_API UsdAttribute	GetImplementationSourceAttr () const
USDSHADE_API UsdAttribute	CreateImplementationSourceAttr (VtValue const &defaultValue=VtValue(), bool writeSparsely=false) const
USDSHADE_API UsdAttribute	GetIdAttr () const
USDSHADE_API UsdAttribute	CreateIdAttr (VtValue const &defaultValue=VtValue(), bool writeSparsely=false) const
USDSHADE_API	UsdShadeShader (const UsdShadeConnectableAPI &connectable)
USDSHADE_API UsdShadeConnectableAPI	ConnectableAPI () const
USDSHADE_API SdrShaderNodeConstPtr	GetShaderNodeForSourceType (const TfToken &sourceType) const
Outputs API
Outputs represent a typed attribute on a shader or node-graph whose value is computed externally. When they exist on a node-graph, they are connectable and are typically connected to the output of a shader within the node-graph.
USDSHADE_API UsdShadeOutput	CreateOutput (const TfToken &name, const SdfValueTypeName &typeName)
USDSHADE_API UsdShadeOutput	GetOutput (const TfToken &name) const
USDSHADE_API std::vector < UsdShadeOutput >	GetOutputs () const
Inputs API
Inputs are connectable attribute with a typed value. On shaders, the shader parameters are encoded as inputs. On node-graphs, interface attributes are represented as inputs.
USDSHADE_API UsdShadeInput	CreateInput (const TfToken &name, const SdfValueTypeName &typeName)
USDSHADE_API UsdShadeInput	GetInput (const TfToken &name) const
USDSHADE_API std::vector < UsdShadeInput >	GetInputs () const
Shader Source API
This section provides API for identifying the source of a shader's implementation.
USDSHADE_API TfToken	GetImplementationSource () const
USDSHADE_API bool	SetShaderId (const TfToken &id) const
USDSHADE_API bool	GetShaderId (TfToken *id) const
USDSHADE_API bool	SetSourceAsset (const SdfAssetPath &sourceAsset, const TfToken &sourceType=UsdShadeTokens->universalSourceType) const
USDSHADE_API bool	GetSourceAsset (SdfAssetPath *sourceAsset, const TfToken &sourceType=UsdShadeTokens->universalSourceType) const
USDSHADE_API bool	SetSourceAssetSubIdentifier (const TfToken &subIdentifier, const TfToken &sourceType=UsdShadeTokens->universalSourceType) const
USDSHADE_API bool	GetSourceAssetSubIdentifier (TfToken *subIdentifier, const TfToken &sourceType=UsdShadeTokens->universalSourceType) const
USDSHADE_API bool	SetSourceCode (const std::string &sourceCode, const TfToken &sourceType=UsdShadeTokens->universalSourceType) const
USDSHADE_API bool	GetSourceCode (std::string *sourceCode, const TfToken &sourceType=UsdShadeTokens->universalSourceType) const
Shader Sdr Metadata API
This section provides API for authoring and querying shader registry metadata. When the shader's implementationSource is sourceAsset or sourceCode, the authored "sdrMetadata" dictionary value provides additional metadata needed to process the shader source correctly. It is used in combination with the sourceAsset or sourceCode value to fetch the appropriate node from the shader registry. We expect the keys in sdrMetadata to correspond to the keys in SdrNodeMetadata. However, this is not strictly enforced in the API. The only allowed value type in the "sdrMetadata" dictionary is a std::string since it needs to be converted into a NdrTokenMap, which Sdr will parse using the utilities available in SdrMetadataHelpers.
USDSHADE_API NdrTokenMap	GetSdrMetadata () const
USDSHADE_API std::string	GetSdrMetadataByKey (const TfToken &key) const
USDSHADE_API void	SetSdrMetadata (const NdrTokenMap &sdrMetadata) const
USDSHADE_API void	SetSdrMetadataByKey (const TfToken &key, const std::string &value) const
USDSHADE_API bool	HasSdrMetadata () const
USDSHADE_API bool	HasSdrMetadataByKey (const TfToken &key) const
USDSHADE_API void	ClearSdrMetadata () const
USDSHADE_API void	ClearSdrMetadataByKey (const TfToken &key) const
Public Member Functions inherited from UsdTyped
	UsdTyped (const UsdPrim &prim=UsdPrim())
	UsdTyped (const UsdSchemaBase &schemaObj)
virtual USD_API	~UsdTyped ()
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
UsdSchemaType	GetSchemaType () const
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 USDSHADE_API const TfTokenVector &	GetSchemaAttributeNames (bool includeInherited=true)
static USDSHADE_API UsdShadeShader	Get (const UsdStagePtr &stage, const SdfPath &path)
static USDSHADE_API UsdShadeShader	Define (const UsdStagePtr &stage, const SdfPath &path)
Static Public Member Functions inherited from UsdTyped
static const TfTokenVector &	GetSchemaAttributeNames (bool includeInherited=true)
static USD_API UsdTyped	Get (const UsdStagePtr &stage, const SdfPath &path)
Static Public Member Functions inherited from UsdSchemaBase
static const TfTokenVector &	GetSchemaAttributeNames (bool includeInherited=true)

Static Public Attributes
static const UsdSchemaType	schemaType = UsdSchemaType::ConcreteTyped
Static Public Attributes inherited from UsdTyped
static const UsdSchemaType	schemaType = UsdSchemaType::AbstractBase
Static Public Attributes inherited from UsdSchemaBase
static const UsdSchemaType	schemaType = UsdSchemaType::AbstractBase

Protected Member Functions
USDSHADE_API UsdSchemaType	_GetSchemaType () const override
Protected Member Functions inherited from UsdTyped
USD_API bool	_IsCompatible () const override
Protected Member Functions inherited from UsdSchemaBase
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

Detailed Description

Base class for all USD shaders. Shaders are the building blocks of shading networks. While UsdShadeShader objects are not target specific, each renderer or application target may derive its own renderer-specific shader object types from this base, if needed.

Objects of this class generally represent a single shading object, whether it exists in the target renderer or not. For example, a texture, a fractal, or a mix node.

The main property of this class is the info:id token, which uniquely identifies the type of this node. The id resolution into a renderable shader target is deferred to the consuming application.

The purpose of representing them in Usd is two-fold:

• To represent, via "connections" the topology of the shading network that must be reconstructed in the renderer. Facilities for authoring and manipulating connections are encapsulated in the Has-A schema UsdShadeConnectableAPI.
• To present a (partial or full) interface of typed input parameters whose values can be set and overridden in Usd, to be provided later at render-time as parameter values to the actual render shader objects. Shader input parameters are encapsulated in the property schema UsdShadeInput.

For any described attribute Fallback Value or Allowed Values below that are text/tokens, the actual token is published and defined in UsdShadeTokens. So to set an attribute to the value "rightHanded", use UsdShadeTokens->rightHanded as the value.

Definition at line 89 of file shader.h.

Constructor & Destructor Documentation

UsdShadeShader::UsdShadeShader ( const UsdPrim &  prim = UsdPrim() )

inlineexplicit

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

Definition at line 101 of file shader.h.

UsdShadeShader::UsdShadeShader ( const UsdSchemaBase &  schemaObj )

inlineexplicit

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

Definition at line 109 of file shader.h.

virtual USDSHADE_API UsdShadeShader::~UsdShadeShader ( )

virtual

Destructor.

USDSHADE_API UsdShadeShader::UsdShadeShader

(

const UsdShadeConnectableAPI &

connectable

)

Constructor that takes a ConnectableAPI object. Allow implicit (auto) conversion of UsdShadeShader to UsdShadeConnectableAPI, so that a shader can be passed into any function that accepts a ConnectableAPI.

Member Function Documentation

USDSHADE_API UsdSchemaType UsdShadeShader::_GetSchemaType ( ) const

overrideprotectedvirtual

Returns the type of schema this class belongs to.

See Also

UsdSchemaType

Reimplemented from UsdSchemaBase.

USDSHADE_API void UsdShadeShader::ClearSdrMetadata

(

)

const

Clears any "sdrMetadata" value authored on the shader in the current EditTarget.

USDSHADE_API void UsdShadeShader::ClearSdrMetadataByKey

(

const TfToken &

key

)

const

Clears the entry corresponding to the given key in the "sdrMetadata" dictionary authored in the current EditTarget.

USDSHADE_API UsdShadeConnectableAPI UsdShadeShader::ConnectableAPI

(

)

const

Contructs and returns a UsdShadeConnectableAPI object with this shader.

Note that most tasks can be accomplished without explicitly constructing a UsdShadeConnectable API, since connection-related API such as UsdShadeConnectableAPI::ConnectToSource() are static methods, and UsdShadeShader will auto-convert to a UsdShadeConnectableAPI when passed to functions that want to act generically on a connectable UsdShadeConnectableAPI object.

USDSHADE_API UsdAttribute UsdShadeShader::CreateIdAttr	(	VtValue const &	defaultValue = VtValue(),
		bool	writeSparsely = false
	)		const

See GetIdAttr(), 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.

USDSHADE_API UsdAttribute UsdShadeShader::CreateImplementationSourceAttr	(	VtValue const &	defaultValue = VtValue(),
		bool	writeSparsely = false
	)		const

See GetImplementationSourceAttr(), 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.

USDSHADE_API UsdShadeInput UsdShadeShader::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 both shaders and node-graphs are connectable.

USDSHADE_API UsdShadeOutput UsdShadeShader::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 shader cannot be connected, as their value is assumed to be computed externally.

static USDSHADE_API UsdShadeShader UsdShadeShader::Define ( const UsdStagePtr &  stage, const SdfPath &  path  )

static

Attempt to ensure a UsdPrim adhering to this schema at path is defined (according to UsdPrim::IsDefined()) on this stage.

If a prim adhering to this schema at path is already defined on this stage, return that prim. Otherwise author an SdfPrimSpec with specifier == SdfSpecifierDef and this schema's prim type name for the prim at path at the current EditTarget. Author SdfPrimSpec s with specifier == SdfSpecifierDef and empty typeName at the current EditTarget for any nonexistent, or existing but not Defined ancestors.

The given path must be an absolute prim path that does not contain any variant selections.

If it is impossible to author any of the necessary PrimSpecs, (for example, in case path cannot map to the current UsdEditTarget's namespace) issue an error and return an invalid UsdPrim.

Note that this method may return a defined prim whose typeName does not specify this schema class, in case a stronger typeName opinion overrides the opinion at the current EditTarget.

static USDSHADE_API UsdShadeShader UsdShadeShader::Get ( const UsdStagePtr &  stage, const SdfPath &  path  )

static

Return a UsdShadeShader 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:

UsdShadeShader(stage->GetPrimAtPath(path));

USDSHADE_API UsdAttribute UsdShadeShader::GetIdAttr

(

)

const

The id is an identifier for the type or purpose of the shader. E.g.: Texture or FractalFloat. The use of this id will depend on the render target: some will turn it into an actual shader path, some will use it to generate shader source code dynamically.

See Also

SetShaderId()

Declaration	uniform token info:id
C++ Type	TfToken
Usd Type	SdfValueTypeNames->Token
Variability	SdfVariabilityUniform

USDSHADE_API TfToken UsdShadeShader::GetImplementationSource

(

)

const

Reads the value of info:implementationSource attribute and returns a token identifying the attribute that must be consulted to identify the shader's source program.

This returns

• id, to indicate that the "info:id" attribute must be consulted.
• sourceAsset to indicate that the asset-valued "info:{sourceType}:sourceAsset" attribute associated with the desired sourceType should be consulted to locate the asset with the shader's source.
• sourceCode to indicate that the string-valued "info:{sourceType}:sourceCode" attribute associated with the desired sourceType should be read to get shader's source.

This issues a warning and returns id if the info:implementationSource attribute has an invalid value.

{sourceType} above is a place holder for a token that identifies the type of shader source or its implementation. For example: osl, glslfx, riCpp etc. This allows a shader to specify different sourceAsset (or sourceCode) values for different sourceTypes. The sourceType tokens usually correspond to the sourceType value of the NdrParserPlugin that's used to parse the shader source (NdrParserPlugin::SourceType).

When sourceType is empty, the corresponding sourceAsset or sourceCode is considered to be "universal" (or fallback), which is represented by the empty-valued token UsdShadeTokens->universalSourceType. When the sourceAsset (or sourceCode) corresponding to a specific, requested sourceType is unavailable, the universal sourceAsset (or sourceCode) is returned by GetSourceAsset (and GetSourceCode} API, if present.

See Also

GetShaderId()

GetSourceAsset()

GetSourceCode()

USDSHADE_API UsdAttribute UsdShadeShader::GetImplementationSourceAttr

(

)

const

Specifies the attribute that should be consulted to get the shader's implementation or its source code.

• If set to "id", the "info:id" attribute's value is used to determine the shader source from the shader registry.
• If set to "sourceAsset", the resolved value of the "info:sourceAsset" attribute corresponding to the desired implementation (or source-type) is used to locate the shader source. A source asset file may also specify multiple shader definitions, so there is an optional attribute "info:sourceAsset:subIdentifier" whose value should be used to indicate a particular shader definition from a source asset file.
• If set to "sourceCode", the value of "info:sourceCode" attribute corresponding to the desired implementation (or source type) is used as the shader source.

Declaration	uniform token info:implementationSource = "id"
C++ Type	TfToken
Usd Type	SdfValueTypeNames->Token
Variability	SdfVariabilityUniform
Allowed Values	id, sourceAsset, sourceCode

USDSHADE_API UsdShadeInput UsdShadeShader::GetInput

(

const TfToken &

name

)

const

Return the requested input if it exists.

USDSHADE_API std::vector<UsdShadeInput> UsdShadeShader::GetInputs

(

)

const

Inputs are represented by attributes in the "inputs:" namespace.

USDSHADE_API UsdShadeOutput UsdShadeShader::GetOutput

(

const TfToken &

name

)

const

Return the requested output if it exists.

USDSHADE_API std::vector<UsdShadeOutput> UsdShadeShader::GetOutputs

(

)

const

Outputs are represented by attributes in the "outputs:" namespace.

static USDSHADE_API const TfTokenVector& UsdShadeShader::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.

USDSHADE_API NdrTokenMap UsdShadeShader::GetSdrMetadata

(

)

const

Returns this shader's composed "sdrMetadata" dictionary as a NdrTokenMap.

USDSHADE_API std::string UsdShadeShader::GetSdrMetadataByKey

(

const TfToken &

key

)

const

Returns the value corresponding to key in the composed sdrMetadata dictionary.

USDSHADE_API bool UsdShadeShader::GetShaderId

(

TfToken *

id

)

const

Fetches the shader's ID value from the info:id attribute, if the shader's info:implementationSource is id.

Returns true if the shader's implementation source is id and the value was fetched properly into id. Returns false otherwise.

See Also

GetImplementationSource()

USDSHADE_API SdrShaderNodeConstPtr UsdShadeShader::GetShaderNodeForSourceType

(

const TfToken &

sourceType

)

const

This method attempts to ensure that there is a ShaderNode in the shader registry (i.e. SdrRegistry) representing this shader for the given sourceType. It may return a null pointer if none could be found or created.

USDSHADE_API bool UsdShadeShader::GetSourceAsset	(	SdfAssetPath *	sourceAsset,
		const TfToken &	sourceType = UsdShadeTokens->universalSourceType
	)		const

Fetches the shader's source asset value for the specified sourceType value from the info:sourceType:sourceAsset attribute, if the shader's info:implementationSource is sourceAsset.

If the sourceAsset attribute corresponding to the requested sourceType isn't present on the shader, then the universal fallback sourceAsset attribute, i.e. info:sourceAsset is consulted, if present, to get the source asset path.

Returns true if the shader's implementation source is sourceAsset and the source asset path value was fetched successfully into sourceAsset. Returns false otherwise.

See Also

GetImplementationSource()

USDSHADE_API bool UsdShadeShader::GetSourceAssetSubIdentifier	(	TfToken *	subIdentifier,
		const TfToken &	sourceType = UsdShadeTokens->universalSourceType
	)		const

Fetches the shader's sub-identifier for the source asset with the specified sourceType value from the info:sourceType: sourceAsset:subIdentifier attribute, if the shader's info: implementationSource is sourceAsset.

If the subIdentifier attribute corresponding to the requested sourceType isn't present on the shader, then the universal fallback sub-identifier attribute, i.e. info:sourceAsset: subIdentifier is consulted, if present, to get the sub-identifier name.

Returns true if the shader's implementation source is sourceAsset and the sub-identifier for the given source type was fetched successfully into subIdentifier. Returns false otherwise.

USDSHADE_API bool UsdShadeShader::GetSourceCode	(	std::string *	sourceCode,
		const TfToken &	sourceType = UsdShadeTokens->universalSourceType
	)		const

Fetches the shader's source code for the specified sourceType value by reading the info:sourceType:sourceCode attribute, if the shader's info:implementationSource is sourceCode.

If the sourceCode attribute corresponding to the requested sourceType isn't present on the shader, then the universal or fallback sourceCode attribute (i.e. info:sourceCode) is consulted, if present, to get the source code.

Returns true if the shader's implementation source is sourceCode and the source code string was fetched successfully into sourceCode. Returns false otherwise.

See Also

GetImplementationSource()

USDSHADE_API bool UsdShadeShader::HasSdrMetadata

(

)

const

Returns true if the shader has a non-empty composed "sdrMetadata" dictionary value.

USDSHADE_API bool UsdShadeShader::HasSdrMetadataByKey

(

const TfToken &

key

)

const

Returns true if there is a value corresponding to the given key in the composed "sdrMetadata" dictionary.

USDSHADE_API void UsdShadeShader::SetSdrMetadata

(

const NdrTokenMap &

sdrMetadata

)

const

Authors the given sdrMetadata on this shader at the current EditTarget.

USDSHADE_API void UsdShadeShader::SetSdrMetadataByKey	(	const TfToken &	key,
		const std::string &	value
	)		const

Sets the value corresponding to key to the given string value, in the shader's "sdrMetadata" dictionary at the current EditTarget.

USDSHADE_API bool UsdShadeShader::SetShaderId

(

const TfToken &

id

)

const

Sets the shader's ID value. This also sets the info:implementationSource attribute on the shader to UsdShadeTokens->id, if the existing value is different.

USDSHADE_API bool UsdShadeShader::SetSourceAsset	(	const SdfAssetPath &	sourceAsset,
		const TfToken &	sourceType = UsdShadeTokens->universalSourceType
	)		const

Sets the shader's source-asset path value to sourceAsset for the given source type, sourceType.

This also sets the info:implementationSource attribute on the shader to UsdShadeTokens->sourceAsset.

USDSHADE_API bool UsdShadeShader::SetSourceAssetSubIdentifier	(	const TfToken &	subIdentifier,
		const TfToken &	sourceType = UsdShadeTokens->universalSourceType
	)		const

Set a sub-identifier to be used with a source asset of the given source type. This sets the info:sourceType:sourceAsset:subIdentifier .

This also sets the info:implementationSource attribute on the shader to UsdShadeTokens->sourceAsset

USDSHADE_API bool UsdShadeShader::SetSourceCode	(	const std::string &	sourceCode,
		const TfToken &	sourceType = UsdShadeTokens->universalSourceType
	)		const

Sets the shader's source-code value to sourceCode for the given source type, sourceType.

This also sets the info:implementationSource attribute on the shader to UsdShadeTokens->sourceCode.

Friends And Related Function Documentation

friend class UsdSchemaRegistry

friend

Definition at line 173 of file shader.h.

Member Data Documentation

const UsdSchemaType UsdShadeShader::schemaType = UsdSchemaType::ConcreteTyped

static

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

See Also

UsdSchemaType

Definition at line 95 of file shader.h.

---

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

• pxr/usd/usdShade/shader.h