Provides access to Evaluation Manager node information. More...

#include <MEvaluationNode.h>

Public Member Functions
	~MEvaluationNode ()
	Destructor.

	MEvaluationNode (const MEvaluationNode &evalNode)
	Copy Constructor. More...

int	parentCount () const
	Returns the number of parent nodes this evaluation node has. More...

MEvaluationNode	parent (int index) const
	Returns the parent node of this evaluation node at given index. More...

int	childCount () const
	Returns the number of children nodes this evaluation node has. More...

MEvaluationNode	child (int index) const
	Returns the child node of this evaluation node at given index. More...

MEvaluationNodeIterator	iterator (MStatus *ReturnStatus=nullptr) const
	Returns an iterator at the beginning of the dirty plug list. More...

bool	dirtyPlugExists (const MObject &attribute, MStatus *ReturnStatus=nullptr) const
	Returns true if the specified attribute has a dirty plug. More...

MPlug	dirtyPlug (const MObject &attribute, MStatus *ReturnStatus=nullptr) const
	Returns the top-most plug for the specified attribute if the attribute has dirty plugs. More...

MObject	dependencyNode (MStatus *ReturnStatus=nullptr) const
	Returns the dependency node this evaluation node represents. More...

MDataBlock	datablock (MStatus *ReturnStatus=nullptr) const
	Returns the datablock for this node. More...

void	connect (MEvaluationNode &child, MStatus *ReturnStatus=nullptr)
	Connect two generic evaluation nodes. More...

void	skipEvaluation (const MObject &attribute, bool allowSingleDownstreamDependency=false, MStatus *ReturnStatus=nullptr) const
	Hint the Evaluation Manager that the attribute can be skipped for the current evaluation. More...

bool	skippingEvaluation (const MObject &attribute, MStatus *ReturnStatus=nullptr) const
	Returns true if the attribute was marked to be skipped. More...

Static Public Member Functions
static const char *	className ()
	Returns the name of this class. More...

Detailed Description

Provides access to Evaluation Manager node information.

See also: MEvaluationNodeIterator

An evaluation node and the connections between them form an evaluation graph. Each evaluation context uses a unique evaluation graph with its own set of evaluation nodes. Evaluation graphs are scheduled to speed up the operations within Maya.

This class contains methods for querying which attributes or plugs on a node will be set dirty prior to evaluation by the evaluation manager.

It is sometimes necessary to know the dirty state of plugs/attributes if your node is handling custom information. This handling would be done in the MPxNode preEvaluation()/postEvaluation() methods.

If you need to access the list of dirty plugs in the evaluation node then use the internal iterator:

for( MEvaluationNodeIterator nodeIt = theNode.iterator(); ! nodeIt.isDone(); nodeIt.next() ) { doSomePlugThing( nodeIt.plug() ); }

Examples:: apiMeshShape/apiMeshShape.cpp, apiMeshShape/apiMeshShape.h, basicMorphNode/basicMorphNode.cpp, constraintEvaluator/constraintEvaluator.cpp, evaluationPruningEvaluator/evaluationPruningEvaluator.cpp, footPrintNode/footPrintNode.cpp, footPrintNode_AnimatedMaterial/footPrintNode_GeometryOverride_AnimatedMaterial.cpp, footPrintNode_GeometryOverride/footPrintNode_GeometryOverride.cpp, identityNode/identityNode.cpp, nameFilter/NameFilter.cpp, nameFilter/NameFilter.h, offsetNode/offsetNode.cpp, rawfootPrintNode/rawfootPrintNode.cpp, simpleEvaluationDraw/simpleEvaluationDraw.cpp, simpleEvaluationNode/simpleEvaluationNode.cpp, simpleEvaluator/simpleEvaluator.cpp, simplePhysicsEngine/simplePhysicsEngine.cpp, simpleSimulationNode/simpleSimulationNode.cpp, simpleSkipNode/simpleSkipNode.cpp, testMTopologyEvaluator/testMTopologyEvaluator.cpp, and testMTopologyEvaluator/testMTopologyEvaluator.h.

Constructor & Destructor Documentation

MEvaluationNode ( const MEvaluationNode & evalNode )

default

Copy Constructor.

Parameters

[in] evalNode An existing evaluation node

Member Function Documentation

int parentCount ( ) const

Returns the number of parent nodes this evaluation node has.

Returns: The number of parent nodes this evauation node has.

Examples:: testMTopologyEvaluator/testMTopologyEvaluator.cpp.

MEvaluationNode parent ( int index ) const

Returns the parent node of this evaluation node at given index.

Parameters

[in] index Index of the parent evaluation node to access. No bound check is done so respect parentCount.

Returns: The MEvaluationNode parent object at given index.

Examples:: testMTopologyEvaluator/testMTopologyEvaluator.cpp.

int childCount ( ) const

Returns the number of children nodes this evaluation node has.

Returns: The number of children nodes this evauation node has.

Examples:: testMTopologyEvaluator/testMTopologyEvaluator.cpp.

MEvaluationNode child ( int index ) const

Returns the child node of this evaluation node at given index.

Parameters

[in] index Index of the child evaluation node to access. No bound check is done so respect childCount.

Returns: The MEvaluationNode child object at given index.

Examples:: testMTopologyEvaluator/testMTopologyEvaluator.cpp.

MEvaluationNodeIterator iterator ( MStatus * ReturnStatus = nullptr ) const

Returns an iterator at the beginning of the dirty plug list.

Parameters

[out] ReturnStatus Status Code

Returns: Iterator positioned at the beginning of the evaluation node's dirty plug list

Status Codes:

MS::kSuccess The operation succeeded
MS::kFailure Object error - no evaluation node

bool dirtyPlugExists	(	const MObject &	attribute,
		MStatus *	ReturnStatus = `nullptr`
	)		const

Returns true if the specified attribute has a dirty plug.

This call should be made from MPxNode::preEvaluation() and MPxNode::postEvaluation() to verify which plugs are going to be dirty and computed.

Note: Dirty plug is storing top-most array/parent of the plug tree in which given attribute exists. When a new computation starts with the evaluation manager, everything under a dirty plug is considered as dirty and will be computed.

Parameters

[in]	attribute	Attribute whose root plug is to be checked for membership in the dirty plug list
[out]	ReturnStatus	Status Code

Returns: True if the attribute exists in the dirty plug list, otherwise false.

Status Codes:

MS::kSuccess The operation succeeded
MS::kInvalidParameter MObject parameter is not an attribute
MS::kFailure Object error - no plug

Examples:: apiMeshShape/apiMeshShape.cpp, footPrintNode/footPrintNode.cpp, footPrintNode_AnimatedMaterial/footPrintNode_GeometryOverride_AnimatedMaterial.cpp, footPrintNode_GeometryOverride/footPrintNode_GeometryOverride.cpp, rawfootPrintNode/rawfootPrintNode.cpp, simpleEvaluationDraw/simpleEvaluationDraw.cpp, simpleEvaluationNode/simpleEvaluationNode.cpp, and simplePhysicsEngine/simplePhysicsEngine.cpp.

MPlug dirtyPlug	(	const MObject &	attribute,
		MStatus *	ReturnStatus = `nullptr`
	)		const

Returns the top-most plug for the specified attribute if the attribute has dirty plugs.

This call should be made from MPxNode::preEvaluation() and MPxNode::postEvaluation() to access a networked plug which is going to be dirty and computed.

Note: Dirty plug is storing top-most array/parent of the plug tree in which given attribute exists. When a new computation starts with the evaluation manager, everything under a dirty plug is considered as dirty and will be computed.

Parameters

[in]	attribute	Attribute whose root plug is returned if it is in the dirty plug list
[out]	ReturnStatus	Status Code

Returns: The top-most dirty plug for the specified attribute if it exists, a null plug otherwise.

Status Codes:

MS::kSuccess The operation succeeded
MS::kInvalidParameter MObject parameter is not an attribute
MS::kFailure Object error - no plug

MObject dependencyNode ( MStatus * ReturnStatus = nullptr ) const

Returns the dependency node this evaluation node represents.

Parameters

[out] ReturnStatus Status Code

Returns: The MObject representing the dependency node for this evaluation node.

Status Codes:

MS::kSuccess The operation succeeded
MS::kFailure Object error.

Examples:: constraintEvaluator/constraintEvaluator.cpp, evaluationPruningEvaluator/evaluationPruningEvaluator.cpp, nameFilter/NameFilter.cpp, and testMTopologyEvaluator/testMTopologyEvaluator.cpp.

MDataBlock datablock ( MStatus * ReturnStatus = nullptr ) const

Returns the datablock for this node.

Parameters

[out] ReturnStatus Status Code

Returns: The MDatablock representing the datablock for this evaluation node.

Status Codes:

MS::kSuccess The operation succeeded
MS::kFailure Object error.

Examples:: constraintEvaluator/constraintEvaluator.cpp, and testMTopologyEvaluator/testMTopologyEvaluator.cpp.

void connect	(	MEvaluationNode &	child,
		MStatus *	ReturnStatus = `nullptr`
	)

Connect two generic evaluation nodes.

Generic evaluation nodes are explicitly created by topology evaluators to override topology of base layer evaluation nodes claimed by topology cluster nodes.

Parameters

[in]	child	Generic evaluation node to connect as a child
[out]	ReturnStatus	Status Code

Status Codes:

MS::kSuccess Nodes were connected in evaluation graph
MS::kFailure Object error, trying to connect non-generic evaluation nodes

Examples:: testMTopologyEvaluator/testMTopologyEvaluator.cpp.

void skipEvaluation	(	const MObject &	attribute,
		bool	allowSingleDownstreamDependency = `false`,
		MStatus *	ReturnStatus = `nullptr`
	)		const

Hint the Evaluation Manager that the attribute can be skipped for the current evaluation.

This method tries to mark the attribute for the Evaluation Manager to skip its evaluation.

Attributes can be marked for their evaluation to be skipped if it's safe to do so. If the attribute is skipped, it will not be evaluated but will be left dirty so that subsequent pull evaluation will trigger evaluation and report the right value.

If the attribute is animated and driving more than one connected node, it is never safe to skip its evaluation, because the downstream nodes could trigger concurrent, and unsafe, pull evaluation. Therefore, this method does not have an effect if the attribute has more than one downstream dependency.

If the attribute has a single downstream dependency, it is potentially safe. Only a single node can pull on this attribute, but other nodes might be pulling on other attributes on the same node, which could result in a race condition. If the attribute is the only one skipped, the skipEvaluation method can allow a single connection through the allowSingleDownstreamDependency parameter.

If this attribute is not set, the skipEvaluation method will have the safest possible behavior of only skipping the evaluation if there are no downstream dependencies for the attribute to skip.

Note: This method should only be called from MPxNode::preEvaluation().; Skipping evaluation info is stored on the top-most array/parent of the plug tree in which given attribute exists. When skipping an attribute, everything under the top-most array/parent is what is actually considered for skipping.

Parameters

[in]	attribute	Attribute whose root plug is to be marked for skipping
[in]	allowSingleDownstreamDependency	True to allow one downstream dependency, false for the safest behavior of allowing none.
[out]	ReturnStatus	Status Code

Status Codes:

MS::kSuccess The operation succeeded. This does not guarantee the plug is marked for skipping.
MS::kInvalidParameter MObject parameter is not an attribute
MS::kFailure Object error - not the right type of evaluation node

Examples:: simpleSkipNode/simpleSkipNode.cpp.

bool skippingEvaluation	(	const MObject &	attribute,
		MStatus *	ReturnStatus = `nullptr`
	)		const

Returns true if the attribute was marked to be skipped.

Parameters

[in]	attribute	Attribute whose root plug is to be checked for skipping
[out]	ReturnStatus	Status Code

Status Codes:

MS::kSuccess The operation succeeded.
MS::kInvalidParameter MObject parameter is not an attribute
MS::kFailure Object error - not the right type of evaluation node

const char * className ( )

static

Returns the name of this class.

Returns: Name of this class.

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

MEvaluationNode.h
MEvaluationNode.cpp

Public Member Functions

Static Public Member Functions

Detailed Description

Constructor & Destructor Documentation

Member Function Documentation