MEvaluationNode Class Reference

#include <MEvaluationNode.h>

Class Description

Provides access to Evaluation Manager node information.

See also

MEvaluationNodeIterator

An evaluation node is an object that is placed within an evaluation graph. 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:

Public Member Functions
	~MEvaluationNode ()
	Destructor.
	MEvaluationNode (const MEvaluationNode &evalNode)
	Copy Constructor. More...
MEvaluationNodeIterator	iterator (MStatus *ReturnStatus=NULL) const
	Returns an iterator at the beginning of the dirty plug list. More...
bool	dirtyPlugExists (const MObject &attribute, MStatus *ReturnStatus=NULL) const
	Returns true if the specified attribute has a dirty plug. More...
MPlug	dirtyPlug (const MObject &attribute, MStatus *ReturnStatus=NULL) const
	Returns the top-most plug for the specified attribute if the attribute has dirty plugs. More...

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

Friends
class	MEvaluationNodeIterator
class	MGraphNodeIterator

Constructor & Destructor Documentation

MEvaluationNode

(

const MEvaluationNode &

evalNode

)

Copy Constructor.

Parameters

[in]

evalNode

An existing evaluation node

Member Function Documentation

MEvaluationNodeIterator iterator

(

MStatus *

ReturnStatus = NULL

)

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 = NULL
	)		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:

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

const char * className ( )

static

Returns the name of this class.

Returns

Name of this class.

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

• MEvaluationNode.h
• MEvaluationNode.cpp