MDGContext Class Reference
[OpenMaya - API module for common classes]

#include <MDGContext.h>

Collaboration diagram for MDGContext:

[legend]

List of all members.

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Detailed Description

Dependency graph (DG) context class.

Control the way in which dependency nodes are evaluated.

DG contexts are used to define the way in which a dependency node is going to be evaluated. Examples of such contexts include "normal", "at a given time, "for a specific instance", etc.

MDGContext is mainly used in two places; within methods that trigger evaluations, to define what kind of evaluate is being requested, and within data blocks (MDataBlock), to identify how the data was created.

Examples:

cgfxShaderNode.cpp, cgfxShaderNode.h, customImagePlane.cpp, GLSLShaderNode.cpp, GLSLShaderNode.h, hlslShader.cpp, hlslShader.h, hwColorPerVertexShader.cpp, hwPhongShader.cpp, hwPhongShader.h, rockingTransform.cpp, rockingTransform.h, and rockingTransformCheck.cpp.

Public Member Functions
	MDGContext ()
	MDGContext (const MTime &when)
	MDGContext (const MDGContext &in)
	~MDGContext ()
bool	isNormal (MStatus *ReturnStatus=NULL) const
MStatus	getTime (MTime &) const
MDGContext &	operator= (const MDGContext &other)
Friends
class	MPlug
class	MDataBlock

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Constructor & Destructor Documentation

MDGContext::MDGContext

(

)

Constructor. Creates a context to define the way in which a dependency node is evaluated. In this case the new context will be for a normal evaluation.

MDGContext::MDGContext

(

const MTime &

atTime

)

Constructor. Creates a context to define the way in which a dependency node is evaluated. In this case the new context will be for an evaluation at a specific time.

Parameters:

[in]

atTime

The time in which the evaluation will take place

MDGContext::MDGContext

(

const MDGContext &

other

)

Copy constructor. Duplicates the given DG context.

Parameters:

[in]

other

DG context to be copied.

MDGContext::~MDGContext

(

)

Destructor.

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Member Function Documentation

bool MDGContext::isNormal

(

MStatus *

ReturnStatus = NULL

)

const

Determines if this context is that of "normal" evaluation.

Parameters:

[out]

ReturnStatus

Status code

Returns:

• true this context is normal
• false this context is not normal

Status Codes:

• MS::kSuccess Method was successful
• MS::kFailure Object error

Examples:

rockingTransformCheck.cpp.

MStatus MDGContext::getTime

(

MTime &

timeVal

)

const

Return the single time for which this context is valid. The context must be a timed context, i.e. not a normal one.

Parameters:

[out]

timeVal

Storage for the time

Returns:

Status Code

Status Codes:

• MS::kSuccess The time was successfully returned
• MS::kFailure Context is not timed

MDGContext & MDGContext::operator=

(

const MDGContext &

other

)

Assignment operator. Copies the RHS into this context.

Parameters:

[in]

other

DG context to be copied.