Public Member Functions | Static Public Member Functions | Friends

MDGContext Class Reference

This reference page is linked to from the following overview topics: Appendix D: Frequently asked questions.


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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.

#include <MDGContext.h>

List of all members.

Public Member Functions

 MDGContext ()
 Constructor.
 MDGContext (const MTime &when)
 Constructor.
 MDGContext (const MDGContext &in)
 Copy constructor.
 ~MDGContext ()
 Destructor.
bool isNormal (MStatus *ReturnStatus=NULL) const
 Determines if this context is that of "normal" evaluation.
MStatus getTime (MTime &) const
 Return the single time for which this context is valid.
MDGContextoperator= (const MDGContext &other)
 Assignment operator.

Static Public Member Functions

static const char * className ()
 Returns the name of this class.

Friends

class MPlug
class MDataBlock

Constructor & Destructor Documentation

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 ( 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]atTimeThe time in which the evaluation will take place
MDGContext ( const MDGContext other)

Copy constructor.

Duplicates the given DG context.

Parameters:
[in]otherDG context to be copied.

Member Function Documentation

bool isNormal ( MStatus ReturnStatus = NULL) const

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

Parameters:
[out]ReturnStatusStatus code
Returns:
  • true this context is normal
  • false this context is not normal
Status Codes:
Examples:
rockingTransformCheck.cpp.
MStatus 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]timeValStorage for the time
Returns:
Status Code
Status Codes:
MDGContext & operator= ( const MDGContext other)

Assignment operator.

Copies the RHS into this context.

Parameters:
[in]otherDG context to be copied.
const char * className ( ) [static]

Returns the name of this class.

Returns:
Name of this class.

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