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

#include <MDataBlock.h>

List of all members.


Detailed Description

Dependency node data block.

An MDataBlock provides storage for the data being received by or sent by the node. It is the data for the plugs and attributes of the node. The data block is only valid during the compute method of the depend node. Pointers to the data block should not be retained after the compute method.

Access to the data in an MDataBlock is done using an MDataHandle or an MArrayDataHandle.

Examples:

affectsNode.cpp, animCubeNode.cpp, anisotropicShader.cpp, apiMeshCreator.cpp, apiMeshCreator.h, apiMeshShape.cpp, apiMeshShape.h, arcLenNode.cpp, backfillShader.cpp, blindDataMesh.cpp, blindDataMesh.h, blindDataShader.cpp, blindDataShader.h, brickShader.cpp, buildRotationNode.cpp, cellShader.cpp, cgfxShaderNode.cpp, cgfxShaderNode.h, cgfxVector.cpp, cgfxVector.h, checkerShader.cpp, circleNode.cpp, clearcoat.cpp, closestPointOnCurveNode.cpp, closestPointOnCurveNode.h, compositingShader.cpp, contrastShader.cpp, curvedArrowsNode.cpp, cvColorNode.cpp, cvColorShader.cpp, depthShader.cpp, displacementShader.cpp, dynExprField.cpp, dynExprField.h, exampleMRampAttribute.cpp, flameShader.cpp, footPrintManip.cpp, footPrintNode.cpp, fullLoftNode.cpp, gammaShader.cpp, genericAttributeNode.cpp, geometrySurfaceConstraint.cpp, geometrySurfaceConstraint.h, geomShader.cpp, GLSLShaderNode.cpp, GLSLShaderNode.h, hwColorPerVertexShader.cpp, hwDecalBumpShader_NV20.cpp, hwDecalBumpShader_NV20.h, hwPhongShader.cpp, hwPhongShader.h, hwReflectBumpShader_NV20.cpp, hwReflectBumpShader_NV20.h, hwRefractReflectShader_NV20.cpp, hwRefractReflectShader_NV20.h, hwToonShader_NV20.cpp, hwToonShader_NV20.h, hwUnlitShader.cpp, hwUnlitShader.h, interpShader.cpp, jitterNode.cpp, lambertShader.cpp, latticeNoise.h, latticeNoiseNode.cpp, lavaShader.cpp, lightShader.cpp, meshOpNode.cpp, meshOpNode.h, mixtureShader.cpp, multiCurveNode.cpp, noiseShader.cpp, offsetNode.cpp, ownerEmitter.cpp, ownerEmitter.h, particleAttrNode.cpp, particleAttrNode.h, phongShader.cpp, pointOnMeshInfoNode.cpp, pointOnMeshInfoNode.h, pointOnSubdNode.cpp, pointOnSubdNode.h, polyTrgNode.cpp, quadricShape.cpp, renderAccessNode.cpp, rockingTransform.cpp, rockingTransformCheck.cpp, rockingTransformCheck.h, shadowMatteShader.cpp, shellNode.cpp, shiftNode.cpp, simpleEmitter.cpp, simpleEmitter.h, simpleFluidEmitter.cpp, simpleFluidEmitter.h, simpleLoftNode.cpp, simpleSpring.cpp, simpleSpring.h, sineNode.cpp, slopeShaderNode.cpp, slopeShaderNode.h, solidCheckerShader.cpp, splitUVNode.cpp, splitUVNode.h, stringFormatNode.cpp, sweptEmitter.cpp, sweptEmitter.h, swissArmyManip.cpp, testNobjectNode.cpp, testNobjectNode.h, testNucleusNode.cpp, testNucleusNode.h, torusField.cpp, torusField.h, transCircleNode.cpp, volumeShader.cpp, weightListNode.cpp, and yTwistNode.cpp.


Public Member Functions

virtual  ~MDataBlock ()
MDataHandle  inputValue (const MPlug &plug, MStatus *ReturnStatus=NULL)
MDataHandle  inputValue (const MObject &attribute, MStatus *ReturnStatus=NULL)
MDataHandle  outputValue (const MPlug &plug, MStatus *ReturnStatus=NULL)
MDataHandle  outputValue (const MObject &attribute, MStatus *ReturnStatus=NULL)
MArrayDataHandle  inputArrayValue (const MPlug &plug, MStatus *ReturnStatus=NULL)
MArrayDataHandle  inputArrayValue (const MObject &attribute, MStatus *ReturnStatus=NULL)
MArrayDataHandle  outputArrayValue (const MPlug &plug, MStatus *ReturnStatus=NULL)
MArrayDataHandle  outputArrayValue (const MObject &attribute, MStatus *ReturnStatus=NULL)
MStatus  setClean (const MPlug &plug)
MStatus  setClean (const MObject &attribute)
bool  isClean (const MPlug &plug)
bool  isClean (const MObject &attribute, MStatus *ReturnStatus=NULL)
MDGContext  context (MStatus *ReturnStatus=NULL)
MStatus  setContext (const MDGContext &ctx)

Friends

class  MArrayDataBuilder
class  MPxNode
class  MPlug

Constructor & Destructor Documentation

MDataBlock::~MDataBlock (  )  [virtual]

The class destructor.


Member Function Documentation

MDataHandle MDataBlock::inputValue ( const MPlug plug,
MStatus ReturnStatus = NULL  
)

Gets a handle to this data block for the given plug's data. The data represented by the handle is guaranteed to be valid for reading. If the data is from a dirty connection, then the connection will be evaluated. If no connection is present, then the value that the plug has been set to will be returned. If the plug has not been set to a particular value, then the default value will be returned.

Parameters:
[in]  plug  the plug whose data you wish to access
[out]  ReturnStatus  the return status
Returns:
Data handle for the given plug's data
Status Codes:
Examples:

MDataHandle MDataBlock::inputValue ( const MObject attribute,
MStatus ReturnStatus = NULL  
)

Gets a handle to this data block for the given plug's data. The data represented by the handle is guaranteed to be valid for reading. If the data is from a dirty connection, then the connection will be evaluated. If no connection is present, then the value that the plug has been set to will be returned. If the plug has not been set to a particular value, then the default value will be returned.

Parameters:
[in]  attribute  the attribute of the node that you want to access
[out]  ReturnStatus  the return status
Returns:
Data handle for the given attributes's data
Status Codes:

MDataHandle MDataBlock::outputValue ( const MPlug plug,
MStatus ReturnStatus = NULL  
)

Gets a handle to this data block for the given attributes's data. The data is not guaranteed to be valid. No dependency graph evaluations will be done. Therefore, this handle should be used only for writing.

Parameters:
[in]  plug  the plug whose data you wish to access
[out]  ReturnStatus  the return status
Returns:
Data handle for the given plug's data
Status Codes:
Examples:

MDataHandle MDataBlock::outputValue ( const MObject attribute,
MStatus ReturnStatus = NULL  
)

Gets a handle to this data block for the given attributes's data. The data is not guaranteed to be valid. No dependency graph evaluations will be done. Therefore, this handle should be used only for writing.

Parameters:
[in]  attribute  the attribute of the node that you want to access
[out]  ReturnStatus  the return status
Returns:
Data handle for the given attribute's data
Status Codes:

MArrayDataHandle MDataBlock::inputArrayValue ( const MPlug plug,
MStatus ReturnStatus = NULL  
)

Gets an array handle to this data block for the given plug's data. This is only valid if the given plug has array data. The data represented by the handle will be valid. If the data is from a dirty connection, then the connection will be evaluated. If no connection is present, then the value that the plug has been set to will be returned. If the plug has not been set to a particular value, then the default value will be returned.

Parameters:
[in]  plug  the plug whose data you wish to access
[out]  ReturnStatus  the return status
Returns:
Array data handle for the given attributes's data
Status Codes:
Examples:

MArrayDataHandle MDataBlock::inputArrayValue ( const MObject attribute,
MStatus ReturnStatus = NULL  
)

Gets an array handle to this data block for the given plug's data. This is only valid if the given plug has array data. The data represented by the handle will be valid. If the data is from a dirty connection, then the connection will be evaluated. If no connection is present, then the value that the plug has been set to will be returned. If the plug has not been set to a particular value, then the default value will be returned.

Parameters:
[in]  attribute  The attribute whose data you wish to access
[out]  ReturnStatus  The return status
Returns:
Array data handle for the given attributes's data
Status Codes:

MArrayDataHandle MDataBlock::outputArrayValue ( const MPlug plug,
MStatus ReturnStatus = NULL  
)

Gets a handle to this data block for the given plug. No dependency graph evaluations will be done, and therefore the data is not guaranteed to be valid (i.e. it may be dirty). Typically, this method is used to get the handle during compute in order to write output data to it.

Another usage of this method is to access an input array attribute without evaluating any of its array elements. One can then use MArrayDataHandle::jumpToElement to get to the particular element of interest, and evaluate its value using MArrayDataHandle::inputValue.

Parameters:
[in]  plug  the plug whose data you wish to access
[out]  ReturnStatus  the return status
Returns:
Array data handle for the given plug's data
Status Codes:
Examples:

MArrayDataHandle MDataBlock::outputArrayValue ( const MObject attribute,
MStatus ReturnStatus = NULL  
)

Gets a handle to this data block for the given attributes's data. The data is not guaranteed to be valid. No dependency graph evaluations will be done. Therefore, this handle should be used only for writing.

Parameters:
[in]  attribute  the attribute of the node that you want to access
[out]  ReturnStatus  the return status
Returns:
Array data handle for the given attribute's data
Status Codes:

MStatus MDataBlock::setClean ( const MPlug plug  ) 

Tells the dependency graph that the given plug has been updated and is now clean. This should be called after the data in the plug has been recalculated from the inputs of the node.

Parameters:
[in]  plug  the plug that is to be marked clean
Returns:
Result status code
Status Codes:
Examples:

MStatus MDataBlock::setClean ( const MObject attribute  ) 

Tells the dependency graph that the given attribute has been updated and is now clean. This should be called after the data in the plug has been recalculated from the inputs of the node.

Parameters:
[in]  attribute  the attribute that we have updated the data for
Returns:
Result status code
Status Codes:

bool MDataBlock::isClean ( const MPlug plug  ) 

Queries the dependency graph to see whether the given plug is clean.

Parameters:
[in]  plug  the plug that is to be query
Returns:
Result boolean code, true if plug is clean, false otherwise.

bool MDataBlock::isClean ( const MObject attribute,
MStatus ReturnStatus = NULL  
)

Queries the dependency graph to see whether the given attribute is clean.

Parameters:
[in]  attribute  The attribute to query.
[out]  ReturnStatus  Status code.
Returns:
true if the attribute is clean, false otherwise.
Status Codes:

MDGContext MDataBlock::context ( MStatus ReturnStatus = NULL  ) 

Returns a copy of the dependecy graph context for which this data block was created. The context is used to specify how a dependency node is going to be evaluated.

Parameters:
[out]  ReturnStatus  Status code
Returns:
The dependency graph context
Status Codes:
Examples:

MStatus MDataBlock::setContext ( const MDGContext ctx  ) 

Set the dependency graph context for this data block. The context is used to specify how a dependency node is going to be evaluated, thus replacing the context for the given datablock. This does not modify the dirty state of the datablock so that they apply to the new context.

This function should not be used for timed evaluation.

Parameters:
[in]  ctx  the dependency graph context
Returns:
Status code
Status Codes:

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