C++ API Reference
Public Member Functions | Static Public Member Functions | List of all members
MArrayDataHandle Class Reference
OpenMaya - API module for common classes

Data block handle for array data. More...

#include <MArrayDataHandle.h>

Public Member Functions

 MArrayDataHandle (const MDataHandle &in, MStatus *ReturnStatus=NULL)
 Copy constructor. More...
 
MDataHandle inputValue (MStatus *ReturnStatus=NULL)
 Gets a handle into this data block for the current array element. More...
 
MDataHandle outputValue (MStatus *ReturnStatus=NULL)
 Gets a handle into this data block for the current array element. More...
 
MArrayDataHandle inputArrayValue (MStatus *ReturnStatus=NULL)
 Gets a handle into this data block for the current array element. More...
 
MArrayDataHandle outputArrayValue (MStatus *ReturnStatus=NULL)
 Gets a handle into this data block for the current array element. More...
 
MStatus next ()
 Advance to the next element in the array. More...
 
unsigned int elementCount (MStatus *ReturnStatus=NULL)
 Returns the number of elements in the array. More...
 
unsigned int elementIndex (MStatus *ReturnStatus=NULL)
 Returns the index that we are currently at in the array. More...
 
MStatus jumpToElement (unsigned int index)
 Jump to a specific element in the array. More...
 
MStatus jumpToArrayElement (unsigned int position)
 Jump to a specific array element in the array. More...
 
MStatus setClean ()
 Marks the data that is represented by this handle as being clean. More...
 
MStatus setAllClean ()
 Marks every element of the array attribute represented by the handle as clean. More...
 
MArrayDataBuilder builder (MStatus *ReturnStatus=NULL)
 Returns a builder for this handle's array so that it can be expanded. More...
 
MStatus set (MArrayDataBuilder &builder)
 Sets the data for this array from the data in the builder object. More...
 
 MArrayDataHandle (const MArrayDataHandle &other)
 Copy constructor. More...
 
MArrayDataHandle & operator= (const MArrayDataHandle &other)
 Assignment operator. More...
 

Static Public Member Functions

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

Detailed Description

Data block handle for array data.

An MArrayDataHandle is a smart pointer into a data block (MDataBlock) that handles access to array data. MArrayDataHandle supports attributes that can have an array of data.

The array indices do not have to be continuous. The array can be sparse. Thus, an array could have four elements with the indicies 1, 6, 8, and 10.

MArrayDataHandle methods cannot be assumed to be threadsafe. The jumpToElement() method sets an internal pointer so definitely cannot be called by multiple threads simultaneously.

Examples:
AbcImport/AlembicNode.cpp, anisotropicShader/anisotropicShader.cpp, apiMeshShape/apiMeshShape.cpp, apiMeshShape/apiMeshShape.h, backfillShader/backfillShader.cpp, basicBlendShape/basicBlendShape.cpp, basicSkinCluster/basicSkinCluster.cpp, constraintEvaluator/constraintEvaluator.cpp, dynExprField/dynExprField.cpp, footPrintNode/footPrintNode.cpp, fullLoftNode/fullLoftNode.cpp, geometrySurfaceConstraint/geometrySurfaceConstraint.cpp, lambertShader/lambertShader.cpp, multiCurveNode/multiCurveNode.cpp, multiPlugInfoCmd/multiPlugInfoCmd.cpp, offsetNode/offsetNode.cpp, onbShader/onbShader.cpp, ownerEmitter/ownerEmitter.cpp, ownerEmitter/ownerEmitter.h, phongShader/phongShader.cpp, shadowMatteShader/shadowMatteShader.cpp, simpleEmitter/simpleEmitter.cpp, simpleEmitter/simpleEmitter.h, splatDeformer/splatDeformer.cpp, sseDeformer/sseDeformer.cpp, stringFormatNode/stringFormatNode.cpp, sweptEmitter/sweptEmitter.cpp, sweptEmitter/sweptEmitter.h, testNsolverNode/testNsolverNode.cpp, testNucleusNode/testNucleusNode.cpp, torusField/torusField.cpp, and weightListNode/weightListNode.cpp.

Constructor & Destructor Documentation

OPENMAYA_MAJOR_NAMESPACE_OPEN MArrayDataHandle ( const MDataHandle &  in,
MStatus *  ReturnStatus = NULL 
)

Copy constructor.

Creates an new array data handle from the specified data handle.

This method can be used to access an array attribute that is a child of a compound array. Example: weightList[].weights[]

This method will only work for data handles to attributes that are arrays.

Parameters
[in]inHandle to the child array attribute.
[out]ReturnStatusreturn status
Status Codes:
  • kSuccess operation successful
  • kInvalidParameter source handle is null or is not an array
MArrayDataHandle ( const MArrayDataHandle &  other)
inline

Copy constructor.

Parameters
[in]otherthe source object to copy from.

Member Function Documentation

MDataHandle inputValue ( MStatus *  ReturnStatus = NULL)

Gets a handle into this data block for the current array element.

The data represented by the handle will be valid. If the data is from an dirty connection, then the connection will be evaluated.

It is important to note that you can not call inputValue on an element that is greater than the elementCount in this arrayDataHandle. That is, calls to inputValue must be protected by a call to elementCount to ensure the element exists. If this is not done, the call to inputValue will fail with an invalidParameter error.

The data handle that this arrayDataHandle represents must come from a valid data block, such as one returned from one of the MDataBlock methods like MDataBlock::inputValue(). If a data handle created and returned from MPlug::getValue() or MPlug::asMDataHandle() is passed to this arrayDataHandle, then the use of this method will be invalid as it cannot legally trigger evaluation. See MArrayDataHandle::outputValue() instead.

Parameters
[out]ReturnStatusreturn status
Returns
Data handle for the current element's data
Status Codes:
  • kSuccess operation successful
  • kInvalidParameter the requested element is out of range
  • kFailure an object error has occurred
Examples:
anisotropicShader/anisotropicShader.cpp, backfillShader/backfillShader.cpp, basicBlendShape/basicBlendShape.cpp, basicSkinCluster/basicSkinCluster.cpp, constraintEvaluator/constraintEvaluator.cpp, dynExprField/dynExprField.cpp, fullLoftNode/fullLoftNode.cpp, geometrySurfaceConstraint/geometrySurfaceConstraint.cpp, lambertShader/lambertShader.cpp, offsetNode/offsetNode.cpp, onbShader/onbShader.cpp, ownerEmitter/ownerEmitter.h, phongShader/phongShader.cpp, shadowMatteShader/shadowMatteShader.cpp, simpleEmitter/simpleEmitter.h, splatDeformer/splatDeformer.cpp, sseDeformer/sseDeformer.cpp, stringFormatNode/stringFormatNode.cpp, sweptEmitter/sweptEmitter.h, testNsolverNode/testNsolverNode.cpp, testNucleusNode/testNucleusNode.cpp, and torusField/torusField.cpp.
MDataHandle outputValue ( MStatus *  ReturnStatus = NULL)

Gets a handle into this data block for the current array element.

The data is not guaranteed to be valid. Therefore, this handle should only be used for writing over the data.

This method can also be used to retrieve handles to individual elements of non-datablock array handles, such as those returned by MPlug::getValue() and MPlug::asMDataHandle().

Parameters
[out]ReturnStatusreturn status
Returns
Data handle for the current element's data
Status Codes:
  • kSuccess operation successful
  • kFailure an object error has occurred
Examples:
AbcImport/AlembicNode.cpp, apiMeshShape/apiMeshShape.cpp, and weightListNode/weightListNode.cpp.
MArrayDataHandle inputArrayValue ( MStatus *  ReturnStatus = NULL)

Gets a handle into this data block for the current array element.

This method should be used when the array elements are also arrays. The data represented by the handle will be valid. If the data is from an dirty connection, then the connection will be evailuated.

It is important to note that you can not call inputArrayValue on an element that is greater than the elementCount in this arrayDataHandle. That is, calls to inputValue must be protected by a call to elementCount to ensure the element exists. If this is not done, the the call to inputArrayValue will fail with an invalidParameter error.

The data handle that this arrayDataHandle represents must come from a valid data block, such as one returned from one of the MDataBlock methods like MDataBlock::inputValue(). If a data handle created and returned from MPlug::getValue() or MPlug::asMDataHandle() is passed to this arrayDataHandle, then the use of this method will be invalid as it cannot legally trigger evaluation. See MArrayDataHandle::outputValue() instead.

Parameters
[out]ReturnStatusreturn status
Returns
Data handle for the current element's data
Status Codes:
  • kSuccess operation successful
  • kInvalidParameter the current item is not an array or the requested element is out of range.
  • kFailure an object error has occurred
Examples:
apiMeshShape/apiMeshShape.cpp.
MArrayDataHandle outputArrayValue ( MStatus *  ReturnStatus = NULL)

Gets a handle into this data block for the current array element.

This method should be used when the array elements are also arrays. The data is not guaranteed to be valid. Therefore, this handle should only be used for writing over the data.

The data handle that this arrayDataHandle represents must come from a valid data block, such as one returned from one of the MDataBlock methods like MDataBlock::inputValue(). If a data handle created and returned from MPlug::getValue() or MPlug::asMDataHandle() is passed to this arrayDataHandle, then the use of this method will be invalid as it cannot legally trigger evaluation. See MArrayDataHandle::outputValue() instead.

Parameters
[out]ReturnStatusreturn status
Returns
Data handle for the current element's data
Status Codes:
  • kSuccess operation successful
  • kInvalidParameter the current item is not an array
  • kFailure an object error has occurred
MStatus next ( )

Advance to the next element in the array.

These may be sparse arrays so the next consecutive element may not necessarily have a consecutive index.

Returns
  • MS::kSuccess if there was a next element
  • MS::kFailure if the object is invalid or there is no next element
Examples:
AbcImport/AlembicNode.cpp, anisotropicShader/anisotropicShader.cpp, apiMeshShape/apiMeshShape.cpp, backfillShader/backfillShader.cpp, basicBlendShape/basicBlendShape.cpp, basicSkinCluster/basicSkinCluster.cpp, fullLoftNode/fullLoftNode.cpp, geometrySurfaceConstraint/geometrySurfaceConstraint.cpp, lambertShader/lambertShader.cpp, offsetNode/offsetNode.cpp, onbShader/onbShader.cpp, phongShader/phongShader.cpp, shadowMatteShader/shadowMatteShader.cpp, splatDeformer/splatDeformer.cpp, and sseDeformer/sseDeformer.cpp.
unsigned int elementCount ( MStatus *  ReturnStatus = NULL)

Returns the number of elements in the array.

Parameters
[out]ReturnStatusreturn status
Returns
The number of elements
Status Codes:
  • kSuccess operation successful
  • kFailure an object error has occurred
Examples:
AbcImport/AlembicNode.cpp, anisotropicShader/anisotropicShader.cpp, backfillShader/backfillShader.cpp, basicBlendShape/basicBlendShape.cpp, basicSkinCluster/basicSkinCluster.cpp, constraintEvaluator/constraintEvaluator.cpp, fullLoftNode/fullLoftNode.cpp, geometrySurfaceConstraint/geometrySurfaceConstraint.cpp, lambertShader/lambertShader.cpp, offsetNode/offsetNode.cpp, onbShader/onbShader.cpp, phongShader/phongShader.cpp, shadowMatteShader/shadowMatteShader.cpp, testNsolverNode/testNsolverNode.cpp, and weightListNode/weightListNode.cpp.
unsigned int elementIndex ( MStatus *  ReturnStatus = NULL)

Returns the index that we are currently at in the array.

It is possible for the index to be invalid, in which case the return status will report an error. These may be sparse arrays so the element index returned will be a logical index.

Parameters
[out]ReturnStatusreturn status
Returns
The current element's logical index
Status Codes:
  • kSuccess operation successful
  • kFailure current element has an invalid index, or this function set has an invalid object
Examples:
AbcImport/AlembicNode.cpp, apiMeshShape/apiMeshShape.cpp, offsetNode/offsetNode.cpp, splatDeformer/splatDeformer.cpp, and sseDeformer/sseDeformer.cpp.
MStatus jumpToElement ( unsigned int  index)

Jump to a specific element in the array.

The array is sparse, so the indices may not be consecutive.

NOTE: The index is the logical element index, which may be sparse.

Jumping to an element is done through a binary search, with heuristics that improve the starting point for the search for simpler cases, such as:

  • where the elements are contiguous (or at least mostly contiguous), or
  • if you ask for the element that immediately follows the previously searched result.

In those cases the search will be more likely to find the right spot in one or two guesses instead of always needing to search over the entire range. The algorithm is therefore still O(logn) in the worst case (as a typical binary search), but it should average closer to O(1) if the dataset is not very sparse and if it is being searched iteratively, in order.

Parameters
[in]indexthe logical index to jump to
Returns
Status code
Status Codes:
  • MS::kSuccess the operation was successful
  • MS::kInvalidParameter the given index does not exist
  • kFailure an object error has occurred
Examples:
basicBlendShape/basicBlendShape.cpp, basicSkinCluster/basicSkinCluster.cpp, constraintEvaluator/constraintEvaluator.cpp, dynExprField/dynExprField.cpp, fullLoftNode/fullLoftNode.cpp, offsetNode/offsetNode.cpp, ownerEmitter/ownerEmitter.h, simpleEmitter/simpleEmitter.h, stringFormatNode/stringFormatNode.cpp, sweptEmitter/sweptEmitter.h, testNsolverNode/testNsolverNode.cpp, testNucleusNode/testNucleusNode.cpp, torusField/torusField.cpp, and weightListNode/weightListNode.cpp.
MStatus jumpToArrayElement ( unsigned int  position)

Jump to a specific array element in the array.

This method can be used to iterate over the entire array.

NOTE: Jumping to an array element does not require a search, since the array indices are non-sparse. The MArrayDataHandle::elementIndex() method can be used to determine the logical index related to the current array index.

Parameters
[in]positionthe array position to jump to
Returns
Status code
Status Codes:
  • MS::kSuccess the operation was successful
  • MS::kInvalidParameter the given array element does not exist
  • kFailure an object error has occurred
Examples:
basicBlendShape/basicBlendShape.cpp, splatDeformer/splatDeformer.cpp, sseDeformer/sseDeformer.cpp, and weightListNode/weightListNode.cpp.
MStatus setClean ( )

Marks the data that is represented by this handle as being clean.

This should be done after recalculating the data from the inputs.

The data handle that this arrayDataHandle represents must come from a valid data block, such as one returned from one of the MDataBlock methods like MDataBlock::inputValue(). If a data handle created and returned from MPlug::getValue() or MPlug::asMDataHandle() is passed to this arrayDataHandle, then the use of this method will be invalid.

Returns
Return status
Status Codes:
  • kSuccess operation successful
  • kFailure an object error has occurred
MStatus setAllClean ( )

Marks every element of the array attribute represented by the handle as clean.

This method should be used if a compute function is asked to compute a single element of a multi, but instead calculates all the elements. Calling setAllClean in this situation will prevent further calls to the node's compute method for the other elements of the multi.

The data handle that this arrayDataHandle represents must come from a valid data block, such as one returned from one of the MDataBlock methods like MDataBlock::inputValue(). If a data handle created and returned from MPlug::getValue() or MPlug::asMDataHandle() is passed to this arrayDataHandle, then the use of this method will be invalid.

Returns
Return status
Status Codes:
  • kSuccess operation successful
  • kFailure an object error has occurred
Examples:
AbcImport/AlembicNode.cpp, apiMeshShape/apiMeshShape.cpp, footPrintNode/footPrintNode.cpp, and multiCurveNode/multiCurveNode.cpp.
MArrayDataBuilder builder ( MStatus *  ReturnStatus = NULL)

Returns a builder for this handle's array so that it can be expanded.

This method will fail if the current array does not support array data builders. This can be changed in a node's initialize routine using the setUsesArrayDataBuilder method in MFnAttribute.

The data handle that this arrayDataHandle represents must come from a valid data block, such as one returned from one of the MDataBlock methods like MDataBlock::inputValue(). If a data handle created and returned from MPlug::getValue() or MPlug::asMDataHandle() is passed to this arrayDataHandle, then the use of this method will be invalid.

Parameters
[out]ReturnStatusreturn status
Returns
The builder object
Status Codes:
  • kSuccess operation successful
  • kInvalidParameter This item does not support array data builders
  • kFailure an object error has occurred
Examples:
apiMeshShape/apiMeshShape.cpp, ownerEmitter/ownerEmitter.cpp, simpleEmitter/simpleEmitter.cpp, sweptEmitter/sweptEmitter.cpp, and torusField/torusField.cpp.
MStatus set ( MArrayDataBuilder &  builder)

Sets the data for this array from the data in the builder object.

The data handle that this arrayDataHandle represents must come from a valid data block, such as one returned from one of the MDataBlock methods like MDataBlock::inputValue(). If a data handle created and returned from MPlug::getValue() or MPlug::asMDataHandle() is passed to this arrayDataHandle, then the use of this method will be invalid.

Parameters
[in]builderthe builder object
Returns
Return status
Status Codes:
  • kSuccess operation successful
  • kInvalidParameter the builder passed is invalid
  • kFailure an object error has occurred
Examples:
apiMeshShape/apiMeshShape.cpp, and multiCurveNode/multiCurveNode.cpp.
MArrayDataHandle & operator= ( const MArrayDataHandle &  other)
inline

Assignment operator.

Parameters
[in]otherthe source object to copy from.
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: