MItDag Class Reference
 
 
 

This reference page is linked to from the following overview topics: Querying the Scene Graph, Flags, DAG walking example.


#include <MItDag.h>


Class Description

DAG Iterator.

Use the DAG iterator to traverse the DAG either depth first or breadth first, visiting each node and, if desired, retrieving the node (as an MObject). The DAG iterator provides a basic filtering capability, so that DAG node retrieval can be limited to a specific type (MFn::Type) of node. With filtering enabled the iterator checks to see if the node is compatible with the type of Function Set specified by the filter. See MFn::Type for a list of all valid Function set types.

Since each object, if retrieved, is returned as an MObject, the MObject::hasFn() method can be used to further check for compatible function set types since an MObjects may be compatible with more than one function set).

Any compatible Function Set can be attached to the retrieved object to query or or edit it. Often you will want to use the DAG node Function Set (MFnDagNode), which is compatible with all DAG objects, to perform basic queries on each node as the iterator traverses the DAG.

The iterator also provides the capability to reset the root of the iteration, the type of traversal, and the filter.

Additionally, the iterator can be queried for the root, mode and type of traversal, and to determine if the the traversal has been completed.

Examples:

AbcExport/AbcWriteJob.cpp, AbcExport/MayaNurbsCurveWriter.cpp, animExportUtil/animExportUtil.cpp, animInfoCmd/animInfoCmd.cpp, atomImportExport/atomFileUtils.cpp, D3DViewportRenderer/D3DResourceManager.cpp, D3DViewportRenderer/D3DViewportRenderer.cpp, DX11ViewportRenderer/DX11ViewportRenderer.cpp, exampleCameraSetView/exampleCameraSetViewCmd.cpp, gpuCache/gpuCacheSubSceneOverride.cpp, lepTranslator/lepTranslator.cpp, maTranslator/maTranslator.cpp, narrowPolyViewer/narrowPolyViewerCmd.cpp, objExport/objExport.cpp, OpenGLViewportRenderer/OpenGLViewportRenderer.cpp, polyRawExporter/polyExporter.cpp, polyX3DExporter/polyExporter.cpp, scanDagCmd/scanDagCmd.cpp, scanDagSyntax/scanDagSyntax.cpp, viewObjectFilter/viewObjectFilter.cpp, and xmlAssembly/AssemblyExporter.cpp.

List of all members.

Public Types

enum   TraversalType { kInvalidType = 0, kDepthFirst, kBreadthFirst }
  Order in which nodes should be traversed. More...

Public Member Functions

  MItDag (TraversalType=kDepthFirst, MFn::Type=MFn::kInvalid, MStatus *ReturnStatus=NULL)
  Class Constructor.
  MItDag (MIteratorType &dagInfoObject, TraversalType=kDepthFirst, MStatus *ReturnStatus=NULL)
  Class Constructor.
MStatus  reset ()
  Resets the iterator.
MStatus  reset (const MObject &object, TraversalType=kDepthFirst, MFn::Type=MFn::kInvalid)
  Resets root, type and filter of the iterator.
MStatus  reset (const MDagPath &path, TraversalType=kDepthFirst, MFn::Type=MFn::kInvalid)
  Resets root, type and filter of the iterator.
MStatus  reset (MIteratorType &dagInfoObject, const MObject *object, const MDagPath *path, TraversalType=kDepthFirst)
  Resets root, type and filter list of the iterator.
MObject  item (MStatus *ReturnStatus=NULL)
  This method is obsolete.
MObject  currentItem (MStatus *ReturnStatus=NULL)
  Retrieves DAG node to which the iterator points.
MStatus  next ()
  Moves to the next node matching the filter in the graph.
MStatus  prune ()
  Prunes iteration tree at current node.
bool  isDone (MStatus *ReturnStatus=NULL) const
  Indicates end of iteration path.
MObject  root (MStatus *ReturnStatus=NULL)
  Returns the root (start node) of the current traversal.
unsigned int  depth (MStatus *ReturnStatus=NULL) const
  Returns the height or depth of the current node in the DAG relative to the root node.
TraversalType  getType (MStatus *ReturnStatus=NULL) const
  Returns the direction of the traversal.
MStatus  getPath (MDagPath &path) const
  Determines a DAG Path to the current item in the iteration.
MStatus  getAllPaths (MDagPathArray &paths) const
  Determines all DAG Paths to current item in the iteration.
MString  fullPathName (MStatus *ReturnStatus=NULL) const
  Return a string representing the full path from the root of the dag to this object.
MString  partialPathName (MStatus *ReturnStatus=NULL) const
  Return a string representing the partial path from the root of the dag to this object.
bool  isInstanced (bool indirect=true, MStatus *ReturnStatus=NULL) const
  Determines whether the current item (DAG node) in the iteration is directly or indirectly instanced.
unsigned int  instanceCount (bool total, MStatus *ReturnStatus=NULL) const
  Determines the number of times the current item (DAG node) in the iteration is instanced.
MStatus  traverseUnderWorld (bool flag)
  Specifies whether underworld traversal is turned on.
bool  willTraverseUnderWorld (MStatus *ReturnStatus=NULL) const
  Returns true if this iterator will traverse into underworld items.
virtual  ~MItDag ()
  Class Destructor.

Static Public Member Functions

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

Member Enumeration Documentation

Order in which nodes should be traversed.

Enumerator:
kInvalidType 

 

kDepthFirst 

Visit a node's children before moving on to its siblings.

kBreadthFirst 

Visit a node's siblings before moving on to its children.


Constructor & Destructor Documentation

MItDag ( MItDag::TraversalType  type = kDepthFirst,
MFn::Type  filter = MFn::kInvalid,
MStatus ReturnStatus = NULL 
)

Class Constructor.

Initializes the root of iteration at the world node, sets the type of the traversal, and the filter. Sets a return status parameter to indicate success or failure.

Parameters:
[in] type Enumerated type that determines the direction of the traversal
  • kDepthFirst - Traverse vertically first
  • kBreadthFirst - Traverse horizontally first
Parameters:
[in] filter Function set type (MFn::Type)
  • kInvalid - Filtering disabled
  • See MFn::Type for other values
Parameters:
[out] ReturnStatus Status Code (see below)
Status Codes:
  • MS::kSuccess Success
  • MS::kInvlaidParameter Invalid parameter passed for mode or type
  • MS::kFailure Failure creating iterator
MItDag ( MIteratorType dagInfoObject,
MItDag::TraversalType  type = kDepthFirst,
MStatus ReturnStatus = NULL 
)

Class Constructor.

Initializes the root of iteration at the world node, sets the type of the traversal, and the filter list. Sets a return status parameter to indicate success or failure.

Parameters:
[in] type Enumerated type that determines the direction of the traversal
  • kDepthFirst - Traverse vertically first
  • kBreadthFirst - Traverse horizontally first
Parameters:
[in] dagInfoObject Object which has details of type_filter or filter list.
[out] ReturnStatus Status Code (see below)
Status Codes:
  • MS::kSuccess Success
  • MS::kInvlaidParameter Invalid parameter passed for mode or type
  • MS::kFailure Failure creating iterator
~MItDag ( ) [virtual]

Class Destructor.

Deletes iterator.


Member Function Documentation

MStatus reset ( )

Resets the iterator.

The iterator is reset to the previous traversal setting.

Returns:
Status code
Status Codes:
Examples:
AbcExport/AbcWriteJob.cpp, AbcExport/MayaNurbsCurveWriter.cpp, and gpuCache/gpuCacheSubSceneOverride.cpp.
MStatus reset ( const MObject object,
MItDag::TraversalType  type = kDepthFirst,
MFn::Type  filter = MFn::kInvalid 
)

Resets root, type and filter of the iterator.

Parameters:
[in] object Root node to begin traversal
[in] type Enumerated type that determines the direction of the traversal
  • kDepthFirst - Traverse vertically first
  • kBreadthFirst - Traverse horizontally first
Parameters:
[in] filter Function set type (MFn::Type)
  • kInvalid - Filtering disabled
  • See MFn::Type for other values
Returns:
Status code
Status Codes:
MStatus reset ( const MDagPath path,
MItDag::TraversalType  type = kDepthFirst,
MFn::Type  filter = MFn::kInvalid 
)

Resets root, type and filter of the iterator.

This method is usefull when a node is instanced and a DAG path is necessary to specify which instance should be the root of the traversal.

Parameters:
[in] path Path to begin traversal
[in] type Enumerated type that determines the direction of the traversal
  • kInvalid - Invalid parameter. Not used.
  • kDepthFirst - Traverse vertically first
Parameters:
[in] filter Function set type (MFn::Type)
  • kInvalid - Filtering disabled
  • See MFn::Type for other values
Returns:
Status code
Status Codes:
  • MS::kSuccess Success
  • MS::kInvlaidParameter Invalid parameter passed for object, mode or type
  • MS::kFailure Failure resetting iterator
MStatus reset ( MIteratorType dagInfoObject,
const MObject object,
const MDagPath path,
MItDag::TraversalType  type = kDepthFirst 
)

Resets root, type and filter list of the iterator.

This method is usefull when a node is instanced and a DAG path is necessary to specify which instance should be the root of the traversal.

Parameters:
[in] dagInfoObject Iterator object having info on filter or filterlist.
[in] object MObject, to which the iterator will be reset to. This may be NULL if we are setting the iterator root to dagpath object.
[in] path MDagPath object, to which the iterator will be reset to. This may be NULL if we are setting the iterator root to MObject.
[in] type Enumerated type that determines the direction of the traversal
  • kInvalid - Invalid parameter. Not used.
  • kDepthFirst - Traverse vertically first
Returns:
Status code
Status Codes:
  • MS::kSuccess Success
  • MS::kInvlaidParameter Invalid parameter passed for object, mode or type
  • MS::kFailure Failure resetting iterator
MObject item ( MStatus ReturnStatus = NULL )

This method is obsolete.

Deprecated:
Use the MItDag::currentItem method instead.

Retrieves DAG node to which the iterator points.

Parameters:
[out] ReturnStatus Status Code (see below).
Returns:
Pointer to the DAG node. Null pointer indicates failure.
Status Codes:
Examples:
maTranslator/maTranslator.cpp.
MObject currentItem ( MStatus ReturnStatus = NULL )

Retrieves DAG node to which the iterator points.

Parameters:
[out] ReturnStatus Status Code (see below).
Returns:
Pointer to the DAG node. Null pointer indicates failure.
Status Codes:
Examples:
AbcExport/AbcWriteJob.cpp, and gpuCache/gpuCacheSubSceneOverride.cpp.
MStatus next ( )

Moves to the next node matching the filter in the graph.

Returns:
Status code
Status Codes:
Examples:
AbcExport/AbcWriteJob.cpp, AbcExport/MayaNurbsCurveWriter.cpp, gpuCache/gpuCacheSubSceneOverride.cpp, and maTranslator/maTranslator.cpp.
MStatus prune ( )

Prunes iteration tree at current node.

Returns:
Status code
Status Codes:
Examples:
AbcExport/AbcWriteJob.cpp, and maTranslator/maTranslator.cpp.
bool isDone ( MStatus ReturnStatus = NULL ) const

Indicates end of iteration path.

Parameters:
[out] ReturnStatus Status Code (see below)
Returns:
Boolean value: true when done, false otherwise.
Status Codes:
Examples:
AbcExport/AbcWriteJob.cpp, AbcExport/MayaNurbsCurveWriter.cpp, gpuCache/gpuCacheSubSceneOverride.cpp, and maTranslator/maTranslator.cpp.
MObject root ( MStatus ReturnStatus = NULL )

Returns the root (start node) of the current traversal.

The constructor sets the root of traversal to the world node. The root can be changed by the reset() method.

Parameters:
[out] ReturnStatus Status Code (see below)
Returns:
Root of the traversal
Status Codes:
unsigned int depth ( MStatus ReturnStatus = NULL ) const

Returns the height or depth of the current node in the DAG relative to the root node.

The root node has a depth of zero.

Parameters:
[out] ReturnStatus Status Code (see below)
Returns:
Depth of the current node
Status Codes:
MItDag::TraversalType getType ( MStatus ReturnStatus = NULL ) const

Returns the direction of the traversal.

Parameters:
[out] ReturnStatus Status Code (see below)
Returns:
  • kDepthFirst Recursively visits grandchildren of each child node
  • kBreadthFirst Recursively visits each child/parent node before any grandchild/grandparent nodes
Status Codes:
MStatus getPath ( MDagPath path ) const

Determines a DAG Path to the current item in the iteration.

Parameters:
[out] path The DAG Path that is found (implicit return)
Returns:
Status Code
Status Codes:
Examples:
AbcExport/AbcWriteJob.cpp, AbcExport/MayaNurbsCurveWriter.cpp, and maTranslator/maTranslator.cpp.
MStatus getAllPaths ( MDagPathArray paths ) const

Determines all DAG Paths to current item in the iteration.

Parameters:
[out] paths Array of all DAG Paths that are found (implicit return)
Returns:
Status Code
Status Codes:
MString fullPathName ( MStatus ReturnStatus = NULL ) const

Return a string representing the full path from the root of the dag to this object.

Parameters:
[out] ReturnStatus Status Code (see below)
Returns:
The full path name
Status Codes:
Examples:
gpuCache/gpuCacheSubSceneOverride.cpp.
MString partialPathName ( MStatus ReturnStatus = NULL ) const

Return a string representing the partial path from the root of the dag to this object.

The partial path is the minimum path that is still unique. This string may contain wildcards.

Parameters:
[out] ReturnStatus Status Code (see below)
Returns:
The partial path name
Status Codes:
bool isInstanced ( bool  indirect = true,
MStatus ReturnStatus = NULL 
) const

Determines whether the current item (DAG node) in the iteration is directly or indirectly instanced.

If indirect instance flag is false, the result is true if and only if the Node itself is multiply instanced (node->parentCount > 1).

If the indirect flag is true, the result is true if and only if the Node itself is multiply instanced (node->parentCount > 1) or if the Node is not multipuly instanced, but it has a directly instanced parent (node->parentCount()=1 and parent->parentCount >1).

Parameters:
[in] indirect Indirect instance flag
[out] ReturnStatus Status Code (see below)
Returns:
  • true = Node is instanced (directly or indirectly according to indirect instance flag)
  • false = Node is not instanced (directly or indirectly according to indirect instance flag)
Status Codes:
unsigned int instanceCount ( bool  total,
MStatus ReturnStatus = NULL 
) const

Determines the number of times the current item (DAG node) in the iteration is instanced.

If total is false the number of direct instances is returned, which is the same as the node's parent count.

If total is true the total number of instances is returned, including indirect instances resulting from instancing higher up the DAG hierarchy (i.e. one or more of the node's ancestors also has multiple instances).

Parameters:
[in] total Controls whether to include indirect instances in the count.
[out] ReturnStatus Status Code (see below)
Returns:
Number of instances.
Status Codes:
MStatus traverseUnderWorld ( bool  flag )

Specifies whether underworld traversal is turned on.

The default is off.

The underworld for a shape is a sub dag that hangs off of the shape. For example, if you have a curve on surface for a shape then there will be an underworld or sub-dag for the curve on surface.

Parameters:
[in] flag turns on/off underworld traversal
Returns:
Status Code
Status Codes:
Examples:
maTranslator/maTranslator.cpp.
bool willTraverseUnderWorld ( MStatus ReturnStatus = NULL ) const

Returns true if this iterator will traverse into underworld items.

The underworld for a shape is a sub dag that hangs off of the shape. For example, if you have a curve on surface for a shape then there will be an underworld or sub-dag for the curve on surface.

Parameters:
[out] ReturnStatus Status Code (see below)
Returns:
Boolean: true if underworld traversal is on, false otherwise.
Status Codes:
const char * className ( ) [static]

Returns the name of this class.

Returns:
The name of this class.

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