class MPxDeformerNode

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Inheritance:

MPxDeformerNode < MPxNode

public members:

	MPxDeformerNode ()
virtual	~MPxDeformerNode ()
virtual MPxNode::Type	type () const
virtual MStatus	deform ( MDataBlock & block, MItGeometry & iter, const MMatrix & mat, unsigned int multiIndex)
virtual MObject &	accessoryAttribute () const
virtual MStatus	accessoryNodeSetup ( MDagModifier & cmd)
float	weightValue ( MDataBlock & mblock, unsigned int multiIndex, unsigned int wtIndex)
void	setUseExistingConnectionWhenSetEditing (bool state)
virtual void	setModifiedCallback ( MSelectionList & list, bool listAdded )
static MObject	input input attribute, multi
static MObject	inputGeom input geometry attribute
static MObject	groupId input group id attribute
static MObject	outputGeom geometry output attribute
static MObject	weightList weight list attribute, multi
static MObject	weights weight attribute, multi
static MObject	envelope envelope attribute

Inherited from MPxNode:

public members:

enum	Type kDependNode kLocatorNode kDeformerNode kManipContainer kSurfaceShape kFieldNode kEmitterNode kSpringNode kIkSolverNode kHardwareShader Custom shader derived from MPxHardwareShader kHwShaderNode Custom shader derived from MPxHwShaderNode kTransformNode kObjectSet kFluidEmitterNode kImagePlaneNode kParticleAttributeMapperNode kConstraintNode kLast
virtual void	postConstructor ()
virtual MStatus	compute ( const MPlug & plug, MDataBlock & dataBlock )
virtual bool	getInternalValueInContext ( const MPlug & plug, MDataHandle & dataHandle, MDGContext & ctx)
virtual bool	setInternalValueInContext ( const MPlug & plug, const MDataHandle & dataHandle, MDGContext & ctx)
virtual bool	getInternalValue ( const MPlug & plug, MDataHandle & dataHandle)
virtual bool	setInternalValue ( const MPlug & plug, const MDataHandle & dataHandle)
virtual int	internalArrayCount ( const MPlug & plug, const MDGContext & ctx) const
virtual void	copyInternalData ( MPxNode * )
virtual MStatus	legalConnection ( const MPlug & plug, const MPlug & otherPlug, bool asSrc, bool& isLegal ) const
virtual MStatus	legalDisconnection ( const MPlug & plug, const MPlug & otherPlug, bool asSrc, bool& isLegal ) const
virtual MStatus	setDependentsDirty ( const MPlug & plug, MPlugArray & plugArray)
virtual MStatus	connectionMade ( const MPlug & plug, const MPlug & otherPlug, bool asSrc )
virtual MStatus	connectionBroken ( const MPlug & plug, const MPlug & otherPlug, bool asSrc )
virtual bool	isPassiveOutput ( const MPlug & plug ) const
virtual MStatus	shouldSave ( const MPlug & plug, bool& isSaving )
virtual MPlug	passThroughToOne ( const MPlug & plug ) const
virtual bool	passThroughToMany ( const MPlug & plug, MPlugArray & plugArray ) const
MTypeId	typeId () const
MString	typeName () const
MString	name () const
virtual Type	type () const
virtual bool	isAbstractClass () const
MObject	thisMObject () const
static MStatus	addAttribute ( const MObject & attr )
static MStatus	inheritAttributesFrom ( const MString & parentClassName )
static MStatus	attributeAffects ( const MObject & whenChanges, const MObject & isAffected )
MStatus	setExistWithoutInConnections ( bool flag )
bool	existWithoutInConnections ( MStatus * ReturnStatus = NULL ) const
MStatus	setExistWithoutOutConnections ( bool flag )
bool	existWithoutOutConnections ( MStatus * ReturnStatus = NULL ) const
static MObject	message
static MObject	isHistoricallyInteresting
static MObject	caching
static MObject	state

protected members:

MDataBlock	forceCache ( MDGContext & ctx= MDGContext::fsNormal )
void	setMPSafe ( bool flag )
MStatus	setDoNotWrite ( bool flag )
bool	doNotWrite ( MStatus *ReturnStatus = NULL ) const

Documentation

Description

MPxDeformerNode allows the creation of user-defined deformers. A deformer is a node which takes any number of input geometries, deforms them, and places the output into the output geometry attribute.

If you write a deformer by deriving from MPxDeformerNode, your deformer will derive the benefit of Maya's internal deformer functionality, namely:

• The Set Editing Tool and the Set Editor Window can be used to modify the membership of the deformer.
• Association of a weight value with each CV. The weight values can be modified by the user using the set editing window or the percent command. This weight value can be used or ignored at the plugin's discretion.
• "Has No Effect" mode is implemented in the base class, and disables the node.
• When the deformer node is deleted, its inputs and outputs will be correctly reconnected in the dependency graph.
• Reordering of the deformer node with other deformers via the Complete List window.
• Placement and connection of the deformer node in the dependency graph via the "deformer -type" command. The deformer command also has the standard deformer options such as exclusive membership and parallel mode.

Deformers are full dependency nodes and can have attributes and a deform() method. In general, to derive the full benefit of the Maya deformer base class, it is suggested that you do not write your own compute() method. Instead, write the deform() method, which is called by the MPxDeformerNode's compute() method. However, there are some exceptions when you would instead write your own compute(), namely:

• Your node's deformation algorithm depends on the geometry type, which is not available in the deform() method.
• Your node's deformation algorithm requires computing all of the output geometries simultaneously.

In the case where you cannot simply override the deform() method, the following example code shows one possible compute() method implementation. This compute() example creates an iterator for the deformer set corresponding to the output geometry being computed. Note that this sample compute() implementation does not do any deformation, and does not implement handling of the nodeState attribute. If you do choose to override compute() in your node, there is no reason to implement the deform() method, since it will not be called by the base class.

MStatus
exampleDeformer::compute(const MPlug& plug, MDataBlock& dataBlock)
{
    MStatus status = MS::kUnknownParameter;
 	if (plug.attribute() == outputGeom) {
		// get the input corresponding to this output
		//
		unsigned int index = plug.logicalIndex();
		MObject thisNode = this->thisMObject();
		MPlug inPlug(thisNode,input);
		inPlug.selectAncestorLogicalIndex(index,input);
		MDataHandle hInput = dataBlock.inputValue(inPlug);

		// get the input geometry and input groupId
		//
		MDataHandle hGeom = hInput.child(inputGeom);
		MDataHandle hGroup = hInput.child(groupId);
		unsigned int groupId = hGroup.asLong();
		MDataHandle hOutput = dataBlock.outputValue(plug);
		hOutput.copy(hGeom);

		// do the deformation
		//
		MItGeometry iter(hOutput,groupId,false);
		for ( ; !iter.isDone(); iter.next()) {
			MPoint pt = iter.position();

			//
            // insert deformation code here
			//
			
			iter.setPosition(pt);
		}
		status = MS::kSuccess;
	}
	return status;
}

For most deformers, implementing compute() is unnecessary. To create a deformer, derive from this class and override the deform() method as demonstrated in the "offsetNode.cpp" example plug-in. The other methods of the parent class MPxNode may also be overridden to perform standard dependency node capabilities.

When implementing the compute method for a deformer, another consideration is that the input geometry attribute is not cached. This means that all of the inputs will evaluate each time MDataBlock::inputArrayValue is called on "inputGeom". If you only want a single inputGeometry, you can prevent unneeded evaluations by avoiding calls to MDataBlock.inputArrayValue. For example, use the technique shown in the above example or use MDataBlock::outputArrayValue.

Functions

MPxDeformerNode:: MPxDeformerNode ()

Constructor

Class constructor.

MPxDeformerNode:: ~MPxDeformerNode ()

Destructor

Class destructor.

MPxNode::Type MPxDeformerNode:: type () const

Description

This method returns the type of the node. This method should not be overridden by the user. It will return MPxNode::kDeformerNode.

Return Value

• the type of node

MStatus MPxDeformerNode:: deform ( MDataBlock & block, MItGeometry & iterator, const MMatrix & matrix, unsigned int multiIndex)

Description

This method performs the deformation algorithm. A status code of MS::kSuccess should be returned unless there was a problem during the deformation, such as insufficient memory or required input data is missing or invalid.

NOTE: the geometry iterator passed to this method is in local space and not world space. To convert points to world space use the matrix that is suppied.

Arguments

• block the node's datablock.
• iterator an iterator for the current geometry being deformed.
• matrix the geometry's world space transformation matrix.
• multiIndex the index corresponding to the requested output geometry.

Return Value

• status code

Status Codes

• MS::kSuccess The method was successful.
• MS::kFailure An object error has occurred.

MObject & MPxDeformerNode:: accessoryAttribute () const

Description

This method returns an MObject for the attribute to which an accessory shape is connected. If the accessory shape is deleted, the deformer node will automatically be deleted.

If your node has no associated shape, there is no need to override this method.

Return Value

• the accessory attribute

MStatus MPxDeformerNode:: accessoryNodeSetup ( MDagModifier & cmd)

Description

This method is called by the "deformer -type" command when your node is specified.

This method can be used to create and attach accessory nodes if your plugin node requires them. To do so, override this method, and provide the creation and attachment commands to the MDagModifier that is passed as input to the method.

If your node has no associated nodes, there is no need to override this method.

Arguments

• cmd the dag modifier to which the method will add commands

Return Value

• status code

float MPxDeformerNode:: weightValue ( MDataBlock & block, unsigned int multiIndex, unsigned int wtIndex)

Description

This method returns the weightValue stored in the datablock for the given geometry's lattice point/CV/vertex.

Arguments

• block the datablock for the node
• multiIndex the index corresponding to the geometry
• wtIndex the index corresponding to the component

Return Value

• weight

void MPxDeformerNode:: setUseExistingConnectionWhenSetEditing (bool state)

Description

This method allows the plugin node to request special treatment during set editing. It controls the connection behavior if all of a geometry's points are removed from the deformer set, and then points are subsequently added back in to the set again. By default, Maya will reconnect the deformer to the shape using a new input/output index. If this method is called in the custom deformer's postConstructor method and the state is set to true, the deformer will attempt to use the original input/output index when reconnecting to the shape.

Arguments

• state whether or not to use the existing connection

void MPxDeformerNode:: setModifiedCallback ( MSelectionList & list, bool listAdded)

Description

This callback method can be overriden and is called whenever the set this deformer is operating on is modified. It passes in a selection list of items that are either being added/removed.

Arguments

• list list of items added/removed
• list whether the list is being added or removed to the set.

This class has no child classes.