MPxFieldNode Class Reference

#include <MPxFieldNode.h>

Class Description

Base class for user defined fields.

MPxFieldNode allows the creation and manipulation of dependency graph nodes representing fields. This is the top level of a hierarchy of field node function sets. It permits manipulation of the attributes common to all types of fields.

Examples:

Inheritance diagram for MPxFieldNode:

Public Member Functions
	MPxFieldNode ()
	Class constructor.
virtual	~MPxFieldNode ()
	The class destructor.
virtual MPxNode::Type	type () const
	This method returns the type of the node. More...
virtual MStatus	compute (const MPlug &plug, MDataBlock &dataBlock)
	This method should be overridden in user defined nodes. More...
virtual MStatus	getForceAtPoint (const MVectorArray &point, const MVectorArray &velocity, const MDoubleArray &mass, MVectorArray &force, double deltaTime)
	This method is not required to be overridden, it is only necessary for compatibility with the MFnField function set. More...
virtual MStatus	iconSizeAndOrigin (GLuint &width, GLuint &height, GLuint &xbo, GLuint &ybo)
	Define the size and the origin of the field's icon. More...
virtual MStatus	iconBitmap (GLubyte *bitmap)
	Define the bitmap for the field's icon. More...
virtual void	draw (M3dView &view, const MDagPath &path, M3dView::DisplayStyle style, M3dView::DisplayStatus)
	Overriding this method allows the drawing of custom geometry using standard OpenGL calls. More...
virtual double	falloffCurve (const double param, MStatus *ReturnStatus=NULL)
	Returns the falloff at the given parameter value. More...
virtual bool	isFalloffCurveConstantOne (MStatus *ReturnStatus=NULL)
	Returns true if the falloffCurve is a constant one (default) or false if not. More...
Public Member Functions inherited from MPxNode
	MPxNode ()
	Constructor. More...
virtual	~MPxNode ()
	Destructor.
virtual void	postConstructor ()
	Post constructor. More...
virtual bool	getInternalValueInContext (const MPlug &plug, MDataHandle &dataHandle, MDGContext &ctx)
	This method is overridden by nodes that store attribute data in some internal format. More...
virtual bool	setInternalValueInContext (const MPlug &plug, const MDataHandle &dataHandle, MDGContext &ctx)
	This method is overridden by nodes that store attribute data in some internal format. More...
virtual bool	getInternalValue (const MPlug &plug, MDataHandle &dataHandle)
	This method is obsolete. More...
virtual bool	setInternalValue (const MPlug &plug, const MDataHandle &dataHandle)
	This method is obsolete. More...
virtual int	internalArrayCount (const MPlug &plug, const MDGContext &ctx) const
	This method is overridden by nodes that have internal array attributes which are not stored in Maya's datablock. More...
virtual void	copyInternalData (MPxNode *)
	This method is overridden by nodes that store attribute data in some internal format. More...
virtual MStatus	legalConnection (const MPlug &plug, const MPlug &otherPlug, bool asSrc, bool &isLegal) const
	This method allows you to check for legal connections being made to attributes of this node. More...
virtual MStatus	legalDisconnection (const MPlug &plug, const MPlug &otherPlug, bool asSrc, bool &isLegal) const
	This method allows you to check for legal disconnections being made to attributes of this node. More...
virtual MStatus	setDependentsDirty (const MPlug &plug, MPlugArray &plugArray)
	This method can be overridden in user defined nodes to specify which plugs should be set dirty based upon an input plug {plugBeingDirtied} which Maya is marking dirty. More...
virtual MStatus	preEvaluation (const MDGContext &context, const MEvaluationNode &evaluationNode)
	Prepare a node's internal state for threaded evaluation. More...
virtual MStatus	postEvaluation (const MDGContext &context, const MEvaluationNode &evaluationNode, PostEvaluationType evalType)
	Clean up node's internal state after threaded evaluation. More...
virtual SchedulingType	schedulingType () const
	When overridden this method controls the degree of parallelism supported by the node during threaded evaluation. More...
virtual MStatus	connectionMade (const MPlug &plug, const MPlug &otherPlug, bool asSrc)
	This method gets called when connections are made to attributes of this node. More...
virtual MStatus	connectionBroken (const MPlug &plug, const MPlug &otherPlug, bool asSrc)
	This method gets called when connections are broken with attributes of this node. More...
virtual MStatus	dependsOn (const MPlug &plug, const MPlug &otherPlug, bool &depends) const
	This method may be overridden by the user defined node. More...
virtual bool	isPassiveOutput (const MPlug &plug) const
	This method may be overridden by the user defined node if it wants to provide output attributes which do not prevent value modifications to the destination attribute. More...
virtual MStatus	shouldSave (const MPlug &plug, bool &isSaving)
	This method may be overridden by the user defined node. More...
virtual MPlug	passThroughToOne (const MPlug &plug) const
	This method may be overridden by nodes that have a one-to-one relationship between an input attribute and a corresponding output attribute. More...
virtual bool	passThroughToMany (const MPlug &plug, MPlugArray &plugArray) const
	This method is overridden by nodes that want to control the traversal behavior of some Maya search algorithms which traverse the history/future of shape nodes looking for directly related nodes. More...
virtual bool	isAbstractClass () const
	Override this class to return true if this node is an abstract node. More...
virtual MStringArray	getFilesToArchive (bool shortName=false, bool unresolvedName=false, bool markCouldBeImageSequence=false) const
	Use this method to return all external files used by this node. More...
virtual void	getExternalContent (MExternalContentInfoTable &table) const
	Returns the external content (files) that this node depends on. More...
bool	addExternalContentForFileAttr (MExternalContentInfoTable &table, const MObject &attr) const
	Adds content info to the specified table from a file path attribute. More...
bool	setExternalContentForFileAttr (const MObject &attr, const MExternalContentLocationTable &table)
	Sets content info in the specified attribute from the table. More...
virtual void	setExternalContent (const MExternalContentLocationTable &table)
	Changes the location of external content in batch. More...
virtual MTypeId	typeId () const
	Returns the TYPEID of this node. More...
virtual MString	typeName () const
	Returns the type name of this node. More...
virtual MString	name () const
	Returns the name of this particular instance of this class. More...
virtual MObject	thisMObject () const
	Returns the MObject associated with this user defined node. More...
virtual MStatus	setExistWithoutInConnections (bool flag)
	This method specifies whether or not the node can exist without input connections. More...
virtual bool	existWithoutInConnections (MStatus *ReturnStatus=NULL) const
	Determines whether or not this node can exist without input connections. More...
virtual MStatus	setExistWithoutOutConnections (bool flag)
	This method specifies whether or not the node can exist without output connections. More...
virtual bool	existWithoutOutConnections (MStatus *ReturnStatus=NULL) const
	Determines whether or not this node can exist without output connections. More...

Static Public Member Functions
static const char *	className ()
	Returns the name of this class. More...
Static Public Member Functions inherited from MPxNode
static MStatus	addAttribute (const MObject &attr)
	This method adds a new attribute to a user defined node type during the type's initialization. More...
static MStatus	inheritAttributesFrom (const MString &parentClassName)
	This method allows a class of plugin node to inherit all of the attributes of a second class of plugin node. More...
static MStatus	attributeAffects (const MObject &whenChanges, const MObject &isAffected)
	This method specifies that a particular input attribute affects a specific output attribute. More...
static const char *	className ()
	Returns the name of this class. More...

Static Public Attributes
static MObject	mMagnitude
	magnitude attribute
static MObject	mAttenuation
	attenuation attribute
static MObject	mMaxDistance
	maximum distance attribute
static MObject	mUseMaxDistance
	flag for maximum distance attribute
static MObject	mApplyPerVertex
	flag for per vertex attribute
static MObject	mInputData
	input attribute compound, multi
static MObject	mInputPositions
	child attribute, multi
static MObject	mInputVelocities
	child attribute, multi
static MObject	mInputMass
	child attribute, multi
static MObject	mDeltaTime
	child attribute
static MObject	mInputForce
	forces input attribute, multi
static MObject	mOutputForce
	forces output attribute, multi
static MObject	mOwnerCentroidX
	X component of mOwnerCentroid.
static MObject	mOwnerCentroidY
	Y component of mOwnerCentroid.
static MObject	mOwnerCentroidZ
	Z component of mOwnerCentroid.
static MObject	mOwnerCentroid
	owner centroid attribute
static MObject	mOwnerPosData
	owner position attribute, multi
static MObject	mOwnerVelData
	owner velocity attribute, multi
static MObject	mWorldMatrix
	world matrix attribute
static MObject	mInputPPData
	Attribute for input pp data from particleShape.
static MObject	mOwnerPPData
	Attribute for input pp data from owner particleShape.
Static Public Attributes inherited from MPxNode
static MObject	message
	message attribute
static MObject	isHistoricallyInteresting
	is historically interesting attribute
static MObject	caching
	caching attribute
static MObject	state
	state attribute
static MObject	frozen
	frozen attribute

Additional Inherited Members
Public Types inherited from MPxNode
enum	Type {   kDependNode, kLocatorNode, kDeformerNode, kManipContainer,   kSurfaceShape, kFieldNode, kEmitterNode, kSpringNode,   kIkSolverNode, kHardwareShader, kHwShaderNode, kTransformNode,   kObjectSet, kFluidEmitterNode, kImagePlaneNode, kParticleAttributeMapperNode,   kCameraSetNode, kConstraintNode, kManipulatorNode, kMotionPathNode,   kClientDeviceNode, kThreadedDeviceNode, kAssembly, kSkinCluster,   kGeometryFilter, kBlendShape, kLast }
	Defines the type of node. More...
enum	SchedulingType {   kParallel, kSerial, kGloballySerial, kUntrusted,   kDefaultScheduling = kSerial }
	Defines the degree of parallelism of a node. More...
Protected Member Functions inherited from MPxNode
virtual MDataBlock	forceCache (MDGContext &ctx=MDGContext::fsNormal)
	USE _forceCache() IN SCRIPT. More...
virtual void	setMPSafe (bool flag)
	USE _setMPSafe() IN SCRIPT. More...
virtual MStatus	setDoNotWrite (bool flag)
	USE _setDoNotWrite() IN SCRIPT. More...
virtual bool	doNotWrite (MStatus *ReturnStatus=NULL) const
	USE _doNotWrite() IN SCRIPT. More...

Member Function Documentation

MPxNode::Type type ( ) const

virtual

This method returns the type of the node.

This method should not be overridden by the user. It will return MPxNode::kFieldNode.

Returns

The type of node

Status Codes:

• MS::kSuccess The undo was successful
• MS::kFailure This method is not undoable

Reimplemented from MPxNode.

MStatus compute ( const MPlug &  plug, MDataBlock &  dataBlock  )

virtual

This method should be overridden in user defined nodes.

Recompute the given output based on the nodes inputs. The plug represents the data value that needs to be recomputed, and the data block holds the storage for all of the node's attributes.

The MDataBlock will provide smart handles for reading and writing this node's attribute values. Only these values should be used when performing computations.

When evaluating the dependency graph, Maya will first call the compute method for this node. If the plug that is provided to the compute indicates that that the attribute was defined by the Maya parent node, the compute method should return MS::kUnknownParameter. When this occurs, Maya will call the internal Maya node from which the user-defined node is derived to compute the plug's value.

This means that a user defined node does not need to be concerned with computing inherited output attributes. However, if desired, these can be safely recomputed by this method to change the behaviour of the node.

Parameters

[in]	plug	plug representing the attribute that needs to be recomputed
[in]	dataBlock	data block containing storage for the node's attributes

Returns

Status code

Status Codes:

• MS::kSuccess Compute was successful
• MS::kFailure Compute failed

Reimplemented from MPxNode.

Examples:

MStatus getForceAtPoint ( const MVectorArray &  point, const MVectorArray &  velocity, const MDoubleArray &  mass, MVectorArray &  force, double  deltaTime  )

virtual

This method is not required to be overridden, it is only necessary for compatibility with the MFnField function set.

Compute the force of a field on an array of points, given their position, velocity, and mass.

This method uses MVectorArray to represent the positions of a point.

Parameters

[in]	point	array of positions for each point.
[in]	velocity	array of velocities for each point. If the length of the velocity array is 0, a velocity of 0.0 is assumed for all the points. Note the velocity array is a requirement for the Air and Drag fields to compute forces.
[in]	mass	array of mass values for each point. If the length of the mass array is 0, a mass of 1.0 is assumed for all the points.
[out]	force	output array of forces applied to each point. If the length of the force array supplied is 0, the array is automatically resized. If the contents of the force array contains data, the computed force is added to the supplied data. This can be useful to accumulate forces of multiple fields.
[in]	deltaTime	time increment in seconds

Returns

Status code

Status Codes:

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

Examples:

MStatus iconSizeAndOrigin ( GLuint &  width, GLuint &  height, GLuint &  xbo, GLuint &  ybo  )

virtual

Define the size and the origin of the field's icon.

Maya calls this method to determine the size and origin of the icon you wish your field to use. Overriding this method is optional.

The arguments have the same meaning as defined in OpenGL's glBitmap method.

Parameters

[out]	width	the width of the icon in pixels. It needs to be a multiple of 32 on windows and a multiple of 16 on any other platform.
[out]	height	the height of the icon in pixels. It needs to be a multiple of 32 on windows and a multiple of 16 on any other platform.
[out]	xbo	the origin of the icon in x direction.
[out]	ybo	the origin of the icon in y direction.

Returns

Status code

Status Codes:

• MS::kSuccess has custom icon.
• MS::kFailure no custom icon.

Examples:

MStatus iconBitmap ( GLubyte *  bitmap )

virtual

Define the bitmap for the field's icon.

Maya calls this method to get the bitmap for the icon you wish your field to use. Overriding this method is optional, but if you do override it then you must also override iconSizeAndOrigin().

Parameters

[out]

bitmap

Bitmap for the field's icon, in the format expected by OpenGL's glBitmap() function. The storage pointed to by this parameter will have already been allocated by Maya according to the values returned by iconSizeAndOrigin().

Returns

Status code

Status Codes:

• MS::kSuccess has custom icon.
• MS::kFailure no custom icon.

Examples:

void draw ( M3dView &  view, const MDagPath &  path, M3dView::DisplayStyle  style, M3dView::DisplayStatus    )

virtual

Overriding this method allows the drawing of custom geometry using standard OpenGL calls.

The OpenGL state should be left in the same state that it was in previously. The OpenGL routine glPushAttrib may be used to make this easier.

When this routine is called, the following conditions may be assumed:

• the correct transform matrix will be loaded for the node, so the geometry should be drawn in local space
• the correct default color will be set for wire frame drawing given the object's state (eg active, dormant, etc.)
• the object is not invisible or hidden
• if the object has a bounding box, then the bounding box is at least partially in the frustum

As a convenience, this draw method will also be used by OpenGL's selection mechanism to determine whether this object gets selected by a particular mouse event. The user does not need to write a separate selection routine.

Parameters

[in]	view	3D view that is being drawn into
[in]	path	to this node in the DAG
[in]	style	style to draw object in

Examples:

double falloffCurve ( const double  param, MStatus *  ReturnStatus = NULL  )

virtual

Returns the falloff at the given parameter value.

Parameters

[in]	param	Parameter value in the range [0.0, 1.0]
[out]	ReturnStatus	Status code

Returns

The falloff value at the given the param.

Status Codes:

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

bool isFalloffCurveConstantOne ( MStatus *  ReturnStatus = NULL )

virtual

Returns true if the falloffCurve is a constant one (default) or false if not.

Parameters

[out]

ReturnStatus

Status code

Returns

true if the falloff curve is a constant one, false otherwise

Status Codes:

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

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:

• MPxFieldNode.h
• MPxFieldNode.cpp