#include <MPxPolyTrg.h>

Class Description

User defined poly triangulation support.

MPxPolyTrg is the the parent class for nodes which define a custom face triangulation for meshes. In order to override default maya triangulation, the user has to do the following things:

Derive a new node from MPxPolyTrg class.
Define a static function on the new node to triangulate a single face in the mesh. The signature of this function is given by polyTrgFnct type. The input to the triangulation function is:
- *vert - pointer to an array of vertex positions for the face. It size is 3*nbVertices.
- *norm - pointer to an array of per vertex normals for the face. It size is 3*nbVertices.
- *loopSizes - pointer to an array of loop sizes. The size of this array is nbLoops
- nbLoops - number of loops in the face.
- nbTrg - expected number of triangles to be generated.
Note: The number of vertices can be calculated by adding all the loop sizes.

The output of this function is an array of triangle description:
- *trg - pointer to an integer array. This array is already allocated with the size of 3*nbTrg. It has to be filled with the triangle descriptions given by the face-relative position of vertices i.e.
  
  nbTrg = 2 trg: 0 1 2 2 3 0
  
  Tip: Refer to the example plugin: polyTrgNode for more details on how to implement it.
Register that function when the node is created for the first time (in the postConstructor() method) by calling the registerTrgFunction().
Unregister the function in the destructor by calling the unregisterTrgFunction.

Once the node is defined, the user has to inform the mesh about it. For each mesh the user wants to override the default triangulation, he has to set the usertTrg attribute on the mesh to the name under which the function has been registered.

Example: /code setAttr mesh.userTrg -type "string" "triangulate"; /endcode

Once that attribute is set, the default maya triangulation is turned off and the one provided by the user is used to draw the mesh.

Examples:: polyTrgNode/polyTrgNode.cpp.

Inheritance diagram for MPxPolyTrg:

Public Types
typedef void(*	polyTrgFnct) (const float vert, const float norm, const int loopSizes, const int nbLoop, const int nbTrg, unsigned short trg)
	Pointer to a function which triangulates a poly face.

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...

Public Member Functions
	MPxPolyTrg ()
	Constructor. More...

virtual	~MPxPolyTrg ()
	Destructor.

virtual void	postConstructor ()
	Post constructor. More...

virtual MStatus	compute (const MPlug &plug, MDataBlock &dataBlock)
	This method should be overridden in user defined nodes. More...

virtual bool	isAbstractClass () const
	Each new node has to implement that fuction. More...

MStatus	registerTrgFunction (char *name, polyTrgFnct f)
	Register a triangulation function with maya. More...

MStatus	unregisterTrgFunction (char *name)

Public Member Functions inherited from MPxNode
	MPxNode ()
	Constructor. More...

virtual	~MPxNode ()
	Destructor.

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 Type	type () const
	Returns the type of node that this is. 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...

Additional Inherited Members
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 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

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...

Constructor & Destructor Documentation

MPxPolyTrg ( )

Constructor.

The constructor should never call any methods from MPxPolyTrg or make any calls that require the existence of the MObject associated with the user defined node. The postConstructor method should be used to do any initialization of this kind.

Member Function Documentation

void postConstructor ( )

virtual

Post constructor.

Internally maya creates two objects when a user defined node is created, the internal MObject and the user derived object. The association between the these two objects is not made until after the MPxPolyTrg constructor is called. This implies that no MPxPolyTrg member function can be called from the MPxPolyTrg constructor. The postConstructor will get called immediately after the constructor when it is safe to call any MPxPolyTrg member function.

Reimplemented from MPxNode.

Examples:: polyTrgNode/polyTrgNode.cpp.

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

virtual

This method should be overridden in user defined nodes.

However, fror this particaular node we don't need to to do anything in the compute functione. Therefore, all we do is return MS:kSuccess in the derive class.

Parameters

[in]	plug	plug representing the attribute that needs to be recomputed
[in]	block	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:: polyTrgNode/polyTrgNode.cpp.

bool isAbstractClass ( ) const

virtual

Each new node has to implement that fuction.

It returns false since this is not an abstract class.

Returns: False

Reimplemented from MPxNode.

Examples:: polyTrgNode/polyTrgNode.cpp.

MStatus registerTrgFunction	(	char *	functName,
		polyTrgFnct	funct
	)

Register a triangulation function with maya.

The name provided as a first argument is the name under which the function is registered. This name has to be used when setting 'userTrg' attribute on a mesh.

Parameters

[in]	functName	Function name under which the function is register with maya.
[in]	funct	Pointer to the static function which implement a face triangulation.

Returns: Status code

Status Codes:

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

MStatus unregisterTrgFunction ( char * functName )

Parameters

[in] functName Function name under which the function is register with maya.

Returns: Status code

Status Codes:

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

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

MPxPolyTrg.h
MPxPolyTrg.cpp

MPxPolyTrg Class Reference

Class Description

Public Types

Public Member Functions

Additional Inherited Members

Constructor & Destructor Documentation

Member Function Documentation