class MPxPolyTrg

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Inheritance:

MPxPolyTrg < MPxNode

public members:

	MPxPolyTrg ()
virtual	~MPxPolyTrg ()
virtual void	postConstructor ()
virtual MStatus	compute ( const MPlug & plug, MDataBlock & dataBlock )
virtual bool	isAbstractClass () const
MStatus	registerTrgFunction ( char *name, polyTrgFnct f )
MStatus	unregisterTrgFunction ( char *name )

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

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: setAttr mesh.userTrg -type "string" "triangulate";

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.

Functions

MPxPolyTrg:: MPxPolyTrg ()

Description

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.

MPxPolyTrg:: ~MPxPolyTrg ()

Description

Destructor.

void MPxPolyTrg:: postConstructor ()

Description

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.

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

Description

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.

Arguments

• plug plug representing the attribute that needs to be recomputed
• block data block containing storage for the node's attributes

Return Value

• Status code

Status Codes

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

bool MPxPolyTrg:: isAbstractClass () const

Description Each new node has to implement that fuction. It returns false since this is not an abstract class.

Arguments

Return Value False

MStatus MPxPolyTrg:: registerTrgFunction ( char *functName, polyTrgFnct funct )

Description Register a triangulation function with maya. The name provided as a firrst argument is the name under which the function is registered. This name has to be used when setting 'userTrg' attribute on a mesh.

Arguments

• functName - function name under which the function is register with maya.

• funct - pointer to the static function which implement a face triangulation.

Return Value

• Status code

Status Codes

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

MStatus MPxPolyTrg:: unregisterTrgFunction ( char *functName )

Description

Arguments

• functName - function name under which the function is register with maya.

Return Value

• Status code

Status Codes

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

This class has no child classes.