C++ API Reference

User defined poly triangulation support. More...

#include <MPxPolyTrg.h>

+ 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, kSerialize = kSerial, kGloballySerialize = kGloballySerial
}
 Defines the degree of parallelism of a node. More...
 

Public Member Functions

 MPxPolyTrg ()
 Constructor. More...
 
 ~MPxPolyTrg () override
 Destructor.
 
void postConstructor () override
 Post constructor. More...
 
MStatus compute (const MPlug &plug, MDataBlock &dataBlock) override
 This method should be overridden in user defined nodes. More...
 
bool isAbstractClass () const override
 Each new node has to implement that fuction. More...
 
MStatus registerTrgFunction (const char *name, polyTrgFnct f)
 Register a triangulation function with maya. More...
 
MStatus unregisterTrgFunction (const char *name)
 
- Public Member Functions inherited from MPxNode
 MPxNode ()
 Constructor. More...
 
virtual ~MPxNode ()
 Destructor.
 
virtual bool getInternalValue (const MPlug &, MDataHandle &)
 This method is overridden by nodes that store attribute data in some internal format. More...
 
virtual bool setInternalValue (const MPlug &, const MDataHandle &)
 This method is overridden by nodes that store attribute data in some internal format. More...
 
virtual int internalArrayCount (const MPlug &) 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 &, const MPlug &, 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 &, const MPlug &, 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 void getCacheSetup (const MEvaluationNode &, MNodeCacheDisablingInfo &, MNodeCacheSetupInfo &, MObjectArray &) const
 Provide node-specific setup info for the Cached Playback system. More...
 
virtual void configCache (const MEvaluationNode &, MCacheSchema &) const
 Defines the node's behavior when participating in Cached Playback. More...
 
virtual MTimeRange transformInvalidationRange (const MPlug &source, const MTimeRange &input) const
 Override this method to register this node as an Invalidation-Range-Transformation kernel (IRT kernel) An IRT kernel node will change the invalidation time range for its downstream nodes For example, Dynamics-solver will transform invalidation time range [a,b] to [a,+inf) And Clip-Time-Editor will send out the invalidation range for each of the clip [a,b] to ( [t0+a,t0+b] U [t1+a,t1+b] U [t2+a,t2+b] U ... More...
 
bool hasInvalidationRangeTransformation () const
 Checks if this MPxNode derived node overrides the MPxNode::transformInvalidationRange method.
 
virtual MStatus connectionMade (const MPlug &, const MPlug &, bool asSrc)
 This method gets called when connections are made to attributes of this node. More...
 
virtual MStatus connectionBroken (const MPlug &, const MPlug &, bool asSrc)
 This method gets called when connections are broken with attributes of this node. More...
 
virtual MStatus dependsOn (const MPlug &, const MPlug &, bool &depends) const
 This method may be overridden by the user defined node. More...
 
virtual bool isPassiveOutput (const MPlug &) 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 &, bool &isSaving)
 This method may be overridden by the user defined node. More...
 
virtual MPlug passThroughToOne (const MPlug &) 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 &, MPlugArray &) 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 bool isTrackingTopology () const
 Override this class to return true if this node wants to track topology. 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 &, const MObject &attr) const
 Adds content info to the specified table from a file path attribute. More...
 
bool setExternalContentForFileAttr (const MObject &attr, const MExternalContentLocationTable &)
 Sets content info in the specified attribute from the table. More...
 
virtual void setExternalContent (const MExternalContentLocationTable &)
 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...
 
void _setMPSafe (bool isMPSafe)
 This method is obsolete. More...
 
MDataBlock _forceCache (const MDGContext &)
 This method is obsolete. More...
 
virtual bool getInternalValueInContext (const MPlug &, MDataHandle &, MDGContext &)
 This method is obsolete. More...
 
virtual bool setInternalValueInContext (const MPlug &, const MDataHandle &, MDGContext &)
 This method is obsolete. More...
 
virtual int internalArrayCount (const MPlug &, const MDGContext &) const
 This method is obsolete. 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 MStatus attributeAffects (const MObject &whenChanges, const MObject &isAffected, bool affectsTopology)
 This method is an extension to the other version of the attributeAffects method. 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 ()
 USE _forceCache() 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...
 
virtual void setMPSafe (bool isMPSafe)
 This method is obsolete. More...
 
virtual MDataBlock forceCache (const MDGContext &)
 This method is obsolete. More...
 

Detailed 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:

1 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.

Examples:
polyTrgNode/polyTrgNode.cpp.

Constructor & Destructor Documentation

OPENMAYA_MAJOR_NAMESPACE_OPEN 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 ( )
overridevirtual

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 
)
overridevirtual

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]plugplug representing the attribute that needs to be recomputed
[in]blockdata 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
overridevirtual

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 ( const 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]functNameFunction name under which the function is register with maya.
[in]functPointer 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 ( const char *  functName)
Parameters
[in]functNameFunction 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: