SoPath(3)

NAME
SoPath - The SoPath class is a container class for traversal path descriptions.

SYNOPSIS

#include <Inventor/SoPath.h>

Inherits SoBase.

Inherited by SoFullPath, and SoNodeKitPath.

  Public Member Functions
SoPath (const int approxlength=4)
SoPath (SoNode *const head)
SoPath (const SoPath &rhs)
SoPath & operator= (const SoPath &rhs)
virtual SoType getTypeId (void) const
Returns the type identification of an object derived from a class inheriting SoBase. This is used for runtime type checking and downward"casting.
void setHead (SoNode *const head)
SoNode * getHead (void) const
void append (const int childindex)
void append (SoNode *const node)
void append (const SoPath *const frompath)
void push (const int childindex)
void pop (void)
SoNode * getTail (void) const
SoNode * getNode (const int index) const
SoNode * getNodeFromTail (const int index) const
int getIndex (const int index) const
int getIndexFromTail (const int index) const
int getLength (void) const
void truncate (const int length)
int findFork (const SoPath *const path) const
int findNode (const SoNode *const node) const
SbBool containsNode (const SoNode *const node) const
SbBool containsPath (const SoPath *const path) const
SoPath * copy (const int startfromnodeindex=0, int numnodes=0) const
void insertIndex (SoNode *const parent, const int newindex)
void removeIndex (SoNode *const parent, const int oldindex)
void replaceIndex (SoNode *const parent, const int index, SoNode *const newchild)
SbBool isRelevantNotification (SoNotList *const l) const
virtual void write (SoWriteAction *action)
Public Member Functions inherited from SoBase
void ref (void) const
void unref (void) const
void unrefNoDelete (void) const
int32_t getRefCount (void) const
void touch (void)
SbBool isOfType (SoType type) const
Returns TRUE if the type of this object is either of the same type or inherited from type.
virtual SbName getName (void) const
virtual void setName (const SbName &newname)
virtual void startNotify (void)
virtual void notify (SoNotList *l)
void addAuditor (void *const auditor, const SoNotRec::Type type)
void removeAuditor (void *const auditor, const SoNotRec::Type type)
const SoAuditorList & getAuditors (void) const
virtual void addWriteReference (SoOutput *out, SbBool isfromfield=FALSE)
SbBool shouldWrite (void)
void assertAlive (void) const

  Static Public Member Functions
static void initClass (void)
Sets up initialization for data common to all instances of this class, like submitting necessary information to the Coin type system.
static SoType getClassTypeId (void)
This static method returns the SoType object associated with objects of this class.
static SoPath * getByName (const SbName name)
static int getByName (const SbName name, SoPathList &l)
Static Public Member Functions inherited from SoBase
static void initClass (void)
Sets up initialization for data common to all instances of this class, like submitting necessary information to the Coin type system.
static SoType getClassTypeId (void)
This static method returns the SoType object associated with objects of this class.
static void addName (SoBase *const base, const char *const name)
static void removeName (SoBase *const base, const char *const name)
static void incrementCurrentWriteCounter (void)
static void decrementCurrentWriteCounter (void)
static SoBase * getNamedBase (const SbName &name, SoType type)
static int getNamedBases (const SbName &name, SoBaseList &baselist, SoType type)
static SbBool read (SoInput *input, SoBase *&base, SoType expectedtype)
static void setInstancePrefix (const SbString &c)
static void setTraceRefs (SbBool trace)
static SbBool getTraceRefs (void)
static SbBool connectRoute (SoInput *input, const SbName &fromnodename, const SbName &fromfieldname, const SbName &tonodename, const SbName &tofieldname)
static SbBool readRoute (SoInput *input)

  Protected Member Functions
virtual ~SoPath ()
void auditPath (const SbBool flag)
Protected Member Functions inherited from SoBase
SoBase (void)
virtual ~SoBase ()
virtual void destroy (void)
SbBool hasMultipleWriteRefs (void) const
SbBool writeHeader (SoOutput *out, SbBool isgroup, SbBool isengine) const
void writeFooter (SoOutput *out) const
virtual const char * getFileFormatName (void) const
virtual SoNotRec createNotRec (void)

  Additional Inherited Members
Protected Types inherited from SoBase
enum BaseFlags { IS_ENGINE = 0x01, IS_GROUP = 0x02 }
Static Protected Member Functions inherited from SoBase
static uint32_t getCurrentWriteCounter (void)
static void staticDataLock (void)
static void staticDataUnlock (void)

Detailed Description

The SoPath class is a container class for traversal path descriptions. SoPath objects contain a list of SoNode pointers and a list of child indices. Indices are necessary to disambiguate situations where a node uses the same node as a child multiple times.

Paths can be export and imported to/from file, like other SoBase derived objects. Read the documentation on the write() method to see how the file format is.

It's important to know the difference between this class and SoFullPath when working with paths. SoPath::getTail() will return the first node in the path that doesn't inherit SoGroup, and getLength() returns the number of nodes down to this node.

If you need the actual path length, or the actual tail node, you need to cast the path to SoFullPath.

Constructor & Destructor Documentation

  SoPath::SoPath (const int approxlength = 4)
The default constructor. approxlength is used to indicate in advance the length of the path to minimize the number of reallocations.

  SoPath::SoPath (SoNode *const head)
A constructor. The argument is set as the head (and only) node of the path.

  SoPath::SoPath (const SoPath & rhs)
Copy constructor. Not part of the original Open Inventor API.

  SoPath::~SoPath (void ) [protected], [virtual]
The destructor is protected as destruction of SoPath instances happens through unref() (as for all objects derived from classes inheriting SoBase).

Member Function Documentation

  SoPath & SoPath::operator= (const SoPath & rhs)
Assignment operator, copies the rhs path into this. Not part of the original Open Inventor API.

  SoType SoPath::getTypeId (void ) const [virtual]

Returns the type identification of an object derived from a class inheriting SoBase. This is used for runtime type checking and "downward" casting. Usage example:

void foo(SoNode * node)
{
  if (node->getTypeId() == SoFile::getClassTypeId()) {
    SoFile * filenode = (SoFile *)node;  // safe downward cast, knows the type
  }
}

For application programmers wanting to extend the library with new nodes, engines, nodekits, draggers or others: this method needs to be overridden in all subclasses. This is typically done as part of setting up the full type system for extension classes, which is usually accomplished by using the predefined macros available through for instance Inventor/nodes/SoSubNode.h (SO_NODE_INIT_CLASS and SO_NODE_CONSTRUCTOR for node classes), Inventor/engines/SoSubEngine.h (for engine classes) and so on.

For more information on writing Coin extensions, see the class documentation of the top level superclasses for the various class groups.

Implements SoBase.

  void SoPath::setHead (SoNode *const node)
This method sets the head of the path to node. If the object already has a path set, it will be truncated.

  SoNode * SoPath::getHead (void ) const
This method returns the head of the path, or NULL if the path is empty.

  void SoPath::append (const int childindex)
This function appends the childindex child of the path's tail to the end of the path. It can only be used after the head is set.

  void SoPath::append (SoNode *const node)
This function adds node to the end if it is a child of the current tail. If path is empty, this is equivalent to calling setHead().

  void SoPath::append (const SoPath *const frompath)
This method appends the path to the end of the path if the head of frompath is either the tail of the path or a child of the path's tail. If the head of frompath is used multiple times as a child of the path tail, the lowest child index is used.

  void SoPath::push (const int childindex) [inline]
This method pushes the child at childindex on the tail on the path.

  void SoPath::pop (void ) [inline]
This method pops the tail off the path.

  SoNode * SoPath::getTail (void ) const
This method returns the tail node of the path. Please note that this method only considers group nodes without hidden children (nodes inheriting SoGroup) when finding the tail.

If you want to find the real tail node (also below node kits and VRML nodes with hidden children), you have to use SoFullPath::getTail(). You don't have to create an SoFullPath instance to do this, just cast the SoPath instance to SoFullPath before getting the tail node:

SoNode * tail = static_cast<SoFullPath*>(path)->getTail();

  SoNode * SoPath::getNode (const int index) const
This method returns the node at index in the path, counted from 0 at the head.

  SoNode * SoPath::getNodeFromTail (const int index) const
This method returns the node at index in the path, counting from the tail. The index argument should be zero or positive.

  int SoPath::getIndex (const int index) const
This method returns the child index of the node at index in the path.

  int SoPath::getIndexFromTail (const int index) const
This method returns the child index of the node at index in the path, counting from the tail. The index argument should be zero or positive.

  int SoPath::getLength (void ) const
This method returns the number of nodes in the path. Only the "visible" nodes are counted, i.e. hidden nodes of e.g. nodekits are not included.

If you need the actual path length, you need to cast your path to SoFullPath and use SoFullPath::getLength().

  void SoPath::truncate (const int length)
This method truncates the path to the given length (i.e. all nodes in the path list from index length and onwards will be removed from the path list).

  int SoPath::findFork (const SoPath *const path) const
This method returns the index of the last node that is the same for both paths, or -1 if the paths don't even start on the same node.

  int SoPath::findNode (const SoNode *const node) const
Returns the index of node if found in the full path (possibly also in the normally hidden parts), or -1 otherwise.

Note that this method is not part of the original Open Inventor API.

  SbBool SoPath::containsNode (const SoNode *const node) const
This method returns TRUE is node is contained somewhere in the full path (possibly also in the normally hidden parts), and FALSE otherwise.

  SbBool SoPath::containsPath (const SoPath *const path) const
This method returns TRUE if path is contained in the path, and FALSE otherwise.

  SoPath * SoPath::copy (const int startfromnodeindex = 0, int numnodes = 0) const
This method returns a copy of the path starting at startfromnodeindex with length numnodes. If numnodes is 0 (default) the path will be copied to the end.

The returned SoPath instance will have an initial reference count of

0.  It is the caller's responsibility to ref() and unref() it according to use.

  SoPath * SoPath::getByName (const SbName name) [static]
This static method is for retrieving an SoPath by its name. The last registered SoPath with the given name is returned, or NULL if no SoPath by name exists.

  int SoPath::getByName (const SbName name, SoPathList & l) [static]
This static method is for finding all the paths with a given name and append them to the l list. The number of SoPath instances with name found is returned.

  void SoPath::insertIndex (SoNode *const parent, const int newindex)
This method is called when a node in the path chain has a child added, to update the index of its child.

newindex is the index of the child which was inserted. If newindex is lower than the index value of the child node stored in the path, the path is updated accordingly.

  void SoPath::removeIndex (SoNode *const parent, const int oldindex)
This method is called when a node in the path chain has a child removed, to update the index of its child.

oldindex was the index of the removed child. If oldindex is lower than or equal to the index value of the child node stored in the path, the path is updated accordingly.

  void SoPath::replaceIndex (SoNode *const parent, const int index, SoNode *const newchild)
This method is called when a node newchild replaces a node in the path. index is the position of the child which has been replaced.

  SbBool SoPath::isRelevantNotification (SoNotList *const l) const
Return TRUE if the notification chain l will affect the path. l will affect the path either if the notification is in the path (the notification started on a field in a node in the path), or off the path (the notification started in a non-separator node that is left of the path's node).

  void SoPath::write (SoWriteAction * action) [virtual]
This method is used to write the contents of an SoPath.

A path is written as:

Path {
  HEAD-NODE-OF-SUBGRAPH
  NUMBER-OF-INDICES
  INDEX0
  INDEX1
  ...
}

[The rest of the documentation for this method only explains the reason behind a mismatch in behavior between the original Open Inventor and Coin. Don't read it if you're not taking a particular interest. (Short version: we do SoPath export in a somewhat more inefficient way to avoid the potential for bugs).]

Note that unlike Open Inventor, we write the complete subgraph below the head node. Only writing the parts of the subgraph affecting the state for nodes within the path is error prone if a subgraph is written out as part of path before it is written out "properly". Consider writing a scene graph which looks like this (in memory):

DEF top_sep Separator {
  Cone { }
  DEF a_sphere Sphere { }
  Cube { }
}
DEF path_switch PathSwitch {
  path Path {
    ...path from "top_sep" to "a_sphere"...
  }
}

..if we now do:

SoSeparator * root = new SoSeparator;
root->addChild([ptr to path_switch]);
root->addChild([ptr to top_sep]);
SoWriteAction wa;
wa.apply(root);

..we would get the scene graph exported like this:

Separator {
  DEF path_switch PathSwitch {
    path Path {
      DEF top_sep Separator {
        DEF a_sphere Sphere {
        }
      }
      1
      0
    }
  }
  USE top_sep
}

..and as you can see, both the Cone and the Cube nodes have vanished, as they were not important for the part per se, and not written as part of it.

This is why we do full subgraph export for head nodes in paths.

  void SoPath::auditPath (const SbBool flag) [protected]
Set whether or not to audit the nodes in the path to detect changes.

Author

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