SoDB(3)

NAME
SoDB - The SoDB class keeps track of internal global data.

SYNOPSIS

#include <Inventor/SoDB.h>

  Public Types
typedef SbBool ProgressCallbackType(const SbName &itemid, float fraction, SbBool interruptible, void *userdata)

  Static Public Member Functions
static void init (void)
static void finish (void)
static void cleanup (void)
static const char * getVersion (void)
static SbBool read (SoInput *input, SoPath *&path)
static SbBool read (SoInput *input, SoBase *&base)
static SbBool read (SoInput *input, SoNode *&rootnode)
static SoSeparator * readAll (SoInput *input)
static SoVRMLGroup * readAllVRML (SoInput *input)
static SbBool isValidHeader (const char *teststring)
static SbBool registerHeader (const SbString &headerstring, SbBool isbinary, float ivversion, SoDBHeaderCB *precallback, SoDBHeaderCB *postcallback, void *userdata=NULL)
static SbBool getHeaderData (const SbString &headerstring, SbBool &isbinary, float &ivversion, SoDBHeaderCB *&precallback, SoDBHeaderCB *&postcallback, void *&userdata, SbBool substringok=FALSE)
static int getNumHeaders (void)
static SbString getHeaderString (const int i)
static SoField * createGlobalField (const SbName &name, SoType type)
static SoField * getGlobalField (const SbName &name)
static void renameGlobalField (const SbName &from, const SbName &to)
static void setRealTimeInterval (const SbTime &interval)
static const SbTime & getRealTimeInterval (void)
static void enableRealTimeSensor (SbBool on)
static SoSensorManager * getSensorManager (void)
static void setDelaySensorTimeout (const SbTime &t)
static const SbTime & getDelaySensorTimeout (void)
static int doSelect (int nfds, void *readfds, void *writefds, void *exceptfds, struct timeval *usertimeout)
static void addConverter (SoType from, SoType to, SoType converter)
static SoType getConverter (SoType from, SoType to)
static SbBool isInitialized (void)
static void startNotify (void)
static SbBool isNotifying (void)
static void endNotify (void)
static void addProgressCallback (ProgressCallbackType *func, void *userdata)
static void removeProgressCallback (ProgressCallbackType *func, void *userdata)
static SbBool isMultiThread (void)
static void readlock (void)
static void readunlock (void)
static void writelock (void)
static void writeunlock (void)
static void createRoute (SoNode *from, const char *eventout, SoNode *to, const char *eventin)
static void removeRoute (SoNode *from, const char *eventout, SoNode *to, const char *eventin)

Detailed Description

The SoDB class keeps track of internal global data.

•   !

This class collects various methods for initializing, setting and accessing common global data from the Coin library.

All methods on SoDB are static.

Make sure you call SoDB::init() (either directly or indirectly through the init() method of the GUI glue library) before you use any of the other Coin classes.

Member Typedef Documentation

  SbBool SoDB::ProgressCallbackType
Client code progress callback function must be static functions of this type.

The itemid argument is a unique text identifier which says what is being processed (use this for any GUI progress bar informational text), and fraction is a value in the range [0, 1] which indicates how far the process has got. If the task is successfully aborted, the callback will be invoked a last time with fraction set to -1.0.

The return value is an abort flag indication from the client code. Note that the process that is being run can only be aborted if the interruptible flag is set.

See SoDB::addProgressCallback() for full documentation of how the progress notification mechanism works.

Member Function Documentation

  void SoDB::init (void) [static]
Initialize the Coin system. This needs to be done as the first thing before you start using the library, or you'll probably see an early crash.

  void SoDB::finish (void) [static]
Invoke this method as the last call of the application code, to trigger a cleanup of all static resources used by the Coin library.

This is usually not necessary for standalone executable applications, as the operating system will take care of cleaning up after the process as it exits.

It may be necessary to invoke this method to avoid leaks for 'special' execution environments, though, like if the Coin library is used as e.g. a browser plug-in, or some other type of component which can be started, shut down and restarted multiple times.

Since
    Coin 2.4

    TGS Inventor 5.0

  void SoDB::cleanup (void) [static]
This method was renamed from Coin version 2.4 onwards, to SoDB::finish(). Consider this name for the method obsolete.

Since
    Coin 2.0

  const char * SoDB::getVersion (void) [static]
Returns a text string containing the name of the library and version information.

  SbBool SoDB::read (SoInput * in, SoPath *& path) [static]
Instantiates and reads an SoPath object from in and returns a pointer to it in path.

The reference count of the SoPath object will initially be zero.

Returns FALSE on error. Returns TRUE with path equal to NULL if we hit end of file instead of a new path specification in the file.

  SbBool SoDB::read (SoInput * in, SoBase *& base) [static]
Instantiates and reads an object of type SoBase from in and returns a pointer to it in base. base will be NULL on return if we hit end of file.

The reference count of the base object will initially be zero.

Returns FALSE on error.

  SbBool SoDB::read (SoInput * in, SoNode *& rootnode) [static]
Instantiates and reads an object of type SoNode from in and returns a pointer to it in rootnode.

The reference count of the node will initially be zero.

Returns FALSE on error. Returns TRUE with rootnode equal to NULL if we hit end of file instead of a new node specification in the file.

  SoSeparator * SoDB::readAll (SoInput * in) [static]
Reads all graphs from in and returns them under an SoSeparator node. If the file contains only a single graph under an SoSeparator node (which is the most common way of constructing and exporting scene graphs), no extra SoSeparator root node will be made, but the returned root node will be the top-most node from the file.

The reference count of the root separator returned from this method will be zero. Other nodes in the returned scene graph will have reference counts according to the number of parent-child relationships, as usual.

The common layout for how to load, work with and then finally destruct and return memory resources of scene graphs usually goes like this:

// [snip]
SoInput in;
if (!in.openFile(filename)) { exit(1); }
SoSeparator * root = SoDB::readAll(&in);
if (!root) { exit(1); }
// root-node returned from SoDB::readAll() has initial zero
// ref-count, so reference it before we start using it to
// avoid premature destruction.
root->ref();
// [do your thing here -- attach the scene to a viewer or whatever]
// Bring ref-count of root-node back to zero to cause the
// destruction of the scene.
root->unref();
// (Upon self-destructing, the root-node will also dereference
// its children nodes, so they also self-destruct, and so on
// recursively down the scene graph hierarchy until the complete
// scene graph has self-destructed and thereby returned all
// memory resources it was using.)

Returns NULL on any error.

Tip: a common operation to do after importing a scene graph is to pick out the memory pointers to one or more of the imported nodes for further handling. This can be accomplished by using either the SoNode::getByName() function (which is the easier approach) or by using an instance of the SoSearchAction class (which is the more complex but also more flexible approach).

  SoVRMLGroup * SoDB::readAllVRML (SoInput * in) [static]
Same as SoDB::readAll(), except it return an SoVRMLGroup instead of an SoSeparator.

See also
    SoDB::readAll()

Since
    Coin 2.0

  SbBool SoDB::isValidHeader (const char * teststring) [static]
Check if testString is a valid file format header identifier string.

See also
    getHeaderData(), registerHeader()

  SbBool SoDB::registerHeader (const SbString & headerstring, SbBool isbinary, float ivversion, SoDBHeaderCB * precallback, SoDBHeaderCB * postcallback, void * userdata = NULL) [static]
Register a header string which should be recognized by SoInput upon file import. This is a convenient way for library users to register their own VRML or Coin derived file formats.

Set isbinary to TRUE if the file should be read as binary data, and set ivversion to indicate which Coin library version is needed to read the file.

Callbacks precallback and postcallback will be called before and after importing the custom format.

If headerstring cannot be accepted as a valid file format header for Coin files, FALSE will be returned. A valid header must start with a '#' character, and not be more than 80 characters long.

See also
    getHeaderData()

  SbBool SoDB::getHeaderData (const SbString & headerstring, SbBool & isbinary, float & ivversion, SoDBHeaderCB *& precallback, SoDBHeaderCB *& postcallback, void *& userdata, SbBool substringok = FALSE) [static]
Returns the settings for the given headerstring, if headerstring is a valid header.

If substringok is TRUE, ignore trailing characters in headerstring when checking for validity.

If no valid header string by this name is found, FALSE is returned, otherwise TRUE will be returned, and the other input arguments will be set to their respective values.

See also
    isValidHeader(), registerHeader()

  int SoDB::getNumHeaders (void) [static]
Returns number of registered file headers.

See also
    getHeaderString()

  SbString SoDB::getHeaderString (const int i) [static]
Returns the identifier header string of index i.

See also
    getNumHeaders(), getHeaderData()

  SoField * SoDB::createGlobalField (const SbName & name, SoType type) [static]
Create a new global field by the given type, and identified in subsequent accesses to getGlobalField() by name. If a global field by the name and type already exists, returns a pointer to it. If a global field with the same name but a different type exists, returns NULL.

A global field can be deallocated by calling SoDB::renameGlobalField(), with the second argument set to an empty string.

See also
    getGlobalField(), renameGlobalField()

  SoField * SoDB::getGlobalField (const SbName & name) [static]
If there exist a global field with the given name, return a pointer to it. If there is no field with this name, return NULL.

Of particular interest is the realTime global field set up by the library on initialization. This field is used as a source field to all the autonomous animation objects within the library, like for instance the SoTimeCounter engine or the SoRotor node.

If you want to control the speed of 'action' of a scene with animating / moving components (for instance for doing fixed frame-time snapshots for generating a movie), grab the global field named 'realTime' and use it in the manner depicted in the class documentation of the SoOffscreenRenderer class.

See also
    createGlobalField(), renameGlobalField()

  void SoDB::renameGlobalField (const SbName & from, const SbName & to) [static]
Rename a global field. If to is an empty name, the from field gets deleted. If another global field already goes by the name to, that field will get deleted before the rename operation.

See also
    getGlobalField(), createGlobalField()

  void SoDB::setRealTimeInterval (const SbTime & interval) [static]
Set the time interval between updates for the realTime global field to interval. Default value is 1/12 s.

The low update rate is due to historical reasons, to be compatible with application code written for SGI Inventor.

Setting the interval to a zero time will disable automatic updates of the realTime field.

See also
    getRealTimeInterval(), getGlobalField()

  const SbTime & SoDB::getRealTimeInterval (void) [static]
Returns the current trigger interval for the global realTime SbTime field.

See also
    setRealTimeInterval(), getGlobalField()

  void SoDB::enableRealTimeSensor (SbBool on) [static]
Turn on or off the real time sensor.

The most common use for turning the real time sensor off is to control the realTime global field from the user application. This is for instance handy when you want to take screen snapshots at fixed intervals. See the class documentation of SoOffscreenRenderer for further information.

See also
    setRealTimeInterval(), getGlobalField()

  SoSensorManager * SoDB::getSensorManager (void) [static]
Returns a pointer to the global sensor manager. The sensor manager keeps track of the sensor queues.

  void SoDB::setDelaySensorTimeout (const SbTime & t) [static]
This is just a wrapper for the method in SoSensorManager by the same name.

See also
    getDelaySensorTimeout(), SoSensorManager

  const SbTime & SoDB::getDelaySensorTimeout (void) [static]
This is just a wrapper for the method in SoSensorManager by the same name.

See also
    setDelaySensorTimeout(), SoSensorManager

  int SoDB::doSelect (int nfds, void * readfds, void * writefds, void * exceptfds, struct timeval * usertimeout) [static]
NOTE: THIS METHOD IS OBSOLETED. DON'T USE IT.

This is a wrapper around the POSIX select() call. It is provided so you can do synchronous I/O while Coin continues to handle sensor events, rendering, etc. The parameters are the same as for select(), so check your system documentation on how to use them.

The void* arguments must be valid pointers to fd_set structures. We've changed this from the original SGI Inventor API to avoid messing up the header file with system-specific includes.

NOTE: THIS METHOD IS OBSOLETED. DON'T USE IT.

  void SoDB::addConverter (SoType from, SoType to, SoType converter) [static]
Notify SoDB that there exists a way to convert data from the from SoField type to the to SoField type, by connecting them with an instance of the converter SoFieldConverter type.

By doing this, SoDB::getConverter() will later be able to automatically return the type of the correct conversion class when requested.

Coin internally provides conversion between most field types, so application programmers should usually not need to use this function. The exception is if you are writing your own field type classes, and want to be able to connect them to the internal field types (or other extensions field types).

See also
    createConverter(), SoFieldConverter

  SoType SoDB::getConverter (SoType from, SoType to) [static]
Return the type of an SoFieldConverter class which is able to convert data between fields of type from to the data field(s) of field type to.

If no conversion between the given field types is possible, returns SoType::badType().

See also
    addConverter()

  SbBool SoDB::isInitialized (void) [static]
Returns TRUE if init() has been called.

See also
    init()

  void SoDB::startNotify (void) [static]
This API member is considered internal to the library, as it is not likely to be of interest to the application programmer.

  SbBool SoDB::isNotifying (void) [static]
This API member is considered internal to the library, as it is not likely to be of interest to the application programmer.

  void SoDB::endNotify (void) [static]
This API member is considered internal to the library, as it is not likely to be of interest to the application programmer.

  void SoDB::addProgressCallback (ProgressCallbackType * func, void * userdata) [static]
The concept behind progress information in Coin is that any internal process which may take a long time to complete (like e.g. file import for huge scenes) can pass on progress information by calling back to a progress callback set up by the code of the client application.

The client's progress callback's function signature must match the SoDB::ProgressCallbackType.

The mechanism works by enforcing that all progress notification from within Coin must

1.  Use a unique text id to identify the 'progress-informing' process (e.g. 'File import' for SoDB::readAll() / SoInput file reading, 'File export' for SoOutput / SoWriteAction, etc). This is the itemid name passed on to the progress callback.
2.  The first invocation of the user callback will be done with an exact 0.0 fraction value.
3.  The last invocation will be done with an exact 1.0 fraction value.
4.  An exception to the last point is that if the process is aborted, a final invocation with a -1.0 fraction value will be made.
One important thing to note about the mechanism is that processes with progress callbacks can be running within other processes using the progress callback functionality. Progress information will then have to be considered to be 'stacked', and client code must be aware of and treat this properly.
This function is an extension for Coin, and it is not available in the original SGI Open Inventor v2.1 API.

Since
    Coin 2.2

  void SoDB::removeProgressCallback (ProgressCallbackType * func, void * userdata) [static]
Removes a progress callback function, which will no longer be invoked.

  SbBool SoDB::isMultiThread (void) [static]
Returns TRUE if this is a thread safe version of Coin (i.e. it was configured and built with --enable-threadsafe).

  void SoDB::readlock (void) [static]
Places a read lock on the global SoDB mutex. This can be used to synchronize between threads that are reading/writing Coin scene graphs.
If you call this function, you must make sure that you also call SoDB::readunlock(). If you fail to do this, you might experience that your application locks up.
All Coin actions have a read-lock on the global SoDB mutex while traversing the scene graph.
See also
    SoDB::readunlock(), SoDB::writelock()
Since
    Coin 2.3
    TGS Inventor 3.0

  void SoDB::readunlock (void) [static]
Unlocks the read lock on the global SoDB mutex.
See also
    SoDB::readlock()
Since
    Coin 2.3
    TGS Inventor 3.0

  void SoDB::writelock (void) [static]
Places a write lock on the global SoDB mutex. This can be used to prevent that the scene graph is read or traversed while you modify the scene graph.
If you call this function, you must make sure that you also call SoDB::writeunlock(). If you fail to do this, you might experience that your application locks up.
See also
    SoDB::readlock()
Since
    Coin 2.3
    TGS Inventor 3.0

  void SoDB::writeunlock (void) [static]
Unlocks the write lock on the global SoDB mutex.
See also
    SoDB::writelock()
Since
    Coin 2.3
    TGS Inventor 3.0

  void SoDB::createRoute (SoNode * fromnode, const char * eventout, SoNode * tonode, const char * eventin) [static]
Create a connection from one VRML97 node field to another.
('Routes' are what field-to-field connections are called for the VRML97 standard.)
Connections made in this manner will be persistent upon file export.
See also
    SoDB::removeRoute()
    SoField::connectFrom(SoField*)
Since
    Coin 2.4
    TGS Inventor 2.6

  void SoDB::removeRoute (SoNode * fromnode, const char * eventout, SoNode * tonode, const char * eventin) [static]
Removes a field-to-field connection.
See also
    SoDB::createRoute()
    SoField::disconnect(SoField*)
Since
    Coin 2.4
    TGS Inventor 2.6

Author
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