SoVRMLBillboard.3coin4 - Man Page

The SoVRMLBillboard class is used for rotating geometry towards the viewpoint.

Synopsis

#include <Inventor/VRMLnodes/SoVRMLBillboard.h>

Inherits SoVRMLParent.

virtual SoType getTypeId (void) const
SoVRMLBillboard (void)
SoVRMLBillboard (int numchildren)
virtual void doAction (SoAction *action)
virtual void callback (SoCallbackAction *action)
virtual void GLRender (SoGLRenderAction *action)
virtual void getBoundingBox (SoGetBoundingBoxAction *action)
virtual void getMatrix (SoGetMatrixAction *action)
virtual void pick (SoPickAction *action)
virtual void search (SoSearchAction *action)
virtual void GLRenderBelowPath (SoGLRenderAction *action)
virtual void GLRenderInPath (SoGLRenderAction *action)
virtual void GLRenderOffPath (SoGLRenderAction *action)
virtual void notify (SoNotList *list)

Public Member Functions inherited from SoVRMLParent
virtual SbBool affectsState (void) const
virtual void addChild (SoNode *child)
virtual void insertChild (SoNode *child, int idx)
virtual SoNode * getChild (int idx) const
virtual int findChild (const SoNode *child) const
virtual int getNumChildren (void) const
virtual void removeChild (int idx)
virtual void removeChild (SoNode *child)
virtual void removeAllChildren (void)
virtual void replaceChild (int idx, SoNode *child)
virtual void replaceChild (SoNode *old, SoNode *child)
virtual SoChildList * getChildren (void) const
virtual void write (SoWriteAction *action)
virtual void getPrimitiveCount (SoGetPrimitiveCountAction *action)

Public Member Functions inherited from SoGroup
SoGroup (void)
SoGroup (int nchildren)
virtual void handleEvent (SoHandleEventAction *action)
virtual void audioRender (SoAudioRenderAction *action)
virtual void addWriteReference (SoOutput *out, SbBool isfromfield=FALSE)

Public Member Functions inherited from SoNode
void setOverride (const SbBool state)
SbBool isOverride (void) const
void setNodeType (const NodeType type)
NodeType getNodeType (void) const
virtual SoNode * copy (SbBool copyconnections=FALSE) const
virtual void rayPick (SoRayPickAction *action)
virtual void grabEventsSetup (void)
virtual void grabEventsCleanup (void)
virtual void startNotify (void)
SbUniqueId getNodeId (void) const
virtual void writeInstance (SoOutput *out)
virtual SoNode * addToCopyDict (void) const
virtual SoFieldContainer * copyThroughConnection (void) const

Public Member Functions inherited from SoFieldContainer
void setToDefaults (void)
SbBool hasDefaultValues (void) const
SbBool fieldsAreEqual (const SoFieldContainer *container) const
void copyFieldValues (const SoFieldContainer *container, SbBool copyconnections=FALSE)
SbBool set (const char *const fielddata)
void get (SbString &fielddata)
virtual int getFields (SoFieldList &l) const
virtual int getAllFields (SoFieldList &l) const
virtual SoField * getField (const SbName &name) const
virtual SoField * getEventIn (const SbName &name) const
virtual SoField * getEventOut (const SbName &name) const
SbBool getFieldName (const SoField *const field, SbName &name) const
SbBool enableNotify (const SbBool flag)
SbBool isNotifyEnabled (void) const
SbBool set (const char *fielddata, SoInput *input)
void get (SbString &fielddata, SoOutput *out)
virtual SbBool validateNewFieldValue (SoField *field, void *newval)
SbBool getIsBuiltIn (void) const
virtual void getFieldsMemorySize (size_t &managed, size_t &unmanaged) const
void setUserData (void *userdata) const
void * getUserData (void) const

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)
void addAuditor (void *const auditor, const SoNotRec::Type type)
void removeAuditor (void *const auditor, const SoNotRec::Type type)
const SoAuditorList & getAuditors (void) const
SbBool shouldWrite (void)
void assertAlive (void) const

Static Public Member Functions

static SoType getClassTypeId (void)
static void initClass (void)

Static Public Member Functions inherited from SoVRMLParent
static SoType getClassTypeId (void)
static void initClass (void)
static void updateChildList (const SoNode *const *nodes, const int numnodes, SoChildList &cl)
static void updateChildList (SoNode *nodewithsfnode, SoChildList &cl)

Static Public Member Functions inherited from SoGroup
static SoType getClassTypeId (void)
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 Public Member Functions inherited from SoNode
static uint32_t getCompatibilityTypes (const SoType &nodetype)
static SoType getClassTypeId (void)
static SoNode * getByName (const SbName &name)
static int getByName (const SbName &name, SoNodeList &l)
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 void initClasses (void)
static SbUniqueId getNextNodeId (void)
static int getActionMethodIndex (const SoType type)
static void getBoundingBoxS (SoAction *action, SoNode *node)
static void GLRenderS (SoAction *action, SoNode *node)
static void callbackS (SoAction *action, SoNode *node)
static void getMatrixS (SoAction *action, SoNode *node)
static void handleEventS (SoAction *action, SoNode *node)
static void pickS (SoAction *action, SoNode *node)
static void rayPickS (SoAction *action, SoNode *node)
static void searchS (SoAction *action, SoNode *node)
static void writeS (SoAction *action, SoNode *node)
static void audioRenderS (SoAction *action, SoNode *node)
static void getPrimitiveCountS (SoAction *action, SoNode *node)

Static Public Member Functions inherited from SoFieldContainer
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 cleanupClass (void)
static void initCopyDict (void)
static void addCopy (const SoFieldContainer *orig, const SoFieldContainer *copy)
static SoFieldContainer * checkCopy (const SoFieldContainer *orig)
static SoFieldContainer * findCopy (const SoFieldContainer *orig, const SbBool copyconnections)
static void copyDone (void)

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)

Public Attributes

SoSFVec3f axisOfRotation
SoSFVec3f bboxCenter
SoSFVec3f bboxSize

Public Attributes inherited from SoVRMLParent
SoMFNode children

Protected Member Functions

virtual const SoFieldData * getFieldData (void) const
virtual ~SoVRMLBillboard ()

Protected Member Functions inherited from SoVRMLParent
SoVRMLParent (void)
SoVRMLParent (int approxchildren)
virtual ~SoVRMLParent ()
virtual SbBool readInstance (SoInput *in, unsigned short flags)
virtual void copyContents (const SoFieldContainer *from, SbBool copyConn)

Protected Member Functions inherited from SoGroup
virtual ~SoGroup ()
virtual SbBool readChildren (SoInput *in)
virtual SoNotRec createNotRec (void)
void setOperation (const SoNotRec::OperationType opType=SoNotRec::UNSPECIFIED, const SoNode *cc=NULL, const SoNode *pc=NULL, const int ci=-1)

Protected Member Functions inherited from SoNode
SoNode (void)
virtual ~SoNode ()

Protected Member Functions inherited from SoFieldContainer
SoFieldContainer (void)
virtual ~SoFieldContainer ()

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

Static Protected Member Functions

static const SoFieldData ** getFieldDataPtr (void)

Static Protected Member Functions inherited from SoVRMLParent
static const SoFieldData ** getFieldDataPtr (void)

Static Protected Member Functions inherited from SoGroup
static const SoFieldData ** getFieldDataPtr (void)

Static Protected Member Functions inherited from SoNode
static const SoFieldData ** getFieldDataPtr (void)
static void setNextActionMethodIndex (int index)
static int getNextActionMethodIndex (void)
static void incNextActionMethodIndex (void)
static void setCompatibilityTypes (const SoType &nodetype, const uint32_t bitmask)

Static Protected Member Functions inherited from SoBase
static uint32_t getCurrentWriteCounter (void)
static void staticDataLock (void)
static void staticDataUnlock (void)

Additional Inherited Members

Public Types inherited from SoNode

enum NodeType { INVENTOR = 0x0000, VRML1 = 0x0001, VRML2 = 0x0002, INVENTOR_1 = 0x0004, INVENTOR_2_0 = 0x0008, INVENTOR_2_1 = 0x0010, INVENTOR_2_5 = 0x0020, INVENTOR_2_6 = 0x0040, COIN_1_0 = 0x0080, COIN_2_0 = 0x0100, EXTENSION = 0x0200, COIN_2_2 = 0x0400, COIN_2_3 = 0x0800, COIN_2_4 = 0x1000, INVENTOR_5_0 = 0x2000, COIN_2_5 = 0x4000, COIN_3_0 = 0x8000, INVENTOR_6_0 = 0x10000, COIN_4_0 = 0x20000 }

Protected Types inherited from SoBase
enum BaseFlags { IS_ENGINE = 0x01, IS_GROUP = 0x02 }

Protected Attributes inherited from SoVRMLParent
SoMFNode addChildren
SoMFNode removeChildren

Protected Attributes inherited from SoGroup
SoChildList * children

Protected Attributes inherited from SoNode
SbUniqueId uniqueId

Protected Attributes inherited from SoFieldContainer
SbBool isBuiltIn

Static Protected Attributes inherited from SoNode
static SbUniqueId nextUniqueId = 1
static int nextActionMethodIndex = 0

Detailed Description

The SoVRMLBillboard class is used for rotating geometry towards the viewpoint.

The detailed class documentation is taken verbatim from the VRML97 standard (ISO/IEC 14772-1:1997). It is copyright The Web3D Consortium, and is used by permission of the Consortium:

Billboard {
  eventIn      MFNode   addChildren
  eventIn      MFNode   removeChildren
  exposedField SFVec3f  axisOfRotation 0 1 0     # (-inf, inf)
  exposedField MFNode   children       []
  field        SFVec3f  bboxCenter     0 0 0     # (-inf, inf)
  field        SFVec3f  bboxSize       -1 -1 -1  # (0, inf) or -1,-1,-1
}

The Billboard node is a grouping node which modifies its coordinate system so that the Billboard node's local Z-axis turns to point at the viewer. The Billboard node has children which may be other children nodes. The axisOfRotation field specifies which axis to use to perform the rotation. This axis is defined in the local coordinate system. When the axisOfRotation field is not (0, 0, 0), the following steps describe how to rotate the billboard to face the viewer:

a. Compute the vector from the Billboard node's origin to the viewer's position. This vector is called the billboard-to-viewer vector.
b. Compute the plane defined by the axisOfRotation and the billboard-to-viewer vector.
c. Rotate the local Z-axis of the billboard into the plane from b., pivoting around the axisOfRotation.

When the axisOfRotation field is set to (0, 0, 0), the special case of viewer-alignment is indicated. In this case, the object rotates to keep the billboard's local Y-axis parallel with the Y-axis of the viewer. This special case is distinguished by setting the axisOfRotation to (0, 0, 0). The following steps describe how to align the billboard's Y-axis to the Y-axis of the viewer:

d. Compute the billboard-to-viewer vector.
e. Rotate the Z-axis of the billboard to be collinear with the billboard-to-viewer vector and pointing towards the viewer's position.
f. Rotate the Y-axis of the billboard to be parallel and oriented in the same direction as the Y-axis of the viewer.

If the axisOfRotation and the billboard-to-viewer line are coincident, the plane cannot be established and the resulting rotation of the billboard is undefined. For example, if the axisOfRotation is set to (0,1,0) (Y-axis) and the viewer flies over the billboard and peers directly down the Y-axis, the results are undefined. Multiple instances of Billboard nodes (DEF/USE) operate as expected: each instance rotates in its unique coordinate system to face the viewer. Subclause 4.6.5, Grouping and children nodes (http://www.web3d.org/documents/specifications/14772/V2.0/part1/concepts.html#4.6.5), provides a description of the children, addChildren, and removeChildren fields and eventIns. The bboxCenter and bboxSize fields specify a bounding box that encloses the Billboard node's children. This is a hint that may be used for optimization purposes. The results are undefined if the specified bounding box is smaller than the actual bounding box of the children at any time. A default bboxSize value, (-1, -1, -1), implies that the bounding box is not specified and if needed shall be calculated by the browser. A description of the bboxCenter and bboxSize fields is contained in 4.6.4, Bounding boxes (http://www.web3d.org/documents/specifications/14772/V2.0/part1/concepts.html#4.6.4),

The rest of this class documentation is not from the VRML97 standards documentation, but was written specifically for the Coin3D API documentation.

The following example VRML scene is a simple illustration of how SoVRMLBillboard::axisOfRotation constrains rotation around the given vector:

#VRML V2.0 utf8

Transform {
   translation -2 0 0
   children [
      Billboard {
        children [ Box { } ]
      }
   ]
}

Transform {
   translation 2 0 0
   children [
      Billboard {
        axisOfRotation 0 1 0
        children [ Box { } ]
      }
   ]
}

Transform {
   translation 0 -2 0
   children [ Box { size 10 0.1 10 } ]
}

Constructor & Destructor Documentation

SoVRMLBillboard::SoVRMLBillboard (void)

Constructor.

SoVRMLBillboard::SoVRMLBillboard (int numchildren)

Constructor. numchildren is the expected number of children.

SoVRMLBillboard::~SoVRMLBillboard () [protected], [virtual]

Destructor.

Member Function Documentation

SoType SoVRMLBillboard::getClassTypeId (void) [static]

This static method returns the SoType object associated with objects of this class.

SoType SoVRMLBillboard::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.

Reimplemented from SoVRMLParent.

const SoFieldData ** SoVRMLBillboard::getFieldDataPtr (void) [static], [protected]

This API member is considered internal to the library, as it is not likely to be of interest to the application programmer.

Returns the SoFieldData class which holds information about fields in this node.

const SoFieldData * SoVRMLBillboard::getFieldData (void) const [protected], [virtual]

Returns a pointer to the class-wide field data storage object for this instance. If no fields are present, returns NULL.

Reimplemented from SoVRMLParent.

void SoVRMLBillboard::initClass (void) [static]

void SoVRMLBillboard::doAction (SoAction * action) [virtual]

This function performs the typical operation of a node for any action.

Reimplemented from SoVRMLParent.

void SoVRMLBillboard::callback (SoCallbackAction * action) [virtual]

Action method for SoCallbackAction.

Simply updates the state according to how the node behaves for the render action, so the application programmer can use the SoCallbackAction for extracting information about the scene graph.