SoBillboard Class Reference

Grouping node that modifies its coordinate system so that its local Z-axis always points at the viewer. More...

#include <Inventor/nodes/SoBillboard.h>

Inheritance diagram for SoBillboard:

Public Member Functions
virtual SoType	getTypeId () const
	Returns the type identifier for this specific instance.
	SoBillboard ()
	Constructor.
	SoBillboard (int nChildren)
	Constructor that takes approximate number of children.
Public Member Functions inherited from SoSeparator
	SoSeparator ()
	Creates a separator node with default settings.
	SoSeparator (int nChildren)
	Constructor that takes approximate number of children.
Public Member Functions inherited from SoGroup
	SoGroup ()
	Creates an empty group node.
	SoGroup (int nChildren)
	Constructor that takes approximate number of children.
virtual void	addChild (SoNode *child)
	Adds a child as last one in group.
virtual void	insertChild (SoNode *child, int newChildIndex)
	Adds a child so that it becomes the one with the given index.
virtual SoNode *	getChild (int index) const
	Returns pointer the child node with the given index.
virtual int	findChild (const SoNode *child) const
	Finds index of given child within group.
virtual int	getNumChildren () const
	Returns number of children.
virtual void	removeChild (int index)
	Removes child with given index from group.
virtual void	removeChild (SoNode *child)
	Removes first instance of given child from group.
virtual void	removeAllChildren ()
	Removes all children from group.
virtual void	replaceChild (int index, SoNode *newChild)
	Replaces child with given index with new child.
virtual void	replaceChild (SoNode *oldChild, SoNode *newChild)
	Replaces first instance of given child with new child.
Public Member Functions inherited from SoNode
virtual void	setOverride (const SbBool state)
	Turns the override flag on or off.
virtual SbBool	isOverride () const
	Returns the state of the override flag.
virtual SoNode *	copy (SbBool copyConnections=FALSE) const
	Creates and returns an exact copy of the node.
virtual void	touch ()
	Marks an instance as modified, simulating a change to it.
Public Member Functions inherited from SoFieldContainer
void	setToDefaults ()
	Sets all fields in this object to their default values.
SbBool	hasDefaultValues () const
	Returns TRUE if all of the object's fields have their default values.
SbBool	fieldsAreEqual (const SoFieldContainer *fc) const
	Returns TRUE if this object's fields are exactly equal to fc's fields.
void	copyFieldValues (const SoFieldContainer *fc, SbBool copyConnections=FALSE)
	Copies the contents of fc's fields into this object's fields.
SoNONUNICODE SbBool	set (const char *fieldDataString)
	Sets one or more fields in this object to the values specified in the given string, which should be a string in the Open Inventor file format.
SbBool	set (const SbString &fieldDataString)
	Sets one or more fields in this object to the values specified in the given string, which should be a string in the Open Inventor file format.
void	get (SbString &fieldDataString)
	Returns the values of the fields of this object in the Open Inventor ASCII file format in the given string.
virtual int	getFields (SoFieldList &list) const
	Appends references to all of this object's fields to resultList, and returns the number of fields appended.
virtual int	getAllFields (SoFieldList &list) const
	Returns a list of fields, including the eventIn's and eventOut's.
virtual SoField *	getField (const SbName &fieldName) const
	Returns a the field of this object whose name is fieldName.
virtual SoField *	getEventIn (const SbName &fieldName) const
	Returns a the eventIn with the given name.
virtual SoField *	getEventOut (const SbName &fieldName) const
	Returns the eventOut with the given name.
SbBool	getFieldName (const SoField *field, SbName &fieldName) const
	Returns the name of the given field in the fieldName argument.
SbBool	enableNotify (SbBool flag)
	Notification at this Field Container is enabled (if flag == TRUE) or disabled (if flag == FALSE).
SbBool	isNotifyEnabled () const
	Notification is the process of telling interested objects that this object has changed.
virtual void	setUserData (void *data)
	Sets application data.
void *	getUserData (void) const
	Gets user application data.
Public Member Functions inherited from SoBase
virtual SbName	getName () const
	Returns the name of an instance.
virtual void	setName (const SbName &name)
	Sets the name of an instance.
void	setSynchronizable (const bool b)
	Sets this to be a ScaleViz synchronizable object.
bool	isSynchronizable () const
	Gets the ScaleViz synchronizable state of this object.
Public Member Functions inherited from SoRefCounter
void	ref () const
	Adds a reference to an instance.
void	unref () const
	Removes a reference from an instance.
void	unrefNoDelete () const
	unrefNoDelete() should be called when it is desired to decrement the reference count, but not delete the instance if this brings the reference count to zero.
int	getRefCount () const
	Returns current reference count.
void	lock () const
	lock this instance.
void	unlock () const
	unlock this instance.
Public Member Functions inherited from SoTypedObject
SbBool	isOfType (const SoType &type) const
	Returns TRUE if this object is of the type specified in type or is derived from that type.
template<typename TypedObjectClass >
SbBool	isOfType () const
	Returns TRUE if this object is of the type of class TypedObjectClass or is derived from that class.

Static Public Member Functions
static SoType	getClassTypeId ()
	Returns the type identifier for this class.
Static Public Member Functions inherited from SoSeparator
static SoType	getClassTypeId ()
	Returns the type identifier for this class.
Static Public Member Functions inherited from SoGroup
static SoType	getClassTypeId ()
	Returns the type identifier for this class.
Static Public Member Functions inherited from SoNode
static SoType	getClassTypeId ()
	Returns the type identifier for this class.
static SoNode *	getByName (const SbName &name)
	A node's name can be set using SoBase::setName().
static int	getByName (const SbName &name, SoNodeList &list)
	A node's name can be set using SoBase::setName().
Static Public Member Functions inherited from SoFieldContainer
static SoType	getClassTypeId ()
	Returns the type of this class.
Static Public Member Functions inherited from SoBase
static SoType	getClassTypeId ()
	Returns type identifier for this class.
Static Public Member Functions inherited from SoTypedObject
static SoType	getClassTypeId ()
	Returns the type identifier for this class.

Public Attributes
SoSFVec3f	axisOfRotation
	Specifies which axis to use to perform the rotation.
SoSFBool	useSphereBBox
	Specifies if the bounding box returned by SoBillboard::getBoundingBox() method should be extended to completely contain the bounding sphere of the children.
Public Attributes inherited from SoSeparator
SoSFEnum	boundingBoxCaching
	Whether to cache during bounding box traversal.
SoSFEnum	renderCulling
	Whether to cull during rendering traversal.
SoSFEnum	pickCulling
	Whether to cull during picking traversal.
SoSFEnum	fastEditing
	Specifies the fast edit mode of the separator node.
SoSFInt32	renderUnitId
	Used during the ScaleViz depth compositing process, this field specifies which render unit (OIRU) will render the sub scene graph below this separator.
SoDEPRECATED SoSFEnum	renderCaching
	Whether to cache during rendering traversal.
Public Attributes inherited from SoGroup
SoSFBool	boundingBoxIgnoring
	Whether to ignore this node during bounding box traversal.

Additional Inherited Members
Public Types inherited from SoSeparator
enum	CacheEnabled {   OFF ,   ON ,   AUTO }
	Possible values for caching. More...
enum	FastEditing {   DISABLE = 0x01 ,   KEEP_ZBUFFER = 0x02 ,   CLEAR_ZBUFFER = 0x03 }
	Fast editing policy enumeration values. More...
Related Symbols inherited from SoSeparator
#define	SO_RENDERUNITID_NONE   (-1)
	Don't traverse any children.
#define	SO_RENDERUNITID_INHERIT   (-2)
	Inherit value from state.
#define	SO_RENDERUNITID_ALL   (-3)
	Traverse all children.

Detailed Description

Grouping node that modifies its coordinate system so that its local Z-axis always points at the viewer.

The SoBillboard 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 children of an SoBillboard node may include other grouping nodes as well as shape nodes.

Performance:

• SoBillboard nodes recompute the screen alignment transformation on every render traversal. A large number of billboard nodes will reduce performance.
• The orientation of an SoBillboard depends on the current camera settings, so this node should not be render cached.
• SoBillboard nodes prohibit auto-caching, so no SoSeparator (or other render caching node) above an SoBillboard in the scene graph will automatically create a render cache. This can significantly reduce performance and applications should put nodes that can be render cached (especially geometry nodes) under their own SoSeparator below the SoBillboard.
• We recommend leaving the useSphereBBox field set to true.
  This will significantly improve performance when using billboard nodes.

Export limitations:

• SoBillboard can be exported to PDF3D/U3D (SoToPDFAction) as a group node, but due to limitations of that file format, it will not act as a billboard. In other words, the geometry will not be "screen locked".

The axisOfRotation field specifies which axis to use to perform the rotation. This axis is defined in the local coordinates of the SoBillboard node. The default (0,1,0) is useful for objects such as images of trees and lamps positioned on a ground plane. But when an object is oriented at an angle, for example, on the incline of a mountain, then the axisOfRotation may also need to be oriented at a similar angle.

A special case of billboarding is screen-alignment – the object rotates to always stay aligned with the viewer even when the viewer elevates, pitches and rolls. This special case is distinguished by setting the axisOfRotation to (0, 0, 0).

To rotate the SoBillboard to face the viewer, determine the line between the SoBillboard's origin and the viewer's position; call this the billboard-to-viewer line. The axisOfRotation and the billboard-to-viewer line define a plane. The local z-axis of the SoBillboard is then rotated into that plane, pivoting around the axisOfRotation.

If the axisOfRotation and the billboard-to-viewer line are coincident (the same line), then the plane cannot be established, and the rotation results of the SoBillboard are undefined. For example, if the axisOfRotation is set to (0,1,0) (Y-axis) and the viewer flies over the SoBillboard and peers directly down the Y-axis the results are undefined .

Multiple instances of SoBillboards (DEF/USE) operate as expected - each instance rotates in its unique coordinate system to face the viewer.

FILE FORMAT/DEFAULT

Billboard {

axisOfRotation	0 1 0
useSphereBBox	TRUE

}

NOTE: node available since Open Inventor 10.0

Definition at line 115 of file SoBillboard.h.

Constructor & Destructor Documentation

SoBillboard() [1/2]

SoBillboard::SoBillboard

(

)

Constructor.

SoBillboard() [2/2]

SoBillboard::SoBillboard

(

int

nChildren

)

Constructor that takes approximate number of children.

Member Function Documentation

getClassTypeId()

static SoType SoBillboard::getClassTypeId ( )

static

Returns the type identifier for this class.

getTypeId()

virtual SoType SoBillboard::getTypeId ( ) const

virtual

Returns the type identifier for this specific instance.

Reimplemented from SoSeparator.

Member Data Documentation

axisOfRotation

SoSFVec3f SoBillboard::axisOfRotation

Specifies which axis to use to perform the rotation.

Definition at line 123 of file SoBillboard.h.

useSphereBBox

SoSFBool SoBillboard::useSphereBBox

Specifies if the bounding box returned by SoBillboard::getBoundingBox() method should be extended to completely contain the bounding sphere of the children.

This hint avoids bounding box cache breaks due to rotation of the billboard geometry (which changes the default axis aligned bounding box) and provides a significant performance increase when many SoBillboard nodes are used.

Default is TRUE

Definition at line 135 of file SoBillboard.h.

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The documentation for this class was generated from the following file:

• Inventor/nodes/SoBillboard.h