Open Inventor Release 2023.2.3
 
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SoBillboard Class Reference

VSG extension 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 SoNodegetChild (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 SoNodecopy (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 SoFieldgetField (const SbName &fieldName) const
 Returns a the field of this object whose name is fieldName.
 
virtual SoFieldgetEventIn (const SbName &fieldName) const
 Returns a the eventIn with the given name.
 
virtual SoFieldgetEventOut (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 SoNodegetByName (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...
 

Detailed Description

VSG extension 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

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.


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