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SoVRMLBillboard Class Reference
[VRML97 classes]

#include <Inventor/VRMLnodes/SoVRMLBillboard.h>

Inheritance diagram for SoVRMLBillboard:

SoVRMLParent SoGroup SoNode SoFieldContainer SoBase List of all members.

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:

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:

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/technicalinfo/specifications/vrml97/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/technicalinfo/specifications/vrml97/part1/concepts.html#4.6.4>),


Public Member Functions

 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)

Static Public Member Functions

void initClass (void)

Public Attributes

SoSFVec3f axisOfRotation
SoSFVec3f bboxCenter
SoSFVec3f bboxSize

Protected Member Functions

virtual ~SoVRMLBillboard ()


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

void SoVRMLBillboard::initClass void   )  [static]
 

Sets up initialization for data common to all instances of this class, like submitting necessary information to the Coin type system.

Reimplemented from SoVRMLParent.

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.

Reimplemented from SoGroup.

void SoVRMLBillboard::GLRender SoGLRenderAction action  )  [virtual]
 

Action method for the SoGLRenderAction.

This is called during rendering traversals. Nodes influencing the rendering state in any way or who wants to throw geometry primitives at OpenGL overrides this method.

Reimplemented from SoGroup.

void SoVRMLBillboard::getBoundingBox SoGetBoundingBoxAction action  )  [virtual]
 

Action method for the SoGetBoundingBoxAction.

Calculates bounding box and center coordinates for node and modifies the values of the action to encompass the bounding box for this node and to shift the center point for the scene more towards the one for this node.

Nodes influencing how geometry nodes calculates their bounding box also overrides this method to change the relevant state variables.

Reimplemented from SoGroup.

void SoVRMLBillboard::getMatrix SoGetMatrixAction action  )  [virtual]
 

Action method for SoGetMatrixAction.

Updates action by accumulating with the transformation matrix of this node (if any).

Reimplemented from SoGroup.

void SoVRMLBillboard::pick SoPickAction action  )  [virtual]
 

Action method for SoPickAction.

Does common processing for SoPickAction action instances.

Reimplemented from SoGroup.

void SoVRMLBillboard::search SoSearchAction action  )  [virtual]
 

Action method for SoSearchAction.

Compares the search criteria from the action to see if this node is a match. Searching is done by matching up all criteria set up in the SoSearchAction -- if any of the requested criteria is a miss, the search is not deemed successful for the node.

See also:
SoSearchAction

Reimplemented from SoVRMLParent.

void SoVRMLBillboard::GLRenderBelowPath SoGLRenderAction action  )  [virtual]
 

Implements the SoAction::BELOW_PATH traversal method for the rendering action.

Reimplemented from SoNode.

void SoVRMLBillboard::GLRenderInPath SoGLRenderAction action  )  [virtual]
 

Implements the SoAction::IN_PATH traversal method for the rendering action.

Reimplemented from SoNode.

void SoVRMLBillboard::GLRenderOffPath SoGLRenderAction action  )  [virtual]
 

Implements the SoAction::OFF_PATH traversal method for the rendering action.

Reimplemented from SoNode.

void SoVRMLBillboard::notify SoNotList list  )  [virtual]
 

Notifies all auditors for this instance when changes are made.

Reimplemented from SoVRMLParent.


Member Data Documentation

SoSFVec3f SoVRMLBillboard::axisOfRotation
 

The axis of rotation for the geometry.

SoSFVec3f SoVRMLBillboard::bboxCenter
 

The bounding box center hint. Default value is (0, 0, 0).

SoSFVec3f SoVRMLBillboard::bboxSize
 

The bounding box size hint. Default value is (-1, -1, -1).


The documentation for this class was generated from the following files:
Generated on Sat Jan 22 10:48:44 2005 for Coin by doxygen 1.3.6