XdkWrl: Anchor Class Reference

6.2 Anchor

The Anchor grouping node retrieves the content of a URL when the user activates (e.g., clicks) some geometry contained within the Anchor node's children. If the URL points to a valid VRML file, that world replaces the world of which the Anchor node is a part (except when the parameter field, described below, alters this behaviour). If non-VRML data is retrieved, the browser shall determine how to handle that data; typically, it will be passed to an appropriate non-VRML browser.

Exactly how a user activates geometry contained by the Anchor node depends on the pointing device and is determined by the VRML browser. Typically, clicking with the pointing device will result in the new scene replacing the current scene. An Anchor node with an empty url does nothing when its children are chosen. A description of how multiple Anchors and pointing-device sensors are resolved on activation is contained in 4.6.7, Sensor nodes.

More details on the children, addChildren, and removeChildren fields and eventIns can be found in 4.6.5, Grouping and children nodes.

The description field in the Anchor node specifies a textual description of the Anchor node. This may be used by browser-specific user interfaces that wish to present users with more detailed information about the Anchor.

The parameter exposed field may be used to supply any additional information to be interpreted by the browser. Each string shall consist of "keyword=value" pairs. For example, some browsers allow the specification of a 'target' for a link to display a link in another part of an HTML document. The parameter field is then:

Anchor { 
  parameter [ "target=name_of_frame" ]
  ...
}

An Anchor node may be used to bind the initial Viewpoint node in a world by specifying a URL ending with "#ViewpointName" where "ViewpointName" is the name of a viewpoint defined in the VRML file. For example:

Anchor { 
  url "http://www.school.edu/vrml/someScene.wrl#OverView"
  children  Shape { geometry Box {} }
}

specifies an anchor that loads the VRML file "someScene.wrl" and binds the initial user view to the Viewpoint node named "OverView" when the Anchor node's geometry (Box) is activated. If the named Viewpoint node is not found in the VRML file, the VRML file is loaded using the default Viewpoint node binding stack rules (see 6.53, Viewpoint).

If the url field is specified in the form "#ViewpointName" (i.e. no file name), the Viewpoint node with the given name ("ViewpointName") in the Anchor's run-time name scope(s) shall be bound (set_bind TRUE). The results are undefined if there are multiple Viewpoints with the same name in the Anchor's run-time name scope(s). The results are undefined if the Anchor node is not part of any run-time name scope or is part of more than one run-time name scope. See 4.4.6, Run-time name scope, for a description of run-time name scopes. See 6.53, Viewpoint, for the Viewpoint transition rules that specify how browsers shall interpret the transition from the old Viewpoint node to the new one. For example:

Anchor { 
  url "#Doorway"
  children Shape { geometry Sphere {} }
}

binds the viewer to the viewpoint defined by the "Doorway" viewpoint in the current world when the sphere is activated. In this case, if the Viewpoint is not found, no action occurs on activation.

More details on the url field are contained in 4.5, VRML and the World Wide Web.

The bboxCenter and bboxSize fields specify a bounding box that encloses the Anchor'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. The default bboxSize value, (-1, -1, -1), implies that the bounding box is not specified and if needed shall be calculated by the browser. More details on the bboxCenter and bboxSize fields can be found in 4.6.4, Bounding boxes.

Constructor & Destructor Documentation

Anchor ( const char * name = "" )

Construct a node with all its fields set to default value, which is equivalent to the code below:

  description = string("");
  bboxCenter.setXYZ(0,0,0);
  bboxSize.setXYZ(-1,-1,-1);

Member Function Documentation

wrl::Node * duplicate ( std::map< const Node *, Node * > & ) const [virtual]

Implements Node.

wrl::Node * duplicate ( ) const [virtual]

Returns a deep copy of this node, that is a fully independant node with all children (if any) also copied. This is mainly useful for instanciating protos.

Implements Node.

wrl::Node::EventInHandle eventIn ( const unsigned int n ) [virtual]

Return a handle on the i th event in of the node or a "unknown" typed handle if there is no such node. Here is how i is related to fields:

0 : addChildren
1 : removeChildren
2 : set_children
3 : set_description
4 : set_parameter
5 : set_url

This function is useful, with nbEventsIn() if you want to traverse all events in of a Node.

Implements Node.

wrl::Node::EventInHandle eventIn ( const std::string & n ) [virtual]

Return a handle on the event in named n of the node or a "unknown" typed handle if there is no such event. Valid names are:

addChildren
removeChildren
set_children
set_description
set_parameter
set_url

Implements Node.

wrl::Node::EventOutHandle eventOut ( const unsigned int n ) [virtual]

Return a handle on the i th event out of the node or a "unknown" typed handle if there is no such node. Here is how i is related to fields:

0 : children_changed
1 : description_changed
2 : parameter_changed
3 : url_changed This function is useful, with nbEventsOut() if you want to traverse all events in of a Node.

Implements Node.

wrl::Node::EventOutHandle eventOut ( const std::string & n ) [virtual]

Return a handle on the event out named n of the node or a "unknown" typed handle if there is no such event. Valid names are:

children_changed
description_changed
parameter_changed
url_changed

Implements Node.

wrl::Node::FieldHandle field ( const unsigned int n ) [virtual]

Return a handle on the i th field of the node or a "unknown" typed handle if there is no such node. Here is how i is related to fields:

0 : children
1 : description
2 : parameter
3 : url
4 : bboxCenter
5 : bboxSize This function is useful, with nbFields() if you want to traverse all fields of a Node.

Implements Node.

wrl::Node::FieldHandle field ( const std::string & n ) [virtual]

Return a handle on the field named n of the node or a "unknown" typed handle if there is no such field. Valid names are:

children
description
parameter
url
bboxCenter
bboxSize

Implements Node.

bool isSetToDefaultValue ( const unsigned int i ) const [virtual]

Implements Node.

unsigned int nbEventsIn ( ) const [inline, virtual]

Returns the number of events in for this node type.

Implements Node.

unsigned int nbEventsOut ( ) const [inline, virtual]

Returns the number of events out for this node type.

Implements Node.

unsigned int nbFields ( ) const [inline, virtual]

Returns the number of fields (exposed or not) for this node type.

Implements Node.

const char * typeName ( ) const [inline, virtual]

Returns "Anchor". Useful for printing.

Implements Node.


Public Member Functions
	Anchor (const char *name="")
virtual	~Anchor ()
virtual unsigned int	nbFields () const
virtual FieldHandle	field (const std::string &n)
virtual FieldHandle	field (const unsigned int i)
virtual bool	isSetToDefaultValue (const unsigned int i) const
virtual unsigned int	nbEventsIn () const
virtual EventInHandle	eventIn (const std::string &n)
virtual EventInHandle	eventIn (const unsigned int i)
virtual unsigned int	nbEventsOut () const
virtual EventOutHandle	eventOut (const std::string &n)
virtual EventOutHandle	eventOut (const unsigned int i)
const char *	typeName () const
virtual Node *	duplicate () const
virtual Node *	duplicate (std::map< const Node , Node > &) const
Public Attributes
Exposed Fields
A field that is capable of receiving events via an eventIn to change its value(s), and generating events via an eventOut when its value(s) change.
MFNode	children
SFString	description
MFString	parameter
MFString	url
Fields
A property or attribute of a node. Each node type has a fixed set of fields. Fields may contain various kinds of data and one or many values. Each field has a default value.
SFVec3f	bboxCenter
SFVec3f	bboxSize
Events In
EventIn< MFNode >	addChildren
EventIn< MFNode >	removeChildren
EventIn< MFNode >	set_children
EventIn< SFString >	set_description
EventIn< MFString >	set_parameter
EventIn< MFString >	set_url
Events Out
EventOut< MFNode >	children_changed
EventOut< SFString >	description_changed
EventOut< MFString >	parameter_changed
EventOut< MFString >	url_changed

Anchor Class Reference
[Standard Node Types]

Public Member Functions

Public Attributes

Detailed Description

6.2 Anchor

Constructor & Destructor Documentation

Member Function Documentation

Member Data Documentation

Anchor Class Reference [Standard Node Types]

Public Member Functions

Public Attributes

Detailed Description

6.2 Anchor

Constructor & Destructor Documentation

Member Function Documentation

Member Data Documentation

Anchor Class Reference
[Standard Node Types]