Iso/iec jtc 1/sc 29 N

Inline

XSD Description

Functionality and semantics

As specified in ISO/IEC 14772-1:1997, section 6.25.

The Inline node is a grouping node that reads its children data from a location in the World Wide Web. Exactly when its children are read and displayed is not defined (e.g. reading the children may be delayed until the Inline node's bounding box is visible to the viewer). The url field specifies the URL containing the children. An Inline node with an empty URL does nothing.

Each specified URL shall refer to a valid VRML file that contains a list of children nodes, prototypes, and routes at the top level as described in 4.6.5, Grouping and children nodes. The results are undefined if the URL refers to a file that is not VRML or if the VRML file contains non-children nodes at the top level.

If multiple URLs are specified, the browser may display a URL of a lower preference VRML file while it is obtaining, or if it is unable to obtain, the higher preference VRML file.

The results are undefined if the contents of the URL change after it has been loaded.

The bboxCenter and bboxSize fields specify a bounding box that encloses the Inline 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.

Layer2D

XSD Description

Functionality and semantics

As defined in ISO/IEC 14496-11 (BIFS), section 7.2.2.72.2.

The Layer2D node is a transparent rendering rectangle region on the screen where a 2D scene is drawn. The rectangle always faces the viewer of the scene. Layer2D and Layer3D nodes enable the composition of multiple 2D and 3D scenes. EXAMPLE: This allows users to have 2D interfaces to a 2D scene, or 3D interfaces to a 2D scene, or to view a 3D scene from different viewpoints in the same scene.

The addChildren eventIn specifies a list of 2D nodes that shall be added to the Layer2D’s children field. The removeChildren eventIn specifies a list of 2D nodes that shall be removed from the Layer2D's children field. The children field may contain any 2D children nodes that define a 2D scene. Layer nodes are considered to be 2D objects within the scene. The layering of the 2D and 3D layers is specified by any relevant transformations in the scene graph. The Layer2D node is composed with its center at the origin of the local coordinate system and shall not be present in 3D contexts (see ISO/IEC 14496-11, section 7.1.1.2.1).

The size parameter shall be a floating point number that expresses the width and height of the layer in the units of the local coordinate system. In case of a layer at the root of the hierarchy, the size is expressed in terms of the default 2D coordinate system (see ISO/IEC 14496-11, section 7.1.1.2.2). A size of -1 in either direction, means that the Layer2D node is not specified in size in that direction, and that the size is adjusted to the size of the parent layer, or the global rendering area dimension if the layer is on the top of the hierarchy. In the case where a 2D scene or object is shared between several Layer2D nodes, the behaviours are defined exactly as for objects that are multiply referenced using the DEF/USE mechanism. A sensor triggers an event whenever the sensor is triggered in any of the Layer2D in which it is contained. The behaviors triggered by the shared sensors as well as other behaviors that apply on objects shared between several layers apply on all layers containing these objects.

A Layer2D stores the stack of bindable children nodes that can affect the children scene of the layer. All relevant bindable children nodes have a corresponding exposedField in the Layer2D node. During presentation, these fields take the value of the currently bound bindable children node for the scene that is a child of the Layer2D node. Initially, the bound bindable children node is the corresponding field value of the Layer2D node if it is defined. If the field is undefined, the first bindable children node defined in the child scene will be bound. When the binding mechanism of the bindable children node is used (set_bind field set to TRUE), all the parent layers containing this node set the corresponding field to the current bound node value. It is therefore possible to share scenes across layers, and to have different bound nodes active, or to trigger a change of bindable children node for all layers containing a given bindable children node. For 2D scenes, the background field specifies the bound Background2D node. The viewport field is reserved for future extensions for 2D scenes.

All the 2D objects contained in a single Layer2D node form a single composed object. This composed object is considered by other elements of the scene to be a single object. In other words, if a Layer2D node, A, is the parent of two objects, B and C, layered one on top of the other, it will not be possible to insert a new object, D, between B and C unless D is added as a child of A.

Layers are transparent to user input if the background field is set to NULL. If the background field is specified, any transparent part of the background will also let user input through to lower layers.