Iso/iec jtc 1/sc 29 N

Background2D

XSD Description

Functionality and semantics

As defined in ISO/IEC 14496-11 (BIFS), section 7.2.2.18.2.

There exists a Background2D stack, in which the top-most background is the current active background one. The Background2D node allows a background to be displayed behind a 2D scene. The functionality of this node can also be accomplished using other nodes, but use of this node may be more efficient in some implementations. If set_bind is set to TRUE the Background2D is moved to the top of the stack.If set_bind is set to FALSE, the Background2D is removed from the stack so the previous background which is contained in the stack is on top again.

The isBound event is sent as soon as the backdrop is put at the top of the stack, so becoming the current backdrop. The url field specifies the data source to be used (see ISO/IEC 14496-11 , section 7.1.1.2.7.1). The backColor field specifies a colour to be used as the background. This is not a geometry node. The top-left corner of the image is mapped to the top-left corner of the Layer2D and the right-bottom corner of the image is stretched to the right-bottom corner of the Layer2D, regardless of the current transformation. Scaling and/or rotation do not have any effect on this node. The background image will always exactly fill the entire Layer2D, regardless of Layer2D size, without tiling or cropping.

When a Background2D node is included in a 3D context, that is in a Group, Layer3D, or CompositeTexture3D node, then it shall be rendered behind all other geometries and be scaled to fit in the enclosing frame. For Group node, this frame is the whole scene. For Layer3D and CompositeTexture3D the background image is scaled to fit in the frame of the node.

CameraCalibration

XSD Description

BIFS Textual Description

EXTERNPROTO CameraCalibration[

exposedField MFString source []

exposedField SFBool enabled FALSE

exposedField SFTime startTime 0

exposedField SFTime timeBetweenSnapshots 4

exposedField SFInt32 snapshotCount 6

exposedField SFVec2f boardSize 8 5

eventOut SFInt32 onStatus

] "org:mpeg:CameraCalibration"

Functionality and semantics

The exposed field source specifies the URL for the camera for which the calibration is performed.

The exposed field enabled specifies whether the calibration algorithm is executed.

The exposed field startTime specifies at which scene time the calibration algorithm should start running.

The exposed field timeBetweenSnapshots specifies the time between each taken snapshot in seconds.

The exposed field snapshotCount specifies the number of snapshots that will be taken during the calibration procedure.

The exposed field boardSize specifies the number of cross points on the chessboard that is used for calibration.

The eventOut field onStatus outputs the current status of the calibration process as defined below

• 
  1: a snapshot was taken
  
• 
  2: calibration was succesful
  
• 
  -1 calibration was unsuccesful
  

Group

XSD Description

Functionality and semantics

The semantics of the Group node are specified in ISO/IEC 14772-1:1997, section 6.21. ISO/IEC 14496-1 does not support the bounding box parameters (bboxCenter and bboxSize).

Where multiple sub-graphs containing audio content (i.e. Sound nodes) occur as children of a Group node, the sounds shall be combined as described in ISO/IEC 14772-1:1997, section 7.2.2.116.

As specified in ISO/IEC 14772-1:1997, section 6.21. a Group node contains children nodes without introducing a new transformation. It is equivalent to a Transform node containing an identity transform.

More details on the children, addChildren, and removeChildren fields and eventIns can be found in ISO/IEC 14772-1:1997, section 4.6.5, Grouping and children nodes.

The bboxCenter and bboxSize fields specify a bounding box that encloses the Group 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, is calculated by the browser. A description of the bboxCenter and bboxSize fields is contained in ISO/IEC 14772-1:1997, section 4.6.4, Bounding boxes.