SoVRMLScript(3)

NAME
SoVRMLScript - The SoVRMLScript class is used to control the scene using scripts.

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:

SYNOPSIS

#include <Inventor/VRMLnodes/SoVRMLScript.h>

Inherits SoNode.

  Public Member Functions
virtual SoType getTypeId (void) const
virtual void doAction (SoAction *action)
virtual void callback (SoCallbackAction *action)
virtual void GLRender (SoGLRenderAction *action)
virtual void getBoundingBox (SoGetBoundingBoxAction *action)
virtual void pick (SoPickAction *action)
virtual void handleEvent (SoHandleEventAction *action)
virtual void write (SoWriteAction *action)

  Static Public Member Functions
static void initClass (void)
static SoType getClassTypeId (void)
static void setScriptEvaluateCB (SoVRMLScriptEvaluateCB *cb, void *closure)

  Public Attributes
SoMFString url
SoSFBool directOutput
SoSFBool mustEvaluate

  Protected Member Functions
virtual void copyContents (const SoFieldContainer *from, SbBool copyconn)
virtual void notify (SoNotList *list)

  Additional Inherited Members

Detailed Description

The SoVRMLScript class is used to control the scene using scripts.

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:

Script {
  exposedField MFString url           []
  field        SFBool   directOutput  FALSE
  field        SFBool   mustEvaluate  FALSE
  # And any number of:
  eventIn      eventType eventName
  field        fieldType fieldName initialValue
  eventOut     eventType eventName
}

The Script node is used to program behaviour in a scene. Script nodes typically

•   signify a change or user action;

•   receive events from other nodes;

•   contain a program module that performs some computation;

•   effect change somewhere else in the scene by sending events.

Each Script node has associated programming language code, referenced by the url field, that is executed to carry out the Script node's function. That code is referred to as the 'script' in the rest of this description. Details on the url field can be found in 4.5, VRML and the World Wide Web (http://www.web3d.org/x3d/specifications/vrml/ISO-IEC-14772-VRML97/part1/concepts.html#4.5).

Browsers are not required to support any specific language. Detailed information on scripting languages is described in 4.12, Scripting (http://www.web3d.org/x3d/specifications/vrml/ISO-IEC-14772-VRML97/part1/concepts.html#4.12).

Browsers supporting a scripting language for which a language binding is specified shall adhere to that language binding. Sometime before a script receives the first event it shall be initialized (any language-dependent or user-defined initialize() is performed).

The script is able to receive and process events that are sent to it. Each event that can be received shall be declared in the Script node using the same syntax as is used in a prototype definition:

eventIn type name

The type can be any of the standard VRML fields (as defined in 5, Field and event reference). Name shall be an identifier that is unique for this Script node.

The Script node is able to generate events in response to the incoming events. Each event that may be generated shall be declared in the Script node using the following syntax:

eventOut type name

With the exception of the url field, exposedFields are not allowed in Script nodes.

If the Script node's mustEvaluate field is FALSE, the browser may delay sending input events to the script until its outputs are needed by the browser. If the mustEvaluate field is TRUE, the browser shall send input events to the script as soon as possible, regardless of whether the outputs are needed. The mustEvaluate field shall be set to TRUE only if the Script node has effects that are not known to the browser (such as sending information across the network). Otherwise, poor performance may result.

Once the script has access to a VRML node (via an SoSFNode or SoMFNode value either in one of the Script node's fields or passed in as an eventIn), the script is able to read the contents of that node's exposed fields.

If the Script node's directOutput field is TRUE, the script may also send events directly to any node to which it has access, and may dynamically establish or break routes.

If directOutput is FALSE (the default), the script may only affect the rest of the world via events sent through its eventOuts. The results are undefined if directOutput is FALSE and the script sends events directly to a node to which it has access.

A script is able to communicate directly with the VRML browser to get information such as the current time and the current world URL. This is strictly defined by the API for the specific scripting language being used. The location of the Script node in the scene graph has no affect on its operation. For example, if a parent of a Script node is a Switch node with whichChoice set to '-1' (i.e., ignore its children), the Script node continues to operate as specified (i.e., it receives and sends events).

Member Function Documentation

  SoType SoVRMLScript::getTypeId (void) const [virtual]
Returns the type identification of an object derived from a class inheriting SoBase. This is used for run-time type checking and 'downward' casting.

Usage example:

void foo(SoNode * node)
{
  if (node->getTypeId() == SoFile::getClassTypeId()) {
    SoFile * filenode = (SoFile *)node;  // safe downward cast, knows the type
  }
}

For application programmers wanting to extend the library with new nodes, engines, nodekits, draggers or others: this method needs to be overridden in all subclasses. This is typically done as part of setting up the full type system for extension classes, which is usually accomplished by using the pre-defined macros available through for instance Inventor/nodes/SoSubNode.h (SO_NODE_INIT_CLASS and SO_NODE_CONSTRUCTOR for node classes), Inventor/engines/SoSubEngine.h (for engine classes) and so on.

For more information on writing Coin extensions, see the class documentation of the toplevel superclasses for the various class groups.

Implements SoBase.

  void SoVRMLScript::doAction (SoAction * action) [virtual]
This function performs the typical operation of a node for any action.

Reimplemented from SoNode.

  void SoVRMLScript::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 SoNode.

  void SoVRMLScript::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 SoNode.

  void SoVRMLScript::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 SoNode.

  void SoVRMLScript::pick (SoPickAction * action) [virtual]
Action method for SoPickAction.

Does common processing for SoPickAction action instances.

Reimplemented from SoNode.

  void SoVRMLScript::handleEvent (SoHandleEventAction * action) [virtual]
Action method for SoHandleEventAction.

Inspects the event data from action, and processes it if it is something which this node should react to.

Nodes influencing relevant state variables for how event handling is done also overrides this method.

Reimplemented from SoNode.

  void SoVRMLScript::write (SoWriteAction * action) [virtual]
Action method for SoWriteAction.

Writes out a node object, and any connected nodes, engines etc, if necessary.

Reimplemented from SoNode.

  void SoVRMLScript::setScriptEvaluateCB (SoVRMLScriptEvaluateCB * cb, void * closure) [static]
Sets the callback that will be called when the script needs to be evaluated.

  void SoVRMLScript::copyContents (const SoFieldContainer * from, SbBool copyconnections) [protected], [virtual]
Makes a deep copy of all data of from into this instance, except external scenegraph references if copyconnections is FALSE.

This is the protected method that should be overridden by extension node / engine / dragger / whatever subclasses which needs to account for internal data that are not handled automatically.

For copying nodes from application code, you should not invoke this function directly, but rather call the SoNode::copy() function:

SoNode * mynewnode = templatenode->copy();

The same also goes for engines.

Make sure that when you override the copyContents() method in your extension class that you also make it call upwards to it's parent superclass in the inheritance hierarchy, as copyContents() in for instance SoNode and SoFieldContainer does important work. It should go something like this:

void
MyCoinExtensionNode::copyContents(const SoFieldContainer * from,
                                  SbBool copyconnections)
{
  // let parent superclasses do their thing (copy fields, copy
  // instance name, etc etc)
  SoNode::copyContents(from, copyconnections);
  // [..then copy internal data..]
}

Reimplemented from SoNode.

  void SoVRMLScript::notify (SoNotList * l) [protected], [virtual]
Notifies all auditors for this instance when changes are made.

Reimplemented from SoNode.

Author

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