SoGetMatrixAction(3)

NAME
SoGetMatrixAction - The SoGetMatrixAction class is an action for accumulating the transformation matrix of a subgraph.

This action makes it easy to calculate and convert to and from the global coordinate system of your scene and local coordinates of parts in a hierarchical model.

SYNOPSIS

#include <Inventor/actions/SoGetMatrixAction.h>

Inherits SoAction.

  Public Member Functions
virtual SoType getTypeId (void) const
SoGetMatrixAction (const SbViewportRegion &region)
virtual ~SoGetMatrixAction (void)
void setViewportRegion (const SbViewportRegion &region)
const SbViewportRegion & getViewportRegion (void) const
SbMatrix & getMatrix (void)
SbMatrix & getInverse (void)
SbMatrix & getTextureMatrix (void)
SbMatrix & getTextureInverse (void)

  Static Public Member Functions
static SoType getClassTypeId (void)
static void addMethod (const SoType type, SoActionMethod method)
static void enableElement (const SoType type, const int stackindex)
static void initClass (void)

  Protected Member Functions
virtual const SoEnabledElementsList & getEnabledElements (void) const
virtual void beginTraversal (SoNode *node)

  Static Protected Member Functions
static SoEnabledElementsList * getClassEnabledElements (void)
static SoActionMethodList * getClassActionMethods (void)

  Additional Inherited Members

Detailed Description

The SoGetMatrixAction class is an action for accumulating the transformation matrix of a subgraph.

This action makes it easy to calculate and convert to and from the global coordinate system of your scene and local coordinates of parts in a hierarchical model. As opposed to most other action types, the SoGetMatrixAction does not traverse children of the node it is applied to -- just the node itself. When applied to paths, it stops at the last node and does not continue further with the children of the tail node.

Typical usage when querying for world space position, orientation and/or scaling would be as follows:

// First get hold of an SoPath through the scenegraph down to the
// node ("mynode") you want to query about its current world space
// transformation(s).
SoSearchAction * searchaction = new SoSearchAction;
searchaction->setNode(mynode);
searchaction->apply(myscenegraphroot);
SoPath * path = searchaction->getPath();
assert(path != NULL);
// Then apply the SoGetMatrixAction to get the full transformation
// matrix from world space.
const SbViewportRegion vpr = myviewer->getViewportRegion();
SoGetMatrixAction * getmatrixaction = new SoGetMatrixAction(vpr);
getmatrixaction->apply(path);
SbMatrix transformation = getmatrixaction->getMatrix();
// And if you want to access the individual transformation
// components of the matrix:
SbVec3f translation;
SbRotation rotation;
SbVec3f scalevector;
SbRotation scaleorientation;
transformation.getTransform(translation, rotation, scalevector, scaleorientation);

Constructor & Destructor Documentation

  SoGetMatrixAction::SoGetMatrixAction (const SbViewportRegion & region)
Constructor.

The region viewport specification is not used by this action, and is passed along in case it is needed by any nodes.

  SoGetMatrixAction::~SoGetMatrixAction (void) [virtual]
Destructor.

Member Function Documentation

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

Usage example:

void bar(SoAction * action)
{
  if (action->getTypeId() == SoGLRenderAction::getClassTypeId()) {
    // safe downward cast, know the type
    SoGLRenderAction * glrender = (SoGLRenderAction *)action;
  }
  return; // ignore if not renderaction
}

For application programmers wanting to extend the library with new actions: 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 Inventor/nodes/SoSubAction.h: SO_ACTION_SOURCE, SO_ACTION_INIT_CLASS and SO_ACTION_CONSTRUCTOR.

For more information on writing Coin extensions, see the SoAction class documentation.

Returns the actual type id of an object derived from a class inheriting SoAction. Needs to be overridden in all subclasses.

Implements SoAction.

  void SoGetMatrixAction::addMethod (const SoType type, SoActionMethod method) [static]
This API member is considered internal to the library, as it is not likely to be of interest to the application programmer.

  void SoGetMatrixAction::enableElement (const SoType type, const int stackindex) [static]
This API member is considered internal to the library, as it is not likely to be of interest to the application programmer.

  const SoEnabledElementsList & SoGetMatrixAction::getEnabledElements (void) const [protected], [virtual]
Returns a list of the elements used by action instances of this class upon traversal operations.

Reimplemented from SoAction.

  void SoGetMatrixAction::setViewportRegion (const SbViewportRegion & region)
Set the viewport region.

See also:
    SoGetMatrixAction::SoGetMatrixAction()

  const SbViewportRegion & SoGetMatrixAction::getViewportRegion (void) const
Returns the viewport region for the action instance.

  SbMatrix & SoGetMatrixAction::getMatrix (void)
Returns the accumulated transformation matrix.

Note: don't modify the returned matrix. This should only be done if you are implementing your own transformation type node extensions. This advice is also valid for the other matrix access methods documented below.

  SbMatrix & SoGetMatrixAction::getInverse (void)
Returns the inverse of the accumulated transformation matrix.

  SbMatrix & SoGetMatrixAction::getTextureMatrix (void)
Returns the accumulated texture matrix.

  SbMatrix & SoGetMatrixAction::getTextureInverse (void)
Returns the inverse of the accumulated texture matrix.

  void SoGetMatrixAction::beginTraversal (SoNode * node) [protected], [virtual]
This virtual method is called from SoAction::apply(), and is the entry point for the actual scenegraph traversal.

It can be overridden to initialize the action at traversal start, for specific initializations in the action subclasses inheriting SoAction.

Default method just calls traverse(), which any overridden implementation of the method must do too (or call SoAction::beginTraversal()) to trigger the scenegraph traversal.

Reimplemented from SoAction.

Author

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