SoCallbackAction class Reference

This action has mechanisms for tracking traversal position and traversal state. In combination with the ability to pass geometry primitives to callback actions set by the user, this does for instance make it rather straightforward to extract the geometry of a scene graph.

You should be able to use this action for most of your "simple" traversal needs, instead of cooking up your own code, as the SoCallbackAction is rather flexible.

A common use of this action is to extract geometry of non-primitive shapes as triangles. A full-fledged example that demonstrates this on a scenegraph with two spheres follows:

   #include <Inventor/SoDB.h>
   #include <Inventor/SoPrimitiveVertex.h>
   #include <Inventor/actions/SoCallbackAction.h>
   #include <Inventor/nodes/SoCoordinate3.h>
   #include <Inventor/nodes/SoIndexedFaceSet.h>
   #include <Inventor/nodes/SoSeparator.h>
   #include <Inventor/nodes/SoShape.h>
   #include <Inventor/nodes/SoSphere.h>
   #include <Inventor/nodes/SoTranslation.h>


   static SoCoordinate3 * coord3 = NULL;
   static SoIndexedFaceSet * ifs = NULL;

   static int coord3idx = 0;


   static void
   triangle_cb(void * userdata, SoCallbackAction * action,
               const SoPrimitiveVertex * v1,
               const SoPrimitiveVertex * v2,
               const SoPrimitiveVertex * v3)
   {
     const SbVec3f vtx[] = { v1->getPoint(), v2->getPoint(), v3->getPoint() };
     const SbMatrix mm = action->getModelMatrix();

     SbVec3f vx[3];
     for (int j=0; j < 3; j++) { mm.multVecMatrix(vtx[j], vx[j]); }

     // (This is sub-optimal -- should scan for the same vertex
     // coordinates already being present in the SoCoordinate3
     // node. We'll get lots of duplicate coordinates from this.)
     coord3->point.setNum(coord3->point.getNum() + 3);
     coord3->point.setValues(coord3idx, 3, vx);

     int32_t indices[] = { coord3idx, coord3idx + 1, coord3idx + 2, -1 };
     coord3idx += 3;

     int oldsize = ifs->coordIndex.getNum();
     ifs->coordIndex.setNum(oldsize + 4);
     ifs->coordIndex.setValues(oldsize, 4, indices);

     // (Note that it would likely be desirable to grab normal vectors,
     // materials and / or texture coordinates in a real-world
     // application. How to do this is not shown by the above code,
     // but it is not much different from the extraction of vertex
     // coordinates.)
   }


   int
   main(void)
   {
     SoDB::init();

     SoSeparator * root = new SoSeparator;
     root->addChild(new SoSphere);
     SoTranslation * trans = new SoTranslation;
     trans->translation.setValue(10, 0, 0);
     root->addChild(trans);
     SoSphere * ss = new SoSphere;
     ss->radius = 3;
     root->addChild(ss);

     root->ref();

     coord3 = new SoCoordinate3;
     coord3->point.setNum(0);
     ifs = new SoIndexedFaceSet;
     ifs->coordIndex.setNum(0);

     SoCallbackAction ca;
     ca.addTriangleCallback(SoShape::getClassTypeId(), triangle_cb, NULL);
     ca.apply(root);

     root->unref();

     // [the generated SoCoordinate3 and SoIndexedFaceSet nodes would now
     // typically be used in a scenegraph in a viewer, or written to disk
     // or something]

     return 0;
   }

Member Enumeration Documentation

enum SoCallbackAction::Response

Response values for callback function.

Enumeration values:

CONTINUE	Continue traversal as usual.
ABORT	Abort traversal.
PRUNE	Don't do traversal of neither the current node (if returning from a pre-traversal callback) nor its children.

Constructor & Destructor Documentation

SoCallbackAction::SoCallbackAction

(

void

)

Default constructor. Will set the viewport to a standard viewport with size 640x512.

SoCallbackAction::SoCallbackAction

(

const SbViewportRegion &

)

Constructor which lets you specify the viewport.

This constructor is an extension versus the Open Inventor API.

Member Function Documentation

void SoCallbackAction::initClass ( void ) [static]

Initializes the run-time type system for this class, and sets up the enabled elements and action method list.

Reimplemented from SoAction.

void SoCallbackAction::setViewportRegion

(

const SbViewportRegion &

)

Sets the viewport region for this action. When set, the viewport element is initialized right before a traversal starts, making it the current viewport.

This method is an extension versus the Open Inventor API.

Response SoCallbackAction::SoCallbackActionCB	(	void *	userdata,

		SoCallbackAction *	action,

		const SoNode *	node
	)

Callback functions need to be of this type. node is at the current traversal point in the scene graph.

void SoCallbackAction::addPreCallback	(	const SoType	type,

		SoCallbackActionCB *	cb,

		void *	userdata
	)

Set a function cb to call before every node of type is traversed. cb will be called with userdata.

void SoCallbackAction::addPostCallback	(	const SoType	type,

		SoCallbackActionCB *	cb,

		void *	userdata
	)

Set a function cb to call after every node of type has been traversed. cb will be called with userdata.

void SoCallbackAction::addPreTailCallback	(	SoCallbackActionCB *	cb,

		void *	userdata
	)

Set a function cb to call before the tail of a path is traversed. cb will be called with userdata.

void SoCallbackAction::addPostTailCallback	(	SoCallbackActionCB *	cb,

		void *	userdata
	)

Set a function cb to call after the tail of a path has been traversed. cb will be called with userdata.

void SoCallbackAction::addTriangleCallback	(	const SoType	type,

		SoTriangleCB *	cb,

		void *	userdata
	)

Set a function cb to call when traversing a node of type which generates triangle primitives for rendering. cb will be called with userdata.

void SoCallbackAction::addLineSegmentCallback	(	const SoType	type,

		SoLineSegmentCB *	cb,

		void *	userdata
	)

Set a function cb to call when traversing a node of type which generates line primitives for rendering. cb will be called with userdata.

void SoCallbackAction::addPointCallback	(	const SoType	type,

		SoPointCB *	cb,

		void *	userdata
	)

Set a function cb to call when traversing a node of type which generates single point primitives for rendering. cb will be called with userdata.

SoDecimationTypeElement::Type SoCallbackAction::getDecimationType

(

void

)

const

Returns current decimation type setting.

float SoCallbackAction::getDecimationPercentage

(

void

)

const

Returns current decimation percentage setting.

float SoCallbackAction::getComplexity

(

void

)

const

Returns current complexity setting.

SoComplexity::Type SoCallbackAction::getComplexityType

(

void

)

const

Returns current complexity type setting.

int32_t SoCallbackAction::getNumCoordinates

(

void

)

const

Returns current number of coordinates in the state.

const SbVec3f & SoCallbackAction::getCoordinate3

(

const int

index

)

const

Returns a coordinate triplet from the current state pool of coordinates.

const SbVec4f & SoCallbackAction::getCoordinate4

(

const int

index

)

const

Returns a coordinate quartuplet from the current state pool of coordinates.

SoDrawStyle::Style SoCallbackAction::getDrawStyle

(

void

)

const

Returns current draw style setting.

unsigned short SoCallbackAction::getLinePattern

(

void

)

const

Returns current line pattern setting.

float SoCallbackAction::getLineWidth

(

void

)

const

Returns current line width setting.

float SoCallbackAction::getPointSize

(

void

)

const

Returns current point size setting.

const SbName & SoCallbackAction::getFontName

(

void

)

const

Returns current fontname setting.

float SoCallbackAction::getFontSize

(

void

)

const

Returns current fontsize setting.

SoLightModel::Model SoCallbackAction::getLightModel

(

void

)

const

Returns current lightmodel setting.

const SbVec3f & SoCallbackAction::getLightAttenuation

(

void

)

const

Returns current light attenuation setting.

void SoCallbackAction::getMaterial	(	SbColor &	ambient,

		SbColor &	diffuse,

		SbColor &	specular,

		SbColor &	emission,

		float &	shininess,

		float &	transparency,

		const int	index = 0
	)	const

Returns current material settings.

SoMaterialBinding::Binding SoCallbackAction::getMaterialBinding

(

void

)

const

Returns current materialbinding setting.

uint32_t SoCallbackAction::getNumNormals

(

void

)

const

Returns current number of normals in the state.

const SbVec3f & SoCallbackAction::getNormal

(

const int

index

)

const

Returns the normal vectors at index from the current state.

SoNormalBinding::Binding SoCallbackAction::getNormalBinding

(

void

)

const

Returns current normalbinding setting.

int32_t SoCallbackAction::getNumProfileCoordinates

(

void

)

const

Returns current number of profile coordinates in the state.

const SbVec2f & SoCallbackAction::getProfileCoordinate2

(

const int

index

)

const

Returns current number of SbVec2f profile coordinates in the state.

const SbVec3f & SoCallbackAction::getProfileCoordinate3

(

const int

index

)

const

Returns current number of SbVec3f profile coordinates in the state.

const SoNodeList & SoCallbackAction::getProfile

(

void

)

const

Returns current list of profile nodes.

SoShapeHints::VertexOrdering SoCallbackAction::getVertexOrdering

(

void

)

const

Returns current vertexordering shapehint setting.

SoShapeHints::ShapeType SoCallbackAction::getShapeType

(

void

)

const

Returns current shapetype hint setting.

SoShapeHints::FaceType SoCallbackAction::getFaceType

(

void

)

const

Returns current facetype hint setting.

float SoCallbackAction::getCreaseAngle

(

void

)

const

Returns current creaseangle setting.

int32_t SoCallbackAction::getNumTextureCoordinates

(

void

)

const

Returns current number of texture coordinates in the traversal state.

const SbVec2f & SoCallbackAction::getTextureCoordinate2

(

const int

index

)

const

Returns SbVec2f texture coordinate at index from the texture coordinate pool of the traversal state.

const SbVec4f & SoCallbackAction::getTextureCoordinate4

(

const int

index

)

const

Returns SbVec4f texture coordinate at index from the texture coordinate pool of the traversal state.

SoTextureCoordinateBinding::Binding SoCallbackAction::getTextureCoordinateBinding

(

void

)

const

Returns current texturecoordinate binding setting.

const SbColor & SoCallbackAction::getTextureBlendColor

(

void

)

const

Returns current texture blend color setting.

const unsigned char * SoCallbackAction::getTextureImage	(	SbVec2s &	size,

		int &	numcomps
	)	const

Returns current texture image settings.

const SbMatrix & SoCallbackAction::getTextureMatrix

(

void

)

const

Returns current texture transformation matrix setting.

SoTexture2::Model SoCallbackAction::getTextureModel

(

void

)

const

Returns current texturemapping model setting.

SoTexture2::Wrap SoCallbackAction::getTextureWrapS

(

void

)

const

Returns current texture wrapping setting for the S coordinate.

SoTexture2::Wrap SoCallbackAction::getTextureWrapT

(

void

)

const

Returns current texture wrapping setting for the T coordinate.

const SbMatrix & SoCallbackAction::getModelMatrix

(

void

)

const

Returns current model matrix.

SoUnits::Units SoCallbackAction::getUnits

(

void

)

const

Returns current units setting.

float SoCallbackAction::getFocalDistance

(

void

)

const

Returns current camera focal distance setting.

const SbMatrix & SoCallbackAction::getProjectionMatrix

(

void

)

const

Returns current projection matrix.

const SbMatrix & SoCallbackAction::getViewingMatrix

(

void

)

const

Returns current viewing matrix.

const SbViewVolume & SoCallbackAction::getViewVolume

(

void

)

const

Returns current view volume setting.

const SbViewportRegion & SoCallbackAction::getViewportRegion

(

void

)

const

Returns current viewport region setting.

This method is an extension versus the Open Inventor API.

SoPickStyle::Style SoCallbackAction::getPickStyle

(

void

)

const

Returns current pickstyle setting.

int32_t SoCallbackAction::getSwitch

(

void

)

const

Returns last SoSwitch::whichChild setting during the traversal.

void SoCallbackAction::invokePreCallbacks

(

const SoNode *const

node

)

For internal use only.

void SoCallbackAction::invokePostCallbacks

(

const SoNode *const

node

)

For internal use only.

void SoCallbackAction::invokeLineSegmentCallbacks	(	const SoShape *const	shape,

		const SoPrimitiveVertex *const	v1,

		const SoPrimitiveVertex *const	v2
	)

For internal use only.

void SoCallbackAction::invokePointCallbacks	(	const SoShape *const	shape,

		const SoPrimitiveVertex *const	v
	)

For internal use only.

SbBool SoCallbackAction::shouldGeneratePrimitives

(

const SoShape *

shape

)

const

For internal use only.

SoNode * SoCallbackAction::getCurPathTail ( void ) [virtual]

Returns the current tail of the traversal path for the callback action.

Reimplemented from SoAction.

void SoCallbackAction::setCurrentNode

(

SoNode *const

node

)

Used from nodes during traversal to keep a current node pointer in the action.

void SoCallbackAction::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.

Public Types
enum	Response { CONTINUE, ABORT, PRUNE }
Public Methods
	SoCallbackAction (void)
	SoCallbackAction (const SbViewportRegion &vp)
virtual	~SoCallbackAction ()
void	setViewportRegion (const SbViewportRegion &vp)
typedef Response	SoCallbackActionCB (void userdata, SoCallbackAction action, const SoNode *node)
void	addPreCallback (const SoType type, SoCallbackActionCB cb, void userdata)
void	addPostCallback (const SoType type, SoCallbackActionCB cb, void userdata)
void	addPreTailCallback (SoCallbackActionCB cb, void userdata)
void	addPostTailCallback (SoCallbackActionCB cb, void userdata)
void	addTriangleCallback (const SoType type, SoTriangleCB cb, void userdata)
void	addLineSegmentCallback (const SoType type, SoLineSegmentCB cb, void userdata)
void	addPointCallback (const SoType type, SoPointCB cb, void userdata)
SoDecimationTypeElement::Type	getDecimationType (void) const
float	getDecimationPercentage (void) const
float	getComplexity (void) const
SoComplexity::Type	getComplexityType (void) const
int32_t	getNumCoordinates (void) const
const SbVec3f &	getCoordinate3 (const int index) const
const SbVec4f &	getCoordinate4 (const int index) const
SoDrawStyle::Style	getDrawStyle (void) const
unsigned short	getLinePattern (void) const
float	getLineWidth (void) const
float	getPointSize (void) const
const SbName &	getFontName (void) const
float	getFontSize (void) const
SoLightModel::Model	getLightModel (void) const
const SbVec3f &	getLightAttenuation (void) const
void	getMaterial (SbColor &ambient, SbColor &diffuse, SbColor &specular, SbColor &emission, float &shininess, float &transparency, const int index=0) const
SoMaterialBinding::Binding	getMaterialBinding (void) const
uint32_t	getNumNormals (void) const
const SbVec3f &	getNormal (const int index) const
SoNormalBinding::Binding	getNormalBinding (void) const
int32_t	getNumProfileCoordinates (void) const
const SbVec2f &	getProfileCoordinate2 (const int index) const
const SbVec3f &	getProfileCoordinate3 (const int index) const
const SoNodeList &	getProfile (void) const
SoShapeHints::VertexOrdering	getVertexOrdering (void) const
SoShapeHints::ShapeType	getShapeType (void) const
SoShapeHints::FaceType	getFaceType (void) const
float	getCreaseAngle (void) const
int32_t	getNumTextureCoordinates (void) const
const SbVec2f &	getTextureCoordinate2 (const int index) const
const SbVec4f &	getTextureCoordinate4 (const int index) const
SoTextureCoordinateBinding::Binding	getTextureCoordinateBinding (void) const
const SbColor &	getTextureBlendColor (void) const
const unsigned char *	getTextureImage (SbVec2s &size, int &numcomps) const
const SbMatrix &	getTextureMatrix (void) const
SoTexture2::Model	getTextureModel (void) const
SoTexture2::Wrap	getTextureWrapS (void) const
SoTexture2::Wrap	getTextureWrapT (void) const
const SbMatrix &	getModelMatrix (void) const
SoUnits::Units	getUnits (void) const
float	getFocalDistance (void) const
const SbMatrix &	getProjectionMatrix (void) const
const SbMatrix &	getViewingMatrix (void) const
const SbViewVolume &	getViewVolume (void) const
const SbViewportRegion &	getViewportRegion (void) const
SoPickStyle::Style	getPickStyle (void) const
int32_t	getSwitch (void) const
Response	getCurrentResponse (void) const
void	invokePreCallbacks (const SoNode *const node)
void	invokePostCallbacks (const SoNode *const node)
void	invokeTriangleCallbacks (const SoShape const shape, const SoPrimitiveVertex const v1, const SoPrimitiveVertex const v2, const SoPrimitiveVertex const v3)
void	invokeLineSegmentCallbacks (const SoShape const shape, const SoPrimitiveVertex const v1, const SoPrimitiveVertex *const v2)
void	invokePointCallbacks (const SoShape const shape, const SoPrimitiveVertex const v)
SbBool	shouldGeneratePrimitives (const SoShape *shape) const
virtual SoNode *	getCurPathTail (void)
void	setCurrentNode (SoNode *const node)
Static Public Methods
void	initClass (void)
Protected Methods
virtual void	beginTraversal (SoNode *node)

SoCallbackAction Class Reference

Public Types

Public Methods

Static Public Methods

Protected Methods

Detailed Description

Member Enumeration Documentation

Constructor & Destructor Documentation

Member Function Documentation