osgShadow::ViewDependentShadowTechnique Class Reference

#include <ViewDependentShadowTechnique.h>

Inheritance diagram for osgShadow::ViewDependentShadowTechnique:

Collaboration diagram for osgShadow::ViewDependentShadowTechnique:

Classes
struct	ViewData

Public Member Functions
	ViewDependentShadowTechnique (void)
	ViewDependentShadowTechnique (const ViewDependentShadowTechnique &vdst, const osg::CopyOp &copyop=osg::CopyOp::SHALLOW_COPY)
	META_Object (osgShadow, ViewDependentShadowTechnique)
virtual void	dirty ()
virtual void	init ()
virtual void	update (osg::NodeVisitor &nv)
virtual void	cull (osgUtil::CullVisitor &cv)
virtual void	cleanSceneGraph ()
virtual void	traverse (osg::NodeVisitor &nv)
Public Member Functions inherited from osgShadow::ShadowTechnique
	ShadowTechnique ()
	ShadowTechnique (const ShadowTechnique &es, const osg::CopyOp &copyop=osg::CopyOp::SHALLOW_COPY)
	META_Object (osgShadow, ShadowTechnique)
ShadowedScene *	getShadowedScene ()
const ShadowedScene *	getShadowedScene () const
Public Member Functions inherited from osg::Object
	Object ()
	Object (bool threadSafeRefUnref)
	Object (const Object &, const CopyOp &copyop=CopyOp::SHALLOW_COPY)
virtual Object *	cloneType () const =0
virtual Object *	clone (const CopyOp &) const =0
virtual bool	isSameKindAs (const Object *) const
virtual const char *	libraryName () const =0
virtual const char *	className () const =0
std::string	getCompoundClassName () const
virtual Node *	asNode ()
virtual const Node *	asNode () const
virtual NodeVisitor *	asNodeVisitor ()
virtual const NodeVisitor *	asNodeVisitor () const
virtual StateAttribute *	asStateAttribute ()
virtual const StateAttribute *	asStateAttribute () const
virtual Uniform *	asUniform ()
virtual const Uniform *	asUniform () const
virtual void	setThreadSafeRefUnref (bool threadSafe)
virtual void	setName (const std::string &name)
void	setName (const char *name)
const std::string &	getName () const
void	setDataVariance (DataVariance dv)
DataVariance	getDataVariance () const
virtual void	computeDataVariance ()
void	setUserDataContainer (osg::UserDataContainer *udc)
osg::UserDataContainer *	getUserDataContainer ()
const osg::UserDataContainer *	getUserDataContainer () const
osg::UserDataContainer *	getOrCreateUserDataContainer ()
virtual void	setUserData (Referenced *obj)
virtual Referenced *	getUserData ()
virtual const Referenced *	getUserData () const
template<typename T >
bool	getUserValue (const std::string &name, T &value) const
template<typename T >
void	setUserValue (const std::string &name, const T &value)
virtual void	resizeGLObjectBuffers (unsigned int)
virtual void	releaseGLObjects (osg::State *=0) const
template<typename T >
BoolValueObject UCharValueObject UShortValueObject UIntValueObject DoubleValueObject Vec3fValueObject Vec2dValueObject Vec4dValueObject PlaneValueObject MatrixdValueObject BoundingBoxdValueObject BoundingSpheredValueObject bool	getUserValue (const std::string &name, T &value) const
Public Member Functions inherited from osg::Referenced
	Referenced ()
	Referenced (bool threadSafeRefUnref)
	Referenced (const Referenced &)
Referenced &	operator= (const Referenced &)
bool	getThreadSafeRefUnref () const
OpenThreads::Mutex *	getRefMutex () const
int	ref () const
int	unref () const
int	unref_nodelete () const
int	referenceCount () const
ObserverSet *	getObserverSet () const
ObserverSet *	getOrCreateObserverSet () const
void	addObserver (Observer *observer) const
void	removeObserver (Observer *observer) const

Protected Types
typedef std::map< osg::ref_ptr < osgUtil::CullVisitor > , osg::ref_ptr< ViewData > >	ViewDataMap

Protected Member Functions
	~ViewDependentShadowTechnique (void)
virtual ViewDependentShadowTechnique::ViewData *	getViewDependentData (osgUtil::CullVisitor *cv)
virtual void	setViewDependentData (osgUtil::CullVisitor *cv, ViewDependentShadowTechnique::ViewData *data)
Protected Member Functions inherited from osgShadow::ShadowTechnique
osg::Vec3	computeOrthogonalVector (const osg::Vec3 &direction) const
virtual	~ShadowTechnique ()
Protected Member Functions inherited from osg::Object
virtual	~Object ()
Protected Member Functions inherited from osg::Referenced
virtual	~Referenced ()
void	signalObserversAndDelete (bool signalDelete, bool doDelete) const
void	deleteUsingDeleteHandler () const

Protected Attributes
ViewDataMap	_viewDataMap
OpenThreads::Mutex	_viewDataMapMutex
Protected Attributes inherited from osgShadow::ShadowTechnique
ShadowedScene *	_shadowedScene
bool	_dirty
Protected Attributes inherited from osg::Object
std::string	_name
DataVariance	_dataVariance
osg::UserDataContainer *	_userDataContainer
Protected Attributes inherited from osg::Referenced
OpenThreads::AtomicPtr	_observerSet
OpenThreads::Atomic	_refCount

Additional Inherited Members
Public Types inherited from osg::Object
enum	DataVariance { DYNAMIC, STATIC, UNSPECIFIED }
Static Public Member Functions inherited from osg::Referenced
static OpenThreads::Mutex *	getGlobalReferencedMutex ()
static void	setThreadSafeReferenceCounting (bool enableThreadSafeReferenceCounting)
static bool	getThreadSafeReferenceCounting ()
static void	setDeleteHandler (DeleteHandler *handler)
static DeleteHandler *	getDeleteHandler ()

Detailed Description

ViewDependentShadowTechnique is a base class for all View Dependent Shadow techniques. It defines fundamental object structure and methods to manage separate shadow resources for each view of the scene. By view we understand osg::View or SceneView instance and their associated Camera. Typical osg application has one or more such views. View Dependent Shadow techniques manage shadow generation for them.

View Dependent Shadow techniques are used to optimize shadow algorithms for part of the scene seen on the view. If rest of the scene is behind view frustum, there is no sense in computing shadows for it. Since in practice we often use 3d databases extending far beyond current camera frustum View Dependent Shadow approach may produce much better shadows.

The other goal is to provide framework for thread safe rendering of the shadows. It allows to use shadows with different OSG threading models.

Conceptually ViewDependentShadowTechnique is similar to osgSim::OverlayNode. Its a container class for number of ViewData (or ViewData derived) objects doing actual shadow work for each of the scene views.

But ViewDependentShadowTechnique is intended as foundation layer for all derived classes so in some way it extends osgSim::OverlayNode approach a bit.

HOW IT WORKS:

ViewDependendentShadowTechnique is derived from osgShadow::ShadowTechnique and as such overrides virtual methods of osgShadow::ShadowTechnique. But most of the shadow dirty work is done by ViewData objects, ViewDependendentShadowTechnique::cull is the only osgShadow::ShadowTechnique method where ViewDependendentShadowTechnique does something significant:

What ViewDependentShadowTechnique::cull( CullVisitor & cv ) does ? It identifies View. CullVisitor ptr is used as View identificator. In practice we do not check and interpret what are actual Views and SceneViews set up by application. We focus on Camera and CullVisitors as a identificators of views. We can safely do this because each such view will have associated unique CullVisitor used to cull the scene in every frame.

Based on CullVisitor ptr passed to cull method, associated Technique::ViewData object is created (if necessary) and then seleced. Then control is passed to this ViewData object. So, each view has its associated unique ViewData (or derived) object performing dirty work of shadow resources management and shadow generation for the view.

To support creation of classes derived from ViewDependentShadowTechnique it was necessary to provide mechanism to override ViewData and allow for initialization of new derived ViewData objects. Creation and initialization is performed when ViewDependendentShadowTechnique::cull gets called with CullVistor ptr which does not yet have associated ViewData object. When it happens, virtual initViewDependentData method is called to give derived techniques a chance to allocate and iniitalize its specific resources as new ViewData derived instance. In practice initViewDependentData in derived techniques should look the same as in base class so as a convenience it was defined as META_ViewDependentShadowTechnique macro. Derived techniques use this macro to override initViewDependentData method for their usage.

After ViewData derived object is construted and selected, control is passed to this object by call to virtual ViewData::cull method. The rest of work is the done by this object. ViewDependentShadowTechnique::ViewData is intended as a base class so it does nothing. In practice the rest of dirty work will do new ViewData classes implemented in derived techniques.

Definition at line 104 of file ViewDependentShadowTechnique.h.

Member Typedef Documentation

typedef std::map< osg::ref_ptr< osgUtil::CullVisitor >, osg::ref_ptr< ViewData > > osgShadow::ViewDependentShadowTechnique::ViewDataMap

protected

Map of view dependent data per view cull visitor (CVs are used as indices) ViewDependentShadowTechnique uses this map to find VieData for each cull vitior

Definition at line 207 of file ViewDependentShadowTechnique.h.

Constructor & Destructor Documentation

osgShadow::ViewDependentShadowTechnique::ViewDependentShadowTechnique

(

void

)

osgShadow::ShadowTechnique equivalent methods for view dependent techniquesClassic OSG constructor

osgShadow::ViewDependentShadowTechnique::ViewDependentShadowTechnique	(	const ViewDependentShadowTechnique &	vdst,
		const osg::CopyOp &	copyop = osg::CopyOp::SHALLOW_COPY
	)

Classic OSG cloning constructor

osgShadow::ViewDependentShadowTechnique::~ViewDependentShadowTechnique ( void  )

protected

Classic protected OSG destructor

Member Function Documentation

virtual void osgShadow::ViewDependentShadowTechnique::cleanSceneGraph ( )

virtual

Clean scene graph from any shadow technique specific nodes, state and drawables.

Reimplemented from osgShadow::ShadowTechnique.

virtual void osgShadow::ViewDependentShadowTechnique::cull ( osgUtil::CullVisitor &  cv )

virtual

Run the cull traversal of the ShadowedScene and set up the rendering for this ShadowTechnique.

Reimplemented from osgShadow::ShadowTechnique.

virtual void osgShadow::ViewDependentShadowTechnique::dirty ( )

virtual

Dirty view data bits and force update of view data resources

Reimplemented from osgShadow::ShadowTechnique.

virtual ViewDependentShadowTechnique::ViewData* osgShadow::ViewDependentShadowTechnique::getViewDependentData ( osgUtil::CullVisitor *  cv )

protectedvirtual

Return view dependent data for the cull visitor

virtual void osgShadow::ViewDependentShadowTechnique::init ( )

virtual

Initialize the ShadowedScene and some data structures.

Reimplemented from osgShadow::ShadowTechnique.

osgShadow::ViewDependentShadowTechnique::META_Object	(	osgShadow	,
		ViewDependentShadowTechnique
	)

Declaration of standard OSG object methods

virtual void osgShadow::ViewDependentShadowTechnique::setViewDependentData ( osgUtil::CullVisitor *  cv, ViewDependentShadowTechnique::ViewData *  data  )

protectedvirtual

Define view dependent data for the cull visitor

virtual void osgShadow::ViewDependentShadowTechnique::traverse ( osg::NodeVisitor &  nv )

virtual

Traverse shadow scene graph.

Reimplemented from osgShadow::ShadowTechnique.

virtual void osgShadow::ViewDependentShadowTechnique::update ( osg::NodeVisitor &  nv )

virtual

Run the update traversal of the ShadowedScene and update any local cached data structures.

Reimplemented from osgShadow::ShadowTechnique.

Member Data Documentation

ViewDataMap osgShadow::ViewDependentShadowTechnique::_viewDataMap

protected

Definition at line 209 of file ViewDependentShadowTechnique.h.

OpenThreads::Mutex osgShadow::ViewDependentShadowTechnique::_viewDataMapMutex

protected

Mutex used to serialize accesses to ViewDataMap

Definition at line 215 of file ViewDependentShadowTechnique.h.

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The documentation for this class was generated from the following file:

• osg_head/include/osgShadow/ViewDependentShadowTechnique.h