#include <Impostor>

Inheritance diagram for osgSim::Impostor:

Public Types
typedef std::vector< osg::ref_ptr< ImpostorSprite > >	ImpostorSpriteList
Public Types inherited from osg::LOD
enum	CenterMode { USE_BOUNDING_SPHERE_CENTER , USER_DEFINED_CENTER , UNION_OF_BOUNDING_SPHERE_AND_USER_DEFINED }
enum	RangeMode { DISTANCE_FROM_EYE_POINT , PIXEL_SIZE_ON_SCREEN }
typedef osg::BoundingSphere::vec_type	vec_type
typedef osg::BoundingSphere::value_type	value_type
typedef std::pair< float, float >	MinMaxPair
typedef std::vector< MinMaxPair >	RangeList
Public Types inherited from osg::Node
typedef std::vector< Group * >	ParentList
typedef unsigned int	NodeMask
typedef std::vector< std::string >	DescriptionList
Public Types inherited from osg::Object
enum	DataVariance { DYNAMIC , STATIC , UNSPECIFIED }

Public Member Functions
	Impostor ()
	Impostor (const Impostor &es, const osg::CopyOp &copyop=osg::CopyOp::SHALLOW_COPY)
	META_Node (osgSim, Impostor)
virtual void	traverse (osg::NodeVisitor &nv)
void	setImpostorThreshold (float distance)
float	getImpostorThreshold () const
void	setImpostorThresholdToBound (float ratio=1.0f)
ImpostorSprite *	findBestImpostorSprite (unsigned int contextID, const osg::Vec3 &currLocalEyePoint) const
void	addImpostorSprite (unsigned int contextID, ImpostorSprite *is)
ImpostorSpriteList &	getImpostorSpriteList (unsigned int contexID)
const ImpostorSpriteList &	getImpostorSpriteList (unsigned int contexID) const
virtual osg::BoundingSphere	computeBound () const
Public Member Functions inherited from osg::LOD
	LOD ()
	LOD (const LOD &, const CopyOp &copyop=CopyOp::SHALLOW_COPY)
	META_Node (osg, LOD)
virtual bool	addChild (Node *child)
virtual bool	addChild (Node *child, float rmin, float rmax)
template<class T>
bool	addChild (const ref_ptr< T > &child, float rmin, float rmax)
virtual bool	removeChildren (unsigned int pos, unsigned int numChildrenToRemove=1)
void	setCenterMode (CenterMode mode)
CenterMode	getCenterMode () const
void	setCenter (const vec_type &center)
const vec_type &	getCenter () const
void	setRadius (value_type radius)
value_type	getRadius () const
void	setRangeMode (RangeMode mode)
RangeMode	getRangeMode () const
void	setRange (unsigned int childNo, float min, float max)
float	getMinRange (unsigned int childNo) const
float	getMaxRange (unsigned int childNo) const
unsigned int	getNumRanges () const
void	setRangeList (const RangeList &rangeList)
const RangeList &	getRangeList () const
template<class T>
bool	addChild (const ref_ptr< T > &child)
Public Member Functions inherited from osg::Group
	Group ()
	Group (const Group &, const CopyOp &copyop=CopyOp::SHALLOW_COPY)
	META_Node (osg, Group)
virtual Group *	asGroup ()
virtual const Group *	asGroup () const
template<class T>
bool	addChild (const ref_ptr< T > &child)
virtual bool	insertChild (unsigned int index, Node *child)
template<class T>
bool	insertChild (unsigned int index, const ref_ptr< T > &child)
virtual bool	removeChild (Node *child)
template<class T>
bool	removeChild (const ref_ptr< T > &child)
bool	removeChild (unsigned int pos, unsigned int numChildrenToRemove=1)
virtual bool	replaceChild (Node origChild, Node newChild)
template<class T, class R>
bool	replaceChild (const ref_ptr< T > &origChild, const ref_ptr< R > &newChild)
virtual unsigned int	getNumChildren () const
virtual bool	setChild (unsigned int i, Node *node)
Node *	getChild (unsigned int i)
const Node *	getChild (unsigned int i) const
bool	containsNode (const Node *node) const
template<class T>
bool	containsNode (const ref_ptr< T > &node) const
unsigned int	getChildIndex (const Node *node) const
virtual void	setThreadSafeRefUnref (bool threadSafe)
virtual void	resizeGLObjectBuffers (unsigned int maxSize)
virtual void	releaseGLObjects (osg::State *=0) const
Public Member Functions inherited from osg::Node
	Node ()
	Node (const Node &, const CopyOp &copyop=CopyOp::SHALLOW_COPY)
virtual Object *	cloneType () const
virtual Object *	clone (const CopyOp &copyop) const
virtual bool	isSameKindAs (const Object *obj) const
virtual const char *	libraryName () const
virtual const char *	className () const
virtual Node *	asNode ()
virtual const Node *	asNode () const
virtual Drawable *	asDrawable ()
virtual const Drawable *	asDrawable () const
virtual Geometry *	asGeometry ()
virtual const Geometry *	asGeometry () const
virtual Transform *	asTransform ()
virtual const Transform *	asTransform () const
virtual Switch *	asSwitch ()
virtual const Switch *	asSwitch () const
virtual Geode *	asGeode ()
virtual const Geode *	asGeode () const
virtual osgTerrain::Terrain *	asTerrain ()
virtual const osgTerrain::Terrain *	asTerrain () const
virtual void	accept (NodeVisitor &nv)
virtual void	ascend (NodeVisitor &nv)
const ParentList &	getParents () const
ParentList	getParents ()
Group *	getParent (unsigned int i)
const Group *	getParent (unsigned int i) const
unsigned int	getNumParents () const
NodePathList	getParentalNodePaths (osg::Node *haltTraversalAtNode=0) const
MatrixList	getWorldMatrices (const osg::Node *haltTraversalAtNode=0) const
void	setUpdateCallback (Callback *nc)
template<class T>
void	setUpdateCallback (const ref_ptr< T > &nc)
Callback *	getUpdateCallback ()
const Callback *	getUpdateCallback () const
void	addUpdateCallback (Callback *nc)
template<class T>
void	addUpdateCallback (const ref_ptr< T > &nc)
void	removeUpdateCallback (Callback *nc)
template<class T>
void	removeUpdateCallback (const ref_ptr< T > &nc)
unsigned int	getNumChildrenRequiringUpdateTraversal () const
void	setEventCallback (Callback *nc)
template<class T>
void	setEventCallback (const ref_ptr< T > &nc)
Callback *	getEventCallback ()
const Callback *	getEventCallback () const
void	addEventCallback (Callback *nc)
template<class T>
void	addEventCallback (const ref_ptr< T > &nc)
void	removeEventCallback (Callback *nc)
template<class T>
void	removeEventCallback (const ref_ptr< T > &nc)
unsigned int	getNumChildrenRequiringEventTraversal () const
void	setCullCallback (Callback *nc)
template<class T>
void	setCullCallback (const ref_ptr< T > &nc)
Callback *	getCullCallback ()
const Callback *	getCullCallback () const
void	addCullCallback (Callback *nc)
template<class T>
void	addCullCallback (const ref_ptr< T > &nc)
void	removeCullCallback (Callback *nc)
template<class T>
void	removeCullCallback (const ref_ptr< T > &nc)
void	setCullingActive (bool active)
bool	getCullingActive () const
unsigned int	getNumChildrenWithCullingDisabled () const
bool	isCullingActive () const
unsigned int	getNumChildrenWithOccluderNodes () const
bool	containsOccluderNodes () const
void	setNodeMask (NodeMask nm)
NodeMask	getNodeMask () const
void	setStateSet (osg::StateSet *stateset)
template<class T>
void	setStateSet (const osg::ref_ptr< T > &stateset)
osg::StateSet *	getOrCreateStateSet ()
osg::StateSet *	getStateSet ()
const osg::StateSet *	getStateSet () const
void	setDescriptions (const DescriptionList &descriptions)
DescriptionList &	getDescriptions ()
const DescriptionList &	getDescriptions () const
const std::string &	getDescription (unsigned int i) const
std::string &	getDescription (unsigned int i)
unsigned int	getNumDescriptions () const
void	addDescription (const std::string &desc)
void	setInitialBound (const osg::BoundingSphere &bsphere)
const BoundingSphere &	getInitialBound () const
void	dirtyBound ()
const BoundingSphere &	getBound () const
void	setComputeBoundingSphereCallback (ComputeBoundingSphereCallback *callback)
template<class T>
void	setComputeBoundingSphereCallback (const ref_ptr< T > &callback)
ComputeBoundingSphereCallback *	getComputeBoundingSphereCallback ()
const ComputeBoundingSphereCallback *	getComputeBoundingSphereCallback () const
Public Member Functions inherited from osg::Object
	Object ()
	Object (bool threadSafeRefUnref)
	Object (const Object &, const CopyOp &copyop=CopyOp::SHALLOW_COPY)
std::string	getCompoundClassName () const
virtual NodeVisitor *	asNodeVisitor ()
virtual const NodeVisitor *	asNodeVisitor () const
virtual StateSet *	asStateSet ()
virtual const StateSet *	asStateSet () const
virtual StateAttribute *	asStateAttribute ()
virtual const StateAttribute *	asStateAttribute () const
virtual Uniform *	asUniform ()
virtual const Uniform *	asUniform () const
virtual Camera *	asCamera ()
virtual const Camera *	asCamera () const
virtual Callback *	asCallback ()
virtual const Callback *	asCallback () const
virtual CallbackObject *	asCallbackObject ()
virtual const CallbackObject *	asCallbackObject () const
virtual UserDataContainer *	asUserDataContainer ()
virtual const UserDataContainer *	asUserDataContainer () const
virtual ValueObject *	asValueObject ()
virtual const ValueObject *	asValueObject () const
virtual Image *	asImage ()
virtual const Image *	asImage () const
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)
template<class T>
void	setUserDataContainer (const ref_ptr< T > &udc)
osg::UserDataContainer *	getUserDataContainer ()
const osg::UserDataContainer *	getUserDataContainer () const
osg::UserDataContainer *	getOrCreateUserDataContainer ()
virtual void	setUserData (Referenced *obj)
template<class T>
void	setUserData (const ref_ptr< T > &ud)
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)
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 Member Functions
virtual	~Impostor ()
ImpostorSprite *	createImpostorSprite (osgUtil::CullVisitor *cv)
Protected Member Functions inherited from osg::LOD
virtual	~LOD ()
Protected Member Functions inherited from osg::Group
virtual	~Group ()
virtual void	childRemoved (unsigned int, unsigned int)
virtual void	childInserted (unsigned int)
Protected Member Functions inherited from osg::Node
virtual	~Node ()
void	addParent (osg::Group *parent)
void	removeParent (osg::Group *parent)
void	setNumChildrenRequiringUpdateTraversal (unsigned int num)
void	setNumChildrenRequiringEventTraversal (unsigned int num)
void	setNumChildrenWithCullingDisabled (unsigned int num)
void	setNumChildrenWithOccluderNodes (unsigned int num)
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
osg::buffered_object< ImpostorSpriteList >	_impostorSpriteListBuffer
float	_impostorThreshold
Protected Attributes inherited from osg::LOD
CenterMode	_centerMode
vec_type	_userDefinedCenter
value_type	_radius
RangeMode	_rangeMode
RangeList	_rangeList
Protected Attributes inherited from osg::Group
NodeList	_children
Protected Attributes inherited from osg::Node
BoundingSphere	_initialBound
ref_ptr< ComputeBoundingSphereCallback >	_computeBoundCallback
BoundingSphere	_boundingSphere
bool	_boundingSphereComputed
ParentList	_parents
ref_ptr< Callback >	_updateCallback
unsigned int	_numChildrenRequiringUpdateTraversal
ref_ptr< Callback >	_eventCallback
unsigned int	_numChildrenRequiringEventTraversal
ref_ptr< Callback >	_cullCallback
bool	_cullingActive
unsigned int	_numChildrenWithCullingDisabled
unsigned int	_numChildrenWithOccluderNodes
NodeMask	_nodeMask
ref_ptr< StateSet >	_stateset
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
Static Public Member Functions inherited from osg::Referenced
static OpenThreads::Mutex *	getGlobalReferencedMutex ()
static void	setDeleteHandler (DeleteHandler *handler)
static DeleteHandler *	getDeleteHandler ()

Detailed Description

Impostor - is a form of Level Of Detail group node which allows both switching between children depending on distance from eye point and image caching.

The principle behind Imposters is that they cache an image of real geometry and then the image is drawn in subsequent frames instead of the real geometry. It's a bit like a Billboard but is updated at runtime and w.r.t view point. By drawing just the texture mapped quad you can cut down scene complexity and improve performance.

For more details have a look at:

http://grail.cs.washington.edu/projects/hic/

The OSG doesn't implement exactly the same technique as above, but its should be a good starting place. The OSG's impostors are much less intrusive since you don't need to restructure your whole scene to use them.

All you need to do to use Impostors is to set up the visible range values for each LOD child of the Impostor, as per osg::LOD, and set an Impostor threshold to tell the renderer at what distance the Impostor's image caching should cut in. The osg::CullVisitor automatically handles all the setting of pre-rendering stages to calculate the required ImpostorSprites (which encapsulates the image cache and quad), and updates them as the view point changes. If you use osg::SceneView/CullVisitor all the complexity of supporting Impostor will be nicely hidden away.

TODO: Various improvements are planned for the Impostor- 1) Estimation of how many frames an ImpostorSprite will be reused, if it won't be used more often than a minimum threshold then do not create ImpostorSprite - use the real geometry. 2) Sharing of texture memory between ImpostorSprites. 3) Simple 3D geometry for ImpostorSprite's rather than Billboarding. 4) Shrinking of the ImpostorSprite size to more closely fit the underlying geometry.

Member Typedef Documentation

◆ ImpostorSpriteList

typedef std::vector< osg::ref_ptr<ImpostorSprite> > osgSim::Impostor::ImpostorSpriteList

Constructor & Destructor Documentation

◆ Impostor() [1/2]

osgSim::Impostor::Impostor ( )

Referenced by Impostor(), and META_Node().

◆ Impostor() [2/2]

osgSim::Impostor::Impostor	(	const Impostor &	es,
		const osg::CopyOp &	copyop = osg::CopyOp::SHALLOW_COPY )

inline

References _impostorThreshold, Impostor(), osg::LOD::LOD(), and osg::CopyOp::SHALLOW_COPY.

◆ ~Impostor()

virtual osgSim::Impostor::~Impostor ( )

inlineprotectedvirtual

Member Function Documentation

◆ addImpostorSprite()

void osgSim::Impostor::addImpostorSprite	(	unsigned int	contextID,
		ImpostorSprite *	is )

Add an ImpostorSprite to the Impostor.

◆ computeBound()

virtual osg::BoundingSphere osgSim::Impostor::computeBound ( ) const

virtual

Compute the bounding sphere around Node's geometry or children. This method is automatically called by getBound() when the bounding sphere has been marked dirty via dirtyBound().

Reimplemented from osg::LOD.

◆ createImpostorSprite()

ImpostorSprite * osgSim::Impostor::createImpostorSprite ( osgUtil::CullVisitor * cv )

protected

◆ findBestImpostorSprite()

ImpostorSprite * osgSim::Impostor::findBestImpostorSprite	(	unsigned int	contextID,
		const osg::Vec3 &	currLocalEyePoint ) const

Find the ImposterSprite which fits the current eye point best.

◆ getImpostorSpriteList() [1/2]

ImpostorSpriteList & osgSim::Impostor::getImpostorSpriteList ( unsigned int contexID )

inline

Get the list of ImpostorSprites attached to this Impostor.

References _impostorSpriteListBuffer.

◆ getImpostorSpriteList() [2/2]

const ImpostorSpriteList & osgSim::Impostor::getImpostorSpriteList ( unsigned int contexID ) const

inline

Get a const list of ImpostorSprites attached to this const Impostor.

References _impostorSpriteListBuffer.

◆ getImpostorThreshold()

float osgSim::Impostor::getImpostorThreshold ( ) const

inline

References _impostorThreshold.

◆ META_Node()

osgSim::Impostor::META_Node	(	osgSim	,
		Impostor	)

References Impostor().

◆ setImpostorThreshold()

void osgSim::Impostor::setImpostorThreshold ( float distance )

inline

Set the Impostor threshold distance. For eye points further than this threshold the Imposter is used if appropriate, otherwise the LOD children as chosen as per a standard LOD node.

References _impostorThreshold.

◆ setImpostorThresholdToBound()

void osgSim::Impostor::setImpostorThresholdToBound ( float ratio = 1.0f )

inline

Set the Impostor threshold distance relative to the node's bounding sphere's radius.

References _impostorThreshold, and osg::Node::getBound().

◆ traverse()

virtual void osgSim::Impostor::traverse ( osg::NodeVisitor & )

virtual

Traverse downwards : calls children's accept method with NodeVisitor.

Reimplemented from osg::LOD.

Member Data Documentation

◆ _impostorSpriteListBuffer

osg::buffered_object<ImpostorSpriteList> osgSim::Impostor::_impostorSpriteListBuffer

mutableprotected

Referenced by getImpostorSpriteList(), and getImpostorSpriteList().

◆ _impostorThreshold

float osgSim::Impostor::_impostorThreshold

protected

Referenced by getImpostorThreshold(), Impostor(), setImpostorThreshold(), and setImpostorThresholdToBound().

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

Impostor

Public Types

Public Member Functions

Protected Member Functions

Protected Attributes

Additional Inherited Members

Detailed Description

Member Typedef Documentation

◆ ImpostorSpriteList

Constructor & Destructor Documentation

◆ Impostor() [1/2]

◆ Impostor() [2/2]

◆ ~Impostor()

Member Function Documentation

◆ addImpostorSprite()

◆ computeBound()

◆ createImpostorSprite()

◆ findBestImpostorSprite()

◆ getImpostorSpriteList() [1/2]

◆ getImpostorSpriteList() [2/2]

◆ getImpostorThreshold()

◆ META_Node()

◆ setImpostorThreshold()

◆ setImpostorThresholdToBound()

◆ traverse()

Member Data Documentation

◆ _impostorSpriteListBuffer

◆ _impostorThreshold