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osgSim::Impostor Class Reference

#include <Impostor>

Inheritance diagram for osgSim::Impostor:
osg::LOD osg::Group osg::Node osg::Object osg::Referenced

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< MinMaxPairRangeList
 
- 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)
 
ImpostorSpritefindBestImpostorSprite (unsigned int contextID, const osg::Vec3 &currLocalEyePoint) const
 
void addImpostorSprite (unsigned int contextID, ImpostorSprite *is)
 
ImpostorSpriteListgetImpostorSpriteList (unsigned int contexID)
 
const ImpostorSpriteListgetImpostorSpriteList (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_typegetCenter () 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 RangeListgetRangeList () const
 
- Public Member Functions inherited from osg::Group
 Group ()
 
 Group (const Group &, const CopyOp &copyop=CopyOp::SHALLOW_COPY)
 
 META_Node (osg, Group)
 
virtual GroupasGroup ()
 
virtual const GroupasGroup () 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)
 
NodegetChild (unsigned int i)
 
const NodegetChild (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 ObjectcloneType () const
 
virtual Objectclone (const CopyOp &copyop) const
 
virtual bool isSameKindAs (const Object *obj) const
 
virtual const char * libraryName () const
 
virtual const char * className () const
 
virtual NodeasNode ()
 
virtual const NodeasNode () const
 
virtual DrawableasDrawable ()
 
virtual const DrawableasDrawable () const
 
virtual GeometryasGeometry ()
 
virtual const GeometryasGeometry () const
 
virtual TransformasTransform ()
 
virtual const TransformasTransform () const
 
virtual SwitchasSwitch ()
 
virtual const SwitchasSwitch () const
 
virtual GeodeasGeode ()
 
virtual const GeodeasGeode () const
 
virtual osgTerrain::TerrainasTerrain ()
 
virtual const osgTerrain::TerrainasTerrain () const
 
virtual void accept (NodeVisitor &nv)
 
virtual void ascend (NodeVisitor &nv)
 
const ParentListgetParents () const
 
ParentList getParents ()
 
GroupgetParent (unsigned int i)
 
const GroupgetParent (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)
 
CallbackgetUpdateCallback ()
 
const CallbackgetUpdateCallback () 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)
 
CallbackgetEventCallback ()
 
const CallbackgetEventCallback () 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)
 
CallbackgetCullCallback ()
 
const CallbackgetCullCallback () 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::StateSetgetOrCreateStateSet ()
 
osg::StateSetgetStateSet ()
 
const osg::StateSetgetStateSet () const
 
void setDescriptions (const DescriptionList &descriptions)
 
DescriptionListgetDescriptions ()
 
const DescriptionListgetDescriptions () 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 BoundingSpheregetInitialBound () const
 
void dirtyBound ()
 
const BoundingSpheregetBound () const
 
void setComputeBoundingSphereCallback (ComputeBoundingSphereCallback *callback)
 
template<class T >
void setComputeBoundingSphereCallback (const ref_ptr< T > &callback)
 
ComputeBoundingSphereCallbackgetComputeBoundingSphereCallback ()
 
const ComputeBoundingSphereCallbackgetComputeBoundingSphereCallback () 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 NodeVisitorasNodeVisitor ()
 
virtual const NodeVisitorasNodeVisitor () const
 
virtual StateSetasStateSet ()
 
virtual const StateSetasStateSet () const
 
virtual StateAttributeasStateAttribute ()
 
virtual const StateAttributeasStateAttribute () const
 
virtual UniformasUniform ()
 
virtual const UniformasUniform () const
 
virtual CameraasCamera ()
 
virtual const CameraasCamera () const
 
virtual CallbackasCallback ()
 
virtual const CallbackasCallback () const
 
virtual CallbackObjectasCallbackObject ()
 
virtual const CallbackObjectasCallbackObject () const
 
virtual UserDataContainerasUserDataContainer ()
 
virtual const UserDataContainerasUserDataContainer () const
 
virtual ValueObjectasValueObject ()
 
virtual const ValueObjectasValueObject () const
 
virtual ImageasImage ()
 
virtual const ImageasImage () 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::UserDataContainergetUserDataContainer ()
 
const osg::UserDataContainergetUserDataContainer () const
 
osg::UserDataContainergetOrCreateUserDataContainer ()
 
virtual void setUserData (Referenced *obj)
 
template<class T >
void setUserData (const ref_ptr< T > &ud)
 
virtual ReferencedgetUserData ()
 
virtual const ReferencedgetUserData () 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 &)
 
Referencedoperator= (const Referenced &)
 
bool getThreadSafeRefUnref () const
 
OpenThreads::MutexgetRefMutex () const
 
int ref () const
 
int unref () const
 
int unref_nodelete () const
 
int referenceCount () const
 
ObserverSetgetObserverSet () const
 
ObserverSetgetOrCreateObserverSet () const
 
void addObserver (Observer *observer) const
 
void removeObserver (Observer *observer) const
 

Protected Member Functions

virtual ~Impostor ()
 
ImpostorSpritecreateImpostorSprite (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::MutexgetGlobalReferencedMutex ()
 
static void setDeleteHandler (DeleteHandler *handler)
 
static DeleteHandlergetDeleteHandler ()
 

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

Constructor & Destructor Documentation

◆ Impostor() [1/2]

osgSim::Impostor::Impostor ( )

◆ Impostor() [2/2]

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

◆ ~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.

◆ getImpostorSpriteList() [2/2]

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

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

◆ getImpostorThreshold()

float osgSim::Impostor::getImpostorThreshold ( ) const
inline

◆ META_Node()

osgSim::Impostor::META_Node ( osgSim  ,
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.

◆ setImpostorThresholdToBound()

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

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

◆ 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

◆ _impostorThreshold

float osgSim::Impostor::_impostorThreshold
protected

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