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| Impostor () |
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| Impostor (const Impostor &es, const osg::CopyOp ©op=osg::CopyOp::SHALLOW_COPY) |
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| META_Node (osgSim, Impostor) |
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virtual void | traverse (osg::NodeVisitor &nv) |
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void | setImpostorThreshold (float distance) |
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float | getImpostorThreshold () const |
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void | setImpostorThresholdToBound (float ratio=1.0f) |
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ImpostorSprite * | findBestImpostorSprite (unsigned int contextID, const osg::Vec3 &currLocalEyePoint) const |
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void | addImpostorSprite (unsigned int contextID, ImpostorSprite *is) |
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ImpostorSpriteList & | getImpostorSpriteList (unsigned int contexID) |
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const ImpostorSpriteList & | getImpostorSpriteList (unsigned int contexID) const |
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virtual osg::BoundingSphere | computeBound () const |
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| LOD () |
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| LOD (const LOD &, const CopyOp ©op=CopyOp::SHALLOW_COPY) |
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| META_Node (osg, LOD) |
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virtual bool | addChild (Node *child) |
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virtual bool | addChild (Node *child, float min, float max) |
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virtual bool | removeChildren (unsigned int pos, unsigned int numChildrenToRemove=1) |
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void | setCenterMode (CenterMode mode) |
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CenterMode | getCenterMode () const |
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void | setCenter (const vec_type ¢er) |
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const vec_type & | getCenter () const |
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void | setRadius (value_type radius) |
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value_type | getRadius () const |
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void | setRangeMode (RangeMode mode) |
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RangeMode | getRangeMode () const |
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void | setRange (unsigned int childNo, float min, float max) |
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float | getMinRange (unsigned int childNo) const |
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float | getMaxRange (unsigned int childNo) const |
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unsigned int | getNumRanges () const |
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void | setRangeList (const RangeList &rangeList) |
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const RangeList & | getRangeList () const |
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| Group () |
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| Group (const Group &, const CopyOp ©op=CopyOp::SHALLOW_COPY) |
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| META_Node (osg, Group) |
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virtual Group * | asGroup () |
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virtual const Group * | asGroup () const |
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virtual bool | insertChild (unsigned int index, Node *child) |
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bool | removeChild (Node *child) |
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bool | removeChild (unsigned int pos, unsigned int numChildrenToRemove=1) |
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virtual bool | replaceChild (Node *origChild, Node *newChild) |
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unsigned int | getNumChildren () const |
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virtual bool | setChild (unsigned int i, Node *node) |
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Node * | getChild (unsigned int i) |
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const Node * | getChild (unsigned int i) const |
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bool | containsNode (const Node *node) const |
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unsigned int | getChildIndex (const Node *node) const |
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virtual void | setThreadSafeRefUnref (bool threadSafe) |
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virtual void | resizeGLObjectBuffers (unsigned int maxSize) |
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virtual void | releaseGLObjects (osg::State *=0) const |
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| Node () |
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| Node (const Node &, const CopyOp ©op=CopyOp::SHALLOW_COPY) |
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virtual Object * | cloneType () const |
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virtual Object * | clone (const CopyOp ©op) const |
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virtual bool | isSameKindAs (const Object *obj) const |
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virtual const char * | libraryName () const |
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virtual const char * | className () const |
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virtual Transform * | asTransform () |
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virtual const Transform * | asTransform () const |
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virtual Switch * | asSwitch () |
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virtual const Switch * | asSwitch () const |
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virtual Geode * | asGeode () |
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virtual const Geode * | asGeode () const |
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virtual osgTerrain::Terrain * | asTerrain () |
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virtual const osgTerrain::Terrain * | asTerrain () const |
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virtual void | accept (NodeVisitor &nv) |
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virtual void | ascend (NodeVisitor &nv) |
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const ParentList & | getParents () const |
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ParentList | getParents () |
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Group * | getParent (unsigned int i) |
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const Group * | getParent (unsigned int i) const |
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unsigned int | getNumParents () const |
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NodePathList | getParentalNodePaths (osg::Node *haltTraversalAtNode=0) const |
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MatrixList | getWorldMatrices (const osg::Node *haltTraversalAtNode=0) const |
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void | setUpdateCallback (NodeCallback *nc) |
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NodeCallback * | getUpdateCallback () |
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const NodeCallback * | getUpdateCallback () const |
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void | addUpdateCallback (NodeCallback *nc) |
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void | removeUpdateCallback (NodeCallback *nc) |
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unsigned int | getNumChildrenRequiringUpdateTraversal () const |
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void | setEventCallback (NodeCallback *nc) |
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NodeCallback * | getEventCallback () |
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const NodeCallback * | getEventCallback () const |
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void | addEventCallback (NodeCallback *nc) |
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void | removeEventCallback (NodeCallback *nc) |
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unsigned int | getNumChildrenRequiringEventTraversal () const |
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void | setCullCallback (NodeCallback *nc) |
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NodeCallback * | getCullCallback () |
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const NodeCallback * | getCullCallback () const |
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void | addCullCallback (NodeCallback *nc) |
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void | removeCullCallback (NodeCallback *nc) |
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void | setCullingActive (bool active) |
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bool | getCullingActive () const |
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unsigned int | getNumChildrenWithCullingDisabled () const |
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bool | isCullingActive () const |
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unsigned int | getNumChildrenWithOccluderNodes () const |
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bool | containsOccluderNodes () const |
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void | setNodeMask (NodeMask nm) |
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NodeMask | getNodeMask () const |
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void | setStateSet (osg::StateSet *stateset) |
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osg::StateSet * | getOrCreateStateSet () |
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osg::StateSet * | getStateSet () |
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const osg::StateSet * | getStateSet () const |
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void | setDescriptions (const DescriptionList &descriptions) |
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DescriptionList & | getDescriptions () |
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const DescriptionList & | getDescriptions () const |
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const std::string & | getDescription (unsigned int i) const |
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std::string & | getDescription (unsigned int i) |
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unsigned int | getNumDescriptions () const |
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void | addDescription (const std::string &desc) |
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void | setInitialBound (const osg::BoundingSphere &bsphere) |
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const BoundingSphere & | getInitialBound () const |
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void | dirtyBound () |
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const BoundingSphere & | getBound () const |
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void | setComputeBoundingSphereCallback (ComputeBoundingSphereCallback *callback) |
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ComputeBoundingSphereCallback * | getComputeBoundingSphereCallback () |
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const
ComputeBoundingSphereCallback * | getComputeBoundingSphereCallback () const |
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| Object () |
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| Object (bool threadSafeRefUnref) |
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| Object (const Object &, const CopyOp ©op=CopyOp::SHALLOW_COPY) |
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virtual void | setName (const std::string &name) |
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void | setName (const char *name) |
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const std::string & | getName () const |
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void | setDataVariance (DataVariance dv) |
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DataVariance | getDataVariance () const |
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virtual void | computeDataVariance () |
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void | setUserDataContainer (osg::UserDataContainer *udc) |
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osg::UserDataContainer * | getUserDataContainer () |
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const osg::UserDataContainer * | getUserDataContainer () const |
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osg::UserDataContainer * | getOrCreateUserDataContainer () |
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virtual void | setUserData (Referenced *obj) |
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virtual Referenced * | getUserData () |
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virtual const Referenced * | getUserData () const |
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template<typename T > |
bool | getUserValue (const std::string &name, T &value) const |
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template<typename T > |
void | setUserValue (const std::string &name, const T &value) |
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| Referenced () |
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| Referenced (bool threadSafeRefUnref) |
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| Referenced (const Referenced &) |
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Referenced & | operator= (const Referenced &) |
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bool | getThreadSafeRefUnref () const |
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OpenThreads::Mutex * | getRefMutex () const |
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int | ref () const |
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int | unref () const |
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int | unref_nodelete () const |
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int | referenceCount () const |
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ObserverSet * | getObserverSet () const |
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ObserverSet * | getOrCreateObserverSet () const |
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void | addObserver (Observer *observer) const |
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void | removeObserver (Observer *observer) const |
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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.