osg::LOD Class Reference

LOD - Level Of Detail group node which allows switching between children depending on distance from eye point. More...

Inheritance diagram for osg::LOD:

[legend]List of all members.

Public Types
typedef std::pair< float, float >	MinMaxPair
typedef std::vector< MinMaxPair >	RangeList
enum	CenterMode { USE_BOUNDING_SPHERE_CENTER, USER_DEFINED_CENTER }
	Modes which control how the center of object should be determined when computing which child is active. More...
enum	RangeMode { DISTANCE_FROM_EYE_POINT, PIXEL_SIZE_ON_SCREEN }
	Modes that control how the range values should be intepreted when computing which child is active. More...
Public Member Functions
	LOD ()
	LOD (const LOD &, const CopyOp &copyop=CopyOp::SHALLOW_COPY)
	Copy constructor using CopyOp to manage deep vs shallow copy.
	META_Node (osg, LOD)
virtual void	traverse (NodeVisitor &nv)
	Traverse downwards : calls children's accept method with NodeVisitor.
virtual bool	addChild (Node *child)
	Add Node to Group.
virtual bool	addChild (Node *child, float min, float max)
virtual bool	removeChild (Node *child)
	Remove Node from Group.
void	setCenterMode (CenterMode mode)
	Set how the center of object should be determined when computing which child is active.
CenterMode	getCenterMode () const
	Get how the center of object should be determined when computing which child is active.
void	setCenter (const Vec3 &center)
	Sets the object-space point which defines the center of the osg::LOD.
const Vec3 &	getCenter () const
	return the LOD center point.
void	setRadius (float radius)
	Set the object-space reference radius of the volume enclosed by the LOD.
float	getRadius () const
	Get the object-space radius of the volume enclosed by the LOD.
void	setRangeMode (RangeMode mode)
	Set how the range values should be intepreted when computing which child is active.
RangeMode	getRangeMode () const
	Get how the range values should be intepreted when computing which child is active.
void	setRange (unsigned int childNo, float min, float max)
	Sets the min and max visible ranges of range of specifiec child.
float	getMinRange (unsigned int childNo) const
	returns the min visible range for specified child.
float	getMaxRange (unsigned int childNo) const
	returns the max visible range for specified child.
unsigned int	getNumRanges () const
	returns the number of ranges currently set.
void	setRangeList (const RangeList &rangeList)
	set the list of MinMax ranges for each child.
const RangeList &	getRangeList () const
	return the list of MinMax ranges for each child.
virtual BoundingSphere	computeBound () const
	Compute the bounding sphere around Node's geometry or children.
Protected Member Functions
virtual	~LOD ()
virtual void	childRemoved (unsigned int pos, unsigned int numChildrenToRemove)
virtual void	childInserted (unsigned int pos)
virtual void	rangeRemoved (unsigned int, unsigned int)
virtual void	rangeInserted (unsigned int)
Protected Attributes
CenterMode	_centerMode
Vec3	_userDefinedCenter
float	_radius
RangeMode	_rangeMode
RangeList	_rangeList

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Detailed Description

LOD - Level Of Detail group node which allows switching between children depending on distance from eye point.

Typical uses are for load balancing - objects further away from the eye point are rendered at a lower level of detail, and at times of high stress on the graphics pipeline lower levels of detail can also be chosen. The children are ordered from most detailed (for close up views) to the least (see from a distance), and a set of ranges are used to decide which LOD is used at different view distances, the criteria used is child 'i' is used when range[i]<dist<range[i+1] is true. This requires there to be n+1 range values where the number of children is n, since no maximum distance of infinity is assumed. If the number of range values (m) is insufficient then the children m through to n will be ignored, only 0..m-1 will be used during rendering.

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Member Typedef Documentation

typedef std::pair<float,float> osg::LOD::MinMaxPair

typedef std::vector<MinMaxPair> osg::LOD::RangeList

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Member Enumeration Documentation

enum osg::LOD::CenterMode

Modes which control how the center of object should be determined when computing which child is active. Enumeration values: USE_BOUNDING_SPHERE_CENTER  USER_DEFINED_CENTER

enum osg::LOD::RangeMode

Modes that control how the range values should be intepreted when computing which child is active. Enumeration values: DISTANCE_FROM_EYE_POINT  PIXEL_SIZE_ON_SCREEN

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Constructor & Destructor Documentation

osg::LOD::LOD (   )

osg::LOD::LOD (  const LOD &  , const CopyOp &  copyop = CopyOp::SHALLOW_COPY )

Copy constructor using CopyOp to manage deep vs shallow copy.

virtual osg::LOD::~LOD (   )  [inline, protected, virtual]

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Member Function Documentation

virtual bool osg::LOD::addChild (  Node *  child, float  min, float  max )  [virtual]

Reimplemented in osg::PagedLOD.

virtual bool osg::LOD::addChild (  Node *  child  )  [virtual]

Add Node to Group. If node is not NULL and is not contained in Group then increment its reference count, add it to the child list and dirty the bounding sphere to force it to recompute on next getBound() and return true for success. Otherwise return false. Scene nodes can't be added as child nodes. Reimplemented from osg::Group. Reimplemented in osg::PagedLOD.

virtual void osg::LOD::childInserted (  unsigned int  pos  )  [protected, virtual]

Reimplemented from osg::Group. Reimplemented in osg::PagedLOD.

virtual void osg::LOD::childRemoved (  unsigned int  pos, unsigned int  numChildrenToRemove )  [protected, virtual]

Reimplemented from osg::Group. Reimplemented in osg::PagedLOD.

virtual BoundingSphere osg::LOD::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::Group. Reimplemented in osgSim::Impostor.

const Vec3& osg::LOD::getCenter (   )  const [inline]

return the LOD center point.

CenterMode osg::LOD::getCenterMode (   )  const [inline]

Get how the center of object should be determined when computing which child is active.

float osg::LOD::getMaxRange (  unsigned int  childNo  )  const [inline]

returns the max visible range for specified child.

float osg::LOD::getMinRange (  unsigned int  childNo  )  const [inline]

returns the min visible range for specified child.

unsigned int osg::LOD::getNumRanges (   )  const [inline]

returns the number of ranges currently set. An LOD which has been fully set up will have getNumChildren()==getNumRanges().

float osg::LOD::getRadius (   )  const [inline]

Get the object-space radius of the volume enclosed by the LOD.

const RangeList& osg::LOD::getRangeList (   )  const [inline]

return the list of MinMax ranges for each child.

RangeMode osg::LOD::getRangeMode (   )  const [inline]

Get how the range values should be intepreted when computing which child is active.

osg::LOD::META_Node (  osg  , LOD  )

virtual void osg::LOD::rangeInserted (  unsigned  int  )  [inline, protected, virtual]

Reimplemented in osg::PagedLOD.

virtual void osg::LOD::rangeRemoved (  unsigned  int, unsigned  int )  [inline, protected, virtual]

Reimplemented in osg::PagedLOD.

virtual bool osg::LOD::removeChild (  Node *  child  )  [virtual]

Remove Node from Group. If Node is contained in Group then remove it from the child list, decrement its reference count, and dirty the bounding sphere to force it to recompute on next getBound() and return true for success. If Node is not found then return false and do not change the reference count of the Node. Reimplemented from osg::Group. Reimplemented in osg::PagedLOD.

void osg::LOD::setCenter (  const Vec3 &  center  )  [inline]

Sets the object-space point which defines the center of the osg::LOD. center is affected by any transforms in the hierarchy above the osg::LOD.

void osg::LOD::setCenterMode (  CenterMode  mode  )  [inline]

Set how the center of object should be determined when computing which child is active.

void osg::LOD::setRadius (  float  radius  )  [inline]

Set the object-space reference radius of the volume enclosed by the LOD. Used to detmine the bounding sphere of the LOD in the absense of any children.

void osg::LOD::setRange (  unsigned int  childNo, float  min, float  max )

Sets the min and max visible ranges of range of specifiec child. Values are floating point distance specified in local objects coordinates.

void osg::LOD::setRangeList (  const RangeList &  rangeList  )  [inline]

set the list of MinMax ranges for each child.

void osg::LOD::setRangeMode (  RangeMode  mode  )  [inline]

Set how the range values should be intepreted when computing which child is active.

virtual void osg::LOD::traverse (  NodeVisitor &  nv  )  [virtual]

Traverse downwards : calls children's accept method with NodeVisitor. Reimplemented from osg::Group. Reimplemented in osg::PagedLOD, and osgSim::Impostor.

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Member Data Documentation

CenterMode osg::LOD::_centerMode [protected]

float osg::LOD::_radius [protected]

RangeList osg::LOD::_rangeList [protected]

RangeMode osg::LOD::_rangeMode [protected]

Vec3 osg::LOD::_userDefinedCenter [protected]

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

• LOD

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