osgSim::HeightAboveTerrain Class Reference

Helper class for setting up and acquiring height above terrain intersections with terrain. More...

Classes
struct	HAT

Public Member Functions
	HeightAboveTerrain ()
void	clear ()
	Clear the internal HAT List so it contains no height above terrain tests. More...
unsigned int	addPoint (const osg::Vec3d &point)
	Add a height above terrain test point in the CoordinateFrame. More...
unsigned int	getNumPoints () const
	Get the number of height above terrain tests. More...
void	setPoint (unsigned int i, const osg::Vec3d &point)
	Set the source point of single height above terrain test. More...
const osg::Vec3d &	getPoint (unsigned int i) const
	Get the source point of single height above terrain test. More...
double	getHeightAboveTerrain (unsigned int i) const
	Get the intersection height for a single height above terrain test. More...
void	setLowestHeight (double lowestHeight)
	Set the lowest height that the should be tested for. More...
double	getLowestHeight () const
	Get the lowest height that the should be tested for. More...
void	computeIntersections (osg::Node *scene, osg::Node::NodeMask traversalMask=0xffffffff)
	Compute the HAT intersections with the specified scene graph. More...
void	clearDatabaseCache ()
	Clear the database cache. More...
void	setDatabaseCacheReadCallback (DatabaseCacheReadCallback *dcrc)
	Set the ReadCallback that does the reading of external PagedLOD models, and caching of loaded subgraphs. More...
DatabaseCacheReadCallback *	getDatabaseCacheReadCallback ()
	Get the ReadCallback that does the reading of external PagedLOD models, and caching of loaded subgraphs. More...

Static Public Member Functions
static double	computeHeightAboveTerrain (osg::Node *scene, const osg::Vec3d &point, osg::Node::NodeMask traversalMask=0xffffffff)
	Compute the vertical distance between the specified scene graph and a single HAT point. More...

Protected Types
typedef std::vector< HAT >	HATList

Protected Attributes
double	_lowestHeight
HATList	_HATList
osg::ref_ptr< DatabaseCacheReadCallback >	_dcrc
osgUtil::IntersectionVisitor	_intersectionVisitor

Detailed Description

Helper class for setting up and acquiring height above terrain intersections with terrain.

By default assigns a osgSim::DatabaseCacheReadCallback that enables automatic loading of external PagedLOD tiles to ensure that the highest level of detail is used in intersections. This automatic loading of tiles is done by the intersection traversal that is done within the computeIntersections(..) method, so can result in long intersection times when external tiles have to be loaded. The external loading of tiles can be disabled by removing the read callback, this is done by calling the setDatabaseCacheReadCallback(DatabaseCacheReadCallback*) method with a value of 0.

Member Typedef Documentation

typedef std::vector<HAT> osgSim::HeightAboveTerrain::HATList

protected

Constructor & Destructor Documentation

osgSim::HeightAboveTerrain::HeightAboveTerrain

(

)

Member Function Documentation

unsigned int osgSim::HeightAboveTerrain::addPoint

(

const osg::Vec3d &

point

)

Add a height above terrain test point in the CoordinateFrame.

void osgSim::HeightAboveTerrain::clear

(

)

Clear the internal HAT List so it contains no height above terrain tests.

void osgSim::HeightAboveTerrain::clearDatabaseCache ( )

inline

Clear the database cache.

static double osgSim::HeightAboveTerrain::computeHeightAboveTerrain ( osg::Node *  scene, const osg::Vec3d &  point, osg::Node::NodeMask  traversalMask = 0xffffffff  )

static

Compute the vertical distance between the specified scene graph and a single HAT point.

void osgSim::HeightAboveTerrain::computeIntersections	(	osg::Node *	scene,
		osg::Node::NodeMask	traversalMask = 0xffffffff
	)

Compute the HAT intersections with the specified scene graph.

The results are all stored in the form of a single height above terrain value per HAT test. Note, if the topmost node is a CoordinateSystemNode then the input points are assumed to be geocentric, with the up vector defined by the EllipsoidModel attached to the CoordinateSystemNode. If the topmost node is not a CoordinateSystemNode then a local coordinates frame is assumed, with a local up vector.

DatabaseCacheReadCallback* osgSim::HeightAboveTerrain::getDatabaseCacheReadCallback ( )

inline

Get the ReadCallback that does the reading of external PagedLOD models, and caching of loaded subgraphs.

double osgSim::HeightAboveTerrain::getHeightAboveTerrain ( unsigned int  i ) const

inline

Get the intersection height for a single height above terrain test.

Note, you must call computeIntersections(..) before you can query the HeightAboveTerrain. If no intersections are found then height returned will be the height above mean sea level.

double osgSim::HeightAboveTerrain::getLowestHeight ( ) const

inline

Get the lowest height that the should be tested for.

unsigned int osgSim::HeightAboveTerrain::getNumPoints ( ) const

inline

Get the number of height above terrain tests.

const osg::Vec3d& osgSim::HeightAboveTerrain::getPoint ( unsigned int  i ) const

inline

Get the source point of single height above terrain test.

void osgSim::HeightAboveTerrain::setDatabaseCacheReadCallback

(

DatabaseCacheReadCallback *

dcrc

)

Set the ReadCallback that does the reading of external PagedLOD models, and caching of loaded subgraphs.

Note, if you have multiple LineOfSight or HeightAboveTerrain objects in use at one time then you should share a single DatabaseCacheReadCallback between all of them.

void osgSim::HeightAboveTerrain::setLowestHeight ( double  lowestHeight )

inline

Set the lowest height that the should be tested for.

Defaults to -1000, i.e. 1000m below mean sea level.

void osgSim::HeightAboveTerrain::setPoint ( unsigned int  i, const osg::Vec3d &  point  )

inline

Set the source point of single height above terrain test.

Member Data Documentation

osg::ref_ptr<DatabaseCacheReadCallback> osgSim::HeightAboveTerrain::_dcrc

protected

HATList osgSim::HeightAboveTerrain::_HATList

protected

osgUtil::IntersectionVisitor osgSim::HeightAboveTerrain::_intersectionVisitor

protected

double osgSim::HeightAboveTerrain::_lowestHeight

protected

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

• osgSim/HeightAboveTerrain