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/* -*-c++-*- OpenSceneGraph - Copyright (C) 1998-2006 Robert Osfield
*
* This library is open source and may be redistributed and/or modified under
* the terms of the OpenSceneGraph Public License (OSGPL) version 0.0 or
* (at your option) any later version. The full license is in LICENSE file
* included with this distribution, and on the openscenegraph.org website.
*
* This library is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* OpenSceneGraph Public License for more details.
*/
#ifndef OSGSIM_HEIGHTABOVETERRAIN
#define OSGSIM_HEIGHTABOVETERRAIN 1
#include <osgUtil/IntersectionVisitor>
// include so we can get access to the DatabaseCacheReadCallback
#include <osgSim/LineOfSight>
namespace osgSim {
/** 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.*/
class OSGSIM_EXPORT HeightAboveTerrain
{
public :
HeightAboveTerrain();
/** Clear the internal HAT List so it contains no height above terrain tests.*/
void clear();
/** Add a height above terrain test point in the CoordinateFrame.*/
unsigned int addPoint(const osg::Vec3d& point);
/** Get the number of height above terrain tests.*/
unsigned int getNumPoints() const { return _HATList.size(); }
/** Set the source point of single height above terrain test.*/
void setPoint(unsigned int i, const osg::Vec3d& point) { _HATList[i]._point = point; }
/** Get the source point of single height above terrain test.*/
const osg::Vec3d& getPoint(unsigned int i) const { return _HATList[i]._point; }
/** 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 getHeightAboveTerrain(unsigned int i) const { return _HATList[i]._hat; }
/** Set the lowest height that the should be tested for.
* Defaults to -1000, i.e. 1000m below mean sea level. */
void setLowestHeight(double lowestHeight) { _lowestHeight = lowestHeight; }
/** Get the lowest height that the should be tested for.*/
double getLowestHeight() const { return _lowestHeight; }
/** 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. */
void computeIntersections(osg::Node* scene, osg::Node::NodeMask traversalMask=0xffffffff);
/** Compute the vertical distance between the specified scene graph and a single HAT point. */
static double computeHeightAboveTerrain(osg::Node* scene, const osg::Vec3d& point, osg::Node::NodeMask traversalMask=0xffffffff);
/** Clear the database cache.*/
void clearDatabaseCache() { if (_dcrc.valid()) _dcrc->clearDatabaseCache(); }
/** 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 setDatabaseCacheReadCallback(DatabaseCacheReadCallback* dcrc);
/** Get the ReadCallback that does the reading of external PagedLOD models, and caching of loaded subgraphs.*/
DatabaseCacheReadCallback* getDatabaseCacheReadCallback() { return _dcrc.get(); }
protected :
struct HAT
{
HAT(const osg::Vec3d& point):
_point(point),
_hat(0.0) {}
osg::Vec3d _point;
double _hat;
};
typedef std::vector<HAT> HATList;
double _lowestHeight;
HATList _HATList;
osg::ref_ptr<DatabaseCacheReadCallback> _dcrc;
osgUtil::IntersectionVisitor _intersectionVisitor;
};
}
#endif
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