Robert
I have added a method called set (did not know what to call it) that
allows you to set the start and end points for the LinSegmentIntersector
using the CooridnateFrame and the x, y values like one of the
constructors does. It just makes it easier to reset the start and end
points without having to know which values to use depending on the
CoordinateFrame.
Judd
Robert Osfield wrote:
Hi Judd,
I have done some work on osgUtil::IntersectionVisitor to add proper
support for Billboards. Could you try out the attached
IntersectionVisitor header/source files and let me know how you get
on. This builds against OSG-2.6/OSG-SVN, but might also compile
against 2.4.
In my own testing 'osgpick lz.osg' now works fine, whereas before this
fix it failed to pick the billboarded trees.
Robert.
/* -*-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.
*/
#include <osgUtil/LineSegmentIntersector>
#include <osg/Geometry>
#include <osg/Notify>
#include <osg/io_utils>
#include <osg/TriangleFunctor>
using namespace osgUtil;
namespace LineSegmentIntersectorUtils
{
struct TriangleIntersection
{
TriangleIntersection(unsigned int index, const osg::Vec3& normal, float
r1, const osg::Vec3* v1, float r2, const osg::Vec3* v2, float r3, const
osg::Vec3* v3):
_index(index),
_normal(normal),
_r1(r1),
_v1(v1),
_r2(r2),
_v2(v2),
_r3(r3),
_v3(v3) {}
unsigned int _index;
const osg::Vec3 _normal;
float _r1;
const osg::Vec3* _v1;
float _r2;
const osg::Vec3* _v2;
float _r3;
const osg::Vec3* _v3;
};
typedef std::multimap<float,TriangleIntersection> TriangleIntersections;
struct TriangleIntersector
{
osg::Vec3 _s;
osg::Vec3 _d;
float _length;
int _index;
float _ratio;
bool _hit;
TriangleIntersections _intersections;
TriangleIntersector()
{
_length = 0.0f;
_index = 0;
_ratio = 0.0f;
_hit = false;
}
void set(const osg::Vec3d& start, osg::Vec3d& end, float ratio=FLT_MAX)
{
_hit=false;
_index = 0;
_ratio = ratio;
_s = start;
_d = end - start;
_length = _d.length();
_d /= _length;
}
inline void operator () (const osg::Vec3& v1,const osg::Vec3& v2,const
osg::Vec3& v3, bool treatVertexDataAsTemporary)
{
++_index;
if (v1==v2 || v2==v3 || v1==v3) return;
osg::Vec3 v12 = v2-v1;
osg::Vec3 n12 = v12^_d;
float ds12 = (_s-v1)*n12;
float d312 = (v3-v1)*n12;
if (d312>=0.0f)
{
if (ds12<0.0f) return;
if (ds12>d312) return;
}
else // d312 < 0
{
if (ds12>0.0f) return;
if (ds12<d312) return;
}
osg::Vec3 v23 = v3-v2;
osg::Vec3 n23 = v23^_d;
float ds23 = (_s-v2)*n23;
float d123 = (v1-v2)*n23;
if (d123>=0.0f)
{
if (ds23<0.0f) return;
if (ds23>d123) return;
}
else // d123 < 0
{
if (ds23>0.0f) return;
if (ds23<d123) return;
}
osg::Vec3 v31 = v1-v3;
osg::Vec3 n31 = v31^_d;
float ds31 = (_s-v3)*n31;
float d231 = (v2-v3)*n31;
if (d231>=0.0f)
{
if (ds31<0.0f) return;
if (ds31>d231) return;
}
else // d231 < 0
{
if (ds31>0.0f) return;
if (ds31<d231) return;
}
float r3;
if (ds12==0.0f) r3=0.0f;
else if (d312!=0.0f) r3 = ds12/d312;
else return; // the triangle and the line must be parallel
intersection.
float r1;
if (ds23==0.0f) r1=0.0f;
else if (d123!=0.0f) r1 = ds23/d123;
else return; // the triangle and the line must be parallel
intersection.
float r2;
if (ds31==0.0f) r2=0.0f;
else if (d231!=0.0f) r2 = ds31/d231;
else return; // the triangle and the line must be parallel
intersection.
float total_r = (r1+r2+r3);
if (total_r!=1.0f)
{
if (total_r==0.0f) return; // the triangle and the line must be
parallel intersection.
float inv_total_r = 1.0f/total_r;
r1 *= inv_total_r;
r2 *= inv_total_r;
r3 *= inv_total_r;
}
osg::Vec3 in = v1*r1+v2*r2+v3*r3;
if (!in.valid())
{
osg::notify(osg::WARN)<<"Warning:: Picked up error in
TriangleIntersect"<<std::endl;
osg::notify(osg::WARN)<<"
("<<v1<<",\t"<<v2<<",\t"<<v3<<")"<<std::endl;
osg::notify(osg::WARN)<<"
("<<r1<<",\t"<<r2<<",\t"<<r3<<")"<<std::endl;
return;
}
float d = (in-_s)*_d;
if (d<0.0f) return;
if (d>_length) return;
osg::Vec3 normal = v12^v23;
normal.normalize();
float r = d/_length;
if (treatVertexDataAsTemporary)
{
_intersections.insert(std::pair<const
float,TriangleIntersection>(r,TriangleIntersection(_index-1,normal,r1,0,r2,0,r3,0)));
}
else
{
_intersections.insert(std::pair<const
float,TriangleIntersection>(r,TriangleIntersection(_index-1,normal,r1,&v1,r2,&v2,r3,&v3)));
}
_hit = true;
}
};
}
///////////////////////////////////////////////////////////////////////////////////////////////////////////////////////
//
// LineSegmentIntersector
//
LineSegmentIntersector::LineSegmentIntersector(const osg::Vec3d& start, const
osg::Vec3d& end):
_parent(0),
_start(start),
_end(end)
{
}
LineSegmentIntersector::LineSegmentIntersector(CoordinateFrame cf, const
osg::Vec3d& start, const osg::Vec3d& end):
Intersector(cf),
_parent(0),
_start(start),
_end(end)
{
}
LineSegmentIntersector::LineSegmentIntersector(CoordinateFrame cf, double x,
double y):
Intersector(cf),
_parent(0)
{
set (cf, x, y);
}
void LineSegmentIntersector::set (CoordinateFrame cf, double x, double y)
{
switch(cf)
{
case WINDOW : _start.set(x,y,0.0); _end.set(x,y,1.0); break;
case PROJECTION : _start.set(x,y,-1.0); _end.set(x,y,1.0); break;
case VIEW : _start.set(x,y,0.0); _end.set(x,y,1.0); break;
case MODEL : _start.set(x,y,0.0); _end.set(x,y,1.0); break;
}
}
Intersector* LineSegmentIntersector::clone(osgUtil::IntersectionVisitor& iv)
{
if (_coordinateFrame==MODEL && iv.getModelMatrix()==0)
{
osg::ref_ptr<LineSegmentIntersector> lsi = new
LineSegmentIntersector(_start, _end);
lsi->_parent = this;
return lsi.release();
}
// compute the matrix that takes this Intersector from its CoordinateFrame
into the local MODEL coordinate frame
// that geometry in the scene graph will always be in.
osg::Matrix matrix;
switch (_coordinateFrame)
{
case(WINDOW):
if (iv.getWindowMatrix()) matrix.preMult( *iv.getWindowMatrix() );
if (iv.getProjectionMatrix()) matrix.preMult(
*iv.getProjectionMatrix() );
if (iv.getViewMatrix()) matrix.preMult( *iv.getViewMatrix() );
if (iv.getModelMatrix()) matrix.preMult( *iv.getModelMatrix() );
break;
case(PROJECTION):
if (iv.getProjectionMatrix()) matrix.preMult(
*iv.getProjectionMatrix() );
if (iv.getViewMatrix()) matrix.preMult( *iv.getViewMatrix() );
if (iv.getModelMatrix()) matrix.preMult( *iv.getModelMatrix() );
break;
case(VIEW):
if (iv.getViewMatrix()) matrix.preMult( *iv.getViewMatrix() );
if (iv.getModelMatrix()) matrix.preMult( *iv.getModelMatrix() );
break;
case(MODEL):
if (iv.getModelMatrix()) matrix = *iv.getModelMatrix();
break;
}
osg::Matrix inverse;
inverse.invert(matrix);
osg::ref_ptr<LineSegmentIntersector> lsi = new
LineSegmentIntersector(_start * inverse, _end * inverse);
lsi->_parent = this;
return lsi.release();
}
bool LineSegmentIntersector::enter(const osg::Node& node)
{
return !node.isCullingActive() || intersects( node.getBound() );
}
void LineSegmentIntersector::leave()
{
// do nothing
}
void LineSegmentIntersector::intersect(osgUtil::IntersectionVisitor& iv,
osg::Drawable* drawable)
{
osg::Vec3d s(_start), e(_end);
if ( !intersectAndClip( s, e, drawable->getBound() ) ) return;
// reset the clipped range as it can be too close in on the BB, and cause
missing due precission issues.
s = _start;
e = _end;
osg::TriangleFunctor<LineSegmentIntersectorUtils::TriangleIntersector> ti;
ti.set(s,e);
drawable->accept(ti);
if (ti._hit)
{
osg::Geometry* geometry = drawable->asGeometry();
for(LineSegmentIntersectorUtils::TriangleIntersections::iterator thitr
= ti._intersections.begin();
thitr != ti._intersections.end();
++thitr)
{
// get ratio in s,e range
float ratio = thitr->first;
// remap ratio into _start, _end range
ratio = ((s-_start).length() + ratio * (e-s).length()
)/(_end-_start).length();
LineSegmentIntersectorUtils::TriangleIntersection& triHit =
thitr->second;
Intersection hit;
hit.ratio = ratio;
hit.matrix = iv.getModelMatrix();
hit.nodePath = iv.getNodePath();
hit.drawable = drawable;
hit.primitiveIndex = triHit._index;
hit.localIntersectionPoint = s*(1.0f-ratio) + e*ratio;
hit.localIntersectionNormal = triHit._normal;
if (geometry)
{
osg::Vec3Array* vertices =
dynamic_cast<osg::Vec3Array*>(geometry->getVertexArray());
if (vertices)
{
osg::Vec3* first = &(vertices->front());
if (triHit._v1)
{
hit.indexList.push_back(triHit._v1-first);
hit.ratioList.push_back(triHit._r1);
}
if (triHit._v2)
{
hit.indexList.push_back(triHit._v2-first);
hit.ratioList.push_back(triHit._r2);
}
if (triHit._v3)
{
hit.indexList.push_back(triHit._v3-first);
hit.ratioList.push_back(triHit._r3);
}
}
}
insertIntersection(hit);
}
}
}
void LineSegmentIntersector::reset()
{
Intersector::reset();
_intersections.clear();
}
bool LineSegmentIntersector::intersects(const osg::BoundingSphere& bs)
{
// if bs not valid then return true based on the assumption that an invalid
sphere is yet to be defined.
if (!bs.valid()) return true;
osg::Vec3d sm = _start - bs._center;
double c = sm.length2()-bs._radius*bs._radius;
if (c<0.0) return true;
osg::Vec3d se = _end-_start;
double a = se.length2();
double b = (sm*se)*2.0;
double d = b*b-4.0*a*c;
if (d<0.0) return false;
d = sqrt(d);
double div = 1.0/(2.0*a);
double r1 = (-b-d)*div;
double r2 = (-b+d)*div;
if (r1<=0.0 && r2<=0.0) return false;
if (r1>=1.0 && r2>=1.0) return false;
// passed all the rejection tests so line must intersect bounding sphere,
return true.
return true;
}
bool LineSegmentIntersector::intersectAndClip(osg::Vec3d& s, osg::Vec3d&
e,const osg::BoundingBox& bb)
{
// compate s and e against the xMin to xMax range of bb.
if (s.x()<=e.x())
{
// trivial reject of segment wholely outside.
if (e.x()<bb.xMin()) return false;
if (s.x()>bb.xMax()) return false;
if (s.x()<bb.xMin())
{
// clip s to xMin.
s = s+(e-s)*(bb.xMin()-s.x())/(e.x()-s.x());
}
if (e.x()>bb.xMax())
{
// clip e to xMax.
e = s+(e-s)*(bb.xMax()-s.x())/(e.x()-s.x());
}
}
else
{
if (s.x()<bb.xMin()) return false;
if (e.x()>bb.xMax()) return false;
if (e.x()<bb.xMin())
{
// clip s to xMin.
e = s+(e-s)*(bb.xMin()-s.x())/(e.x()-s.x());
}
if (s.x()>bb.xMax())
{
// clip e to xMax.
s = s+(e-s)*(bb.xMax()-s.x())/(e.x()-s.x());
}
}
// compate s and e against the yMin to yMax range of bb.
if (s.y()<=e.y())
{
// trivial reject of segment wholely outside.
if (e.y()<bb.yMin()) return false;
if (s.y()>bb.yMax()) return false;
if (s.y()<bb.yMin())
{
// clip s to yMin.
s = s+(e-s)*(bb.yMin()-s.y())/(e.y()-s.y());
}
if (e.y()>bb.yMax())
{
// clip e to yMax.
e = s+(e-s)*(bb.yMax()-s.y())/(e.y()-s.y());
}
}
else
{
if (s.y()<bb.yMin()) return false;
if (e.y()>bb.yMax()) return false;
if (e.y()<bb.yMin())
{
// clip s to yMin.
e = s+(e-s)*(bb.yMin()-s.y())/(e.y()-s.y());
}
if (s.y()>bb.yMax())
{
// clip e to yMax.
s = s+(e-s)*(bb.yMax()-s.y())/(e.y()-s.y());
}
}
// compate s and e against the zMin to zMax range of bb.
if (s.z()<=e.z())
{
// trivial reject of segment wholely outside.
if (e.z()<bb.zMin()) return false;
if (s.z()>bb.zMax()) return false;
if (s.z()<bb.zMin())
{
// clip s to zMin.
s = s+(e-s)*(bb.zMin()-s.z())/(e.z()-s.z());
}
if (e.z()>bb.zMax())
{
// clip e to zMax.
e = s+(e-s)*(bb.zMax()-s.z())/(e.z()-s.z());
}
}
else
{
if (s.z()<bb.zMin()) return false;
if (e.z()>bb.zMax()) return false;
if (e.z()<bb.zMin())
{
// clip s to zMin.
e = s+(e-s)*(bb.zMin()-s.z())/(e.z()-s.z());
}
if (s.z()>bb.zMax())
{
// clip e to zMax.
s = s+(e-s)*(bb.zMax()-s.z())/(e.z()-s.z());
}
}
// osg::notify(osg::NOTICE)<<"clampped segment "<<s<<" "<<e<<std::endl;
// if (s==e) return false;
return true;
}
/* -*-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 OSGUTIL_LINESEGMENTINTERSECTOR
#define OSGUTIL_LINESEGMENTINTERSECTOR 1
#include <osgUtil/IntersectionVisitor>
namespace osgUtil
{
/** Concrete class for implementing line intersections with the scene graph.
* To be used in conjunction with IntersectionVisitor. */
class OSGUTIL_EXPORT LineSegmentIntersector : public Intersector
{
public:
/** Construct a LineSegmentIntersector the runs between the specified
start and end points in MODEL coordinates. */
LineSegmentIntersector(const osg::Vec3d& start, const osg::Vec3d& end);
/** Construct a LineSegmentIntersector the runs between the specified
start and end points in the specified coordinate frame. */
LineSegmentIntersector(CoordinateFrame cf, const osg::Vec3d& start,
const osg::Vec3d& end);
/** Convenience constructor for supporting picking in WINDOW, or
PROJECTION coordinates
* In WINDOW coordinates creates a start value of (x,y,0) and end
value of (x,y,1).
* In PROJECTION coordinates (clip space cube) creates a start value
of (x,y,-1) and end value of (x,y,1).
* In VIEW and MODEL coordinates creates a start value of (x,y,0) and
end value of (x,y,1).*/
LineSegmentIntersector(CoordinateFrame cf, double x, double y);
struct Intersection
{
Intersection():
ratio(-1.0),
primitiveIndex(0) {}
bool operator < (const Intersection& rhs) const { return ratio <
rhs.ratio; }
typedef std::vector<unsigned int> IndexList;
typedef std::vector<double> RatioList;
double ratio;
osg::NodePath nodePath;
osg::ref_ptr<osg::Drawable> drawable;
osg::ref_ptr<osg::RefMatrix> matrix;
osg::Vec3d localIntersectionPoint;
osg::Vec3 localIntersectionNormal;
IndexList indexList;
RatioList ratioList;
unsigned int primitiveIndex;
const osg::Vec3d& getLocalIntersectPoint() const { return
localIntersectionPoint; }
osg::Vec3d getWorldIntersectPoint() const { return matrix.valid() ?
localIntersectionPoint * (*matrix) : localIntersectionPoint; }
const osg::Vec3& getLocalIntersectNormal() const { return
localIntersectionNormal; }
osg::Vec3 getWorldIntersectNormal() const { return matrix.valid() ?
osg::Matrix::transform3x3(osg::Matrix::inverse(*matrix),localIntersectionNormal)
: localIntersectionNormal; }
};
typedef std::multiset<Intersection> Intersections;
inline void insertIntersection(const Intersection& intersection) {
getIntersections().insert(intersection); }
inline Intersections& getIntersections() { return _parent ?
_parent->_intersections : _intersections; }
inline Intersection getFirstIntersection() { Intersections&
intersections = getIntersections(); return intersections.empty() ?
Intersection() : *(intersections.begin()); }
inline void setStart(const osg::Vec3d& start) { _start = start; }
inline const osg::Vec3d& getStart() const { return _start; }
inline void setEnd(const osg::Vec3d& end) { _end = end; }
inline const osg::Vec3d& setEnd() const { return _end; }
/** Method to set the start and end points to support picking in
WINDOW, or PROJECTION coordinates
* In WINDOW coordinates creates a start value of (x,y,0) and end
value of (x,y,1).
* In PROJECTION coordinates (clip space cube) creates a start value
of (x,y,-1) and end value of (x,y,1).
* In VIEW and MODEL coordinates creates a start value of (x,y,0) and
end value of (x,y,1).*/
void set (CoordinateFrame cf, double x, double y);
public:
virtual Intersector* clone(osgUtil::IntersectionVisitor& iv);
virtual bool enter(const osg::Node& node);
virtual void leave();
virtual void intersect(osgUtil::IntersectionVisitor& iv, osg::Drawable*
drawable);
virtual void reset();
virtual bool containsIntersections() { return !_intersections.empty(); }
protected:
bool intersects(const osg::BoundingSphere& bs);
bool intersectAndClip(osg::Vec3d& s, osg::Vec3d& e,const
osg::BoundingBox& bb);
LineSegmentIntersector* _parent;
osg::Vec3d _start;
osg::Vec3d _end;
Intersections _intersections;
};
}
#endif
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