unsigned
GeoMath::intersectLineWithPlane(const osg::Vec3d& p0,
const osg::Vec3d& p1,
const osg::Plane& plane,
osg::Vec3d& out_p)
{
osg::Vec3d V = p1-p0;
V.normalize();
double denom = plane.dotProductNormal(V);
// if N*V == 0, line is parallel to the plane
if ( osg::equivalent(denom, 0.0) )
{
// if p0 lies on the plane, line is coincident with plane
// and intersections are infinite
if ( osg::equivalent(plane.distance(p0), 0.0) )
{
out_p = p0;
return 2;
}
else
{
// line does not intersect plane.
return 0;
}
}
else
{
// one intersection:
double t = -(plane.dotProductNormal(p0) + plane[3])/denom;
out_p = p0 + V*t;
return 1;
}
}
PolytopeIntersection(unsigned int index, const CandList_t& cands, const osg::Plane &referencePlane) :
_maxDistance(-1.0), _index(index-1), _numPoints(0)
{
Vec3_type center;
for (CandList_t::const_iterator it=cands.begin(); it!=cands.end(); ++it)
{
PlaneMask mask = it->first;
if (mask==0) continue;
_points[_numPoints++] = it->second;
center += it->second;
value_type distance = referencePlane.distance(it->second);
if (distance > _maxDistance) _maxDistance = distance;
if (_numPoints==MaxNumIntesections) break;
}
center /= value_type(_numPoints);
_distance = referencePlane.distance( center );
}