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;
}
}
double distanceLineOnPlane(const osg::Vec3d& src, const osg::Vec3d& dst, const osg::Plane& plane)
{
// can be optimized -> dst-src is a axis aligned vector
return (-plane[3] - plane.dotProductNormal(src))/plane.dotProductNormal(dst - src);
}