intersectRayLineSegment

Determine whether the ray with given <code>origin</code> and direction <code>dir</code> intersects the undirected line segment given by the two end points <code>a</code> and <code>b</code>, and return the value of the parameter <i>t</i> in the ray equation <i>p(t) = origin + t * dir</i> of the intersection point, if any. <p> This method returns <code>-1.0</code> if the ray does not intersect the line segment.

@see #intersectRayLineSegment(double, double, double, double, double, double, double, double)

@param origin the ray's origin @param dir the ray's direction @param a the line segment's first end point @param b the line segment's second end point @return the value of the parameter <i>t</i> in the ray equation <i>p(t) = origin + t * dir</i> of the intersection point, if the ray intersects the line segment; <code>-1.0</code> otherwise