hi Hartwig,
"Hartwig Wiesmann" writes:
[...]
> osg::Plane::makeUnitLength(void) is not only normalizing the plane's normal
> but also scaling the distance between the point of origin and the plane.
> Actually, osg::Plane::makeUnitLength(void) should be implemented like
>
> inline osg::Plane::makeUnitLength(void)
> {
> value_type inv_length = 1.0 / sqrt(_fv[0]*_fv[0] + _fv[1]*_fv[1]+
> _fv[2]*_fv[2]);
> _fv[0] *= inv_length;
> _fv[1] *= inv_length;
> _fv[2] *= inv_length;
> }
>
> if it should do only what the method's name suggests the method does.
This could be only an interpretation issue, but let me add some points :)
* The original function is not scaling the distance between the point of
origin and the plane. Rather than that, it is preserving that
distance. Think of the trivial case of a plane perpendicular to X with
an offset of two units from the origin. We could write it as 2x-4=0,
for example. If you normalize the vector but don't scale the fourth
component, the resulting plane is different: x-4=0.
* When I read "osg::Plane::makeUnitLength" I think about "normalize the
vector of the plane". What would be the purpose of having a different,
only parallel plane after the use of that function?
--
Alberto
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