Re: [boost] Geometry/Vector Lib

From: Olivier Grant (olivier.grant_at_[hidden])
Date: 2006-09-21 07:12:25

Quick update, see below :

On 9/20/06, Olivier Grant <olivier.grant_at_[hidden]> wrote:

> On 9/20/06, james.jones_at_[hidden] <james.jones_at_[hidden]
> > wrote:
> >
> > From: "Olivier Grant" < olivier.grant_at_[hidden]>
> > On 9/20/06, Walter Landry <wlandry_at_[hidden]> wrote:
>
>
Also, if a 2D vector is a 3D vector with z=0, and a 3D vector is a 4D vector
> > with w=1, "and so on by extension", then how would a 4D vector compare with
> > a 5D vector? I don't get the extension. When you first posted your example,
> > I assumed you'd made a typo when you set w=1, but now I think you did that
> > on purpose. Why wouldn't w=0?
>
>
> I was thinking of 3D control points, but that was a bad example. I just
> wanted to point out that the implementation allowed users to define specific
> default values for each coordinate.
>

Actually, It also comes from OpenGL. vertices and vectors are kind of
similar, and when specifying vertex data in OpenGL, you can omit the z and w
coordinates, that respectivly take values 0 and 1.

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>
> Thanks for your comments and questions,
>
> Olivier.
>
>