Re: [openvrml-develop] Re: VrmlMatrix

[Sylvain C. <syl...@to...>]

While at matrix transform,
could it be possible to implement the VRMLMatrix in a way that it will be
"open" to a reimplementation of the VRML1.0 MatrixTransform - access to *all*
of the 16 values?
I intend to create a VRML97 like implemetation of this matrix, all field
should be dynamicaly accessible.
I know that it could lead to implemetation problems (but not sure of which -
non-invertible transform?, impossible space?) and thats why it have been
dropped from VRML97; cryptic, complicated to implement and barely used.

Actually, on the pc, I only know of VRMLView that can display those transforms
correctly, all the others either ignore or cant display objects transformed
with projection parameters included in the matrix. Worse, some toolkit even
have them illegal (java3D). One option will be to link Ellipsis to
OpenInventor and add that extra MatrixTransform as a new VRML97 syntax like
node with eventIn's/out's. The other option will be having you guys leave open
the matrix (not enforcing affine only transform as in java3D) at least at the
very low level so someone could implement back a fully functionnal matrix
transform.
I hope this can be feasible with openvrml.

Sylvain Carette
VRML designer-composer

"S.K.Bose" wrote:

> On 12 Oct 2001, Braden McDaniel wrote:
>
> > I was just reading your ChangeLog comments, and you say
> >
> >         * A New Class VrmlMatrix is implemented. Here the format
> >           is same as OpenGL standard. So this matrix can be used
> >           transparently as OpenGL matrix.
> >
> > OpenGL matrices are column-major, whereas VrmlMatrix is row-major. I'd
> > like to keep VrmlMatrix row-major, but that difference should be kept in
> > mind when feeding them to OpenGL.
> >
>
> You're right of course.
>
> I mean to say here the rotation, translation, scaling, .....all settings
> are according to OpenGL format.
>
> Bose
>
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