In this case the matrix being applied needn't be a rotation matrix.
Robert.
On 10/3/06, Alberto Luaces <
[EMAIL PROTECTED]> wrote:
What John says is true at least for 3x3 orientation matrices, which I think is
the case by reading the code. In that case, the transpose and the inverse of
a transformation matrix are equal (they are orthogonal).
Both of you may get correct results because (R*p)t = pt*Rt, being "t" the
transpose symbol and R, p the Rotation matrix and the Point vector
respectively. I think John's way is simpler and possibly faster.
Alberto
El Martes, 3 de Octubre de 2006 10:27, Robert Osfield escribió:
> Hi John,
>
> To transform planes and normals you mulitple by the transpose of the
> inverse of a matrix, to transform vertices you multiple by the matrix
> directly. The code you see does the trick of doing the transpose by doing
> doing switching the post and pre multiple order.
>
> I also haven't see switching normal orientations before, this makes me
> wonder if there isn't something else wrong that you usage is uncovering.
> Could you provide a model that reproduces it?
>
> Robert.
>
>
> On 10/3/06, John Aughey <[EMAIL PROTECTED]> wrote:
> When the optimizer reduces static transforms, it multiplies the verticies
> and normals by the current transformation matrix. It uses
> TransformAttributeFunctor to do this. However, it's transforming the
> normals backwards. The comment in the TransformAttributeFunctor.cpp line
> 43 says to post mult by inverse for normals which makes no sense. The
> normals should be transformed the same way the verticies are. If you
> change the matrix from _im to _m on line 44, then the model optimizes
> correctly with the normals pointing the correct way.
>
> If you want, I can submit a patch for just this.
>
> John
_______________________________________________
osg-users mailing list
[email protected]
http://openscenegraph.net/mailman/listinfo/osg-users
http://www.openscenegraph.org/
_______________________________________________ osg-users mailing list [email protected] http://openscenegraph.net/mailman/listinfo/osg-users http://www.openscenegraph.org/
