Re: [eigen] Do we need geometry refactoring?

[Hauke Heibel <hauke.heibel@xxxxxxxxxxxxxx>]

On Tue, Aug 3, 2010 at 2:33 AM, Benoit Jacob <jacob.benoit.1@xxxxxxxxx> wrote:
> Eeek, a lot of people will be expecting that Transform3f * Vector3f
> gives a Vector3f, I didn't think about this.
>
> This is a really big argument in favor of the old default Affine for
> Transform. What do you think about reverting to Affine?

Absolutely nothing. :)

When outvoted, I am ready to switch back but let's just look at the
list of pros/cons.

pros for switching back:
- Some users are happy because their old code keeps working

cons against switching back:
- It is unintuitive that the most generic Transformation is affine
- Some users are unhappy because expectedly correct code like this
produces wrong results (one of my strongest arguments)

Transform3f T( some_projective_4x4_matrix );
Vector3f v;
T*v

"Hmm, and I was sure I read that Transform3f's model non-linear
transformations!??"
- In 90% of the cases, we can be hope (I admit this is not a strong
argument) that the users will get a compile time error for the example
in question because the fixed size dims are not fitting (v' = T*v when
T is projective)
- Last chance to get things right since Eigen 3 will anyways break
lots of Eigen 2 code or we are stuck with this forever
- It is the right thing to do .... ;)

Ok, I am passing the choice back to you and other people on the list.
As I said, outvote me and I will revert this change.

Regards,
- Hauke