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Subject: [ggl] Efficient rotation about a point
From: Barend Gehrels (Barend.Gehrels)
Date: 2009-12-02 03:54:47

Hi Lee,

> I wonder, is there really any benefit in having composable-matrix +
> ublas_transformer over having
> composable (affine) transformers?
> As a user, I'm looking at the existing rotate/translate/scale
> transformers and being frustrated by the
> thought "if only I could compose these things!". Is matrix +
> ublas_transformer really the answer to
> that?

We don't want to duplicate functionality from uBlas or another matrix
library, but use it.

I agree that the rotate/scale/translate might not be that useful.
However, they are tiny derivatives from ublas_transformer, only calling
its constructor. The ublas_transformer has a constructor taking 9
values, so you call it also yourself. And we'll add a constructor taking
a matrix.

The ublas transformers are not the only things, the generic design is
that the generic "transform" function take a strategy (which can be a
matrix, but also a projection, or anything you create yourself).

Regards, Barend

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