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From: Peter Dimov (pdimov_at_[hidden])
Date: 2004-11-07 19:22:10


Valentin Samko wrote:
>> The CG literature I've read uniformly treated points and
>> vectors as different beasts.
> I am not a CG expert, so I do not know why this is so in CG
> literature, probably this approach is more convenient to describe
> some CG problems. I am only familiar with dimensionality reduction
> aspects of CG, which treat points and vectors as the same beasts.

That's because in CG one can't get away with treating points and vectors
uniformly. Both points (positions in space) and vectors (surface normals at
a particular position) are integral parts of CG, but moving an object only
affects positions, not normals.

That said, in GUI (and 2D positioning in general) I've always been able to
get away with using vectors everywhere (and calling them points, of course.)
I wonder whether the convenience is a win over the extra type safety in this
context.


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