Re: quick comments on Matrix

On Fri, Mar 15, 2013 at 10:57 PM, Gregg Tavares <gman@google.com> wrote:
> I don't want to bikeshed here but in my limited circle a Point doesn't have
> a W. A Point represents a place in 2D or 3D space. Mathematically you can't
> add 2 points but you can add 2 vectors. Subtracting 2 points gives you a
> vector. Adding a vector to a point transforms a point. Adding 2 vectors
> gives another vector. That might just be my experience and not connected to
> any reality but I've seen the distinction in libraries I've used. It's also
> related the suggestion for transformPoint vs transformVector.

That's what the w indicates - if it's 0 it's a vector, if it's 1 it's a point.

~TJ

Received on Saturday, 16 March 2013 06:05:16 UTC