🚀 go-pugleaf

Steve Piner wrote:
> 
> :> Sorry to quibble, but...
> :>
> :>    A VECTOR IS NOT A POINT!!!!
> :>
> :> Now back to our regular program.
> :
> :Points are vectors.
> 
> A vector is a direction with a magnitude.  A point is a direction and a
> distance *from an origin*.  Vectors are not relative to anything else, points
> are.
> 
> Although the two can be coded interchangeably they are not the same thing.

THIS is the interesting part: A point is 3 numbers, so is a vector. Sure, you can 
set up your system to separate points and vectors if you want. But I often think 
that is unnecessary.

What if you subtract two points? (C++). Do you get a point, or a vector?

The "real" answer is "a vector". But I've seen 3D libraries that religiously keep 
vectors and points separate (making some creative constructs difficult, just for 
the sake of semantical clarity), and yet others that use the same class/structure 
for both, which, IMHO, is "easier", but can get you into difficult semantics.

It's a choice. You make it.
 
> Steve Piner
> --
>  ____ ____
> / __//___ \  Steve Piner - spiner@sans.vuw.ac.nz
> \__ \ |  _/
> /___/ |_|    [This post is finished - stop reading now]

-- 
Hakan "Zap" Andersson | http://www.lysator.liu.se/~zap | Q: 0x2b | ~0x2B
Job:  GCS Scandinavia | Fax:   +46 16 96014            | A: 42
zap@lysator.liu.se    | Voice: +46 16 96460            | "Whirled Peas"
------------------------------------------------------------------------
GENIUS - Mechanical Design for AutoCAD - http://www.kuai.se/~zap/genius
------------------------------------------------------------------------
Never underestimate the bandwidth of a speeding truck full of DAT tapes.
------------------------------------------------------------------------