Re: [boost] proposal for efficient geom. vector class

From: Marcelo E. Magallon (mmagallo_at_[hidden])
Date: 2003-05-22 10:00:40

On Thu, May 22, 2003 at 12:48:42PM +0200, Rene Jager wrote:
 
 > >  >    "Computer Graphics using Open GL" F.S. Hill Prentice Hall
 > >  >    "Computer Graphics Principles and Practise in C", Foley
 > >  >    et.al.  Addison Wesley
 > > 
 > >  "Down the graphics pipeline" by Blinn is also a good reference for
 > >  this kind of thing.
 > 
 > why only looking at geometry classes/functions from a computer
 > graphics point of view? why not from robotics? things like position,
 > orientation, mapping, transformation, translation, rotation...

 Because it's the same?  The only thing that might be different is the
 use of homegeneous coordinates / projective space.  Engineers tend to
 think of translations and rotations as two different things, while
 computer graphics people think of them as the same operation: matrix
 multiplication.  Perhaps another point of divergence: I can imagine
 Physicists (which I am also one) whishing 4d vectors to be initialized
 to (0, 0, 0, 0) while computer graphics people might want it to be (0,
 0, 0, 1).  The former might think that casting 4d-vectors to 3d-vectors
 means just taking the spatial component of the original vector.  The
 later will think that it means returning (x/w, y/w, z/w).  The former
 will want to differentiate psedo-vectors, too.  The later might wish to
 differentiate between vectors and normals (because they transform
 differently).

 Marcelo