Andrew Clinton <ajc### [at] uwaterlooca> wrote:
> Okay, I define it to be one that obeys the law of reflection at all points
> (not just one).  Of course you can define it any way you'd like, but I
> don't think you'd argue that this definition is "more true" than the way
> reflection maps work :-)

  Reflection maps work pretty well assuming that none of the reflected
scene is too close to the reflecting object.
  If the rest of the scene is far enough from the reflecting object,
there's practically no difference between reflection maps and reflection
by raytracing (give or take some pixelation).

  Reflection maps have the advantage that they are very fast to render
(it can be done in real-time) and many effects can be done for free with
them (eg. blurred reflection, phong highlights, etc).
  They have the disadvantage that they don't work well if an object
being reflected is too close to the reflecting object, and inter-reflection
between two or more reflecting surfaces is not trivial.
  (One could think that an additional disadvantage is that it only works
with flat polygons, but in fact that's not a limitation of reflection
maps: Nothing stops you from using reflection maps with any surface you
are eg. raytracing. Of course it often doesn't make sense, specially in
raytracing, but it's perfectly possible.)

-- 
plane{-x+y,-1pigment{bozo color_map{[0rgb x][1rgb x+y]}turbulence 1}}
sphere{0,2pigment{rgbt 1}interior{media{emission 1density{spherical
density_map{[0rgb 0][.5rgb<1,.5>][1rgb 1]}turbulence.9}}}scale
<1,1,3>hollow}text{ttf"timrom""Warp".1,0translate<-1,-.1,2>}//  - Warp -

Post a reply to this message