contest fix

[Henry Cejtin]

I  looked  at the chess board with my fix in, and it is much much better, but
the cones on the tops of knights still have bad reflections.  As one example,
the  base  of  the cone (which forms the back of the knight head) seems to be
flat matt in our version, while  in  the  winner  version  it  is  some  kind
interesting pattern.  It is placed on there by the figureSurface function.

As  to  the scratch marks and my gross fix, I now remembered my notion of how
this should work, and it still should be fine.  The point is that you  never,
in  the  end,  see  a ray leaving a surface unless it started on the surface.
The reason is that they told us that they would not start with the eye inside
an  object,  so  the  first intersection is entering, and you never go inside
anything: you always bounce or stop.

Thus the only correction to the basic  objects  is  to  make  sure  that  the
startInside  is  set  correctly:  If a ray never intersects an object (either
forwards or backwards) then you can just do some  measure  of  if  it  starts
inside.   If  you  are  wrong  (because it starts very close) that is ok.  If
going forward ever intersects, then if it is going in you started out and  if
it  is  going  out you started in.  (Note the case where it is tangent (i.e.,
the dot product of the direction and the normal is 0) does not count as a hit
at  all.)  If the forward never intersects but the backwards does then you do
the same with the notion reversed.

Now, while you are following a ray, if the first intersection exists  and  is
leaving, ignore it.  You must have started on that very object.

Viola.   I  remember  when  I  figured this out during the contest, but I got
confused at some point, probably when I switched to  the  basic  objects  and
described what should be done to you Stephen.  Definitely too bad.

Any  way, I'm pretty sure that at least part of the remaining cone problem is
your not passing on the texture map for the plane at the base of the cone.  I
don't know if that is everything though.