On 29 Jan 2002 19:02:36 -0500, Ron Parker <ron### [at] povrayorg>
wrote:

>You don't need a Normal_At(Point) method if you instead compute and save
>the normal when you retrieve the intersection; for some objects this is less
>time-consuming and less ambiguous.

OK, OK, but for some it is not. Maybe something like:

#define Returned_Normal N

if ((!N.x) && (!N.y) && (!N.z) )
  N = ThisObject.Normal_At(Intersection_Point);

You know, I never thought of it this way - that by the maths of it,
some objects will readily provide the normal while intersection
testing. Now there's something to wake me up :)


Peter Popov ICQ : 15002700
Personal e-mail : pet### [at] vipbg
TAG      e-mail : pet### [at] tagpovrayorg

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