Am Wed, 25 Apr 2007 18:49:09 -0400 schrieb Alain:

> You have "normal" textures.
> You have interior_texture. (an optional element) Add "coincident_texture"
> (as another optional element) with a coincidence_treshold parameter
> (defaulting to epsilon*2 for example) defining the maximum gap that can
> separate the surfaces to be considered as coincident.
> 
> For those unfamiliar with the term, the "epsilon" value is the smalest
> value you can have before it's considered as zero.

I know epsilon as the lowest number, where the floating point
representation of the sum of this number and 1 and 1 is greater than 1.
Checking whether to floating point numbers are roughly the same is still
not that easy. If you want to be really correct abs(a-b) < epsilon is not
enough, because epsilon is more like a factor. It all depends on the
calculations done with a and b before.

I think that syntax would get us into a great mess. Is that texture
applied on both sides of these surfaces? Where will the ray be reflected
and transmitted? In my opinion a sort of CSG with more options than
"inside" and "outside" would be better.

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