ConvertAdjacencyToPointReps

Does nobody know? Somebody has to know.

i find it at http://www.xmission.com/~legalize/book/archive/usenet.cgi?14110

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> What is the point representative data? Is it vertex index?

Yes.
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Yes, it is an array of vertex indices.

If you think of two adjacent triangles which share an edge. Lets say triangle ABC and DEF share an edge BC/DE like:

---CD---
--/||\--
-A-||-F-
--\||/--
---BE--- (the ''-''s are just for spacing)

Vertices: ABCDEF
Adjacency: -1-0--

Vertices B and E are co-located (since we know the edge are shared), but may have different vertex indices, since they might have different normals, texture coordinates, colors, etc.. Vertices C and D are co-located too.

When you convert to point-reps, a single vertex index will be used to represent these co-located vertex. For example, if you created point reps for the triangles above, it would probably look like:

Vertices: ABCDEF
Point-reps: 012215

Note that B and E are both given the value 1. The fact that they share a value indicates that they are co-located. Since 1 is the index of B, B is called the point-representative of B and E.

The same is true of C and D. In this example, C is the point-representative of C and D. It is not really important that C was picked instead of D to be the representative. Either would work just as well.

Hope this all makes some sense.

xyzzy