OBJ loader/Builder BUG?

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Scott McMillan (scott++at++ht.com)
Wed, 2 Jul 1997 12:01:16 -0400 (EDT)


I have been playing with the OBJ loader in version 2.0.x and have
encountered what appears to be bug:

When I load an OBJ model without normals (pfdBuilder creates them) and I
specify a material with a reflective texture. The model has a lot of large
flat surfaces made up of a few triangles. The reflections are really messed
up -- e.g. coplanar adjacent faces show drastically different reflections.
It is like the normals have not been computed correctly for the texgen
operation. The normals shown in perfly seem to be correct so I don't know
exactly where the bug(?) is.

I am in the process of writing an OBJ loader that preserves indexed vertex
and normal lists (for future morphing applications). It doesn't build the
tristrips yet. It does compute normals (if desired) and reflection maps the
object properly using straight OpenGL calls so I don't think it is a problem
with OpenGL.

So is this an unexpected interaction between generation of normals,
stripifying, smooth shading and reflective textures? Or is it a real bug.

Thanks in advance,

scott

-- 
  Scott McMillan  |    HT Medical, Inc.   | Developing medical VE's
   scott++at++ht.com   |   http://www.ht.com   | surgical simulations
 Ph: 301-984-3706 |6001 Montrose Rd., #902| and surgery simulation
Fax: 301-984-2104 |  Rockville, MD 20852  | creation tools.

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