Florin Herinean wrote:
I can confirm that DirectX version is behaving correctly regarding the
specular lighting effect, as in the attached image. However, you can clearly
see from the image that DirectX version has it's own bigger problems which
makes it unusable for me: it is not honouring the Back-face normal flip
option in the PolygonAttributes constructor (see the very dark front facing
faces). Is this a bug in j3d or simply directx layer doesn't know about
back-face normal flip ?


Hi Florin,


We've email'd in the past about LEGO and J3D. It looks like your
code is coming along nicely.

For the longest time I was also stuck on a problem that is similiar
to what you are seeing I think. Does this work corectly for you in
OGL?

The Flip Normals flag didn't seem to ever (OGL or D3D) do what I
wanted it to do.

My code currently rewind all non CCW polygons to be CCW, and
uses those points to calculate Normals. I then used CULL_BACK
to elininate the back faces. Also if a sub file was referenced
with 0 BFC INVERTNEXT, I switched to CULL_FRONT, so that it was
rendered facing the other way.

Similiar to what you are seeing, these polygons that are done
with CULL front, still have the normals facing into the object,
so that even though the culling worked correctly the lighting
was shaded wrong. I originally thought that the backface normal
flipping would flip these normals for me automatically, but
someone in the J3D group here at sun explained to me why it
wouldn't work (not even in OGL) - I don't remember the
explaination right now.

I ended up solving this by computing 2 sets of normals for each
polygon, and then in addition to switching from CULL_BACK to
CULL_FRONT when I see a 0 BFC INVERTNEXT, I also switch which
normals I attach to the geometry array.

It's not as elegant a solution as I might have liked, but it
does work for me.

-Kyle


-- _ -------------------------------ooO( )Ooo------------------------------- Kyle J. McDonald (o o) Systems Support Engineer Sun Microsystems Inc. ||||| Enterprise Server Products [EMAIL PROTECTED] 1 Network Drive BUR03-4630 \\\// voice: (781) 442-2184 Burlington, MA 01803 (o o) fax: (781) 442-1542 -------------------------------ooO(_)Ooo-------------------------------

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