Tim Moore (moore++at++herschel.pfgroup.com)
Wed, 5 Feb 1997 21:54:10 -0800 (PST)
The problem might be that, as u r mirroring the X co-ordinates, your
polygon/face 's front plan goes to back, and so Performer engine HIDES it
from u and so u see is only BLACK..
Close. The order of the polygon vertices has been changed by the
flip, so front is no longer front. You can either change all the
vertices around in the pfGeoSet, which is a big pain, or you can stick
glFrontFace (GL_CW) in a pre-draw callback to change the vertex order
to clockwise, and glFrontFace (GL_CCW) in a post-draw callback to
reset things for all the other geometry.
I'm not sure what the IrisGL equivalent is, or if there's a Performer
encapsulation of it...
Tim
> To: info-performer++at++sgi.com
> Subject: reflecting GeoSets causes shading to malfunciton
> Hello Performers:
>
> I have a GeoSet with normals bound per vertex. I am trying to reflect the
> GeoSet across the YZ plane by negating the X-component of all the coords and
> negating the X-component of all the normals. Shading does not work after I
> do this. The geometry is located properly, but the surfaces appear black for
> the most part. Anyone know why?
>
>
> Dave Heskamp
>
=======================================================================
List Archives, FAQ, FTP: http://www.sgi.com/Technology/Performer/
Submissions: info-performer++at++sgi.com
Admin. requests: info-performer-request++at++sgi.com
This archive was generated by hypermail 2.0b2 on Mon Aug 10 1998 - 17:54:36 PDT