problems with isect
wrvo (WRVO++at++chevron.com)
Mon, 11 May 1998 15:45:24 -0700
I am having trouble using isect. The problem is that it does not return the
correct pick. I have set up the eye direction and other things in the
pfSegSet and added a discFunc callback to see what is happening. The object
that I'm isect'ing with is a simple cube and all quads of the cube have back
face culling turned off. The six quads are the only thing in the model that
has a non-zero isect mask (I've checked this by descending the scene graph
and printing the mask for each node). I've also checked that the all the
nodes have the isect cache updated and the bounding boxes are correct. With
this configuration (back face turned off and a simple cube), then the
discFunc should find two isect's and take the one closest to me. But what
I'm finding is that I frequently get is only one isect, not two. And it is
usually the one in the back of the model. If I turn back face culling on,
then when I was getting one hit, I get none.
I am at a loss to explain this behavior. Does anyone have any insight they
could provide as to why this is happening or areas to look into?
All help would be greatly appreciated.
Bill Volz - Senior Research Geophysicist
Chevron Petroleum Technology
Voice: (281)-596-2059 Fax: (281)-493-7088
=======================================================================
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 - 17:57:23 PDT