Re: Intersection testing on scaled objects

New Message	Reply	Date view	Thread view	Subject view	Author view

Jim Helman (jimh++at++surreal)
Thu, 16 Mar 95 21:49:47 -0800

Next message: Fischler: "Re: More on simpleviewer"
Previous message: Jim Helman: "Re: strange seg-fault under IRIX5.3"
In reply to: Michael J. Smith: "strange seg-fault under IRIX5.3"

intersect.c works fine with scales as far as I can tell. I
think this is just an issue of coordinate frames. The point
returned in the pfHit is in object coordinates. If you want
scene coordinates, as is appropriate for ground following in
intersect.c, you need to transform the returned point by the
xform returned in the pfHit, i.e.

        if (isect)
        {
                pfVec3 pnt, xpnt;
                pfMatrix xmat;
                pfQueryHit (*hits[0], PFQHIT_POINT, &pnt);
                pfQueryHit (*hits[0], PFQHIT_XFORM, xmat);
                pfXformPt3(xpnt, pnt, xmat);
                shared->zval = xpnt[PF_Z] + 0.5;
        }

rgds,

-jim helman

jimh++at++surreal.asd.sgi.com
415/390-1151

Next message: Fischler: "Re: More on simpleviewer"
Previous message: Jim Helman: "Re: strange seg-fault under IRIX5.3"
In reply to: Michael J. Smith: "strange seg-fault under IRIX5.3"

New Message	Reply	Date view	Thread view	Subject view	Author view

This archive was generated by hypermail 2.0b2 on Mon Aug 10 1998 - 17:51:05 PDT

This message has been cleansed for anti-spam protection. Replace '++at++' in any mail addresses with the '@' symbol.