Re: PFGS_POLYS problem
Fred Clyne (rock.csd.sgi.com!sgi.com!uunet.uu.net!ds9!octave!fred)
Fri, 10 Jan 1997 15:35:39 -0500
On Jan 10, 10:25am, Bruno Rassaerts wrote:
> Subject: PFGS_POLYS problem
>
> Hi,
>
> I know now the the problem that I had with perfly is caused by a bug in
> Performer 2.0 and that this problem is fixed in 2.0.2. But I stumbled on
> something else that's weird. In my application I want to draw a polygon
> with 5 vertices. The geoset of this polygon looks like this (printed
> with pfPrint)
>
> --------
> GeoSet: 0x180998e0 {
> Primitive: PFGS_POLYS, NON-INDEXED, pfPrims=1, glPrims=3,
> verts=5
> Attribute Bindings:
> PFGS_COLOR4=PFGS_OFF PFGS_NORMAL3=PFGS_PER_PRIM
> PFGS_TEXCOORD2=PFGS_OFF
> Attribute List Pointers:
> PFGS_COORD3: 0x180a5130
> PFGS_COLOR4: 0x0
> PFGS_NORMAL3: 0x180a5450
> PFGS_TEXCOORD2: 0x0
> Attribute Index List Pointers:
> PFGS_COLOR4: 0x0
> PFGS_NORMAL3: 0x0
> PFGS_TEXCOORD2: 0x0
> PFGS_COORD3: 0x0
> Strip Lengths: 5
>
> Prim Normal 0: NX: 0.000000 NY: -1.000000 NZ: 0.000000
> Coord 0: X: -1.750000 Y: 0.000000 Z: -1.300000
> Coord 1: X: 0.800000 Y: 0.000000 Z: -0.950000
> Coord 2: X: 1.550000 Y: 0.000000 Z: 0.700000
> Coord 3: X: -1.300000 Y: 0.000000 Z: 1.650000
> Coord 4: X: -2.350000 Y: 0.000000 Z: 0.600000
>
> } GeoSet: 0x180998e0
> --------
>
> The problem that Performer draws this polygon with a hole in it. I
> attached a small picture (4k) that shows this problem. (Sorry for
> putting a binary on the mailing list but is was hard to explain
> otherwise) The polygon was highlighted with PFHL_LINES so that you can
> see the edges.
>
> Note: I am still using Performer 2.0 on an ONYX RE2 IRIX 6.2
>
> Thanks,
> --
> // Bruno Rassaerts - EDM (Expertisecentrum Digitale Media)
> ('> Wetenschapspark 2 - B-3590 Diepenbeek - Tel: +32-(0)11268411
> /rr Fax: +32-(0)11269400 - eMail: brassaer++at++luc.ac.be
> *\))_ URL: http://www.luc.ac.be/~brassaer/
>
> [ Attachment (image/jpeg): "snap.jpg" 5081 bytes
> Encoded with "base64" ]
>-- End of excerpt from Bruno Rassaerts
Look at the end of the man page for pfGeoSet under BUGS. PFGS_POLYS is
broken for IRIS GL! To solve this, I triangulated such polygons myself. Or
better yet, use OpenGL. We haven't noticed any significant performance
problems with our RE2 running OpenGL.
--
Fred Clyne
Cambridge Research Associates office: 703-790-0505 x 7211
1430 Spring Hill Road, Suite 200 fax: 703-790-0370
McLean, VA 22102 email: fred++at++cambridge.com
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