On 1 Jul 2009, at 16:40, Hall, Theodore wrote: >> From: Carsten Neumann [mailto:[email protected]] >> Sent: Wednesday, July 01, 2009 09:42 > > [snip] > >> hm, you have not really mentioned what problem the degenerate >> triangles >> are causing for you, can you give us an idea what you are trying to >> do? >> In the case of the stitched strips degenerate tris can not be >> avoided, >> in the other case they are not nice, but the hardware should just >> discard them and since their number is low compared to real >> triangles. >> >> @Johannes: do you have a description of the striper (other than the >> code >> ;) ), e.g. a paper about it? do you recall if it always puts a >> degenerate tri in a strip to support stitching and where in the >> strip it >> is placed (I'm wondering if the problem can be fixed simply by >> decreasing the length of the strip by one?). Thanks! > > > Hi Carsten. > > Actually, the only problem that the degenerate triangles have caused > me is > that I thought I must be doing something wrong. Although the on- > screen > result looked correct, I suspected it wasn't robust, and I spent > about a > day trying to figure out what I was doing wrong, until I finally > searched > the mail archives and discovered that it was "a feature, not a > bug." I > can live with that. > > Personally, I would rather see the triangle strips divided to remove > the > degenerate triangles: more strips, no degenerate triangles. From my > user > perspective, that's the expected behavior.
But than you have to send 3 vertices and not just 2 for the left/left or right/right triangle. Therefore a swap is the better solution for a optimisation process. regards johannes > > (My current task is to marry OpenSG to a physics simulation of tearing > cloth while preserving colors and textures across the tear. Tears > produce new vertices and change triangle position indices, but > should not > change color or texture indices. The physics engine works with > discrete > triangles, so I need to decompose triangle-strips and triangle-fans > into > discrete triangles, reconfigure the index mapping to join positions > and > normals in one index and isolate colors and textures in other indices, > and mate these triangles to the physics triangles. Ultimately, the > degenerate triangles disappear after they fail to mate with any > physics > triangles.) > > -- > > Ted > -------- Dr.-Ing. Johannes Behr tel: +49-6151-155-510 Fraunhoferstr. 5 fax: +49-6151-155-196 D-64283 Darmstadt skype: johannesbehr Germany web: www.igd.fhg.de/www/igd-a4/ ------------------------------------------------------------------------------ _______________________________________________ Opensg-users mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/opensg-users
